An on-board ammonia cracking hydrogen production system for ammonia engine and a thermal management method thereof

Abstract

The application relates to an on-vehicle ammonia cracking hydrogen production system of an ammonia engine and a heat management method thereof, which comprises a liquid ammonia storage tank, a liquid ammonia gasification preheating tank, a hydrogen production pipeline, a cracking gas storage pipeline, an ammonia-hydrogen gas channel premixing pipe, an ammonia oxidizer heat production pipeline, an air conveying pipeline and a tail gas conveying pipeline; the heat of the ammonia oxidizer heat production pipeline not only provides heat for ammonia cracking, but also preheats ammonia gas required by ammonia cracking; the ammonia gas required by the ammonia oxidizer heat production pipeline is preheated, and the aftertreatment system is jointly heated in cooperation with the heat of the tail gas of the engine; the molar ratio of the ammonia gas amount and the air amount supply amount is adjusted according to the engine use condition to change the heat release amount of the ammonia oxidizer heat production pipeline, and the most appropriate reaction formula is used for reaction to avoid generation of tail gas pollutants; meanwhile, the heat with the ammonia oxidizer heat production pipeline as the core is distributed and managed.

Description

Technical Field

[0001] This application relates to the field of energy-saving and new energy vehicle technology, and in particular to an on-board ammonia cracking hydrogen production system for an ammonia engine and its thermal management method. Background Technology

[0002] The fuel system of an ammonia fuel compression ignition internal combustion engine is divided into:

[0003] a) Mode: Ammonia + diesel fuel mixture combustion, no hydrogen required.

[0004] b) Mode: Ammonia and hydrogen are mixed and burned. The ammonia source is the on-board liquid ammonia storage tank; the hydrogen source is the on-board hydrogen storage tank and the on-board ammonia cracking hydrogen production system.

[0005] As the reverse reaction of ammonia synthesis, ammonia thermal cracking is an endothermic reaction, and under certain conditions, the conversion rate of ammonia is thermodynamically limited. At 450℃, the thermodynamic equilibrium conversion rate of the ammonia cracking reaction is above 99%. However, based on the reaction kinetics limitations under actual conditions, with the addition of a catalyst, achieving 99% conversion in on-board cracking requires raising the reaction environment temperature to 600℃. Considering heat loss during heat exchange, the temperature of the hot flue gas, serving as the heat source for the ammonia cracking reaction, must be above 650℃.

[0006] In existing technologies, the hot flue gas originates from:

[0007] 1) The exhaust gas temperature is high, but its disadvantage is that the exhaust gas temperature is relatively low, and under most operating conditions the exhaust gas temperature cannot reach 650℃.

[0008] 2) Electric heating has the advantage of simple control, but its disadvantages are low heating power density and high cost.

[0009] 3) The ammonia oxidation reactor generates heat. Its advantage is that the heat power density is high, but its disadvantage is that the heat output is difficult to control, and the reaction produces NOx and N2O, which worsens the exhaust emissions of the whole vehicle.

[0010] Therefore, in view of the above-mentioned shortcomings of hot flue gas sources, a thermal management method for ammonia cracking hydrogen production system of ammonia internal combustion engine is proposed, which can solve the thermal management problem with the ammonia oxidation reactor as the core. Summary of the Invention

[0011] This application provides an on-board ammonia cracking hydrogen production system for an ammonia engine and its thermal management method, in order to solve the problem in related technologies where the heat generation of the ammonia oxidation reactor is difficult to control and the reaction produces NOx and N2O, which worsens the exhaust emissions of the entire vehicle.

[0012] In a first aspect, an on-board ammonia cracking hydrogen production system for an ammonia engine is provided, comprising:

[0013] A liquid ammonia storage tank and a liquid ammonia vaporization preheating tank are connected in sequence; the outlet end of the liquid ammonia vaporization preheating tank is connected to a first ammonia conveying pipe, a second ammonia conveying pipe, a third ammonia conveying pipe and a fourth ammonia conveying pipe;

[0014] The hydrogen generating pipeline has its inlet end connected to the first ammonia supply pipeline and its outlet end connected to the ammonia-hydrogen gas premixing pipeline via a cracked gas storage pipeline; the ammonia-hydrogen gas premixing pipeline is also connected to the second ammonia supply pipeline.

[0015] The ammonia oxidizer heat generation pipeline is connected to the third ammonia supply pipeline and is used to supply heat to the hydrogen generation pipeline; the ammonia oxidizer heat generation pipeline is connected to a first hydroxide hot gas pipeline and a second hydroxide hot gas pipeline; the first hydroxide hot gas pipeline is used to preheat the ammonia in the first ammonia supply pipeline.

[0016] An air delivery pipeline is used to supply oxygen to the ammonia-hydrogen gas premixing pipeline and the ammonia oxidizer heat generation pipeline, and to control the oxygen delivery rate.

[0017] The exhaust gas delivery pipeline includes a first exhaust gas branch and a second exhaust gas branch; the second exhaust gas branch is used to preheat the ammonia gas in the third ammonia delivery pipeline; the first exhaust gas branch is used to connect to the air inlet of the exhaust gas after-treatment system, and the second hydrogen hydroxide gas pipeline and the fourth ammonia delivery pipeline are also used to connect to the air inlet of the exhaust gas after-treatment system.

[0018] In some embodiments, the liquid ammonia vaporization preheating tank includes a primary preheating chamber and a secondary preheating chamber that are connected to each other;

[0019] The primary preheating chamber is connected to the second exhaust gas branch and is also connected to the third ammonia supply pipe and the second ammonia supply pipe.

[0020] The secondary preheating chamber is connected to the first ammonia supply pipe and the fourth ammonia supply pipe, and the first hot hydroxide gas pipeline is connected to the secondary preheating chamber.

[0021] In some embodiments, the hydrogen generation pipeline includes a first shut-off valve, an ammonia cracker, a cracked gas collection pipe, and a second shut-off valve connected in sequence.

[0022] The ammonia oxidizer heat generation pipeline includes a third shut-off valve, an ammonia oxidizer, and an outlet pipe connected in sequence; the ammonia oxidizer and the ammonia cracker exchange heat through a heat exchanger.

[0023] In some embodiments, the pyrolysis gas storage pipeline includes a mixed gas buffer tank, a hydrogen flow meter, and a sixth shut-off valve connected in sequence.

[0024] In some embodiments, the air delivery pipeline includes a first air branch and a second air branch; the first air branch is connected to the ammonia-hydrogen gas premixing pipeline, and the second air branch is connected to the third ammonia delivery pipeline via an air compressor pump.

[0025] In some embodiments, the exhaust gas delivery pipeline further includes a third exhaust gas branch, which is connected to the first air branch via a seventh shut-off valve.

[0026] Secondly, a thermal management method for an on-board ammonia cracking hydrogen production system for an ammonia engine is provided, comprising the following steps:

[0027] Obtain the heating demand type of the on-board ammonia cracking hydrogen production system in order to derive the corresponding control strategy;

[0028] In response to the control strategy, the supply of ammonia and oxygen is controlled.

[0029] In some embodiments, when the heating demand is in the case of engine cold start, the control strategy is as follows:

[0030] According to the gas distribution strategy, the supply of the third ammonia pipeline and the oxygen supply of the air pipeline are controlled so that the heat generated by the ammonia oxidizer heat generation pipeline can meet the heat required for ammonia cracking in the hydrogen generation pipeline, the heat required for the SCR catalyst to start the engine cold start, and the heat required to preheat the ammonia in the first ammonia pipeline.

[0031] Hydrogen generated by the hydrogen generation pipeline is transported to the ammonia-hydrogen premixing pipeline through the cracked gas storage pipeline to ignite the ammonia transported by the second ammonia pipeline and complete the engine ignition; at the same time, the exhaust heat of the second exhaust branch preheats the ammonia in the third ammonia pipeline.

[0032] In some embodiments, when the heating demand is at the engine steady-state operating condition, the control strategy is as follows:

[0033] According to the second gas distribution strategy, the supply of ammonia in the third ammonia supply pipe and the oxygen supply in the air supply pipe are controlled so that the heat generated by the heat generation pipe of the ammonia oxidizer and the heat of the tail gas in the first tail gas branch can jointly heat the tail gas after-treatment system; at the same time, the heat of the tail gas in the second tail gas branch can preheat the ammonia in the third ammonia supply pipe.

[0034] In some embodiments, when the heating demand is under high engine load conditions, the control strategy is as follows:

[0035] According to the gas distribution strategy three, control the supply of the third ammonia pipeline and the oxygen supply of the air pipeline so that the heat generation pipeline of the ammonia oxidizer can meet the heat required for ammonia cracking in the hydrogen generation pipeline, the heat required for preheating the ammonia in the first ammonia pipeline, and the heat required for the second hydrogen hydroxide gas pipeline.

[0036] Hydrogen generated by the hydrogen generation pipeline is transported to the ammonia-hydrogen gas premixing pipeline via the cracked gas storage pipeline to ignite the ammonia transported via the second ammonia pipeline; at the same time, the heat from the tail gas of the second tail gas branch preheats the ammonia in the third ammonia pipeline; the heat from the tail gas of the first tail gas branch and the heat from the second hydrogen hydroxide pipeline jointly heat the tail gas after-treatment system.

[0037] The beneficial effects of the technical solution provided in this application include:

[0038] This application provides an on-board ammonia cracking hydrogen production system for an ammonia engine and its thermal management method. The system comprises a first ammonia supply pipe, a second ammonia supply pipe, a third ammonia supply pipe, and a fourth ammonia supply pipe connected to the outlet of an ammonia vaporization preheating tank; a hydrogen generation pipeline with its inlet connected to the first ammonia supply pipe and its outlet connected to an ammonia-hydrogen gas premixing pipeline via a cracked gas storage pipeline; the ammonia-hydrogen gas premixing pipeline is also connected to the second ammonia supply pipe; an ammonia oxidizer heat generation pipeline is connected to the third ammonia supply pipe and used to supply heat to the hydrogen generation pipeline; and a first hydrogen-oxygen... The system includes a heat transfer gas pipeline and a second heat transfer gas pipeline; the first heat transfer gas pipeline is used to preheat the ammonia gas in the first ammonia transmission pipeline; an air transmission pipeline is used to supply oxygen to the ammonia-hydrogen gas premixing pipeline and the ammonia oxidizer heat generation pipeline, and to control the oxygen supply; a tail gas transmission pipeline includes a first tail gas branch and a second tail gas branch; the second tail gas branch is used to preheat the ammonia gas in the third ammonia transmission pipeline; the first tail gas branch is connected to the inlet of the tail gas after-treatment system, and the inlet of the tail gas after-treatment system is also connected to the second heat transfer gas pipeline and the fourth ammonia transmission pipeline.

[0039] Through the above pipeline design, the heat generated by the ammonia oxidizer's heat generation pipeline not only provides heat for ammonia cracking, but also preheats the ammonia required for ammonia cracking, preheats the ammonia required for the ammonia oxidizer, and provides combined heating to the aftertreatment system in conjunction with the engine's exhaust heat. The above heat management methods are selected for operation according to different engine operating conditions. At the same time, during operation, the molar ratio of ammonia and air supply is adjusted according to different engine operating conditions through the third ammonia supply pipeline and air supply pipeline to determine the heat release, so as to carry out the reaction in the most suitable way and avoid the generation of exhaust pollutant N2O. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of an on-board ammonia cracking hydrogen production system for an ammonia engine provided in an embodiment of this application.

[0042] In the diagram: 1. Liquid ammonia storage tank; 2. Liquid ammonia vaporization preheating tank; 3. First ammonia delivery pipe; 4. Cracking gas storage pipe; 5. Second ammonia delivery pipe; 6. Third ammonia delivery pipe; 7. Fourth ammonia delivery pipe; 8. Hydrogen generation pipe; 9. Ammonia oxidizer heat generation pipe; 10. First hydrogen hydroxide heating pipe; 11. Second hydrogen hydroxide heating pipe; 12. Ammonia-hydrogen premixing pipe; 13. First tail gas branch; 14. Second tail gas branch; 15. First air branch; 16. Second air branch; 17. First shut-off valve; 18. Second shut-off valve; 19. Third shut-off valve; 20. Sixth shut-off valve; 21. Seventh shut-off valve; 22. Fourth shut-off valve; 23. Ammonia cracker; 24. Ammonia oxidizer; 25. Fifth shut-off valve. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] This application provides an on-board ammonia cracking hydrogen production system for an ammonia engine and its thermal management method, in order to solve the problem in related technologies where the heat generation of the ammonia oxidation reactor is difficult to control and the reaction produces NOx and N2O, which worsens the exhaust emissions of the entire vehicle.

[0045] Please see Figure 1 A vehicle-mounted ammonia cracking hydrogen production system for an ammonia engine includes a liquid ammonia storage tank 1, a liquid ammonia vaporization preheating tank 2, a hydrogen generation pipeline 8, a cracked gas storage pipeline 4, an ammonia-hydrogen gas premixing pipeline 12, an ammonia oxidizer heat generation pipeline 9, an air delivery pipeline, and an exhaust gas delivery pipeline.

[0046] The outlet end of the liquid ammonia vaporization preheating tank 2 is connected to the first ammonia conveying pipe 3, the second ammonia conveying pipe 5, the third ammonia conveying pipe 6, and the fourth ammonia conveying pipe 7.

[0047] The inlet of the hydrogen generating pipeline 8 is connected to the first ammonia supply pipeline 3, and the outlet is connected to the ammonia-hydrogen premixing pipeline 12 via the cracked gas storage pipeline 4. The ammonia-hydrogen premixing pipeline 12 is also connected to the second ammonia supply pipeline 5. The second ammonia supply pipeline 5 is connected to the ammonia-hydrogen premixing pipeline 12 via an ammonia flow sensor and an eighth shut-off valve. The ammonia-hydrogen premixing pipeline 12 is connected to the engine's intake manifold.

[0048] The inlet end of the ammonia oxidizer heat generation pipeline 9 is connected to the third ammonia transmission pipeline 6 and is used to supply heat to the hydrogen generation pipeline 8; the outlet end of the ammonia oxidizer heat generation pipeline 9 is connected to the first hydroxide heat gas pipeline 10 and the second hydroxide heat gas pipeline 11; the first hydroxide heat gas pipeline 10 is used to preheat the ammonia gas in the first ammonia transmission pipeline 3.

[0049] An air delivery pipeline is used to supply oxygen to the inlet end of the ammonia-hydrogen gas premixing pipeline 12 and the ammonia oxidizer heat generation pipeline 9, and to control the oxygen delivery rate.

[0050] The exhaust gas delivery pipeline is the engine's exhaust gas pipeline; the exhaust gas delivery pipeline includes a first exhaust gas branch 13 and a second exhaust gas branch 14; the second exhaust gas branch 14 is used to preheat the ammonia gas in the third ammonia delivery pipe 6 to 550°C for use in the hydrogen generation pipeline 8 for cracking; the first exhaust gas branch 13 is used to connect to the air inlet of the exhaust gas aftertreatment system, and the second hydrogen hydroxide heating gas pipeline 11 and the fourth ammonia delivery pipe 7 are also used to connect to the air inlet of the exhaust gas aftertreatment system. The ammonia reducing agent of the exhaust gas aftertreatment system is provided by the vaporization of liquid ammonia output from the fourth ammonia delivery pipe 7, which can replace the urea system function of the original aftertreatment system.

[0051] Through the above pipeline setup, the heat generated by the ammonia oxidizer heat generation pipeline 9 not only provides heat for ammonia cracking but also preheats the ammonia required for cracking to facilitate rapid reaction. Preheating the ammonia required by the ammonia oxidizer heat generation pipeline 9, and coordinating with the engine exhaust heat to provide combined heating for the aftertreatment system, can replace the original DOC unit function of the aftertreatment system. The above heat management method is selected for operation based on different engine operating conditions. Simultaneously, during operation, the third ammonia supply pipeline 6 and the air supply pipeline adjust the molar ratio of ammonia and air supply according to different engine operating conditions to determine the heat released by the ammonia oxidizer heat generation pipeline 9, ensuring the most suitable reaction formula and preventing the generation of exhaust pollutant N2O.

[0052] It should be understood that the above-mentioned chemical reaction formula, which adjusts the molar ratio of ammonia and oxygen air supply to change the operating conditions, is used to avoid the generation of N2O pollutant in the exhaust gas; the reaction formula is as follows:

[0053] Reaction 1: (1) NH3 + 0.75O2 → 0.5N2 + 1.5H2O; ΔH = -2.26 × 10 5 JmoleNH3 reaction formula 2: (2)NH3+O2→0.5N2O+1.5H2O; ΔH=-2.76×10 5 jmoleNH3

[0054] Reaction 3: (3) NH3 + 1.25O2 → NO + 1.5H2O; ΔH = -3.17 × 10 5 jmoleNH3

[0055] Reaction formula 4: (4) NH3 + 1.75O2 → NO2 + 1.5H2O; ΔH = -2.83 × 10 5 jmoleNH3

[0056] That is, by controlling the molar amounts of ammonia and oxygen supplied to the air, the ammonia reaction in the heat generation pipeline 9 of the ammonia oxidizer is prevented from operating in reaction two, thereby avoiding the generation of N2O pollutants in the exhaust gas.

[0057] In some preferred embodiments, the structure of the liquid ammonia vaporization preheating tank 2 is configured as follows:

[0058] The liquid ammonia vaporization preheating tank 2 includes a primary preheating chamber and a secondary preheating chamber that are connected to each other. The primary preheating chamber is connected to the second tail gas branch 14 and to the third ammonia supply pipe 6 and the second ammonia supply pipe 5 to preheat the ammonia gas in it to the ammonia oxidation ignition temperature of 150°C, which is used by the ammonia oxidizer heat generation pipe 9. The secondary preheating chamber is connected to the first ammonia supply pipe 3 and the fourth ammonia supply pipe 7. The first hydroxide hot gas pipe 10 is connected to the secondary preheating chamber and is used to preheat the ammonia gas in the third ammonia supply pipe 6 to a temperature of 550°C.

[0059] In some preferred embodiments, the structures of the hydrogen generating pipeline 8 and the ammonia oxidizer heat generation pipeline 9 are described in detail:

[0060] The hydrogen generation pipeline 8 includes a first shut-off valve 17, an ammonia cracker 23, a cracked gas collection pipe, and a second shut-off valve 18 connected in sequence.

[0061] The ammonia oxidizer heat generation pipeline 9 includes a third shut-off valve 19, an ammonia oxidizer 24, and an outlet pipe connected in sequence; the ammonia oxidizer 24 and the ammonia cracker 23 exchange heat through a heat exchanger.

[0062] The efficiency of heat exchange between ammonia gas in the inner channel of ammonia cracker 23 and ammonia oxidation hot flue gas in the outer channel of ammonia oxidizer 24 is calibrated; the ammonia supply and hydrogen production of ammonia cracker 23 are matched, that is, after the catalyst and heat exchanger of ammonia cracker 23 are selected, the correspondence between the two is calibrated by test.

[0063] Furthermore, the cracked gas storage pipeline 4 includes a mixed gas buffer tank, a hydrogen flow meter, and a sixth shut-off valve 20 connected in sequence; the air delivery pipeline includes a first air branch 15 and a second air branch 16; the first air branch 15 is connected to the ammonia-hydrogen premixed pipeline 12, and the second air branch 16 is connected to the third ammonia delivery pipeline 6 via an air compressor pump; the tail gas delivery pipeline also includes a third tail gas branch, which is connected to the first air branch 15 via a seventh shut-off valve 21. The second hydrogen hydroxide gas pipeline 11 includes a first pipe and a fourth shut-off valve 22; the second tail gas branch 14 includes a second pipe and a fifth shut-off valve 25.

[0064] The above-described ammonia and oxygen air supply molar ratio is controlled by an air compressor pump to control the air supply, and the ammonia supply is controlled by the ammonia injector of the corresponding ammonia delivery pipe; the first ammonia delivery pipe 3, the second ammonia delivery pipe 5, the third ammonia delivery pipe 6 and the fourth ammonia delivery pipe 7 are all equipped with corresponding ammonia injectors.

[0065] This application also proposes a thermal management method for an on-board ammonia cracking hydrogen production system for an ammonia engine, which includes the following steps:

[0066] S01. Obtain the heating demand type of the on-board ammonia cracking hydrogen production system in order to derive the corresponding control strategy;

[0067] S02. In response to the control strategy, the supply of ammonia and oxygen is controlled, as detailed below:

[0068] S020. When the heating demand is in the condition of engine cold start, the control strategy is as follows:

[0069] According to the gas distribution strategy one, the supply of the third ammonia pipeline 6 and the oxygen supply of the air pipeline are controlled so that the heat generated by the ammonia oxidizer heat generation pipeline 9 can meet the heat required for ammonia cracking in the hydrogen generation pipeline 8, the heat required for the SCR catalyst to start the engine cold start, and the heat required to preheat the ammonia in the first ammonia pipeline 3; the gas distribution strategy one is reaction formula one.

[0070] Hydrogen generated by hydrogen generation pipeline 8 is transported to ammonia-hydrogen premixing pipeline 12 via cracked gas storage pipeline 4 to ignite ammonia delivered by second ammonia pipeline 5 and complete engine ignition; at the same time, the exhaust heat of second exhaust branch 14 preheats ammonia in third ammonia pipeline 6.

[0071] S021. When the heating demand is under the steady-state operating condition of the engine, the control strategy is as follows:

[0072] According to the second gas distribution strategy, the supply of ammonia to the third ammonia pipeline 6 and the oxygen supply to the air pipeline are controlled so that the heat generated by the ammonia oxidizer heat generation pipeline 9 and the heat from the tail gas of the first tail gas branch 13 can jointly heat the tail gas after-treatment system; at the same time, the heat from the tail gas of the second tail gas branch 14 can preheat the ammonia in the third ammonia pipeline 6. The second gas distribution strategy is reaction formula four.

[0073] S022. When the heating demand is under high engine load conditions, the control strategy is as follows:

[0074] According to the gas distribution strategy three, the supply of the third ammonia pipeline 6 and the oxygen supply of the air pipeline are controlled so that the heat generated by the ammonia oxidizer heat generation pipeline 9 can meet the heat required for ammonia cracking in the hydrogen generation pipeline 8, the heat required for preheating the ammonia in the first ammonia pipeline 3, and the heat required for the second hydrogen hydroxide heat pipeline 11; the gas distribution strategy three is reaction formula three.

[0075] Hydrogen generated by hydrogen generation pipeline 8 is transported to ammonia-hydrogen premixing pipeline 12 via cracked gas storage pipeline 4 to ignite ammonia transported via second ammonia pipeline 5; at the same time, the heat from the tail gas of second tail gas branch 14 preheats the ammonia in third ammonia pipeline 6; the heat from the tail gas of first tail gas branch 13 and the heat from second hydrogen hydroxide pipeline 11 jointly heat the tail gas after-treatment system, which can replace the DOC unit function of the original after-treatment system.

[0076] Through the above structural design and thermal management methods, the on-board ammonia cracking hydrogen production system of the ammonia engine has the following heat distribution components:

[0077] Part 1: The liquid ammonia vaporization preheating tank 2 absorbs heat from the second tail gas branch 14 and the first hydroxide heat gas pipeline 10.

[0078] Part Two: Gas distribution and heat release of the ammonia oxidizer heat generation pipeline 9; it uses the first ammonia supply pipeline 3 and the second air branch 16 to provide ammonia and oxygen, which react with each other to release heat; the released heat participates in the ammonia cracking of the hydrogen generation pipeline 8, and is transmitted to the tail gas after-treatment system and the liquid ammonia vaporization preheating tank 2.

[0079] Part 3: Hydrogen generation pipeline 8 absorbs heat to crack ammonia and form hydrogen. Hydrogen and ammonia participate in engine ignition and high-load engine operation.

[0080] Part Four: The exhaust gas aftertreatment system absorbs the heat from the first exhaust gas branch 13 and the second hydroxide heat gas pipeline 11.

[0081] In summary, the above methods can solve the thermal management problem centered on the ammonia oxidizer, and also prevent the ammonia reaction in the ammonia oxidizer heat generation pipeline 9 from operating in reaction two, thereby avoiding the generation of N2O pollutants in the exhaust gas.

[0082] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0083] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0084] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0085] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0086] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0087] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the functions specified in one or more boxes. In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory. Memory may include non-persistent memory in computer-readable media, random access memory (RAM), and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0088] Computer-readable media, including both permanent and non-permanent, removable and non-removable media, can store information using any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data.

[0089] Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient media, such as modulated data signals and carrier waves. It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In the absence of further restrictions, an element defined by the phrase "including one..." does not exclude the presence of other identical elements in the process, method, goods or equipment that include the element.

[0090] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An on-board ammonia cracking hydrogen generation system for an ammonia engine, characterized by, It comprises: The liquid ammonia storage tank (1) and the liquid ammonia gasification preheating tank (2) are connected in sequence; the gas outlet end of the liquid ammonia gasification preheating tank (2) is connected with the first ammonia conveying pipe (3), the second ammonia conveying pipe (5), the third ammonia conveying pipe (6) and the fourth ammonia conveying pipe (7); the liquid ammonia gasification preheating tank (2) comprises a first-stage preheating chamber and a second-stage preheating chamber which are connected in communication; the first-stage preheating chamber is communicated with the second tail gas branch (14) and is connected with the third ammonia conveying pipe (6) and the second ammonia conveying pipe (5); the second-stage preheating chamber is connected with the first ammonia conveying pipe (3) and the fourth ammonia conveying pipe (7), and the first hydrogen oxidation heat gas pipe (10) is communicated with the second-stage preheating chamber; The hydrogen generation pipe (8) is connected with the first ammonia conveying pipe (3) at the gas inlet end and is connected with the ammonia hydrogen gas channel premixing pipe (12) through the cracking gas storage pipe (4) at the gas outlet end; the ammonia hydrogen gas channel premixing pipe (12) is also connected with the second ammonia conveying pipe (5); The ammonia oxidation device heat production pipe (9) is connected with the third ammonia conveying pipe (6) and is used for supplying heat to the hydrogen generation pipe (8); the ammonia oxidation device heat production pipe (9) is connected with the first hydrogen oxidation heat gas pipe (10) and the second hydrogen oxidation heat gas pipe (11); the first hydrogen oxidation heat gas pipe (10) is used for preheating the ammonia gas in the first ammonia conveying pipe (3); the hydrogen generation pipe (8) comprises a first stop valve (17), an ammonia cracker (23), a cracking gas collecting pipe and a second stop valve (18) which are connected in sequence; the ammonia oxidation device heat production pipe (9) comprises a third stop valve (19), an ammonia oxidation device (24) and a gas outlet pipe which are connected in sequence; the ammonia oxidation device (24) and the ammonia cracker (23) are heat-exchanged through a heat exchanger; The air conveying pipe is used for providing oxygen to the ammonia hydrogen gas channel premixing pipe (12) and the ammonia oxidation device heat production pipe (9) and controlling the oxygen conveying amount; The tail gas conveying pipe comprises a first tail gas branch (13) and a second tail gas branch (14); the second tail gas branch (14) is used for preheating the ammonia gas in the third ammonia conveying pipe (6); the first tail gas branch (13) is used for being connected with the tail gas post-processing system gas inlet; the second hydrogen oxidation heat gas pipe (11) and the fourth ammonia conveying pipe (7) are also used for being connected with the tail gas post-processing system gas inlet.

2. The on-board ammonia cracking hydrogen production system of the ammonia engine according to claim 1, characterized in that: The cracking gas storage pipe (4) comprises a mixed gas buffer tank, a hydrogen flow meter and a sixth stop valve (20) which are connected in sequence.

3. The on-board ammonia cracking hydrogen production system of the ammonia engine according to claim 1, characterized in that: The air conveying pipe comprises a first air branch (15) and a second air branch (16); the first air branch (15) is communicated with the ammonia hydrogen gas channel premixing pipe (12), and the second air branch (16) is communicated with the third ammonia conveying pipe (6) through an air compression pump.

4. The on-board ammonia cracking hydrogen production system of the ammonia engine according to claim 3, characterized in that: The tail gas conveying pipeline further comprises a third tail gas branch, which is communicated with the first air branch (15) through a seventh stop valve (21).

5. The heat management method of the on-board ammonia cracking hydrogen production system of the ammonia engine according to claim 1, characterized in that: an on-board ammonia cracking hydrogen production system heat supply demand type is obtained to derive a corresponding control strategy; the ammonia and oxygen supply amounts are controlled in response to the control strategy; when the heat supply demand is an engine cold start condition, the control strategy is: the third ammonia supply pipe (6) supply amount and the oxygen supply amount of the air conveying pipeline are controlled according to the gas distribution strategy one, so that the heat production amount of the ammonia oxidizer heat production pipeline (9) meets the heat amount required for ammonia cracking in the hydrogen production pipeline (8), the engine cold start SCR catalyst light-off heat amount, and the heat amount required for preheating the ammonia in the first ammonia supply pipe (3); the hydrogen produced by the hydrogen production pipeline (8) is conveyed to the ammonia hydrogen channel premixing pipe (12) through the cracking gas storage pipeline (4) to ignite the ammonia conveyed by the second ammonia supply pipe (5), and engine ignition is completed; meanwhile, the tail gas heat amount of the second tail gas branch (14) preheats the ammonia in the third ammonia supply pipe (6). when the heat supply demand is an engine steady state condition, the control strategy is: the third ammonia supply pipe (6) supply amount and the oxygen supply amount of the air conveying pipeline are controlled according to the gas distribution strategy two, so that the heat production amount of the ammonia oxidizer heat production pipeline (9) and the tail gas heat amount of the first tail gas branch (13) jointly supply heat to the tail gas aftertreatment system; meanwhile, the tail gas heat amount of the second tail gas branch (14) preheats the ammonia in the third ammonia supply pipe (6).

6. The method of thermal management of an on-board ammonia cracking hydrogen generation system of an ammonia engine according to claim 5, characterized in that, further comprising the following steps: when the heat supply demand is an engine high load condition, the control strategy is: the third ammonia supply pipe (6) supply amount and the oxygen supply amount of the air conveying pipeline are controlled according to the gas distribution strategy three, so that the heat production amount of the ammonia oxidizer heat production pipeline (9) meets the heat amount required for ammonia cracking in the hydrogen production pipeline (8), the heat amount required for preheating the ammonia in the first ammonia supply pipe (3), and the heat amount required for the second hydrogen oxidation hot gas pipeline (11); the hydrogen produced by the hydrogen production pipeline (8) is conveyed to the ammonia hydrogen channel premixing pipe (12) through the cracking gas storage pipeline (4) to ignite the ammonia conveyed by the second ammonia supply pipe (5); meanwhile, the tail gas heat amount of the second tail gas branch (14) preheats the ammonia in the third ammonia supply pipe (6); the tail gas heat amount of the first tail gas branch (13) and the heat amount of the second hydrogen oxidation hot gas pipeline (11) jointly supply heat to the tail gas aftertreatment system.

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