A multi-stage energy utilization system for recycling hydrogen internal combustion engine waste heat and hydrogen storage pressure energy

Abstract

The application discloses a multistage energy utilization system for recycling hydrogen internal combustion engine waste heat and hydrogen storage pressure energy, which comprises a hydrogen storage tank, an electromagnetic valve, a hydrogen heater, a hydrogen expander, a refrigerator, a hydrogen internal combustion engine and a Rankine cycle waste heat recovery system; the outlet of the hydrogen storage tank is communicated with the inlet of the electromagnetic valve; the outlet of the electromagnetic valve is communicated with the cold end inlet of the hydrogen heater; the cold end outlet of the hydrogen heater is communicated with the inlet of the hydrogen expander; the outlet of the hydrogen expander is communicated with the cold end inlet of the refrigerator; the cold end outlet of the refrigerator is communicated with the fuel inlet of the hydrogen internal combustion engine; the flue gas outlet of the hydrogen internal combustion engine is communicated with one end of a first branch and one end of a second branch respectively; the other end of the first branch is communicated with the flue gas side inlet of the Rankine cycle waste heat recovery system; the other end of the second branch is communicated with the hot end inlet of the hydrogen heater; the application can fully recycle the waste heat energy of the hydrogen internal combustion engine and the hydrogen pressure energy of the hydrogen storage tank, and realizes multistage and efficient utilization of energy.

Description

Technical Field

[0001] This invention relates to the field of thermal cycle system technology, and in particular to a multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and storing hydrogen pressure energy. Background Technology

[0002] Currently, hydrogen energy is considered the most promising clean energy source. Hydrogen internal combustion engines are receiving significant attention due to their mature industrial base and advantages such as high power density and high efficiency.

[0003] However, approximately 50% of the energy in a hydrogen internal combustion engine is carried away by flue gas, cylinder liner water, etc., resulting in a significant amount of energy waste. Furthermore, the hydrogen in the storage tank has very high pressure, and the hydrogen often needs to be depressurized before entering the engine cylinders, further wasting hydrogen pressure energy.

[0004] Therefore, how to effectively recover and utilize the waste heat and pressure energy generated during the operation of hydrogen internal combustion engines is a key technical problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to address the technical deficiencies of existing technologies by providing a multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and storing hydrogen pressure energy.

[0006] Therefore, the present invention provides a multi-stage energy utilization system for recovering waste heat from a hydrogen internal combustion engine and hydrogen storage pressure energy, which includes a hydrogen storage tank, a solenoid valve, a hydrogen heater, a hydrogen expander, a refrigerator, a hydrogen internal combustion engine, and a Rankine cycle waste heat recovery system.

[0007] The outlet of the hydrogen storage tank is connected to the inlet of the solenoid valve.

[0008] The outlet of the solenoid valve is connected to the cold end inlet of the hydrogen heater;

[0009] The cold end outlet of the hydrogen heater is connected to the inlet of the hydrogen expander;

[0010] The outlet of the hydrogen expander is connected to the cold end inlet of the refrigerator;

[0011] The cold end outlet of the refrigerator is connected to the fuel inlet of the hydrogen internal combustion engine;

[0012] The exhaust outlet of the hydrogen internal combustion engine is connected to one end of the first branch and one end of the second branch, respectively.

[0013] The other end of the first branch is connected to the flue gas side inlet of the Rankine cycle waste heat recovery system.

[0014] The other end of the second branch is connected to the hot end inlet of the hydrogen heater.

[0015] The Rankine cycle waste heat recovery system is used to recover the heat of the flue gas transported in the first branch.

[0016] A hydrogen heater is used to recover the heat from the flue gas transported in the second branch.

[0017] Preferably, the hot end outlet of the hydrogen heater is connected to the external atmospheric environment;

[0018] The hot end inlet of the refrigerator is connected to the refrigerant piping;

[0019] The hot end outlet of the refrigeration unit is connected to the external location where cooling energy is required.

[0020] Preferably, the Rankine cycle waste heat recovery system includes a flue gas evaporator, a waste heat recovery expander, a condenser, and a working fluid pump;

[0021] The working fluid outlet of the flue gas evaporator is connected to the working fluid inlet of the expander.

[0022] The working fluid outlet of the expander for waste heat recovery is connected to the working fluid inlet of the condenser;

[0023] The working fluid outlet of the condenser is connected to the working fluid inlet of the working fluid pump;

[0024] The working fluid outlet of the working fluid pump is connected to the working fluid inlet of the flue gas evaporator;

[0025] The other end of the first branch is connected to the flue gas side inlet of the flue gas evaporator of the Rankine cycle waste heat recovery system.

[0026] Preferably, the flue gas outlet of the flue gas evaporator is connected to the external atmospheric environment;

[0027] The cold end inlet of the condenser is connected to an external device or location that provides cooling water or cooling air.

[0028] The cold end outlet of the condenser is connected to the external cooling water return pipeline or the external atmospheric environment.

[0029] Preferably, the hydrogen expander is coaxial with the expander used for waste heat recovery in the Rankine cycle waste heat recovery system.

[0030] Preferably, the power output shaft of the hydrogen expander and the power output shaft of the expander used for waste heat recovery in the Rankine cycle waste heat recovery system are coaxial through a coupling.

[0031] Preferably, the following operating modes are included:

[0032] When the hydrogen internal combustion engine is running normally, the exhaust gas from the hydrogen internal combustion engine is divided into two branches. The exhaust gas from the first branch is fed into the flue gas evaporator in the Rankine cycle waste heat recovery system to heat the working fluid. The heated working fluid pushes the waste heat recovery expander to expand and do work. Then it is cooled by the condenser. The cooled working fluid is compressed by the working fluid pump and returned to the flue gas evaporator to be reheated, thus completing the internal cycle of the Rankine cycle waste heat recovery system.

[0033] The flue gas from the second branch is used in the hydrogen heater to heat the high-pressure hydrogen flowing in from the hydrogen storage tank through the solenoid valve, thereby forming high-temperature and high-pressure hydrogen. The high-temperature and high-pressure hydrogen is then expanded by the hydrogen expander to do work, and outputs power simultaneously with the waste heat recovery expander in the Rankine cycle waste heat recovery system. After the hydrogen expander expands and does work, the pressure and temperature of the hydrogen are reduced, which can be used to further provide cooling in the refrigerator. The hydrogen output from the cold end outlet of the refrigerator is used to enter the hydrogen internal combustion engine for combustion.

[0034] As can be seen from the technical solution provided by the present invention above, compared with the prior art, the present invention provides a multi-stage energy utilization system for recovering waste heat and hydrogen pressure energy of hydrogen internal combustion engines. Its scientific design enables multi-stage effective recovery and utilization of waste heat energy and pressure energy generated during the operation of hydrogen internal combustion engines, fully recovering and utilizing the waste heat energy of hydrogen internal combustion engines and the hydrogen pressure energy of hydrogen storage tanks, realizing multi-stage efficient utilization of energy, which has significant practical significance.

[0035] Based on the multi-stage energy utilization system provided by this invention, a portion of the waste heat from the hydrogen internal combustion engine is utilized by the Rankine cycle waste heat recovery system to generate useful work, while another portion of the waste heat is used to heat the high-pressure hydrogen at the outlet of the hydrogen storage tank to obtain high-temperature and high-pressure hydrogen, which can then expand and perform work. The low-temperature and low-pressure hydrogen formed after expansion and work can further release its cooling capacity in the refrigerator as needed, and then enter the hydrogen internal combustion engine for combustion. Therefore, the waste heat energy of the hydrogen internal combustion engine and the hydrogen pressure energy of the hydrogen storage tank are fully utilized. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a multi-stage energy utilization system for recovering waste heat from a hydrogen internal combustion engine and storing hydrogen pressure energy, provided by the present invention. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention 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 the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] See Figure 1 The present invention provides a multi-stage energy utilization system for recovering waste heat from a hydrogen internal combustion engine and storing hydrogen pressure energy, including a hydrogen storage tank 1, a solenoid valve 2, a hydrogen heater 3, a hydrogen expander 4, a refrigerator 5, a hydrogen internal combustion engine 6, and a Rankine cycle waste heat recovery system 7.

[0042] The outlet of hydrogen storage tank 1 is connected to the inlet of solenoid valve 2.

[0043] The outlet of solenoid valve 2 is connected to the cold end inlet of hydrogen heater 3;

[0044] The cold end outlet of the hydrogen heater 3 is connected to the inlet of the hydrogen expander 4;

[0045] The outlet of the hydrogen expander 4 is connected to the cold end inlet of the refrigerator 5;

[0046] The cold end outlet of the refrigerator 5 is connected to the fuel inlet of the hydrogen internal combustion engine 6;

[0047] The exhaust outlet of the hydrogen internal combustion engine 6 is connected to one end of the first branch and one end of the second branch, respectively.

[0048] The other end of the first branch is connected to the flue gas side inlet of the Rankine cycle waste heat recovery system 7 (specifically, the flue gas evaporator 7-1).

[0049] The other end of the second branch is connected to the hot end inlet of the hydrogen heater 3.

[0050] The other end of the second branch is connected to the hot end inlet of the hydrogen heater 3.

[0051] The Rankine cycle waste heat recovery system 7 is used to recover the heat of the flue gas transported in the first branch.

[0052] Hydrogen heater 3 is used to recover the heat of the flue gas transported in the second branch.

[0053] In other words, the exhaust gas from the hydrogen internal combustion engine 6 is divided into two branches. One branch is connected to the flue gas side inlet of the flue gas evaporator 7-1 in the Rankine cycle waste heat recovery system 7, and the other branch is connected to the hot end inlet of the hydrogen heater 3.

[0054] It should be noted that hydrogen storage tank 1 is pre-stored with high-pressure hydrogen (e.g., 15.2–70.9 MPa, or other pressures required by the user).

[0055] It should be noted that the hot-end fluid of the hydrogen heater 3 is the waste heat source of the hydrogen internal combustion engine. This waste heat source can be the exhaust gas from the hydrogen internal combustion engine, or the boosted air, or the cylinder liner water, or the exhaust gas recirculation gas. Figure 1 The image shows a portion of the exhaust gas from a hydrogen internal combustion engine.

[0056] The cold end fluid of the hydrogen heater 3 is high-pressure hydrogen flowing out of the hydrogen storage tank 1. The output power of the hydrogen expander 4 can be adjusted by adjusting the temperature of the hydrogen output after being heated by the hydrogen heater 3.

[0057] In this invention, specifically, the hot end outlet of the hydrogen heater 3 is connected to the external atmospheric environment, which is used to recover the heat of the flue gas flowing out of the hydrogen internal combustion engine 6 before discharging it into the external atmospheric environment.

[0058] It should be noted that the cold end inlet of the hydrogen heater 3 is connected to the cold end outlet of the hydrogen heater 3 through a connecting pipe located in the inner cavity of the hydrogen heater 3 housing.

[0059] The hot-end inlet of the hydrogen heater 3 is connected to the hot-end outlet through the inner cavity of the hydrogen heater 3's housing; that is, the hot-end outlet and the hot-end inlet are located at opposite ends of the inner cavity of the hydrogen heater 3's housing. Therefore, a portion of the flue gas discharged from the hydrogen internal combustion engine 6 enters the inner cavity of the hydrogen heater 3's housing through the hot-end inlet. At this time, the flue gas can heat the hydrogen (specifically, the hydrogen in the connecting pipe) flowing into the hydrogen heater 3's cold-end inlet.

[0060] In this invention, specifically, the hot end inlet of the refrigerator 5 is connected to a refrigerant (such as water) pipeline to deliver the refrigerant to the refrigerator 5. The refrigerant pipeline is, for example, a tap water pipeline.

[0061] The hot end outlet of the refrigerator 5 is connected to an external location requiring cooling energy, and is used to deliver cooling capacity to the external location requiring cooling energy, such as the interior environment of a hydrogen internal combustion engine vehicle, through a refrigerant (such as water) pipeline.

[0062] It should be noted that the cold-end fluid of the cooler 5 is expanded hydrogen gas, and the hot-end fluid is a cooling medium (such as chilled water). The chilled water, cooled by the hydrogen gas, can provide cooling energy to the user. The temperature of the hydrogen output from the hydrogen expander 4 can be adjusted by adjusting the heating temperature of the hydrogen gas from the hydrogen internal combustion engine in the hydrogen heater 3, thereby adjusting the cooling capacity of the cooler 5. If the hydrogen is heated to an excessively high temperature, it may lose its cooling capacity after expansion; in this case, the cooler 5 may not need to be installed.

[0063] It should be noted that the cold end inlet of the cooler 5 is connected to the cold end outlet of the cooler 5 through a connecting pipe located in the inner cavity of the cooler 5 housing.

[0064] The hot-end inlet of the refrigerator 5 is connected to the hot-end outlet through the inner cavity of the refrigerator 5's shell; that is, the hot-end outlet and the hot-end inlet are located at opposite ends of the inner cavity of the refrigerator 5's shell. Therefore, the hydrogen gas output from the hydrogen expander 4 after performing work enters the inner cavity of the refrigerator 5's shell through the cold-end inlet. At this time, the hydrogen gas can cool down the cold water (specifically, the cold water in the connecting pipe) flowing into the hot-end inlet of the refrigerator 5.

[0065] In this invention, the Rankine cycle waste heat recovery system 7 includes a flue gas evaporator 7-1, a waste heat recovery expander 7-2, a condenser 7-3, and a working fluid pump 7-4.

[0066] The working fluid outlet of the flue gas evaporator 7-1 is connected to the working fluid inlet of the expander 7-2.

[0067] The working fluid outlet of the waste heat recovery expander 7-2 is connected to the working fluid inlet of the condenser 7-3;

[0068] The working fluid outlet of condenser 7-3 is connected to the working fluid inlet of working fluid pump 7-4;

[0069] The working fluid outlet of the working fluid pump 7-4 is connected to the working fluid inlet of the flue gas evaporator 7-1;

[0070] The other end of the first branch is connected to the flue gas side inlet of the flue gas evaporator 7-1 in the Rankine cycle waste heat recovery system 7.

[0071] In practice, the flue gas outlet of the flue gas evaporator 7-1 is connected to the external atmospheric environment to recover the heat of the flue gas flowing out of the hydrogen internal combustion engine 6 before discharging it into the external atmospheric environment.

[0072] It should be noted that the flue gas inlet of the flue gas evaporator 7-1 is connected to the flue gas outlet through the inner cavity of the casing of the flue gas evaporator 7-1; that is, the flue gas inlet and the flue gas outlet are located at both ends of the inner cavity of the casing of the flue gas evaporator 7-1.

[0073] The working fluid inlet of the flue gas evaporator 7-1 is connected to the working fluid outlet of the flue gas evaporator 7-1 through a connecting pipe located in the inner cavity of the flue gas evaporator 7-1 shell. Therefore, a portion of the flue gas discharged from the hydrogen internal combustion engine 6 enters the flue gas evaporator 7-1 through the flue gas side inlet. At this time, the working fluid (liquid working fluid) flowing in through the working fluid inlet of the flue gas evaporator 7-1 can be heated to a high temperature and high pressure state.

[0074] It should be noted that in this invention, for the Rankine cycle waste heat recovery system 7, firstly, the working fluid pump 7-4 pressurizes the liquid working fluid cooled by the condenser 7-3, and then the pressurized liquid working fluid is transported to the flue gas evaporator 7-1. In the flue gas evaporator 7-1, the liquid working fluid is heated into a high-temperature and high-pressure gas by the flue gas transported by the hydrogen internal combustion engine 6, and then enters the waste heat recovery expander 7-2 to expand and do work. After doing work, the gaseous working fluid enters the condenser 7-3 and is cooled into a liquid working fluid. Finally, the liquid working fluid returns to the working fluid pump 7-4, is pressurized and transported again, and the next cycle begins.

[0075] In practice, the working fluid of the Rankine cycle waste heat recovery system 7 includes various working fluids, such as conventional refrigerants (e.g., dichloromethane) or carbon dioxide.

[0076] In practice, the cold end inlet of the condenser 7-3 is connected to an external device or location that provides a cooling medium (such as cooling water or cooling air), for example, to an external water pipe for water to flow into the external water pipe.

[0077] The cold end outlet of condenser 7-3 is connected to the external cooling water return pipe or the external atmospheric environment to discharge the heated cooling water or air.

[0078] It should be noted that the cold end inlet of condenser 7-3 is connected to the cold end outlet through the inner cavity of the shell of condenser 7-3; that is, the cold end inlet and the cold end outlet are located at both ends of the inner cavity of the shell of condenser 7-3.

[0079] The working fluid inlet of condenser 7-3 is connected to the working fluid outlet of condenser 7-3 through a connecting pipe located in the inner cavity of condenser 7-3 shell; therefore, the cold source (such as dry air or cooling water) entering through the cold end inlet of condenser 7-3 can cool the working fluid (specifically the gaseous working fluid formed after the waste heat recovery expander 7-2 expands and does work) entering through the working fluid inlet of condenser 7-3, thereby cooling it into a liquid working fluid.

[0080] It should be noted that, in this invention, the heat source of the flue gas evaporator 7-1 is the flue gas discharged from the hydrogen internal combustion engine 6, and the cold source of the flue gas evaporator 7-1 is the circulating working fluid of the Rankine cycle waste heat recovery system 7; the heat source of the condenser 7-3 is the circulating working fluid of the Rankine cycle waste heat recovery system 7, and the cold source of the condenser 7-3 is dry air or cooling water.

[0081] In practice, the hydrogen expander 4 is coaxial with the waste heat recovery expander 7-4 in the Rankine cycle waste heat recovery system 7.

[0082] It should be noted that coaxial refers to the fact that the hydrogen expander 4 and the waste heat recovery expander 7-4 share a common power output shaft.

[0083] In practice, the power output shaft of the hydrogen expander 4 and the power output shaft of the waste heat recovery expander 7-4 in the Rankine cycle waste heat recovery system 7 are coaxial through a coupling.

[0084] In this invention, by having the hydrogen expander 4 coaxial with the waste heat recovery expander 7-4 in the Rankine cycle waste heat recovery system 7, they can share an external generator, reducing system component redundancy.

[0085] To better understand this invention, the functions of each related component are described below.

[0086] Hydrogen storage tank 1 is used to store hydrogen and supply hydrogen fuel to hydrogen internal combustion engine 6;

[0087] Solenoid valve 2 is used to control the amount of hydrogen supplied to the hydrogen internal combustion engine 6;

[0088] Hydrogen heater 3 is used to heat hydrogen fuel and deliver the heated hydrogen to hydrogen expander 4;

[0089] The hydrogen expander 4 is used to expand high-temperature hydrogen to do work, thereby recovering part of the hydrogen pressure energy and the waste heat energy of the hydrogen internal combustion engine 6, and then the expanded low-temperature hydrogen is delivered to the refrigerator 5.

[0090] The cooler 5 is used to reduce the temperature of the refrigerant by using the low-temperature hydrogen delivered by the hydrogen expander 4, thereby providing cold energy to the user. The low-temperature hydrogen, after being heated by the refrigerant, then enters the hydrogen internal combustion engine 6.

[0091] The hydrogen internal combustion engine 6 is used to burn hydrogen fuel and generate power.

[0092] In this invention, the flue gas from the first branch is fed into the flue gas evaporator 7-1 of the Rankine cycle waste heat recovery system 7 to heat the working fluid. The heated working fluid pushes the waste heat recovery expander 7-2 to expand and do work, and then is cooled by the condenser 7-3. The cooled working fluid is compressed by the working fluid pump 7-4 and returns to the flue gas evaporator 7-1, and is then reheated, completing the internal cycle of the Rankine cycle waste heat recovery system.

[0093] In a specific implementation, this invention provides a multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and hydrogen storage pressure energy, which includes the following operating modes:

[0094] When the hydrogen internal combustion engine 6 is running normally, the flue gas discharged from the hydrogen internal combustion engine is divided into two branches. The flue gas in the first branch is fed into the flue gas evaporator 7-1 in the Rankine cycle waste heat recovery system 7 to heat the working fluid. The heated working fluid pushes the waste heat recovery expander 7-2 to expand and do work. Then it is cooled by the condenser 7-3. The cooled working fluid is compressed by the working fluid pump 7-4 and returned to the flue gas evaporator 7-1 to be reheated, completing the internal cycle of the Rankine cycle waste heat recovery system.

[0095] The flue gas from the second branch is used in the hydrogen heater 3 to heat the high-pressure hydrogen flowing in from the hydrogen storage tank 1 through the solenoid valve 2, thereby forming high-temperature and high-pressure hydrogen. The high-temperature and high-pressure hydrogen is then expanded by the hydrogen expander 4 to do work, and outputs power simultaneously with the waste heat recovery expander 7-4 in the Rankine cycle waste heat recovery system. After being expanded by the hydrogen expander 4 to do work, the pressure and temperature of the hydrogen are reduced, which can be used to further provide cooling in the refrigerator 5. The hydrogen output from the cold end outlet of the refrigerator 5 is used to enter the hydrogen internal combustion engine 6 for combustion.

[0096] In summary, it should be noted that, for this invention, during normal operation of the hydrogen internal combustion engine 6, a portion of the waste heat from the hydrogen internal combustion engine (e.g., flue gas waste heat) first enters the working fluid of the heating system in the Rankine cycle waste heat recovery system 7. The heated working fluid drives the expander to do work, and then the working fluid is cooled and pressurized to reabsorb the waste heat from the hydrogen internal combustion engine, completing the internal cycle of the Rankine cycle waste heat recovery system. Simultaneously, high-pressure hydrogen is input from the hydrogen storage tank 1 into the hydrogen heater 3 via the solenoid valve 2. In the hydrogen heater 3, it is heated by another portion of the waste heat from the hydrogen internal combustion engine. The high-temperature, high-pressure hydrogen expands and does work through the hydrogen expander 4, simultaneously outputting power with the waste heat recovery expander 7-4 in the Rankine cycle waste heat recovery system. The hydrogen pressure and temperature are reduced after being processed by the hydrogen expander 4.

[0097] In this invention, the temperature of the expanded hydrogen will vary significantly depending on the temperature at which the hydrogen is heated in the heater 3. The higher the temperature of the hydrogen, the greater the expansion work, but the higher the temperature of the expanded hydrogen, the less likely it will have cooling capacity. If the hydrogen is heated to a lower temperature, the temperature of the expanded hydrogen may reach tens of degrees below zero. In this case, this part of the cold energy can be recovered in the cooler 5 using a refrigerant.

[0098] The output power of the expander 4 and the cooling capacity of the refrigerator 5 are determined by the temperature at which the hydrogen is heated in the hydrogen heater 3.

[0099] To better understand the technical solution of the present invention, the working principle of the present invention is explained below.

[0100] This invention employs the Rankine cycle to recover various types of waste heat from a hydrogen internal combustion engine (including waste heat from flue gas and cylinder liner water, etc.). The working fluid in the Rankine cycle is not limited to conventional working fluids such as refrigerants or carbon dioxide. Simultaneously, a portion of the waste heat from the hydrogen internal combustion engine is used to heat high-pressure hydrogen flowing from the hydrogen storage tank. This allows the high-temperature, high-pressure hydrogen to perform work in an expander. Furthermore, depending on the heating temperature of the hydrogen, the expanded hydrogen may also possess a certain cooling capacity, providing cooling energy. This achieves efficient simultaneous utilization of both the hydrogen storage pressure energy and the waste heat energy of the hydrogen internal combustion engine.

[0101] Compared with existing technologies, the multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and hydrogen storage pressure energy provided by this invention has the following beneficial effects:

[0102] 1. The present invention is a multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and hydrogen storage pressure energy. By using part of the waste heat from the hydrogen internal combustion engine to heat high-pressure hydrogen, the working capacity of high-pressure hydrogen can be significantly improved, thereby obtaining a large amount of recovered work (i.e., it can perform expansion work) from high-temperature and high-pressure hydrogen, and significantly improving the output power of the entire energy recovery system.

[0103] 2. In the system of the present invention, the low-temperature hydrogen gas formed after expansion and work may also have a certain refrigeration capacity, which can provide additional refrigeration, thereby realizing the full utilization of thermal energy and pressure energy in multiple stages.

[0104] It should be noted that the content of this invention is also applicable to waste heat recovery systems with other layouts, and is not limited to the Rankine cycle waste heat recovery system 7 described above. That is, the Rankine cycle waste heat recovery system 7 is a waste heat recovery system in a broad sense, and is not limited to... Figure 1 The layout is shown. For example, other waste heat recovery systems may employ intermediate regeneration, multi-stage compression or expansion, or different flow distribution structures, etc.

[0105] In summary, compared with existing technologies, the multi-stage energy utilization system for recovering waste heat and hydrogen pressure energy from hydrogen internal combustion engines provided by this invention is scientifically designed and can effectively recover and utilize the waste heat and pressure energy generated during the operation of hydrogen internal combustion engines in multiple stages. It fully recovers and utilizes the waste heat energy of hydrogen internal combustion engines and the hydrogen pressure energy of hydrogen storage tanks, achieving multi-stage and efficient energy utilization, which has significant practical significance.

[0106] Based on the multi-stage energy utilization system provided by this invention, a portion of the waste heat from the hydrogen internal combustion engine is utilized by the Rankine cycle waste heat recovery system to generate useful work, while another portion of the waste heat is used to heat the high-pressure hydrogen at the outlet of the hydrogen storage tank to obtain high-temperature and high-pressure hydrogen, which can then expand and perform work. The low-temperature and low-pressure hydrogen formed after expansion and work can further release its cooling capacity in the refrigerator as needed, and then enter the hydrogen internal combustion engine for combustion. Therefore, the waste heat energy of the hydrogen internal combustion engine and the hydrogen pressure energy of the hydrogen storage tank are fully utilized.

[0107] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and hydrogen storage pressure energy, characterized in that, It includes a hydrogen storage tank (1), a solenoid valve (2), a hydrogen heater (3), a hydrogen expander (4), a refrigerator (5), a hydrogen internal combustion engine (6), and a Rankine cycle waste heat recovery system (7); The outlet of the hydrogen storage tank (1) is connected to the inlet of the solenoid valve (2); The outlet of the solenoid valve (2) is connected to the cold end inlet of the hydrogen heater (3); The cold end outlet of the hydrogen heater (3) is connected to the inlet of the hydrogen expander (4); The outlet of the hydrogen expander (4) is connected to the cold end inlet of the refrigerator (5); The cold end outlet of the refrigerator (5) is connected to the fuel inlet of the hydrogen internal combustion engine (6); The exhaust outlet of the hydrogen internal combustion engine (6) is connected to one end of the first branch and one end of the second branch, respectively; The other end of the first branch is connected to the flue gas side inlet of the Rankine cycle waste heat recovery system (7); The other end of the second branch is connected to the hot end inlet of the hydrogen heater (3); The Rankine cycle waste heat recovery system (7) is used to recover the heat of the flue gas transported in the first branch; Hydrogen heater (3) is used to recover the heat of the flue gas transported in the second branch.

2. The multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and hydrogen storage pressure energy as described in claim 1, characterized in that, The hot end outlet of the hydrogen heater (3) is connected to the external atmospheric environment; The hot end inlet of the refrigeration unit (5) is connected to the refrigerant pipeline; The hot end outlet of the refrigeration unit (5) is connected to the external location where cooling energy is required.

3. The multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and hydrogen storage pressure energy as described in claim 1, characterized in that, The Rankine cycle waste heat recovery system (7) includes a flue gas evaporator (7-1), a waste heat recovery expander (7-2), a condenser (7-3), and a working fluid pump (7-4); The working fluid outlet of the flue gas evaporator (7-1) is connected to the working fluid inlet of the expander (7-2); The working fluid outlet of the waste heat recovery expander (7-2) is connected to the working fluid inlet of the condenser (7-3); The working fluid outlet of the condenser (7-3) is connected to the working fluid inlet of the working fluid pump (7-4); The working fluid outlet of the working fluid pump (7-4) is connected to the working fluid inlet of the flue gas evaporator (7-1); The other end of the first branch is connected to the flue gas side inlet of the flue gas evaporator (7-1) of the Rankine cycle waste heat recovery system (7).

4. The multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and hydrogen storage pressure energy as described in claim 3, characterized in that, The flue gas outlet of the flue gas evaporator (7-1) is connected to the external atmospheric environment; The cold end inlet of the condenser (7-3) is connected to an external device or location that provides cooling water or cooling air; The cold end outlet of the condenser (7-3) is connected to the external cooling water return pipeline or the external atmospheric environment.

5. The multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and hydrogen storage pressure energy as described in claim 3, characterized in that, The hydrogen expander (4) is coaxial with the waste heat recovery expander (7-2) in the Rankine cycle waste heat recovery system (7).

6. The multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and hydrogen storage pressure energy as described in claim 5, characterized in that, The power output shaft of the hydrogen expander (4) and the power output shaft of the waste heat recovery expander (7-2) in the Rankine cycle waste heat recovery system (7) are coaxial through a coupling.

7. The multi-stage energy utilization system for recovering waste heat from hydrogen internal combustion engines and hydrogen storage pressure energy as described in any one of claims 1 to 6, characterized in that, The following working modes are included: When the hydrogen internal combustion engine (6) is running normally, the exhaust gas from the hydrogen internal combustion engine is divided into two branches. The exhaust gas from the first branch is fed into the flue gas evaporator (7-1) in the Rankine cycle waste heat recovery system (7) to heat the working fluid. The heated working fluid pushes the waste heat recovery expander (7-2) to expand and do work. Then it is cooled by the condenser (7-3). The cooled working fluid is compressed by the working fluid pump (7-4) and returned to the flue gas evaporator (7-1) to be reheated, thus completing the internal cycle of the Rankine cycle waste heat recovery system. The flue gas from the second branch is used in the hydrogen heater (3) to heat the high-pressure hydrogen flowing in from the hydrogen storage tank (1) through the solenoid valve (2), thereby forming high-temperature and high-pressure hydrogen. The high-temperature and high-pressure hydrogen is then expanded by the hydrogen expander (4) to do work, and outputs power simultaneously with the waste heat recovery expander (7-2) in the Rankine cycle waste heat recovery system. After the hydrogen expander (4) expands and does work, the pressure and temperature of the hydrogen are reduced, which can be used to further provide cooling in the refrigerator (5), and the hydrogen output from the cold end outlet of the refrigerator (5) is used to enter the hydrogen internal combustion engine (6) for combustion.

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