CN111013536A

CN111013536A - Preparation of medium-temperature renewable hydrogen sulfide adsorbent and circulating desulfurization method thereof

Info

Publication number: CN111013536A
Application number: CN201911374144.2A
Authority: CN
Inventors: 史翊翔; 李爽; 蔡宁生; 郝培璇
Original assignee: Tsinghua University; Shanxi Research Institute for Clean Energy of Tsinghua University
Current assignee: Tsinghua University; Shanxi Research Institute for Clean Energy of Tsinghua University
Priority date: 2019-12-26
Filing date: 2019-12-26
Publication date: 2020-04-17

Abstract

The invention discloses a preparation method of a medium-temperature renewable hydrogen sulfide adsorbent and a circulating desulfurization method thereof. Weighing a proper amount of activated carbon from coal or biomass and the like, putting the activated carbon into a reactor (such as a high-pressure reaction kettle), heating the reactor to 50-200 ℃, and vacuumizing the reactor for more than 10 min. Introducing the mixed gas of nitrogen and fluorine into a reactor, and fluorinating the activated carbon at 40-120 ℃ for more than 5min to obtain the fluorinated activated carbon. Adding dimethyl silicone oil and ethyl orthosilicate serving as mixed liquid into a solution box, putting the solution box into a reactor, and heating at a constant temperature of 150-500 ℃ to enable fluorinated activated carbon and mixed liquid steam to continuously react for more than 20min, so as to obtain the medium-temperature renewable hydrogen sulfide adsorbent. And (3) filling the prepared adsorbent into a desulfurizing tower, and performing medium-temperature vacuum pressure swing adsorption type desulfurization enrichment. The adsorbent of the present invention has the advantages of adsorption-desorption regeneration function, high hydrogen sulfide recovery rate, etc.

Description

Preparation of medium-temperature renewable hydrogen sulfide adsorbent and circulating desulfurization method thereof

Technical Field

The invention relates to a preparation method of a medium-temperature renewable hydrogen sulfide adsorbent and a circulating desulfurization method thereof, belonging to the technical field of gas purification.

Background

The synthesis gas/coke oven gas produced by using coal, natural gas, naphtha, heavy oil and the like as raw materials and performing gasification, coking and other processes, and the like, wherein the main component is H₂、CO、CO₂、N₂、CH₄Steam, etc., which is converted or hydrolyzed for desulfurization convenience, and the sulfur content of the coal is generally present in a state of hydrogen sulfide of not more than 2000 ppm. No matter the subsequent purification link is utilized or the environmental protection is considered, H needs to be purified by a purification working section₂S is removed to obtain ideal product gas. The purification method is generally a wet method and a dry method, wherein the wet method is represented by low-temperature methanol washing, an active alcamines solution, a tannin extract method, an NHD method and the like, the operation temperature is generally lower than 100 ℃, and the dry method is typically represented by pressure swing adsorption decarburization, but dehydration and desulfurization are required in advance. The existing mature processes are generally divided into two types, one type is that the sulfur and carbon components are removed to be within 10ppm by the wet process, and then liquid nitrogen is used for washing and fine removal to ensure the purification precision; or after wet desulfurization and decarburization, gas-solid catalytic absorption methods such as Fe-based and Zn-based solid desulfurizing agents are connected to ensure desulfurization precision. But the wet method has the defects of high operation cost, large power consumption, more complex process flow, leakage and secondary pollution and the like; while dry desulfurization has high precision, the desulfurizing agent is a waste type, and a new adsorbent is in a new state after adsorption/reaction saturation, so that solid waste pollution is aggravated. How to combine the conditions of high sulfur content and high carbon content of the inlet of wet purification treatment and reversible operation, and the dry method has low energy consumption andthe simple operation process is a difficult problem of industrial desulfurization, decarburization and purification process. Patent document CN201110199645.9 discloses a method for CO₂、H₂S and H₂The medium temperature pressure swing adsorption method for separating mixed gas provides an original modification mode at the medium temperature on the basis of the patent, improves the selective adsorption of the low-temperature adsorbent active carbon to hydrogen sulfide and the tolerance to water vapor at the medium temperature (110-250 ℃) to ensure that the low-temperature adsorbent active carbon has the reversible H removal performance which is not provided under the normal temperature or low temperature operation condition₂The ability of S. On the basis, a matched circulating desulfurization process is provided, so that the sulfur component can be reversibly desorbed under the operating conditions of constant temperature and variable partial pressure, and hydrogen sulfide is desorbed and enriched in the form of hydrogen sulfide, thereby achieving the operation purpose of circulating purification.

Disclosure of Invention

The invention aims to provide a preparation method of a medium-temperature renewable hydrogen sulfide adsorbent and a cyclic desulfurization method thereof, which can realize cyclic desulfurization and recover hydrogen sulfide.

The invention is realized by the following technical scheme:

a preparation method of a medium-temperature regenerable hydrogen sulfide adsorbent comprises the following steps:

weighing a proper amount of activated carbon, putting the activated carbon into a reactor, heating the reactor to 50-200 ℃, and vacuumizing the reactor;

introducing a mixed gas of nitrogen and fluorine gas into the reactor according to the volume ratio of the nitrogen to the fluorine gas of 20: 1-7: 3, and fluorinating the activated carbon at 40-120 ℃ for more than 5min to obtain fluorinated activated carbon;

mixing dimethyl silicone oil and ethyl orthosilicate according to a volume ratio of 50: 1-8: 1 to obtain a mixed solution, adding the mixed solution and the fluorinated activated carbon into a solution box according to a ratio of 0.05-1 mL/g, placing the solution box into the reactor, and heating at a constant temperature of 150-500 ℃ to enable the fluorinated activated carbon and the mixed solution steam to continuously react for more than 20min, so as to obtain the medium-temperature renewable hydrogen sulfide adsorbent.

In the technical scheme, the reactor is a high-pressure reaction kettle.

In the technical scheme, the vacuumizing treatment lasts for more than 10 min.

A medium-temperature circulating desulfurization method uses a purification system comprising a desulfurization tower and a vacuum pump, wherein one end of the desulfurization tower is provided with an air inlet, a reverse release port and a vacuumizing port, and the other end of the desulfurization tower is provided with an air outlet and a purge gas port; the method comprises the following steps;

placing the prepared medium-temperature regenerable hydrogen sulfide adsorbent into the desulfurizing tower;

introducing a purging gas into the desulfurizing tower through a purging gas port to purge the desulfurizing tower, so that the pressure in the desulfurizing tower is the same as the pressure of the feed gas, and completing a purging and pressurizing stage;

closing the purge gas port, opening the gas inlet and the gas outlet, and allowing the gas to contain H₂Introducing the raw material gas of the S into a desulfurizing tower through a gas inlet; h in the feed gas₂S is adsorbed by the medium-temperature regenerable hydrogen sulfide adsorbent, and H is removed₂The treated gas of S flows out from the gas outlet until the medium-temperature regenerable hydrogen sulfide adsorbent is saturated, and the desulfurization stage is completed;

then closing the air inlet and the air outlet, and opening the reverse release port to reversely reduce the pressure in the desulfurizing tower to be below 0.5MPa, thereby completing the reverse release stage;

closing the reverse release port, opening the vacuum-pumping port to communicate with the vacuum pump inlet, further reversely reducing the pressure in the desulfurizing tower, and collecting the desorption gas from the vacuum pump outlet to obtain H₂S enriched sulfur-containing gas;

and closing the vacuumizing port, and opening the blowing gas port and the reverse releasing port to reversely introduce blowing gas into the desulfurizing tower.

In the technical scheme, the working temperature of the desulfurizing tower is 110-250 ℃.

In the technical scheme, the pressure of the raw material gas is 0.05-20 MPa.

In the above technical solution, the purge gas includes any one or a mixture of a plurality of nitrogen, carbon dioxide, methane, and water vapor.

The invention has the following advantages and beneficial effects: through the surface treatment of the activated carbon, the proportion of oxygen-containing functional groups on the surface of the activated carbon is reduced, and the ratio of the activated carbon to H is weakened₂The binding force of S is favorable for H₂Smoothly desorbing the S; the surface treatment of oily substances enhances the hydrophobicity of the activated carbon and weakens the influence of steam purging on the performance of the adsorbent; the corresponding medium-temperature circulating desulfurization method is designed, sulfur-containing components in the raw material gas are removed, and the sulfur-containing components are recovered in a hydrogen sulfide form, so that the enrichment rate is high, and the process is simple.

Drawings

FIG. 1 is a schematic diagram of the operation of the medium-temperature cyclic desulfurization method according to the present invention.

Detailed Description

The following will further describe the specific implementation and operation of the present invention with reference to the drawings and examples.

Weighing a proper amount of activated carbon from coal or biomass and the like, putting the activated carbon into a reactor (such as a high-pressure reaction kettle), heating the reactor to 50-200 ℃, and vacuumizing the reactor for more than 10 min. And introducing the mixed gas of the nitrogen and the fluorine into a reactor according to the volume ratio of the nitrogen to the fluorine being 20: 1-7: 3, and fluorinating the activated carbon at 40-120 ℃ for more than 5min to obtain the fluorinated activated carbon.

Mixing dimethyl silicone oil and ethyl orthosilicate according to a volume ratio of 50: 1-8: 1 to obtain a mixed solution, adding the mixed solution and fluorinated activated carbon into a solution box according to a ratio of 0.05-1 mL/g, putting the solution box into a reactor, and heating at a constant temperature of 150-500 ℃ to enable the fluorinated activated carbon and the mixed solution steam to continuously react for more than 20min, thereby obtaining the medium-temperature renewable hydrogen sulfide adsorbent.

The prepared medium-temperature regenerable hydrogen sulfide adsorbent is filled into a desulfurizing tower shown in figure 1 to sequentially carry out adsorption and regeneration circulation processes.

And introducing a purging gas into the desulfurizing tower through a purging gas port to purge the desulfurizing tower, so that the pressure in the desulfurizing tower is the same as the pressure of the feed gas, and completing a purging and pressurizing stage. The purge gas comprises any one or more of nitrogen, carbon dioxide, methane, water vapor. The pressure of the raw material gas is 0.05-20 MPa.

Closing the purge gas port, opening the gas inlet and the gas outlet, and allowing the gas to contain H₂Introducing the raw material gas of the S into a desulfurizing tower through a gas inlet; h in the feed gas₂S is adsorbed by the medium-temperature reproducible hydrogen sulfide adsorbent, and H is removed₂And (4) allowing the treated gas of the S to flow out from the gas outlet until the medium-temperature regenerable hydrogen sulfide adsorbent is saturated, and completing the desulfurization stage. The working temperature of the desulfurizing tower is 110-250 ℃.

and closing the vacuumizing port, opening the blowing gas port and the reverse releasing port, reversely introducing blowing gas into the desulfurizing tower to blow the desulfurizing tower, and circularly repeating the process.

The medium-temperature cyclic desulfurization process is essentially a medium-temperature vacuum pressure swing adsorption process, and a reaction system of the medium-temperature cyclic desulfurization process is also called a medium-temperature vacuum pressure swing adsorption system.

Example 1: preparation of coal-based reversible desulfurization activated carbon

The preparation method of the reversible desulfurization activated carbon taking the anthracite and the lignite as raw materials comprises the following specific steps:

putting a proper amount of coal-based activated carbon into a high-pressure reactor, putting the reactor into a nickel protective device, and vacuumizing for 2 hours at 100 ℃; heating to 120 ℃, mixing high-purity nitrogen and fluorine gas according to a fixed ratio of 7:3, introducing into a reaction, and fluorinating for 10 min. Adding a beaker filled with mixed liquid of dimethyl silicone oil and ethyl orthosilicate into the reactor, wherein the volume ratio of the dimethyl silicone oil to the ethyl orthosilicate is 10:1, and separating the beaker from the activated carbon. The ratio of the liquid to the active carbon is 0.5 ml/g. And (3) closing a gas inlet and a gas outlet of the reactor, controlling the temperature of the reactor to be 200 ℃ under a closed condition, and carrying out constant-temperature heating treatment for 60min to obtain the coal-based reversible desulfurization activated carbon.

Example 2: preparation of coconut shell reversible desulfurization activated carbon

Placing the finished coconut shell activated carbon in a high-pressure reactor, placing the reactor in a nickel protective device, and vacuumizing for 2 hours at 50 ℃; heating to 100 ℃, mixing high-purity nitrogen and fluorine gas in a fixed ratio of 5:1, introducing into a reaction, and fluorinating for 10 min. Adding a beaker filled with mixed liquid of the dimethyl silicone oil and the tetraethoxysilane into the reactor, wherein the volume ratio of the dimethyl silicone oil to the tetraethoxysilane is 20:1, and separating the beaker from the activated carbon. The ratio of the liquid to the active carbon is 0.1 ml/g. And (3) closing a gas inlet and a gas outlet of the reactor, controlling the temperature of the reactor to be 200 ℃ under a closed condition, and carrying out constant-temperature heating treatment for 60min to obtain the coconut shell reversible desulfurization activated carbon.

Example 3: reversible desulfurization of dry coal-based conversion gas

The vacuum pressure swing adsorption system for purifying the dry-based coal-made conversion gas comprises 2 desulfurizing towers A, B, wherein coal reversible desulfurization activated carbon is filled in the desulfurizing towers, the temperature of the desulfurizing towers is kept at 160 ℃, and the adsorption pressure is 3.4 MPa; using N₂And CO₂(volume ratio 1:1) purging the mixed gas, wherein the purging pressure is normal pressure. The filling amount of the activated carbon is configured according to the flow rate of the raw material gas.

After the shift gas enters the A desulfurizing tower, H in the gas₂，CO₂，CO，N₂，CH₄Flowing out of the outlet of the desulfurization tower H₂S is adsorbed by the adsorbent. After about 1h, the adsorbent in A is saturated, B is replaced for adsorption, after the gas in A is reversely released to the normal pressure, the purge gas is reversely introduced for purging for 15min, the vacuum is pumped for desorption for 15min, and finally the purge gas is introduced for pressurizing to 3.4 MPaG; the gas discharged by the obtained reverse air release and vacuum pumping is uniformly introduced into a buffer tank for cooling. Finally, enriched H can be obtained in a buffer tank₂And (4) S gas.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. a preparation method of medium temperature regenerable hydrogen sulfide adsorbent, is characterized in that, described preparation method comprises:

Weigh an appropriate amount of activated carbon into the reactor, heat the reactor to 50-200°C, and vacuum the reactor;

According to the nitrogen to fluorine gas volume ratio of 20:1 to 7:3, the mixed gas of nitrogen and fluorine gas is introduced into the reactor, and the activated carbon is fluorinated at 40 to 120 ° C for more than 5 minutes to obtain fluorinated activated carbon;

Dimethicone and ethyl orthosilicate are mixed according to the volume ratio of 50:1 to 8:1 as a mixed solution, and added to the solution box according to the ratio of the mixed solution to the fluorinated activated carbon of 0.05 to 1 mL/g, and the described The solution box is put into the reactor, heated at a constant temperature of 150-500°C, and the fluorinated activated carbon is continuously reacted with the mixed liquid vapor for more than 20 minutes to obtain the medium-temperature regenerable hydrogen sulfide adsorbent.

2 . The method for preparing a medium-temperature regenerable hydrogen sulfide adsorbent according to claim 1 , wherein the vacuum treatment lasts for more than 10 min. 3 .

3. A medium-temperature cycle desulfurization method, characterized in that, the desulfurization method uses a purification system comprising a desulfurization tower and a vacuum pump, and one end of the desulfurization tower is provided with an air inlet, a reverse discharge port, and a vacuum outlet, and the other end is provided with a purifying system. an air outlet and a purge air port; the method includes;

Putting the mid-temperature regenerable hydrogen sulfide adsorbent as prepared in claim 1 into the desulfurization tower;

The purging gas is reversely fed into the desulfurization tower through the purging gas port, and the desulfurization tower is pressurized, so that the pressure in the desulfurization tower is the same as the pressure of the raw material gas, and the purging and pressurization stage is completed;

Close the purge air port, open the air inlet and air outlet, and pass the raw material gas containing H ₂ S into the desulfurization tower through the air inlet _; The process gas except H ₂ S flows out from the gas outlet until the medium-temperature regenerable hydrogen sulfide adsorbent is saturated, and the desulfurization stage is completed;

Then close the air inlet and outlet, and open the reverse discharge port to reverse the pressure in the desulfurization tower to below 0.5MPa, and complete the reverse discharge stage;

Close the reverse discharge port, open the vacuum pumping port, make it communicate with the inlet of the vacuum pump, further reverse the pressure in the desulfurization tower, collect the desorbed gas from the outlet of the vacuum pump, and obtain the sulfur-containing gas enriched with H ₂ S;

Close the vacuum port, open the purge gas port and the reverse discharge port, so that the purge gas flows into the desulfurization tower in the reverse direction.

4 . The medium-temperature cyclic desulfurization method according to claim 4 , wherein the working temperature of the desulfurization tower is 110-250° C. 5 .

5 . The medium-temperature cyclic desulfurization method according to claim 4 , wherein the pressure of the raw material gas is 0.05-20 MPa. 6 .

6 . A medium-temperature cyclic desulfurization method according to claim 4 , wherein the purge gas comprises any one or more mixtures of nitrogen, carbon dioxide, methane, and water vapor. 7 .