JP2020147478A - Ammonia decomposition equipment, gas turbine plant with the same, ammonia decomposition method - Google Patents

Abstract

To suppress an equipment cost of a turbine plant using gas obtained in decomposition of ammonia as fuel.SOLUTION: Ammonia decomposition equipment X comprises a bleed air line 85, an ammonia supply line 81 in which ammonia flows, an ammonia decomposition apparatus 50, and a processed-gas supply line 82. A part of compressed air produced by an air compressor 11a of a gas turbine 11 flows as bleed air BA in the bleed air line 85. The ammonia decomposition apparatus 50 combusts a part of ammonia coming from the ammonia supply line 81 using the bleed air BA coming from the bleed air line 85 as an oxidant and thus subjects ammonia to self thermal decomposition to produce a processed gas PG including hydrogen and nitrogen. The processed-gas supply line 82 leads the processed gas PG as fuel to a combustion chamber 11b of the gas turbine 11.SELECTED DRAWING: Figure 1

Description

The present invention relates to an ammonia decomposition facility for decomposing ammonia, a gas turbine plant equipped with the facility, and an ammonia decomposition method.

In order to reduce CO ₂ emissions in order to protect the global environment, using hydrogen, which does not emit CO ₂ even when burned, is a promising option. However, hydrogen is not easy to transport and store, for example, as compared to fuels such as liquefied natural gas, which are widely used as fuels for gas turbines. Therefore, it is being considered to use ammonia that can be converted into hydrogen as a fuel.

The following Patent Document 1 describes a gas turbine plant provided with a decomposition apparatus for heating ammonia and decomposing the ammonia into hydrogen and nitrogen. This gas turbine plant is equipped with a gas turbine and an exhaust heat recovery boiler. The exhaust heat recovery boiler has a first heat exchange unit that heats water with exhaust gas from a gas turbine to make steam, and a second heat exchange unit that heats liquid ammonia with exhaust gas. In the second heat exchange section, the liquid ammonia boosted by the pump and the exhaust gas exhausted from the gas turbine are exchanged for heat to heat the ammonia, and this ammonia is thermally decomposed to decompose hydrogen and nitrogen. Make it gas. The above-mentioned decomposition device has this second heat exchange section. The decomposed gas is directly guided to the combustor of the gas turbine.

Further, Patent Document 2 below also describes a gas turbine plant provided with a heating device that heats ammonia and decomposes the ammonia into hydrogen and nitrogen. This gas turbine plant is equipped with a gas turbine, a heating device, and an exhaust heat recovery boiler. The exhaust heat recovery boiler heats the water into steam by exchanging heat between a part of the exhaust gas exhausted from the gas turbine and water. The heating device heat-exchanges the rest of the exhaust gas exhausted from the gas turbine with liquid ammonia to heat the ammonia and thermally decompose the ammonia into a decomposed gas containing hydrogen and nitrogen. This decomposed gas is introduced into the combustor of the gas turbine.

Japanese Unexamined Patent Publication No. 04-342829 JP-A-2018-0776794

In the technique described in Patent Document 1, the exhaust has a first heat exchange unit that heats water with exhaust gas from a gas turbine to make steam, and a second heat exchange unit that heats liquid ammonia with exhaust gas. It is necessary to newly design and manufacture a heat recovery steam generator. Further, in the technique described in Patent Document 2, a heating device that heats ammonia with a part of the exhaust gas from the gas turbine and an exhaust heat recovery boiler that heats water with the rest of the exhaust gas are newly designed. It is necessary to manufacture these.

That is, in the technique described in Patent Document 1 and the technique described in Patent Document 2, a device for heating ammonia with exhaust gas from a gas turbine is designed and manufactured, and a part related to this device is also newly designed and manufactured. There is a need to.

Therefore, the technique described in Patent Document 1 and the technique described in Patent Document 2 have a problem that the cost of new design and manufacture of gas turbine plant equipment is high.

Therefore, an object of the present invention is to provide a technique capable of suppressing the equipment cost of a gas turbine plant using a gas obtained by decomposing ammonia as a fuel.

The ammonia decomposition equipment as one aspect of the invention for achieving the above object is
A gas turbine having a compressor that compresses air, a combustor that burns fuel in compressed air that is the air compressed by the compressor to generate combustion gas, and a turbine that is driven by the combustion gas. In the connected ammonia decomposition facility, the bleed air line connected to the gas turbine and a part of the compressed air flows as bleed air, the ammonia supply line through which ammonia flows, the bleed air line and the ammonia supply line. A treated gas that is connected and uses the bleed air from the bleed air line as an oxidizing agent to burn a part of the ammonia from the ammonia supply line to self-decompose the ammonia to contain hydrogen and nitrogen. The gas is provided with an ammonia decomposition device for producing the gas, and a processed gas supply line for guiding the processed gas generated by the ammonia decomposition device to the combustor as the fuel.

In this embodiment, the treated gas containing hydrogen obtained by decomposing ammonia is used as fuel for the combustor. Therefore, carbon dioxide emissions can be reduced as compared with a plant that uses only natural gas as fuel for the combustor. In order to thermally decompose ammonia, it is necessary to supply the heat of reaction required for the decomposition reaction, but as a heat supply method, an external heating method that heats the ammonia by heat transfer from a heat source other than the ammonia to be decomposed, There is a self-pyrolysis method in which a part of the ammonia to be decomposed is burned to generate heat and the remaining ammonia is heated. In the external heating method, when the exhaust gas from the gas turbine or the heat medium heated by the heat of this exhaust gas is used as the heat required for the thermal decomposition of ammonia, the exhaust gas or the heat medium is used as the ammonia decomposer. It is necessary to newly design and manufacture the equipment to guide and the exhaust heat recovery boiler that separately generates this heat medium. On the other hand, in this embodiment, the heat required for the thermal decomposition of ammonia is obtained by a self-thermal decomposition method in which a part of ammonia is burned. Therefore, in this embodiment, the equipment for guiding the exhaust gas and the heat medium to the ammonia decomposer, the exhaust heat recovery boiler for separately generating the heat medium, and the like are not required, and the equipment cost of the gas turbine plant can be suppressed. Further, in this embodiment, even when remodeling work is performed to add ammonia decomposition equipment to the existing gas turbine combined cycle plant, the exhaust heat recovery boiler contained in this plant can be used with almost no remodeling, so that the equipment cost can be suppressed. be able to.

When pyrolyzing ammonia by the self-pyrolysis method, bleed air, which is a part of compressed air generated by the air compressor of a gas turbine, is used as an oxidant for burning a part of ammonia in this embodiment. To do. In order to supply the oxidant to the ammonia decomposition device, it is necessary to have the power to pressurize and supply the fluid containing oxygen above the pressure of the ammonia decomposition device. Therefore, in this embodiment, the equipment cost of the gas turbine plant can be suppressed as compared with the case where the compressed air generated by the air compressor of the gas turbine is not used.

Since the hydrogen-based gas obtained by decomposing ammonia has a smaller calorific value per volume than the natural gas fuel, the volumetric flow rate of the fuel becomes large when used as a gas turbine fuel. As a result, the flow rate of gas flowing through the turbine of the gas turbine increases, and the risk of abnormal events such as surges in the air compressor of the gas turbine increases.

In this embodiment, since the bleed air that is a part of the compressed air generated by the air compressor of the gas turbine is used, the flow rate of the combustion air supplied to the combustor is reduced. Therefore, in this embodiment, the amount of increase in the gas flow rate flowing through the turbine of the gas turbine is small as compared with the self-pyrolysis method that does not use the compressed air generated by the air compressor of the gas turbine and the external heating method. Therefore, in this embodiment, the risk of abnormal events such as surges in the gas turbine air compressor is reduced as compared with the self-thermal decomposition method or the external heating method that does not use the compressed air generated by the gas turbine air compressor. can do. Further, in this embodiment, as compared with other methods, the matching between the gas flow rate flowing through the air compressor of the gas turbine and the gas flow rate flowing through the turbine of the gas turbine is improved, and the thermal performance is improved.

Here, in the ammonia decomposition facility of the above aspect, an ammonia booster provided in the ammonia supply line and boosting the ammonia flowing through the ammonia supply line to a pressure higher than the pressure in the combustor, and the bleed air line. The bleed air booster, which is provided in the above and pressurizes the bleed air flowing through the bleed air line to a pressure higher than the pressure in the combustor, may be provided.

Pyrolysis of ammonia is promoted in a low pressure environment. For this reason, it is conceivable to thermally decompose ammonia in a low-pressure environment and then boost the pressure with a booster in order to send the decomposed gas to the gas utilization target. The volume of gas after the decomposition reaction of ammonia is twice the volume of ammonia gas before the reaction. Therefore, the size of the booster that boosts the gas after the decomposition reaction is larger than the size of the booster that boosts the ammonia gas before the reaction. Further, the boosting power of the booster that boosts the gas after the decomposition reaction is larger than the boosting power of the booster that boosts the ammonia gas before the reaction. That is, this method increases equipment cost and running cost. On the other hand, in this embodiment, the ammonia before being supplied to the ammonia decomposition device is boosted to a pressure higher than the pressure in the combustor by the ammonia booster, and the bleed air before being supplied to the ammonia decomposition device is bleed. The air booster boosts the pressure to a level higher than the pressure inside the combustor. Therefore, in this embodiment, this gas can be guided into the combustor without boosting the pressure of the gas after decomposing ammonia. Moreover, in this embodiment, since the bleed air having a pressure higher than that of the atmosphere is boosted by the bleed air booster, the load on the bleed air booster is small. Therefore, in this aspect, the equipment cost and the running cost can be suppressed.

Further, in the ammonia decomposition equipment of any of the above embodiments, the ammonia decomposition apparatus uses the extracted air from the extracted air line as an oxidizing agent to burn a part of the ammonia from the ammonia supply line. Ammonia self-thermal decomposition device that self-decomposes the ammonia to generate a decomposition gas containing hydrogen, nitrogen, and residual ammonia, and removes the residual ammonia contained in the decomposition gas from the ammonia self-thermal decomposition device. It may also have an ammonia removing device for discharging the gas from which the residual ammonia has been removed from the decomposed gas as the treated gas.

In addition to the ammonia self-pyrolysis device, the ammonia decomposition device of this embodiment includes an ammonia removing device that removes residual ammonia contained in the decomposition gas from the ammonia self-pyrolysis device. Therefore, in this embodiment, the residual ammonia in the fuel supplied to the combustor can be reduced, so that the NOx concentration contained in the exhaust gas generated by the combustion of the fuel can be suppressed.

In the ammonia decomposition equipment of the embodiment having the ammonia self-pyrolysis device, the ammonia self-pyrolysis device may include an ammonia heater and an ammonia self-pyrolysis device. In this case, the ammonia heater is provided in the ammonia supply line, and heat exchanges the ammonia flowing through the ammonia supply line with the decomposition gas to heat the ammonia and cool the decomposition gas. It is a heat exchanger. Further, in this case, the ammonia self-pyrolyzer uses the extracted air from the extracted air line as an oxidant to burn a part of the ammonia after being heated by the ammonia heater, and self-produces the ammonia. It is thermally decomposed to generate the decomposed gas.

In this embodiment, the heat of the decomposition gas generated in the ammonia decomposition facility is used as the heat for heating the ammonia. Therefore, in this embodiment, the equipment cost and the running cost can be suppressed as compared with the case where the heat outside the ammonia decomposition equipment is used as the heat for heating the ammonia.

In the ammonia decomposition equipment of any of the above embodiments having the ammonia removing device, the ammonia removing device may have an ammonia absorber and an ammonia separator. In this case, the ammonia absorber brings the decomposition gas from the ammonia self-pyrolysis apparatus into contact with water to dissolve the residual ammonia in the decomposition gas in the water, while the treated decomposition gas. To discharge. The ammonia separator has a separation tower and a water heater. The separation tower brings the ammonia water, which is the water in which the residual ammonia is dissolved, into contact with water vapor, heats the ammonia water, and separates ammonia from the ammonia water. The water heater heats water in which ammonia is separated from the ammonia water to make steam, and then returns the steam to the separation tower.

In the ammonia decomposition facility of the above embodiment having the water heater, the water heater heats the water to be steamed by exchanging heat between the water in which ammonia is separated from the ammonia water and the decomposition gas. It may be a exchanger.

In this embodiment, in the water heater, the heat of the decomposition gas generated in the ammonia decomposition equipment is used as the heat for heating the water. Therefore, in this embodiment, the equipment cost and the running cost can be suppressed as compared with the case where the heat outside the ammonia decomposition equipment is used as the heat for heating the water in the water heater.

The gas turbine plant as one aspect of the invention for achieving the above object is
The ammonia decomposition equipment of any of the above aspects and the gas turbine are provided.

The method for decomposing ammonia as one aspect of the invention for achieving the above object is
In the ammonia decomposition device, part of the ammonia is burned using the extracted air, which is a part of the compressed air that is the air compressed by the compressor of the gas turbine, as an oxidizing agent, and the ammonia is self-thermally decomposed into hydrogen. An ammonia decomposition step of producing a processed gas containing nitrogen and a processed gas supply step of guiding the processed gas generated in the ammonia decomposition step to a combustor of the gas turbine as fuel are executed.

Here, in the ammonia decomposition method of the above embodiment, the ammonia before self-thermal decomposition in the ammonia decomposition step is pressurized to a pressure higher than the pressure in the combustor, and then the ammonia after the pressure is increased to the ammonia decomposition apparatus. The bleed air before being used as the oxidant in the ammonia supply step and the ammonia decomposition step is boosted to a pressure higher than the pressure in the combustor, and then the bleed air after the boost is boosted to the ammonia decomposition device. The bleed air supply step of supplying to the air may be performed.

Further, in the ammonia decomposition method of any of the above embodiments, in the ammonia decomposition step, a part of the ammonia is burned using the extracted air before being used as the oxidizing agent as the oxidizing agent, and the ammonia is produced. Ammonia self-thermal decomposition step of producing a decomposition gas containing hydrogen, nitrogen and residual ammonia, and the residual ammonia was removed from the decomposition gas, and the residual ammonia was removed from the decomposition gas. It may include an ammonia removing step of discharging the gas as the treated gas.

In the ammonia decomposition method of the embodiment in which the ammonia self-pyrolysis step is executed, the ammonia self-pyrolysis step may include an ammonia preheating step and an ammonia self-thermal decomposition execution step. In this case, in the ammonia preheating step, the ammonia and the decomposition gas are heat-exchanged to heat the ammonia while cooling the decomposition gas. Further, in the ammonia self-pyrolysis execution step, the extracted air before being used as the oxidizing agent is used as an oxidizing agent, and a part of the ammonia after being heated in the ammonia preheating step is burned to burn the ammonia. The decomposition gas is produced by self-pyrolysis.

In any of the above-described methods for decomposing ammonia in which the ammonia removing step is executed, the ammonia removing step may include an ammonia absorption step and an ammonia separation step. In this case, in the ammonia absorption step, the decomposition gas obtained in the execution of the ammonia self-thermal decomposition step is brought into contact with water to dissolve the residual ammonia in the decomposition gas in water, while the treatment. Discharge the finished gas. The ammonia separation step includes a separation execution step and a water heating step. In the separation execution step, ammonia water, which is water in which the residual ammonia is dissolved, is brought into contact with water vapor, and ammonia is evaporated and separated from the ammonia water. In the water heating step, the water in which ammonia is separated from the ammonia water is heated to obtain steam used in the separation execution step.

In the ammonia decomposition method of the embodiment in which the water heating step is executed, in the water heating step, the water in which ammonia is separated from the ammonia water and the decomposition gas are heat-exchanged, and the water is heated to steam. May be good.

In any of the above aspects of the ammonia decomposition method, the residual ammonia concentration in the treated gas may be set to a desired value. This desired value is a value at which the nitrogen oxide concentration in the exhaust gas conforms to the environmental regulation of the nitrogen oxide concentration at the installation point of this plant, or when a denitration device is installed in the exhaust gas path, nitrogen after denitration. The oxide concentration can be determined to be a value that complies with environmental regulations.

According to one aspect of the present invention, it is possible to reduce the equipment cost of a turbine plant that uses gas obtained by decomposing ammonia as fuel.

It is a system diagram of the gas turbine plant in one Embodiment which concerns on this invention. It is a system diagram of the ammonia decomposition equipment in one Embodiment which concerns on this invention. It is a flowchart which shows the ammonia decomposition procedure in the ammonia decomposition apparatus in 1st Embodiment which concerns on this invention. It is a graph which shows the relationship between various temperature and pressure in a thermal decomposition environment of ammonia, and residual ammonia concentration. It is a graph which shows the relationship between the residual ammonia concentration and the predicted value of NOx concentration in exhaust gas.

Hereinafter, an embodiment of the gas turbine plant and various modifications will be described with reference to the drawings.

"Embodiment"
An embodiment of a gas turbine plant will be described with reference to FIGS. 1 to 5.

As shown in FIG. 1, the gas turbine plant of the present embodiment includes a gas turbine facility 10, an exhaust heat recovery steam generator 20, a steam turbine facility 30, and an ammonia decomposition facility X.

The gas turbine equipment 10 includes a gas turbine 11, a fuel line 12 that guides fuel to the gas turbine 11, a flow meter 13 that detects the flow rate of fuel flowing through the fuel line 12, and a preheater that preheats the fuel flowing through the fuel line 12. A fuel control valve 15 for adjusting the flow rate of fuel supplied to the gas turbine 11 is provided.

The gas turbine 11 includes an air compressor 11a that compresses air to generate compressed air, a combustor 11b that burns fuel in compressed air to generate combustion gas, and a turbine 11c that is driven by the combustion gas. Have. The combustor 11b has a structure capable of stably combusting a gas fuel containing hydrogen as a main component. The air compressor 11a has a compressor rotor and a compressor casing that covers the compressor rotor. The turbine 11c includes a turbine rotor and a turbine casing that covers the turbine rotor. The compressor rotor and the turbine rotor are connected to each other to form the gas turbine rotor 11d. The fuel line 12 is connected to the combustor 11b. The fuel line 12 is provided with the flow meter 13, the preheater 14, and the fuel control valve 15 described above.

The exhaust heat recovery boiler 20 includes a boiler frame 21 through which the exhaust gas EG from the gas turbine 11 flows, a low-pressure steam generation system 22, a medium-pressure steam generation system 23, a reheat steam system 25, and a high-pressure steam generation system 26. , A medium pressure pump 24 and a high pressure pump 27. Here, the upstream side regarding the flow of the exhaust gas EG in the boiler frame 21 is simply the upstream side, and the opposite side is the downstream side. A stack 29 that exhausts the exhaust gas EG to the atmosphere is connected to the most downstream end of the boiler frame 21.

The low-pressure steam generator 22 includes an economizer 22a, an evaporator 22b, and a superheater 22c. The economizer 22a exchanges heat between water and the exhaust gas EG to heat the water into hot water. The evaporator 22b heats the water into steam by exchanging heat between a part of the hot water from the economizer 22a and the exhaust gas EG. The superheater 22c heats the water vapor by exchanging heat between the water vapor from the evaporator 22b and the exhaust gas EG. The economizer 22a, at least a part of the evaporator 22b, and the superheater 22c are all arranged in the boiler frame 21. The economizer 22a, at least a part of the evaporator 22b, and the superheater 22c are arranged in this order from the downstream side to the upstream side.

Although the medium-pressure steam generator system 23 and the high-pressure steam generator system 26 are not shown, they both have an economizer, an evaporator, and a superheater, similar to the low-pressure steam generator system 22. The medium-pressure pump 24 boosts a part of the hot water from the economizer 22a of the low-pressure steam generator 22 and then sends it to the economizer of the medium-pressure steam generator 23. The economizer 22a of the low-pressure steam generator 22 and the economizer of the high-pressure steam generator 26 are connected by a hot water line 49. The high-pressure pump 27 is provided in the hot water line 49. The high-pressure pump 27 boosts a part of the hot water from the economizer 22a of the low-pressure steam generator 22 and then sends it to the economizer of the high-pressure steam generator 26.

Of the superheaters of the steam generators 22, 23, and 26, the superheater of the high-pressure steam generator 26 is arranged in the boiler frame 21 on the upstream side of the other superheaters. The superheater of the medium-pressure steam generator system 23 is arranged in the boiler frame 21 on the downstream side of the superheater of the high-pressure steam generator system 26. The superheater 22c of the low-pressure steam generator 22 is arranged in the boiler frame 21 on the downstream side of the superheater of the medium-pressure steam generator 23.

The reheat steam system 25 has only a reheater that superheats steam with the exhaust gas EG. The reheated steam system 25 is arranged on the downstream side of the superheater of the high-pressure steam generating system 26 and on the upstream side of the superheater of the medium-pressure steam generating system 23.

The steam turbine equipment 30 includes a low-pressure steam turbine 31, a medium-pressure steam turbine 32, a high-pressure steam turbine 33, a condenser 35, and a condenser pump 36. The low pressure steam turbine 31 has a low pressure steam turbine rotor and a casing that covers the low pressure steam turbine rotor. The medium pressure steam turbine 32 has a medium pressure steam turbine rotor and a casing that covers the medium pressure steam turbine rotor. The high-pressure steam turbine 33 has a high-pressure steam turbine rotor and a casing that covers the high-pressure steam turbine rotor. The low pressure steam turbine rotor, the medium pressure steam turbine rotor, and the high pressure steam turbine rotor are connected to each other to form one steam turbine rotor 34. The gas turbine rotor 11d described above is connected to one end of the steam turbine rotor 34. A generator 39 is connected to the other end of the steam turbine rotor 34.

The superheater of the high-pressure steam generation system 26 and the steam inlet of the high-pressure steam turbine 33 are connected by a high-pressure steam line 44. The steam outlet of the high-pressure steam turbine 33 and the steam inlet of the reheat steam system 25 are connected by a high-pressure exhaust steam line 46. The steam inlet of the reheat steam system 25 is further connected to the superheater of the medium pressure steam generation system 23 by a medium pressure steam line 42. The steam outlet of the reheat steam system 25 and the steam inlet of the medium pressure steam turbine 32 are connected by a reheat steam line 43. The superheater 22c of the low-pressure steam generator 22 and the steam inlet of the low-pressure steam turbine 31 are connected by a low-pressure steam line 41. The steam inlet of the low pressure steam turbine 31 is further connected to the steam outlet of the medium pressure steam turbine 32 by a medium pressure exhaust steam line 45. The above-mentioned condenser 35 is connected to the steam outlet of the low-pressure steam turbine 31. The condenser 35 returns the steam exhausted from the low-pressure steam turbine 31 to the liquid phase water. The condenser 35 and the economizer 22a of the low-pressure steam generator 22 are connected by a water supply line 47. The above-mentioned condensate pump 36 is provided in the water supply line 47.

The ammonia decomposition equipment X includes an ammonia decomposition device 50, an ammonia supply line 81, an ammonia booster 80, a processed gas supply line 82, an bleed air line 85, an bleed air cooler 86, and an bleed air booster 87. A cooling medium line 88i, a cooling medium recovery line 88o, and a fuel buffer 89 are provided.

The ammonia supply line 81 connects the ammonia tank T in which liquid ammonia is stored and the ammonia decomposition device 50. The liquid ammonia stored in the ammonia tank T is, for example, produced from hydrogen as a raw material. This hydrogen is, for example, hydrogen obtained by electrolyzing water using electricity generated by renewable energy such as wind power or sunlight, or hydrogen obtained by steam reforming natural gas. is there. Hydrogen is not as easy to transport and store as liquefied natural gas. Therefore, the hydrogen obtained as described above is used to produce liquid ammonia that can be easily transported and stored, and the liquid ammonia is stored in the ammonia tank T. The ammonia booster 80 is provided in the ammonia supply line 81. The ammonia booster 80 is a pump. The ammonia booster 80 boosts the liquid ammonia flowing through the ammonia supply line 81.

The bleed air line 85 connects the compressed air passage 11e between the discharge port of the air compressor 11a of the gas turbine 11 to the compressed air inlet of the combustor 11b, and the ammonia decomposition device 50. Therefore, the bleed air BA, which is a part of the compressed air generated by the air compressor 11a, flows through the bleed air line 85. The rest of the compressed air generated by the air compressor 11a is sent to the combustor 11b via the compressed air passage 11e. The bleed air cooler 86 is provided in the bleed air line 85 and cools the bleed air BA flowing through the bleed air line 85. The bleed air booster 87 is provided at a position closer to the ammonia decomposition device 50 than the bleed air cooler 86 in the bleed air line 85. The bleed air booster 87 boosts the bleed air BA cooled by the bleed air cooler 86.

The bleed air cooler 86 is a heat exchanger that heats the cooling medium while cooling the bleed air BA by exchanging heat between the bleed air BA and the cooling medium. One end of the cooling medium line 88i is connected to the cooling medium inlet of the bleed air cooler 86. The other end of the cooling medium line 88i is connected to a position on the high pressure steam generation system 26 side of the high pressure pump 27 in the hot water line 49 of the exhaust heat recovery boiler 20. Therefore, a part of the hot water from the economizer 22a of the low-pressure steam generator 22 is supplied to the bleed air cooler 86 as a cooling medium. One end of the cooling medium recovery line 88o is connected to the cooling medium outlet of the bleed air cooler 86. The other end of the cooling medium recovery line 88o is connected to the economizer of the high-pressure steam generator system 26. Therefore, hot water, which is a cooling medium heated by heat exchange with the bleed air BA, flows into the economizer of the high-pressure steam generation system 26. Hot water from the economizer 22a of the low-pressure steam generator 22 also flows into the economizer of the high-pressure steam generator 26 via the hot water line 49.

The ammonia decomposition device 50 uses the extracted air BA from the extracted air line 85 as an oxidant to burn a part of the ammonia from the ammonia supply line 81, and the heat at this time self-pyrolyzes the ammonia to generate hydrogen. Produces a treated gas PG containing nitrogen.

One end of the treated gas supply line 82 is connected to the ammonia decomposition device 50. The treated gas PG generated by the ammonia decomposition apparatus 50 flows through the treated gas supply line 82. The fuel buffer 89 described above is provided at the other end of the processed gas supply line 82. A start-up fuel line 16 is further connected to the fuel buffer 89. The start-up fuel SF flows through the start-up fuel line 16. The start-up fuel SF is, for example, hydrogen, natural gas, or the like. The fuel line 12 described above is further connected to the fuel buffer 89. The fuel buffer 89 is a buffer for temporarily retaining the starting fuel SF from the starting fuel line 16 and the processed gas PG from the processed gas supply line 82. The fuel buffer 89 includes the start-up fuel line 16 and the treated gas supply line 82 in order to ensure the stability of the fuel supply to the combustor 11b when the fuel is switched from the start-up fuel SF to the treated gas PG. It is provided at the confluence of.

The ammonia decomposition device 50 includes an ammonia self-thermal decomposition device 51 and an ammonia removal device 61. The ammonia self-pyrolyzer 51 uses the extracted air BA boosted by the bleed air booster 87 as an oxidizing agent to burn a part of the ammonia boosted by the ammonia booster 80, and uses the heat at this time to self-produce ammonia. Pyrolysis is carried out to produce a decomposition gas DG containing hydrogen, nitrogen and residual ammonia. The ammonia removing device 61 removes residual ammonia contained in the decomposition gas DG from the ammonia self-thermal decomposition device 51. The treated gas PG described above is a gas from which residual ammonia has been removed from the decomposition gas DG.

As shown in FIG. 2, the ammonia self-pyrolysis apparatus 51 includes a first ammonia heater 52a, a second ammonia heater 52b, an ammonia self-pyrolysis device 53, and a decomposition gas line 54. The ammonia supply line 81 described above is connected to the ammonia self-pyrolyzer 53.

The first ammonia heater 52a is provided at a position on the ammonia self-thermal decomposition device 53 side of the ammonia booster 80 in the ammonia supply line 81. The first ammonia heater 52a is a heat exchanger that exchanges heat between the liquid ammonia boosted by the ammonia booster 80 and the decomposition gas DG. The first ammonia heater 52a heats the liquid ammonia by heat exchange between the liquid ammonia and the decomposition gas DG, and turns the liquid ammonia into vapor phase ammonia. The second ammonia heater 52b is provided at a position on the ammonia self-thermal decomposition device 53 side of the first ammonia heater 52a in the ammonia supply line 81. The second ammonia heater 52b further heats the ammonia in the gas phase by heat exchange between the ammonia in the gas phase and the decomposition gas DG from the first ammonia heater 52a.

The ammonia self-pyrolyzer 53 uses the extracted air BA from the extracted air line 85 as an oxidizing agent to burn a part of the ammonia in the gas phase from the ammonia supply line 81, and self-pyrolyzes the ammonia with the heat at this time. To generate a decomposition gas DG containing hydrogen, nitrogen and residual ammonia. The ammonia self-thermal decomposition device 53 is filled with a catalyst for promoting the oxidation (combustion) of ammonia and the thermal decomposition of ammonia. The catalyst has a catalyst component that activates an oxidation (combustion) reaction or a decomposition reaction, and a carrier that supports the catalyst component. Examples of the catalyst component that activates the oxidation (combustion) reaction include particles of a noble metal such as platinum, palladium, and rhodium. In addition, examples of the catalyst component that activates the decomposition reaction include particles of a noble metal such as Ru and metal particles containing a transition metal such as Ni, Co, and Fe. Examples of the carrier include metal oxides such as Al ₂ O ₃ , ZrO ₂ , Pr ₂ O ₃ , La ₂ O ₃ , and MgO. The catalyst is not limited to the catalysts exemplified above as long as it activates the oxidation (combustion) reaction and decomposition reaction of ammonia.

A decomposition gas line 54 that guides the decomposition gas DG generated in the ammonia self-thermal decomposition unit 53 to the ammonia removal device 61 is connected to the ammonia self-thermal decomposition unit 53. The decomposition gas line 54 has a first line 54a, a second line 54b, a third line 54c, and a fourth line 54d. One end of the first line 54a is connected to the decomposition gas outlet of the ammonia self-thermal decomposition device 53, and the other end of the first line 54a is connected to the heat medium inlet of the second ammonia heater 52b. One end of the second line 54b is connected to the heat medium outlet of the second ammonia heater 52b, and the other end of the second line 54b is connected to the heat medium inlet of the water heater 77 in the ammonia removing device 61 described later. ing. One end of the third line 54c is connected to the heat medium outlet of the water heater 77 in the ammonia removing device 61, and the other end of the third line 54c is connected to the heat medium inlet of the first ammonia heater 52a. .. One end of the fourth line 54d is connected to the heat medium outlet of the first ammonia heater 52a, and the other end of the fourth line 54d is connected to the ammonia removing device 61. Therefore, the decomposition gas DG generated in the ammonia self-thermal decomposition device 53 is the first line 54a, the second ammonia heater 52b, the second line 54b, the water heater 77 in the ammonia removing device 61, the third line 54c, and the first line. (1) It is guided to the ammonia removing device 61 via the ammonia heater 52a and the fourth line 54d. In the second ammonia heater 52b described above, the decomposition gas DG that exchanges heat with ammonia is the decomposition gas DG that has flowed into the second ammonia heater 52b from the ammonia self-thermal decomposition device 53 via the first line 54a. Further, in the first ammonia heater 52a described above, the decomposition gas DG that exchanges heat with ammonia flows into the first ammonia heater 52a from the water heater 77 in the ammonia removing device 61 via the third line 54c. Gas DG.

As shown in FIG. 2, the ammonia removing device 61 includes an ammonia absorber 62 and an ammonia separator 72.

The ammonia absorber 62 includes a decomposed gas cooler 63, an absorption tower 64, a water line 65, a water supply pump 66, and a water cooler 67. The other end of the fourth line 54d in the decomposition gas line 54 described above is connected to the absorption tower 64. The decomposition gas cooler 63 is provided on the fourth line 54d of the decomposition gas line 54. The decomposition gas cooler 63 further cools the decomposition gas DG cooled by heat exchange with ammonia in the second ammonia heater 52b and the first ammonia heater 52a. The absorption tower 64 has an absorption tower container 64v and a filling material 64p. The filling 64p is arranged in the intermediate basin in the vertical direction in the absorption tower container 64v. The fourth line 54d of the decomposition gas line 54 is connected below the intermediate region in the absorption tower container 64v. The water line 65 is connected above the intermediate region in the absorption tower container 64v. The water line 65 is provided with a water supply pump 66 that boosts the water flowing through the water line 65 and a water cooler 67 that cools the water flowing through the water line 65. One end of the treated gas supply line 82 described above is connected to the top of the absorption tower container 64v. Therefore, the processed gas supply line 82 connects the absorption tower 64 and the fuel buffer 89.

The decomposed gas DG cooled by the decomposition gas cooler 63 flows into the absorption tower container 64v from below the intermediate region of the absorption tower container 64v. Further, water cooled by the water cooler 67 is sprayed into the absorption tower container 64v from above the intermediate region of the absorption tower container 64v. The decomposition gas DG that has flowed into the absorption tower container 64v rises in the absorption tower container 64v. On the other hand, the water sprayed in the absorption tower container 64v descends in the absorption tower container 64v. The water comes into contact with the filling 64p in the process of descending in the absorption tower container 64v. The water in contact with the filling 64p forms a water film covering the surface of the filling 64p. The decomposition gas DG comes into contact with the water film covering the surface of the filling 64p in the process of ascending in the absorption tower container 64v. In this process, the residual ammonia contained in the decomposition gas DG dissolves in water. Ammonia water, which is water in which residual ammonia is dissolved, collects in the lower part of the absorption tower container 64v. The treated gas PG, which is the decomposed gas DG from which the residual ammonia has been removed, rises in the absorption tower container 64v and flows into the treated gas supply line 82.

The ammonia separator 72 includes an ammonia water line 73, an ammonia water heater 74, a separation tower 75, a water circulation line 76, a water heater 77, and a condenser 78. One end of the ammonia water line 73 is connected to the bottom of the absorption tower container 64v. The separation tower 75 has a separation tower container 75v and a perforated plate type shelf 75p. A plurality of stages constituting the shelf stage 75p are arranged side by side in the vertical direction in the intermediate basin in the vertical direction in the separation tower container 75v. The other end of the above-mentioned ammonia water line 73 is connected to an intermediate stage among a plurality of stages constituting the shelf stage 75p. One end of the water circulation line 76 is connected to the bottom of the separation tower container 75v, and the other end of the water circulation line 76 is connected above the bottom and below the intermediate region in the separation tower container 75v. The water heater 77 is provided on the water circulation line 76. The water heater 77 is a heat exchanger that exchanges heat between the water flowing through the water circulation line 76 and the decomposition gas DG flowing in from the second line 54b of the decomposition gas line 54. The water heater 77 exchanges heat between the water and the decomposition gas DG, and heats the water into steam while cooling the decomposition gas DG. This water vapor flows into the separation tower container 75v via the water circulation line 76. On the other hand, as described above, the decomposition gas DG flows from the water heater 77 into the first ammonia heater 52a via the third line 54c of the decomposition gas line 54.

Water vapor flows into the separation tower container 75v from below the intermediate region of the separation tower container 75v. Further, in the separation tower container 75v, the ammonia water from the ammonia water line 73 is sprayed from the middle stage in the shelf stage 75p. The water vapor that has flowed into the separation tower container 75v rises in the separation tower container 75v. Ammonia water sprayed on the middle stage of the shelf stage 75p gradually flows down to the lower stage while forming a liquid layer on each stage of the shelf stage 75p. The water vapor rises in gas-liquid contact with the ammonia water via a large number of holes provided in each stage of the shelf 75p, and heats the ammonia water. Ammonia, which evaporates more easily than water, is heated by water vapor, which is water in the gas phase, to move from the liquid phase to the gas phase, and water moves from the gas phase to the liquid phase. Ammonia in the gas phase rises in the separation tower 75. Also, liquid phase water, or more precisely water with a low ammonia concentration, collects in the lower part of the separation tower container 75v. A part of this water flows into the separation tower container 75v again as steam through the water circulation line 76 and the water heater 77.

The water line 65 of the ammonia absorber 62 is connected to the water circulation line 76. Therefore, a part of the water collected in the lower part of the separation tower container 75v returns to the inside of the separation tower container 75v again through the water circulation line 76, and the other part of the water collected in the lower part of the separation tower container 75v becomes. It flows into the absorption tower 64 via the water circulation line 76 and the water line 65.

The ammonia water heater 74 is provided in the ammonia water line 73. The ammonia water heater 74 is a heat exchanger that exchanges heat between the ammonia water flowing through the ammonia water line 73 and the water flowing through the water line 65. The ammonia water heater 74 heats the ammonia water by heat exchange between the ammonia water and the water. The heated ammonia water is sprayed into the separation tower container 75v as described above. On the other hand, the water cooled by heat exchange with the ammonia water is sprayed into the absorption tower container 64v via the water line 65, the water supply pump 66, and the water cooler 67.

As shown in FIG. 2, the ammonia decomposition facility X further includes an ammonia recovery line 83 and an ammonia compressor 84.

One end of the ammonia recovery line 83 is connected to the top of the separation tower container 75v, and the other end of the ammonia recovery line 83 is between the first ammonia heater 52a and the second ammonia heater 52b in the ammonia supply line 81. It is connected to the position. The ammonia compressor 84 boosts the ammonia in the gas phase flowing through the ammonia recovery line 83. The vapor-phase ammonia boosted by the ammonia compressor 84 merges with the vapor-phase ammonia flowing through the ammonia supply line 81, passes through the second ammonia heater 52b, and then flows into the ammonia self-thermal decomposition device 53. The condenser 78 is provided on the ammonia recovery line 83. The condenser 78 cools a gas containing ammonia in the gas phase flowing through the ammonia recovery line 83 to condense the water and ammonia in the gas. The water condensed by the condenser 78 returns to the space above the shelf 75p in the separation tower container 75v via the water recovery line 79. The number of shelves 75p is planned to be the number of stages required for this high-concentration ammonia water to become a trace amount of ammonia water having a desired concentration. The concentration of the ammonia water supplied from the ammonia water line 73 is lower than that of the high-concentration ammonia water discharged from the condenser 78. Therefore, the number of shelves required for separating the ammonia water supplied from the ammonia water line 73 is smaller than the planned number of shelves from the high-concentration ammonia water from the condenser 78. Therefore, the connection destination of the ammonia water supplied from the ammonia water line 73 is an intermediate stage among the plurality of stages constituting the shelf stage 75p.

Next, the operation and operation of the gas turbine plant described above will be described.

When the gas turbine 11 is started, the start-up fuel SF is supplied to the combustor 11b via the start-up fuel line 16 and the fuel line 12. As described above, the air compressor 11a of the gas turbine 11 compresses the air to generate compressed air. The combustor 11b burns the starting fuel SF in the compressed air to generate a combustion gas. This combustion gas is supplied to the turbine 11c to drive the turbine 11c. The exhaust gas EG, which is the combustion gas that drives the turbine 11c, flows into the boiler frame 21 of the exhaust heat recovery boiler 20.

In the steam generation systems 22, 23, and 26 of the exhaust heat recovery boiler 20, the exhaust gas EG flowing in the boiler frame 21 and water are exchanged for heat to turn the liquid phase water into steam. A part of the hot water from the economizer 22a of the low-pressure steam generator 22 is boosted by the high-pressure pump 27 and then sent to the high-pressure steam generator 26. The temperature of this hot water is, for example, 150 ° C. The hot water sent to the high-pressure steam generation system 26 becomes high-pressure steam HS by heat exchange with the exhaust gas EG. This high-pressure steam HS is, for example, superheated steam at about 620 ° C. This high-pressure steam HS is supplied to the high-pressure steam turbine 33 via the high-pressure steam line 44. The high-pressure steam turbine 33 is driven by the high-pressure steam HS.

A part of the hot water from the economizer 22a of the low-pressure steam generator 22 is boosted by the medium-pressure pump 24 and then sent to the medium-pressure steam generator 23. The hot water sent to the medium-pressure steam generation system 23 becomes medium-pressure steam IS by heat exchange with the exhaust gas EG. This medium pressure steam IS is, for example, superheated steam at 300 ° C. The medium pressure steam IS flows into the reheat steam system 25 via the medium pressure steam line 42. Further, the steam exhausted from the high-pressure steam turbine 33 flows into the reheated steam system 25 via the high-pressure exhaust steam line 46. That is, the medium-pressure steam IS from the medium-pressure steam generation system 23 and the steam exhausted from the high-pressure steam turbine 33 flow into the reheat steam system 25. In the reheated steam system 25, the steam flowing into the reheated steam system 25 is heated by heat exchange with the exhaust gas EG to form the reheated steam RS. The reheated steam RS is supplied to the medium pressure steam turbine 32 via the reheated steam line 43. The medium-pressure steam turbine 32 is driven by the reheated steam RS supplied to the medium-pressure steam turbine 32.

A part of the hot water from the economizer 22a of the low-pressure steam generator 22 is heated by the exhaust gas EG in the evaporator 22b of the low-pressure steam generator 22 to become steam. This steam becomes the low-pressure steam LS superheated by the exhaust gas EG in the superheater 22c of the low-pressure steam generation system 22. This low-pressure steam LS is, for example, superheated steam at 250 ° C. This low-pressure steam LS is supplied to the low-pressure steam turbine 31 via the low-pressure steam line 41. Further, the steam exhausted from the medium pressure steam turbine 32 is supplied to the low pressure steam turbine 31 via the medium pressure exhaust steam line 45. That is, the low-pressure steam LS from the low-pressure steam generation system 22 and the steam exhausted from the medium-pressure steam turbine 32 are supplied to the low-pressure steam turbine 31. The low-pressure steam turbine 31 is driven by the steam supplied to the low-pressure steam turbine 31.

The steam exhausted from the low-pressure steam turbine 31 is returned to water by the condenser 35. The water in the condenser 35 is sent to the economizer 22a of the low-pressure steam generator 22 via the water supply line 47.

When the gas turbine 11 is in steady operation, for example, the liquid ammonia in the ammonia tank T and the extracted air BA from the gas turbine 11 are supplied to the ammonia self-thermal decomposition device 51. Hereinafter, the procedure for ammonia decomposition by the ammonia decomposition equipment X will be described with reference to the flowchart shown in FIG.

Liquid ammonia is stored in the ammonia tank T in a state of being cooled to a temperature of −33.4 ° C. or lower, which is the boiling point, and in a state of substantially atmospheric pressure. The liquid ammonia in the ammonia tank T is boosted to, for example, about 5.2 MPa (absolute pressure) by the ammonia booster 80, and then supplied to the ammonia decomposition apparatus 50 (S1: ammonia supply step). The pressure after pressurization of ammonia is determined in consideration of the pressure loss in the piping and various devices in the path until the liquid ammonia becomes the treated gas PG and the treated gas PG flows into the combustor 11b. This is the pressure at which the processed gas PG can be supplied into the combustor 11b into which the compressed air is flowing without boosting up the processed gas PG. Therefore, this pressure (about 5.2 MPa) is higher than the pressure in the combustor 11b. The pressure of the compressed air supplied to the combustor 11b is, for example, about 2.5 MPa, and the temperature of the compressed air is, for example, about 500 ° C.

In parallel with the above ammonia supply step (S1), the bleed air supply step (S2) is executed. In this bleed air supply step (S2), a part of the compressed air generated by the air compressor 11a of the gas turbine 11 is used as the bleed air BA, and the ammonia self-thermal decomposition of the ammonia decomposition apparatus 50 is performed through the bleed air line 85. It is supplied to the vessel 53. The bleed air BA from the air compressor 11a is, for example, 500 ° C. The bleed air BA flows into the bleed air cooler 86 via the bleed air line 85. In addition to the bleed air BA, hot water from the economizer 22a of the low-pressure steam generator 22 in the exhaust heat recovery boiler flows into the bleed air cooler 86 via the cooling medium line 88i. The temperature of this hot water is about 150 ° C. In the bleed air cooler 86, the bleed air BA and the hot water as a cooling medium exchange heat, and the bleed air BA is cooled to, for example, about 160 ° C. After that, the bleed air BA is cooled to, for example, about 35 ° C. by a cooler (not shown). The bleed air BA cooled to about 35 ° C. is boosted to, for example, about 5.2 MPa by the bleed air booster 87, and then supplied to the ammonia self-thermal decomposer 53 of the ammonia decomposition apparatus 50. In this way, the bleed air BA is cooled from about 500 ° C. to about 35 ° C. by the bleed air cooler 86 and a cooler (not shown), and then flows into the bleed air booster 87. Therefore, the volume of the bleed air BA flowing into the bleed air booster 87 is reduced, and the driving force required for the bleed air booster 87 can be reduced. The pressure after the pressure of the extracted air BA is a pressure determined in consideration of the pressure loss in the piping and various devices in the path until the treated gas PG containing a part of this gas flows into the combustor 11b. The pressure is such that the processed gas PG can be supplied into the combustor 11b into which the compressed air is flowing without boosting up the processed gas PG. Therefore, this pressure (about 5.2 MPa) is higher than the pressure in the combustor 11b (for example, about 2.5 MPa).

Further, in the bleed air cooler 86, hot water at about 150 ° C. is heated to, for example, about 330 ° C. by heat exchange with the bleed air BA. The hot water heated by the bleed air cooler 86 flows into the economizer of the high-pressure steam generation system 26 in the exhaust heat recovery boiler 20 via the cooling medium recovery line 88o. The economizer of the high-pressure steam generator 26 includes hot water of, for example, about 330 ° C. from the bleed air cooler 86, and hot water of, for example, about 150 ° C. from the economizer 22a of the low-pressure steam generator 22. Inflow. These hot waters are heated by the evaporator of the high-pressure steam generation system 26 to become steam, and then further superheated by the superheater of the high-pressure steam generation system 26 to become high-pressure steam HS. As described above, in addition to the hot water from the economizer 22a of the low-pressure steam generator 22, hot water having a temperature higher than that of the hot water also flows into the economizer of the high-pressure steam generator system 26. Therefore, the hot water can be heated by the exhaust gas in the high-pressure steam generation system 26, and the amount of heat for converting the hot water into the high-pressure steam HS can be suppressed. That is, the amount of heat of the exhaust gas consumed by the high-pressure steam generation system 26 can be reduced. Therefore, the heat of the exhaust gas EG can be effectively used downstream of the high-pressure steam generation system 26 in the exhaust heat recovery boiler 20.

In the ammonia decomposition apparatus 50, the extracted air BA from the extracted air line 85 is used as an oxidizing agent to burn a part of the ammonia from the ammonia supply line, and this heat self-pyrolyzes the ammonia to produce hydrogen and nitrogen. Produces a treated gas PG containing (S3: ammonia decomposition step).

In the ammonia decomposition step (S3), the ammonia self-thermal decomposition step (S4) and the ammonia removal step (S7) are executed. In the ammonia self-pyrolysis step (S4), a part of the ammonia from the ammonia supply line 81 is burned using the extracted air BA from the bleed air line 85 as an oxidizing agent, and the ammonia is self-pyrolyzed by this heat. It produces a decomposition gas DG containing hydrogen, nitrogen and residual ammonia. In this ammonia self-pyrolysis step (S4), the ammonia preheating step (S5) and the ammonia self-thermal decomposition execution step (S6) are executed.

In the ammonia preheating step (S3), the first ammonia heater 52a and the second ammonia heater 52b exchange heat between the ammonia and the decomposition gas DG, and while the ammonia is heated, the decomposition gas DG is cooled. The liquid ammonia boosted to about 5.2 MPs by the ammonia booster 80 flows into the first ammonia heater 52a of the ammonia self-thermal decomposition device 51. In the first ammonia heater 52a, the liquid ammonia and the decomposition gas DG are heat-exchanged, and the liquid ammonia is heated to about 170 ° C. Liquid ammonia evaporates to gaseous ammonia at 90 ° C. or higher in a pressure environment boosted by the ammonia booster 80. Therefore, gaseous ammonia at about 170 ° C. flows out from the first ammonia heater 52a. The gaseous ammonia from the first ammonia heater 52a flows into the second ammonia heater 52b. In the second ammonia heater 52b, the gaseous ammonia and the decomposed gas DG are heat-exchanged, and the gaseous ammonia is heated to about 400 ° C. This gaseous ammonia flows into the ammonia self-pyrolyzer 53.

The ammonia self-thermal decomposition execution step (S6) is executed in the ammonia self-thermal decomposition device 53. As described above, about 5.2 MPa of gaseous ammonia and about 5.2 MPa of bleed air BA flow into the ammonia self-pyrolyzer 53. In the ammonia self-pyrolyzer 53, as shown in the following formulas (1) and (2), first, a part of gaseous ammonia or the like undergoes an oxidation (combustion) reaction due to the action of the catalyst, and the heat of reaction is generated. discharge. Some of the remaining gaseous ammonia is heated to about 600 ° C from this heat of reaction and pyrolyzed as shown in formula (3) into hydrogen at about 600 ° C and nitrogen at about 600 ° C. Will be done. These hydrogen and nitrogen flow out from the ammonia self-thermal cracker 53 together with the gaseous ammonia (residual ammonia) that has not been thermally decomposed as a decomposed gas DG at about 600 ° C.
NH ₃ + 3/4O ₂ → 1/2N ₂ + 3 / 2H ₂ O + 317kJ / mol (1)
H ₂ + 1 / 2O ₂ → H ₂ O + 242kJ / mol (2)
_{NH 3 → 1 / 2N 2 +} 3 / 2H 2 -46kJ / mol (3)

As shown in the formula (3), gaseous ammonia is a reaction in which the number of moles after the reaction increases, so that the lower the pressure, the more promoted. In other words, this pyrolysis reaction is suppressed at high pressures. Further, since this pyrolysis reaction is an endothermic reaction, it is promoted at a higher temperature. The calorific value of NH _{3 on} the left side of the equation (3) is 317 kJ, and the calorific value of 3 / 2H _{2 on} the right side of the equation (3) is 363 kJ. Therefore, the heat generation amount of the fuel increases by 46 kJ due to the thermal decomposition reaction of the formula (3). However, the heat of reaction of 46 kJ per 1 mol of ammonia is required to cause this reaction, and the heat of reaction is supplemented by the heat of reaction generated by the oxidation reactions represented by the formulas (1) and (2). Therefore, in the self-pyrolysis reaction of ammonia, the thermal efficiency of the entire system basically does not change.

Here, the residual ammonia concentration remaining after the thermal decomposition reaction of gaseous ammonia under various conditions will be described with reference to the graph shown in FIG. In this graph, the horizontal axis is the temperature of the pyrolysis reaction environment (Temperature [deg-C]), and the vertical axis is the residual ammonia concentration (Concentration of Ammonia [%]). This graph is the result of trial calculation of the concentration corresponding to each temperature and each pressure by changing the temperature and pressure of the pyrolysis reaction environment and using the equilibrium coefficient of the pyrolysis reaction. The temperature of the pyrolysis reaction environment in the present embodiment is 600 ° C., and the pressure of this pyrolysis reaction environment is 5.2 MPa. Therefore, in the present embodiment, the residual ammonia concentration after the thermal decomposition reaction is about 4%. However, the graph shown in FIG. 4 is a graph showing the residual ammonia concentration remaining after the thermal decomposition reaction of ammonia when only ammonia is present as the raw material gas. On the other hand, in the present embodiment, in order to oxidize a part of ammonia, the extracted air BA is flowed into the ammonia self-thermal decomposition device 53, and nitrogen is produced by the oxidation reactions in the formulas (1) and (2). The gas composition at the outlet of the ammonia self-thermal decomposition device 53, that is, the gas composition of the decomposition gas DG flowing out from the ammonia self-thermal decomposition device 53 is about 48 mol% of hydrogen and about 39 mol% of nitrogen. , Water is about 10 mol% and residual ammonia is about 3 mol%. This completes the ammonia self-pyrolysis step (S3).

As described above, the decomposition gas DG at about 600 ° C. flowing out from the ammonia self-thermal decomposition device 53 flows into the second ammonia heater 52b via the first line 54a of the decomposition gas line 54, and here. It is cooled to about 350 ° C by heat exchange with gaseous ammonia at about 170 ° C. The decomposed gas DG flows into the water heater 77 via the second line 54b of the decomposed gas line 54, where it is further cooled to about 200 ° C. by heat exchange with water. The decomposition gas DG flows into the first ammonia heater 52a via the third line 54c of the decomposition gas line 54, where it is cooled to 50 ° C. by heat exchange with liquid ammonia.

When the ammonia self-pyrolysis step (S4) is completed, the ammonia removal step (S7) for removing residual ammonia from the decomposition gas DG obtained in the ammonia self-pyrolysis step (S4) is executed. In the ammonia removal step (S7), the ammonia absorption step (S8) and the ammonia separation step (S12) are executed.

In the ammonia absorption step (S8), first, the decomposition gas DG at about 50 ° C. flowing through the fourth line 54d of the decomposition gas line 54 is cooled by the decomposition gas cooler 63 of the ammonia absorber 62 to reach about 30 ° C. (S7: Decomposition gas DG cooling step). This decomposed gas DG flows into the absorption tower 64 of the ammonia absorber 62. Water at about 30 ° C. cooled by the water cooler 67 is sprayed into the absorption tower 64. In the absorption tower 64, as described above, the decomposition gas DG comes into contact with water, and the residual ammonia in the decomposition gas DG dissolves in water. Ammonia water, which is water in which residual ammonia is dissolved, collects in the lower part of the absorption tower container 64v (S10: ammonia absorption execution step). The ammonia concentration in this ammonia water is about 7 mol%. The concentration of ammonia in the gas phase dissolved in water is determined by the vapor-liquid equilibrium constant. The concentration of ammonia in this gas phase dissolved in water is higher at low temperatures. Therefore, the temperature of the decomposition gas DG flowing into the absorption tower 64 and the temperature of the water are set to about 30 ° C.

This completes the ammonia absorption step (S8).

The treated gas PG, which is the decomposed gas DG from which the residual ammonia has been removed, rises in the absorption tower container 64v and flows into the treated gas supply line 82. In the present embodiment, the mass flow rate of the water sprayed into the absorption tower 64 is set to about 1/3 of the mass flow rate of the decomposition gas DG flowing into the absorption tower 64, so that the residue contained in the treated gas PG The concentration of ammonia is about 0.02 mol% or less. Therefore, the gas composition of the treated gas PG in the present embodiment is about 55 mol% of hydrogen, about 45 mol% of nitrogen, and about 0.02 mol% or less of residual ammonia.

At the time of starting the gas turbine 11, the temperature of the ammonia self-pyrolyzer 53 and the fluid inside is low, and the condition is such that the decomposition reaction of ammonia is unlikely to occur, and most of the composition of the decomposition gas DG generated from the ammonia self-pyrolyzer 53. Is a residual ammonia component. Since the residual ammonia component is removed by the absorption tower 64, the flow rate of the treated gas PG supplied from the treated gas supply line 82 to the gas turbine 11 becomes smaller than the planned value. When a predetermined amount of the first heat medium M1 is supplied from the exhaust heat recovery boiler 20 to the ammonia self-pyrolyzer 53 after a lapse of time after the start of the gas turbine 11, the ammonia self-pyrolyzer 53 and the inside The temperature of the fluid reaches the planned value, and the decomposition reaction of ammonia is promoted. As a result, most of the composition of the decomposed gas DG becomes hydrogen and nitrogen, and a sufficient flow rate of the treated gas PG is produced from the absorption tower 64. Along with this process, the fuel supplied to the combustor 11b is gradually switched from the starting fuel SF to the processed gas PG. That is, when the processed gas PG is sufficiently generated, the supply of the fuel SF at startup to the combustor 11b is stopped, and the processed gas PG passes through the processed gas supply line 82 and the fuel line 12. It will be supplied to the combustor 11b (S11: processed gas supply process). The processed gas PG supplied to the combustor 11b burns in the combustor 11b. The temperature of the combustion gas produced as a result of this combustion is in the 1650 ° C. class. This combustion gas flows into the turbine 11c to drive the turbine 11c.

The exhaust gas EG exhausted from the turbine 11c flows into the exhaust heat recovery boiler 20. In the low-pressure steam generation system 22 of the exhaust heat recovery boiler 20, water is heated by the exhaust gas EG to generate low-pressure steam LS, as described above. This low-pressure steam LS is superheated steam at about 250 ° C. In the medium-pressure steam generation system 23 of the exhaust heat recovery boiler 20, water is heated by the exhaust gas EG to generate the medium-pressure steam IS, as described above. This medium pressure steam IS is superheated steam at about 300 ° C. In the high-pressure steam generation system 26 of the exhaust heat recovery boiler 20, water is heated by the exhaust gas EG to generate high-pressure steam HS as described above. This high-pressure steam HS is superheated steam at about 620 ° C.

Here, the relationship between the residual ammonia concentration contained in the fuel and the NOx concentration in the exhaust gas EG exhausted from the gas turbine 11 will be described with reference to the graph shown in FIG. In this graph, the horizontal axis is the residual ammonia concentration (Concentration of Ammonia [%]), and the vertical axis is the predicted value of NOx concentration in the exhaust gas EG (NOx Prediction [ppm @ 15% O2]). The predicted value of the NOx concentration is a value calculated by the inventor by modeling a one-dimensional laminar flow premixed flame using the PREMIX code of CHEMKIN. CHEMKIN is a calculation program. This CHEMKIN is explained in detail in the following materials.
Source: RJ Kee, FM Rupley, and JA Miller, Chemkin-II: A Fortran Chemical Kinetics Package for the Analysis of Gas-Phase Chemical Kinetics, Sandia Report, SAND89-8009B (1995)

In the present embodiment, since the residual ammonia concentration in the fuel is 0.02 mol% or less, the NOx concentration at the gas turbine 11 outlet can be predicted to be about 60 ppm or less from the graph shown in FIG. Therefore, in the gas turbine plant of the present embodiment, by installing a denitration device inside or outside the exhaust heat recovery boiler 20, the NOx concentration at the outlet of the stack 29 can be further suppressed to a desired concentration. It will be possible to comply with nitrogen oxide concentration regulations in many regions around the world.

When the ammonia absorption step (S8) is completed, the above-mentioned ammonia separation step (S12) for separating ammonia from the ammonia water produced in the ammonia absorption step (S8) is executed.

In the ammonia separation step (S12), first, the ammonia water at about 30 ° C. accumulated in the lower part of the absorption tower container 64v flows into the ammonia water heater 74. In this ammonia water heater 74, ammonia water at about 30 ° C. is heated to about 170 ° C. by heat exchange with water at about 190 ° C. (S13: Ammonia water heating step).

Ammonia water heated to about 170 ° C. flows into the separation tower 75. The separation tower 75 is a device provided for separating and distilling ammonia from aqueous ammonia using steam. Therefore, in order to lower the saturation temperature of water, the operating pressure in the separation tower container 75v is set to about 1.4 MPa. The operating pressure in the absorption tower container 64v is about 5.2 MPa as described above. Using the pressure difference between the pressure in the absorption tower container 64v and the pressure in the separation tower container 75v as a driving force, the ammonia water in the absorption tower container 64v flows into the separation tower container 75v via the ammonia water line 73. Further, water vapor at about 250 ° C. flows into the separation tower container 75v from the lower part of the separation tower container 75v. As described above, since the mass flow rate of the water sprayed into the absorption tower 64 is about 1/3 of the mass flow rate of the decomposition gas DG flowing into the absorption tower 64, the ammonia water flowing into the separation tower 75 The mass flow rate is also about 1/3 of the mass flow rate of the decomposed gas DG flowing into the absorption tower 64. The mass flow rate of water vapor required for distilling and separating ammonia from this mass flow rate of ammonia water is about 30% of the mass flow rate of ammonia water.

Ammonia water is heated by steam in the separation tower container 75v as described above, and ammonia in the ammonia water shifts from the liquid phase to the gas phase and rises in the separation tower container 75v (S14: Ammonia separation execution). Process). On the other hand, the water vapor moves to the liquid phase water and collects in the lower part of the separation tower container 75v. The temperature of this water is about 190 ° C. The ammonia concentration in this water is 0.05 mol%. A part of this water flows into the water heater 77 via the water circulation line 76. In the water heater 77, as described above, this water is heat-exchanged with the decomposition gas DG at about 350 ° C. that has flowed in from the second line 54b of the decomposition gas line 54. This water is heated to about 250 ° C. by heat exchange with the decomposition gas DG at about 350 ° C. to become steam (S15: water heating step). This water vapor is sent to the separation tower 75 via the water circulation line 76.

The other part of the water at about 190 ° C. collected in the lower part of the separation tower container 75v flows into the ammonia water heater 74 via the water line 65. In the ammonia water heater 74, as described above, the water at about 190 ° C. and the ammonia water at about 30 ° C. flowing through the ammonia water line 73 are heat-exchanged. By this heat exchange, the water is cooled to about 50 ° C., while the aqueous ammonia is heated to 170 ° C. as described above. This completes the ammonia decomposition step (S12). The water at about 50 ° C. cooled by the ammonia water heater 74 is boosted by the water supply pump 66, then flows into the water cooler 67, and is cooled by the water cooler 67 to reach about 30 ° C. .. As described above, the water at 30 ° C. is sprayed into the absorption tower 64.

The gas containing ammonia in the gas phase in the separation tower container 75v flows into the condenser 78 via the ammonia recovery line 83 connected to the top of the separation tower container 75v. In the condenser 78, this gas is cooled, and the water and ammonia contained in this gas are condensed into high-concentration ammonia water. This high-concentration ammonia water returns to the space above the shelf 75p in the separation tower container 75v via the water recovery line 79. This high-concentration ammonia water flows down each stage of the shelf stage 75p and comes into gas-liquid contact with the water vapor supplied from the lower stage, and ammonia is preferentially evaporated. As a result, the ammonia concentration in the water gradually decreases, and when it passes through the lowermost shelf, it becomes hot water having an ammonia concentration of 0.05 mol% or less. On the other hand, the gas from which water and the like have been removed by the condenser 78, that is, the gas having a high ammonia concentration in the gas phase, is boosted by the ammonia compressor 84 provided in the ammonia recovery line 83, and then the ammonia supply line 81 and It flows into the ammonia self-thermal decomposition device 53 via the second ammonia heater 52b (S16: ammonia recovery step). As described above, in the present embodiment, the residual ammonia removed by the ammonia removing device 61 returns to the ammonia supply line 81, so that the amount of waste in ammonia as a raw material can be minimized.

This completes a series of processes for ammonia decomposition by the ammonia decomposition facility X.

When the exhaust gas EG from the gas turbine 11 or the heat medium heated by the heat of the exhaust gas EG is used as the heat required for the thermal decomposition of ammonia, the exhaust gas EG or the heat medium is guided to the ammonia decomposer. It is necessary to newly design and manufacture equipment and an exhaust heat recovery boiler that separately generates this heat medium. On the other hand, in the present embodiment, the heat required for the thermal decomposition of ammonia is obtained by burning a part of ammonia. That is, in this embodiment, ammonia is self-pyrolyzed. Therefore, in the present embodiment, the equipment for guiding the exhaust gas EG and the heat medium to the ammonia decomposer, the exhaust heat recovery boiler for separately generating the heat medium, and the like are not required, and the equipment cost of the gas turbine plant can be suppressed. it can. Further, in the present embodiment, even when the remodeling work of adding the ammonia decomposition equipment X to the existing gas turbine combined cycle plant is performed, the exhaust heat recovery boiler 20 included in this plant can be used with almost no remodeling, so that the remodeling is performed. The cost can be suppressed.

In the present embodiment, the treated gas PG containing hydrogen obtained by decomposing ammonia is used as the main fuel for the combustor 11b. Therefore, carbon dioxide emissions can be reduced as compared with a plant that uses only natural gas as fuel for the combustor 11b.

The ammonia decomposition device 50 of the present embodiment is obtained from the ammonia self-pyrolysis device 51 in addition to the ammonia self-pyrolysis device 51 that self-pyrolyzes ammonia to generate a decomposition gas DG containing hydrogen, nitrogen and residual ammonia. The ammonia removing device 61 for removing the residual ammonia contained in the decomposition gas DG is provided. Therefore, in the present embodiment, the residual ammonia in the fuel supplied to the combustor 11b can be reduced, so that the NOx concentration contained in the exhaust gas EG generated by the combustion of the fuel can be suppressed.

As an oxidizing agent for self-pyrolyzing ammonia, a method using oxygen produced in an oxygen production facility can be considered. On the other hand, in the present embodiment, bleed air BA, which is a part of compressed air generated by the air compressor 11a of the gas turbine 11, is used as an oxidant for self-pyrolyzing ammonia. Therefore, in the present embodiment, the oxygen production equipment becomes unnecessary, and from this viewpoint as well, the equipment cost of the gas turbine plant can be suppressed.

Further, as an oxidant for self-pyrolyzing ammonia, bleed air BA, which is a part of compressed air generated by the air compressor 11a of the gas turbine 11, has the following merits. This merit will be described with reference to Tables 1 and 2. Note that Table 1 shows the case where the extracted air BA, which is a part of the compressed air generated by the air compressor 11a of the gas turbine 11, is used as the oxidizing agent for self-pyrolyzing ammonia as in the present embodiment. The gas mass flow rate, gas composition, gas calorific value, etc. in each treatment process of (self-pyrolysis method) are shown. In addition, Table 2 shows the gas mass flow rate, gas composition, gas calorific value, etc. in each treatment process when ammonia is thermally decomposed by heat from the outside (external heating method).

As shown in Table 1, the bleed air BA (C) extracted from the air compressor 11a of the gas turbine 11 contains about 21 vol% oxygen and about 79 vol% nitrogen. Here, of the compressed air generated by the air compressor 11a, 8.9% of the compressed air in terms of mass flow rate is used as the bleed air BA. When this bleed air BA is used as an oxidizing agent for ammonia, nitrogen and water vapor are generated by the oxidation reaction as described above using the formulas (1) and (2). Therefore, the composition of the decomposition gas DG (D) at the outlet of the ammonia self-pyrolyzer 53 is about 48 mol% of hydrogen, about 39 mol% of nitrogen, about 10 mol% of water, and about 3 mol% of residual ammonia. The calorific value is 124 kJ / mol. In the ammonia absorption tower 64, most of the moisture and residual ammonia are removed from the decomposed gas DG to become the treated gas PG (F). The unit calorific value of the treated gas PG is slightly increased from the unit calorific value of the decomposed gas DG to 133 kJ / mol.

As shown in Table 2, when ammonia is thermally decomposed by heat from the outside, the composition of the decomposition gas DG (D) at the outlet of the ammonia self-thermal decomposition device 53 is about 72 mol% for hydrogen and about 24 mol% for nitrogen. Residual ammonia is about 4 mol%, and its unit calorific value is 186 kJ / mol. In the ammonia absorption tower 64, most of the moisture and residual ammonia are removed from the decomposed gas DG to become the treated gas PG (F). The unit calorific value of the treated gas PG increases from the unit calorific value of the decomposed gas DG to 181 kJ / mol.

Therefore, the unit calorific value of the treated gas PG (F) by the self-pyrolysis method is about 0.73 times the unit calorific value of the treated gas PG (F) by the external heating method.

As described above, in the self-pyrolysis method, the volumetric flow rate of the fuel charged into the gas turbine 11 increases. When the volumetric flow rate of the fuel charged into the gas turbine 11 increases, the volumetric flow rate of the working fluid flowing into the gas path of the turbine 11c increases, and the pressure loss of the gas path on the turbine 11c side increases. Therefore, the pressure ratio of the turbine 11c becomes high, and the risk of an abnormal event such as a surge occurring in the air compressor 11a of the gas turbine 11 increases. In order to avoid such an abnormal event such as a surge in the air compressor 11a, it is necessary to lower the temperature of the combustion gas in the combustor 11b. However, lowering the combustion gas temperature leads to a decrease in thermal performance of the gas turbine 11 and the gas turbine combined cycle.

By the way, in the case of the external heating method, as shown in Table 2, the amount of increase in the working fluid flowing into the turbine 11c is 6.8% (based on the intake mass flow rate). On the other hand, in the present embodiment, as shown in Table 1, the bleed air BA, which is a part of the compressed air generated by the air compressor 11a of the gas turbine 11, is used as an oxidizing agent to flow into the turbine 11c. The net increase in fluid is 5.9% (based on intake mass flow rate). Further, in the self-pyrolysis method, when air other than the compressed air of the gas turbine 11 is used as an oxidant, it is obvious that the amount of increase in the working fluid flowing into the turbine 11c is larger than that of the present embodiment. Therefore, in the present embodiment, the amount of increase in the working fluid flowing into the turbine 11c is smaller than that in the external heating method or the self-pyrolysis method in which the compressed air of the gas turbine 11 is not used. Therefore, in the present embodiment, the risk of an abnormal event such as a surge in the air compressor 11a of the gas turbine 11 is reduced as compared with the external heating method or the self-pyrolysis method that does not use the compressed air of the gas turbine 11. As a result, in the present embodiment, the original combustion gas temperature of the gas turbine 11 can be maintained, and the thermal performance of the gas turbine 11 and the gas turbine combined cycle can be maintained. That is, in the present embodiment, the gas flow rate flowing through the air compressor 11a of the gas turbine 11 and the gas flow rate flowing through the turbine 11c of the gas turbine 11 are higher than those of the external heating method and the self-thermal decomposition method that does not use the compressed air of the gas turbine 11. Matching with is improved and thermal performance is improved.

In the present embodiment, the net increase in the working fluid flowing into the turbine 11c is 5.9% (based on the intake mass flow rate). Therefore, as shown in Table 3, a general natural gas is used for the combustor 11b. It is necessary to input fuel corresponding to 108% of the calorific value in the case of. On the other hand, in the ammonia decomposition apparatus 50, the ammonia decomposition gas once heated to a high temperature of about 600 ° C. is cooled to about 30 ° C. for the operation of the absorption tower 64, and is evaporated in the water heater 77 of the ammonia separator 72. There is heat loss that condenses the water vapor inside the separation tower 75, and it is necessary to input ammonia fuel equivalent to 115% of the calorific value of general natural gas when converted to the calorific value of ammonia before decomposition. Become. Since the power generation end output considering the power required for the operation of the ammonia decomposition facility X is 110%, the power generation efficiency of the plant in this embodiment is about 96% of the power generation efficiency of the natural gas-fired gas turbine combined cycle plant. become. Since the power generation end efficiency of the gas turbine combined cycle plant in the case of natural gas burning of 1650 ° C. is 63% (LHV standard) or more, the power generation end efficiency of the plant in the present embodiment is 60% (LHV standard) or more. Is possible. In this way, by using ammonia, which is one of the energy carriers of hydrogen, it is possible to provide a plant with high efficiency and significantly reduced carbon dioxide emissions.

As mentioned above, the thermal decomposition of ammonia is promoted in a low pressure environment. Therefore, a method of thermally decomposing ammonia in a low-pressure environment and then boosting the pressure with a booster to send the decomposed gas to the combustor 11b can be considered. The decomposition reaction of ammonia is a reaction in which the number of moles after the reaction is twice the number of moles before the reaction. Since the cross-sectional area of the flow path of the compressor that boosts the fuel gas is approximately proportional to the volumetric flow rate of the gas, in order to boost the cracked gas after decomposition, the flow is about twice that of the case where the pressure is boosted before cracking. A large booster (compressor) with a road cross-sectional area is required. Further, since the power of the booster for boosting the fuel gas obtained by decomposing the ammonia gas is substantially proportional to the volumetric flow rate of the gas, it is about twice the power for boosting the ammonia gas before decomposition. That is, this method increases equipment cost and running cost. On the other hand, in the present embodiment, the liquid ammonia before being supplied to the ammonia self-thermal decomposition device 51 is boosted to a pressure higher than the pressure in the combustor 11b by the ammonia booster (pump) 80, and the ammonia. The bleed air BA before being supplied to the decomposition device 50 is boosted to a pressure higher than the pressure in the combustor 11b by the bleed air booster 87. Therefore, in the present embodiment, this gas can be guided to the combustor 11b without boosting the pressure of the gas after decomposing ammonia. Moreover, in the present embodiment, since the bleed air BA whose pressure is higher than that of the atmosphere is boosted by the bleed air booster 87, the load on the bleed air booster 87 is small. Therefore, in the present embodiment, the equipment cost and the running cost can be suppressed from the above viewpoints as well.

In the present embodiment, the heat of the decomposition gas DG generated in the ammonia decomposition facility X is used as a heat source for heating ammonia and as a heat source for heating water from the ammonia separation tower 75 into steam. .. Therefore, in the present embodiment, the equipment cost and the running cost can be suppressed as compared with the case where the heat outside the ammonia decomposition equipment X is used as these heat sources.

"Modification example"
In this embodiment, the gas turbine rotor 11d and the steam turbine rotor 34 are connected. However, the gas turbine rotor 11d and the steam turbine rotor 34 may not be connected. In this case, a generator is connected to each of the gas turbine rotor 11d and the steam turbine rotor 34.

The steam turbine equipment 30 in the present embodiment has three types of steam turbines 31, 32, 33 in which the pressure of the inflow steam is different from each other. However, the steam turbine equipment may have only one type of steam turbine as the steam turbine. In this case, the steam generation system of the exhaust heat recovery boiler need only have one type of steam generation system as the steam generation system for generating steam for driving the steam turbine.

In the present embodiment, as a method of removing ammonia from the decomposition gas DG, a method of bringing the decomposition gas DG into contact with water is adopted in the absorption tower 64. However, a pressure fluctuation adsorption method (PSA) may be adopted as a method for removing ammonia from the decomposed gas DG. The pressure fluctuation adsorption method is characterized by being a dry method. However, in this method, it is necessary to pay attention to the pressure fluctuation at the time of switching between suction and desorption.

In the present embodiment, the water accumulated in the lower part of the separation tower 75 in the ammonia separator 72 is heated by the water heater 77 by heat exchange with the decomposition gas DG. However, the steam generated by the exhaust heat recovery boiler 20 may be used as the heat medium for heat exchange with the water. In this case, for example, the medium-pressure steam line 42 through which the medium-pressure steam IS flows, or the reheated steam line 43 through which the reheated steam RS flows, and the heat medium inlet of the water heater 77 are connected by a medium line. The pressure steam IS or the reheat steam RS may be used as a heat medium for heat exchange with water. In this case, if the latent heat of vaporization of steam is used, a relatively small flow rate of steam is sufficient, so that the heat transfer area of the water heater 77 can be reduced. However, in this case, since a part of the steam from the exhaust heat recovery boiler 20 is used, the output of the steam turbine driven by the steam from the exhaust heat recovery boiler 20 may decrease, and the plant efficiency may decrease. ..

In this embodiment, the water heater 77 is arranged outside the separation tower 75 in the ammonia separator 72. That is, in the present embodiment, the water accumulated in the lower part of the separation tower 75 is drawn out to the outside, and this water is heated by the water heater 77. However, a water heater may be arranged in the lower space of the separation tower 75 in the ammonia separator 72.

In the present embodiment, the condenser 78 is arranged outside the separation tower 75 in the ammonia separator 72. That is, in the present embodiment, the gas in the separation tower 75 is drawn to the outside, and a part of this gas is condensed by the condenser 78. However, the condenser may be arranged in the upper space in the separation tower 75 of the ammonia separator 72.

In the present embodiment, the filling method is adopted as the gas-liquid contact method in the absorption tower 64 in the ammonia absorber 62. Further, in the present embodiment, a shelf type is adopted as a gas-liquid contact method in the separation tower 75 in the ammonia separator 72. However, since there are other methods for the gas-liquid contact method, other methods may be adopted as the gas-liquid contact method in the absorption tower 64 and the separation tower 75. The multiple methods that realize the gas-liquid contact method have advantages and disadvantages in terms of equipment size, equipment capital cost, equipment maintenance cost, equipment pressure loss, equipment required power, equipment durability, etc. There is. Therefore, among a plurality of methods for realizing the liquid contact method, the optimum method may be selected according to the plant specifications, location conditions, and the like.

In this embodiment, hydrogen or natural gas is assumed as the starting fuel SF. However, as the start-up fuel SF, for example, a liquid fuel such as light oil may be used. In this case, the processed gas PG which is a gaseous fuel and the liquid fuel cannot be sent to the combustor 11b through a common pipe. Therefore, in this case, it is necessary to separately provide a pipe for supplying the liquid fuel to the combustor 11b.

In the present embodiment, after the gas turbine 11 is in steady operation, the processed gas PG is exclusively used as fuel for the combustor 11b. However, after the gas turbine 11 is in steady operation, a mixed fuel gas obtained by mixing the processed gas PG and another fuel gas such as natural gas may be used as the fuel. In this case, when the gas turbine 11 is started, only other fuel gas such as natural gas is used as fuel. In this case, since the consumption of liquid ammonia is smaller than that in the present embodiment during steady operation, the capacity and processing capacity of each device constituting the ammonia decomposition facility X constitutes the ammonia decomposition facility X of the present embodiment. It is smaller than the capacity and processing capacity of each device. Specifically, for example, the capacities of the ammonia tank T, the ammonia self-pyrolyzer 53, the ammonia separator 72, and the like are all smaller than those of the present embodiment. However, in this case, the amount of carbon dioxide in the exhaust gas EG is larger than that in the present embodiment. However, even in this case, since the processed gas PG is used as a part of the fuel during the steady operation, the amount of carbon dioxide in the exhaust gas EG is reduced as compared with the case where the natural gas is exclusively used as the fuel during the steady operation. can do.

10: Gas turbine equipment 11: Gas turbine 11a: Air compressor 11b: Combustor 11c: Turbine 11d: Gas turbine rotor 11e: Compressed air passage 12: Fuel line 13: Flow meter 14: Preheater 15: Fuel control valve 16: At startup Fuel line 20: Exhaust heat recovery boiler 21: Boiler frame 22: Low pressure steam generating system 22a: Coal saving device 22b: Evaporator 22c: Superheater 23: Medium pressure steam generating system 24: Medium pressure pump 25: Condenser System 26: High-pressure steam generation system 27: High-pressure pump 29: Stack 30: Steam turbine equipment 31: Low-pressure steam turbine 32: Medium-pressure steam turbine 33: High-pressure steam turbine 34: Steam turbine rotor 35: Condenser 36: Condensation pump 39: Generator 41: Low pressure steam line 42: Medium pressure steam line 43: Condensed steam line 44: High pressure steam line 45: Medium pressure exhaust steam line 46: High pressure exhaust steam line 47: Water supply line 49: Hot water line T: Ammonia tank X: Ammonia decomposition equipment 50: Ammonia decomposition device 51: Ammonia self-thermal decomposition device 52a: First ammonia heater 52b: Second ammonia heater 53: Ammonia self-thermal decomposition device 54: Decomposition gas line 54a: First line 54b: Second line 54c: Third line 54d: Fourth line 61: Ammonia removal device 62: Ammonia absorber 63: Decomposition gas cooler 64: Absorption tower 64p: Filling 64v: Absorption tower container 65: Water line 66: Water supply pump 67: Water cooler 72: Ammonia separator 73: Ammonia water line 74: Ammonia water heater 75: Separation tower 75v: Separation tower container 75p: Shelf stage 76: Water circulation line 77: Water heater 78: Condenser 79: Water recovery line 80: Ammonia booster 81: Ammonia supply line 82: Treated gas supply line 83: Ammonia recovery line 84: Ammonia compressor 85: Extraction air line 86: Extraction air cooler 87: Extraction air booster 88i : Cooling medium line 88o: Cooling medium recovery line 89: Fuel buffer BA: Extracted air EG: Exhaust gas LS: Low pressure steam IS: Medium pressure steam RS: Condensed steam HS: High pressure steam DG: Decomposed gas SF: Fuel PG at startup : Processed gas

Claims (14)

A gas turbine having a compressor that compresses air, a combustor that burns fuel in compressed air that is the air compressed by the compressor to generate combustion gas, and a turbine that is driven by the combustion gas. In the connected ammonia decomposition facility
An bleed air line connected to the gas turbine and a part of the compressed air flowing as bleed air,
Ammonia supply line through which ammonia flows and
It is connected to the bleed air line and the ammonia supply line, and the bleed air from the bleed air line is used as an oxidizing agent to burn a part of the ammonia from the ammonia supply line to self-decompose the ammonia. , Ammonia crackers that produce treated gas containing hydrogen and nitrogen,
A processed gas supply line that guides the processed gas generated by the ammonia decomposition device to the combustor as the fuel, and
Ammonia decomposition equipment equipped with. In the ammonia decomposition equipment according to claim 1,
An ammonia booster provided in the ammonia supply line and boosting the ammonia flowing through the ammonia supply line to a pressure higher than the pressure in the combustor.
An bleed air booster provided in the bleed air line and boosting the bleed air flowing through the bleed air line to a pressure higher than the pressure in the combustor.
Ammonia decomposition equipment equipped with. In the ammonia decomposition equipment according to claim 1 or 2.
The ammonia decomposition device is
Using the extracted air from the extracted air line as an oxidizing agent, a part of the ammonia from the ammonia supply line is burned to self-pyrolyze the ammonia to produce a decomposed gas containing hydrogen, nitrogen and residual ammonia. Ammonia self-pyrolysis device to be generated and
An ammonia removing device that removes the residual ammonia contained in the decomposition gas from the ammonia self-pyrolysis device and discharges the gas from which the residual ammonia has been removed from the decomposition gas as the processed gas.
Have,
Ammonia decomposition equipment. In the ammonia decomposition equipment according to claim 3,
The ammonia self-pyrolyzer has an ammonia heater and an ammonia self-pyrolyzer.
The ammonia heater is provided in the ammonia supply line, and heat exchanges the ammonia flowing through the ammonia supply line with the decomposition gas to heat the ammonia while cooling the decomposition gas. And
The ammonia self-pyrolyzer uses the extracted air from the bleed air line as an oxidant to burn a part of the ammonia after being heated by the ammonia heater to self-pyrolyze the ammonia. Ammonia decomposition equipment that produces the decomposition gas. In the ammonia decomposition equipment according to claim 3 or 4.
The ammonia removing device includes an ammonia absorber and an ammonia separator.
The ammonia absorber brings the decomposition gas from the ammonia self-pyrolysis apparatus into contact with water to dissolve the residual ammonia in the decomposition gas in the water, while discharging the treated decomposition gas. ,
The ammonia separator has a separation tower and a water heater.
In the separation tower, the ammonia water, which is the water in which the residual ammonia is dissolved, is brought into contact with steam, and the ammonia water is heated to separate ammonia from the ammonia water.
The water heater heats water in which ammonia is separated from the ammonia water to make steam, and then returns the steam to the separation tower.
Ammonia decomposition equipment. In the ammonia decomposition equipment according to claim 5.
The water heater is a heat exchanger that heats the water to steam by exchanging heat between the water in which ammonia is separated from the ammonia water and the decomposition gas.
Ammonia decomposition equipment. The ammonia decomposition equipment according to any one of claims 1 to 6.
With the gas turbine
A gas turbine plant equipped with. In the ammonia decomposition device, part of the ammonia is burned using the extracted air, which is a part of the compressed air that is the air compressed by the compressor of the gas turbine, as an oxidizing agent, and the ammonia is self-thermally decomposed into hydrogen. Ammonia decomposition step to generate treated gas containing nitrogen,
A processed gas supply step of using the treated gas generated in the ammonia decomposition step as fuel and guiding it to the combustor of the gas turbine, and
Ammonia decomposition method to perform. In the ammonia decomposition method according to claim 8,
An ammonia supply step of boosting the ammonia before self-pyrolysis in the ammonia decomposition step to a pressure higher than the pressure in the combustor and then supplying the boosted ammonia to the ammonia decomposition device.
An bleed air supply step in which the bleed air before being used as the oxidant in the ammonia decomposition step is pressurized to a pressure higher than the pressure in the combustor, and then the bleed air after the pressure is supplied to the ammonia decomposition apparatus. When,
Ammonia decomposition method to perform. In the ammonia decomposition method according to claim 8 or 9.
The ammonia decomposition step is
Using the extracted air before being used as the oxidant as an oxidant, a part of the ammonia is burned to self-pyrolyze the ammonia to generate a decomposition gas containing hydrogen, nitrogen and residual ammonia. Ammonia self-pyrolysis process and
An ammonia removal step of removing the residual ammonia from the decomposition gas and discharging the gas from which the residual ammonia has been removed from the decomposition gas as the treated gas.
including,
Ammonia decomposition method. In the ammonia decomposition method according to claim 10,
The ammonia self-pyrolysis step includes an ammonia preheating step and an ammonia self-pyrolysis execution step.
In the ammonia preheating step, the ammonia and the decomposition gas are heat-exchanged to heat the ammonia while cooling the decomposition gas.
In the ammonia self-pyrolysis execution step, a part of the ammonia after being heated in the ammonia preheating step is burned by using the extracted air before being used as the oxidizing agent as an oxidizing agent, and the ammonia is self-heated. Decompose to generate the decomposed gas,
Ammonia decomposition method. In the ammonia decomposition method according to claim 10 or 11.
The ammonia removal step includes an ammonia absorption step and an ammonia separation step.
In the ammonia absorption step, the decomposition gas obtained in the execution of the ammonia self-pyrolysis step is brought into contact with water to dissolve the residual ammonia in the decomposition gas in water, while the treated gas is dissolved. Discharge,
The ammonia separation step includes a separation execution step and a water heating step.
In the separation execution step, ammonia water, which is water in which the residual ammonia is dissolved, is brought into contact with water vapor, and ammonia is evaporated and separated from the ammonia water.
In the water heating step, the water in which ammonia is separated from the ammonia water is heated to obtain steam used in the separation execution step.
Ammonia decomposition method. In the ammonia decomposition method according to claim 12,
In the water heating step, the water in which ammonia is separated from the ammonia water and the decomposition gas are heat-exchanged to heat the water into steam.
Ammonia decomposition method. In the ammonia decomposition method according to any one of claims 8 to 13.
The residual ammonia concentration in the treated gas is adjusted to a concentration at which the nitrogen oxide concentration in the exhaust gas exhausted from the gas turbine becomes less than a desired concentration.
Ammonia decomposition method.

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