A hydrogen internal combustion locomotive exhaust heat recovery device and method

Abstract

The present invention discloses a heat recovery device and method for exhaust gas of a hydrogen internal combustion engine, including a power room hydrogen internal combustion engine, the heat recovery device is arranged above the power room hydrogen internal combustion engine, the heat recovery device includes a heat exchange box, and the exhaust gas of the power room hydrogen internal combustion engine is processed by the heat exchange box; the heat exchange box includes a primary heat exchange box and a secondary heat exchange box, the primary heat exchange box is used for converting methanol and high-temperature water into high-temperature and high-pressure mixed steam for processing, and the high-temperature and high-pressure mixed steam is used for hydrogen production; the secondary heat exchange box is used for heat exchange treatment between desalted water and the exhaust gas of the power room hydrogen internal combustion engine, and the heat exchange treatment heats the desalted water to recover exhaust gas energy. The present invention can use the heat in the exhaust gas to convert methanol and water into high-temperature and high-pressure mixed steam and transport it to the hydrogen production device for producing hydrogen for use in the hydrogen internal combustion engine.

Description

Technical Field

[0001] The present invention relates to the technical field of heat recovery devices for rail transit vehicles, and particularly relates to a hydrogen internal combustion locomotive exhaust heat recovery device and method. Background Art

[0002] In the field of rail transit, non-electrified railways will still exist for a long time and account for a large proportion. Traditional internal combustion locomotives used in non-electrified railways will face huge challenges in energy conservation and emission reduction. Hydrogen energy is regarded as one of the cleanest energy sources with the most promising application prospects due to its zero pollution, high efficiency, and rich sources. The main utilization methods of hydrogen energy are fuel cells and hydrogen internal combustion engines. Fuel cells have the advantages of high efficiency and zero emissions, but they have the disadvantages of high cost, low lifespan, small single-stack power, and high requirements for hydrogen purity compared with hydrogen internal combustion engines. Hydrogen internal combustion engines have a thermal efficiency close to that of fuel cells, can achieve low emissions, and have advantages such as low cost, long lifespan, and a wide range of gas adaptability. Hydrogen energy is an important carrier for promoting the upgrading and transformation of various application fields of traditional internal combustion engines and assisting in carbon peak & carbon neutrality.

[0003] In the ground power generation application scenario of traditional internal combustion engines, the heat in the exhaust can be recovered through combined heat and power supply to improve the thermal efficiency of the unit; for traditional internal combustion locomotives, the heat recovered according to ground combined heat and power supply has nowhere to be used, and the diesel engine exhaust is directly discharged into the atmosphere. Hydrogen internal combustion locomotives use hydrogen as fuel, and the combustion exhaust temperature is higher than that of diesel engines. Recycling the heat in the exhaust for on-vehicle methanol reforming to produce hydrogen can solve the locomotive fuel supply and improve the locomotive energy efficiency.

[0004] The invention patent application with the application number CN202110057274.4 discloses a diesel engine exhaust waste heat recovery and utilization system based on methanol steam reforming to produce hydrogen, which is provided with a reforming hydrogen production reactor for generating hydrogen-rich reforming gas from methanol steam, and also provided with an adsorption hydrogen storage module with multiple hydrogen storage units; the system receives high-temperature exhaust through a heat supply gas path, and uses an exhaust gas distributor to distribute the received high-temperature exhaust to the reforming hydrogen production reactor and multiple hydrogen storage units for heat supply according to the chemical reaction environment requirements. The working conditions of the hydrogen storage units can be switched between the adsorption working condition and the desorption working condition; in the adsorption hydrogen storage module, the hydrogen storage unit in the adsorption working condition adsorbs and stores the hydrogen component in the hydrogen-rich reforming gas, and the hydrogen storage unit in the desorption working condition releases the hydrogen it stores and supplies hydrogen to external devices; the invention can utilize methanol steam reforming to recover the waste heat of the exhaust according to the specific emission conditions of marine diesel engines, and comprehensively utilize this part of energy through the methods of in-cylinder blending, metal hydride hydrogen storage, and fuel cells.

[0005] The invention patent application with application number CN202110824398.0 discloses a hydrogen-ammonia dual-fuel engine system that utilizes waste heat from exhaust gas to catalytically reform methanol to supply hydrogen, including a methanol aqueous solution tank, a methanol pump, a methanol flowmeter, a catalytic reformer, a condenser, a filter, a pneumatic booster pump, a hydrogen flowmeter, a hydrogen pressure sensor, a flame retardant, a hydrogen rail, a hydrogen nozzle, an ammonia fuel engine, an electronic control unit ECU and an exhaust gas drive and emission mechanism; the invention uses methanol as a hydrogen energy carrier to realize convenient storage and transportation, and utilizes the waste heat from the engine's exhaust gas to catalytically reform methanol to produce hydrogen to realize hydrogen supply; provides real-time, quantitative and constant pressure online hydrogen supply according to the specific operating conditions of the engine, without the need for additional excess hydrogen storage devices; adjusts the injection pressure and injection amount of hydrogen according to the specific operating conditions of the ammonia fuel engine, effectively improves the combustion of the engine under various operating conditions, and reduces NOx emissions; enriches the carbon-free alternative energy combustion mode and supply method of the internal combustion engine, and increases the direction and strategic deployment of energy transformation. The above two invention patent applications only send the exhaust gas into the hydrogen production equipment and do not disclose the specific energy conversion and energy recovery principles and processes. Summary of the invention

[0006] The purpose of the present invention is to provide a heat recovery device and method for exhaust gas of a hydrogen internal combustion engine, which includes a hydrogen internal combustion engine in a power room, wherein the heat recovery device is arranged above the hydrogen internal combustion engine in the power room, and the heat recovery device includes a heat exchange box, and the exhaust gas of the hydrogen internal combustion engine in the power room is processed by the heat exchange box; the heat exchange box includes a primary heat exchange box and a secondary heat exchange box, wherein the primary heat exchange box is used for converting methanol and high-temperature water into high-temperature and high-pressure mixed steam for processing, and the high-temperature and high-pressure mixed steam is used for hydrogen production; the secondary heat exchange box is used for heat exchange between desalted water and the exhaust gas of the hydrogen internal combustion engine in the power room, and the heat exchange process heats the desalted water to recover the exhaust gas energy. The present invention can utilize the heat in the exhaust gas to convert methanol and water into high-temperature and high-pressure mixed steam and transport it to the hydrogen production device for producing hydrogen for use in the hydrogen internal combustion engine.

[0007] The technical solution adopted by the present invention is as follows:

[0008] The present invention discloses an exhaust heat recovery device for a hydrogen internal combustion locomotive, comprising a hydrogen internal combustion engine in a power room, wherein the heat recovery device is arranged above the hydrogen internal combustion engine in the power room, and the heat recovery device comprises a heat exchange box, and the exhaust gas of the hydrogen internal combustion engine in the power room is processed by the heat exchange box;

[0009] The heat exchange box includes a primary heat exchange box and a secondary heat exchange box. The primary heat exchange box is used to convert methanol and high-temperature water into high-temperature and high-pressure mixed steam for processing, and the high-temperature and high-pressure mixed steam is used for hydrogen production; the secondary heat exchange box is used to perform heat exchange treatment between desalted water and the exhaust gas of the hydrogen internal combustion engine in the power room, and the heat exchange treatment heats the desalted water to recover exhaust energy.

[0010] Further, the heat exchange box includes an intermediate box body, an intake pipe, an exhaust pipe, and an end cover. The intake pipe is connected to the primary heat exchange box, the exhaust pipe is connected to the secondary heat exchange box, and the end cover connects the primary heat exchange box and the secondary heat exchange box to communicate the exhaust passage of the heat exchange box. The intake pipe includes an air inlet, and the exhaust pipe includes an exhaust port.

[0011] Further, a first tube bundle is arranged in the primary heat exchange box. The first tube bundle is the exhaust passage of the hydrogen internal combustion engine in the power chamber of the primary heat exchange box. Baffles are arranged at intervals in the primary heat exchange box, and the baffles are used to increase the heat transfer area and the heat exchange time for treatment. A second tube bundle is arranged in the secondary heat exchange box.

[0012] Further, the primary heat exchange box and the secondary heat exchange box are of a shell-and-tube structure. The first tube bundle and the second tube bundle are connected and used for the exhaust heat exchange treatment of the hydrogen internal combustion engine in the power chamber. The shell sides of the primary heat exchange box and the secondary heat exchange box are each closed.

[0013] Further, a second pressure relief valve, a high-temperature water outlet, a liquid level sensor, and a water filling port are arranged on the secondary heat exchange box. The position where the liquid level sensor is arranged is higher than the position of the high-temperature water outlet.

[0014] Further, a high-temperature water injection port, a methanol injection port, a first pressure relief valve, a temperature sensor, a pressure sensor, and a high-temperature steam outlet are arranged on the primary heat exchange box. The opening pressure of the first pressure relief valve is set to be 1.5 - 2 times the methanol reforming hydrogen production operating pressure.

[0015] Further, the high-temperature water injection port and the methanol injection port are arranged at one end of the primary heat exchange box away from the air inlet, the high-temperature steam outlet is arranged at one end close to the air inlet, and the first pressure relief valve, the temperature sensor, and the pressure sensor are arranged below the high-temperature steam outlet;

[0016] The high-temperature water injection port and the methanol injection port are used to input methanol and high-temperature water into the primary heat exchange box. The methanol and the high-temperature water flow from the high-temperature water injection port and the methanol injection port towards the air inlet direction and flow in the opposite direction to the exhaust gas in the first tube bundle.

[0017] The present invention discloses a method for recovering the heat of the exhaust of a hydrogen internal combustion locomotive. The exhaust of the hydrogen internal combustion locomotive generates a gas medium. The gas medium passes through the air inlet, flows into the first tube bundle of the primary heat exchange box in the intake pipe, the gas medium flows into the second tube bundle of the secondary heat exchange box through the end cover, and finally is discharged outside the vehicle through the exhaust pipe. The heat recovery method includes the following steps:

[0018] S1: Desalted water is injected into the secondary heat exchange box for heating, and then the heated desalted water is taken out from the high-temperature water outlet through a pump and enters the primary heat exchange box through the high-temperature water injection port. At the same time, a solution formed by methanol and water enters the primary heat exchange box through the methanol injection port in proportion;

[0019] S2: The solution of methanol and water flows back and forth and mixes among the first tube bundles through the baffle plate in the primary heat exchange tank and is heated to form a uniform high-temperature and high-pressure methanol-water mixed vapor.

[0020] S3: The high-temperature steam outlet is connected to a flow control valve. When the temperature sensor and the pressure sensor detect that the temperature of the methanol-water mixed vapor reaches the hydrogen production requirement, the flow control valve transports the high-temperature steam to the methanol hydrogen production equipment to produce hydrogen.

[0021] Furthermore, a liquid level sensor and a second pressure relief valve are arranged on the secondary heat exchange tank. When the liquid level sensor detects that the water level in the secondary heat exchange tank is too low, it controls the water inlet to increase the flow rate; when there is too much water injection or too high pressure in the secondary heat exchange tank, the second pressure relief valve is used for pressure relief protection.

[0022] Furthermore, the flow rates of methanol and water injected into the primary heat exchange tank are adjusted according to the temperature sensor, the pressure sensor and the hydrogen production demand, and the pressure in the primary heat exchange tank is protected against pressure relief through the first pressure relief valve.

[0023] The technical effects of the present invention are as follows:

[0024] The present invention provides a heat recovery device and method for the exhaust of a hydrogen internal combustion locomotive. Recovering the heat in the exhaust for on-vehicle methanol hydrogen production can solve the fuel supply of the locomotive and improve the energy efficiency of the locomotive.

[0025] Specifically as follows:

[0026] 1. The heat recovery device of the present invention adopts two-stage heat exchange. The primary heat exchange adopts spraying and then passes through the baffle plate to increase the heat transfer area and heat exchange time, and the flow directions of the internal and external media of the first tube bundle are opposite; the secondary heat exchange adopts immersion heat exchange, and the energy recovery effect of the device is greatly improved.

[0027] 2. The heat recovery device of the present invention adopts a detachable structure, which is convenient for cleaning and maintenance to ensure the heat recovery effect. Description of the Drawings

[0028] Figure 1 is a schematic structural diagram of the heat recovery device of the present invention;

[0029] Figure 2 is a schematic internal structure diagram of the heat recovery device of the present invention;

[0030] Markings in the figure: 1 - primary heat exchange box, 2 - secondary heat exchange box, 3 - intake pipe, 4 - exhaust pipe, 5 - end cover, 6 - air inlet, 7 - exhaust port, 8 - water spray inlet, 9 - methanol spray inlet, 10 - first pressure relief valve, 11 - temperature sensor, 12 - pressure sensor, 13 - steam outlet, 14 - second pressure relief valve, 15 - water outlet, 16 - liquid level sensor, 17 - water filling port, 18 - first tube bundle, 19 - baffle plate, 20 - second tube bundle. Detailed implementation mode

[0031] The following combines the attached drawings to make a detailed description of the present invention.

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the following further details the present invention in combination with the attached drawings and embodiments.

[0033] In this embodiment, the data adopted are preferred solutions, but they do not limit the present invention;

[0034] In this embodiment, the hydrogen internal combustion locomotive uses a hydrogen internal combustion engine as the power source, and the fuel is hydrogen. The hydrogen is mainly produced by recovering the heat in the exhaust of the hydrogen internal combustion engine and combining with the methanol reforming hydrogen production process. The above methanol reforming hydrogen production process is as follows: methanol + demineralized water at 220°C to 280°C, 0.8 MPa to 2.5 MPa, in the presence of a catalyst, methanol and water are converted into about 75% hydrogen, 24% CO2 and a very small amount of CO, CH4.

[0035] Furthermore, generating 1 kg of hydrogen requires absorbing 14.567 MJ of energy. Taking a 100 kW hydrogen internal combustion engine as an example, the hourly hydrogen consumption is about 7.5 kg. Generating 7.5 kg of hydrogen requires 7.5×14.567 = 110 MJ of energy. The thermal efficiency of the hydrogen internal combustion engine is about 40%, and the exhaust gas accounts for one-third of the fuel energy. Using 37% of the energy in the exhaust gas for methanol cracking to produce hydrogen can meet the hydrogen consumption. Therefore, the exhaust gas of the internal combustion engine is used to exchange heat with methanol and water, and the methanol and water are converted into high-temperature and high-pressure steam and then transported to the hydrogen production module to produce hydrogen.

[0036] Embodiment 1

[0037] As Figure 1-2 shown, this embodiment provides a device for recovering the exhaust heat of a hydrogen internal combustion locomotive, including a hydrogen internal combustion engine in the power chamber. The heat recovery device is arranged above the hydrogen internal combustion engine in the power chamber. The heat recovery device includes a heat exchange box, and the exhaust gas of the hydrogen internal combustion engine in the power chamber is processed through the heat exchange box;

[0038] The heat exchange box includes a primary heat exchange box 1 and a secondary heat exchange box 2. The primary heat exchange box 1 is used for processing methanol and high-temperature water into high-temperature and high-pressure mixed steam, and the high-temperature and high-pressure mixed steam is used for hydrogen production. The secondary heat exchange box 2 is used for heat exchange between desalted water and the exhaust gas of the hydrogen internal combustion engine in the power chamber, and the heat exchange process heats the desalted water to recover the exhaust gas energy.

[0039] In this embodiment, the temperature of the steam after the methanol-water mixed solution absorbs the exhaust heat (primary heat exchange) and vaporizes must reach above 220°C to 280°C or more to meet the requirements of the hydrogen production process. Therefore, the exhaust temperature after heat exchange must be higher than 220°C to 280°C. The exhaust temperature after primary heat exchange is still relatively high and contains a large amount of heat. If the exhaust gas after primary heat exchange is subjected to a second heat exchange with the methanol-water mixed solution, and then the methanol aqueous solution is quantitatively heat-exchanged and vaporized with the exhaust gas, the utilization of the exhaust heat can be further improved.

[0040] Since the boiling point of methanol is relatively low and its heat of vaporization is also much lower than that of water, in the secondary heat exchange process, the methanol in the methanol-water mixed solution vaporizes prior to water, which is not conducive to controlling the ratio of methanol to water sprayed into the primary heat exchanger.

[0041] Therefore, in this embodiment, a device for recovering the exhaust heat of a hydrogen internal combustion locomotive is disclosed, which includes a process of primary heat exchange and secondary heat exchange. The primary heat exchange is used to convert methanol and high-temperature water into high-temperature and high-pressure mixed steam for hydrogen production; the secondary heat exchange is used for heat exchange between desalted water and the exhaust gas to heat the water and further recover the exhaust gas energy.

[0042] In this embodiment, the heat exchange box includes an intermediate box body, an air inlet pipe 3, an exhaust pipe 4, and an end cover 5. The air inlet pipe 3 is connected to the primary heat exchange box 1, the exhaust pipe 4 is connected to the secondary heat exchange box 2, and the end cover 5 connects the primary heat exchange box 1 and the secondary heat exchange box 2 to communicate the exhaust passage of the heat exchange box. The air inlet pipe 3 includes an air inlet 6, and the exhaust pipe 4 includes an exhaust port 7.

[0043] Furthermore, the end cover 5 is movably connected to the intermediate box body, the air inlet pipe 3 and the intermediate box body, and the exhaust pipe 4 and the intermediate box body, which is convenient for cleaning and maintaining the heat exchange box; preferably, the specific shapes of the air inlet pipe 3 and the exhaust pipe 4 can be adjusted according to the layout of the locomotive.

[0044] In this embodiment, the heat recovery device is arranged above the hydrogen internal combustion engine in the power chamber, and the device has a certain sound insulation effect and can be used to replace the traditional locomotive muffler.

[0045] In this embodiment, a first tube bundle 18 is arranged in the primary heat exchange tank 1. The first tube bundle 18 is the exhaust passage of the hydrogen internal combustion engine in the power chamber of the primary heat exchange tank 1. Baffle plates 19 are arranged at intervals in the primary heat exchange tank 1, and the baffle plates 19 are used to increase the heat transfer area and process the heat exchange time. A second tube bundle 20 is arranged in the secondary heat exchange tank 2.

[0046] In this embodiment, the primary heat exchange tank 1 and the secondary heat exchange tank 2 are of a shell-and-tube structure. The first tube bundle 18 and the second tube bundle 20 are connected and used for the exhaust heat exchange treatment of the hydrogen internal combustion engine in the power chamber. The shell sides of the primary heat exchange tank 1 and the secondary heat exchange tank 2 are each closed.

[0047] In this embodiment, a second pressure relief valve 14, a high-temperature water outlet 15, a liquid level sensor 16, and a water filling port 17 are arranged on the secondary heat exchange tank 2. The position where the liquid level sensor 16 is arranged is higher than the position of the high-temperature water outlet 15.

[0048] In this embodiment, a high-temperature water injection port 8, a methanol injection port 9, a first pressure relief valve 10, a temperature sensor 11, a pressure sensor 12, and a high-temperature steam outlet 13 are arranged on the primary heat exchange tank 1. The opening pressure of the first pressure relief valve 10 is 1.5 - 2 times the methanol reforming hydrogen production operation pressure, and the opening pressure of the second pressure relief valve 14 is relatively low, and 1.5 bar can be selected.

[0049] In this embodiment, the high-temperature water injection port 8 and the methanol injection port 9 are arranged at one end of the primary heat exchange tank 1 far from the air inlet 6, the high-temperature steam outlet 13 is arranged at one end close to the air inlet 6, and the first pressure relief valve 10, the temperature sensor 11, and the pressure sensor 12 are arranged below the high-temperature steam outlet 13;

[0050] Further, as Figure 1 shown, the baffle plate 19 close to the intake pipe 3 is set as the head baffle plate 19, and the baffle plate 19 close to the end cover 5 is set as the tail baffle plate 19. The high-temperature water injection port 8 and the methanol injection port 9 are arranged at the upper left side of the tail baffle plate 19, and the high-temperature steam outlet 13 is arranged on the right side of the head baffle plate 19; the first pressure relief valve 10, the temperature sensor 11, and the pressure sensor 12 are arranged on the right side of the head baffle plate 19, close to the high-temperature steam outlet 13. Adopting the above arrangement can improve the heat exchange efficiency and ensure the effectiveness of the sensor data for easy control.

[0051] The high-temperature water injection port 8 and the methanol injection port 9 are used to input methanol and high-temperature water into the primary heat exchange tank 1. The methanol and the high-temperature water flow from the high-temperature water injection port 8 and the methanol injection port 9 towards the air inlet 6 direction, flowing in the opposite direction to the exhaust gas in the first tube bundle 18.

[0052] In this embodiment, the secondary heat exchange tank 2 adopts immersion heat exchange, and the energy recovery effect of the device is greatly improved.

[0053] Embodiment 2

[0054] As Figure 1-2 shown, this embodiment provides a method for recovering the heat of the exhaust gas of a hydrogen internal combustion locomotive. The exhaust gas of the hydrogen internal combustion locomotive generates a gas medium. The gas medium passes through the air inlet 6 and flows into the first tube bundle 18 of the primary heat exchange tank 1 in the intake pipe 3. The gas medium passes through the end cover 5 and flows into the second tube bundle 20 of the secondary heat exchange tank 2, and finally is discharged outside the vehicle through the exhaust pipe 4. The heat recovery method includes the following steps:

[0055] S1: Demineralized water is injected into the secondary heat exchange tank 2 from the water filling port 17 for heating, and then the heated demineralized water is taken out from the high-temperature water outlet 15 by a pump and enters the primary heat exchange tank 1 through the high-temperature water injection port 8. At the same time, the solution formed by methanol and water enters the primary heat exchange tank 1 from the methanol injection port 9 in proportion.

[0056] S2: In the primary heat exchange tank 1, the solution of methanol and water flows back and forth and mixes between the first tube bundles 18 through the baffle plate 19 and is heated to form a uniform high-temperature and high-pressure methanol-water mixed steam.

[0057] S3: The high-temperature steam outlet 13 is connected to a flow control valve. When the temperature sensor 11 and the pressure sensor 12 detect that the temperature of the methanol-water mixed steam reaches the hydrogen production requirement, the flow control valve transports the high-temperature steam to the methanol hydrogen production equipment to produce hydrogen.

[0058] In this embodiment, a liquid level sensor 16 and a second pressure relief valve 14 are provided on the secondary heat exchange tank 2. When the liquid level sensor 16 detects that the water level in the secondary heat exchange tank 2 is too low, it controls the water filling port 17 to increase the flow rate; when there is too much water injection or too high pressure in the secondary heat exchange tank 2, the second pressure relief valve 14 is used for pressure relief protection.

[0059] In this embodiment, the flow rates of methanol and water injected into the primary heat exchange tank 1 are adjusted according to the temperature sensor 11, the pressure sensor 12, and the hydrogen production demand. When the pressure in the primary heat exchange tank 1 is too high, pressure relief protection is carried out through the first pressure relief valve 10.

[0060] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydrogen internal combustion locomotive exhaust heat recovery device, including a hydrogen internal combustion engine in the power chamber, characterized in that, the heat recovery device is arranged above the hydrogen internal combustion engine in the power chamber, and the heat recovery device includes a heat exchange box, and the exhaust gas of the hydrogen internal combustion engine in the power chamber is processed through the heat exchange box; the heat exchange box includes a primary heat exchange box and a secondary heat exchange box. The primary heat exchange box is used for processing the conversion of methanol and water into mixed steam, and the mixed steam is used for hydrogen production; the secondary heat exchange box is used for heat exchange between desalted water and the exhaust gas of the hydrogen internal combustion engine in the power chamber, and the heat exchange process heats the desalted water to recover the exhaust gas energy; the heat exchange box includes an intermediate box body, an intake pipe, an exhaust pipe and an end cover. The intake pipe is connected to the primary heat exchange box, the exhaust pipe is connected to the secondary heat exchange box, and the end cover connects the primary heat exchange box and the secondary heat exchange box to communicate the exhaust gas channel of the heat exchange box; the intake pipe includes an air inlet, and the exhaust pipe includes an exhaust port; a first tube bundle is arranged in the primary heat exchange box. The first tube bundle is the exhaust gas channel of the hydrogen internal combustion engine in the primary heat exchange box. Baffle plates are arranged at intervals in the primary heat exchange box, and the baffle plates are used for increasing the heat transfer area and heat exchange time; a second tube bundle is arranged in the secondary heat exchange box; a water spray inlet, a methanol spray inlet, a first pressure relief valve, a temperature sensor, a pressure sensor and a steam outlet are arranged on the primary heat exchange box, and the opening pressure of the first pressure relief valve is set to be 1.5 - 2 times the operation pressure of methanol reforming for hydrogen production; the water spray inlet and the methanol spray inlet are arranged at one end of the primary heat exchange box far from the air inlet, the steam outlet is arranged at one end close to the air inlet, and the first pressure relief valve, the temperature sensor and the pressure sensor are arranged below the steam outlet; the water spray inlet and the methanol spray inlet are used for inputting methanol and water into the primary heat exchange box. The methanol and water flow from the water spray inlet and the methanol spray inlet towards the air inlet direction, and flow in the opposite direction to the exhaust gas in the first tube bundle.

2. The hydrogen internal combustion locomotive exhaust heat recovery device according to claim 1, characterized in that, the primary heat exchange box and the secondary heat exchange box are of a shell - and - tube structure. The first tube bundle and the second tube bundle are connected and used for exhaust heat exchange treatment of the hydrogen internal combustion engine in the power chamber, and the shell - side of the primary heat exchange box and the secondary heat exchange box are each closed.

3. The hydrogen internal combustion locomotive exhaust heat recovery device according to claim 2, characterized in that, a second pressure relief valve, a water outlet, a liquid level sensor and a water filling port are arranged on the secondary heat exchange box, and the position of the liquid level sensor is higher than the position of the water outlet.

4. The heat recovery method of the hydrogen internal combustion locomotive exhaust heat recovery device according to claim 1. The exhaust gas of the hydrogen internal combustion locomotive generates a gas medium. The gas medium passes through the air inlet, flows into the first tube bundle of the primary heat exchange box in the intake pipe, the gas medium flows into the second tube bundle of the secondary heat exchange box through the end cover, and finally is discharged outside the vehicle through the exhaust pipe, characterized in that, the heat recovery method includes the following steps: S1: Desalted water is injected into the secondary heat exchange box for heating, and then the heated desalted water is taken out from the water outlet by a pump and enters the primary heat exchange box through the water spray inlet. At the same time, a solution formed by methanol and water enters the primary heat exchange box through the methanol spray inlet according to a proportion. S2: In the primary heat exchange tank, the methanol-water solution flows back and forth between the first tube bundles through the baffle plates for mixing and heating, forming a uniform methanol-water mixed vapor. S3: The steam outlet is connected to a flow control valve. When the temperature sensor and the pressure sensor detect that the temperature of the methanol-water mixed vapor reaches the hydrogen production requirement, the flow control valve transports the steam to the methanol hydrogen production equipment to produce hydrogen.

5. The heat recovery method of the exhaust heat recovery device for a hydrogen internal combustion locomotive according to claim 4, characterized in that, a liquid level sensor and a second pressure relief valve are provided on the secondary heat exchange tank. When the liquid level sensor detects that the water level in the secondary heat exchange tank is too low, it controls the water filling port to increase the flow rate; when there is too much water injection or too high pressure in the secondary heat exchange tank, the second pressure relief valve is used for pressure relief protection.

6. The heat recovery method of the exhaust heat recovery device for a hydrogen internal combustion locomotive according to claim 5, characterized in that, the flow rates of methanol and water injected into the primary heat exchange tank are adjusted according to the temperature sensor, the pressure sensor and the hydrogen production demand, and the pressure in the primary heat exchange tank is protected from overpressure by the first pressure relief valve.

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