JP2010235915A - Gas refining facilities and power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide gas refining facilities capable of removing an impurity from gas produced from various fuels to refine into a hot gas and a highly efficient power generation system having the gas refining facilities. <P>SOLUTION: The gas refining facilities include: a scrubber 10 for washing gas containing a combustible component with a wet method; and desulfurization equipment 20 for removing a sulfur compound contained in the washed gas washed by the scrubber 10 with a dry method. In the gas refining facilities, the temperature of the washed gas introduced from the scrubber 10 to the desulfurization equipment 20 is retained at temperature at which a water vapor is not condensed. Thus, a refined gas suppressed with a decrease in temperature is obtained. Further, since the water vapor contained in the washed gas is not condensed, energy emitted with cooling of gas by washing with the scrubber 10 is not discharged from the gas refining facilities. Furthermore, since the progress of a chemical reaction which generates carbon from carbon monoxide in gas is suppressed by the water vapor in the washed gas, it can be avoided that solid carbon is deposited in a pipe, a heat exchanger, a reactor, an impurity removing agent and a power generator. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a high-performance and high-efficiency gas purification facility and a power generation system.

  From the viewpoint of the effective use of energy resources, for example, coal, heavy oil, biomass, or waste is gasified to produce gasified gas containing combustible components, and power generation is performed using the gasified gas as fuel. Power generation systems are being considered. Since gasified gas contains impurities that affect power generation facilities and the environment, technology for removing impurities from the gasified gas and refining it to high-quality fuel gas is indispensable. It has been proposed (see, for example, Patent Document 1).

  For example, Patent Document 1 proposes a gas purification method and a gas purification apparatus that remove impurities in the gasification gas by wet gas purification in which the gasification gas is washed with an absorbing solution or the like.

  In the power generation system using the fuel gas purified by the wet gas purification apparatus, there is a problem that the power generation efficiency is reduced due to the gas purification. In the technique of Patent Document 1, it is necessary to cool a high-temperature gasified gas from which dusts have been removed by a dust collector to about 40 ° C. in the process of gas purification by a wet gas purification device, for example, in the case of desulfurization. is there. Since it is desirable to supply high-temperature fuel gas to power generation means such as gas turbines and fuel cells that are operated at high temperatures, in general, fuel gas that has been purified in a wet manner uses the heat of gasification gas before purification. Reheat. In the process of heat exchange between the gasified gas and the fuel gas, heat loss occurs, and the amount of loss tends to increase as the temperature adjustment range increases. Therefore, in the technique of Patent Document 1 that needs to be cooled to about 40 ° C., the efficiency of the entire power generation system is reduced due to heat loss accompanying temperature adjustment for gas purification.

  In wet gas purification, power generation efficiency is reduced due to condensation of water vapor in the gasification gas. For example, in a gas cleaning tower which is an example of a wet gas purification apparatus, for example, since it is cleaned at a low temperature of 40 ° C., water vapor contained in the gasification gas is condensed into water, but the heat generated at this time Recovery of certain condensation heat is difficult, and the flow rate of the gasification gas is reduced. Eventually, the energy is discharged out of the system as hot wastewater and does not contribute to power generation.

  Such a problem exists not only when purifying a gasification gas but also when purifying a gas containing a combustible component.

Japanese Patent No. 3764568

  The present invention has been made in view of the above situation, and it is possible to remove impurities from gases produced from various fuels and to purify them into high-temperature gas, and impurities from gases produced from various fuels. An object of the present invention is to provide a highly efficient power generation system equipped with a gas purification facility capable of removing gas and purifying it into a high-temperature gas.

  In order to achieve the above object, a first aspect of the present invention is a wet processing means for removing or reducing water-soluble impurities, condensable impurities and particulate impurities in a gas by washing the gas containing a combustible component in a wet manner. And a dry processing means for removing or reducing gaseous impurities that are not removed by the wet processing means without condensing water vapor contained in the cleaning gas, which is a gas cleaned by the wet processing means, with a remover. It is in the gas purification facility. Here, when “wet the gas containing the combustible component is washed in a wet manner”, it is performed under a temperature condition in which the water vapor contained in the gas is not condensed.

  In the first aspect, a high-temperature purified gas from which impurities have been removed can be obtained by treating a gas containing a combustible component in the order of wet and dry processes. In that process, since water vapor contained in the gas is not condensed, release of condensation heat, which is heat generated during the condensation of water vapor, can be avoided. Thereby, the impurity contained in the gas containing a combustible component can be removed with high efficiency. The purified gas is particularly useful for power generation means as described above.

  Moreover, a part of the water of the cleaning liquid used in the wet processing means is added to the cleaning gas cleaned by the wet processing means as water vapor. The presence of water vapor contained in the gas containing the original combustible component and the newly added water vapor suppress the generation of carbon (C) resulting from the chemical reaction of carbon monoxide (CO), which is the main component. Therefore, it is possible to avoid the precipitation of solid carbon in the piping, the heat exchanger, the reactor, the impurity removing agent, and further the power generation device. Carbon deposition will cause equipment performance degradation and malfunction, and it will be necessary to clean, repair, and replace the carbon deposited equipment after shutting down the equipment. An emergency shutdown of the refining facility and even the entire power generation system equipped with it may occur. Therefore, avoidance of carbon deposition is essential for a system that handles gas containing carbon monoxide. However, since the gas purification system of the present invention has an effect of suppressing carbon deposition, the gas purification equipment and the power generation system as a whole are sound. In addition, the cost and labor required for cleaning, repairing and replacing the equipment can be reduced. The removing agent used in the dry processing means is a generic term for removing impurities contained in a gasification gas such as a desulfurization agent, a halide absorbent, a mercury removing agent, and an ammonia decomposition catalyst by a dry method.

  According to a second aspect of the present invention, in the gas purification facility described in the first aspect, when the cleaning gas is introduced from the wet processing means to the dry processing means, the temperature of the cleaning gas is set to the cleaning temperature. And a temperature maintaining means for maintaining the water vapor contained in the gas so as not to condense.

  In the second aspect, the water vapor contained in the cleaning gas can be more reliably not condensed by the temperature maintaining means.

  According to a third aspect of the present invention, in the gas purification facility according to the first or second aspect, the dry treatment means includes a metal oxide desulfurization agent that chemically reacts with a sulfur compound as the removal agent. It is in the gas purification equipment characterized by including.

  In the third aspect, the sulfur compound can be removed from the gas in a dry manner.

  According to a fourth aspect of the present invention, in the gas purification facility described in the first or second aspect, the dry processing means includes a halogen removing apparatus including a halide absorbent that chemically reacts with a halide as the removing agent. It is in a gas purification facility characterized by containing.

  In the fourth aspect, the halide can be removed from the gas in a dry manner.

  According to a fifth aspect of the present invention, in the gas purification facility described in the first or second aspect, the dry processing means includes a mercury removal apparatus including a mercury absorbent that absorbs mercury as the removal agent. It is in the gas purification facility.

  In the fifth aspect, mercury can be removed from the gas in a dry manner.

  According to a sixth aspect of the present invention, in the gas purification facility according to any one of the first to fifth aspects, the halide is removed from the gas prior to the cleaning of the gas by the wet processing means. In addition, a pre-halogen removing device including a halide absorbent that chemically reacts with a halide is disposed in a gas purification facility.

  In the sixth aspect, it is possible to suppress precipitation of ammonium chloride in the piping or the like before the gas is supplied to the wet processing means. Conventionally, it has been necessary to keep the gas temperature at about 230 ° C. in order to suppress precipitation of ammonium chloride. In the present invention, since the halide is removed, ammonium chloride does not precipitate even if the gas temperature before being supplied to the wet processing means is about 230 ° C. or lower. Accordingly, when heat exchange is performed between the gas before being supplied to the wet processing means and the cleaning gas processed by the wet processing means, the gas before being supplied to the wet processing means is about 230 ° C. or less. Therefore, the temperature of the cleaning gas can be raised higher.

  According to a seventh aspect of the present invention, there is provided a gas supply source for producing a gas, the gas purification facility according to any one of the first to sixth aspects for purifying a gas from the gas supply source, and the gas A power generation system comprising: a gas turbine that obtains power by burning fuel gas purified by a refining facility; and a steam turbine that obtains power by steam generated by heat of exhaust from the gas turbine. .

  In the seventh aspect, since the gaseous impurities are removed by the dry processing means while the water vapor is contained in the gas, the water vapor contained in the gas and the water vapor evaporated by the wet processing means are both at high temperature and high pressure. Since it can be used as the power of the turbine as gas, the power generation output can be improved.

  According to an eighth aspect of the present invention, in the power generation system according to the seventh aspect, the gas supply source is a coal gasification facility that produces coal gasification gas by a reaction of coal and supplies the gas purification facility. The power generation system is characterized by being.

  In the eighth aspect, the refined gas from which impurities contained in the coal gasification gas obtained by gasifying coal is efficiently removed is used as the fuel gas, and the coal gasification combined power generation system that generates power with the gas turbine and the steam turbine is highly efficient. It can generate electricity.

  ADVANTAGE OF THE INVENTION According to this invention, the high temperature refined gas from which the impurity was removed is obtained by processing the gas containing a combustible component in the order of wet and dry. In addition, the gas can be purified without condensing the water vapor originally possessed by the gas and the water vapor added when the gas is washed wet. As a result, the impurities contained in the gas are removed with high efficiency without purifying the heat energy used for the evaporation of moisture during the wet cleaning process, and the gas is purified. In addition, carbon production due to the chemical reaction of carbon monoxide, which is the main component, is suppressed, so that solid carbon is deposited on pipes, heat exchangers, reactors, impurity removers, and power generators. It can be avoided.

  Further, in a power generation system that uses this refined gas as fuel gas, it is possible to use the thermal energy that is discharged outside the system in the prior art, so that highly efficient power generation can be realized.

It is a schematic block diagram of the gas purification equipment which concerns on this invention. 1 is a schematic configuration diagram of a combined coal gasification combined power generation system according to the present invention. It is a schematic block diagram of the gas purification equipment which concerns on this invention. It is a figure which shows the state of the fuel gas in the washing | cleaning process in the gas purification equipment which concerns on this invention. It is a figure which shows the state of the fuel gas in the washing | cleaning process in the wet gas purification equipment which concerns on a prior art. It is a schematic block diagram of the gas purification equipment which concerns on this invention. It is a schematic block diagram of the gas purification equipment which concerns on this invention. It is a schematic block diagram of the gas purification equipment which concerns on this invention.

<Embodiment 1>
FIG. 1 shows a schematic configuration of a gas purification facility according to the present invention.
In this embodiment, a case where impurities are removed from a gasification gas which is an example of a gas containing a combustible component will be described as an example. Hereinafter, the gasified gas cleaned by the wet process is referred to as the cleaning gas, and the entire gas purification equipment, that is, the wet gas and the dry gas gas removed from the gas gas is referred to as the purified gas, which is used in equipment such as a turbine that generates power. The purified gas is referred to as fuel gas.

  The gas purification equipment 1 according to the present embodiment includes a scrubber 10 (wet processing means) that cleans the gasification gas in a wet manner, and water vapor contained in the cleaning gas processed by the scrubber 10 without condensing the gaseous impurities. A desulfurization apparatus 20 (dry treatment means) for removing one sulfur compound with a desulfurizing agent is provided. The scrubber 10 is washed under a temperature condition in which water vapor contained in the gasification gas is not condensed. The subsequent desulfurization apparatus 20 prevents the water vapor contained in the cleaning gas from condensing when removing gaseous impurities.

The gasified gas is introduced into the scrubber 10 from a gas supply source (not shown) outside the gas purification facility 1. The gasification gas, carbon monoxide, in addition to the combustible components such as hydrogen _{(H 2),} carbon dioxide _(CO 2), and water vapor _(H 2 O), nitrogen _{(N 2)} contains further a water-soluble impurities , Condensable impurities, particulate impurities, and gaseous impurities.

  The scrubber 10 is an example of a wet processing means, and cleans the gasification gas in a wet manner. Specifically, the scrubber 10 uses an aqueous solution or the like as a cleaning liquid, introduces a gasification gas into a space in which the cleaning liquid is dispersed, or introduces a gasification gas into the cleaning liquid, so that the water solubility contained in the gasification gas is reduced. Impurities, condensable impurities and particulate impurities are collected in the cleaning liquid and separated.

  By cleaning with the scrubber 10, part or all of the water-soluble impurities, condensable impurities, and particulate impurities are removed from the gasification gas. The water-soluble component is, for example, an alkali metal, ammonia, hydrogen cyanide, or halide. Condensable impurities are, for example, tar and trace substances. The particulate impurities are, for example, dust and char.

  Further, in the scrubber 10, due to the thermal energy of the gasification gas introduced, a part of the water of the cleaning liquid used in the scrubber 10 is evaporated and added to the cleaning gas. For this reason, the cleaning gas in which water vapor is saturated in the outlet temperature condition of the scrubber 10 is obtained.

  The desulfurization apparatus 20 is an example of a dry processing means, and removes or reduces a sulfur compound, which is a kind of gaseous impurity that is not removed by the scrubber 10, without condensing water vapor contained in the cleaning gas. Here, “without condensing the water vapor contained in the cleaning gas” means that the water vapor contained in the cleaning gas is not condensed during the removal of the sulfur compound in the desulfurization apparatus 20, and from the outlet of the scrubber 10. It means that the water vapor contained in the cleaning gas is not condensed even while reaching the desulfurization apparatus 20.

Specifically, the desulfurization apparatus 20 includes a metal oxide desulfurization agent that chemically reacts with a sulfur compound as an example of a removal agent, and the metal oxide desulfurization agent absorbs the sulfur compound in the cleaning gas. Has been. The metal oxide desulfurization agent can remove sulfur compounds such as hydrogen sulfide (H ₂ S) and carbonyl sulfide (COS) to a low concentration.

  In the prior art in which desulfurization is performed only by a wet method, only hydrogen sulfide can be removed. Therefore, a COS converter filled with a catalyst for converting carbonyl sulfide to hydrogen sulfide in advance is required. In contrast, in the present invention, the desulfurization apparatus 20 that performs dry desulfurization can remove both carbonyl sulfide and hydrogen sulfide. Therefore, the gas purification facility 1 does not require a COS converter and simplifies the configuration. be able to.

  The metal oxide desulfurization agent only needs to contain a metal oxide that chemically reacts with a sulfur compound. For example, a desulfurization agent containing iron oxide as a main component, a desulfurization agent containing zinc ferrite as a main component, and an oxidation agent. A desulfurizing agent mainly composed of zinc can be used.

  In the gas purification facility 1 according to the present invention described above, a high-temperature purified gas from which impurities are removed is obtained by processing the gasification gas in the order of wet and dry processes. Further, when the sulfur compound is removed from the cleaning gas by the desulfurizer 20, the water vapor contained in the cleaning gas is prevented from condensing. The cleaning gas from the outlet of the scrubber 10 to the desulfurizer 20 includes water vapor originally contained in the gasification gas and water vapor in which the water in the cleaning liquid has evaporated in the scrubber 10 due to the thermal energy of the gasification gas. ing. The water vapor contained in the cleaning gas is also contained as it is in the purified gas after the sulfur compound is removed by the desulfurization apparatus 20.

  As described above, in the process of removing impurities in the scrubber 10 and the desulfurization apparatus 20, since the water vapor contained in the cleaning gas does not condense, the thermal energy of the gasification gas used to evaporate the moisture in the scrubber 10 is gas. The gasification gas can be purified without being discharged out of the system of the purification facility 1.

  Further, in the gas purification facility 1 according to the present embodiment, the gasification gas is purified by cleaning the gasification gas wet with the scrubber 10 and then using the desulfurization apparatus 20 from the cleaning gas to form sulfur as a kind of gaseous impurities. This is done by removing the compound. In this way, the wet dry cleaning process removes part or all of the water-soluble impurities, condensable impurities, and particulate impurities from the gasification gas, thus simplifying the structure of the subsequent dry processing means. can do.

  Here, when the temperature of the scrubber 10 is higher than the condensation temperature of the water vapor contained in the gasification gas before cleaning, the concentration of the water vapor contained in the cleaning gas is the water vapor of the gasification gas processed by the conventional gas purification equipment. Higher than the concentration of. This is because the water vapor contained in the gasification gas is not condensed and the water contained in the cleaning liquid of the scrubber 10 contains water vapor.

  At this time, in the aqueous shift reaction shown in Formula I, when the concentration of water vapor increases, the reaction tends to proceed from the left side to the right side, that is, in the direction in which carbon monoxide decreases and carbon dioxide increases. . The decrease in carbon monoxide and the increase in carbon dioxide have the effect of hindering the progress of the Butard reaction, which is one of the carbon deposition reactions shown in Formula II, and the effect of suppressing carbon deposition is obtained.

  In this way, the presence of water vapor in the cleaning gas suppresses the production of solid carbon resulting from the chemical reaction of carbon monoxide, which is the main component, so that the piping, heat exchanger, reactor, impurity remover, Can avoid the deposition of carbon in the power generator. Carbon deposition will cause equipment performance degradation and malfunction, and it will be necessary to clean, repair, and replace the carbon deposited equipment after shutting down the equipment. An emergency shutdown of the refinery can also occur. Therefore, avoidance of carbon deposition is an essential matter in a system that handles a gas containing carbon monoxide, but the gas purification system of the present invention has an effect of suppressing carbon deposition, so that the soundness of gas purification equipment is increased. Costs and labor required for cleaning, repairing and replacing equipment can be reduced.

  In addition, since the sulfur compound which is one kind of gaseous impurities is removed by the desulfurization apparatus 20 after the impurities are removed by the wet process by the scrubber 10, the wet processing means includes water-soluble impurities, condensable impurities and particles. A scrubber 10 that removes impurities can be used. That is, in the conventional gas purification equipment, in order to remove gaseous impurities, wet equipment such as a cooling tower, a washing tower, and a desulfurization tower is provided after the high-temperature scrubber. The number of towers, washing towers and desulfurization towers can be reduced, and pressure loss can be reduced. Moreover, since there is no condensation of water vapor in the wet treatment means, the amount of waste water is reduced, and the scale and configuration of the facility for treating the waste water of the gas purification equipment can be made compact.

  In the gas purification facility 1 according to the present embodiment, a venturi scrubber, a jet scrubber, a spray tower, a cyclonic scrubber, or the like can be used as the wet processing means. Further, the dry processing means is not limited to the desulfurization apparatus 20, and other dry processing means can be used as appropriate according to the gaseous impurities to be removed from the cleaning gas.

  For example, as an example of the dry processing means, a halogen removing device including a halide absorbent that chemically reacts with a halide contained in a gasification gas can be exemplified. Specifically, the halide absorbent absorbs halides such as hydrogen chloride (HCl) and hydrogen fluoride (HF) in the gasification gas. As the halide absorbent, those containing alkali aluminate which is a composite oxide of aluminum and an alkaline substance can be used. It is also possible to use a halide absorbent other than the alkali aluminate.

Another example of the dry processing means is an ammonia removal device that removes ammonia (NH ₃ ) contained in the gasification gas. Specifically, a catalyst or the like that directly decomposes or oxidatively decomposes ammonia in the gasification gas can be used.

  Further, as another example of the dry processing means, a mercury removing device that removes mercury (Hg) contained in the gasification gas can be used. Specifically, a copper-based mercury absorbent that absorbs and removes mercury in the gasification gas can be used. It is also possible to use a mercury removing agent other than a copper-based mercury absorbent such as activated carbon.

<Embodiment 2>
FIG. 2 shows a schematic configuration of the combined coal gasification combined power generation system according to the present invention, and FIG. 3 shows a schematic configuration of gas purification equipment constituting the combined coal gasification combined power generation system.

  In the following embodiments, an example in which a coal gasification gas that is an example of a gasification gas is purified to obtain a fuel gas for a gas turbine will be described.

  As shown in FIG. 2, the combined coal gasification combined cycle system I includes a coal gasification facility 2 that produces coal gasification gas using coal as a raw material. The coal gasification facility 2 includes a coal gasification furnace 2A that reacts coal with a gasifying agent, and produces coal gasification gas in the coal gasification furnace 2A. This coal gasification gas contains carbon dioxide, water vapor, and nitrogen in addition to combustible components such as carbon monoxide and hydrogen, and further contains water-soluble impurities, condensable impurities, particulate impurities, and gaseous impurities. It is.

  The coal gasification gas produced in the coal gasification furnace 2 </ b> A is introduced into the dust collector 3. The dust collector 3 is a device that removes dust and coal char contained in the coal gasification gas with a cyclone or a filter. The coal gasification gas collected by the dust collector 3 is introduced into the gas purification facility 1A, impurities are removed by the gas purification facility 1A to become purified gas, and the purified gas is used as fuel gas in the combined power generation facility 4. .

  The combined power generation facility 4 includes a gas turbine 40 that obtains power by expansion of fuel gas combusted in a combustor (not shown). The exhaust gas from the gas turbine 40 is recovered by the exhaust heat recovery boiler 60 and released from the chimney 50 to the atmosphere. Steam is generated in the exhaust heat recovery boiler 60, and the steam generated in the exhaust heat recovery boiler 60 is expanded by the steam turbine 70 to obtain power. The generator 80 is driven by the power of the gas turbine 40 and the steam turbine 70 to generate power.

  For this reason, high-efficiency power generation can be performed by the coal gasification combined power generation system in which the refined gas from which impurities contained in the coal gasification gas are efficiently removed is used as the fuel gas and the gas turbine 40 and the steam turbine 70 generate power.

  The purified gas may be used as a fuel for power generation systems other than the above-described combined power generation facility 4. For example, the refined gas is a fuel of a power generation system including a molten carbonate fuel cell or a solid oxide fuel cell, or a power generation system including a gas engine operated by the fuel gas and a generator activated by the operation of the gas engine. It may be used as The purified gas may be supplied as a raw material for producing hydrogen and methane, a raw material for producing liquid fuels such as methanol and ethanol, and a synthetic raw material for chemical products such as plastic and vinyl.

  The gas purification facility 1A will be described in detail with reference to FIG. As shown in the figure, a gas purification facility 1A includes a scrubber 10 as a wet processing means for cleaning coal gasification gas in a wet manner, a heat exchanger (temperature maintaining means) 15, and a desulfurization apparatus 20 as a dry processing means. The coal gasification gas is supplied from the coal gasification facility 2 (see FIG. 2), and impurities are removed from the coal gasification gas. The purified gas obtained in the gas purification facility 1 is supplied to the gas turbine 40 as fuel gas for the combined power generation facility 4.

  The temperature maintaining means maintains the temperature of the cleaning gas at a temperature condition that does not condense the water vapor contained in the cleaning gas when the cleaning gas is introduced from the scrubber 10 into the desulfurization apparatus 20.

  The temperature maintaining means is a concept including further raising the temperature of the cleaning gas. Therefore, the heat exchanger 15 is an example of a temperature maintaining means in this concept.

  The heat exchanger 15 raises the temperature of the cleaning gas with the heat of the coal gasification gas before being introduced into the scrubber 10 from the coal gasification facility 2. That is, the coal gasification gas from the coal gasification facility 2 is cooled down and introduced into the scrubber 10, and the cleaning gas is heated up and introduced into the desulfurization apparatus 20. The cleaning gas introduced into the desulfurization apparatus 20 has a temperature suitable for removing sulfur compounds.

  In the present embodiment, in the heat exchanger 15, the coal gasification gas from the coal gasification facility 2 is cooled to about 240 ° C., and the cleaning gas cleaned by the scrubber 10 to about 130 ° C. is coal gasified. The temperature of the high-temperature coal gasification gas from the facility 2 is raised to a temperature necessary for the operation of the desulfurization apparatus 20.

  The reason why the temperature of the coal gasification gas is lowered to about 240 ° C. is that when the temperature is about 230 ° C. or less, hydrogen chloride and ammonia in the coal gasification gas react with each other and solid ammonium chloride is remarkably precipitated. . Since ammonium chloride causes clogging and corrosion of the pipe and the heat exchanger 15, it is essential to avoid precipitation thereof. If the coal gasification gas before the wet treatment means is kept at about 240 ° C., ammonium chloride will not be significantly precipitated.

  The scrubber 10 is an example of a wet processing means, and cleans the coal gasification gas in a wet manner. Specifically, the scrubber 10 uses an aqueous solution or the like as a cleaning liquid, introduces a gasification gas into a space in which the cleaning liquid is dispersed, or introduces a gasification gas into the cleaning liquid, so that the water solubility contained in the gasification gas is reduced. Impurities, condensable impurities and particulate impurities are collected in the cleaning liquid and separated.

  By washing with the scrubber 10, a part or all of water-soluble components, condensable impurities, and particulate impurities are removed from the coal gasification gas. The water-soluble component is, for example, an alkali metal, ammonia, hydrogen cyanide, or halide. Condensable impurities are, for example, tar and trace substances. The particulate impurities are, for example, dust and coal char.

  Moreover, in the scrubber 10, a part of the water | moisture content of the washing | cleaning liquid used with the scrubber 10 evaporates with the thermal energy of the coal gasification gas introduce | transduced, and adds to washing gas. For this reason, the cleaning gas in which water vapor is saturated in the outlet temperature condition of the scrubber 10 is obtained.

  The desulfurization apparatus 20 is an example of a dry processing unit, and is an apparatus including a metal oxide desulfurization agent that chemically reacts with a sulfur compound. Specifically, in the desulfurization apparatus 20, the metal oxide desulfurization agent absorbs the sulfur compound in the raw material gas. The metal oxide-based desulfurization agent can remove sulfur compounds such as hydrogen sulfide and carbonyl sulfide to a low concentration.

  In this way, the gas purification facility 1A removes impurities from the coal gasification gas with the scrubber 10 and the desulfurization apparatus 20 to obtain a purified gas.

  Here, the effect of the power generation system including the gas purification facility 1A according to the present embodiment will be described with reference to FIG.

  The coal gasification gas produced by the coal gasification facility 2 includes water vapor 100 (represented by Δ in the figure), water-soluble impurities, condensable impurities, and particulate impurities 200 (represented by ▽ in the figure). ) And gaseous impurities 210 (represented by □ in the figure). Other components of coal gasification gas (hydrogen, carbon monoxide, carbon dioxide, nitrogen, etc.) are represented by cloud symbols.

  The coal gasification gas is introduced into the scrubber 10 and the water-soluble impurities, condensable impurities, and particulate impurities 200 are washed. At this time, the cleaning energy used in the scrubber 10 evaporates due to the thermal energy of the coal gasification gas, and this moisture is added to become saturated as water vapor 110 (represented by a circle in the figure). Gas is obtained. That is, water-soluble impurities, condensable impurities, and particulate impurities 200 are removed from the cleaning gas, and water vapor 110 in the scrubber 10 is newly added.

  The cleaning gas is maintained at a temperature higher than the temperature at which the water vapor 100, 110 is condensed by the heat exchanger (temperature maintaining means) 15, so that the water vapor 100, 110 is introduced into the desulfurization apparatus 20 without being condensed. Is done.

  In the desulfurization apparatus 20, the sulfur compounds exemplified as the gaseous impurities 210 are removed from the cleaning gas with a remover, and purified gas is produced. This purified gas is introduced into the combined power generation facility 4 as fuel gas. The refined gas contains, in addition to combustible components, water vapor 100 contained in the original coal gasification gas and water vapor 110 added in the scrubber 10 cleaning process.

  As described above, in the power generation system including the gas purification facility according to the present invention, the sulfur compound in the gaseous impurities 210 is removed by the desulfurization apparatus 20 while moisture is contained in the coal gasification gas as the water vapor 100, 110. Therefore, both the water vapor 100 contained in the coal gasification gas and the water vapor 110 evaporated in the scrubber 10 can be used for the power of the gas turbine 40, and the power generation efficiency can be improved.

  On the other hand, the wet gas purification equipment according to the prior art cannot realize such an improvement in power generation efficiency. This will be described with reference to FIG. FIG. 5 shows the state of coal gasification gas in the purification process in the wet gas purification facility according to the prior art.

  As shown in FIG. 5, the wet gas purification equipment according to the prior art removes water-soluble impurities, condensable impurities, and particulate impurities by the former wet cleaning means, and mainly the sulfur compounds etc. by the latter wet treatment means. The gaseous impurities are removed. Specifically, the subsequent wet processing means is a wet desulfurization apparatus including a cooling tower, a cleaning tower, a desulfurization tower, and the like that perform desulfurization in a wet manner.

  The coal gasification gas introduced into the wet cleaning means such as the water scrubber in the previous stage includes water vapor 100 (represented by Δ in the figure), water-soluble impurities, condensable impurities, and particulate impurities 200 (in the figure, ▽ ) And gaseous impurities 210 (represented by □ in the figure). Other components of coal gasification gas (hydrogen, carbon monoxide, carbon dioxide, nitrogen, etc.) are represented by cloud symbols.

  The coal gasification gas is introduced into a water scrubber or the like, and water-soluble impurities, condensable impurities, and particulate impurities are washed. At this time, the cleaning gas used in the scrubber 10 evaporates due to the thermal energy of the coal gasification gas, and the cleaning gas added to become saturated as water vapor 110 (represented by ◯ in the figure) is obtained. It is done. That is, water-soluble impurities, condensable impurities, and particulate impurities 200 are removed from the cleaning gas, and water vapor 110 in the scrubber 10 is newly added.

  The cleaning gas is introduced into a wet processing means such as a subsequent wet desulfurization apparatus, and the sulfur compounds exemplified as the gaseous impurities 210 are removed by cleaning. At this time, in the wet desulfurization apparatus or the like, since the cleaning process is performed at a low temperature (about 40 ° C.), the water vapors 100 and 110 saturated in the cleaning gas are condensed. The condensed water vapor is discharged out of the system as warm waste water together with the heat of condensation generated at that time, resulting in heat loss. Furthermore, since the water vapor 100, 110 is removed from the coal gasification gas, the flow rate (volume) of the refined gas is reduced from the initial flow rate of the coal gasification gas.

  As is clear from the comparison between FIG. 4 and FIG. 5, in the power generation system including the gas purification facility according to the present invention, the reduction in heat loss due to the temperature decrease / temperature increase that occurred in the wet gas purification facility according to the prior art. In addition, since the decrease in the gas flow rate can be suppressed, the amount of power generation in the combined power generation facility 4 (see FIG. 2) using purified gas as fuel gas increases. That is, the power generation system including the gas purification facility according to the present invention can generate power more efficiently than the power generation system including the conventional wet gas purification facility.

  In addition, although the coal gasification combined cycle power generation system I described above includes the gas purification facility 1A, the coal gasification combined power generation system I may include the gas purification facility 1 described in the first embodiment. Even in this case, the power generation efficiency can be improved as compared with the conventional wet gas purification equipment.

  In the gas purification facility 1A described above, the temperature maintaining means is not limited to the heat exchanger 15, and a heater such as a steam gas heater or an electric heater for raising the temperature is used for the purpose of raising the temperature of the cleaning gas. it can.

  Further, in the gas purification facility 1A according to the present embodiment, the purification of the coal gasification gas is performed by washing the coal gasification gas by the scrubber 10 and then removing the sulfur compound by the desulfurization apparatus 20 in a dry manner. . As described above, since the water-soluble component, the condensable component, and a part or all of the particulate component are removed from the coal gasification gas by the wet cleaning first, the dry processing means in the latter stage is mainly a gas. It is sufficient to target only the impurities, and the configuration can be simplified.

  In addition, since the sulfur compound which is one kind of gaseous impurities is removed by the desulfurization apparatus 20 after the impurities are removed by the wet process by the scrubber 10, the wet processing means includes water-soluble impurities, condensable impurities and particles. A scrubber 10 that removes impurities can be used. That is, it is possible to reduce the pressure loss by reducing the cooling tower, washing tower, and desulfurization tower required in the conventional gas purification equipment. Further, since there is no condensation of water vapor in the wet treatment means, the amount of waste water is reduced, and the scale and configuration of the facility for treating the waste water of the gas purification equipment (and the entire power generation system including this) can be made compact.

  Hereinafter, Embodiments 3 to 5 show application examples of dry processing means of gas purification equipment.

<Embodiment 3>
FIG. 6 shows a schematic configuration of the gas purification facility 1B according to the present embodiment. In addition, the same code | symbol is attached | subjected to the same thing as Embodiment 2, and the overlapping description is abbreviate | omitted.

  In the gas purification facility 1B, a halogen removing device 21 and a desulfurizing device 20 are arranged as dry processing means.

  The halogen removing device 21 is a device including a halide absorbent that chemically reacts with a halide contained in the coal gasification gas.

  The coal gasification gas is introduced into the desulfurization device 20 after the halide is removed by the halogen removal device 21, and the sulfur compound is removed to become a refined gas.

  Thus, by providing the dry processing means corresponding to the gaseous impurities to be removed, the halide can be surely removed even when the scrubber 10 cannot complete the removal.

<Embodiment 4>
FIG. 7 shows a schematic configuration of a gas purification facility 1C according to the present embodiment. In addition, the same code | symbol is attached | subjected to the same thing as Embodiment 2, and the overlapping description is abbreviate | omitted.

  In the gas purification facility 1C, a mercury removal device 22 and a desulfurization device 20 are arranged as dry processing means.

  As described in the first embodiment, the mercury removing device 22 is a device that absorbs and removes mercury using a mercury absorbent as a removing agent. Mercury removal agents refer to copper-based mercury removal agents, activated carbon, and other removal agents.

  The mercury removing device 22 is disposed between the downstream of the scrubber 10 and the heat exchanger 15. Thus, mercury is removed before the cleaning gas enters the heat exchanger 15.

<Embodiment 5>
FIG. 8 shows a schematic configuration of a gas purification facility 1D according to the present embodiment. In addition, the same code | symbol is attached | subjected to the same thing as Embodiment 2, and the overlapping description is abbreviate | omitted.

  In addition to the scrubber 10 (wet processing means) and the desulfurization apparatus 20 (dry processing means), the gas purification facility 1D includes a pre-halogen between a coal gasification gas supply source (not shown) and the heat exchanger 15. A removing device 23 is provided.

  The pre-halogen removing device 23 is the same device as the halogen removing device 21 described in the first or second embodiment. The pre-halogen removing device 23 removes hydrogen chloride contained in the coal gasification gas introduced into the scrubber 10. Thereby, hydrogen chloride used as a raw material of ammonium chloride can be removed from the coal gasification gas during the period from the pre-halogen removing device 23 to the scrubber 10.

  Since the production reaction of ammonium chloride proceeds remarkably at about 230 ° C. or less, in Embodiment 1 where the coal gasification gas contains hydrogen chloride and ammonia, the outlet of the heat exchanger 15 needs to be kept at the temperature or higher.

  However, in the gas purification facility 1D according to the present embodiment, hydrogen chloride is previously removed from the coal gasification gas by the pre-halogen removal device 23, so that ammonium chloride in the coal gasification gas before being cleaned by the scrubber 10 is reduced. Not generated.

  Therefore, in the heat exchanger 15, the coal gasification gas processed with the pre-halogen removal apparatus 23 can be made into about 230 degreeC or less. For this reason, the heat energy recovered when the coal gasification gas is lowered to about 230 ° C. or less (for example, about 140 ° C.) by the heat exchanger 15 can be effectively used for raising the temperature of the cleaning gas.

  The gas refining equipment 1D is assumed to be applied to the combined coal gasification combined power generation system described in the second embodiment, but may purify other gases other than the coal gasification gas. The gas may be applied to uses other than that used as fuel gas.

<Other embodiments>
Although Embodiment 2-Embodiment 5 mentioned above illustrated and demonstrated coal gasification gas as gas containing a combustible component, the gas purification equipment which concerns on this invention is not restricted to the case where coal gasification gas is refine | purified. That is, gas includes gas, such as coal, heavy oil, biomass, waste, solid waste fuel (Refuse Delivered Fuel, RDF), solid fuel made of waste paper and waste plastic (Refuse Paper and Plastic Fuel, RPF), etc. Can be purified. Moreover, the gas purification equipment according to the present invention can also purify off-gas produced as a by-product in a chemical plant and off-gas produced as a by-product during the purification of crude oil.

  INDUSTRIAL APPLICABILITY The present invention can be used in an industrial field for purifying a gas containing a combustible component and an industrial field in which power generation or the like is performed using the purified gas.

I Coal gasification combined power generation system 1, 1A, 1B, 1C, 1D Gas refining equipment 2 Coal gasification equipment 2A Coal gas furnace 3 Dust collector 4 Combined power generation equipment 10 Scrubber 15 Heat exchanger 20 Desulfurization equipment 21 Halogen removal equipment 22 Mercury removal device 23 Pre-halogen removal device 40 Gas turbine 50 Chimney 60 Waste heat recovery boiler 70 Steam turbine 80 Generator 100, 110 Water vapor 200 Water-soluble impurities, condensable impurities and particulate impurities 210 Gaseous impurities

Claims (8)

Wet processing means for cleaning a gas containing a combustible component in a wet manner to remove or reduce water-soluble impurities, condensable impurities and particulate impurities in the gas;
A dry processing means for removing or reducing gaseous impurities that are not removed by the wet processing means without condensing water vapor contained in the cleaning gas, which is a gas cleaned by the wet processing means, with a remover. Gas purification equipment. In the gas purification facility according to claim 1,
A temperature maintaining means for maintaining the temperature of the cleaning gas at a temperature at which water vapor contained in the cleaning gas is not condensed when the cleaning gas is introduced from the wet processing means into the dry processing means. Gas purification equipment. In the gas purification equipment according to claim 1 or 2,
The gas purification equipment characterized in that the dry processing means includes a desulfurization apparatus including a metal oxide desulfurization agent that chemically reacts with a sulfur compound as the removal agent. In the gas purification equipment according to claim 1 or 2,
The gas purification equipment characterized in that the dry processing means includes a halogen removing device including a halide absorbent that chemically reacts with a halide as the removing agent. In the gas purification equipment according to claim 1 or 2,
The gas purification facility, wherein the dry processing means includes a mercury removing device including a mercury absorbent that absorbs mercury as the removing agent. In the gas purification facility according to any one of claims 1 to 5,
Prior to the cleaning of the gas by the wet processing means, a pre-halogen removal device including a halide absorbent that chemically reacts with the halide is disposed so that the halide is removed from the gas. Gas purification equipment. A gas source from which the gas is produced;
The gas purification equipment according to any one of claims 1 to 6, wherein the gas from the gas supply source is purified.
A gas turbine that obtains power by burning the fuel gas purified by the gas purification facility;
A power generation system comprising: a steam turbine that obtains power by steam generated by heat of exhaust gas from the gas turbine. The power generation system according to claim 7,
The power generation system according to claim 1, wherein the gas supply source is a coal gasification facility that produces coal gasification gas by a reaction of coal and supplies the gas to the gas purification facility.