Multi-heat source ammonia cracking system and vehicle

Abstract

The application relates to a multi-heat-source ammonia cracking system and a vehicle, comprising: an ammonia fuel supply unit, which comprises a liquid ammonia storage tank and a liquid ammonia evaporator connected with the liquid ammonia storage tank to convert liquid ammonia into ammonia gas, and the liquid ammonia evaporator is communicated with an ammonia cracker through a first-stage ammonia gas preheating pipeline; an ammonia fuel heating unit, which comprises an exhaust pipeline in heat exchange with the first-stage ammonia gas preheating pipeline, and an ammonia oxidizer communicated with the first-stage ammonia gas preheating pipeline, and the ammonia oxidizer is in heat exchange with the ammonia cracker. The high-temperature exhaust gas discharged from the exhaust pipeline of the application is used for first-stage preheating of the ammonia gas supplied by the liquid ammonia evaporator, the ammonia gas after first-stage preheating is increased in temperature and then enters the ammonia cracker and the ammonia oxidizer respectively. The ammonia gas entering the ammonia oxidizer generates an exothermic reaction with oxygen, and then exchanges heat with the ammonia cracker. The ammonia gas entering the ammonia cracker is cracked by the ammonia oxidizer to generate hydrogen gas to assist combustion of a hydrogen-ammonia engine, and then the demand of the hydrogen-ammonia engine under different working conditions can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen-ammonia engine, and particularly relates to a multi-heat-source ammonia cracking system and a vehicle. BACKGROUND

[0002] A hydrogen-ammonia engine using ammonia as fuel has been known for a long time. However, the ignition of ammonia fuel in the hydrogen-ammonia engine is poor, and therefore, a combustion improver is required to assist the combustion of ammonia fuel. The combustion of ammonia is not sufficient when the hydrogen-ammonia engine is operated at low load or at high load.

[0003] As the combustion improver, a hydrocarbon fuel or hydrogen can be used. Ammonia is a compound composed of hydrogen atoms and nitrogen atoms, and hydrogen can be produced by chemically decomposing ammonia. Therefore, it is considered that the use of hydrogen produced by decomposing ammonia as the combustion improver is the most ideal system in terms of driving the hydrogen-ammonia engine using only ammonia.

[0004] The reaction of generating hydrogen and nitrogen from ammonia using an ammonia cracking catalyst is an endothermic reaction, and the conversion rate of ammonia is limited by thermodynamics under certain conditions. The thermodynamic equilibrium conversion rate of the ammonia cracking reaction is more than 99% at 450 DEG C.

[0005] However, based on the reaction kinetics in the actual environment, in the case of arranging the catalyst, the reaction environment temperature needs to be increased to 600 DEG C to achieve 99% conversion in vehicle cracking. Considering the heat loss in the heat exchange process, the temperature of the thermal cracking gas as the ammonia cracking reaction environment heat source needs to be more than 650 DEG C.

[0006] At present, the ammonia cracking catalyst is heated by the exhaust gas of the exhaust pipe. Since the temperature of the ammonia cracking catalyst depends on the temperature of the exhaust gas, the combustion efficiency of ammonia in the hydrogen-ammonia engine is poor when the hydrogen-ammonia engine is operated at low load.

[0007] Therefore, there is no high-temperature exhaust gas supplied to the ammonia cracking catalyst, and the reaction of generating hydrogen and nitrogen from ammonia is poor. As a result, hydrogen as a combustion improver for promoting the driving of the hydrogen-ammonia engine is not supplied to the hydrogen-ammonia engine in the low load operation state, and therefore, it takes a long time for the hydrogen-ammonia engine to get out of the low load operation state. SUMMARY

[0008] Embodiments of the present application provide a multi-heat-source ammonia cracking system and a vehicle to solve the problem that the heat source of the ammonia cracking catalyst is single in the related art, and it is difficult to crack hydrogen for combustion in the low load operation state.

[0009] The first aspect of the embodiments of the present application provides a multi-heat-source ammonia cracking system, comprising:

[0010] The ammonia fuel supply unit includes a liquid ammonia storage tank, and a liquid ammonia evaporator connected with the liquid ammonia storage tank to convert liquid ammonia into ammonia gas, and the liquid ammonia evaporator is communicated with an ammonia cracker through a first-stage ammonia gas preheating pipeline;

[0011] The ammonia fuel heating unit includes an exhaust gas pipeline in heat exchange with the first-stage ammonia gas preheating pipeline, and an ammonia oxidizer communicated with the first-stage ammonia gas preheating pipeline, and the ammonia oxidizer is in heat exchange with the ammonia cracker.

[0012] The multi-heat source ammonia cracking system of the present application is provided with a first-stage ammonia gas preheating pipeline in heat exchange with the exhaust gas pipeline between the liquid ammonia evaporator and the ammonia cracker, high-temperature exhaust gas discharged from the exhaust gas pipeline preheats ammonia gas supplied by the liquid ammonia evaporator at a first stage, and ammonia gas preheated at the first stage is respectively introduced into the ammonia cracker and the ammonia oxidizer after the temperature thereof is increased.

[0013] Ammonia gas introduced into the ammonia oxidizer generates an exothermic reaction with oxygen, and by controlling the ratio of oxygen and ammonia gas, the temperature of high-temperature exhaust gas at the outlet of the ammonia oxidizer is stabilized at about 650°C to further exchange heat with the ammonia cracker. Ammonia gas introduced into the ammonia cracker is heated by the ammonia oxidizer to about 600°C to make the ammonia gas crack to generate hydrogen gas to assist combustion of the hydrogen-ammonia engine, and thus the demand of the hydrogen-ammonia engine under different working conditions can be met.

[0014] In some embodiments: the ammonia oxidizer and the ammonia cracker are respectively connected with an electric heater, or an electric heater is provided between the ammonia oxidizer and the ammonia cracker to simultaneously heat the ammonia oxidizer and the ammonia cracker.

[0015] In some embodiments: a first temperature sensor for measuring the temperature of the ammonia cracker is connected to the ammonia cracker, and a second temperature sensor for measuring the temperature of the ammonia oxidizer is connected to the ammonia oxidizer;

[0016] The first temperature sensor and the second temperature sensor are connected with the electric heater through a controller, and when the temperature of the ammonia cracker or the ammonia oxidizer is lower than a set threshold value, the controller controls the electric heater to heat the ammonia cracker and / or the ammonia oxidizer.

[0017] In some embodiments: the inlet end of the ammonia oxidizer is communicated with the first-stage ammonia gas preheating pipeline through an ammonia gas branch pipeline, and a first flow control pump for adjusting the flow of ammonia gas entering the ammonia gas branch pipeline and a second flow control pump for adjusting the flow of oxygen entering the ammonia gas branch pipeline are provided on the ammonia gas branch pipeline.

[0018] In some embodiments: the inlet end of the ammonia cracker is communicated with the first-stage ammonia gas preheating pipeline through a second-stage ammonia gas preheating pipeline, a third flow control pump for adjusting the flow of ammonia gas entering the second-stage ammonia gas preheating pipeline is provided on the second-stage ammonia gas preheating pipeline, and a cracking gas buffer tank is connected to the outlet end of the ammonia cracker.

[0019] In some embodiments: the outlet end of the ammonia oxidizer is connected with a first ammonia cracking heat exchange flow channel plate in heat exchange with the ammonia cracking device, and the end of the first ammonia cracking heat exchange flow channel plate is connected with a second ammonia cracking heat exchange flow channel plate in heat exchange with the secondary ammonia gas preheating pipeline.

[0020] In some embodiments: the ammonia oxidizer, the ammonia cracking device, the first ammonia cracking heat exchange flow channel plate and the second ammonia cracking heat exchange flow channel plate are all in plate structure;

[0021] The ammonia cracking device is connected between the ammonia oxidizer and the first ammonia cracking heat exchange flow channel plate;

[0022] The secondary ammonia gas preheating pipeline is connected between the first ammonia cracking heat exchange flow channel plate and the second ammonia cracking heat exchange flow channel plate.

[0023] In some embodiments: the end of the second ammonia cracking heat exchange flow channel plate is connected with the tail gas pipeline, and the end of the second ammonia cracking heat exchange flow channel plate is located upstream of the heat exchange position of the primary ammonia gas preheating pipeline and the tail gas pipeline on the tail gas pipeline.

[0024] In some embodiments: the tail gas pipeline includes a tail gas heating pipe wrapped around the outer periphery of the primary ammonia gas preheating pipeline, and the primary ammonia gas preheating pipeline is partially located in the mutual gap of the tail gas heating pipe, and the primary ammonia gas preheating pipeline is connected with a fourth flow control pump for adjusting the ammonia gas flow into the hydrogen-ammonia engine.

[0025] The second aspect of the embodiments of the present application provides a vehicle, which comprises the multi-heat-source ammonia cracking system of any one of the above embodiments, and a hydrogen-ammonia engine, wherein the main combustion chamber of the hydrogen-ammonia engine is connected with the primary ammonia gas preheating pipeline, and the pre-combustion chamber of the hydrogen-ammonia engine is connected with the ammonia cracking device.

[0026] The technical scheme provided by the present application has the following beneficial effects:

[0027] The multi-heat-source ammonia cracking system and the vehicle provided by the embodiments of the present application have the following beneficial effects: the multi-heat-source ammonia cracking system provided by the present application is provided with an ammonia fuel supply unit, which includes a liquid ammonia storage tank, a liquid ammonia evaporator connected with the liquid ammonia storage tank to convert liquid ammonia into ammonia gas, and an ammonia cracking device connected with the primary ammonia gas preheating pipeline; the ammonia fuel heating unit includes a tail gas pipeline in heat exchange with the primary ammonia gas preheating pipeline, and an ammonia oxidizer connected with the primary ammonia gas preheating pipeline, and the ammonia oxidizer is in heat exchange with the ammonia cracking device.

[0028] Therefore, the multi-heat source ammonia cracking system of the application is provided with a first ammonia gas preheating pipeline in heat exchange with the tail gas pipeline between the liquid ammonia evaporator and the ammonia cracking device, the high-temperature tail gas discharged from the tail gas pipeline preheats the ammonia gas supplied by the liquid ammonia evaporator in the first stage, and the ammonia gas preheated in the first stage is respectively introduced into the ammonia cracking device and the ammonia oxidizer. The ammonia gas introduced into the ammonia oxidizer generates an exothermic reaction with oxygen, and by controlling the ratio of oxygen and ammonia gas, the temperature of the high-temperature tail gas at the outlet of the ammonia oxidizer is stabilized at about 650°C to further exchange heat with the ammonia cracking device. The ammonia gas introduced into the ammonia cracking device is heated by the ammonia oxidizer to about 600°C to make the ammonia gas crack to generate hydrogen to assist combustion of the hydrogen-ammonia engine, thereby meeting the needs of the hydrogen-ammonia engine under different working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0030] Figure 1 The structure block diagram of the multi-heat source ammonia cracking system of the embodiment of the application.

[0031] Reference signs:

[0032] 11, liquid ammonia storage tank; 12, liquid ammonia evaporator; 13, ammonia cracking device; 14, first-stage ammonia gas preheating pipeline; 15, second-stage ammonia gas preheating pipeline; 16, third flow control pump; 17, fourth flow control pump; 18, first temperature sensor; 19, second temperature sensor;

[0033] 21, tail gas pipeline; 22, ammonia oxidizer; 23, electric heater; 24, ammonia gas branch; 25, first ammonia cracking heat exchange flow channel plate; 26, second ammonia cracking heat exchange flow channel plate; 27, first flow control pump; 28, second flow control pump; 29, tail gas heating pipe. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the application more clear, the technical solutions in the embodiments of the application will be described clearly and completely below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0035] The embodiment of the present application provides a multi-heat-source ammonia cracking system and a vehicle, which can solve the problem that in the related art, a heat source of an ammonia cracking catalyst is single, and it is difficult to crack to generate hydrogen combustion-supporting gas in a low-load operation state.

[0036] Referring to Figure 1 According to the first aspect of the embodiment of the present application, a multi-heat-source ammonia cracking system is provided, comprising:

[0037] The ammonia fuel supply unit comprises a liquid ammonia storage tank 11 and a liquid ammonia evaporator 12 connected with the liquid ammonia storage tank 11 to convert liquid ammonia into ammonia gas, and the liquid ammonia evaporator 12 is communicated with the ammonia cracker 13 through a first-stage ammonia gas preheating pipeline 14. The liquid ammonia storage tank 11 is used for storing liquid ammonia fuel, the liquid ammonia in the liquid ammonia storage tank 11 enters the liquid ammonia evaporator 12, the liquid ammonia evaporator 12 gradually evaporates the entering liquid ammonia into gaseous ammonia gas, and the temperature of the ammonia gas is close to the ambient temperature after heat absorption. The ammonia gas enters the first-stage ammonia gas preheating pipeline 14, exchanges heat with the tail gas pipeline 21, and then enters the ammonia cracker 13 after being heated. The ammonia cracker 13 cracks the ammonia gas at a high temperature to generate hydrogen and nitrogen, and the hydrogen is used for combustion of the ammonia gas in the hydrogen-ammonia engine to provide combustion-supporting gas.

[0038] The ammonia fuel heating unit comprises a tail gas pipeline 21 for heat exchange with the first-stage ammonia gas preheating pipeline 14, and an ammonia oxidizer 22 communicated with the first-stage ammonia gas preheating pipeline 14, and the ammonia oxidizer 22 exchanges heat with the ammonia cracker 13. The ammonia gas in the first-stage ammonia gas preheating pipeline 14 exchanges heat with the tail gas pipeline 21 to be preheated, and then enters the ammonia oxidizer 22. The ammonia oxidizer 22 mixes the ammonia gas with oxygen in the air, the ammonia gas in the ammonia oxidizer 22 is ignited, the proportion of air and ammonia gas is controlled, the high-temperature tail gas temperature at the outlet of the ammonia oxidizer 22 is stabilized at about 650 DEG C, and then the ammonia cracker 13 is heat-exchanged, so that the temperature of the ammonia cracker 13 is maintained at about 600 DEG C, and the ammonia cracker 13 is stabilized to crack the ammonia gas to generate hydrogen.

[0039] The multi-heat-source ammonia cracking system of the embodiment of the present application is provided with the first-stage ammonia gas preheating pipeline 14 for heat exchange with the tail gas pipeline 21 between the liquid ammonia evaporator 12 and the ammonia cracker 13, the high-temperature tail gas discharged from the tail gas pipeline 21 preheats the ammonia gas supplied by the liquid ammonia evaporator 12, the temperature of the ammonia gas after the first-stage preheating is increased, and then the ammonia gas enters the ammonia cracker 13 and the ammonia oxidizer 22. The ammonia gas in the ammonia oxidizer 22 generates an exothermic reaction with oxygen, the proportion of oxygen and ammonia gas is controlled, the high-temperature tail gas temperature at the outlet of the ammonia oxidizer 22 is stabilized at about 650 DEG C, and then the ammonia cracker 13 is heat-exchanged. The ammonia gas in the ammonia cracker 13 is heated by the ammonia oxidizer 22 to about 600 DEG C, so that the ammonia gas is cracked to generate hydrogen to support combustion of the hydrogen-ammonia engine, and then the demand of the hydrogen-ammonia engine under different working conditions can be met.

[0040] In some optional embodiments: referring to Figure 1The application provides a multi-heat source ammonia cracking system, the ammonia oxidizer 22 and the ammonia cracker 13 are respectively connected with an electric heater 23. Alternatively, the electric heater 23 is arranged between the ammonia oxidizer 22 and the ammonia cracker 13 to heat the ammonia oxidizer 22 and the ammonia cracker 13 synchronously. The electric heater 23 is used to heat the ammonia oxidizer 22 or the ammonia cracker 13, and when the temperature of the ammonia oxidizer 22 or the ammonia cracker 13 is lower than a set temperature threshold, the electric heater starts to assist in heating the ammonia oxidizer 22 or the ammonia cracker 13, thereby meeting the start-up combustion temperature of the ammonia oxidizer 22 and the endothermic cracking reaction of the ammonia cracker 13.

[0041] A first temperature sensor 18 for measuring the working temperature of the ammonia cracker 13 is connected to the ammonia cracker 13, and a second temperature sensor 19 for measuring the inlet gas temperature of the ammonia oxidizer 22 is connected to the ammonia oxidizer 22. The first temperature sensor 18 and the second temperature sensor 19 are connected to the electric heater 23 through a controller, and when the temperature of the ammonia cracker 13 or the ammonia oxidizer 22 is lower than a set threshold, the controller controls the electric heater 23 to heat the ammonia cracker 13 or the ammonia oxidizer 22, so that the working temperature of the ammonia cracker 13 or the ammonia oxidizer 22 reaches the set temperature threshold.

[0042] In the application, the electric heater 23 is connected to the ammonia oxidizer 22 and the ammonia cracker 13 respectively, and the electric heater 23 is used to assist in heating the ammonia oxidizer 22 and the ammonia cracker 13. When the hydrogen-ammonia engine is in a cold start state or an idle state, the exhaust gas temperature of the hydrogen-ammonia engine discharged into the exhaust pipe 21 is close to the ambient temperature, and thus the working temperature of the ammonia oxidizer 22 cannot be reached, so the electric heater 23 is needed to heat the ammonia oxidizer 22 to the light-off temperature 180℃ of the catalytic oxidation reaction through electric heating, so as to activate the ammonia oxidizer 22. The first temperature sensor 18 monitors the actual temperature of the ammonia cracker 13 (if the temperature > 600℃, the electric heater 23 is turned off; if the temperature < 600℃, the electric heater 23 is turned on), and the actual temperature of the ammonia cracker 13 is controlled to be around 600℃ by adjusting the power of the electric heater 23.

[0043] When the hydrogen-ammonia engine is in a steady state and a high load working condition, the exhaust gas of the hydrogen-ammonia engine can preheat the ammonia gas in the first-stage ammonia preheating pipeline 14 to obtain first-stage preheated ammonia gas, the second temperature sensor 19 detects that the temperature of the ammonia gas has exceeded 180℃ and enters the ammonia oxidizer 22 to mix with oxygen in the air to directly light off, and the controller controls the electric heater 23 to stop working. Moreover, when the temperature of the ammonia gas has exceeded 180℃ and enters the ammonia cracker 13, the preheated ammonia gas is rapidly heated to about 650℃ by the heating action of the ammonia oxidizer 22 to produce hydrogen gas by high-temperature cracking, and the electric heater 23 does not need to work.

[0044] In some optional embodiments:Figure 1 The application provides a multi-heat-source ammonia cracking system, and the inlet end of an ammonia oxidizer 22 of the multi-heat-source ammonia cracking system is communicated with a first-stage ammonia gas preheating pipeline 14 through an ammonia gas branch 24, the ammonia gas branch 24 is provided with a first flow control pump 27 for adjusting the flow of entering ammonia gas and a second flow control pump 28 for adjusting the flow of entering oxygen. The ammonia gas branch 24 is used for supplying ammonia gas to the ammonia oxidizer 22, the first flow control pump 27 is used for controlling the flow of ammonia gas flowing into the ammonia gas branch 24 from the first-stage ammonia gas preheating pipeline 14, and the second flow control pump 28 is used for controlling the flow of air flowing into the ammonia gas branch 24, so as to adjust the mixing ratio of ammonia gas and oxygen in the ammonia oxidizer 22. The mixing ratio of ammonia gas and oxygen is adjusted through the first flow control pump 27 and the second flow control pump 28, so that the outlet high-temperature tail gas temperature of the ammonia oxidizer 22 is stably controlled to be about 650 DEG C.

[0045] The inlet end of the ammonia cracker 13 is communicated with the first-stage ammonia gas preheating pipeline 14 through a second-stage ammonia gas preheating pipeline 15, the second-stage ammonia gas preheating pipeline 15 is provided with a third flow control pump 16 for adjusting the flow of entering ammonia gas, and the outlet end of the ammonia cracker 13 is connected with a cracking gas buffer tank (not shown in the figure). Hydrogen generated by the ammonia cracker 13 is continuously stored in the cracking gas buffer tank, and after a certain amount of storage, the hydrogen ammonia engine is ignited for cold start. The third flow control pump 16 is used for controlling the flow of ammonia gas flowing into the ammonia cracker 13, so as to provide a set demand amount of hydrogen for the hydrogen ammonia engine. The first-stage ammonia gas preheating pipeline 14 supplies ammonia gas, and the ammonia gas is divided into three parts. The first part is used for supplying the hydrogen ammonia engine and serving as fuel of the hydrogen ammonia engine, the second part is supplied to the ammonia oxidizer 22 through the ammonia gas branch 24 and serves as fuel of the ammonia oxidizer 22, and the third part is supplied to the ammonia cracker 13 through the second-stage ammonia gas preheating pipeline 15 and serves as raw material for generating hydrogen in the high-temperature cracking reaction of the ammonia cracker 13.

[0046] In some optional embodiments, referring to Figure 1 The application provides a multi-heat-source ammonia cracking system, and the outlet end of an ammonia oxidizer 22 of the multi-heat-source ammonia cracking system is connected with a first ammonia cracking heat exchange flow channel plate 25 for heat exchange with an ammonia cracker 13, and the end of the first ammonia cracking heat exchange flow channel plate 25 is communicated with a second ammonia cracking heat exchange flow channel plate 26 for heat exchange with a second-stage ammonia gas preheating pipeline 15. The first ammonia cracking heat exchange flow channel plate 25 is used for heat exchanging the 650 DEG C high-temperature tail gas at the outlet of the ammonia oxidizer 22 with the ammonia cracker 13, so that the temperature of the ammonia cracker 13 is maintained at about 600 DEG C. The tail gas flowing out of the first ammonia cracking heat exchange flow channel plate 25 enters the second ammonia cracking heat exchange flow channel plate 26, the second ammonia cracking heat exchange flow channel plate 26 is heat exchanged with the second-stage ammonia gas preheating pipeline 15, and the second-stage ammonia gas preheating pipeline 15 is preheated.

[0047] The ammonia oxidizer 22, the ammonia cracker 13, the first ammonia cracking heat exchange flow channel plate 25 and the second ammonia cracking heat exchange flow channel plate 26 are all plate structures. The ammonia cracker 13 is connected between the ammonia oxidizer 22 and the first ammonia cracking heat exchange flow channel plate 25; the secondary ammonia gas preheating pipeline 15 is connected between the first ammonia cracking heat exchange flow channel plate 25 and the second ammonia cracking heat exchange flow channel plate 26. The second ammonia cracking heat exchange flow channel plate 26 can heat the ammonia gas in the secondary ammonia gas preheating pipeline 15 to about 450 DEG C. The ammonia oxidizer 22, the ammonia cracker 13, the first ammonia cracking heat exchange flow channel plate 25 and the second ammonia cracking heat exchange flow channel plate 26 are stacked with each other, the structure is more compact, the volume is small, the temperature is not easy to flow out, the heat exchange efficiency is high, the heat exchange structure is simple, the influence of the external environment temperature is small, and the service reliability is high.

[0048] In some optional embodiments, referring to Figure 1 The second ammonia cracking heat exchange flow channel plate 26 of the multi-heat-source ammonia cracking system is in communication with the tail gas pipeline 21, and the end of the second ammonia cracking heat exchange flow channel plate 26 is located upstream of the heat exchange position of the primary ammonia gas preheating pipeline 14 and the tail gas pipeline 21 on the tail gas pipeline 21. After the second ammonia cracking heat exchange flow channel plate 26 exchanges heat with the secondary ammonia gas preheating pipeline 15, the temperature of the tail gas in the second ammonia cracking heat exchange flow channel plate 26 can still be maintained at 450 DEG C. The exhaust heat of the tail gas discharged from the second ammonia cracking heat exchange flow channel plate 26 mixes with the tail gas in the tail gas pipeline 21, and can again preheat the primary ammonia gas preheating pipeline 14 located downstream of the tail gas pipeline 21, so that the temperature of the ammonia gas in the primary ammonia gas preheating pipeline 14 can be maintained at about 250 DEG C.

[0049] In some optional embodiments, referring to Figure 1 The multi-heat-source ammonia cracking system provided by the embodiment of the application comprises a tail gas pipeline 21, wherein the tail gas pipeline 21 comprises a tail gas heating pipe 29 wrapped around the outer periphery of the primary ammonia gas preheating pipeline 14, the primary ammonia gas preheating pipeline 14 is partially located in the tail gas heating pipe 29 and is in clearance fit with the tail gas heating pipe 29, and the primary ammonia gas preheating pipeline 14 is connected with a fourth flow control pump 17 for adjusting the flow of ammonia gas entering the hydrogen-ammonia engine. The tail gas heating pipe 29 is a section of the tail gas pipeline 21 for discharging tail gas, the inner diameter of the tail gas heating pipe 29 is greater than the outer diameter of the primary ammonia gas preheating pipeline 14, so that the primary ammonia gas preheating pipeline 14 can be preheated by high-temperature tail gas (with a temperature of 200-400 DEG C) located in the tail gas heating pipe 29, and the heat exchange efficiency of the primary ammonia gas preheating pipeline 14 and the tail gas pipeline 21 is improved.

[0050] In some optional embodiments, referring to Figure 1As shown, the second aspect of the embodiment of the present application provides a vehicle, which comprises the multi-heat source ammonia cracking system of any of the above embodiments, and a hydrogen-ammonia engine, a main combustion chamber of the hydrogen-ammonia engine is communicated with the first ammonia gas preheating pipeline 14, and a pre-combustion chamber of the hydrogen-ammonia engine is communicated with the ammonia cracker 13. The hydrogen gas generated by high-temperature cracking of the ammonia cracker 13 enters the pre-combustion chamber of the hydrogen-ammonia engine, and after the hydrogen gas is ignited in the pre-combustion chamber, a jet flame is generated to quickly ignite the ammonia gas in the main combustion chamber of the hydrogen-ammonia engine, and the ammonia gas is ignited to provide power for the hydrogen-ammonia engine.

[0051] Working principle

[0052] The embodiment of the present application provides a multi-heat source ammonia cracking system and a vehicle. The multi-heat source ammonia cracking system of the present application is provided with an ammonia fuel supply unit, the ammonia fuel supply unit comprises a liquid ammonia storage tank 11 and a liquid ammonia evaporator 12 connected with the liquid ammonia storage tank 11 to convert liquid ammonia into ammonia gas, the liquid ammonia evaporator 12 is communicated with the ammonia cracker 13 through the first ammonia gas preheating pipeline 14; an ammonia fuel heating unit, the ammonia fuel heating unit comprises a tail gas pipeline 21 in heat exchange with the first ammonia gas preheating pipeline 14, and an ammonia oxidizer 22 communicated with the first ammonia gas preheating pipeline 14, the ammonia oxidizer 22 is in heat exchange with the ammonia cracker 13.

[0053] Therefore, the multi-heat source ammonia cracking system of the present application is provided with the first ammonia gas preheating pipeline 14 in heat exchange with the tail gas pipeline 21 between the liquid ammonia evaporator 12 and the ammonia cracker 13, the high-temperature tail gas discharged from the tail gas pipeline 21 preheats the ammonia gas supplied by the liquid ammonia evaporator 12, and the ammonia gas preheated by the first preheating enters the ammonia cracker 13 and the ammonia oxidizer 22 respectively. The ammonia gas in the ammonia oxidizer 22 generates an exothermic reaction with oxygen, and by controlling the ratio of oxygen and ammonia, the high-temperature tail gas temperature at the outlet of the ammonia oxidizer 22 is stabilized at about 650℃, and then the high-temperature tail gas is in heat exchange with the ammonia cracker 13.

[0054] The ammonia gas in the ammonia cracker 13 is heated by the ammonia oxidizer 22 to about 600℃ to make the ammonia gas crack to generate hydrogen gas to assist combustion of the hydrogen-ammonia engine, thereby meeting the needs of the hydrogen-ammonia engine under different working conditions.

[0055] In the description of the present application, it should be noted that the terms "upper", "lower", and the like are used for indicating the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. Unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0056] It should be noted that in the present application, relational terms such as "first" and "second", and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed, or other elements inherent in such a process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of other identical elements in the process, method, article or apparatus including the element.

[0057] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A multi-heat source ammonia cracking system, characterized in that, The application relates to a multi-heat-source ammonia cracking system, which comprises the following parts: an ammonia fuel supply unit, which comprises a liquid ammonia storage tank (11) and a liquid ammonia evaporator (12) connected with the liquid ammonia storage tank (11) and used for converting liquid ammonia into ammonia gas, and the liquid ammonia evaporator (12) is communicated with an ammonia cracker (13) through a primary ammonia gas preheating pipeline (14); an ammonia fuel heating unit, which comprises a tail gas pipeline (21) used for heat exchange with the primary ammonia gas preheating pipeline (14) and an ammonia oxidizer (22) communicated with the primary ammonia gas preheating pipeline (14) and used for heat exchange with the ammonia cracker (13); an inlet end of the ammonia cracker (13) is communicated with the primary ammonia gas preheating pipeline (14) through a secondary ammonia gas preheating pipeline (15), a third flow control pump (16) for adjusting the flow of entering ammonia gas is arranged on the secondary ammonia gas preheating pipeline (15), and a cracking gas buffer tank is connected with an outlet end of the ammonia cracker (13); an outlet end of the ammonia oxidizer (22) is connected with a first ammonia cracking heat exchange flow channel plate (25) used for heat exchange with the ammonia cracker (13), and a tail end of the first ammonia cracking heat exchange flow channel plate (25) is communicated with a second ammonia cracking heat exchange flow channel plate (26) used for heat exchange with the secondary ammonia gas preheating pipeline (15); the ammonia oxidizer (22), the ammonia cracker (13), the first ammonia cracking heat exchange flow channel plate (25) and the second ammonia cracking heat exchange flow channel plate (26) are all plate structures; the ammonia cracker (13) is connected between the ammonia oxidizer (22) and the first ammonia cracking heat exchange flow channel plate (25); the secondary ammonia gas preheating pipeline (15) is connected between the first ammonia cracking heat exchange flow channel plate (25) and the second ammonia cracking heat exchange flow channel plate (26); a tail end of the second ammonia cracking heat exchange flow channel plate (26) is communicated with the tail gas pipeline (21), and the tail end of the second ammonia cracking heat exchange flow channel plate (26) is located upstream of a heat exchange position of the primary ammonia gas preheating pipeline (14) and the tail gas pipeline (21) on the tail gas pipeline (21).

2. The multi-heat-source ammonia cracking system according to claim 1, wherein: the ammonia oxidizer (22) and the ammonia cracker (13) are respectively connected with an electric heater (23), or an electric heater (23) is arranged between the ammonia oxidizer (22) and the ammonia cracker (13) and used for heating the ammonia oxidizer (22) and the ammonia cracker (13) synchronously.

3. The multi-heat-source ammonia cracking system according to claim 2, wherein: a first temperature sensor (18) for measuring the temperature of the ammonia cracker (13) is connected with the ammonia cracker (13), and a second temperature sensor (19) for measuring the temperature of the ammonia oxidizer (22) is connected with the ammonia oxidizer (22). The first temperature sensor (18) and the second temperature sensor (19) are both connected with the electric heater (23) through a controller, and when the temperature of the ammonia cracker (13) or the ammonia oxidation device (22) is lower than a set threshold, the controller controls the electric heater (23) to heat the ammonia cracker (13) and / or the ammonia oxidation device (22).

4. The multi-heat source ammonia cracking system of claim 1, wherein: The inlet end of the ammonia oxidation device (22) is communicated with the primary ammonia preheating pipeline (14) through an ammonia branch pipeline (24), and the ammonia branch pipeline (24) is provided with a first flow control pump (27) for adjusting the flow of entering ammonia and a second flow control pump (28) for adjusting the flow of entering oxygen.

5. The multi-heat source ammonia cracking system of claim 1, wherein: The tail gas pipeline (21) comprises a tail gas heating pipe (29) wrapped around the outer periphery of the primary ammonia preheating pipeline (14), and the primary ammonia preheating pipeline (14) is partially located in the tail gas heating pipe (29) in a gap fit, and the primary ammonia preheating pipeline (14) is connected with a fourth flow control pump (17) for adjusting the flow of ammonia entering the hydrogen-ammonia engine.

6. A vehicle characterized by comprising: The vehicle comprises the multi-heat source ammonia cracking system of any one of claims 1 to 5, and a hydrogen-ammonia engine, and the main combustion chamber of the hydrogen-ammonia engine is communicated with the primary ammonia preheating pipeline (14), and the pre-combustion chamber of the hydrogen-ammonia engine is communicated with the ammonia cracker (13).

Images