Title of invention: Gas purification apparatus
Technical field
[0001]
　The present disclosure relates to a gas purification apparatus.
Background technology
[0002]
　In an integrated coal gasification combined cycle plant, the produced gas obtained by gasifying coal is hydrogen sulfide using an aqueous amine solution in a hydrogen sulfide absorption tower after ammonia (NH 3 ) is removed in an ammonia removing unit, for example, a washing tower. It is purified by removing (H 2 S). In Patent Documents 1 and 2, NH 3 removed by a washing tower can be obtained as off-gas by a stripper, burned in a reducing atmosphere by a combustion device, and H 2 S removed by a hydrogen sulfide absorption tower is described. , It is described that it is burned as off-gas by a combustion device in an oxidizing atmosphere.
Prior art literature
Patent documents
[0003]
Patent Document 1: Japanese Patent No. 3924150
Patent Document 2: Japanese Patent Application Laid-Open No. 2004-36983
Outline of the invention
Problems to be solved by the invention
[0004]
　However, in the gas purification apparatus described in Patent Documents 1 and 2, since the removal of NH 3 is performed only in the water washing tower, it is assumed that the NH 3 is completely removed in the water washing tower. There is a problem that the height of the tower becomes high (the size of the ammonia removing part becomes large) and the cost of the gas purification device increases. If, NH in the washing tower 3 if not completely removed can, NH was not removed 3 flows into the hydrogen sulfide absorption tower, H 2 since been recovered in the aqueous amine solution with S becomes off, H 2 S and A processing facility for a mixed gas of NH 3 is required, which increases the cost of the gas purification device.
[0005]
　In view of the above circumstances, at least one embodiment of the present disclosure is intended to provide a gas purification apparatus capable of reducing the size of the ammonia removing portion.
Means to solve problems
[0006]
　The gas purification device according to at least one embodiment of the present invention is a gas purification device that purifies a first gas containing ammonia and hydrogen sulfide, and removes a part of ammonia contained in the first gas from the first gas. Hydrogen sulfide and ammonia are removed from the ammonia removing part, the first off gas recovery part that recovers the first off gas containing the ammonia removed by the ammonia removing part, and the second gas from which a part of ammonia is removed by the ammonia removing part. Combustion that burns the first off-gas and the second off-gas, the hydrogen sulfide / ammonia removal section to be removed, the second off-gas recovery section that recovers the second off-gas containing hydrogen sulfide and ammonia removed by the hydrogen sulfide / ammonia removal section, and the second off-gas recovery section. The combustion unit includes a first combustion chamber in which combustion is performed in a reducing atmosphere, a second combustion chamber in which combustion is performed in a reducing atmosphere on the downstream side of the first combustion chamber, and a second combustion unit. It includes a third combustion chamber in which combustion is performed in an oxidizing atmosphere on the downstream side of the chamber, and the first off-gas flows into the first combustion chamber and the second off-gas flows into the third combustion chamber. There is.
[0007]
　According to this configuration, NH from the first gas by the ammonia removal unit 3 without completely removing the, NH remaining in the second gas 3 the H in the combustion unit 2 so can be processed together with S, By reducing the removal rate of NH 3 , the size of the ammonia removing part can be reduced.
[0008]
　In some embodiments, the second gas may contain 2 ppm or more of ammonia. NH 3 remaining in the second gas without being removed by the ammonia removing unit is contained in the second off-gas and is burned in an oxidizing atmosphere in the third combustion chamber. Then, NH 3 burns and nitrogen oxides (NOx) are generated. However, by adjusting the concentration of NH 3 remaining in the second gas to about 2 ppm or more, the amount of NOx derived from NH 3 remaining in the ammonia removing part can be reduced as much as possible, so that the amount of NOx generated can be increased. While suppressing it, the size of the ammonia removing part can be reduced.
[0009]
　In some embodiments, the removal rate of ammonia removed from the first gas may be 98% or less. When the removal rate is close to 100%, the size required for the ammonia removing part rapidly increases as the removal rate increases. Therefore, by suppressing the removal rate at which NH 3 is removed from the first gas to 98% or less, the size of the ammonia removing part can be reduced while suppressing an increase in the amount of NOx derived from NH 3 remaining in the ammonia removing part. It can be made smaller.
[0010]
　In some embodiments, a portion of the second off-gas may also be configured to flow into the second combustion chamber. According to this configuration, NH 3 is burned in a reducing atmosphere in the second combustion chamber, so that NOx is hardly generated. Therefore, since NH 3 burned in the third combustion chamber is reduced, the size of the ammonia removing portion can be reduced while further suppressing the increase in the amount of NOx derived from NH 3 remaining in the ammonia removing portion. ..
[0011]
　In some embodiments, a denitration section for denitration of the exhaust gas flowing out of the third combustion chamber may be further provided. According to this configuration, even if NOx is generated by the combustion of NH 3 in the third combustion chamber , at least a part of NH 3 is decomposed into nitrogen and water in the denitration part, so that the NOx flowing out from the gas purification apparatus since the total amount is reduced, NH remaining ammonia removal unit 3 while further suppressing the increase in the amount of NOx generated from, it is possible to reduce the size of the ammonia removal unit.
[0012]
　In some embodiments, a transducer that produces a first gas by hydrolyzing hydrogen cyanide and carbonyl sulfide contained in the product gas obtained by gasifying coal may be further provided. According to this configuration, the size of the ammonia removing section can be reduced in the integrated coal gasification combined cycle plant.
Effect of the invention
[0013]
　According to at least one embodiment of the present disclosure, NH from the first gas in ammonia removal unit 3 without completely removing the, NH remaining in the second gas 3 H the combustion unit 2 can be processed with S Therefore, the size of the ammonia removing part can be reduced by lowering the removal rate of NH 3 in the ammonia removing part.
A brief description of the drawing
[0014]
FIG. 1 is a schematic configuration diagram of a gas purification apparatus according to a first embodiment of the present disclosure.
FIG. 2 is a schematic configuration diagram of a combustion portion of the gas purification apparatus according to the first embodiment of the present disclosure.
[Figure 3] NH in water scrubber gas purifying apparatus according to a first embodiment of the present disclosure 3 is a graph schematically showing a relationship between the removal rate and the height of the water washing tower.
FIG. 4 is a schematic configuration diagram of a combustion portion of the gas purification apparatus according to the second embodiment of the present disclosure.
FIG. 5 is a schematic configuration diagram of a gas purification apparatus according to a third embodiment of the present disclosure.
Mode for carrying out the invention
[0015]
　Hereinafter, some embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention to that, but are merely explanatory examples.
[0016]
(Embodiment 1)
　FIG. 1 shows a gas purification apparatus 1 according to the first embodiment of the present disclosure. The gas refining device 1 is a device for refining the produced gas obtained by gasifying coal in the gasification furnace 100 of the integrated coal gasification combined cycle plant. More specifically, the gas purification apparatus 1 adds water to COS and HCN in a converter 2 filled with a catalyst for hydrolyzing both carbonyl sulfide (COS) and hydrogen cyanide (HCN) contained in the produced gas. This is a device for removing H 2 S and NH 3 from the first gas containing H 2 S and NH 3 produced by decomposition .
[0017]
　The gas purification device 1 separates the NH 3 by gas-liquid separation between the water washing tower 3 which is an ammonia removing part for removing a part of NH 3 from the first gas and the waste water in which NH 3 removed by the water washing tower 3 is dissolved. H 2 S and NH 3 are amineed from the stripper 4, which is the first off-gas recovery unit for recovering the first off-gas containing the above, and the second gas produced by removing a part of NH 3 from the first gas in the washing tower 3. and hydrogen sulfide ammonia absorption tower 5 is a hydrogen sulfide-ammonia removal unit for removing by absorption to absorb liquid such as an aqueous solution, H absorbed in the absorption liquid 2 S and NH 3 the recovered second offgas comprising It includes an absorption / regeneration tower 6 which is a 2 off-gas recovery unit, and a combustion device 7 which is a combustion unit that burns the first off-gas and the second off-gas. Since the gas refining apparatus 1 according to the first embodiment is an apparatus for purifying the produced gas obtained by gasifying coal in the gasification furnace 100 of the integrated coal gasification combined cycle plant, the converter 2 is also gas refined. This is a constituent requirement of the device 1.
[0018]
　The gas purification device 1 can further include a wastewater treatment device 11 for treating gas-liquid separated wastewater in the stripper 4. The wastewater treatment device 11 is configured to separate the HCN that has not been converted by the converter 2 from the wastewater from the stripper 4 and send it to the combustion device 7. The combustion device 7 communicates with the flue gas desulfurization device 12 for desulfurizing the exhaust gas of the combustion device 7 via the pipe 14. The flue gas desulfurization apparatus 12 communicates with the chimney 13 via the pipe 15.
[0019]
　Further, in order to heat the refined gas generated from the gasifier 100 by the gas purification apparatus 1 and flowing out from the hydrogen sulfide / ammonia absorption tower 5, heat is generated between the gasifier 100 and the converter 2. A heat exchanger 103 may be provided between the converter 2 and the washing tower 3 as well as the exchanger 102. The refined gas heated in the heat exchangers 102 and 103 is sent to the gas turbine 101 of the integrated coal gasification combined cycle power plant.
[0020]
　As shown in FIG. 2, the combustion device 7 is divided into a first combustion chamber 7a, a second combustion chamber 7b, and a third combustion chamber 7c from the upstream side to the downstream side. A burner 8 is provided in the first combustion chamber 7a, and the burner 8 is configured to supply fuel and air respectively. Further, the first combustion chamber 7a is configured to supply the first off-gas from the stripper 4 (see FIG. 1) and the HCN from the wastewater treatment device 11 (see FIG. 1). The second combustion chamber 7b is configured to be supplied with air. The third combustion chamber 7c is configured to supply the second off-gas and air from the absorption / regeneration tower 6 (see FIG. 1). The third combustion chamber 7c communicates with the exhaust heat boiler 9, and the exhaust heat boiler 9 communicates with the flue gas desulfurization apparatus 12 (see FIG. 1) via the pipe 14.
[0021]
　Next, the operation of the gas purification apparatus 1 according to the first embodiment will be described.
　As shown in FIG. 1, the generated gas from the gasifier 100 is cooled by heat exchange with the refined gas in the heat exchanger 102 and flows into the converter 2. The converter 2, COS and HCN in the product gas is hydrolyzed by the catalyst, H 2 S and NH 3 first gas containing flows out from the transducer 2. The first gas flowing out of the converter 2 is cooled by exchanging heat with the refined gas in the heat exchanger 103 and flows into the flush tower 3.
[0022]
　In the flush tower 3, the first gas is cooled by coming into contact with water, and the ammonia NH 3 in the first gas is absorbed by the water, so that the NH 3 is removed from the first gas . At this time, NH 3 is not completely removed from the first gas , but a part of NH 3 is removed. The concentration of NH 3 remaining in the second gas flowing out of the washing tower 3 is 2 ppm or more, preferably 5 ppm or more, more preferably 10 ppm or more, and most preferably 10 to 50 ppm. By preventing the washing tower 3 from completely removing NH 3 in this way, the size of the ammonia removing portion can be reduced, that is, the height of the washing tower 3 can be lowered. This effect will be described below.
[0023]
　FIG. 3 schematically shows the relationship between the NH 3 removal rate and the height of the flush tower 3 in the flush tower 3. The NH 3 removal rate on the horizontal axis in FIG. 3 is the ratio of the amount of NH 3 contained in the wastewater flowing out of the washing tower 3 to the amount of NH 3 flowing into the washing tower 3 . Further, the dimensionless height of the washing tower 3 on the vertical axis in FIG. 3 is necessary to obtain an arbitrary NH 3 removal rate with respect to the height of the washing tower 3 required for the NH 3 removal rate to be 100%. It is the ratio of the height of the washing tower 3. NH 3 in the range removal rate of 95 ~ 100%, NH of the range below 3 as compared with the removal rate, NH 3 increase in dimensionless height of the water washing tower 3 with increasing removal rate is dramatically increased. Therefore, the height of the flush tower 3 can be dramatically reduced by slightly reducing the NH 3 removal rate from 100%. For example, by setting the NH 3 removal rate to 98% or less, the height of the flush tower 3 can be reduced to 70% or less as compared with the case where the NH 3 removal rate is 100%, and the cost of the gas purification device 1 can be reduced. Can be reduced. In this way, the height of the flush tower 3 is NH 3 in the flush tower 3. Since it is related to the removal rate, the height of the flush tower 3 can be designed in consideration of the processing capacity of NH 3 in the equipment downstream of the flush tower 3 in the gas purification apparatus 1 .
[0024]
　As shown in FIG. 1, the water that has absorbed NH 3 in the flush tower 3 flows out of the flush tower 3 as drainage and flows into the stripper 4. In the stripper 4, the wastewater is separated into gas and liquid, so that the first off-gas containing NH 3 and the waste water from which NH 3 has been removed flow out from the stripper 4. The first off-gas is sent to the combustion device 7, and the waste water is sent to the wastewater treatment device 11. In the wastewater treatment device 11, the HCN remaining in the wastewater is separated, and the HCN is sent to the combustion device 7.
[0025]
The second gas generated by removing 　NH 3 from the first gas in the washing tower 3 flows out from the washing tower 3 and flows into the hydrogen sulfide / ammonia absorption tower 5. In the hydrogen sulfide / ammonia absorption tower 5, the second gas comes into contact with an absorption liquid such as an aqueous amine solution, and H 2 S and NH 3 in the second gas dissolve in the absorption liquid, so that the second gas becomes H 2 S. And NH 3 are removed. H from the second gas 2 S and NH 3 purification gas is produced are removed flows out from the hydrogen sulfide-ammonia absorption tower 5, the first gas and the generated gas and heat exchange in the respective heat exchangers 103 and 102 Is heated and flows into the gas turbine 101.
[0026]
　H hydrogen sulfide-ammonia absorption tower 5 2 S and NH 3 absorption liquid which has absorbed, by being heated in the absorption regenerator 6, H 2 is reproduced S eliminated. The H 2 S desorbed from the absorption liquid is recovered so as to be contained in the second off gas, and the second off gas is sent to the combustion device 7.
[0027]
　As shown in FIG. 2, in the combustion apparatus 7, in the first combustion chamber 7a, fuel and air are introduced from the burner 8 and combustion is performed in a reducing atmosphere. The first combustion chamber 7a, NH 3 and a first off-gas contains, waste water treatment apparatus 11 because the HCN from (see FIG. 1) is supplied, NH 3 is combusted in a reducing atmosphere of nitrogen and water HCN is burned in a reducing atmosphere to nitrogen, water, and carbon dioxide.
[0028]
　Further, in the third combustion chamber 7c, combustion is performed in an oxidizing atmosphere. Since the second off-gas containing H 2 S and NH 3 is supplied to the third combustion chamber 7c , H 2 S is burned in an oxidizing atmosphere to form sulfur dioxide and water, and NH 3 becomes an oxidizing atmosphere. Is burned to NOx and water. NH in the second off-gas 3 , as described above, completely NH in washing column 3 (see FIG. 1) 3 NH remaining in the second gas to not remove the 3 is. In the gas purifying apparatus 1, completely NH in water scrubber 3 3 without removing, NH remaining in the second gas in the washing tower 3 3 a can be burned and removed in the combustion device 7.
[0029]
　However, when the NH 3 remaining in the second gas in the washing tower 3 is burnt and removed in the combustion device 7, NOx is generated by the combustion of the NH 3 in the oxidizing atmosphere. In the first embodiment, since the concentration of NH 3 remaining in the second gas is about 2 ppm or more, the amount of NOx derived from NH 3 remaining in the second gas in the flush tower 3 is reduced as much as possible. be able to. Therefore, in the gas purification apparatus 1, the height of the flush tower 3 can be lowered while suppressing an increase in the amount of NOx generated.
[0030]
　The exhaust gas from the combustion device 7 is cooled in the exhaust heat boiler 9 and then flows through the pipe 14. As shown in FIG. 1, the exhaust gas is desulfurized in the flue gas desulfurization apparatus 12 after flowing through the pipe 14. The desulfurized exhaust gas is discharged from the chimney 13 into the atmosphere after flowing through the pipe 15.
[0031]
　Thus, from the first gas washing tower 3 NH 3 without completely removing the, NH remaining in the second gas 3 the H in the combustion device 7 2 so can be processed together with S, By lowering the NH 3 removal rate, the height of the flush tower 3 can be lowered. As a result, the cost of the gas purification apparatus 1 can be reduced.
[0032]
(Embodiment 2)
　Next, the gas purification apparatus according to the second embodiment will be described. The gas refining apparatus according to the second embodiment is a modification of the first off-gas processing mode in the combustion apparatus 7. In the second embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.
[0033]
　As shown in FIG. 4, a part of the second off-gas flows into the second combustion chamber 7b, and the rest of the second off-gas flows into the third combustion chamber 7c. Other configurations are the same as those in the first embodiment.
[0034]
　In the second combustion chamber 7b, NH 3 is burned in a reducing atmosphere, so that NOx is hardly generated. Therefore, since NH 3 burned in the third combustion chamber 7c is reduced, the increase in the amount of NOx derived from NH 3 remaining in the washing tower 3 is further suppressed as compared with the first embodiment , and the washing tower 3 is used. The height of the can be lowered.
[0035]
(Embodiment 3)
　Next, the gas purification apparatus according to the third embodiment will be described. The gas purification apparatus according to the third embodiment has a denitration section for denitration of exhaust gas added to each of the first and second embodiments. Hereinafter, the third embodiment will be described with a configuration in which the denitration portion is added to the configuration of the first embodiment, but the third embodiment may be configured by adding the denitration portion to the configuration of the second embodiment. In the third embodiment, the same reference numerals as those of the constituent requirements of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.
[0036]
　As shown in FIG. 5, the pipe 14 is provided with a denitration device 20 which is a denitration portion for denitration of the exhaust gas from the combustion device 7. The denitration device 20 is filled with a known catalyst for decomposing NOx into nitrogen and water. Other configurations are the same as those in the first embodiment.
[0037]
　As described in the first embodiment, NOx is generated by the combustion of NH 3 in the third combustion chamber 7c (see FIG. 2) . However, in the third embodiment, at least a part of the NOx contained in the exhaust gas is decomposed into nitrogen and water in the denitration device 20, so that the total amount of NOx flowing out from the gas purification device 1 is reduced as compared with the first embodiment. .. Therefore, the height of the flush tower 3 can be lowered while further suppressing the increase in the amount of NOx derived from NH 3 remaining in the second gas in the flush tower 3.
[0038]
　In the first to third embodiments, the gas refining apparatus 1 has been described as a part of the integrated coal gasification combined cycle power plant, but the present invention is not limited to this embodiment, and the gas refining apparatus 1 can be provided in any equipment. In this case, the gas purifying apparatus 1 may not have necessarily the converter 2, the gas purifying system 1, (H first gas discharged from any equipment 2 S and NH 3 purifying gas containing) It may be a device for
Code description
[0039]
1 Gas purification device
2 Converter
3 Water washing tower (ammonia removal part)
4 Stripper (1st off gas recovery part)
5 Hydrogen sulfide / ammonia absorption tower (hydrogen sulfide / ammonia removal part)
6 Absorption regeneration tower (2nd off gas recovery part)
7 Combustion device (combustion section)
7a 1st combustion chamber
7b 2nd combustion chamber
7c 3rd combustion chamber
8 Burner
9 Exhaust heat boiler
11 Wastewater treatment device
12 Smoke exhaust desulfurization device
13 Chimney
14 Piping
15 Piping
20 Denitration device (denitration section)
100 Gasifier
101 Gas turbine
102 Heat exchanger
103 Heat exchanger
The scope of the claims
[Claim 1]
　A gas purifying apparatus for purifying ammonia and a first gas containing hydrogen sulphide,
　and ammonia removal unit for removing a portion of the ammonia contained in the first gas from the first gas,
　it is removed by the ammonia removal unit and a first off-gas recovery unit for recovering the first off-gas containing ammonia,
　and the ammonia removal unit second removing hydrogen sulfide and ammonia from the gas hydrogen sulfide ammonia removal unit partially removing ammonia,
　the a second off-gas recovery unit for recovering the second off-gas containing hydrogen sulfide and ammonia removed in the hydrogen sulfide-ammonia removal unit,
　and a combustion section for combusting the first off-gas and the second off-gas
comprises a,
　the combustion unit Is a
　first combustion chamber where combustion is performed in a
　reducing atmosphere, a second combustion chamber where combustion is performed in a reducing atmosphere on the downstream side of the first combustion chamber, and a downstream side of
　the second combustion chamber. It
includes a third combustion chamber in which combustion is performed in an oxidizing atmosphere , and
　the first off-gas flows into the first combustion chamber and the second off-gas flows into the third combustion chamber. Gas purification equipment.
[Claim 2]
　The gas purification apparatus according to claim 1, wherein the second gas contains 2 ppm or more of ammonia.
[Claim 3]
　The gas purification apparatus according to claim 1 or 2, wherein the removal rate at which ammonia is removed from the first gas is 98% or less.
[Claim 4]
　The gas purification apparatus according to any one of claims 1 to 3, wherein a part of the second off-gas also flows into the second combustion chamber.
[Claim 5]
　The gas purification apparatus according to any one of claims 1 to 4, further comprising a denitration portion for denitration of the exhaust gas flowing out of the third combustion chamber.
[Claim 6]
　The gas purification according to any one of claims 1 to 5, further comprising a converter that produces the first gas by hydrolyzing hydrogen cyanide and carbonyl sulfide contained in the produced gas obtained by gasifying coal. apparatus.