CN209759392U

CN209759392U - Coal gas production H2Device for producing CO raw material gas

Info

Publication number: CN209759392U
Application number: CN201821746645.XU
Authority: CN
Inventors: 赵春风; 丁艳宾; 赵猛; 马正飞; 杨东昊
Original assignee: Suzhou Gai Wo That Purification Technology Co Ltd
Current assignee: Suzhou Gai Wo That Purification Technology Co Ltd
Priority date: 2018-10-26
Filing date: 2018-10-26
Publication date: 2019-12-10
Anticipated expiration: 2028-10-26

Abstract

The utility model discloses a coal gas production H₂A device for producing CO raw material gas. The device comprises: a first pretreatment device for pretreating the raw material gas(ii) a The flow dividing device is connected with the first pretreatment device or the gas raw material gas output port and is provided with a first part gas outlet and a second part gas outlet; a pressure swing adsorption device connected with the first pretreatment device or the first part gas outlet for separating CO and N from the first part gas by a pressure swing adsorption method₂(ii) a A shift reactor connected to the second part gas outlet of the flow divider for performing shift reaction on the second part gas to convert CO in the gas into H₂to obtain CO₂、H₂And N₂The reaction gas of (3); h₂A separation device connected to the shift reactor for separating H from the reaction gas₂. The utility model provides a thought of the raw material gas of synthetic ethylene glycol of coal gas preparation, provided corresponding device, for coal gas comprehensive utilization provides a new technical route, further improved the economic value of coal gas.

Description

Coal gas production H2Device for producing CO raw material gas

Technical Field

The invention belongs to the technical field of chemical industry, and relates to a method for producing H from coal gas₂A method and a device for producing CO raw material gas.

Background

In recent years, the industry in China is continuously and rapidly developed, the yield of the steel coking industry is increased year by year, and the statistical result in 2014 according to the national statistical bureau shows that in 2013, the pig iron yield in China reaches 7.08 hundred million tons, the coke yield reaches 4.79 hundred million tons, and the crude steel yield reaches 7.78 hundred million tons. In these industrial processes, a large amount of coke oven gas (coking), blast furnace gas (iron making) and converter gas (steel making), referred to as "three gases" for short, is generated. The total amount of the by-product gas can reach billions of cubic meters every year and is in a trend of increasing year by year. Meanwhile, other ferrous metals and nonferrous metals can also produce blast furnace gas, converter gas and tail gas with gas components similar to those of the blast furnace gas and the converter gas in the smelting process.

In the "third gas" of the steel mill, the blast furnace gas has the lowest effective gas content, but the largest discharge amount. The blast furnace gas comprises the following main components: CO, CO₂，N₂，H₂，CH₄Etc., wherein the content of CO is about 25%, and CO₂And N₂The content of (A) is about 15% and 55%, respectively, H₂、CH₄The content of (A) is small. The heat value of blast furnace gas is low and is only 3300-3800 kJ/Nm 3. Due to CO in blast furnace gas₂，N₂The heat generated by combustion is not involved, combustion is not supported, and on the contrary, a large amount of heat generated in the combustion process is absorbed, so that the theoretical combustion temperature of blast furnace gas is lower, only about 1300 ℃, even only about 900 ℃. The blast furnace gas is unstable in combustion at normal temperature, and a common industrial furnace cannot only use the blast furnace gas as a fuel and needs to be mixed with high-heat-value gas such as coke oven gas or converter gas for use, but the blast furnace gas and the coke oven gas or the converter gas are mixed for use, so that the fluctuation of the heat value is large, the high requirement is provided for a combustion device, and the product quality is influenced to different degrees. Because most of enterprises have rich blast furnace gas and high-calorific-value gas, the blast furnace gas is diffused to different degrees, which not only pollutes the environment, but also wastes energy. How to effectively utilize the blast furnace gas with low heat value, high impurity content, huge yield, difficult purification and serious environmental pollution is a difficult problem to be solved at home and abroad.

At present, blast furnace gas is generally used for combustion, but because the blast furnace gas has low heat value, high content of non-combustible components and poor combustion efficiency and utilization rate, a great amount of valuable CO which can be used as chemical raw materials with high additional value is wasted. Converter gas is generally used for combustion or power generation at present, but due to low calorific value, the combustion efficiency and the utilization rate are poor, and the benefit generated by power generation is far lower than the benefit of using the converter gas as a chemical raw material after treatment to produce high-added-value chemical products.

In addition, the basic principle of Pressure Swing Adsorption (PSA) is to realize the separation or purification of gas by periodic Pressure shift process by utilizing the difference of Adsorption characteristics of gas components on solid materials. In either adsorption, the lower the temperature and the higher the pressure, the greater the amount of adsorption in the adsorption equilibrium for the same gas to be adsorbed (adsorbate). Conversely, the higher the temperature and the lower the pressure, the smaller the amount of adsorption. If the temperature is substantially constant, adsorption under pressure, methods using reduced pressure (vacuum), purging with weakly adsorbing gases, or low pressure desorption are known as pressure swing adsorption. Pressure swing adsorption generally includes adsorption, desorption (evacuation, purge, or evacuation plus purge), and, if present, pressure equalization, pressurization, sequential release, reverse release, displacement, and the like. It can be seen that pressure swing adsorption is the adsorption and desorption by varying the pressure. Energy loss exists when pressure changes, and the existing pressure swing adsorption method does not recover the energy, so that energy waste is caused, the economic benefit of pressure swing adsorption is reduced, and the pressure swing adsorption method is used under the condition of overhigh pressure, and the cost is overhigh.

With the development of industry, there are many cases of gas separation under high pressure conditions, and the higher the operating pressure, the higher the operating energy consumption. On the other hand, in the industrial operation of pressure swing adsorption, the pressure and pressure reduction of a plurality of devices are frequently changed, so that the energy is difficult to recover well.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a process for preparing raw gas for synthesizing glycol, which has simple process flow, low equipment investment and low power consumption, takes blast furnace gas and/or converter gas as the main component and is prepared by multiple treatment steps, the process not only can relieve the current situations of domestic energy shortage and serious blast furnace gas waste, but also can further increase the economic and environmental benefits of gas, particularly blast furnace gas; it is another object of the present invention to provide a device thereof.

The technical scheme is as follows: the invention relates to a method for producing H by using coal gas₂A method for producing a/CO feed gas, comprising the steps of:

1, dividing coal gas into two parts in a source or a first pretreatment process, wherein the first part of gas is subjected to the first pretreatment process and then is subjected to CO and N separation by a pressure swing adsorption method₂Obtaining CO; the second part of gas converts CO in the gas into H through conversion reaction₂To obtain CO-containing₂、H₂And N₂And then separating H from the reaction gas₂；

Step 2, mixing the CO and H obtained in the step 1₂As H₂a CO raw material gas.

Said H₂CO raw material gasFor alcohols.

The coal gas mainly comprises blast furnace gas or converter gas; the coal gas may also contain one or a mixture of more of other tail gases or purge gases.

The volume fraction of the first part of gas is 15-70%, and the volume fraction of the second part of gas is 30-85%.

Separating CO and N by pressure swing adsorption of the second part of gas and the first part of gas₂And (3) carrying out a shift reaction after mixing the displacement tail gas or/and the cis-bleed gas generated in the CO obtaining process.

The first pretreatment process comprises dust removal, phosphorus removal, arsenic removal, dehydration, dehydrogenation and deoxidation, desulfurization and CO removal₂Removing CH₄And one or a combination of several steps in the removal of the heavy fraction.

Further, the first pretreatment process comprises desulfurization and CO removal₂Removal of CO₂In-phase with desulfurization or CO removal₂After the desulfurization step.

Further, the first preprocessing flow also comprises CH removal₄Or/and dehydro-deoxygenation; except CH₄After the desulfurization step; dehydro-deoxygenation in CH removal₄After the step (b); the coal gas is divided into two parts after desulfurization, demethanization or dehydrogenation and deoxidation.

The second part of gas is processed by a second pretreatment process before the shift reaction, the second pretreatment process comprises a first pretreatment step and a separate pretreatment step when the second pretreatment process is mixed with the first part of gas, and the second pretreatment process comprises dust removal, phosphorus removal, arsenic removal, dehydration, dehydrogenation and deoxidation, desulfurization and CO removal₂Removing CH₄And one or a combination of several steps in the removal of the heavy fraction.

In the first and second pretreatment processes, the CH removal₄Is to remove CH by catalytic combustion reaction₄(ii) a The dehydrogenation and deoxidation are carried out by a catalytic reaction method.

From said CO-containing₂、H₂And N₂Separating the reaction gas to obtain H₂In the meantime, by CO removal₂And N₂Wherein N is removed₂CO removal by pressure swing adsorption separation₂By pressure swing adsorption separation or absorption.

CO removal in a first pretreatment Process₂By pressure swing adsorption separation or absorption, in which the absorbent is CO-removed in the first pretreatment stage₂After being used in the second part of gas H₂CO in the process₂And (4) removing.

Coal gas production H₂A plant for a/CO feed gas comprising:

The first pretreatment device is used for pretreating the gas feed gas;

The flow dividing device is connected to the first pretreatment device or the gas raw material gas output port, is provided with a first part gas outlet and a second part gas outlet and is used for dividing the gas into two parts;

A pressure swing adsorption device connected with the first pretreatment device or the first part gas outlet and used for separating CO and N from the first part gas by a pressure swing adsorption method₂；

A shift reactor connected to the second part gas outlet of the flow dividing device for performing shift reaction on the second part gas to convert CO in the gas into H₂To obtain CO-containing₂、H₂And N₂The reaction gas of (3);

H₂A separation device connected to the shift reactor for separating CO from the gas containing CO₂、H₂And N₂Separating the reaction gas to obtain H₂。

The coal gas is used for producing H₂The device for producing the alcohol also comprises a device for producing the alcohol, a CO outlet connected with the pressure swing adsorption device and H₂H of the separation apparatus₂And the outlet is used for reacting and synthesizing alcohol with the carbon atom number more than or equal to 2.

The first pretreatment device is connected to a raw gas outlet mainly containing blast furnace gas or converter gas.

The raw material gas output port mainly containing blast furnace gas or converter gas is also connected with the inlet ports of coke oven gas, other tail gas or exhausted gas.

The pressure swing adsorption device is connected with the shift reactor through a pipeline and is used for separating CO and N from the first part of gas by the pressure swing adsorption method₂And (3) mixing the replacement gas or/and the cis-bleed gas generated in the CO obtaining process with the second part of gas, and then carrying out a shift reaction.

The first pretreatment device comprises a dust removal device, a phosphorus removal device, an arsenic removal device, a dehydration device, a dehydrogenation and deoxidation device, a desulfurization device and CO removal₂Plant, CO removal plant or CH removal₄One or a combination of several of the devices. The corresponding functions are dust removal, phosphorus removal, arsenic removal, dehydration, dehydrogenation and deoxidation, desulfurization and CO removal₂CO or CH removal₄One or a combination of several of them. The second pretreatment device works in the same way.

Further, the first pretreatment device comprises a desulfurization device and CO removal₂Apparatus, CO removal₂Integration of the plant with a desulfurization plant or CO removal₂The unit is located downstream of the desulfurization unit.

Further, the first preprocessing device also comprises a CH removing device₄A device or/and a dehydrogenation deoxidation device; except CH₄The device is arranged at the downstream side of the desulfurization device; the dehydrogenation and deoxidation device is in CH removal state₄The downstream side of the apparatus; shunting device and CH removing device₄The gas outlet of the device, the gas outlet of the desulphurization device or the gas outlet of the dehydrogenation and deoxidation device are connected. I.e. when containing the CH₄When installed, remove CH₄The unit being downstream of the desulphurisation unit, the desulphurisation unit and the CO removal unit₂When the devices are separated, remove CH₄The device is arranged at the downstream side of the desulfurization device and used for removing CO₂The upstream side of the apparatus; when the dehydrogenation-deoxidation apparatus is included, the dehydrogenation-deoxidation apparatus is located on the downstream side of the desulfurization apparatus, the desulfurization apparatus and the CO removal₂When the apparatus is separated, the dehydrogenation and deoxidation apparatus is positioned at the downstream side of the desulfurization apparatus to remove CO₂On the upstream side of the apparatus, if CH removal is included₄The dehydrogenation and deoxidation device is in CH removal₄Downstream of the device.

For different combinations, it is clear that the pressure swing adsorption unit is connected to the tail of the first pretreatment unit (i.e. after the last unit of the last first pretreatment unit is finished) or to the first partial gas outlet of the splitting unit. The shunting device is arranged at the front end, the middle unit or the tail part of the first pretreatment device.

the gas inlet of the shift reactor is connected with a second pretreatment device, the second pretreatment device comprises a first pretreatment device and an independent pretreatment device, the first pretreatment device passes through when two parts of gas are in a mixed state, the independent pretreatment device is connected with the second pretreatment device through a flow dividing device, and the second pretreatment device comprises a dust removal device, a phosphorus removal device, an arsenic removal device, a dehydration device, a dehydrogenation and deoxidation device, a desulfurization device and a CO removal device₂Device, remove CH₄One or more of the devices and recombination removal devices. The separate pretreatment device may also be dispensed with, in which case the shift reactor is connected directly to the second gas outlet of the dividing device.

H₂The separation device is a second pressure swing adsorption device, or H₂The separation device adopts a series absorption method to remove CO₂The device and a third pressure swing adsorption device. H₂During extraction, CO can be directly absorbed by the second pressure swing adsorption device₂、H₂And N₂CO in the reaction gas₂And N₂Removing and separating to obtain H₂Or by first removing CO by absorption₂CO in the reaction gas of the plant₂Removing H by a third pressure swing adsorption device₂And N₂Separating to obtain H₂。

The pressure swing adsorption apparatus, the second pressure swing adsorption apparatus and the third pressure swing adsorption apparatus are named only for the sake of clarity, and are not limited in structure₂The apparatus, the pressure swing adsorption decarbonization apparatus, and the like are not intended to limit the structure of the apparatus, but are for the purpose of clarifying the present invention.

CO removal in a first pretreatment unit₂The device is a pressure swing adsorption method for removing CO₂CO removal by means of apparatus or absorption₂apparatus for CO removal by absorption₂In the device, the absorption method in the first pretreatment device removes CO₂Suction of deviceThe liquid collecting outlet is connected with H₂Absorption CO removal in a separation plant₂Provided is a device.

In addition, in the separation process, more unit operations of pressure swing adsorption impurity removal are needed, the energy consumption is high due to high operating pressure in the pressure swing adsorption process, the operation change of pressure rising and pressure reducing is frequent, when the pressure difference fluctuation and the energy fluctuation are large and the impact load is large, the allowable fluctuation range of the conventional energy recovery equipment is exceeded, the service life of the machine equipment is shortened, various potential hazards such as safety and the like can be caused, even the machine equipment cannot work normally, and the energy is difficult to recycle. The invention couples the normal adsorption separation process, the energy recovery process and the pressurization process of certain gas or liquid together, recovers energy, has high energy utilization rate and simple process, reduces the operation cost of pressure swing adsorption, and expands the living space of pressure swing adsorption from the cost perspective. The energy recovery system which is coaxially driven and consists of the expander, the motor, the compressor or the pump is mainly used for energy recovery operation, and the equipment has the advantages of compact structure, high overall efficiency, low overall equipment cost and low operation cost, and has good economic benefit.

In the pressure swing adsorption process described above, the following method may also be used:

A method of energy recovery using pressure swing adsorption comprising the steps of: recovering energy of gas in the pressure reduction process in the pressure swing adsorption work by using an expansion machine; dampening the fluctuations in gas pressure at the gas inlet and/or gas outlet of the expander by means of a fluid damping device; alternatively, the fluctuation of the rotation speed of the expander is suppressed by a rotation resistance device on the rotation shaft of the expander.

The fluid buffer device is selected from one or a combination of a plurality of regulating valves or buffer tanks; the rotation resistance device is a flywheel.

The pressure reduction process refers to the process of pressure change in pressure equalization, pressurization, replacement, pressurized flushing, forward release or reverse release and the like.

In one embodiment, the expander drives the generator to generate electricity, the electricity generated by the generator is used for other equipment needing electricity, or the electricity generated by the generator is used for compressing gas or liquid needing pressure boosting in the pressure swing adsorption process through the compressor.

The input current of a motor connected with the compressor is controlled to supplement the required electric energy; the fluctuation of the electric power input to the motor can be stabilized by the battery pack or the capacitor pack.

In one embodiment, the electrical energy generated by the generator is incorporated into an electrical grid, which serves to smooth out fluctuations in the electrical energy generated by the expander by means of the containment capacity; the electric energy obtained from the power grid is used for other equipment needing electric power, or the compressor is used for compressing gas needing pressure boosting in the pressure swing adsorption process.

In one embodiment, the rotating shaft of the expander is coaxially connected with the rotating shaft of the motor, and the expander and the motor drive the compressor to work together.

Based on the above method, the following device can also be adopted:

A pressure swing adsorption apparatus comprising:

1) At least one high pressure adsorption column;

2) The energy recovery device comprises an expander and is used for recovering the energy of the high-pressure gas discharged from the high-pressure adsorption tower;

A fluid buffer device is connected to a gas inlet and/or a gas outlet of the expander;

Alternatively, a rotation resistance device is provided on the rotary shaft of the expander.

In one embodiment, the high pressure adsorption column is connected to the low pressure adsorption column via an energy recovery device.

In one embodiment, the pressure swing adsorption unit further comprises a generator, and the expander is connected to the generator.

The generator is connected with other equipment needing electric power, or the generator drives the compressor to compress the gas or liquid needing boosting in the pressure swing adsorption process.

The generator is connected to an electrical grid, which serves to smooth out fluctuations in the electrical energy generated by the generator by means of the holding capacity.

In one embodiment, the pressure swing adsorption device further comprises a compressor and a motor, and a rotating shaft of the expander is coaxially connected with a rotating shaft of the motor, and the compressor is driven by the expander and the motor together to work.

The motor is also provided with a battery pack or a capacitor pack.

And a buffer tank is arranged at the gas inlet and/or the gas outlet of the compressor.

Compared with the common pressure swing adsorption method, the pressure swing adsorption method of the method and the device of the invention adds an energy recovery process, couples the normal adsorption separation process, the energy recovery process and a certain gas or liquid pressurization process together, recovers energy, improves the energy utilization rate of the system, reduces the operation cost of the pressure swing adsorption, expands the living space of the pressure swing adsorption from the cost perspective, has simple process, high safety factor, high automation degree of a unit, simple and convenient operation, small floor area of equipment, ensures the product purity, ensures the recovery rate, is flexible to operate, and reduces the number and the size of tower equipment.

Has the advantages that:

The invention provides a concept for preparing the raw gas for synthesizing the ethylene glycol by various treatment devices from the raw gas of blast furnace gas and/or converter gas and the like, not only provides a new technical route for the comprehensive utilization of the gas, particularly the blast furnace gas, but also further improves the economic value of the gas, particularly the blast furnace gas; by the device, H is prepared from raw material gas such as blast furnace gas, converter gas and the like₂The nitrogen concentration of the CO raw material gas can meet the industrial grade requirement and can be recycled; the integral process for preparing raw gas for synthesizing glycol from raw gas such as blast furnace gas, converter gas and the like is obtained through a large number of experiments, simulation calculation, on-site research of steel plants and years of engineering design experience, and material matching and heat utilization are integratedThe process flow is optimized by the process consideration.

Drawings

FIG. 1 is blast furnace gas production H₂A flow chart of a process method of a CO raw material gas;

FIG. 2 is H in example 1₂a process flow diagram of a preparation method of CO raw material gas;

FIG. 3 is H in example 2₂A process flow diagram of a preparation method of CO raw material gas;

FIG. 4 is H in example 3₂A process flow diagram of a preparation method of CO raw material gas;

FIG. 5 shows a graph showing a graph represented by H in comparative example 1₂A process flow diagram of a preparation method of CO raw material gas;

FIG. 6 is a block diagram of an energy recovery device for use in a pressure swing adsorption process;

FIG. 7 is a block diagram of another energy recovery device for use in a pressure swing adsorption process;

FIG. 8 is a two-column pressure swing adsorption H purification integrated with an energy recovery device₂A device;

FIG. 9 is a three-tower pressure swing adsorption purification H incorporating an energy recovery device₂A device;

FIG. 10 is the blast furnace gas preparation H₂a plant diagram of a CO feed gas;

the system comprises an adsorption tower 1, a turbine expander 2, a compressor 3, a motor 4, an evacuation gas buffer tank 5, a vacuum pump 6, a reverse-release gas buffer tank 7, a reverse-release gas compressor 8, a flywheel 9, a capacitor bank 10, a compressed gas inlet buffer tank 11, a compressed gas outlet buffer tank 12, a turbine inlet high-pressure buffer tank 13, a turbine outlet high-pressure buffer tank 14, a turbine inlet low-pressure buffer tank 15, a turbine outlet low-pressure buffer tank 16, a turbine expander 17, an incoming gas buffer tank 18, a tower top product gas buffer tank 19, a first-stage turbine outlet heat exchanger 20 and a second-stage turbine outlet heat exchanger 21.

Detailed Description

H provided by the invention₂The production method of the/CO raw material gas mainly utilizes blast furnace gas, converter gas and the like as raw materialsOr main raw materials (such as more than 80% and 90% of the main raw materials). The coal gas may also contain one or more of coke oven gas, other tail gas or exhausted gas.

The gas composition of the coal gas mainly comprises: n is a radical of₂、H₂、CO、CO₂、O₂、CH₄、H₂s, COS, etc., in some typical blast furnace gas, the composition includes, in volume percent: n is a radical of₂ 40～65％、H₂ 0.5～5％、O₂ 0.2～5％、CO₂ 10～30％、CO 10～30％、CH₄ 0.1～2.0％、H₂S 5～400ppm、COS 0.1～100ppm。

Before the raw materials such as coal gas enter the process and the equipment in the patent, the corresponding pretreatment processes such as impurity removal and the like can be carried out by a conventional method; these pretreatments are not particularly limited.

"H" as referred to in the invention₂the/CO raw material gas mainly refers to CO and H₂They are present alone, H₂The application of the/CO raw material gas can be used for synthesizing different chemical raw materials on different catalysts. In the present invention, the compound containing H is obtained₂And H of CO₂After the/CO raw gas, it is mainly applied to the production of ethylene glycol. Due to the method, H is prepared₂The high quality of CO raw material gas can also be used for preparing other alcohols with the carbon number more than or equal to 2 and other processes, such as preparing ethanol from methanol, and realizing chain extension reaction by adding CO so as to increase one or more carbon atoms (carbonylation reaction), and then performing hydrogenation H when needed₂And the product obtained.

Coal gas production H₂A method for producing a/CO feed gas, comprising the steps of:

In step 1, CO and nitrogen are separated by adopting a pressure swing adsorption separation method (or called a pressure swing adsorption method), and adsorbents conventional in the field, such as copper-loaded or silver-loaded adsorbents or metal organic framework adsorbents (MOFs, ZIFs) and Metal Organic Polyhedrons (MOPs), can be adopted; the support of the adsorbent may be activated carbon, alumina, silica gel, molecular sieves, honeycomb ceramics, monazite, honeycomb metal, metal sheet, corrugated filler, corrugated sheet, fiber (cloth) material and structure, woven fabric, metal foam, ceramic foam, graphite-based foam, and the like. The CO and the nitrogen are separated by adopting a pressure swing adsorption separation method, the adsorption pressure of pressure swing adsorption is about 0.02-10 MPa, the operation temperature is 0-150 ℃, in some embodiments, the adsorption pressure of pressure swing adsorption is 0.2-0.8 MPa, the operation temperature is 20-80 ℃, the volume fraction of industrial grade nitrogen extracted by pressure swing adsorption is more than or equal to 99.2%, the industrial grade nitrogen meets the industrial nitrogen standard GB3864-2008 and the updated version thereof, and the industrial grade nitrogen can be directly used or sold as a product. When the pressure swing adsorption separation method is adopted to separate CO and nitrogen, a temperature swing adsorption method is required to be added in front of a pressure swing adsorption unit to remove water and heavy components, and because the water and the heavy components can influence the effect of the subsequent pressure swing adsorption step and can generate adverse influence on the adsorbent, the separation capacity of the pressure swing adsorption of the adsorbent can be reduced, even irreversible damage can be caused to the adsorbent, the adsorbent is degraded, even inactivated, the service life of the adsorbent is shortened, especially the damage to the adsorbent for separating CO and nitrogen is more serious, and the adsorbent is rapidly degraded, inactivated and unusable. When more than one set of pressure swing adsorption device is adopted for series connection, the temperature swing adsorption separation unit is arranged in front of the separation unit of the first set of pressure swing adsorption method, CO and nitrogen are separated by the pressure swing adsorption separation method, nitrogen which does not meet the industrial standard is obtained, when the pressure of the nitrogen is more than 0.15MPa, the nitrogen can enter a residual pressure recovery system, the pressure energy of the nitrogen is recovered, when the pressure swing adsorption method is adopted, an energy recovery device can be added into the pressure swing adsorption device, and the pressure energy wasted in the pressure swing adsorption process is recovered while the pressure swing adsorption separation process is completed.

The method comprises the steps of splitting incoming coal gas at a source or in a first pretreatment process (including any intermediate link of the first pretreatment or after the first pretreatment is finished), separating CO and nitrogen by adopting a pressure swing adsorption separation method after a first part of gas (the volume fraction of the first part of gas is 15-70%) passes through the first pretreatment process, sending the obtained pure CO into an intermediate gas storage tank, using the pure CO as a raw material gas for synthesizing alcohol such as ethylene glycol to be used by a next step of alcohol synthesis such as an ethylene glycol device, and sending the CO into the intermediate gas storage tank after the pressure of the CO is adjusted to be 0.15-10 MPa so as to be directly used for the subsequent synthesis of the ethylene glycol. And performing a shift reaction on the second part of gas (the volume fraction of the second part of gas is 30-85%) to prepare hydrogen, wherein the reaction pressure is 0.3-20 MPa, the reaction temperature is 160-550 ℃, in some embodiments, the reaction pressure is 0.3-4 MPa, and the obtained gas is subjected to impurity removal and hydrogen purification steps to obtain pure hydrogen, and the pure hydrogen is sent to an intermediate gas storage tank and used as a raw material gas for synthesizing the ethylene glycol for a next device for synthesizing the ethylene glycol, and similarly, the hydrogen can be regulated to have the pressure of 1.5-20 MPa and then sent to the intermediate gas storage tank to be directly used for synthesizing the subsequent ethylene glycol. Because the CO content is lower, the heat release of the shift reaction is less, more gas is not reacted, and the total heat carrying capacity is larger, so that the temperature rise is less, the reaction severity is reduced, and the service life of the catalyst is prolonged. The incoming gas is divided into two parts according to the following process requirements and CO and/or H of the incoming gas as a supplementary external gas source₂The method is characterized in that the gas required by purifying only the feed gas is fully utilized, and the carbon-hydrogen ratio for producing glycol is suitable, the volume fraction of the first part of gas is 30-35%, and the volume fraction of the second part of gas is 65-70%.

The basic principle of CO shift is:

It is a reversible exothermic chemical reaction of equal volume, and from the viewpoint of chemical reaction equilibrium, it can raise pressure and chemical equilibriumThe balance is not affected, but both the reduction of the reaction temperature and the increase of the water vapor content in the reactants favor the reaction towards the formation of CO₂And H₂Is performed in the same direction. The reactor adopts an isothermal transformation reactor. The shift reaction may be carried out using catalysts conventional in the art, for example using copper-based and/or iron-based and/or cobalt-molybdenum based catalysts comprising copper and/or iron and/or zinc and/or aluminium and/or manganese and/or cobalt and/or molybdenum and/or cerium and/or magnesium and/or chromium and/or potassium and/or vanadium and/or nickel and/or titanium and/or palladium and/or platinum and/or ruthenium and/or rhodium and/or sodium and/or rubidium and/or cesium and/or niobium and/or zirconium and/or rare earth elements and/or oxides of alkali metals and/or their sulfides and/or their soluble salts and/or complex metal oxides formed between them. The carrier is activated carbon, alumina, silica, magnesia, titania, silica gel, molecular sieve, hydrotalcite, spinel, honeycomb ceramic, monazite, honeycomb metal, metal plate, corrugated filler, corrugated plate, fiber (cloth) material and structure, braided fabric, metal foam, ceramic foam, graphite-based foam, copper and/or iron and/or zinc and/or aluminum and/or manganese and/or cobalt and/or molybdenum and/or cerium and/or magnesium and/or chromium and/or potassium and/or vanadium and/or nickel and/or titanium and/or palladium and/or platinum and/or ruthenium and/or rhodium and/or sodium and/or rubidium and/or cesium and/or niobium and/or zirconium and/or rare earth elements and/or oxides of alkali metals and/or sulfides and/or soluble salts thereof and/or complex salts thereof formed between the above Metal oxides, and the like.

The gas after the shift reaction mainly contains hydrogen, nitrogen and carbon dioxide as well as some other trace impurities, and unreacted water vapor may also exist. Firstly, the temperature is reduced to remove water and then CO is removed₂And nitrogen.

In one embodiment, the first pretreatment process comprises dedusting, dephosphorizing, dearsenifying, dehydrating, dehydrodeoxygenating, desulfurizing, and CO removing₂Removing CH₄And one or more steps in the heavy component removal are combined, the content of harmful impurities in the first part of gas is controlled to be less than or equal to 1.15ppm of sulfide and NH after the first part of gas is purified by a first pretreatment process₃≤200ppm，H₂≤1000ppm，O₂≤1000ppm，H₂O≤100ppm，Cl⁺less than or equal to 0.03ppm, less than or equal to 0.1ppm of arsenide, less than or equal to 1mg/Nm of tar and dust³Naphthalene is less than or equal to 1mg/Nm³. Further controlling the content of harmful impurities to be less than or equal to 0.1ppm of sulfide and Cl⁺≤0.01ppm，H₂≤100ppm。

In one embodiment, the first pretreatment process comprises desulfurization and CO removal₂Removal of CO₂In-phase with desulfurization or CO removal₂After the desulfurization step. The removal of blast furnace gas and/or converter gas is the first to be done because it contains trace amounts of sulfur, which can adversely affect the various catalysts (dehydrodeoxygenation, shift, product gas requirements, even demethanization catalysts) and sorbents (CO and nitrogen separation) in the subsequent steps, even causing deactivation, shortening of their useful life, and sulfur levels below the minimum sulfur levels required by some sulfur tolerant catalysts. And because the blast furnace gas and/or converter gas of the incoming material can be higher in the initial temperature, the reaction speed and the desulfurization effect of the metal oxide desulfurizer are facilitated. The removal of sulfur or sulfur-containing impurities can be carried out by a method commonly used in the art such as adsorption, membrane separation, solid desulfurizing agent containing iron, manganese, zinc, copper, nickel, calcium, or tin oxide or hydroxide or complex metal oxide formed therebetween, low-temperature methanol washing, propylene carbonate method, N-methylpyrrolidone method, dimethyl ether method of polyethylene glycol, methylpropyl ether method of polyethylene glycol, tributyl phosphate method, hot potash method, activated hot potash method, MEA method, DEA method, MDEA method, DIPA method, propylene carbonate method + DIPA, propylene carbonate method + glycolamine method, sulfolane + DIPA method, sulfolane + MDEA method, methanol + secondary amine method, alkylol amine solution method, MEA method, DEA method, MDEA method, ammonia washing method, caustic soda method, ADA method (stretford method), tannin extract method, LO-CAT method, lflox method, and the like, The Sulfint method, Konox method, Bio-SR method, naphthoquinone method (Takahax method), metallophthalocyanine method (PDS method), G-V (modified arsenic alkali method), arsenic alkali method, MSQ method, Sulfolin method, EDTA method, wet oxidation method, alkali absorption method, limestone-gypsum method, ammonia method, magnesium method, ammonium phosphate method, sodium organic acid-gypsum method, lime-magnesium method, calcium method, dry circulating fluidized bed methodzinc oxide process, urea process, complex absorption process, charged dry absorbent spray process, plasma process, electron beam process, double alkali process, alkali sulfide process, and combinations thereof. The method preferably adopts a solid desulfurizing agent and an absorption liquid such as an active DEA/MDEA absorption method, and has good desulfurizing effect and low cost. Wherein the removed sulfur is sent to a sulfur recovery system, and the sulfur in the gas is removed to 0.01-0.1 ppm after the raw material gas is desulfurized. When the absorption method is employed, the absorbent such as DEA/MDEA has an absorption capacity for both sulfur and carbon dioxide, and sulfur and carbon dioxide can be removed simultaneously. The desulfurization is carried out at 0.2 to 10MPa, 20 to 700 ℃, and in some embodiments (0.2 to 1.6MPa, 20 to 400 ℃, e.g., 280 to 400 ℃ for some solid desulfurizers of metal oxides, and 20 to 70 ℃ for absorption solutions). The CO removal can be realized by adopting an absorption method₂The desulfurization is carried out synchronously, and a step of fine desulfurization by using a solid desulfurizing agent is preferably arranged.

When the feed gas contains too high content of organic sulfur in sulfur, the organic sulfur can be converted into H by catalytic hydrogenation reaction or catalytic hydrolysis reaction₂S, then performing desulfurization to ensure that the sulfur content of the treated gas can meet the requirement, and when the incoming gas contains sulfur, the main SO₂And the content is too high, SO can be caused by catalytic hydrogenation reaction₂conversion to H₂And S, desulfurizing to enable the sulfur content of the treated gas to meet the requirement. The catalyst for catalyzing hydrogenation reaction comprises metals of iron and/or copper and/or cobalt and/or manganese and/or molybdenum and/or zinc and/or aluminum and/or nickel and/or titanium and/or zirconium and/or tungsten and/or cerium and/or oxides thereof and/or sulfides thereof and/or soluble salts thereof and/or composite metal oxides formed among the above as active components, and one or more of the metals of titanium, zirconium, manganese, iron, nickel, cobalt, copper, molybdenum, tungsten, zinc, cobalt and cerium and/or oxides thereof and oxides of silicon, rare earth, alkali metal, alkaline earth metal and transition metal and/or sulfides thereof as auxiliary agents. The carrier is active carbon, alumina, silica, magnesia, titania, silica gel, molecular sieve, honeycomb ceramic, monazite, honeycomb metal, metal plate, corrugated filler, corrugated plate, fiber (cloth) material and structure, or woven fabricExamples of the material include metal foam, ceramic foam, and graphite-based foam. The catalyst for catalyzing hydrolysis reaction comprises metals of magnesium, lanthanum, barium, aluminum, titanium, zirconium, cerium, potassium, calcium, cobalt, molybdenum, iron, copper, manganese, zinc, nickel and tungsten, oxides of the metals and/or the sulfides of the metals, and one or more of oxides of the metals of titanium, zirconium, nickel, cobalt, molybdenum, cobalt and cerium, oxides of the metals and/or the sulfides of the metals is used as an active component. The carrier is activated carbon, alumina, silica, magnesia, titania, silica gel, molecular sieve, honeycomb ceramic, monazite, honeycomb metal, metal plate, corrugated filler, corrugated plate, fiber (cloth) material and structure, braided fabric, metal foam, ceramic foam, graphite-based foam, etc.

CO₂Can affect the separation effect of the step of separating CO and nitrogen by pressure swing adsorption because of CO₂A certain amount of adsorption on the adsorbent used in the CO and nitrogen separation step results in CO₂And CO, CO₂Low separation coefficient of nitrogen and CO₂The existence of the carbon dioxide can cause that the CO and nitrogen separation step can not obtain high-purity CO and nitrogen, and the separated CO and nitrogen gas contains more CO₂therefore, CO is first removed₂Removal of CO₂The step of (2) requires removal of CO before the CO and nitrogen separation step₂The steps are to ensure that CO and nitrogen can respectively obtain high-purity CO and nitrogen in the CO and nitrogen separation step, and meanwhile, the sequence also conforms to the step-by-step principle of adsorption capacity, the principle of adsorbing low-content components as much as possible and reducing desorption energy consumption, and the loss of adsorption pressure, an intermediate-stage pressurization step and a desorption step is reduced. Removing CO from coal gas₂the step (2) may employ a pressure swing adsorption method, an absorption method, or a combination thereof. Wherein the absorption method comprises: water washing method, low-temperature methanol washing method, propylene carbonate method, N-methylpyrrolidone method, polyethylene glycol dimethyl ether method, polyethylene glycol methyl propyl ether method, Catacarb method (catalytic method)Hot alkaline process), hot potash process, activated hot potash process, modified hot alkaline process, hot carbonate process, amino acid salt process, ammonia water washing process, urea (alkaline) process, G-V (modified arsenic alkaline process), MEA process, DEA process, MDEA process, DIPA process, TEA process, sulfolane + DIPA process, sulfolane + MDEA process, methanol + secondary amine process, alkyl alcohol amine solution process, and MEA process with added active agent, DEA process, MDEA process, TEA process, etc., CO in feed gas after decarburization₂Removing to 0.01-0.8 Vol%, wherein the removed carbon dioxide can be sold as a carbon dioxide product or used as a raw material gas in other processes or discharged after reaching the discharge standard, and removing CO₂When the process is carried out under the conditions of 0.2-20 MPa and 20-150 ℃, in some embodiments (0.2-1.6 MPa and 20-80 ℃), when an absorption method is adopted as a separation unit for decarburization, a trace amount of absorption liquid is usually carried out in gas, and a temperature swing adsorption separation unit is required to be added behind the unit to remove water and some components such as heavy components contained in the gas. Removing components such as water and recombinant components by a temperature swing adsorption method; the adsorbent is molecular sieve, active carbon, alumina, silica gel or their composite bed, and the removed tail gas containing great amount of carbon dioxide may be recovered in the residual pressure recovering apparatus at pressure over 0.15 MPa.

In one embodiment, in addition to the desulfurization and CO removal described above₂Then, the first pretreatment process also includes CH removal₄Or/and dehydro-deoxygenation; by removing CH₄Industrial nitrogen meeting the standards (GB3864-2008 and its newer versions) is available for use. By CH elimination₄CH in the rear feed gas₄Removing to less than or equal to 0.2Vol percent. Due to the removal of CH₄The temperature required for the reaction is higher to remove CH₄After the desulfurization step, the removal is preceded, if desulfurization and CO removal₂Step (c) is divided so as to remove CH₄In the process of removing CO after desulfurization₂The method is beneficial to saving energy and heat exchange equipment and reducing equipment investment and operating cost. In one embodiment, except CH₄The method is mainly characterized in that methane is removed through catalytic combustion reaction of methane under certain temperature and pressure, and the reaction temperature and pressure are respectively controlled to be 200-1000 ℃ (further 250-350 ℃) and 0.1-10 MPa (further)One step is 0.2-1.6 MPa), and the catalyst is prevented from losing activity. The catalyst used may be one conventional in the art, for example, a metal containing iron and/or copper and/or cobalt and/or manganese and/or molybdenum and/or zinc and/or aluminum and/or nickel and/or chromium and/or bismuth and/or magnesium and/or titanium and/or barium and/or ruthenium and/or zirconium and/or cerium and/or lanthanides and/or platinum and/or palladium and/or gold and/or rhodium and/or calcium and/or an oxide thereof and/or a soluble salt thereof and/or a complex metal oxide formed therebetween as an active component. The auxiliary agent is one or more of metals of titanium, zirconium, manganese, iron, nickel, cobalt, copper, molybdenum, tungsten, zinc, cobalt, cerium, aluminum, chromium, bismuth, magnesium, titanium, barium, ruthenium, zirconium, cerium, lanthanum, platinum, palladium, gold, rhodium and calcium and/or oxides thereof and/or soluble salts thereof and/or composite metal oxides formed between the metals and oxides of silicon, rare earth, alkali metal, alkaline earth metal and transition metal. The carrier is activated carbon, alumina, silica, magnesia, titania, silica gel, molecular sieve, honeycomb ceramic, monazite, honeycomb metal, metal plate, corrugated filler, corrugated plate, fiber (cloth) material and structure, braided fabric, metal foam, ceramic foam, graphite-based foam, etc. Except CH₄The content of the rear raw material gas is less than or equal to 0.5 percent, and further CH₄Less than or equal to 0.1 percent. If no industrial nitrogen meeting the criteria is required, the methane removal step may not be employed.

If the oxygen content in the raw material gas such as blast furnace gas and/or converter gas is high (approximately)>0.1% and above in typical gas), it may adversely affect the subsequent shift catalyst, CO and nitrogen separation adsorbent, even cause deactivation, shorten the service life thereof, require prior deoxygenation, and require lower hydrogen and oxygen contents in the product gas; due to the catalytic removal of H in the latter pure CO₂and O₂Will make more CO and O₂The reaction causes waste of CO, the reaction product after dehydrogenation and deoxidation in the catalytic reaction is required to be removed as an impurity, and H is generated after the reaction₂O and CO₂In order to remove the catalyst as an impurity without affecting the subsequent reaction, the removal is required to be increasedImpurity steps and devices remove impurities produced by the catalytic reaction. Moreover, the shift catalyst is deteriorated due to the over-high oxygen content, the shift effect of the shift reactor is poorer and poorer, the purity of the shifted hydrogen is lower and lower, the content of CO in the generated purified tail gas is higher and higher, the unnecessary waste of raw materials is caused, and the environment is not facilitated; and the adsorbent is deteriorated due to the over-high oxygen content, the separation requirement cannot be met along with the time, and the purity of CO cannot meet the preset requirement due to impurities generated by the reaction, so that the CO cannot be used as the raw material gas for synthesizing the glycol for a next glycol synthesizing device. In addition, the high concentration of CO gas required in the raw material gas for synthesizing ethylene glycol needs to satisfy the requirement of H₂Less than or equal to 1000ppm and O₂The concentration of less than or equal to 1000 ppm. Therefore, in the first pretreatment process, after desulfurization, first dehydrogenation and deoxidation (adding trace oxygen and removing hydrogen simultaneously when adjusting the hydrogen-oxygen ratio and deoxidation) are carried out, and H in the coal gas is removed by adopting a selective dehydrogenation and deoxidation catalyst under the conditions of the temperature of 0.1-10 MPa and 50-1000 ℃ (in some embodiments, 0.2-1.6 MPa and 80-250 ℃)₂And O₂. If desulfurization and CO removal₂The step is separated, the dehydrogenation and deoxidation are carried out for removing CO after desulfurization₂if it contains a CH removal₄Step (b), the dehydro-deoxidation is performed in CH removal₄And then, the target is achieved in one step, an adsorbent and a catalyst for protecting subsequent steps are provided, the waste of CO is reduced, the impurity removal step of impurities generated after catalytic dehydrogenation and deoxidation is reduced, the flow is shortened, the investment and the operating cost are reduced, meanwhile, the temperature of the gas in the front is higher, and the reaction temperature of the catalytic dehydrogenation and deoxidation can be met, so that the investment and the operating cost required by heat exchange equipment due to the fact that the gas is placed in the back and needs to be heated are avoided, meanwhile, the sequence also conforms to the step-by-step principle of the reaction temperature, the investment and the operating cost of the heat exchange equipment are reduced, the dehydrogenation and deoxidation are also beneficial to increasing the purity of nitrogen, and the industrial nitrogen. Of course, if the oxygen content in the feed gas is lower (less than or equal to 0.1 percent), the catalytic dehydrogenation-deoxidation step can be put into the pressure swing adsorption to separate CO and N without dehydrogenation-deoxidation in the first pretreatment process₂At the back of the body,Therefore, the adsorbent and the catalyst can not be quickly deactivated, the service life of the adsorbent and the catalyst can not be quickly shortened, but CO waste can be caused, impurity removal equipment and heat exchange equipment are added, the flow is increased, and the investment and the operating cost are increased. The catalyst for dehydrogenation and deoxidation uses palladium and/or platinum and/or cobalt and/or manganese and/or copper metal and/or oxide and/or sulfide thereof as active components, and uses one or more of sodium, potassium, magnesium, titanium, zirconium, vanadium, manganese, iron, nickel, cobalt, copper, molybdenum, tungsten, lanthanum, zinc, silver, palladium, cobalt or cerium metal and/or oxide and/or sulfide thereof and/or complex thereof as auxiliary agents. The carrier is activated carbon, alumina, silica, magnesia, titania, silica gel, molecular sieve, honeycomb ceramic, monazite, honeycomb metal, metal plate, corrugated filler, corrugated plate, fiber (cloth) material and structure, braided fabric, metal foam, ceramic foam, graphite-based foam, etc.

The second part of gas is processed by a second pretreatment process before the shift reaction, the second pretreatment process comprises a first pretreatment step and a separate pretreatment step when the second pretreatment process is mixed with the first part of gas, and the second pretreatment process comprises dust removal, phosphorus removal, arsenic removal, dehydration, dehydrogenation and deoxidation, desulfurization and CO removal₂Removing CH₄And one or a combination of several steps in the removal of the heavy fraction. The content of harmful impurities in the second part of gas after being purified by the second pretreatment process is controlled to be less than or equal to 1.15ppm of sulfide, and O₂≤1％，H₂O≤100ppm，Cl⁺Less than or equal to 0.03ppm, less than or equal to 0.1ppm of arsenide, less than or equal to 1mg/Nm of tar and dust³Naphthalene is less than or equal to 1mg/Nm³. Further controlling the content of harmful impurities to be less than or equal to that of sulfides

0.1ppm，Cl⁺≤0.01ppm，O₂≤0.2％。

Due to the requirement of the product to be produced, the feed gas is required to be divided into two parts, one part is used for preparing high-purity CO gas meeting the preset requirement, and the other part is used for preparing high-purity H meeting the preset requirement₂A gas. However, there are many options for the location of the split point in the flow, such as: incoming gas is directly divided intoOr in the first pretreatment stage, wherein the separation in the first pretreatment stage can be carried out in any intermediate stage of the first pretreatment stage or after the first pretreatment stage has ended, optionally after the desulfurization, after the dechlorination₄After separation, after dehydro-deoxygenation, after CO removal₂Post-split, etc. However, some treatments and impurity removal processes are required for two parts of gas, such as desulfurization, deoxidation (when the oxygen content is higher), and CH removal₄(where industrial nitrogen or environmental requirements are required), so that processes may be common and may be implemented together in a single apparatus, resulting in different locations of the split points in the process and resulting in slightly different subsequent separate pre-treatment processes for the second portion of gas. The location of the split point is influenced by the composition of the incoming gas and the product requirements. For example, both gas portions may be desulfurized and separated after desulfurization, producing high purity H if the oxygen content of the incoming gas is relatively low₂the branched gases of the gas may be directly subjected to shift reaction. If industrial nitrogen is needed or environmental protection is needed, both gases need to be dechlorinated₄Can remove CH₄then separating, if the oxygen content in the incoming gas is lower, making high-purity H₂The second part of the gas can be directly subjected to a shift reaction; if the oxygen content in the incoming gas is relatively high, high purity H is produced₂The second part of the gas can be independently deoxidized and then subjected to shift reaction, and the deoxidizing step only considers the oxygen content, does not consider the hydrogen content, does not need to supplement trace oxygen, does not need to adjust the hydrogen-oxygen ratio, can reduce the amount of hydrogen reacted with oxygen, and is favorable for increasing the yield of hydrogen although a certain amount of hydrogen is consumed in the deoxidizing process. If the oxygen content in the incoming gas is higher, the two parts of gas need to be deoxidized and can be separated after dehydrogenation and deoxidation, and although the dehydrogenation and deoxidation carried out in one step can slightly increase the loss of hydrogen, the number of devices can be reduced, the occupied area can be reduced, and the investment and the operating cost can be reduced. In the removal of CO₂After separation, the gas can be made to contain a high content of undesirable CO₂Separated out to increase the content of useful gas, facilitate the subsequent pressurization operation and reduce the energy consumption of pressurizationHowever, subsequent shift reactions also produce CO₂And further needs to be performed again for CO removal₂。

After the second part of gas is shifted, the CO is contained in the gas₂、H₂And N₂Separating the reaction gas to obtain H₂In the meantime, by CO removal₂And N₂Wherein N is removed₂CO removal by pressure swing adsorption separation₂By pressure swing adsorption separation or absorption. . Specifically, after the shift reaction, the crude dehydration and the heavy component are carried out by a cooling liquid separating tank, the refined dehydration and the heavy component are carried out by a temperature swing adsorption method, and then the CO contained in the gas is removed by a pressure swing adsorption method₂Nitrogen and a trace amount of CO to obtain high-purity H meeting the preset requirement₂. If absorption method is adopted, CO is removed first₂After transformation, the raw material is firstly subjected to coarse dehydration and heavy component separation in a cooling liquid separation tank, then is decarbonized by an absorption method, and CO is removed by the absorption method₂The gas is subjected to temperature swing adsorption to remove water and heavy components, and then is subjected to pressure swing adsorption to remove nitrogen and trace CO contained in the gas₂CO to obtain high-purity H meeting the preset requirement₂(≧ 99.9%). High purity H₂And then the mixture is pressurized (the volume of the gas is the minimum and the pressurizing cost is the lowest) to be used as the raw material gas for synthesizing alcohol such as ethylene glycol.

in one embodiment, CO removal is included in both the first pretreatment stream and the second pretreatment stream₂And removing CO₂Adopting an absorption method and removing CO in the first impurity removal pretreatment₂The absorption liquid is sent to a second impurity removal pretreatment to remove CO₂As an absorption liquid. Twice CO removal₂The method adopts an absorption method and removes CO twice₂The same absorbent is used.

FIG. 1 shows a preferred process, in which a gas such as blast furnace gas is divided into two parts by desulfurization, demethanization, dehydrogenation and deoxidation in sequence, the first part of the gas is subjected to CO removal₂Then separating CO and N by pressure swing adsorption₂Obtaining CO; the second part of gas converts CO in the gas into H through conversion reaction₂To obtain CO-containing₂、H₂And N₂Removing CO from the reaction gas by pressure swing adsorption₂And N₂Separation to obtain H₂。

Correspondingly provided coal gas production H₂A plant for a/CO feed gas, as in figure 10, comprising:

The first pretreatment device is used for pretreating the gas feed gas and comprises a desulfurization device and a CH removal device which are sequentially connected₄Dehydrogenation and deoxidation device and CO removal of device₂A device; wherein one end of the flow dividing device is connected with an outlet of the dehydrogenation and deoxidation device, the other end of the flow dividing device is provided with a first part gas outlet and a second part gas outlet which are used for dividing the gas into two parts, and the first part gas outlet and the CO removal outlet are arranged₂The devices are connected.

Pressure swing adsorption apparatus and CO removal₂Connected with a device for separating CO and N from the first part of gas by a pressure swing adsorption method₂Obtaining CO; CO removal₂the pipeline between the device and the pressure swing adsorption device is preferably provided with a temperature swing adsorption device for removing water and heavy components. And a CO outlet of the pressure swing adsorption device is also connected with a CO storage tank, and the CO storage tank is connected with the ethylene glycol synthesis device.

A shift reactor connected to the second part gas outlet of the flow dividing device for performing shift reaction on the second part gas to convert CO in the gas into H₂To obtain CO-containing₂、H₂And N₂The reaction gas of (1).

H₂A separation unit connected to the shift reactor, the H₂The separation device is a second pressure swing adsorption device which directly absorbs CO₂、N₂Removing to obtain H₂. The line between the shift reactor and the second pressure swing adsorption unit is also preferably provided with a temperature swing adsorption unit. H₂H of the separation apparatus₂The outlet is also connected with a hydrogen storage tank, and the hydrogen storage tank is connected with an ethylene glycol synthesis device.

In the above-described processes, some separation steps require the use of pressure swing adsorption separation operations; the invention aims to solve the problem that in the process of large pressure change existing in the fields of normal-temperature pressure swing adsorption and non-normal-temperature pressure swing adsorption, the pressure of supplied gas is high or the supplied gas needs to be pressurized to be high so as to realize the separation effect meeting the requirement, in the process of frequent pressure increase and reduction operation, high pressure energy is carried in high-pressure gas discharged by equipment, and a large amount of energy loss exists in the process, so that an energy recovery device is added in the process of large pressure change to recover energy, and the recovered energy is used for providing mechanical energy for providing pressure for gas or liquid.

The equipment for discharging high-pressure gas is various in the industrial pressure swing adsorption equipment, most common is an adsorption tower, and can also be other pressure stabilizing tanks and buffer tanks, in these equipments the high-pressure gas is contained, and the pressure reducing process can be implemented by using another adsorption tower or pressure stabilizing tank or buffer tank which is in low-pressure state to make pressure equalizing, pressure charging, sequential discharge or reverse discharge, etc. in these processes, the high-pressure gas in adsorption saturated adsorption tower can be recovered by means of energy recovery device, and can be flowed into the adsorption tower or pressure stabilizing tank and buffer tank which are in low-pressure state, at the same time the energy recovery and normal pressure reducing process of pressure swing adsorption can be implemented, and when the energy recovery device adopts expansion machine, the pressure energy contained in high-pressure gas can be converted into mechanical energy, and these mechanical energies can be used for driving compressor to rotate, engine to generate electricity, Supplement the rotating output of the motor and the like. In the pressure swing adsorption process, the flow, pressure and pressure drop of the depressurization gas connected to the energy recovery device are unstable, and have periodicity and relatively large fluctuation, which generally results in that the energy recovery device can hardly work normally and stably, so that the energy recovery device needs to be improved correspondingly.

The main design concept of the invention is as follows: the expander can work normally by stabilizing the periodic rapid fluctuation of the gas discharged by the high-pressure device, mainly by stabilizing the fluctuation of the gas pressure at the gas inlet and/or gas outlet of the expander through a fluid buffer device; another solution idea is: smooth operation can be achieved by suppressing fluctuation in the rotational speed of the rotary shaft of the expander, and this can be achieved by installing a rotation resistance device on the rotary shaft.

Based on the above concept, there are several embodiments as follows:

The gas needing energy recovery is added into a buffer tank with a certain volume before entering a turbine expansion machine in the energy recovery device or after leaving the energy recovery device, the buffer tank can be used for stabilizing the fluctuation of the pressure and the flow of the pressurized gas so as to ensure that the pressurized gas is basically stable, and the expansion machine can recover the energy of the pressure swing adsorption medium gas and convert the energy into the mechanical energy of a shaft.

In another embodiment, a regulating valve is installed on a gas pipeline in the energy recovery device, and the fluctuation of the pressure and the flow rate of the high-pressure gas entering the expansion machine is restrained by correspondingly regulating the opening degree of the regulating valve according to the frequency and the magnitude of the pressure change in the process of the pressure change.

For designs requiring increased rotational resistance of the expander shaft, in another embodiment, a flywheel sized and distributed by mass is mounted on the expander shaft to increase the rotational inertia of the shaft, and the flywheel may be mounted on the shaft on the upstream or downstream side of the expander.

It can be seen from the above that, after the buffering device or the resistance device is used, when the expander converts the gas pressure energy into the mechanical energy, the change fluctuation of the energy can be better suppressed, so that the expander can normally and smoothly work, and the expander is also suitable for applying the mechanical energy to other processes needing energy consumption.

In order to better utilize the mechanical energy generated by the expansion machine, the mechanical energy can be used for driving other equipment to rotate and work, and the mechanical energy can also be converted into electric energy for reuse.

In one embodiment, when the expander drives the motor to generate power, the rotation of the expander has a certain periodic fluctuation change, so that the generated power is incorporated into a power grid, the power grid needs to have a large electric load capacity, and the power grid can stabilize the power with the periodic fluctuation change to realize utilization by utilizing the large capacity of the power grid for accommodating the current with the periodic rapid change; the electric energy in the power grid can be transmitted to other electric equipment, and can also drive a compressor in the pressure swing adsorption device to compress gas or liquid, so that the electric energy is recycled.

In pressure swing adsorption processes, there are processes in which a gas is periodically pressurized. Therefore, in another embodiment, the electric energy generated by the expander driving the motor can be used for driving the compressor by the motor to work, and the pressurization operation of the gas or the liquid is completed, so that the electric energy can be recycled.

since overload may adversely affect equipment adequacy, stability, life, and safety during operation of a motor coupled to a compressor, in one embodiment, the motor may be coupled to a capacitor bank or battery pack that can rapidly stabilize current rapid changes when current fluctuations are large, thereby enhancing the response of the motor system to the rotational energy required to rapidly change the shaft.

The above description is about the embodiment of converting the mechanical energy generated by the expander into electric energy, and the mechanical energy generated by the expander can be directly used. In such embodiments, the expander, motor, compressor or pump comprises an energy recovery device that may or may not comprise a coaxial drive system. The coaxial driving system is formed by directly supplementing the mechanical energy converted by the expansion machine on a shaft system of a compressor or a pump, and meanwhile, the insufficient part is supplemented by energy provided by the motor, for example, the motor is connected in a larger power grid, on one hand, the motor is driven to operate by electric energy, and meanwhile, the rotating shaft of the motor is also linked with the rotating shaft of the expansion machine, so that the effect that the expansion machine supplements the mechanical energy on the motor is realized, and the mechanical energy obtained by the expansion machine can be directly utilized in the mode, and the fluctuation of the mechanical energy can be stabilized by the combined action of the expansion machine and the motor. The coaxial driving system has the advantages of compact structure, high overall efficiency, low overall equipment cost and operation cost, and good economic benefit.

For pressure swing adsorption processes, there is typically a high pressure device (e.g., a higher pressure adsorption column) delivering high pressure gas to a low pressure device (e.g., a lower pressure adsorption column) such that the pressure in the high pressure column is reduced and the pressure in the low pressure column is increased, which may be a pressure change between two gas buffer tanks or a pressure change between an adsorption column and a buffer tank. When the fluid buffer device and the expander are used as the energy recovery device of the main body, the phenomenon that the temperature of gas is reduced after the gas flows from the high-pressure side to the low-pressure side through the expander can be realized, because the energy recovery process is an expansion process of reducing pressure and outputting work to the outside, the temperature of the gas at the outlet of the expander can be reduced, when low-temperature gas enters into another tower needing pressurization, the adsorption temperature can be reduced, so that the adsorption temperature of the adsorption tower is lower than the desorption regeneration temperature, the low adsorption temperature is favorable for increasing the adsorption amount of a unit adsorbent, the high desorption regeneration temperature is favorable for leading the desorption of the adsorbent to be more thorough, and the dynamic adsorption amount of the adsorbent is increased. The gas at the outlet of the expansion machine can also be used for outputting cold energy with certain temperature to other devices through the heat exchanger.

In addition, by adding fluid buffer devices in front of and behind the expansion machine, the gas pressure can be effectively prevented from periodically and rapidly changing; the over-large and frequent impact load can lead the adsorbent to be easily pulverized, reduce the service life of the adsorbent and simultaneously have adverse effects on the safety and the fatigue service life of the adsorption tower, so that equipment with a control valve, a buffer tank and the like is used in the pressure swing adsorption device to inhibit the rapid fluctuation of high-pressure gas, prolong the service life of the adsorbent and simultaneously be beneficial to the safety and the fatigue service life of the adsorption tower.

Based on the operation of the energy recovery device described above, a typical pressure swing adsorption process of the present invention is as follows:

one of the more common pressure swing adsorption industrial processes is as follows:

Step 1, introducing the mixed gas from the upstream into an adsorption tower in an adsorption stage, adsorbing most of easily-adsorbed components by an adsorbent in the adsorption tower, and allowing most of difficultly-adsorbed components to pass through a bed layer of the adsorption tower to form the adsorption stage.

And step 2, reducing the pressure of the adsorption tower in adsorption saturation obtained in the step 1, wherein the pressure reduction process can be a process of carrying out pressure equalization, sequential discharge or reverse discharge with another adsorption tower in a low-pressure state or a pressure stabilizing tank and a buffer tank. In the processes, the high-pressure gas in the adsorption saturation adsorption tower recovers the recoverable energy through the energy recovery device and then flows to the adsorption tower or the pressure stabilizing tank and the buffer tank in a low-pressure state. And the energy recovery and the normal pressure-swing adsorption depressurization process are simultaneously completed.

And 3, possibly depressurizing the depressurized gas in the adsorption tower, the pressure stabilizing tank, the buffer tank and the like obtained in the step 2 again or depressurizing the depressurized gas again after certain treatment (such as replacement or re-adsorption, pressurized flushing, pressurization and the like). Also this process may require similar processing as step 2. The process may be pressure equalizing, sequential or reverse releasing with one other adsorption tower, pressure stabilizing tank, buffering tank, etc. In the processes, the high-pressure gas in the adsorption saturation adsorption tower recovers the recoverable energy through the energy recovery device and then flows to the adsorption tower or the pressure stabilizing tank and the buffer tank in a low-pressure state. And the energy recovery and the normal pressure-swing adsorption depressurization process are simultaneously completed.

Step 4, and possibly a similar process of step 2 or step 3, is repeated until the pressure in the adsorption column is sufficiently low.

and 5, carrying out a desorption and regeneration process under a low pressure state on the adsorption tower reduced to the low pressure state in the step 4, wherein methods such as vacuumizing, purging or vacuumizing plus purging or low-pressure desorption can be adopted in the process.

And step 6, carrying out pressure equalizing and boosting processes on the adsorption tower subjected to low-pressure desorption by other adsorption towers or pressure stabilizing tanks and buffer tanks in the step 3, wherein high-pressure gas subjected to energy recovery and pressure reduction in the step 2 or the step 3 can be received in the pressure equalizing and boosting processes.

And step 7, boosting the pressure of the gas obtained in the step 6 after the pressure is increased in the adsorption tower, the pressure stabilizing tank, the buffer tank and the like again or boosting the pressure of the gas after the pressure is increased after certain treatment (such as replacement or re-adsorption, under-pressure flushing, pressure charging and the like) is carried out again, and the high-pressure gas after the pressure is reduced after the energy recovery in the step 2 or the step 3 can be received in the possible boosting processes.

In step 8, there may be a need to increase the pressure of the adsorption column in step 7 to a pressure close to the pressure of the adsorption step again using the raw material gas or the non-adsorbed gas adsorbed by the adsorption column.

And 9, the processes of the first step 8 are carried out for the single tower to continuously operate in a circulating reciprocating way, and for the towers to be matched with each other and alternately to continuously operate in a circulating reciprocating way.

The processes of high-pressure adsorption, pressure-reducing energy recovery, pressure reduction, low-pressure desorption and the like carry out continuous operation of circulating reciprocation on a single tower, and carry out continuous operation of circulating reciprocation on the towers which are matched with each other and staggered.

The periodic rapid change pressure energy in the pressure swing adsorption separation process is recovered and converted into the conventional available mechanical energy for supplying to the gas pressurization process, so that the electric energy consumed by gas pressurization is saved. Compared to a pressure swing adsorption system without an added energy recovery device, it can recover 50% of the energy loss due to the pressure difference in the conventional pressure swing adsorption system.

In addition, the non-adsorption gas after adsorption in the adsorption process can have higher pressure, or the gas is discharged or the gas with the high pressure is not needed at the demand end, the high-pressure gas can be connected into a device for recovering and pressurizing the coupling device for energy recovery, and the gas with the reduced pressure after energy recovery is connected into the demand end or is discharged again.

In the present invention, the adsorbent used in the adsorption process may be any type of adsorbent having an adsorption effect, and is not particularly limited, and may be molecular sieve, activated carbon, carbon molecular sieve, activated alumina, carbon fiber, etc., and mixed packing and layered packing thereof.

The present invention is further illustrated by the following specific examples, and unless otherwise specified, the methods, adsorbents or catalysts used in the examples may be performed by any means conventional in the art.

Example 1

The blast furnace gas incoming material is dedusted, desulfurized by a desulfurizer consisting of iron oxide, manganese oxide and ZnO at 380 ℃ and 0.36MPa, subjected to methane catalytic combustion reaction at 300 ℃ and 0.36MPa along with the reduction of temperature, and subjected to catalytic reaction under the conditions that the temperature is reduced to 220 ℃ and the pressure is kept unchanged and is still 0.36MPa after removing trace methane, so that trace hydrogen and oxygen in the blast furnace gas are removed. The resulting gas is split into two main portions.

The first part of the obtained gas with about 1/3 volume is further sent into a temperature swing adsorption device under the conditions that the temperature is reduced to 32 ℃ and the pressure is kept unchanged and still is 0.36MPa to remove trace moisture and components such as heavy components contained in the gas, and then sent into a pressure swing adsorption decarbonization device (0.36MPa, 32 ℃) to remove carbon dioxide, and the removed carbon dioxide is treated to reach the emission standard and then is discharged. The gas component now contains mainly CO and nitrogen. The partial gas is sent into a pressure swing adsorption CO and nitrogen separation device (or called pressure swing adsorption device) to separate CO and nitrogen, industrial grade nitrogen (the volume composition is more than or equal to 99.2 percent) is extracted under the conditions that the adsorption pressure is 0.35MPa and the operation temperature is 32 ℃, and the industrial grade nitrogen is sent to a nitrogen recovery system as a product. And (3) sending the high-purity CO product obtained by vacuum-pumping desorption at the bottom of the pressure swing adsorption tower into a compressor unit for pressurization, and after the high-purity CO product enters an intermediate gas storage tank to 0.35MPa, taking the high-purity CO product as a raw material gas for synthesizing the ethylene glycol for a device for synthesizing the ethylene glycol in the next step.

And mixing the other part of the obtained gas with the volume of about 2/3 with saturated steam under the pressure condition of 0.36MPa, then entering a multi-stage adiabatic shift reactor for shift reaction, adopting intermediate-stage water chilling to remove reaction heat, wherein the reaction temperature is 180-350 ℃, and cooling water is heated and then enters a waste heat boiler. Cooling the gas after the shift reaction to be lower than 100 ℃ through a gas-liquid separation tank, liquefying the water vapor, carrying out gas-liquid separation to remove liquid water, cooling to 32 ℃, and removing trace components such as water and heavy components through a temperature swing adsorption method; then the mixture is introduced into a pressure swing adsorption hydrogen extraction device which mainly removes carbon dioxide and nitrogen generated by the shift reaction. And finally, pressurizing the purified hydrogen to 3.0MPa, and then feeding the hydrogen into an intermediate gas storage tank to be used as raw material gas for synthesizing the ethylene glycol for a next device for synthesizing the ethylene glycol.

In the process and the reaction flow of the embodiment, not only the raw material gas for synthesizing the ethylene glycol is obtained, but also the industrial-grade nitrogen is recovered, and a small amount of methane contained in the blast furnace gas is subjected to catalytic combustion reaction treatment in a high-temperature working section, so that the environmental protection index is better guaranteed.

Example 1 the detailed process flow is shown in fig. 2, and the gas composition during each step is shown in table 1.

TABLE 1

Example 2

Converter gas raw material (0.12MPa, 380 ℃) is dedusted, and then is subjected to catalytic hydrogenation conversion to convert sulfur in the gas into hydrogen sulfide (0.2MPa, 300 ℃) which is easy to remove, so that the obtained gas is mainly divided into two parts.

The first part of the obtained gas with the volume of about 1/3 is pressurized to 0.4MPa, and the gas further enters a carbon dioxide absorption tower after the temperature is reduced to 40 ℃, the carbon dioxide absorption tower adopts a DEA absorption method, the carbon dioxide absorption tower adopts DEA solution as an absorbent to remove carbon dioxide and most of trace sulfur in the absorption tower, the absorbed and saturated DEA solution is heated in a regeneration tower to release carbon dioxide and trace sulfur for activation and other impurity regeneration, and the removed carbon dioxide is treated to reach the standard and then is recycled by other devices. The gas after carbon dioxide removal is sent into a temperature swing adsorption device, temperature swing adsorption separation is carried out under the conditions that the adsorption pressure is 0.2MPa and the operation temperature is 32 ℃, then water and other heavy component components are removed, and then fine desulfurization is carried out through a fine desulfurization adsorption tower consisting of active carbon, a molecular sieve and metal oxides of iron, manganese, zinc and the like, wherein the gas components mainly contain CO and nitrogen. The partial gas is sent into a pressure swing adsorption CO and nitrogen separation device to separate CO and nitrogen, the CO gas is purified by a pressure swing adsorption separation method under the conditions of similar adsorption pressure and adsorption temperature (0.2MPa, 32 ℃), the purity of the obtained CO gas is more than or equal to 99 percent, and the gas which is separated from the top of the pressure swing adsorption tower and contains a large amount of nitrogen is discharged after being processed after the residual pressure recovery device recovers the contained pressure energy and reaches the discharge standard. And (3) sending a high-purity CO product obtained by vacuum-pumping desorption at the bottom of the pressure swing adsorption tower into a compressor unit for pressurization, carrying out catalytic reaction at the temperature of 140 ℃ after the pressure is 0.35MPa, removing trace hydrogen and oxygen in the product, sending the product into an intermediate gas storage tank, and using the product as a raw material gas for synthesizing the ethylene glycol for a next device for synthesizing the ethylene glycol.

And desulfurizing the other part of the obtained gas with about 2/3 volume by using a desulfurizing agent consisting of iron oxide, manganese oxide and ZnO at 320 ℃, further mixing the obtained gas with saturated steam and partial cis-gas generated in the process of separating CO and nitrogen in a pressurized pressure swing adsorption CO and nitrogen separation device under the conditions of reducing the temperature to 200 ℃ and pressurizing to 0.4MPa, then introducing the mixture into a multi-section adiabatic shift reactor for shift reaction, adopting intermediate-stage water chilling to remove reaction heat release, wherein the reaction temperature is 180-500 ℃, and cooling water is heated and then sent to a waste heat boiler. Cooling the gas after the shift reaction to be lower than 100 ℃ through a gas-liquid separation tank, liquefying the water vapor, carrying out gas-liquid separation to remove liquid water, cooling to 32 ℃, and removing trace components such as water and heavy components through a temperature swing adsorption method; then the mixture is introduced into a pressure swing adsorption hydrogen extraction device (0.39MPa, 32 ℃), and carbon dioxide, nitrogen and other impurity components generated by the shift reaction are mainly removed. And finally, pressurizing the purified hydrogen to 3.5MPa, and then feeding the hydrogen into an intermediate gas storage tank to be used as raw material gas for synthesizing the ethylene glycol for a next device for synthesizing the ethylene glycol. The method recovers CO contained in the process gas by introducing the process gas such as the replacement tail gas, partial cis-release gas and the like in the pressure swing adsorption CO and nitrogen separation device, fully utilizes useful gas and reduces the waste of effective gas; meanwhile, due to the introduction of process gases such as the displacement tail gas, partial cis-bleed gas and the like, the concentration of CO in the gas is reduced, the conversion depth is reduced, the exothermic temperature rise of the reaction is reduced, the maximum use temperature of the catalyst is reduced, the severity of conversion conditions is reduced, and the service life of the conversion catalyst is prolonged.

In the process and reaction scheme of this example, the raw material gas for synthesizing ethylene glycol is mainly considered to be the DEA absorption method instead of the pressure swing adsorption method mentioned in example 1 for removing CO₂Meanwhile, the method simplifies and adjusts the partial purification process without recovering industrial nitrogen, simplifies the steps, shortens the flow, saves the cost, and simultaneously recovers the pressure energy contained in the emptied gas by using a residual pressure recovery system. The method comprehensively balances the service life of the shift catalyst, and simultaneously links and recycles the process gases of the tail gas replacement, partial downstream gas release and the like of another set of device, so that the useful gases are fully utilized, and the waste of effective gases is reduced.

Example 2 the detailed process flow is shown in fig. 3, and the gas composition during each step is shown in table 2.

TABLE 2

Example 3

blast furnace gas incoming materials (350 ℃, 0.2MPa) are dedusted, and are desulfurized by a desulfurizer consisting of manganese oxide and ZnO at 350 ℃ and 0.2MPa, so that the obtained gas is mainly divided into two parts.

The first part of the obtained gas with about 1/3 volume undergoes methane catalytic combustion reaction at 290 ℃ and 0.2MPa along with the reduction of the temperature, and after trace methane is removed, the catalytic reaction is further carried out under the conditions that the temperature is reduced to 200 ℃ and the pressure is kept unchanged and still remains at 0.2MPa, so that trace hydrogen and oxygen in the blast furnace gas are removed. The treated gas enters a gas compressor unit to be pressurized to 0.45MPa, the temperature is reduced to 40 ℃, and then the gas enters a carbon dioxide absorption tower, the carbon dioxide absorption tower adopts an active MDEA absorption method, the carbon dioxide absorption tower adopts an active MDEA solution as an absorbent to remove carbon dioxide and trace sulfur in the absorption tower, and the absorbed active MDEA solution is discharged from the tower, pressurized and sent to an absorption tower of a decarbonization device of the second part and taken as absorption liquid to be absorbed and decarbonized again. The removed carbon dioxide is treated and then reaches the standard and then is recycled by other devices. And sending the part of gas into a temperature swing adsorption device, and carrying out temperature swing adsorption separation under the conditions that the adsorption pressure is 0.35MPa and the operation temperature is 32 ℃ so as to remove water and other heavy component components, wherein the gas components mainly contain CO and nitrogen. The partial gas is sent into a pressure swing adsorption CO and nitrogen separation device for separating CO and nitrogen, industrial nitrogen (the volume composition is more than or equal to 99.2 percent) is extracted under the conditions that the adsorption pressure is 0.35MPa and the operation temperature is 32 ℃, and the industrial nitrogen is sent to a nitrogen recovery system as a product. And (3) sending the high-purity CO product obtained by vacuum-pumping desorption at the bottom of the pressure swing adsorption tower into a compressor unit for pressurization, and after the pressure is increased to 0.35MPa, sending the product into an intermediate gas storage tank to serve as a raw material gas for synthesizing the ethylene glycol for a device for synthesizing the ethylene glycol in the next step.

And the second part of the obtained gas with the volume of about 2/3 is further subjected to catalytic reaction under the conditions that the temperature is reduced to 200 ℃ and the pressure is kept unchanged and still is 0.2MPa, trace oxygen in the blast furnace gas is removed, the blast furnace gas is pressurized to 0.45MPa and mixed with steam, the mixture enters a multi-section adiabatic shift reactor for shift reaction, intermediate-stage water chilling is adopted to remove reaction heat release, the reaction temperature is 180-450 ℃, and cooling water is heated and then enters a waste heat boiler. Cooling the gas after the shift reaction to be lower than 100 ℃ through a gas-liquid separation tank, liquefying water vapor, then carrying out gas-liquid separation to remove liquid water, cooling to 40 ℃ and then entering a carbon dioxide absorption tower, wherein the carbon dioxide absorption tower adopts an active MDEA absorption method, the carbon dioxide absorption tower adopts an active MDEA solution as an absorbent to remove carbon dioxide in the absorption tower, and the carbon dioxide absorption tower adopts an active MDEA solution mainly from an absorption tower of a first part of decarburization (carbon dioxide removal) device as an absorption liquid to carry out absorption decarburization again; the absorption tower also has part of absorption liquid from the lean liquid after heat regeneration and the semi-lean liquid after decompression regeneration. The active MDEA solution after saturated absorption is subjected to decompression regeneration to release part of contained carbon dioxide, and part of the active MDEA solution subjected to decompression activation regeneration is used as a semi-barren solution and sent to an absorption tower to remove the carbon dioxide; heating the rest part of the active MDEA solution in a thermal regeneration tower for regeneration to release the rest part of the contained carbon dioxide, and then activating and regenerating the residual part of the carbon dioxide, and finally completely activating and regenerating the residual part of the carbon dioxide into barren liquor; and (4) processing the removed carbon dioxide, and then emptying the carbon dioxide after the carbon dioxide reaches the emission standard. Then, removing trace moisture and heavy components contained in trace absorption liquid carried out in the gas by the temperature swing adsorption device under the conditions that the adsorption pressure of the gas subjected to the active MDEA solution decarburization is 0.35MPa and the operation temperature is 32 ℃, wherein the gas mainly contains hydrogen and nitrogen; then the mixture is introduced into a pressure swing adsorption hydrogen extraction device (0.35MPa, 32 ℃), and the nitrogen contained in the mixture is mainly removed. And finally, pressurizing the purified hydrogen to 2.8MPa, and then feeding the hydrogen into an intermediate gas storage tank to be used as raw material gas for synthesizing the ethylene glycol for a next device for synthesizing the ethylene glycol.

Preparation of H under the Process and reaction scheme of this example₂The MDEA absorption method with the addition of the activating agent is mainly considered for the CO raw material gas and is divided into two times of high and low different CO₂Removal of CO at a concentration of₂twice CO removal₂The method adopts an absorption method and removes CO twice₂The same absorbent is used. First CO removal by absorbent₂In the process of (2) at a low CO₂The absorption tower at the concentration absorbs a certain amount of CO₂Then the mixture enters a second CO removal step after being pressurized₂In the process of (2) at a higher CO₂The absorption tower at the concentration continuously absorbs CO₂And then, after the absorption is finished, the mixture enters a regeneration tower to finish the activation and regeneration process. Due to the first CO removal₂Operating at a lower CO₂Absorbing absorption liquid under the concentration condition, wherein the absorption liquid generally does not realize saturated adsorption, and CO obtained after CO conversion₂the concentration is higher, and the absorption liquid can further absorb CO₂The method is favorable for reducing the circulation amount of the absorption liquid so as to reduce the circulation amount of the regeneration liquid, thereby being favorable for reducing the regeneration flow and saving the regeneration energy; with similar effect, also including the use of the same absorption liquidThe pressure of at least two towers entering successively has a certain difference from a certain difference or the pressure and the concentration have a certain difference at the same time; the method also recovers industrial nitrogen, and a small amount of methane contained in the blast furnace gas is subjected to catalytic combustion reaction treatment in a high-temperature section, so that environmental protection indexes are guaranteed.

Example 3 the detailed process flow is shown in fig. 4, and the gas composition during each step is shown in table 3.

TABLE 3

Comparative example 1

The differences from example 1 are: dehydrogenation and deoxidation are carried out at the later stage of the process, the first part of gas is PSA separated into CO and nitrogen to obtain pure CO, and then catalytic dehydrogenation is carried out₂And O₂. The second portion of the gas is not dehydrodeoxygenated. The specific process is as follows:

The blast furnace gas coming material is dedusted, desulfurized by a desulfurizer consisting of iron, manganese oxides and ZnO at 380 ℃ and 0.36MPa, and subjected to methane catalytic combustion reaction at 300 ℃ and 0.36MPa along with the reduction of temperature to remove trace methane. The resulting gas is split into two main portions.

The first part of the obtained gas with about 1/3 volume is further sent into a temperature swing adsorption device to remove trace moisture and components such as heavy components contained in the gas under the conditions that the temperature is reduced to 32 ℃ and the pressure is kept unchanged and still is 0.36MPa, and then sent into a pressure swing adsorption decarbonization device to remove carbon dioxide, and the removed carbon dioxide is discharged after being treated to reach the discharge standard. The gas component now contains mainly CO and nitrogen. And (3) sending the part of gas into a pressure swing adsorption CO and nitrogen separation device for separating CO and nitrogen, wherein the volume composition of the extracted nitrogen is less than or equal to 99.2 percent under the conditions that the adsorption pressure is 0.35MPa and the operation temperature is 32 ℃, the requirement of industrial nitrogen cannot be met, the part of gas can only be sent to an energy recovery system, and the gas is discharged after the pressure energy of the nitrogen is recovered. The volume composition of CO is less than or equal to 99 percent, the preset requirement can not be met, and the CO can not be used as raw material gas for synthesizing the ethylene glycolThe device for synthesizing the ethylene glycol in one step is used. And over time the adsorbent begins to deteriorate and over a period of one month the adsorbent has not reached the separation requirement. And (3) feeding the CO product obtained by vacuum-pumping desorption at the bottom of the pressure swing adsorption tower into a compressor unit for pressurization, feeding the CO product into an intermediate gas storage tank until the pressure reaches 0.35MPa, then heating the CO product to 140 ℃, and carrying out catalytic reaction under the condition that the pressure is kept unchanged and still reaches 0.35MPa to remove trace hydrogen and oxygen contained in the CO gas. By catalytic dehydrogenation of H₂And O₂The pure CO is used as raw material gas for synthesizing the ethylene glycol and is used by a device for synthesizing the ethylene glycol in the next step, and because the catalytic dehydrogenation is carried out in the pure CO₂Due to the extremely high CO content, the H is removed₂And O₂To H₂≤100ppm，O₂1000ppm or less, and more CO and O due to the high CO concentration₂The reaction causes waste of CO, and H is generated after the reaction₂O and CO₂In order to remove the impurities which are used as the catalyst and do not influence the following reaction, another temperature swing adsorption purification device is additionally arranged to remove the impurities subjected to catalytic dehydrogenation₂and O₂Impurities resulting from the reaction.

And mixing the other part of the obtained gas with the volume of about 2/3 with steam under the pressure condition of 0.36MPa, then entering a multi-stage adiabatic shift reactor for shift reaction, adopting intermediate-stage water chilling to remove reaction heat release, wherein the reaction temperature is 180-350 ℃, and cooling water is heated and then sent to a waste heat boiler. Cooling the gas after the shift reaction to be lower than 100 ℃ through a gas-liquid separation tank, liquefying the water vapor, carrying out gas-liquid separation to remove liquid water, cooling to 32 ℃, and removing trace components such as water and heavy components through a temperature swing adsorption method; then the mixture is introduced into a pressure swing adsorption hydrogen extraction device which mainly removes carbon dioxide and nitrogen generated by the shift reaction. And finally, pressurizing the purified hydrogen to 3.0MPa, and then feeding the hydrogen into an intermediate gas storage tank to be used as raw material gas for synthesizing the ethylene glycol for a next device for synthesizing the ethylene glycol. And as time goes on, the shift catalyst begins to deteriorate, the shift effect of the quasi-isothermal shift reactor becomes worse and worse after 6 months, the CO concentration in the outlet of the shift reactor adopting different schemes is shown in table 5 along with the working time, it can be seen that the purity of the hydrogen after the shift by adopting the comparative scheme is lower and lower along with the time, and the content of CO in the generated purified tail gas is higher and higher through the pressure swing adsorption decarburization hydrogen extraction device, which causes unnecessary waste of raw materials and is not beneficial to environmental protection.

The content of the raw material gas for synthesizing ethylene glycol obtained by the process and the reaction flow of the embodiment cannot meet the preset requirement, and cannot meet the industrial grade nitrogen, and the adsorbent is poisoned, so that the adsorbent begins to deteriorate until the adsorbent cannot be used with the passage of time. Due to the catalytic removal of H in pure CO₂And O₂Will make more CO and O₂The waste of CO is caused by the reaction, and the reaction product after catalytic dehydrogenation and deoxidation is taken as an impurity and needs to be removed, so that a corresponding impurity removal step and a corresponding impurity removal device need to be added. And because the transformation catalyst agent is deteriorated due to the overhigh content of oxygen, the transformation effect of the transformation reactor is poorer and poorer, the purity of the transformed hydrogen is lower and lower, the content of CO in the generated purified tail gas is higher and higher, the unnecessary waste of raw materials is caused, and the environment is not facilitated.

The detailed process flow of comparative example 1 is shown in FIG. 5, and the gas composition during each step is shown in Table 4.

TABLE 4

TABLE 5

	1 day	30 days	60 days	90 days	120 days	150 days	180 days
								Example 1 protocol inlet CO concentration%	23.23	23.23	23.23	23.23	23.23	23.23	23.23
Example 1 protocol Change Outlet CO concentration%	0.07	0.07	0.07	0.07	0.07	0.07	0.07
								Comparative example protocol inlet gas CO concentration%	22.57	22.57	22.57	22.57	22.57	22.57	22.57
Comparative example protocol shifted outlet CO concentration%	0.07	0.07	0.1	0.18	0.3	0.6	1

As can be seen from Table 5, dehydrogenation-first deoxidation and CO removal are employed₂The method has low CO concentration in the gas, is beneficial to improving the selectivity of catalytic oxidative dehydrogenation and reducing the reaction of CO and oxygen, thereby reducing CO waste, ensuring that the reaction condition is not so harsh and being beneficial to the selection of the catalyst. Meanwhile, the content of oxygen in the gas is reduced, which is beneficial to protecting the adsorbent in the step of CO and nitrogen and the catalyst of the shift reaction, and the step and the device for removing the reaction product as the impurity after dehydrogenation and deoxidation are reduced.

Example 4 this example illustrates the energy recovery process in a two column pressure swing adsorption

Some tail gas also contains trace N₂、CO、CO₂、CH₄And Ar and other impurities, and a hydrogen separation unit is required to be arranged for separation and purification in order to meet the requirement of the product hydrogen. Due to the movement of upstream devices

The higher line pressure causes the higher pressure of the raw material gas entering the pressure swing adsorption separation device of H2, and the H after the separation needs to be completed₂Pressurization to 4.2MPa (G) is required.

The raw material gas condition is as follows:

Component (Dry basis)

CO

H₂

CO₂

N₂

Ar

CH₄

H₂S+COS

Vol，％

11.179

68.28

10.004

10.227

0.003

0.308

0.1ppm

Flow rate: 2000Nm³H (dry basis)

Pressure: 2.2MPa (G)

Temperature: about 32 DEG C

Total H₂O、O₂、NH₃、CH₃OH, chlorine, phosphorus, arsenic, fluorine, HCN: less than or equal to 0.1ppm

Is filled with H₂The pressure swing adsorption purification device for separating the special adsorbent is used for separating and purifying, and the separation step comprises the following steps: adsorption, pressure equalizing and reducing, reverse pressure releasing, vacuumizing, pressure equalizing and increasing and final pressure charging. The method comprises the following steps of: energy is recovered by adopting an energy recovery and pressurization coupled device in voltage equalizing, reverse voltage releasing and final voltage boosting, and H is completed simultaneously₂is especially effective in removingAnd (4) transforming.

The energy recovery and pressurization coupling device is a system consisting of a screw expander, a compressor and a motor, a capacitor bank, an adjusting valve bank, a flywheel and a plurality of buffer tanks which have auxiliary functions, and also comprises a speed change mechanism, a control system and other complex systems. In the presence of pressurized H₂Buffer tanks of a certain volume are added before entering the energy recovery device and after leaving the energy recovery device to stabilize the pressurized H₂To make it substantially stable.

The apparatus provided in this embodiment is shown in fig. 6, 7 and 8, in which the exhaust pipe of the adsorption tower 1A is connected to the first stage 2 of the expander, the exhaust direction of the first stage 2 of the expander is further connected to the adsorption tower 1B, buffer tanks 13 and 14 are respectively connected to the pipes at the inlet and outlet sides of the first stage 2 of the expander, the rotating shaft of the first stage 2 of the expander is further connected to the motor 4, the motor 4 is further connected to the compressor 3 for pressurizing the gas, a compressed gas inlet buffer tank 11 and a compressed gas outlet buffer tank 12 are respectively provided at the inlet and outlet of the compressor 3, and the motor 2 is further connected to the capacitor bank 10.

The operation of the device is further described below in connection with its operation:

In the process of adsorbing in the adsorption tower 1A (hereinafter referred to as tower A) within the time period of 0-3 min, opening a valve A5A1, and allowing feed gas to enter the adsorption tower A in a state to be adsorbed through a feed gas pressure stabilizing tank (18) and an adjusting valve E4; the gas which is not adsorbed at the tower top passes through a product gas pressure stabilizing tank (19) and a regulating valve E3 to be used as the product gas for other devices. The adsorption tower 1B (hereinafter referred to as tower B) is vacuumized, the valve B6 is opened, and the tower B is vacuumized by the reciprocating pump (6) through the evacuation gas buffer tank (5). The energy recovery device does not pass through gas, and the energy is not recovered and is supplied to a compressor (3) for gas compression.

The pressure equalizing process of the tower A and the tower B is carried out in a (3-4 min) time period, the valve A2B3E2 is opened, the tower B is pressurized by utilizing high-pressure gas in the tower A, firstly, pressure in a pipeline, pressure difference of an inlet and an outlet of an expansion machine (3) and flow change are large at the moment of opening the valve A2B3E2, so that larger impact load can be caused, and the stable and safe operation of equipment and the service life of the equipment can be influenced by the overlarge impact load. Therefore, the pressure difference and the flow rate of the inlet and the outlet of the expansion machine 3 are adjusted by the adjusting valve E5E10, and at the moment when the valve A2B3E2 is opened, the opening degree of the adjusting valve E5E10 is reduced, so that the pressure of the corresponding adsorption tower is suppressed, and the influence of impact load on the expansion machine is reduced. The buffer tanks (13) and (14) connected with the pipelines of the inlet and the outlet of the expander are used for buffering, when the pressure in the pipeline connected with the buffer tanks is higher than the pressure set by the valve E6E7, the valve E6E7 is opened, the buffer tanks are communicated with the pipelines, gas is enabled to flow separately into the buffer tanks, the amount of the gas entering the expander is reduced, the influence of impact load is reduced, the time required for the action of the adjusting mechanism of the expander is obtained, the adjusting and controlling mechanism is enabled to act the slide valve of the screw expander, and the flow rate, the internal pressure ratio and the internal volume ratio of the flow passing through the expander can be suitable for the external pressure ratio and the flow rate of the inlet and the outlet of the expander after the. Meanwhile, the pressure energy acting on the expansion machine drives the shaft to rotate and is converted into mechanical energy of the shaft, the rotating speed of the shaft is easy to exceed the set required rotating speed due to impact load formed in the valve opening process, the change of the rotating speed of the shaft is not beneficial to forming resultant force with the motor to jointly drive the compressor to complete the compression process of another gas, and the rotating inertia of the shaft is increased by adding the flywheel with certain size and certain mass distribution on the rotating shaft, so that the acceleration obtained by the rotating shaft is reduced under the same torque, and the rotating speed of the rotating shaft is favorably stabilized at the set required rotating speed. The rotating shaft of the expansion machine is connected with the motor (4) and can drive the motor to rotate, but the rotating speed of mechanical energy output by the expansion machine can cause periodic change due to the frequent change process of pressure swing adsorption, so that the operation of the motor is unstable, and therefore the current required by the motor needs to be connected into the whole power grid, the large power grid is used for accommodating the current which changes periodically and rapidly, and the control device is used for finishing the stable driving of the motor. Under the action of impact load, the flow of current input by the motor by a power grid can be rapidly reduced, even the transmission direction of the current is changed, so that the rapid change of the flow of the current caused under the action of the impact load is stabilized by connecting the motor with the capacitor bank (10), the response capability of a motor system to the rotation energy required by the rapidly-changing rotating shaft can be enhanced, and the impact on the power grid is reduced. Along with the increase of the operation time, the gas in the tower A gradually flows to the tower B, the pressure of the tower A is gradually reduced, the pressure of the tower B is gradually increased, the pressure difference between the two towers is gradually reduced, the pressure difference of the gas between the inlet and the outlet of the expansion machine is gradually reduced, the flow rate is also gradually reduced, and the process is gradually changed. The opening degree of the regulating valve E5E10 is adjusted larger, reducing the resistance loss at the valve. When the pressure in the pipeline at the inlet and the outlet of the expander is gradually changed, the gas is gradually changed from the inflow buffer tank to the outflow buffer tank, and when the pressure in the pipeline connected with the buffer tank is lower than the pressure set by the valve E6E7, the valve E6E7 is closed, and the buffer tank is not communicated with the pipeline. The compressed gas needs basically stable pressure and flow, which means that the shaft power needed by the compressed gas needs to be basically stable, so that the compressed gas is connected to the buffer tank at the inlet and the outlet of the compressor to cope with possible pressure and flow fluctuation, the pressure difference of the gas between the inlet and the outlet of the expander is gradually reduced along with the change of time, the flow is also gradually reduced, the shaft power output by the expander is also gradually reduced, the shaft power output by the motor needs to be gradually increased, and the current input by a power grid needs to be adjusted to be gradually increased through the control system to supplement the shaft power needed by the compressed gas. The current required by the motor needs to be connected into the whole power grid, and the stable driving of the motor is completed by using the capacity of the large power grid for the current which changes periodically and rapidly and applying a control device. Meanwhile, the slide valve of the screw expander is adjusted through the adjusting control mechanism, and the flow, the internal pressure ratio and the internal volume ratio of the expander are adjusted, so that the expander keeps high efficiency.

Because the energy recovery process is an expansion process of reducing pressure and outputting work to the outside, the temperature of the gas at the outlet of the expansion machine is reduced, the temperature reduction amplitude is determined by the pressure difference between the inlet and the outlet of the expansion machine, and the gas at the outlet of the expansion machine outputs cold energy with certain temperature to the outside through the heat exchangers (20) and (21) for other devices to use. The gas at the outlet of the expander enters the tower B, the pressure equalizing and boosting process is carried out on the tower B, the temperature of the gas after certain cold energy is recovered through heat exchange is lower than that of the gas at the inlet end of the expander, and the temperature of the tower B is reduced through the entrance of low-temperature gas. To B tower, the entering that has similar low-temperature gas equally in the pressurization process of next step makes the process that the temperature of B tower reduces, can make B tower in the step that next step adsorbs, the adsorption temperature of B tower can reduce, the adsorption temperature that can make the adsorption tower is less than desorption regeneration's temperature, the low adsorption capacity that is favorable to increasing unit adsorbent of temperature during the absorption, the dynamic adsorption capacity that has increased the adsorbent that the temperature height when desorption regeneration was favorable to making the desorption of adsorbent more thoroughly. Meanwhile, because the gas is subjected to energy recovery through the expansion machine, the pressure boosting or reducing process of the adsorption tower tends to be slow, and compared with a pressure swing adsorption device without energy recovery, the impact load of the gas in the pressure equalizing process on the adsorption tower is reduced. The excessive and frequent impact load can lead the adsorbent to be easily pulverized, reduce the service life of the adsorbent and also have adverse effects on the safety and the fatigue service life of the adsorption tower. The use of an energy recovery device in the pressure swing adsorption unit can extend the life of the adsorbent and also contribute to the safety and fatigue life of the adsorption column.

And (4-5 min) reversely discharging the tower A, and pressurizing the tower B. The valve A4E13 is opened, and the high-pressure gas in the tower A is sent to other combustion devices after pressure energy and cold energy are recovered by the energy recovery system and then sent to other combustion devices through the reverse-bleeding buffer tank (7) and the reverse-bleeding compressor (8). Similar to the operation condition of the energy recovery system in the pressure equalizing process, the impact load formed at the moment of opening the valve is buffered by the regulating valve group E6E8E9, the buffer tanks (13) (15) (16), the flywheel and the capacitor group (10), and the impact load can be buffered to a certain extent by the connection of a large power grid and the regulation of the slide valve of the expansion machine. Similarly to the operation of the energy recovery system in the pressure equalizing process, along with the increase of the operation time, the pressure of the gas in the tower a is gradually reduced, the pressure difference of the gas between the inlet and the outlet of the expander is gradually reduced, and the flow is also gradually reduced, so that the shaft power output by the expander is gradually reduced, the shaft power output by the motor is gradually increased, and the current input by the power grid needs to be adjusted to be gradually increased through the control system to supplement the shaft power required by the compressed gas. The current required by the motor needs to be connected into the whole power grid, the control device is applied to complete the stable driving of the motor by utilizing the capacity of the large power grid for the current which changes periodically and rapidly, and the capacitor bank also contributes to the stable driving of the motor through the input and the output of the current. Meanwhile, the slide valve of the screw expander is adjusted through the adjusting control mechanism, so that the flow rate, the internal pressure ratio and the internal volume ratio of the expander can be suitable for the external pressure ratio and the flow rate of the inlet and the outlet of the expander after the valve is opened, and the expander can keep high efficiency. And the cold energy with certain temperature is output to the outside through the heat exchanger at the outlet of the expansion machine for other devices to use. The operation condition of the energy recovery system is similar to that of the energy recovery system in the pressure equalizing process, and the energy recovery system is added in the process of overlarge pressure change, so that the service life of the adsorbent is prolonged, and the safety and the fatigue service life of the adsorption tower are also facilitated. And opening a valve E1E2B3, and pressurizing the tower B after the pressure energy and the cold energy of the high-pressure gas in the product gas pressure stabilizing tank (19) are recovered by an energy recovery system, so that the pressure of the tower B is increased to be close to the pressure in the adsorption step. In the process, the energy recovery system is similar to the process of sequentially discharging the A tower, namely the coping mode of the impact load of the open valve, the stable driving of the change of the input current in the power grid, the external supply of cold energy through the heat exchanger, the adjustment of the flow rate, the internal pressure ratio and the internal volume ratio of the expansion machine by the slide valve and the process of sequentially discharging the A tower are similar. The temperature of the gas after certain cold energy is recovered through heat exchange is lower than that of the gas at the inlet end of the expansion machine, and the temperature of the tower B is reduced due to the entering of low-temperature gas.

And in the process of vacuumizing the tower B in the time period of (5-8 min), opening a valve A6 and vacuumizing the tower A by using a reciprocating pump (6). The tower B is in an adsorption state, and the feed gas enters the tower B to be adsorbed through a feed gas surge tank (18) and an adjusting valve E4; the gas which is not adsorbed at the tower top passes through a product gas pressure stabilizing tank (19) and a regulating valve E3 to be used as the product gas for other devices. The temperature of the gas which is received by the tower B after energy recovery is lower than that of the gas at the inlet end of the expander in the previous pressure equalizing and increasing processes. The adsorption temperature that can make the B tower can reduce, and in the step of B absorption, the adsorption temperature that can make the adsorption tower is less than the regenerated temperature of evacuation desorption, and the temperature during absorption is low to be favorable to increasing the adsorption capacity of unit adsorbent, and the temperature height during desorption regeneration is favorable to making the more thorough of desorption of adsorbent, has increased the dynamic adsorption capacity of adsorbent. During this time, no gas passes through the energy recovery device, and no recovered energy is supplied to the compressor (3) for gas compression.

And (3) carrying out the pressure equalizing process of the tower B and the tower A in a (8-9 min) time period, opening a valve B2A3, and boosting the pressure of the tower A by using high-pressure gas in the tower B. The process is similar to the pressure equalizing process of the (3-4 min) section, and the tower A and the tower B are matched with each other and alternately perform continuous operation in a circulating reciprocating manner.

And (4) performing a pressurizing process on the tower A and performing a reverse discharging process on the tower B in a (9-10 min) time period. And a valve E1E2B3 is arranged, and the high-pressure gas in the product gas pressure stabilizing tank (19) is pressurized to the tower A after pressure energy and cold energy are recovered by an energy recovery system, so that the pressure of the tower A is increased to be close to the pressure in the adsorption step. The valve B4E13 is opened, and the high-pressure gas in the tower A is sent to other combustion devices after pressure energy and cold energy are recovered by the energy recovery system and then sent to other combustion devices after passing through the reverse-bleeding buffer tank (7) and the reverse-bleeding compressor (8). The process is similar to the process of reversely discharging the tower A in the section (4-5 min), and the pressurizing process of the tower B is similar to the process of alternately and continuously operating the tower A and the tower B in a circulating reciprocating manner.

Thus, the adsorption tower completes a complete adsorption-regeneration cycle and is ready for the next cycle. The operation process of the tower B is the same as that of the tower A, each adsorption tower alternately performs the operation of each step, the single tower is circularly and continuously operated, and the towers are mutually matched and alternately circularly and continuously operated.

Pressure swing adsorption separation of H by pressure swing adsorption₂In the process of (1), the periodic rapid change of pressure energy is recovered and converted into conventionally available mechanical energy to supply the pair H₂The pressurizing process and the externally output cold energy save the pair H₂The electrical energy consumed by the pressurization. In contrast to pressure swing adsorption systems that do not incorporate an energy recovery device, it is possible to recover energy due to pressure differentials in conventional pressure swing adsorption systemsThe amount lost 46%.

TABLE 6 two-tower pressure swing adsorption purification of H₂Cycle operation step timing chart

Example 5 this example illustrates the energy recovery process in a three column pressure swing adsorption

Some tail gas also contains trace N₂、CO、CO₂、CH₄And Ar and other impurities, and a hydrogen separation unit is required to be arranged for separation and purification in order to meet the requirement of the product hydrogen. The pressure of the raw material gas entering the pressure swing adsorption separation device of H2 is higher due to the higher operation pressure of the upstream device, and the separated H needs to be completed₂Pressurization to 4.2MPa (G) is required.

The raw material gas condition is as follows:

component (Dry basis)

CO

H₂

CO₂

N₂

Ar

CH₄

H₂S+COS

Vol，％

11.179

68.28

10.004

10.227

0.003

0.308

0.1ppm

Flow rate: 2000Nm³H (dry basis)

Pressure: 2.2MPa (G)

Temperature: about 32 DEG C

Is filled with H₂The pressure swing adsorption purification device for separating the special adsorbent is used for separating and purifying, and the separation step comprises the following steps: adsorption, pressure equalizing and reducing, reverse pressure releasing, vacuumizing, pressure equalizing and increasing and finally pressure increasing. The method comprises the following steps of: energy is recovered by adopting an energy recovery and pressurization coupled device in voltage equalizing, reverse voltage releasing and final voltage boosting, and H is completed simultaneously₂The special separation and purification. The energy recovery and pressurization coupling device is a system consisting of a turboexpander, a compressor and an electric compressor, and a capacitor bank, an adjusting valve bank, a flywheel, a plurality of buffer tanks, a gearbox, a control system and other complex systems which have auxiliary functions. In the presence of pressurized H₂Buffer tanks of a certain volume are added before entering the compressor in the energy recovery device and after leaving the energy recovery device to stabilize the pressurized H₂To make it substantially stable.

As shown in fig. 9.

Similar processes are used for energy recovery in the various steps of the pressure swing adsorption and energy recovery and pressurization coupled apparatus. The pressure in the pipeline at the moment of opening the valve in the operation step conversion process and the pressure difference change at the inlet and outlet ends of the adjusting expansion machine are large in the operation process, so that larger impact load can be caused, and the stable and safe operation of equipment and the service life of the equipment can be influenced by the overlarge impact load. Therefore, the pressure difference and the flow of the inlet and the outlet of the expansion machine are adjusted by the adjusting valve E2E5, the opening degree of the adjusting valve E2E5 is reduced at the moment of opening the valve, and the corresponding adsorption tower is subjected to pressure building, so that the influence of impact load on the expansion machine is reduced. And the buffer tanks (13), (14), (15) and (16) are connected with the inlet and outlet pipelines of the expander for buffering, when the pressure in the pipeline connected with the buffer tanks is higher than the pressure set by the valve E6E7E8E9, the valve E6E7E8E9 is opened, the buffer tanks are communicated with the pipelines, so that the gas is shunted to enter the buffer tanks, the amount of the gas entering the expander is reduced, the influence of impact load is reduced, the required time is strived for the action of an adjusting mechanism of the expander, the adjusting and controlling mechanism is enabled to operate the deflection angle of an inlet guide vane of the turboexpander or the opening degree of an adjustable nozzle, and the flow passing through the expander and the pressure difference can be suitable for the pressure difference and the flow at the inlet and the outlet of the expander after the valve is. Meanwhile, the pressure energy acting on the expansion machine drives the shaft to rotate and is converted into mechanical energy of the shaft, the impact load formed when the valve is opened is easy to drive the rotating speed of the shaft to accelerate, the change of the rotating speed of the shaft is not beneficial to forming resultant force with the motor to jointly drive the compressor to complete the compression process of another gas, and the flywheel with certain size and certain mass distribution is added on the rotating shaft to increase the rotational inertia of the shaft, so that the acceleration obtained by the rotating shaft is reduced under the same torque. The current required by the motor needs to be connected into the whole power grid, and the stable driving of the motor is completed by using the capacity of the large power grid for the current which changes periodically and rapidly and applying a control device. Under the action of impact load, the flow of current input by the motor by the power grid can be rapidly reduced, even the transmission direction of the current is changed, so that the rapid change of the flow of the current caused under the action of the impact load is stabilized by connecting the motor and the capacitor bank, the response capability of a motor system to the rotation energy required by the rapidly-changing rotating shaft can be enhanced, and the impact on the power grid is reduced. Along with the increase of the operation time, the gas in the high-pressure tower gradually flows to the low-pressure tower or the pressure stabilizing tank, the pressure of the high-pressure tower is gradually reduced, the pressure of the low-pressure tower is gradually increased, the pressure difference between the two towers is gradually reduced, the pressure difference of the gas between the inlet and the outlet of the expansion machine is gradually reduced, the flow rate is also gradually reduced, and the process is gradually changed. The opening degree of the regulating valve E2E5 is adjusted larger, reducing the resistance loss at the valve. When the pressure in the pipeline at the inlet and the outlet of the expander is gradually changed, the gas is gradually changed from the inflow buffer tank to the outflow buffer tank, and when the pressure in the pipeline connected with the buffer tank is lower than the pressure set by the valve E6E7E8E9, the valve E6E7E8E9 is closed, and the buffer tank is not communicated with the pipeline. The compressed gas needs basically stable pressure and flow, which means that the shaft power needed by the compressed gas needs to be basically stable, so that the compressed gas is connected to the buffer tank at the inlet and the outlet of the compressor to cope with possible pressure and flow fluctuation, the pressure difference of the gas between the inlet and the outlet of the expander is gradually reduced along with the change of time, the flow is also gradually reduced, the shaft power output by the expander is also gradually reduced, the shaft power output by the motor needs to be gradually increased, and the current input by a power grid needs to be adjusted to be gradually increased through the control system to supplement the shaft power needed by the compressed gas. The current required by the motor needs to be connected into the whole power grid, and the stable driving of the motor is completed by using the capacity of the large power grid for the current which changes periodically and rapidly and applying a control device. Meanwhile, the deflection angle of an inlet guide vane of the turbo expander or the opening degree of an adjustable nozzle is adjusted through an adjusting control mechanism, and the flow and the pressure difference of the expander are adjusted to keep the efficiency of the expander higher. Because the energy recovery process is an expansion process of reducing the pressure and outputting work to the outside, the temperature of the gas at the outlet of the expansion machine is reduced, the temperature reduction amplitude is determined by the pressure difference at the inlet and the outlet of the expansion machine, and the gas at the outlet of the expansion machine outputs cold energy with certain temperature to the outside through the heat exchanger for other devices to use. The gas at the outlet of the expansion machine enters the low-pressure tower, the pressure of the low-pressure tower is increased, the temperature of the gas after certain cold energy is recovered through heat exchange is lower than that of the gas at the inlet end of the expansion machine, and the temperature of the low-pressure tower is reduced through the low-temperature gas. To the low pressure column, the process that the entering that the similar low temperature gas had also existed in the pressure boost process in next step makes the temperature reduction of low pressure column, can make the low pressure column carry out the step of adsorbing after stepping up, the adsorption temperature of low pressure column can reduce, the adsorption temperature that can make the adsorption tower is less than desorption regeneration's temperature, the temperature during absorption is low is favorable to increasing the adsorption capacity of unit adsorbent, the temperature height during desorption regeneration is favorable to making the more thorough dynamic adsorption capacity that has increased the adsorbent of desorption of adsorbent. Meanwhile, because the gas is subjected to energy recovery through the expansion machine, the pressure boosting or reducing process of the adsorption tower tends to be slow, and compared with a pressure swing adsorption device without energy recovery, the impact load of the gas in the pressure equalizing process on the adsorption tower is reduced. The excessive and frequent impact load can lead the adsorbent to be easily pulverized, reduce the service life of the adsorbent and also have adverse effects on the safety and the fatigue service life of the adsorption tower. The use of an energy recovery device in the pressure swing adsorption unit can extend the life of the adsorbent and also contribute to the safety and fatigue life of the adsorption column.

Briefly, a buffer tank with a certain volume and a regulating valve group are added in a pressure swing adsorption and energy recovery and pressurization coupled device to stabilize the fluctuation of pressure or flow of gas in a pipeline, and a turbo expander recovers the energy of the pressure swing adsorption medium gas and converts the energy into mechanical energy of a shaft. A flywheel with a certain size and certain mass distribution is added into the energy recovery device to increase the rotational inertia of the shaft, so that the rotational energy of the rotating shaft which is periodically and rapidly changed is stabilized. Then the control system determines the output required by the electric compressor according to the total energy required by the system, controls the output of the motor, and supplies energy by the electric compressor or the electric pump to supplement the required residual energy pair H₂The pressurization process is completed. The motor is connected with the capacitor bank, when the current fluctuation is large, the battery bank can quickly stabilize the current rapid change, and the response of the motor system to the rotation energy required by the rapidly-changed rotating shaft can be enhanced. The current required by the motor needs to be connected into the whole power grid, and the stable driving of the motor is completed by using the capacity of the large power grid for the current which changes periodically and rapidly and applying a control device. Thereby separating H from the pressure swing adsorption₂In the process of (1), the periodic rapid change of pressure energy is recovered and converted into conventionally available mechanical energy to supply the pair H₂The pressurizing process saves the H₂The electrical energy consumed by the pressurization. In contrast to a pressure swing adsorption system without an added energy recovery device, it can recover 46% of the energy loss due to pressure differential in a conventional pressure swing adsorption system. In the pressure swing adsorption process, according to a three-tower pressure swing adsorption purification H2 cyclic operation step timing chart (table 7), each adsorption tower alternately performs the operation of the above steps, performs cyclic reciprocating continuous operation on a single tower, and performs cyclic reciprocating continuous operation alternately by matching the towers.

The reverse air release and the air pumping are used as waste gas to be led to a waste gas flare pipe network of a plant area and pass through H₂The purity of H2 with the purity of more than or equal to 99.9 percent obtained by the adsorption separation device is 1300Nm³H, the balance of CO is about 0.03%, CO₂About 0.03%, N₂About 0.03%, Ar + CH₄About 0.01%; reverse air bleed and evacuation of 700Nm³A/h, wherein the CO is about 31.94%, CO₂About 28.59%, N₂About 29.22%, H₂About 9.37%, CH₄About 0.88%.

Pressure swing adsorption separation of H₂The pressure swing adsorption process is illustrated by taking tower A as an example:

(a) Adsorption (0-2 min): under the pressure of 2.2MPa, a valve A4 opens the raw material gas to enter a fixed bed layer for adsorption, the adsorption is stopped before the adsorption front reaches one end of the bed layer outlet, a section of fresh bed layer is reserved between the adsorption front and the bed layer outlet, and H obtained at the top of the tower₂And discharged as product gas through an open valve a1 at the top of the column. The adsorption pressure is close to the pressure of the raw material gas incoming material.

(b) Adsorption (2-3 min): while the tower A is adsorbing, the outlet of the tower A is connected with the tower B after being uniformly lifted, and part of H obtained from the tower top is used₂And (3) carrying out a pressurizing step on the tower B, wherein energy is recovered through an energy recovery and pressurizing coupling device, a valve A1A4 is opened, a valve A2 at the top of the tower A, a valve B3 at the bottom of the tower B and a valve E3E6E7 are opened, E6 is closed when the pressure of gas in a tank connected with E6 is lower than 1.9MPa, and E7 is closed when the pressure of gas in a tank connected with E7 is lower than 1.4 MPa. The regulating valve groups E2, E5 are used for regulating the pressure and air in the pipelinesThe volume flow is gradually increased or decreased, and the fluctuation of the operation of the turboexpander (2) can be reduced. The buffer tank connected with the valve of the E6E7 and the regulating valve groups E2 and E5 can buffer the flow and the pressure difference of gas passing through the turboexpander at the moment when the valve is just opened, and can reduce the instantaneous output of the turboexpander.

(c) Uniformly reducing (3-4 min): connecting the tower A with the tower C in a vacuum state to carry out a pressure equalizing step, wherein energy is recovered through an energy recovery and pressurization coupling device, a valve A2 at the top of the tower A, a valve C3 at the bottom of the tower C and a valve E3E6E9 at the bottom of the tower C are opened, E6 is closed when the pressure of gas in a tank connected with E6 is lower than 1.9MPa, and E7 is closed when the pressure of gas in a tank connected with E9 is lower than 0.4 MPa. The regulating valve groups E2, E5 are intended to regulate the pressure and gas flow in the lines to be progressively higher or lower, so as to reduce the fluctuations that cause the turboexpander to operate. The buffer tank connected with the valve of the E6E9 and the regulating valve groups E2 and E5 can buffer the flow and the pressure difference of gas passing through the turboexpander at the moment when the valve is just opened, and can reduce the instantaneous output of the turboexpander. For column a, a first depressurization step, and for column C, a first pressure increase step. The pressure of the tower A after pressure equalization is slightly higher than half of the original pressure (1.1MPa), and the purity of the pressure equalization gas is basically the same as that of the product gas flowing out of the tower top.

(d) Reverse amplification (4-5 min): the tower A is connected with a reverse-discharging buffer tank in a near-atmospheric state to carry out a reverse-discharging step, a reverse-discharging loop needs to recover energy through an energy recovery and pressurization coupling device at the same time, a valve A3 at the bottom of the tower A and a valve E1E4E8E9 are opened, E8 is closed when the pressure of gas in a tank connected with E8 is lower than 0.9MPa, and E9 is closed when the pressure of gas in a tank connected with E9 is lower than 0.4 MPa. The regulating valve groups E2, E5 are intended to regulate the pressure and gas flow in the lines to be progressively higher or lower, so as to reduce the fluctuations that cause the turboexpander to operate. The buffer tank connected with the valve of the E8E9 and the regulating valve groups E2 and E5 can buffer the flow and the pressure difference of gas passing through the turboexpander at the moment when the valve is just opened, and can reduce the instantaneous output of the turboexpander. After the pressure equalizing and reducing process is finished, the front edge of impurities in the adsorption bed reaches the outlet position of the adsorption tower. At this time, the pressure in the adsorption column was reduced to near atmospheric pressure (0.11MPa) against the adsorption direction. In this process, the adsorbed impurities in the adsorption tower begin to be desorbed from the adsorbent in large quantities. The reverse discharge gas goes to other combustion devices after passing through a reverse discharge buffer tank (7) and a reverse discharge gas compressor (8).

(e) Vacuumizing (5-6 min): after the reverse discharging step is finished, in order to ensure that the adsorbent is regenerated more thoroughly, the adsorption tower is pumped out, so that the adsorbent is desorbed thoroughly. The valve A5 at the bottom of the tower A is opened, the bed layer is reversely vacuumized by a vacuum pump (6), and the pressure in the tower is reduced to-0.09 MPa.

(f) Uniformly rising (6-7 min): connecting the tower A in a vacuum state with the tower B in an adsorption state to carry out a pressure equalizing step. The first stage of the pressure charging process is for column A and the first stage of the pressure reducing process is for column B. And (c) opening valves of a tower bottom valve A3, a tower top valve B2 and an E3E6E9 of the tower A, recovering energy through an energy recovery and pressurization coupling device, wherein the process is similar to the process of (c) reducing, and only the tower A becomes a pressure equalizing and boosting low-pressure tower for receiving gas. The pressure of the tower A after pressure equalization is slightly lower than half (0.9MPa) of the pressure of the adsorption step, and the purity of the pressure equalization gas is basically the same as that of the product gas flowing out of the tower top of the tower B.

(g) Vacant (7-8 min): and valves at the top and the bottom of the tower A are closed, no gas enters or exits the tower A, and the tower A is in a waiting state.

(h) Pressurizing (8-9 min): the column A was pressurized with a portion H2 for connecting the column A and the column C after the pressure equalization to raise the internal pressure of the column A to a pressure close to the adsorption pressure (2.1 MPa). The process of recovering energy through the energy recovery and pressurization coupled device is similar to the process of (b) adsorption, but the tower A is changed into a pressurized low-pressure tower for receiving gas.

Thus, the adsorption tower completes a complete adsorption-regeneration cycle and is ready for the next cycle. The operation process of other three towers is the same as that of the tower A, each adsorption tower alternately carries out the operation of the steps, single tower is circularly and continuously operated, and towers are mutually matched and alternately circularly and continuously operated.

The specific operation steps, operation time and sequence are shown in table 1, and the control and operation of the open state of each valve of each tower are shown in table 7. According to the time sequence table (table 7) and the valve opening control table (table 8), the energy recovery system can be known to be in a continuous working state, the pressure equalizing, reverse releasing and pressurizing processes alternately occur, the energy recovery system alternately carries out continuous operation in a circulating reciprocating mode, the energy recovery system continuously operates, and energy in the 3 operation steps is recovered, so that the energy recovery system is prevented from being unloaded, the safe and stable operation of a machine is facilitated, and the adverse effect on the machine and the loss of energy are avoided.

TABLE 7 three-tower pressure swing adsorption purification of H₂cycle operation step timing chart

TABLE 8 control table for opening of valve of each tower

。

Claims

1. Coal gas production H₂a plant for a/CO feed gas, comprising:

The first pretreatment device is used for pretreating the gas feed gas;

2. Gas production H according to claim 1₂The device for producing the alcohol is characterized by also comprising a device for producing the alcohol, a CO outlet connected with the pressure swing adsorption device and H₂H of the separation apparatus₂And the outlet is used for reacting and synthesizing alcohol with the carbon atom number more than or equal to 2.

3. Gas production H according to claim 1₂The device for the/CO raw material gas is characterized in that the first pretreatment device is connected to a raw material gas output port mainly containing blast furnace gas or converter gas.

4. Coal gas production H according to claim 3₂the device for the/CO raw material gas is characterized in that a raw material gas output port mainly containing blast furnace gas or converter gas is also connected with an inlet for tail gas or purge gas.

5. Gas production H according to claim 1₂The device for the/CO raw material gas is characterized in that the pressure swing adsorption device is connected with the shift reactor through a pipeline and is used for separating CO and N from the first part of gas by the pressure swing adsorption method₂And (3) mixing the replacement gas or/and the cis-bleed gas generated in the CO obtaining process with the second part of gas, and then carrying out a shift reaction.

6. Gas production H according to claim 1₂The device for the/CO raw material gas is characterized in that the first pretreatment device comprises a dust removal device, a phosphorus removal device, an arsenic removal device, a dehydration device, a dehydrogenation and deoxidation device, a desulfurization device and a CO removal device₂Plant, CO removal plant or CH removal₄One or a combination of several of the devices.

7. Coal gas production H according to claim 6₂The device for preparing the/CO raw material gas is characterized in that the first pretreatment device comprises a desulfurization device and a CO removal device₂Apparatus, CO removal₂integration of the plant with a desulfurization plant or CO removal₂The unit is located downstream of the desulfurization unit.

8. Coal gas production H according to claim 7₂The device for preparing the/CO raw material gas is characterized in that the first pretreatment device also comprises CH removing device₄A device or/and a dehydrogenation deoxidation device; except CH₄The device is arranged at the downstream side of the desulfurization device; the dehydrogenation and deoxidation device is in CH removal state₄The downstream side of the apparatus; shunting device and CH removing device₄The gas outlet of the device, the gas outlet of the desulphurization device or the gas outlet of the dehydrogenation and deoxidation device are connected.

9. Gas production H according to claim 1₂The device for the/CO raw material gas is characterized in that a gas inlet of a shift reactor is connected with a second pretreatment device, the second pretreatment device comprises a first pretreatment device and an independent pretreatment device, the first pretreatment device passes through when two parts of gas are in a mixed state, the independent pretreatment device is connected with the second pretreatment device through a flow dividing device, and the second pretreatment device comprises a dust removal device, a phosphorus removal device, an arsenic removal device, a dehydration device, a dehydrogenation and deoxidation device, a desulfurization device and a CO removal device₂Device, remove CH₄One or more of the devices and recombination removal devices.

10. Gas production H according to claim 1₂A plant for producing a/CO feed gas, characterized in that H₂The separation device is a second pressure swing adsorption device, or H₂The separation device adopts a series absorption method to remove CO₂The device and a third pressure swing adsorption device.

11. Coal gas production H according to claim 10₂The device for the/CO raw material gas is characterized in that CO is removed in the first pretreatment device₂The device is a pressure swing adsorption method for removing CO₂CO removal by means of apparatus or absorption₂Apparatus for CO removal by absorption₂In the device, the absorption method in the first pretreatment device removes CO₂The absorption liquid outlet of the device is connected with the H₂Absorption CO removal in a separation plant₂Provided is a device.