Ammonia fuel waste heat and Kalina cycle coupling utilization system

Abstract

The invention relates to the technical field of ship ammonia fuel power systems, in particular to an ammonia fuel waste heat and Kalina cycle coupling utilization system which comprises an ammonia fuel supply system and a Kalina cycle system, the ammonia fuel supply system comprises a fuel tank and an engine, and low-temperature ammonia fuel in the fuel tank is conveyed to the engine through a supply pipe to do work; the Kalina circulating system comprises a separator, a steam turbine and a generator, ammonia gas in the ammonia fuel supply system is mixed with exhaust gas through an ammonia gas pipe to form an ammonia water solution, and the ammonia water solution sequentially flows through a second heat exchanger and a third heat exchanger through a pipeline and then enters the separator; ammonia steam is separated from the separator to drive the steam turbine to do work and generate electricity through the generator, and exhaust gas generated after the steam turbine does work is mixed with ammonia gas in the ammonia fuel supply system; high-temperature smoke generated after the engine does work is exhausted after heat exchange through the third heat exchanger through the smoke exhaust pipe, and surplus fuel after the engine does work is subjected to heat exchange through the second heat exchanger through the liquid return pipe and then flows back to the fuel tank.

Description

Technical Field

[0001] The present invention relates to the technical field of ammonia fuel power systems for ships, and in particular to a system for coupling waste heat of ammonia fuel with a Kalina cycle. Background Art

[0002] On ammonia-fueled vessels, ammonia fuel is injected directly into the main engine cylinders in liquid form for combustion and power generation. Because liquids are incompressible and prone to overpressure, excess fuel requires a return line and an overpressure relief pipe. Furthermore, ammonia fuel is highly toxic to humans and can form explosive mixtures with air upon leakage, so ammonia capture facilities are required to strictly control leaks and emissions.

[0003] At present, the fuel input pressure requirements given by the general ammonia main engine are 70bar-85bar, and the input temperature requirements are 25℃-45℃. The output pressure and temperature will increase significantly, and they need to be decompressed and cooled before they can be used again, so additional energy is needed to drive them. In addition, after the ammonia fuel main engine is burned, the flue gas is discharged into the atmosphere through the exhaust pipe. The flue gas temperature is generally between 200-450℃, which contains high-grade thermal energy. The liquefaction temperature of ammonia at normal pressure is -33℃, so the fuel tank is mostly set to store liquid ammonia at -33℃, which contains high-grade cold energy. However, the ammonia fuel needs to be heated before entering the main engine, which requires additional heat energy. According to the above characteristics of the ammonia fuel power system, the high-grade thermal energy of the exhaust gas and the high-grade cold energy of the liquid ammonia have not been effectively utilized. Summary of the Invention

[0004] The purpose of the present invention is to provide a system for coupling the waste heat of ammonia fuel with the Kalina cycle to fully utilize high-grade cold and heat resources and solve the problems in the above-mentioned background technology.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is to provide a system for coupling the waste heat of an ammonia fuel with a Kalina cycle, comprising an ammonia fuel supply system and a Kalina cycle system. The ammonia fuel supply system comprises a fuel tank and an engine. The engine is connected to the fuel tank through a liquid supply pipe. A liquid return pipe and an exhaust pipe are connected to the engine. The low-temperature ammonia fuel in the fuel tank is transported to the engine through the supply pipe to perform work. The Kalina cycle system comprises a separator, a steam turbine and a generator. Ammonia in the ammonia fuel supply system is mixed with exhaust gas through an ammonia pipe to form an ammonia solution. The ammonia solution flows through a second heat exchanger and a third heat exchanger in sequence through a pipeline and then enters the separator. Ammonia vapor is separated in the separator to drive the steam turbine to perform work and generate electricity through the generator. The exhaust gas generated after the steam turbine performs work is mixed with the ammonia in the ammonia fuel supply system. The high-temperature flue gas after the engine performs work is discharged through the exhaust pipe after heat exchange through the third heat exchanger. The excess fuel after the engine performs work is returned to the fuel tank through the liquid return pipe after heat exchange through the second heat exchanger.

[0006] Furthermore, the ammonia fuel waste heat and Kalina cycle coupling utilization system also includes an energy storage system, which includes an energy storage bottle group. The energy storage bottle group stores inert gas, and the electrical energy output by the generator is stored in the energy storage bottle group in the form of compressed gas energy storage.

[0007] Furthermore, the ammonia fuel supply system also includes a first compressor and a first heater. The first compressor is arranged on the ammonia pipe, and the first heater is arranged on the liquid supply pipeline. The generator outputs electrical energy to drive the first compressor to compress the ammonia so that its pressure is consistent with the pressure of exhaust steam discharged after the turbine works. The generator outputs electrical energy to drive the first heater to heat the liquid ammonia so that its temperature meets the engine threshold range.

[0008] Furthermore, the Kalina circulation system includes a first booster pump and a second booster pump, which are respectively connected to the energy storage bottle group. By adjusting the output pressure of the gas in the energy storage bottle group, the first booster pump and the second booster pump sequentially pressurize the ammonia solution in the system so that the pressure of the ammonia solution entering the separator reaches the P1 threshold range.

[0009] Furthermore, the Kalina circulation system also includes a first heat exchanger, which is arranged on the pipeline at the bottom of the separator. The low-temperature, high-concentration ammonia solution at the outlet of the first booster pump is heat-exchanged with the high-temperature, low-concentration ammonia solution returning to the mixer at the bottom of the separator in the first heat exchanger, and then the pressure is reduced to the same as the exhaust steam pressure through a throttle valve before entering the mixer.

[0010] Furthermore, the energy storage system also includes a pressure-maintaining tank. The gas released by the energy storage bottle group after pressure regulation enters the pressure-maintaining tank. The pressure-maintaining tank maintains the pressure of the ammonia solution in front of the separator to maintain the pressure entering the separator.

[0011] Furthermore, the energy storage system also includes a second compressor and a fourth heat exchanger. The generator outputs electrical energy to drive the second compressor to work and compress the inert gas into the energy storage bottle group for energy storage; the fourth heat exchanger is arranged on the pipeline of the liquid supply pipe, and the high-temperature gas generated during compression at the outlet of the second compressor flows through the fourth heat exchanger to exchange heat with the ammonia fuel flowing through the liquid supply pipe.

[0012] Furthermore, the return liquid pipe flows through the second heat exchanger to first heat the ammonia solution, and the high-temperature flue gas in the smoke exhaust pipe passes through the third heat exchanger to heat the ammonia solution again, so that the ammonia solution reaches a specified temperature threshold range; part of the flue gas in the smoke exhaust pipe can adjust the flue gas entry amount through the branch pipe and the control valve, thereby controlling the ammonia solution to be heated within the specified temperature threshold range.

[0013] Furthermore, the ammonia fuel supply system also includes an ammonia capture device, which is connected to the liquid supply pipe and the liquid return pipe respectively. The ammonia capture device collects vaporized ammonia and discharges it into the mixer. The exhaust gas generated after the turbine works and the ammonia in the ammonia fuel supply system are both discharged into the mixer for mixing. After the above three are mixed in the mixer, they enter the condenser to liquefy and form an ammonia aqueous solution.

[0014] Furthermore, the ammonia fuel supply system also includes a liquid supply valve group and a liquid return valve group. The ammonia capture device is connected to the liquid supply pipe and the liquid return pipe respectively through the liquid supply valve group and the liquid return valve group. The liquid supply pipe is also connected to a safety valve. The ammonia liquid discharged by the liquid supply valve group and the liquid return valve group and the ammonia liquid discharged by the safety valve in an emergency due to overpressure enter the ammonia capture device for gasification, and the gasified ammonia gas enters the mixer.

[0015] The beneficial effects of the present invention are:

[0016] 1. This design couples the ammonia fuel power system with the Kalina cycle, fully utilizing the high-grade cold energy of the liquid ammonia in the fuel tank, the cold and hot energy during the fuel supply and return processes, and the high-grade thermal energy of the ammonia engine exhaust, achieving step-by-step coupling utilization. Combined with an improved concentration-adjustable Kalina cycle for power generation, this design converts electrical energy into compressed air energy storage for driving the working fluid pump and maintaining pressure. It can also be used for heaters and compressors, fully achieving step-by-step energy utilization and energy conservation and emission reduction.

[0017] 2. In the Kalina cycle, a pneumatic booster pump replaces the electric working fluid pump. Driven by inert gas, it avoids the toxic and flammable hazards associated with leaks from the electric working fluid pump. The pneumatic booster pump uses an energy storage bottle assembly as its air source. The air source pressure supplied to the pneumatic booster pump is adjustable, thereby regulating the booster pump pressure.

[0018] 3. The compressed gas stored in the energy storage bottle group first enters the air bag in the pressure maintaining tank. The air bag can shrink and expand with the pressure change. The outside of the air bag in the pressure maintaining tank is an ammonia solution, which is connected to the separator inlet pipeline through a pipeline. The pressure of the air bag can be adjusted by the energy storage bottle group to adjust the pressure of the ammonia solution in the pressure maintaining tank, thereby maintaining the pressure of the ammonia solution before the separator. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A schematic diagram of the overall structure of a system for coupling waste heat from ammonia fuel with a Kalina cycle, provided in an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the overall structure of the ammonia fuel supply system in the ammonia fuel waste heat and Kalina cycle coupling utilization system provided in an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of the overall structure of the Kalina cycle system in the system for coupling waste heat from ammonia fuel with the Kalina cycle provided in an embodiment of the present invention;

[0023] Figure 4 Schematic diagram of the overall structure of the energy storage system in the ammonia fuel waste heat and Kalina cycle coupling utilization system provided in an embodiment of the present invention.

[0024] Description of reference numerals:

[0025] 100, engine; 101, fuel tank; 102, ammonia capture device; 103, separator; 104, pressure tank; 105, energy storage bottle group; 106, first booster pump; 107, second booster pump; 111, first heat exchanger; 112, second heat exchanger; 113, third heat exchanger; 114, fourth heat exchanger; 118, first heater; 119, condenser; 120, turbine; 121, first compressor; 122, second compressor; 123, Mixer; 124, generator; 131, liquid supply valve group; 132, liquid return valve group; 138, safety valve; 139, throttle valve; 201, liquid supply pipe; 202, liquid return pipe; 203, ammonia pipe; 204, exhaust pipe; 205, steam pipe; 210, electric wire; 301, first working fluid; 302, second working fluid; 303, third working fluid; 304, fourth working fluid; 600, ammonia fuel supply system; 700, Kalina circulation system; 800, energy storage system. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0029] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] Reference Figures 1 to 4 As an embodiment of the present invention, an ammonia fuel waste heat coupled with a Kalina cycle utilization system is provided, which includes an ammonia fuel supply system 600 and a Kalina cycle system 700. The ammonia fuel supply system 600 includes a fuel tank 101 and an engine 100. The engine 100 is connected to the fuel tank 101 through a liquid supply pipe 201. The engine 100 is connected to a liquid return pipe 202 and a smoke exhaust pipe 204. The low-temperature ammonia fuel in the fuel tank 101 is transported to the engine 100 through the supply pipe to perform work; the Kalina cycle system 700 includes a separator 103, a steam turbine 120 and a generator 124. The ammonia in the ammonia fuel supply system 600 is The ammonia pipe 203 mixes with the exhaust gas to form an ammonia solution, which flows through the second heat exchanger 112 and the third heat exchanger 113 in sequence through the pipeline and then enters the separator 103. The ammonia vapor is separated in the separator 103 to drive the steam turbine 120 to work and generate electricity through the generator 124. The exhaust gas generated after the steam turbine 120 works is mixed with the ammonia in the ammonia fuel supply system 600; the high-temperature flue gas after the engine 100 works is discharged through the exhaust pipe 204 after heat exchange in the third heat exchanger 113, and the surplus fuel after the engine 100 works is returned to the fuel tank 101 through the return liquid pipe 202 after heat exchange in the second heat exchanger 112.

[0031] This design couples the ammonia fuel power system with the Kalina cycle, fully utilizing the high-grade cold energy of the liquid ammonia in the fuel tank 101, the cold and hot energy during the fuel supply and return processes, and the high-grade thermal energy of the exhaust gas of the ammonia engine 100, achieving step-by-step coupling utilization and combining it with an improved concentration-adjustable Kalina cycle for power generation.

[0032] Specifically, the ammonia fuel supply system 600 contains the first working fluid 301, which is pure liquid ammonia. In the Kalina cycle system 700, the liquid between the outlet of the condenser 119 and the separator 103 is the second working fluid 302, a medium-to-high concentration ammonia solution. The concentration Z1 of the second working fluid 302 is set between 20% and 90%. The return liquid pipe 202 flows through the second heat exchanger 112 to initially heat the ammonia solution. The high-temperature flue gas in the exhaust pipe 204 then passes through the third heat exchanger 113 to further heat the ammonia solution to a specified temperature threshold. This allows the temperature of the second working fluid 302 in the Kalina cycle system 700 to be adjusted. A branch pipe and a control valve are used to adjust the amount of flue gas entering the third heat exchanger 113 within the exhaust pipe 204, thereby controlling the temperature of the ammonia solution within the specified threshold.

[0033] Furthermore, the ammonia fuel supply system 600 also includes a first compressor 121 and a first heater 118. The first compressor 121 is located on the ammonia pipe 203, and the first heater 118 is located on the liquid supply pipe 201. A generator 124 outputs electricity to drive the first compressor 121 to compress the ammonia, ensuring that its pressure is consistent with the exhaust steam pressure discharged from the turbine 120 after power operation, thereby ensuring the stability and efficiency of the subsequent mixing process. The generator 124 outputs electricity to drive the first heater 118 to heat the liquid ammonia to a temperature within the threshold range of the engine 100, ensuring efficient operation of the engine 100. The generator 124 is connected to the first compressor 121 via an electrical line 210, transmitting electricity to the first compressor 121 and the first heater 118.

[0034] Furthermore, the ammonia fuel waste heat and Kalina cycle coupling utilization system also includes an energy storage system 800, which includes an energy storage bottle group 105. The energy storage bottle group 105 stores inert gas, and the electrical energy output by the generator 124 is stored in the energy storage bottle group 105 in the form of compressed gas energy storage.

[0035] Specifically, the energy storage bottle group 105 contains a third working fluid 303, which can be an inert gas such as nitrogen or helium. The Kalina cycle system 700 includes a first booster pump 106 and a second booster pump 107, each connected to the energy storage bottle group 105. By adjusting the output pressure of the gas from the energy storage bottle group 105, the first booster pump 106 and the second booster pump 107 sequentially pressurize the ammonia solution in the system, so that the pressure of the ammonia solution entering the separator 103 reaches the P1 threshold range. In the Kalina cycle, a pneumatic booster pump replaces the electric working fluid pump and is driven by an inert gas to avoid the toxicity and flammability hazards caused by leakage from the electric working fluid pump. The pneumatic booster pump uses the gas source of the energy storage bottle group 105. The gas source pressure supplied to the pneumatic booster pump is adjustable, thereby adjusting the booster pump pressure. The ammonia solution (second working fluid 302) entering the separator 103 has the same pressure and temperature as the ammonia vapor entering the turbine 120. The pressure P1 is set in the threshold range of 5-50 bar, and the temperature T1 is set in the range of 80°C-220°C. The concentration Z1 of the second working fluid 302 is set in the range of 20%-90%. The operating temperature T2 of the first working fluid 301 in the fuel tank 101 is set in the range of -40°C to 5°C.

[0036] The Kalina circulation system 700 also includes a first heat exchanger 111, which is arranged in the pipeline at the bottom of the separator 103. The low-temperature, high-concentration ammonia solution at the outlet of the first booster pump 106 is heat-exchanged in the first heat exchanger 111 with the high-temperature, low-concentration ammonia solution returning to the mixer 123 at the bottom of the separator 103. The pressure is then reduced to the same level as the exhaust steam pressure through the throttle valve 139 before entering the mixer 123 to ensure the stability and efficiency of the mixing process. After driving turbine 120 to generate electricity, the high-temperature ammonia steam turns into exhaust steam, i.e., low-temperature, low-pressure steam, which enters mixer 123. The low-concentration ammonia solution in the lower portion of separator 103 is depressurized by throttle valve 139 to the same pressure as the exhaust steam from turbine 120 and also enters mixer 123. After mixing, the low-concentration ammonia solution enters condenser 119, where it liquefies the gaseous ammonia and forms a high-concentration ammonia solution. The high-concentration ammonia solution then enters first booster pump 106 for pressurization and is heated by first heat exchanger 111. The low-concentration ammonia solution discharged from separator 103 is cooled by first heat exchanger 111. The high-concentration ammonia solution is heated by heat exchange with the low-concentration ammonia solution in first heat exchanger 111 and then enters second booster pump 107 for pressurization. It is then heated by second heat exchanger 112 and further heated by third heat exchanger 113 before entering separator 103 at high temperature, pressure, and pressure.

[0037] In the Kalina cycle, the outlet from the bottom of separator 103 to mixer 123 is a low-concentration ammonia solution, while the outlet from mixer 123 to the inlet of separator 103 is a high-concentration ammonia solution (second working medium 302). This solution is first heated by refluxed liquid ammonia and then further heated by the exhaust gas from the main engine before entering separator 103. In the upper part of separator 103, the ammonia solution partially evaporates, producing high-temperature ammonia vapor that enters turbine 120, driving turbine 120 and generator 124 for power generation. After some ammonia evaporates within separator 103, the lower part of separator 103 is filled with a low-concentration ammonia solution. According to Raoult's law, the vapor pressure of ammonia in a solution is proportional to its mole fraction in the solution. For low-concentration ammonia solutions, the ammonia partial pressure is low, that is, the mole fraction is low. This results in its partial pressure at the gas-liquid interface being insufficient to overcome the system pressure, making it difficult to evaporate.

[0038] The energy storage system 800 also includes a pressure-maintaining tank 104. The gas released from the energy storage bottle group 105 after pressure regulation enters the pressure-maintaining tank 104. The pressure-maintaining tank 104 maintains the pressure of the ammonia solution before the separator 103 to maintain the pressure inside the separator 103. The compressed gas stored in the energy storage bottle group 105 first enters the airbag inside the pressure-maintaining tank 104. The airbag can contract and expand with pressure changes. The outside of the airbag inside the pressure-maintaining tank 104 contains ammonia solution, which is connected to the inlet pipeline of the separator 103 via a pipeline. The pressure of the airbag can be adjusted by the energy storage bottle group 105 to regulate the pressure of the ammonia solution in the pressure-maintaining tank 104, thereby maintaining the pressure of the ammonia solution before the separator 103.

[0039] The energy storage system 800 further includes a second compressor 122 and a fourth heat exchanger 114. The generator 124 outputs electrical energy to drive the second compressor 122 to compress the inert gas, which enters the energy storage bottle assembly 105 for energy storage. The fourth heat exchanger 114 is located on the liquid supply pipe 201. The high-temperature gas generated by compression at the outlet of the second compressor 122 flows through the fourth heat exchanger 114 and exchanges heat with the ammonia fuel flowing through the liquid supply pipe 201. After the second compressor 122 compresses the gas at high pressure, the gas temperature rises. The gas exchanges heat with the low-temperature ammonia fuel in the ammonia fuel supply pipe 201 through the fourth heat exchanger 114, cooling the gas and heating the ammonia fuel. The cooling and heating processes are carried out through the fourth heat exchanger 114. The generator 124 outputs electrical energy to drive the second compressor 122 to compress the third working fluid 303 (inert gas). The third working fluid 303 enters the energy storage bottle assembly 105 as compressed gas for energy storage.

[0040] Both the first working fluid 301 and the second working fluid 302 are ammonia-containing substances, and their toxicity and flammability and explosive properties are consistent within the equipment and accessory spaces where they are located. This is beneficial for selecting materials for the heat exchanger and related equipment accessories, reducing the cost of coupling utilization, and preventing toxic diffusion and the formation of new flammable and explosive mixture spaces in the other system due to leakage from the heat exchanger and related equipment accessories. This is also beneficial for the layout of related equipment in the two systems, that is, the toxicity and flammability of ammonia will not impose new requirements on the two systems. The third working fluid 303 is an inert gas such as nitrogen and helium, which is not prone to chemical reactions with the first working fluid 301 and the second working fluid 302, thereby providing better compatibility and safety for the system coupling.

[0041] Furthermore, the ammonia fuel supply system 600 also includes an ammonia capture device 102, which is respectively connected to the liquid supply pipe 201 and the liquid return pipe 202. The ammonia capture device 102 collects vaporized ammonia and discharges it into the mixer 123. The exhaust gas generated after the turbine 120 works and the ammonia in the ammonia fuel supply system 600 are discharged into the mixer 123 for mixing. The above three are mixed in the mixer 123 and then enter the condenser 119 to liquefy to form an ammonia aqueous solution.

[0042] Specifically, ammonia fuel is highly toxic to the human body and can form explosive mixtures with air upon leakage. Therefore, an ammonia capture device 102 is required to strictly control leakage and emissions. The ammonia capture device 102 can also fully utilize the leaked and emitted ammonia gas. The ammonia fuel supply system 600 also includes a liquid supply valve assembly 131 and a liquid return valve assembly 132. The ammonia capture device 102 is connected to a liquid supply pipe 201 and a liquid return pipe 202 via the liquid supply valve assembly 131 and the liquid return valve assembly 132, respectively. The liquid supply pipe 201 is also connected to a safety valve 138. The ammonia liquid discharged from the liquid supply valve assembly 131 and the liquid return valve assembly 132, as well as the ammonia liquid discharged by the safety valve 138 due to overpressure emergency, enters the ammonia capture device 102 for vaporization. The vaporized ammonia gas enters the mixer 123. Liquid ammonia released from the liquid supply pipe 201, liquid return pipe 202, and safety valve 138 is vaporized within the ammonia capture device 102 and pressurized by the first compressor 121 to the same pressure as the exhaust steam pressure at the turbine 120 outlet before entering the mixer 123. This ensures the stability and efficiency of the mixing process and thereby increases the ammonia mass fraction in the mixer 123. Furthermore, if the evaporation gas pressure in the fuel tank 101 is too high, it can be pressurized by the first compressor 121 to the same pressure as the exhaust steam before entering the mixer 123 to increase the ammonia mass fraction in the mixer 123. A water injection pipe (not shown) is also provided in the mixer 123 to inject water to dilute the ammonia mass fraction in the mixer 123. This adjustable ammonia mass fraction, combined with the adjustable pressure provided by the two-stage pneumatic booster pump, makes the entire Kalina cycle system 700 an adjustable cycle, enabling flexible and efficient utilization of cooling and heating resources, achieving energy conservation and emission reduction.

[0043] The ammonia fuel starts from the fuel tank 101, is heated by the fourth heat exchanger 114 and / or the condenser 119, and then enters the first heater 118 to be heated. After reaching the specified threshold temperature, it first passes through the liquid supply valve group 131, and then enters the engine 100 to burn and produce work. Some of the excess fuel returns through the return liquid pipe 202. The return liquid pipe 202 is first cooled by the second heat exchange, and then returns to the fuel tank 101 after passing through the return liquid valve group 132.

[0044] During operation, the Kalina cycle system 700 optimizes separation efficiency by regulating pressure, temperature, or working fluid concentration, addressing issues such as insufficient ammonia partial pressure and phase equilibrium limitations, thereby ensuring a high level of thermal efficiency in the Kalina cycle. The second working fluid 302, an aqueous ammonia solution, in the Kalina cycle system 700 features adjustable pressure, concentration, and temperature. The aqueous ammonia solution then enters the separator 103, where it separates into high-temperature, pressurized ammonia vapor, the fourth working fluid 304, which then enters the steam turbine 120 via the steam pipe 205 to drive the turbine 120 to produce power. This creates an adjustable Kalina cycle system 700, achieving efficient utilization of coupled cold and heat energy, driving the generator 124 to generate more electrical energy.

[0045] This design couples the ammonia fuel power system with the Kalina cycle, fully utilizing the high-grade cold energy of the liquid ammonia in the fuel tank 101, the cold and hot energy during the fuel supply and return processes, and the high-grade thermal energy of the exhaust gas of the ammonia engine 100, achieving step-by-step coupled utilization. It also combines this with an improved concentration-adjustable Kalina cycle for power generation and converts the electrical energy into compressed air energy storage for driving the working fluid pump and maintaining pressure. It can also be used for heaters and compressors, fully achieving step-by-step energy utilization and energy conservation and emission reduction.

[0046] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A system for coupling waste heat from ammonia fuel with a Kalina cycle, characterized in that: include: An ammonia fuel supply system (600) includes a fuel tank (101) and an engine (100). The engine (100) is connected to the fuel tank (101) via a liquid supply pipe (201). The engine (100) is connected to a liquid return pipe (202) and a smoke exhaust pipe (204). Low-temperature ammonia fuel in the fuel tank (101) is transported to the engine (100) via the supply pipe to perform work. The Kalina cycle system (700) includes a separator (103), a steam turbine (120) and a generator (124). Ammonia gas in the ammonia fuel supply system (600) is mixed with exhaust gas through an ammonia pipe (203) to form an ammonia solution. The ammonia solution flows through a second heat exchanger (112) and a third heat exchanger (113) in sequence through a pipeline and then enters the separator (103). Ammonia steam is separated in the separator (103) to drive the steam turbine (124). 0) performs work and generates electricity through the generator (124); the exhaust gas generated by the steam turbine (120) after the work is mixed with the ammonia in the ammonia fuel supply system (600); the high-temperature flue gas after the engine (100) performs work is discharged through the exhaust pipe (204) after heat exchange in the third heat exchanger (113); the excess fuel after the engine (100) performs work is returned to the fuel tank (101) through the return pipe (202) after heat exchange in the second heat exchanger (112).

2. The ammonia fuel waste heat and Kalina cycle coupling utilization system according to claim 1, characterized in that: The device also includes an energy storage system (800), which includes an energy storage bottle group (105). The energy storage bottle group (105) stores inert gas, and the electric energy output by the generator (124) is stored in the energy storage bottle group (105) in the form of compressed gas energy storage.

3. The ammonia fuel waste heat and Kalina cycle coupling utilization system according to claim 1, characterized in that: The ammonia fuel supply system (600) further includes a first compressor (121) and a first heater (118). The first compressor (121) is arranged on the ammonia pipe (203), and the first heater (118) is arranged on the liquid supply pipe (201). The generator (124) outputs electrical energy to drive the first compressor (121) to perform work to compress ammonia so that its pressure is consistent with the pressure of exhaust steam discharged after the turbine (120) performs work. The generator (124) outputs electrical energy to drive the first heater (118) to heat the liquid ammonia so that its temperature meets the threshold range of the engine (100).

4. The ammonia fuel waste heat coupled with the Kalina cycle utilization system according to claim 2, characterized in that: The Kalina circulation system (700) includes a first booster pump (106) and a second booster pump (107). The first booster pump (106) and the second booster pump (107) are respectively connected to the energy storage bottle group (105). By adjusting the output pressure of the gas in the energy storage bottle group (105), the first booster pump (106) and the second booster pump (107) sequentially pressurize the ammonia solution in the system, so that the pressure of the ammonia solution entering the separator (103) reaches the P1 threshold range.

5. The ammonia fuel waste heat coupled with the Kalina cycle utilization system according to claim 4, characterized in that: The Kalina circulation system (700) further includes a first heat exchanger (111), which is arranged on a pipeline at the bottom of the separator (103). The low-temperature, high-concentration ammonia solution at the outlet of the first booster pump (106) is heat-exchanged in the first heat exchanger (111) with the high-temperature, low-concentration ammonia solution returning to the mixer (123) from the bottom of the separator (103). The solution is then decompressed to the same pressure as the exhaust steam through a throttle valve (139) and then enters the mixer (123).

6. The ammonia fuel waste heat coupled with Kalina cycle utilization system according to claim 2, characterized in that: The energy storage system (800) further includes a pressure-maintaining tank (104). Gas released from the energy storage bottle group (105) after pressure regulation enters the pressure-maintaining tank (104). The pressure-maintaining tank (104) maintains the pressure of the ammonia solution before the separator (103) to maintain the pressure inside the separator (103).

7. The ammonia fuel waste heat coupled with the Kalina cycle utilization system according to claim 2, characterized in that: The energy storage system (800) further includes a second compressor (122) and a fourth heat exchanger (114). The generator (124) outputs electrical energy to drive the second compressor (122) to perform work to compress the inert gas into the energy storage bottle group (105) for energy storage. The fourth heat exchanger (114) is arranged on the pipeline of the liquid supply pipe (201). The high-temperature gas generated during compression at the outlet of the second compressor (122) flows through the fourth heat exchanger (114) and performs heat exchange with the ammonia fuel flowing through the liquid supply pipe (201).

8. The ammonia fuel waste heat coupled with Kalina cycle utilization system according to claim 2, characterized in that: The return liquid pipe (202) flows through the second heat exchanger (112) to heat the ammonia solution first, and the high-temperature flue gas in the smoke exhaust pipe (204) passes through the third heat exchanger (113) to heat the ammonia solution again, so that the ammonia solution reaches a specified temperature threshold range; the flue gas in the smoke exhaust pipe (204) can be adjusted through the branch pipe and the control valve to adjust the flue gas intake, thereby controlling the ammonia solution to be heated within the specified temperature threshold range.

9. The ammonia fuel waste heat coupled with Kalina cycle utilization system according to claim 1, characterized in that: The ammonia fuel supply system (600) further includes an ammonia capture device (102), which is connected to the liquid supply pipe (201) and the liquid return pipe (202) respectively. The ammonia capture device (102) collects vaporized ammonia and discharges it into the mixer (123). The exhaust gas generated after the steam turbine (120) works and the ammonia in the ammonia fuel supply system (600) are discharged into the mixer (123) for mixing. After the above three are mixed in the mixer (123), they enter the condenser (119) for liquefaction to form an ammonia solution.

10. The ammonia fuel waste heat coupled with the Kalina cycle utilization system according to claim 9, characterized in that: The ammonia fuel supply system (600) further comprises a liquid supply valve group (131) and a liquid return valve group (132). The ammonia capture device (102) is connected to the liquid supply pipe (201) and the liquid return pipe (202) respectively through the liquid supply valve group (131) and the liquid return valve group (132). The liquid supply pipe (201) is also connected to a safety valve (138). The ammonia liquid discharged from the liquid supply valve group (131) and the liquid return valve group (132) and the ammonia liquid discharged by the safety valve (138) in an overpressure emergency enter the ammonia capture device (102) for gasification, and the gasified ammonia gas enters the mixer (123).

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