An ammonia gas turbine fuel supply system based on dynamic adjustment of cracking ratio

Abstract

The present application relates to the technical field of ammonia fuel gas turbine fuel supply, and particularly relates to an ammonia gas turbine fuel supply system based on dynamic adjustment of cracking proportion. The technical scheme comprises a liquid ammonia storage tank connected to a gasifier for supplying liquid ammonia to the gasifier; the gasifier is used for gasifying liquid ammonia into ammonia gas, and an ammonia gas outlet of the gasifier is provided with a shunt node; the shunt node is respectively connected to a cracking branch, a direct supply branch and a heat supply ammonia gas branch; the cracking branch is provided with a cracker, and an outlet of the cracking branch is connected to a mixing buffer tank. Through the three branch shunts after gasification, independent decoupling of gasification heat supply and cracking heat supply, cooperation of two-stage cooling and mixing buffer, and integrated design of purge and accommodation, the present application realizes dynamic accurate adjustment of cracking proportion in the ammonia gas turbine fuel supply process, rapid response and stable supply of fuel composition, and comprehensive improvement of system energy efficiency and safety and environmental protection performance.

Description

Technical Field

[0001] This invention relates to the field of ammonia fuel gas turbine fuel supply technology, and in particular to an ammonia fuel gas turbine fuel supply system based on dynamic adjustment of cracking ratio. Background Technology

[0002] Ammonia, as a carbon-free fuel, has advantages such as being carbon-free, easy to liquefy and store, having a high volumetric energy density, and being able to be produced using renewable energy sources. It has broad application prospects in gas turbine power generation, distributed energy, marine propulsion, and industrial thermal energy systems. Compared with natural gas and hydrogen, ammonia has lower storage and transportation costs. Liquid ammonia can be liquefied at -33°C under normal pressure, or kept liquid by pressurizing it to approximately 0.8 MPa at room temperature, facilitating large-scale storage and long-distance transportation.

[0003] However, using ammonia as a fuel for gas turbines presents numerous technical challenges. Ammonia has a high ignition energy, but its flame propagation speed is much lower than that of natural gas and hydrogen. Its combustible range is narrow, with a volume fraction in air of approximately 15%–28%. It also exhibits poor combustion stability and is prone to unburned ammonia escape and nitrogen oxide emissions during combustion. Under gas turbine start-up, low-load, and rapid load change conditions, using ammonia alone can easily lead to ignition difficulties, flame instability, combustion oscillations, and even flameout, severely restricting the engineering application of ammonia in gas turbines.

[0004] Partially cracking ammonia to produce hydrogen and nitrogen is an effective technical route to improve ammonia combustion performance. The catalytic cracking reaction of ammonia is 2NH3→N2+3H2, which is a strongly endothermic reaction (standard enthalpy change ΔH°=+91.2kJ / mol), requiring high temperature (typically 400℃~800℃) and the presence of a catalyst. The hydrogen produced by cracking has the characteristics of low ignition energy, fast flame propagation speed, and wide combustibility. Mixing hydrogen-containing cracked gas with uncracked ammonia as fuel can significantly improve the reactivity and flame stability of the mixed fuel, thereby improving the start-up performance and variable load adaptability of the gas turbine.

[0005] However, ammonia cracking is a strongly endothermic reaction, requiring a continuous supply of a large amount of heat to the cracker. Cracking all ammonia fuel would significantly increase the system's heating load and equipment investment, reducing the overall energy efficiency and economic viability. Therefore, partial cracking, on-demand cracking, and dynamic adjustment of the cracking ratio are of great significance for the engineering application of ammonia gas turbine fuel supply systems.

[0006] Several existing technologies involve fuel supply systems for ammonia-fueled gas turbines. For example, Chinese patent CN223578042U generates hydrogen-containing fuel through partial ammonia catalytic cracking and uses combustion flue gas and gas turbine exhaust to heat the gasification components, thus improving the combustion activity of ammonia fuel and the system's energy utilization rate to some extent. However, this scheme involves strong coupling between gasification heating, cracking heating, and fuel supply, with each thermodynamic process mutually constraining the others. It also lacks the dynamic adjustment capability for the ratio of directly supplied ammonia to cracked gas, making it difficult to adapt to the rapid load changes required by the gas turbine.

[0007] Chinese patent CN121676138A employs a combination of plasma pyrolysis equipment, pyrolysis devices, and staged combustion chambers, which is beneficial for improving the start-up performance and stable operation of pure ammonia fuel. However, the plasma in this scheme is mainly used for the ammonia pyrolysis process itself, and the system focuses on the coupled control of staged combustion and pyrolysis. It does not adequately consider the buffering and stabilization of mixed fuels and the rapid and precise adjustment of target hydrogen content, resulting in a limited dynamic response speed of the fuel composition.

[0008] Chinese patent CN119435210A utilizes the exhaust heat source of a gas turbine for ammonia cracking under normal pressure, which can improve the waste heat utilization efficiency of the system. However, the cracking process is greatly affected by changes in the exhaust temperature and flow rate of the gas turbine. When the gas turbine operates under varying conditions, changes in exhaust parameters will directly lead to fluctuations in the cracking rate, which in turn will cause changes in the fuel composition. This limits the system's adaptability to varying operating conditions and its ability to independently control the fuel composition.

[0009] In addition, the above-mentioned existing technologies generally have the following shortcomings: (1) lack of mixing buffer and pressure stabilization links, the flow and pressure fluctuations of cracked gas and direct ammonia are easily transmitted directly to the fuel inlet of the gas turbine, affecting combustion stability; (2) insufficient treatment of residual ammonia gas under shutdown and emergency cut-off conditions, and direct discharge of residual ammonia in the system will bring safety risks and environmental pollution problems; (3) single heating mode of cracker, with insufficient heating under start-up conditions and lagging heat regulation under variable conditions; (4) gasifier heating and cracker heating have not been effectively decoupled, and mutual interference between different heat loads affects the operational stability of the system.

[0010] Therefore, this application proposes an ammonia gas turbine fuel supply system based on dynamic adjustment of cracking ratio. Summary of the Invention

[0011] The purpose of this invention is to address the problems existing in the background art by proposing an ammonia gas turbine fuel supply system based on dynamic adjustment of the cracking ratio.

[0012] The technical solution of this invention: A fuel supply system for an ammonia gas turbine based on dynamic adjustment of cracking ratio, comprising:

[0013] A liquid ammonia storage tank, the liquid ammonia storage tank being connected to a vaporizer for supplying liquid ammonia to the vaporizer;

[0014] The vaporizer is used to vaporize liquid ammonia into ammonia gas, and the ammonia gas outlet of the vaporizer is provided with a diversion node;

[0015] The diversion nodes are respectively connected to the pyrolysis branch, the direct supply branch, and the heating ammonia branch;

[0016] The cracking branch is equipped with a cracker, and the outlet of the cracking branch is connected to a mixing buffer tank. The cracking branch is used to catalytically crack at least a portion of the ammonia into hydrogen-containing cracked gas and deliver it to the mixing buffer tank.

[0017] The direct supply branch is connected to the mixing buffer tank and is used to directly deliver uncracked ammonia gas to the mixing buffer tank;

[0018] The heating ammonia branch is connected to the pyrolyzer heating device, which is thermally coupled to the pyrolyzer to provide the pyrolyzer with the heat required for pyrolysis, and the heating ammonia branch is not connected to the mixing buffer tank.

[0019] The outlet of the mixing buffer tank is connected to the fuel inlet of the ammonia gas turbine, and is used to mix the hydrogen-containing cracked gas with the uncracked ammonia gas and then supply it to the ammonia gas turbine.

[0020] An inert gas purging unit is provided, wherein the purging discharge end of the inert gas purging unit is connected to the pyrolysis heating device, and is used to introduce the ammonia-containing residual gas discharged during purging into the pyrolysis heating device for disposal in the event of system shutdown or emergency cut-off.

[0021] A control unit is communicatively connected to at least the pyrolysis branch, the direct supply branch, and the ammonia gas turbine. The control unit is configured to dynamically adjust the flow ratio of the pyrolysis branch and the direct supply branch according to the operating conditions of the ammonia gas turbine.

[0022] Optionally, it also includes a booster pump and a liquid ammonia metering system, wherein the liquid ammonia storage tank is connected to the vaporizer via the booster pump and the liquid ammonia metering system.

[0023] Optionally, the pyrolysis branch is further provided with a pyrolysis branch ammonia metering component, the direct supply branch is provided with a direct supply branch ammonia metering component, and the heating ammonia branch is provided with a heating ammonia metering component. The control unit is communicatively connected to the pyrolysis branch ammonia metering component, the direct supply branch ammonia metering component, and the heating ammonia metering component, respectively, for adjusting the ammonia flow rate of each branch.

[0024] Optionally, the molar flow rate of ammonia entering the cracking branch is denoted as... The molar flow rate of ammonia entering the direct supply branch is recorded as... The molar flow rate of ammonia entering the heating ammonia branch is denoted as . pyrolysis ratio Defined as: ,in Excluding the cracking ratio .

[0025] Optionally, the ammonia cracking rate at the pyrolyzer outlet is denoted as X, and the control unit calculates the theoretical composition of the main fuel mixture in the mixing buffer tank based on R and X, wherein the hydrogen gas integral... satisfy: When X reaches the preset complete pyrolysis threshold, the control unit performs feedforward calculations based on X≈.

[0026] Optionally, it also includes a waste heat boiler, the flue gas inlet of which is connected to the exhaust gas passage of the ammonia gas turbine, and the steam outlet of which is connected to the steam heat exchange passage of the gasifier via a steam regulating valve, for using the exhaust waste heat of the ammonia gas turbine to provide gasification heat for the gasifier.

[0027] Optionally, the pyrolysis unit is a plasma-assisted ammonia combustion chamber, which includes a plasma power supply and a combustion chamber. The heating ammonia branch is connected to the fuel inlet of the combustion chamber, and the combustion chamber is thermally coupled to the pyrolysis unit.

[0028] Optionally, the cracking branch is further provided with a cooling device, which is located downstream of the cracker and is used to cool the hydrogen-containing cracked gas at the cracker outlet before sending it into the mixing buffer tank.

[0029] The cooling device includes a waste heat recovery heat exchanger and a second-stage cooler. The cold side of the waste heat recovery heat exchanger is located upstream of the pyrolyzer, and the hot side of the waste heat recovery heat exchanger is located downstream of the pyrolyzer. The second-stage cooler is located downstream of the hot side outlet of the waste heat recovery heat exchanger.

[0030] Optionally, the control unit receives the load signal and / or combustion status signal of the ammonia gas turbine, determines the target hydrogen content based on the signal, and then calculates the target cracking ratio based on the target hydrogen content;

[0031] The inert gas purging unit includes a nitrogen source or a carbon dioxide source and a purging valve group. The control unit opens the purging valve group during shutdown or emergency shutdown to replace and discharge the residual ammonia-containing gas in the pyrolysis branch, direct supply branch and mixing buffer tank and introduce it into the pyrolysis heating device.

[0032] Optionally, the mixing buffer tank is provided with a mixing enhancement structure, which is selected from at least one of a static mixer, a baffle plate, a porous distributor, and a swirling jet.

[0033] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0034] This application sets up a cracking branch, a direct supply branch, and a heating ammonia branch at the gasifier outlet, with the flow rates of each branch regulated by independent metering components. The heating ammonia branch does not enter the mixing buffer tank and is not included in the main fuel composition calculation, fundamentally avoiding disturbances to the fuel composition caused by changes in the flow rate of heating ammonia, resulting in more precise and reliable control.

[0035] The control unit dynamically adjusts the cracking ratio according to different operating conditions such as start-up, low load, increased load, steady state, decreased load, unstable combustion, and shutdown, and adjusts the fuel hydrogen content as needed. While ensuring combustion stability, it reduces the cracking heat load and achieves an optimal balance between combustion performance and system energy consumption.

[0036] A feedforward calculation model is established using the stoichiometric relationship of the ammonia cracking reaction to quickly calculate the target cracking ratio and avoid the lag caused by relying solely on feedback control. At the same time, feedback correction is performed by component sensors in the mixing buffer tank to eliminate the influence of disturbances such as cracking rate fluctuations, thus achieving a balance between rapid response and precise control.

[0037] The gasifier is heated by high-temperature steam generated from the waste heat of the gas turbine exhaust in the waste heat boiler, while the pyrolyzer is independently heated by the plasma-assisted ammonia combustion chamber. The heat loads of the two parts are controlled independently and do not interfere with each other, which improves the flexibility and stability of operation under different conditions.

[0038] Waste heat from ammonia gas turbine exhaust is used to generate high-temperature steam via a waste heat boiler, indirectly heating the gasifier and achieving waste heat recovery. Using steam as the heat carrier avoids direct contact between flue gas and ammonia media and catalyst, maintaining high heat exchange efficiency while improving system safety.

[0039] The pyrolysis branch is equipped with a waste heat recovery heat exchanger and a second-stage cooler. The waste heat recovery heat exchanger achieves primary cooling of the high-temperature pyrolysis gas and preheating of the ammonia gas to be pyrolyzed; the second-stage cooler compensates for the cooling capacity under low pyrolysis ratio or heat exchange imbalance conditions, ensuring that the temperature of the pyrolysis gas entering the mixing buffer tank is lower than the upper limit of the sensor's allowable operating temperature, thus avoiding sensor inaccuracy and excessive heat load on the pipeline.

[0040] The plasma-assisted ammonia combustion chamber serves as both a heat source for the pyrolyzer and a device for disposing of residual ammonia-containing gas during shutdown purging. Plasma-assisted combustion ensures stable ignition and combustion of ammonia under a wide range of operating conditions. The functions of heating and safe disposal work together, reducing the number of devices and improving system compactness and safety.

[0041] The mixing buffer tank mixes and homogenizes hydrogen-containing cracked gas and directly supplied ammonia gas, and buffers pressure to suppress the transmission of upstream flow and pressure fluctuations to the gas turbine, reduce combustion chamber equivalence ratio fluctuations, and improve combustion stability under start-up, low load, and variable load conditions.

[0042] The inert gas purging unit's discharge end is connected to the plasma-assisted ammonia combustion chamber. During shutdown or emergency shutdown, the ammonia-containing residual gas discharged is directly introduced into the combustion chamber for disposal, avoiding direct emission into the atmosphere. In the initial purging phase, the combustion chamber is maintained by supplied ammonia gas; in the later stages, the residual ammonia-containing gas itself sustains its operation, ensuring a safe and stable transition.

[0043] The gasifier is equipped with an auxiliary start-up heating unit to provide gasification heat during the system start-up phase and when the steam parameters of the waste heat boiler do not meet the standards, ensuring normal cold start-up; after the waste heat boiler is running normally, it smoothly switches to waste heat supply to achieve continuous and stable combustion under all operating conditions.

[0044] In summary, this invention achieves dynamic and precise adjustment of the cracking ratio, rapid response and stable supply of fuel composition, and comprehensive improvement of system energy efficiency and safety and environmental performance by splitting the gasification into three branches after gasification, independently decoupling gasification heating and cracking heating, coordinating two-stage cooling and mixing buffer, and integrating purging and absorption design during the combustion process of ammonia gas turbine. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the structure of an ammonia gas turbine fuel supply system based on dynamic adjustment of cracking ratio according to the present invention.

[0046] Figure 2 The graph shows the theoretical relationship between different cracking ratios R and the volume fractions of H2, N2, and NH3 in the mixed fuel under the condition that the ammonia cracking rate X≈1.

[0047] Reference numerals in the attached diagram: 1. Liquid ammonia storage tank; 2. Booster pump; 3. Liquid ammonia metering system; 4. Vaporizer; 5a. Ammonia metering component for pyrolysis branch; 5b. Ammonia metering component for direct supply branch; 5c. Ammonia metering component for heating; 5d. Air metering component; 6. Waste heat recovery heat exchanger; 7. Pyrolysis unit; 8. Second-stage cooler; 9. Air compressor; 10. Pyrolysis unit heating device; 11. Mixing buffer tank; 12. Ammonia gas turbine; 13. Inert gas purging unit; 14. Control unit; 15. Waste heat boiler. Detailed Implementation

[0048] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0049] Example: Figure 1 As shown, this invention proposes a fuel supply system for an ammonia gas turbine based on dynamic adjustment of the cracking ratio. The system will be described in detail below.

[0050] I. System Overall Architecture and Basic Workflow

[0051] like Figure 1 As shown, the ammonia gas turbine fuel supply system based on dynamic adjustment of cracking ratio provided by the present invention includes: a liquid ammonia storage tank 1, a booster pump 2, a liquid ammonia metering system 3, a vaporizer 4, ammonia metering component 5a for the cracking branch, ammonia metering component 5b for the direct supply branch, ammonia metering component 5c for heating, an air metering component 5d, a waste heat recovery heat exchanger 6, a cracker 7, a second-stage cooler 8, an air compressor 9, a cracker heating device 10, a mixing buffer tank 11, an ammonia gas turbine 12, an inert gas purging unit 13, a control unit 14, and a waste heat boiler 15. In this embodiment, the liquid ammonia storage tank 1 is located at the liquid ammonia supply station upstream of the system, used to store liquid ammonia under normal pressure and low temperature or normal temperature and pressurized conditions. Its liquid ammonia outlet is connected to the inlet of the booster pump 2 through a pipeline. The booster pump 2 is arranged between the liquid ammonia storage tank 1 and the vaporizer 4. The outlet of booster pump 2 is connected to the inlet of liquid ammonia metering system 3 via a pipeline. The outlet of liquid ammonia metering system 3 is connected to the ammonia medium inlet of vaporizer 4 via a pipeline. Liquid ammonia flows sequentially through booster pump 2 and liquid ammonia metering system 3 along the supply pipeline before entering vaporizer 4. Vaporizer 4 is located in the middle of the ammonia supply system and is an indirect heat exchange type vaporizer. It has an isolated ammonia medium side and a steam heat exchange channel inside, and the two transfer heat through the heat exchange wall without direct contact between the media. The ammonia medium inlet of vaporizer 4 is located at one end of its ammonia medium side, and the ammonia medium outlet is located at the other end with a branch node. This branch node connects the ammonia outlet of vaporizer 4 to three downstream branches. The inlet of the steam heat exchange channel of vaporizer 4 is connected to the steam outlet of waste heat boiler 15 via a steam pipeline and a steam regulating valve. The outlet of the steam heat exchange channel is connected to the condensate recovery unit or the feedwater inlet of waste heat boiler 15 via a pipeline.

[0052] In this embodiment, the ammonia outlet of the vaporizer 4 is connected to the pyrolysis branch, the direct supply branch, and the heating ammonia branch. The pyrolysis branch, starting from this branch, sequentially includes an ammonia metering component 5a and a cold-side channel of the waste heat recovery heat exchanger 6 along the ammonia flow direction. The cold-side outlet of the waste heat recovery heat exchanger 6 is connected to the inlet of the pyrolysis unit 7. The pyrolysis unit 7 is located in the middle to rear section of the pyrolysis branch. Its outlet is connected to the hot-side inlet of the waste heat recovery heat exchanger 6 via a pipeline. The hot-side outlet of the waste heat recovery heat exchanger 6 is connected to the inlet of the second-stage cooler 8 via a pipeline. The outlet of the second-stage cooler 8 is connected to the pyrolysis gas inlet of the mixing buffer tank 11 via a pipeline. The pyrolysis unit 7 and the waste heat recovery heat exchanger 6 are arranged adjacent to each other in space to minimize the length of the high-temperature pyrolysis gas pipeline.

[0053] A direct supply branch ammonia metering component 5b is installed along the ammonia flow direction from the outlet branch node of the vaporizer 4. Its outlet is directly connected to the direct supply ammonia inlet of the mixing buffer tank 11 via a pipeline. This branch does not pass through the pyrolyzer 7. A heating ammonia branch ammonia metering component 5c is installed along the ammonia flow direction from the outlet branch node of the vaporizer 4. Its outlet is connected to the ammonia inlet of the pyrolyzer heating device 10 via a pipeline. An air compressor 9 is arranged near the pyrolyzer heating device 10. Its outlet is connected to the inlet of the air metering component 5d via a pipeline. The outlet of the air metering component 5d is connected to the oxidant inlet of the pyrolyzer heating device 10 via a pipeline. The pyrolyzer heating device 10 and the pyrolyzer 7 are arranged spatially adjacent to each other, and a thermal coupling channel is provided between them.

[0054] The mixing buffer tank 11 is located downstream of the pyrolysis branch and the direct supply branch, and its outlet is connected to the fuel inlet of the ammonia gas turbine 12 via a pipeline. The ammonia gas turbine 12 is located at the power output position of the system, and its flue gas passage is connected to the flue gas inlet of the waste heat boiler 15 via a pipeline. The waste heat boiler 15 is located downstream of the ammonia gas turbine 12, and its steam outlet is connected to the steam heat exchange passage inlet of the gasifier 4 via a steam pipeline and a steam regulating valve.

[0055] The inert gas purging unit 13 is arranged at an appropriate position in the system pipeline. Its purging gas outlet is connected to the pyrolysis branch, the direct supply branch and the purging gas inlet of the mixing buffer tank 11 through purging pipes and purging valve groups, respectively. The purging discharge end is connected to the ammonia-containing residual gas inlet of the pyrolysis heating device 10 through a pipe.

[0056] The control unit 14 is a programmable logic controller, a distributed control system, or an embedded controller, and is located in the control room of the system. It is connected to the ammonia metering component 5a of the cracking branch, the ammonia metering component 5b of the direct supply branch, the ammonia metering component 5c of the heating branch, the air metering component 5d, the air compressor 9, the cracker heating device 10, the mixing buffer tank 11, the ammonia gas turbine 12, and the waste heat boiler 15 via signal lines.

[0057] Liquid ammonia storage tank 1 is used to store liquid ammonia under normal pressure and low temperature or normal temperature and pressurization conditions. The liquid ammonia outlet of liquid ammonia storage tank 1 is connected to the inlet of booster pump 2 via a pipeline. The outlet of booster pump 2 is connected to liquid ammonia metering system 3. The outlet of liquid ammonia metering system 3 is connected to the ammonia medium inlet of vaporizer 4. Booster pump 2 pressurizes the liquid ammonia from the storage tank pressure to the required operating pressure of the system. The pressurized pressure is typically 1.0 MPa to 5.0 MPa, depending on the fuel inlet pressure requirements of ammonia gas turbine 12. Liquid ammonia metering system 3 is used to measure and control the total liquid ammonia flow rate entering vaporizer 4. Accurate metering can be achieved using a mass flow meter or volumetric flow meter in conjunction with temperature and pressure compensation.

[0058] The vaporizer 4 is an indirect heat exchange type vaporizer, internally equipped with an isolated ammonia medium side and a steam heat exchange channel. Heat transfer between the two is achieved through the heat exchange walls, without direct contact between the media. The ammonia medium side inlet of the vaporizer 4 is connected to the outlet of the liquid ammonia metering system 3, and the ammonia medium side outlet is the ammonia gas outlet, where a flow branching node is located. The steam heat exchange channel inlet of the vaporizer 4 is connected to the steam outlet of the waste heat boiler 15, and the steam heat exchange channel outlet is connected to the condensate recovery unit or the feedwater inlet of the waste heat boiler 15. In the vaporizer 4, liquid ammonia absorbs heat transferred from the steam heat exchange channel and undergoes a phase change, transforming into ammonia gas. The outlet ammonia gas temperature is typically controlled slightly above the saturation temperature of liquid ammonia at the current pressure.

[0059] The ammonia outlet of vaporizer 4 is divided into three branches: a cracking branch, a direct supply branch, and a heating ammonia branch. The branch can be implemented using a tee fitting, a branch header, or a multi-channel distribution valve. In the cracking branch, the ammonia first undergoes flow measurement and regulation via the cracking branch ammonia metering component 5a, then enters the cold-side inlet of the waste heat recovery heat exchanger 6. The cold-side outlet of the waste heat recovery heat exchanger 6 connects to the inlet of the cracker 7; the outlet of the cracker 7 connects to the hot-side inlet of the waste heat recovery heat exchanger 6; the hot-side outlet of the waste heat recovery heat exchanger 6 connects to the inlet of the second-stage cooler 8; and the outlet of the second-stage cooler 8 connects to the cracked gas inlet of the mixing buffer tank 11. In the direct supply branch, after flow measurement and regulation via the direct supply branch ammonia metering component 5b, the ammonia is directly fed into the direct supply ammonia inlet of the mixing buffer tank 11 without passing through the cracker 7. In the heating ammonia branch, ammonia gas is fed into the ammonia inlet of the pyrolysis heating unit 10 after the flow rate is measured and regulated by the heating ammonia metering component 5c. The air compressor 9 compresses the ambient air and sends it into the oxidant inlet of the pyrolysis heating unit 10 via the air metering component 5d.

[0060] The cracker 7 is filled with ammonia cracking catalyst, such as ruthenium-based, nickel-based, iron-based, or cobalt-based catalysts, which can be granular, honeycomb-shaped, or monolithic. The operating temperature of the cracker 7 is determined by the type of catalyst used; for example, ruthenium-based catalysts can operate in the range of 400℃ to 550℃, while nickel-based catalysts typically require 650℃ to 800℃. The cracker 7 can be configured as a fixed-bed reactor, a fluidized-bed reactor, or a tubular reactor. In the cracker 7, ammonia undergoes a catalytic cracking reaction on the catalyst surface: 2NH3 → N2 + 3H2. This reaction is strongly endothermic and requires a continuous supply of heat to maintain the reaction temperature. The hydrogen-containing cracked gas exiting the cracker 7 is a mixture of hydrogen, nitrogen, and uncracked ammonia, typically at a temperature of 400℃ to 800℃. This high-temperature hydrogen-containing cracked gas enters the hot side of the waste heat recovery heat exchanger 6, where it exchanges heat with the ammonia to be cracked on the cold side. This process both initially cools the high-temperature cracked gas and preheats the ammonia to be cracked, achieving waste heat recovery. After being initially cooled by the waste heat recovery heat exchanger 6, the cracked gas enters the second-stage cooler 8 for further cooling to the target temperature range before being sent to the mixing buffer tank 11.

[0061] The mixing buffer tank 11 receives hydrogen-containing cracked gas from the cracking branch and uncracked ammonia gas from the direct supply branch. After mixing, homogenization, and pressure stabilization within the tank, the mixture is delivered to the fuel inlet of the ammonia gas turbine 12 via the outlet pipeline. In the ammonia gas turbine 12, the main fuel mixture is mixed with compressed air and combusted. The resulting high-temperature, high-pressure gas drives the turbine, outputting mechanical work or electricity. The high-temperature flue gas discharged from the ammonia gas turbine 12 enters the flue gas inlet of the waste heat boiler 15. The waste heat boiler 15 absorbs the waste heat from the flue gas, heating the feedwater to generate high-temperature steam. This steam then enters the steam heat exchange channel of the vaporizer 4 via steam pipes and steam regulating valves, providing heat for the vaporization of liquid ammonia. The steam after heat exchange condenses into condensate, which is then recovered by the condensate recovery unit or returned to the feedwater inlet of the waste heat boiler 15 for recycling. This forms a three-stage indirect heat exchange structure with isolation between the flue gas side, steam side, and ammonia medium side, preventing direct contact between the flue gas and the ammonia medium.

[0062] The inert gas purging unit 13 includes an inert gas source, a purging valve assembly, and a purging control pipeline. The inert gas source includes a nitrogen cylinder assembly, a nitrogen generator, or a carbon dioxide source. The purging gas outlet of the inert gas purging unit 13 is connected to the purging gas inlets of the pyrolysis branch, the direct supply branch, and the mixing buffer tank 11, while the purging discharge end is connected to the ammonia-containing residual gas inlet of the pyrolysis heating device 10. The control unit 14 is a programmable logic controller, a distributed control system, or an embedded controller, and it is communicatively connected to the ammonia metering assembly 5a of the pyrolysis branch, the ammonia metering assembly 5b of the direct supply branch, the heating ammonia metering assembly 5c, the air metering assembly 5d, the air compressor 9, the pyrolysis heating device 10, the mixing buffer tank 11, the ammonia gas turbine 12, and the waste heat boiler 15.

[0063] II. Operation of the vaporizer and steam heating system.

[0064] The flue gas inlet of the waste heat boiler 15 is connected to the exhaust gas passage of the ammonia gas turbine 12. The flue gas temperature discharged from the ammonia gas turbine 12 is typically 400℃~600℃. After entering the waste heat boiler 15, the flue gas flows sequentially through the heat exchanger section, evaporator section, and economizer section, transferring heat to the water / steam system. The feedwater for the waste heat boiler 15 is supplied by a feedwater pump, preheated by the economizer, and then enters the steam drum or evaporator to absorb heat from the flue gas and generate saturated steam or superheated steam. The steam temperature can be set according to the liquid ammonia vaporization pressure and vaporization load, and in one embodiment, it is 120℃ to 250℃.

[0065] The steam outlet of the waste heat boiler 15 is connected to the inlet of the steam heat exchange channel of the gasifier 4 via a steam pipe and a steam regulating valve. The steam regulating valve, controlled by the control unit 14, is used to regulate the steam flow rate entering the gasifier 4, thereby controlling the heat supply and outlet ammonia temperature of the gasifier 4. Steam flows in the steam heat exchange channel of the gasifier 4, transferring heat to the ammonia medium side through the heat exchange wall. The liquid ammonia absorbs the heat and vaporizes. The steam after heat exchange condenses into condensate, and the condensate outlet is connected to the condensate recovery unit or returned to the feedwater inlet of the waste heat boiler 15 via a condensate pump.

[0066] During the start-up phase, the ammonia gas turbine 12 is not yet running or has only been running for a short time, and the steam temperature or pressure of the waste heat boiler 15 has not yet reached the preset gasification conditions required by the gasifier 4. At this time, the control unit 14 activates the auxiliary start-up heating unit to supply heat to the gasifier 4. The auxiliary start-up heating unit can be an electric heater, a thermal oil heat exchanger, a steam accumulator, or an external steam interface. The electric heater is installed inside the gasifier 4 or integrated with the gasifier 4. The thermal oil heat exchanger is heated through an external thermal oil system. The steam accumulator utilizes pre-stored steam heat or is temporarily supplied by the plant's public steam network through an external steam interface. When the ammonia gas turbine 12 enters stable operation, and the steam temperature and pressure of the waste heat boiler 15 reach or exceed the preset threshold, the control unit 14 gradually opens the steam regulating valve and simultaneously reduces the heating power of the auxiliary start-up heating unit, achieving a smooth switch from auxiliary heating to waste heat steam heating. Under certain transitional or abnormal operating conditions, the control unit 14 can also use a combination of waste heat steam and auxiliary start-up heating unit to ensure the stability of the ammonia temperature at the outlet of the vaporizer 4.

[0067] The control unit 14, based on parameters such as the ammonia temperature, ammonia pressure, liquid ammonia flow rate at the outlet of the gasifier 4, and the steam temperature and steam pressure of the waste heat boiler 15, achieves closed-loop control of the heat supply to the gasifier 4 by adjusting the opening of the steam regulating valve, the feedwater flow rate, or the power of the auxiliary heating unit. The steam generated by the waste heat boiler 15 is only used for heating the liquid ammonia vaporization of the gasifier 4 and is not directly used for heating the pyrolysis unit 7. That is, the waste heat from the gas turbine flue gas is only used to heat the gasifier 4 through high-temperature steam and is not used as a direct pyrolysis heat source for the pyrolysis unit 7.

[0068] III. Definition of Cracking Ratio and Calculation of Fuel Composition.

[0069] Let the molar flow rate of ammonia entering the ammonia metering unit 5a in the cracking branch be... The ammonia molar flow rate entering the ammonia metering unit 5b of the direct supply branch is: The molar flow rate of ammonia entering the metering component 5c of the heating ammonia branch is: . The ammonia gas represented by this gas enters the pyrolysis heating unit 10 for combustion and heating, and does not enter the mixing buffer tank 11. Therefore, it does not participate in the composition of the main fuel mixture supplied to the ammonia gas turbine 12. The pyrolysis ratio R is defined as the ratio of the ammonia flow rate in the pyrolysis branch to the sum of the ammonia flow rates in the pyrolysis branch and the direct supply branch. Its value range is 0≤R≤1.

[0070] Let X be the ammonia cracking rate at the outlet of cracker 7, defined as the proportion of ammonia entering cracker 7 that is converted into hydrogen and nitrogen, with a value ranging from 0 ≤ X ≤ 1. Based on the stoichiometric relationship of the ammonia cracking reaction, 2NH3 → N2 + 3H2, the volume fraction of each component in the main fuel mixture in mixing buffer tank 11 can be expressed as:

[0071] Hydrogen gas integral:

[0072] Nitrogen gas integral:

[0073] Ammonia gas integral:

[0074] When the ammonia cracking rate X at the outlet of cracker 7 reaches the preset complete cracking threshold, i.e., X≥0.95, control unit 14 can perform feedforward approximation calculation based on X≈1. At this time, the above formula simplifies to:

[0075]

[0076]

[0077]

[0078] The target hydrogen gas integral number is In this case, the control unit 14 can calculate the target pyrolysis ratio based on the current pyrolysis rate X: when X≈1,

[0079]

[0080] When X is below the preset threshold

[0081]

[0082] The target cracking ratio is indicated by the control unit 14, which outputs the calculated target cracking ratio to the ammonia metering component 5a in the cracking branch and the ammonia metering component 5b in the direct supply branch. The target hydrogen content is controlled by adjusting the flow ratio between the two components. (Heating ammonia branch flow rate...) The fact that it does not appear in any of the above calculation formulas indicates that the composition calculation of the heating ammonia branch is completely decoupled from that of the main fuel mixture.

[0083] IV. Two-stage cooling structure for the fractured branch.

[0084] In the pyrolysis branch, the waste heat recovery heat exchanger 6 adopts a counter-flow heat exchange structure. The cold-side inlet of the waste heat recovery heat exchanger 6 is connected to the outlet of the ammonia metering component 5a in the pyrolysis branch, the cold-side outlet is connected to the inlet of the pyrolysis unit 7, the hot-side inlet is connected to the outlet of the pyrolysis unit 7, and the hot-side outlet is connected to the inlet of the second-stage cooler 8. The ammonia gas to be pyrolyzed enters the cold side of the waste heat recovery heat exchanger 6. The temperature of the ammonia gas to be pyrolyzed is usually 50℃~100℃. It is heated to 300℃~500℃ by the high-temperature pyrolysis gas on the hot side before entering the pyrolysis unit 7. The high-temperature hydrogen-containing pyrolysis gas at 400℃~800℃ enters the hot side of the waste heat recovery heat exchanger 6 from the outlet of the pyrolysis unit 7. After transferring heat to the cold-side ammonia gas, its own temperature drops to 150℃~350℃.

[0085] The second-stage cooler 8 is located downstream of the hot-side outlet of the waste heat recovery heat exchanger 6 and upstream of the inlet of the mixing buffer tank 11. It is used to further cool the hydrogen-containing cracked gas after its initial cooling by the waste heat recovery heat exchanger 6. The second-stage cooler 8 can be a water-cooled heat exchanger using cooling water as the cooling medium, an air-cooled heat exchanger using ambient air as the cooling medium, a fuel preheating heat exchanger, or other indirect heat exchange methods. Its cooling capacity can be designed to be fixed or adjustable. For an adjustable second-stage cooler 8, the outlet cracked gas temperature is controlled by adjusting the cooling water flow rate, air flow rate, or cooling medium temperature.

[0086] The second-stage cooler 8 primarily addresses the following issues: Under low pyrolysis ratio conditions, the ammonia flow rate entering the cold side of the waste heat recovery heat exchanger 6 is relatively small, and the heat exchange effect of the waste heat recovery heat exchanger 6 alone is limited, making it difficult to ensure that the pyrolysis gas is sufficiently cooled to the allowable temperature range of the mixing buffer tank 11; during the initial stage of system startup or transitional conditions, the outlet temperature of the pyrolysis unit 7 may be too high, requiring additional cooling capacity; electronic sensors are typically installed inside the mixing buffer tank 11, with an upper limit of their allowable operating temperature usually between 80°C and 120°C, requiring it to be ensured that the gas temperature entering the mixing buffer tank 11 is lower than the upper limit of the sensor's allowable operating temperature. Preferably, the second-stage cooler 8 reduces the temperature of the hydrogen-containing pyrolysis gas to the range of 40°C to 120°C, or to below the upper limit of the allowable operating temperature of the sensor inside the mixing buffer tank 11, more preferably to 60°C to 90°C.

[0087] V. Operation of the pyrolyzer heating unit 10.

[0088] The pyrolysis heating device 10 includes a plasma power supply, a plasma-assisted ammonia combustion chamber, a combustion status monitoring component, and a thermal coupling channel. The fuel inlet of the plasma-assisted ammonia combustion chamber is connected to the outlet of the heating ammonia metering component 5c, the oxidant inlet is connected to the outlet of the air metering component 5d, the air is supplied by the air compressor 9, and the ammonia-containing residual gas inlet is connected to the purging discharge end of the inert gas purging unit 13.

[0089] The plasma generation mode in the plasma-assisted ammonia combustion chamber can be selected from at least one of dielectric barrier discharge, sliding arc discharge, microwave plasma, radio frequency plasma, or DC arc plasma. The plasma discharge power can be adjusted according to the heat load requirements of the pyrolyzer 7, typically ranging from 0.1 kW to 50 kW, depending on the scale of the pyrolyzer 7 and the flow rate of the pyrolysis branch. The plasma works by colliding with ammonia and oxygen molecules, generating reactive free radicals and ions such as N, H, NH, NH2, O, and OH, significantly reducing the activation energy of ammonia combustion. This allows ammonia to be ignited at a lower temperature and maintain stable combustion over a wide equivalence ratio range. The control unit 14 precisely controls the heat supply by adjusting the output power of the plasma power supply, based on signals from the pyrolyzer bed temperature sensor and the pyrolyzer outlet pyrolyzer rate sensor, combined with the target pyrolyzer rate.

[0090] The thermal coupling channel is used to transfer the heat released from the plasma-assisted ammonia combustion in the combustion chamber to the pyrolyzer 7. It can be selected from at least one of the following: jacketed heat exchange, flue gas heat exchange, radiative heat exchange, heat-conducting wall heat exchange, or heat pipe heat exchange. Jacketed heat exchange involves high-temperature flue gas or hot fluid flowing through the outer jacket of the pyrolyzer 7; flue gas heat exchange involves high-temperature flue gas flowing directly or indirectly through the outer surface or internal heat exchange tubes of the pyrolyzer 7; radiative heat exchange refers to heating via thermal radiation; heat-conducting wall heat exchange involves direct connection via heat-conducting metal materials; and heat pipe heat exchange utilizes the evaporation-condensation cycle of the working fluid within the heat pipe for heat transfer. In this embodiment, a combination of jacketed heat exchange and radiative heat exchange is used. A high-temperature flue gas jacket is set outside the pyrolyzer 7, and a radiative cavity is set between the combustion chamber and the pyrolyzer 7 to achieve uniform and efficient heating. The control unit 14 adjusts the pyrolyzer bed temperature, pyrolyzer outlet pyrolysis rate, and pyrolysis branch flow rate based on these parameters. Based on signals such as target hydrogen content, adjust plasma discharge power and flow rate of heating ammonia branch. The airflow is also adjusted to maintain the pyrolysis unit 7 within the required pyrolysis temperature window. The combustion exhaust gas from the plasma-assisted ammonia combustion chamber is discharged through a separate exhaust pipe and does not enter the main fuel inlet of the ammonia gas turbine 12, nor does it enter the mixing buffer tank 11.

[0091] VI. Mixing and testing in the mixing buffer tank.

[0092] The mixing buffer tank 11 is a pressure vessel with a certain volume. Its inlet end is connected to the outlet of the cracking branch (i.e., the hydrogen-containing cracked gas cooled by the second-stage cooler 8) and the outlet of the direct supply branch (i.e., the uncracked ammonia gas). Its outlet end is connected to the fuel inlet of the ammonia gas turbine 12. The volume of the mixing buffer tank 11 is determined according to the fuel consumption of the ammonia gas turbine 12, the allowable pressure fluctuation range, and the control response time. In one embodiment, it is designed to accommodate the gas volume of 5 to 30 seconds of fuel consumption by the gas turbine.

[0093] A mixing enhancement structure is provided inside the mixing buffer tank 11 to improve the mixing uniformity of hydrogen-containing cracked gas and directly supplied ammonia. The mixing enhancement structure is selected from at least one of a static mixer, a baffle plate, a porous distributor, or a swirling jet. A static mixer is a static mixing element such as a torsion blade or a spiral plate installed at the pipe or inlet inside the tank; a baffle plate is a baffle plate installed at different angles and positions inside the tank; a porous distributor is a distribution plate with multiple small holes installed at the inlet of the tank; and a swirling jet injects gas into the tank in a tangential or spiral manner to generate a swirling effect. In this embodiment, the mixing buffer tank 11 adopts a combination of top tangential air inlet and bottom porous distributor. The hydrogen-containing cracked gas and the directly supplied ammonia enter from the tangential inlet at the top of the tank to form a swirling premix, and then are further homogenized by the middle porous distributor before being led out from the bottom outlet.

[0094] The mixing buffer tank 11 is also equipped with at least one of the following: a pressure sensor, a temperature sensor, a hydrogen concentration sensor, an ammonia concentration sensor, and a calorific value detection unit. The hydrogen concentration sensor includes self-thermal conductivity, electrochemical, or laser absorption spectroscopy types, and the ammonia concentration sensor includes self-electrochemical, metal oxide semiconductor, or laser absorption spectroscopy types, used to monitor the state and composition of the working fluid inside the tank in real time. The signals collected by the above sensors are transmitted to the control unit 14 in real time as the basis for feedback correction.

[0095] VII. Multi-condition adjustment strategy of the control unit.

[0096] The input signals received by the control unit 14 include at least one of the following types: load command, actual load, and load change rate of the ammonia gas turbine 12; combustion status signals such as combustion chamber pressure pulsation, combustion chamber wall temperature, and flame detection signal; emission signals such as unburned ammonia concentration and nitrogen oxide concentration in the exhaust gas; status signals such as pressure, temperature, hydrogen concentration, ammonia concentration, and calorific value of the mixing buffer tank 11; status signals such as bed temperature and outlet cracking rate of the pyrolyzer 7; and signals such as steam temperature, steam pressure, and feedwater flow rate of the waste heat boiler 15.

[0097] Control unit 14 determines the current operating condition type based on the above signals and executes the corresponding cracking ratio adjustment strategy:

[0098] Start-up condition: The control unit 14 sets a higher target hydrogen content and calculates a higher target cracking ratio accordingly to generate enough hydrogen to improve ignition performance and flame stability. As combustion gradually stabilizes, the target hydrogen content is gradually reduced to the normal operating value.

[0099] Low-load conditions: When the ammonia gas turbine 12 operates at 30% below the rated load, the control unit 14 maintains a high target hydrogen content to ensure flame stability and burnout rate in the combustion chamber.

[0100] Load increase condition: When the control unit 14 detects that the load change rate signal exceeds the preset threshold, it increases the target hydrogen content in advance, i.e., feedforward control, and uses the high reactivity of hydrogen to accelerate the combustion response and improve the combustion stability during the load increase process.

[0101] Steady-state operation: Control unit 14 sets the target hydrogen content according to the needs of system energy efficiency optimization, reduces the cracking ratio R under the premise of ensuring stable combustion, reduces the heat load of cracker 7, and improves the overall energy efficiency of the system.

[0102] Reduced load condition: After detecting a load reduction signal, the control unit 14 gradually reduces the target hydrogen content to avoid excessively high combustion temperature or backfire risk caused by an excessively high proportion of hydrogen in the fuel.

[0103] Unstable combustion conditions: When the control unit 14 receives signals such as the combustion chamber pressure pulsation amplitude exceeding the preset threshold, flame detection signal fluctuation, or increased unburned ammonia concentration in the exhaust gas, it rapidly increases the target hydrogen content and uses the rapid response characteristics of hydrogen to suppress combustion oscillation and unstable combustion. After the unstable signal disappears, it gradually returns to the normal operating value.

[0104] Shutdown condition: After receiving a normal shutdown command, the control unit 14 gradually reduces the cracking ratio R, reduces the heating load of the cracker 7, and coordinates with the load reduction process of the ammonia gas turbine 12. Finally, it closes all ammonia supply valve groups and starts the inert gas purging unit 13 to perform purging and digestion operations.

[0105] Regarding the control mode, the control unit 14 employs a composite control strategy combining feedforward control and feedback control. In feedforward control mode, the control unit 14 adjusts the control based on the target hydrogen content. Calculate the target pyrolysis ratio using the estimated current pyrolysis rate X. The control unit 14 directly outputs control commands to the ammonia metering component 5a in the cracking branch and the ammonia metering component 5b in the direct supply branch. The advantage of feedforward control is its fast response speed, allowing adjustment before changes occur in the composition within the mixing buffer tank 11. In feedback correction mode, the control unit 14 compares the measured values ​​from the hydrogen concentration sensor or ammonia concentration sensor within the mixing buffer tank 11 with the feedforward target value. If the measured deviation exceeds a preset threshold, the cracking ratio R is corrected based on the magnitude and direction of the deviation. When the control unit 14 detects a significant change in the cracking rate X or receives a combustion instability signal, feedback correction is also applied to quickly respond to disturbances.

[0106] VIII. Shutdown, Purge, and Residual Ammonia Disposal. The normal shutdown procedure is as follows: After receiving the normal shutdown command, the control unit 14 first synchronously reduces the target hydrogen content and cracking ratio R according to the load reduction rate command of the ammonia gas turbine 12. When the fuel demand of the ammonia gas turbine 12 drops to the minimum maintenance value or zero value, the ammonia supply valve group of the liquid ammonia metering system 3, the ammonia metering component 5a of the cracking branch, and the ammonia metering component 5b of the direct supply branch is closed, and the main fuel supply to the mixing buffer tank 11 is stopped, and the ammonia gas turbine 12 is shut down. Subsequently, the inert gas purging unit 13 is started, the purging valve group is opened, and inert gas is introduced into the cracking branch, the direct supply branch, and the mixing buffer tank 11 to replace and discharge the residual ammonia-containing gas in the system. The ammonia-containing residual gas discharged from the purging is introduced into the plasma-assisted ammonia combustion chamber of the cracker heating device 10 through the pipeline. In the initial stage of purging, the control unit 14 maintains a certain flow rate of heating ammonia through the heating ammonia metering component 5c. The ammonia gas enters the plasma-assisted ammonia combustion chamber to maintain ignition and stable combustion. As purging proceeds, the residual ammonia-containing gas is gradually displaced and discharged into the plasma-assisted ammonia combustion chamber. When the residual ammonia-containing gas can be stably maintained for combustion, the control unit 14 gradually reduces the flow rate of the heating ammonia branch. Until completely shut down. Control unit 14 continuously monitors the combustion status and exhaust gas composition of the plasma-assisted ammonia combustion chamber. When the residual ammonia concentration is lower than the preset safety threshold, the plasma power supply and related valve groups are shut down, and the purging and disposal operation is completed.

[0107] The emergency shut-off procedure is as follows: When the system detects abnormal operating conditions that endanger safety, such as ammonia leakage, hydrogen leakage, or fire, the control unit 14 triggers the emergency shut-off procedure, immediately closing all emergency shut-off valves of the liquid ammonia metering system 3, the ammonia metering component 5a of the cracking branch, and the ammonia metering component 5b of the direct supply branch, and quickly stopping the supply of fuel to the ammonia gas turbine 12 and the mixing buffer tank 11; simultaneously, the inert gas purging unit 13 is activated to quickly replace the relevant pipelines at the maximum purging flow rate; all ammonia-containing residual gas discharged during purging is introduced into the plasma-assisted ammonia combustion chamber for disposal; after the residual ammonia-containing gas is purged and disposed of, all valve groups and the plasma power supply are shut off. During the above process, the flame arrester, check valve, or isolation valve installed at the ammonia-containing residual gas inlet of the plasma-assisted ammonia combustion chamber can effectively prevent the combustion chamber flame from backflowing into the purging pipeline.

[0108] When the plasma-assisted ammonia combustion chamber shuts down due to a malfunction or its absorption capacity is insufficient to handle the ammonia-containing gas discharged during purging, the control unit 14 switches the ammonia-containing gas to a backup ammonia absorption unit, such as a water spray absorption tower, an acid absorption tower, or an emergency tail gas treatment unit, for disposal.

[0109] It should be noted that at least one of the pyrolysis branch, direct supply branch, and heating ammonia branch is equipped with a check valve to prevent gas backflow, an emergency shut-off valve, a pressure sensor, a temperature sensor, and a pressure relief component. The pressure relief component, such as a safety valve or rupture disc, automatically releases pressure in case of overpressure. The emergency shut-off valve is remotely controlled by the control unit 14 to close quickly. The mixing buffer tank 11 is equipped with a safety pressure relief valve, rupture disc, or safety venting pipeline. When the pressure inside the tank exceeds the design pressure, it automatically releases pressure. An emergency shut-off valve is installed at the outlet to quickly cut off the fuel supply in emergency conditions. A flame arrester, check valve, or isolation valve is installed at the ammonia-containing residual gas inlet of the plasma-assisted ammonia combustion chamber to prevent flame backflow. The system is equipped with ammonia leak detectors and hydrogen leak detectors in key areas such as the liquid ammonia storage tank 1, vaporizer 4, pyrolysis tank 7, mixing buffer tank 11, and ammonia gas turbine 12 fuel system. When the detected leak concentration exceeds the preset alarm threshold, an audible and visual alarm is triggered. When the preset interlock threshold is exceeded, an emergency shut-off and purging and disposal procedure is automatically executed. The system area is equipped with mechanical ventilation and fire extinguishing systems, which are interlocked with the control unit 14. The exhaust duct of the ammonia gas turbine 12 and the independent exhaust duct of the plasma-assisted ammonia combustion chamber are equipped with exhaust gas aftertreatment devices, including a selective catalytic reduction system for removing nitrogen oxides and an ammonia oxidation catalyst for reducing the escape of unburned ammonia.

[0110] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. An ammonia gas turbine fuel supply system based on dynamic adjustment of the cracking ratio, characterized in that, include: A liquid ammonia storage tank (1) is connected to a vaporizer (4) for supplying liquid ammonia to the vaporizer (4); The vaporizer (4) is used to vaporize liquid ammonia into ammonia gas, and the ammonia gas outlet of the vaporizer (4) is provided with a diversion node; The diversion nodes are respectively connected to the pyrolysis branch, the direct supply branch, and the heating ammonia branch; The cracking branch is equipped with a cracker (7), and the outlet of the cracking branch is connected to a mixing buffer tank (11). The cracking branch is used to catalytically crack at least a portion of the ammonia into hydrogen-containing cracked gas and deliver it to the mixing buffer tank (11). The direct supply branch is connected to the mixing buffer tank (11) and is used to directly deliver uncracked ammonia gas to the mixing buffer tank (11). The heating ammonia branch is connected to the pyrolyzer heating device (10), which is thermally coupled to the pyrolyzer (7) to provide the pyrolyzer (7) with the heat required for pyrolysis, and the heating ammonia branch is not connected to the mixing buffer tank (11). The outlet of the mixing buffer tank (11) is connected to the fuel inlet of the ammonia gas turbine (12) for mixing the hydrogen-containing cracked gas with the uncracked ammonia gas and then supplying it to the ammonia gas turbine (12). Inert gas purging unit (13), the purging discharge end of the inert gas purging unit (13) is connected to the pyrolysis heating device (10), and is used to introduce the ammonia-containing residual gas discharged during purging into the pyrolysis heating device (10) for disposal in the case of system shutdown or emergency cut-off. Control unit (14), which is communicatively connected to at least the cracking branch, the direct supply branch and the ammonia gas turbine (12), is configured to dynamically adjust the flow ratio of the cracking branch and the direct supply branch according to the operating conditions of the ammonia gas turbine (12).

2. An ammonia gas turbine fuel supply system based on dynamic adjustment of the cracking ratio according to claim 1, characterized in that It also includes a booster pump (2) and a liquid ammonia metering system (3), wherein the liquid ammonia storage tank (1) is connected to the vaporizer (4) via the booster pump (2) and the liquid ammonia metering system (3).

3. An ammonia gas turbine fuel supply system based on dynamic adjustment of the cracking ratio according to claim 1, characterized in that, The pyrolysis branch is also equipped with a pyrolysis branch ammonia metering component (5a), the direct supply branch is equipped with a direct supply branch ammonia metering component (5b), and the heating ammonia branch is equipped with a heating ammonia metering component (5c). The control unit (14) is communicatively connected to the pyrolysis branch ammonia metering component (5a), the direct supply branch ammonia metering component (5b), and the heating ammonia metering component (5c) respectively, and is used to adjust the ammonia flow rate of each branch respectively.

4. The ammonia gas turbine fuel supply system based on dynamic adjustment of cracking ratio according to claim 1, characterized in that, The molar flow of ammonia entering the cracking branch is denoted by , the molar flow of ammonia entering the direct supply branch is denoted by , the molar flow of ammonia entering the heat supply ammonia branch is denoted by , the cracking ratio is defined as: where is not taken into account in the cracking ratio .

5. The ammonia gas turbine fuel supply system based on dynamic adjustment of cracking ratio according to claim 4, characterized in that, The ammonia cracking rate at the outlet of the cracker (7) is denoted as X. The control unit (14) calculates the theoretical composition of the main fuel mixture in the mixing buffer tank (11) based on R and X, wherein the hydrogen gas integral satisfy: When X reaches the preset complete pyrolysis threshold, the control unit (14) performs feedforward calculations based on X≈1.

6. The ammonia gas turbine fuel supply system based on dynamic adjustment of cracking ratio according to claim 1, characterized in that, It also includes a waste heat boiler (15), the flue gas inlet of which is connected to the exhaust channel of the ammonia gas turbine (12), and the steam outlet of the waste heat boiler (15) is connected to the steam heat exchange channel of the gasifier (4) via a steam regulating valve, for using the exhaust waste heat of the ammonia gas turbine (12) to provide gasification heat to the gasifier (4).

7. The ammonia gas turbine fuel supply system based on dynamic adjustment of cracking ratio according to claim 1, characterized in that, The pyrolysis heating device (10) is a plasma-assisted ammonia combustion chamber, which includes a plasma power supply and a combustion chamber. The heating ammonia branch is connected to the fuel inlet of the combustion chamber, and the combustion chamber is thermally coupled to the pyrolysis unit (7).

8. The ammonia gas turbine fuel supply system based on dynamic adjustment of cracking ratio according to claim 1, characterized in that, The pyrolysis branch is also equipped with a cooling device, which is located downstream of the pyrolyzer (7) and is used to cool the hydrogen-containing pyrolysis gas at the outlet of the pyrolyzer (7) and send it into the mixing buffer tank (11). The cooling device includes a waste heat recovery heat exchanger (6) and a second-stage cooler (8). The cold side of the waste heat recovery heat exchanger (6) is located upstream of the pyrolyzer (7), and the hot side of the waste heat recovery heat exchanger (6) is located downstream of the pyrolyzer (7). The second-stage cooler (8) is located downstream of the hot side outlet of the waste heat recovery heat exchanger (6).

9. A fuel supply system for an ammonia gas turbine based on dynamic adjustment of cracking ratio according to claim 1, characterized in that, The control unit (14) receives the load signal and / or combustion status signal of the ammonia gas turbine (12), determines the target hydrogen content based on the signal, and then calculates the target cracking ratio based on the target hydrogen content. The inert gas purging unit (13) includes a nitrogen source or a carbon dioxide source and a purging valve group. The control unit (14) opens the purging valve group in the case of shutdown or emergency cut-off to replace and discharge the residual ammonia-containing gas in the pyrolysis branch, the direct supply branch and the mixing buffer tank (11) and introduce it into the pyrolysis heating device (10).

10. A fuel supply system for an ammonia gas turbine based on dynamic adjustment of cracking ratio according to claim 1, characterized in that, The mixing buffer tank (11) is provided with a mixing enhancement structure, which is selected from at least one of a static mixer, a baffle plate, a porous distributor and a swirling jet.

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