Compact reaction device and system for producing hydrogen from methanol through waste heat recovery

Abstract

The embodiment of the invention provides a compact type methanol hydrogen production reaction device and system capable of recovering waste heat, and belongs to the technical field of waste heat hydrogen production chemical reactors. The reaction device comprises a plurality of stacked methanol-to-hydrogen reactor units, and each methanol-to-hydrogen reactor unit comprises a flue gas cavity plate in which a flowing channel suitable for conveying high-temperature flue gas is formed; the reaction cavity plate is closely attached to the smoke cavity plate, a groove is formed in the surface, facing the smoke cavity plate, of the reaction cavity plate, and the groove and the smoke cavity plate cooperate to form a flowing channel for a methanol working medium to flow from the first input end to the first output end; and each catalyst bed layer is laid in the corresponding groove, so that the flowing methanol working medium is subjected to reforming or cracking reaction to obtain mixed gas containing a hydrogen product, and the mixed gas exchanges heat with the high-temperature flue gas. The temperature of the catalyst bed layer is gradually reduced in the direction from the first input end to the first output end so as to be matched with the continuously-reduced flue gas temperature in the waste heat recovery process in a stepped mode.

Description

Technical Field

[0001] At least one embodiment of the present invention relates to the field of waste heat hydrogen production chemical reactor technology, and more particularly to a compact waste heat recovery methanol hydrogen production reactor and system. Background Technology

[0002] Faced with the shortage of fossil fuels and environmental pollution, there is a need to develop and utilize clean, pollution-free, and efficient energy sources. Hydrogen is widely available, has a high calorific value, produces water as a reaction product, and is easily and diversely obtained, possessing advantages such as high efficiency, cleanliness, and sustainable development, and thus has great potential. In energy and power systems, power units (gas turbines, internal combustion engines, etc.) generate a large amount of waste heat from exhaust gases. This waste heat is mainly recovered and utilized through heating and driving absorption refrigeration, but this approach has limitations such as low waste heat recovery efficiency and supply-demand mismatch.

[0003] In related technologies, methanol reforming or cracking reactions are often driven by external combustion or waste heat recovery. Furthermore, heat transfer oil is frequently used as the circulating heat medium, first transferring heat to the oil before it is fed into a fixed-bed reactor to drive the chemical hydrogen production reaction. This process adds a flue gas-heat transfer oil heat exchange process, requiring additional circulation, expansion, and storage devices for the oil, increasing the complexity of the reaction apparatus and resource consumption, and hindering compact or mobile hydrogen production. The flue gas-heat transfer oil heat exchange also causes heat damage and energy loss to the waste heat, hindering efficient recovery of waste heat.

[0004] In addition, in existing technologies, methanol thermochemical reforming or cracking to produce hydrogen mainly uses catalyst particles packed in the bed. On the one hand, this causes a large bed resistance, and on the other hand, its poor thermal conductivity leads to uneven temperature distribution of the catalyst and the bed, which easily results in large temperature differences. This causes some areas to have low catalytic activity, while the catalyst in high-temperature areas is prone to overheating and deactivation, reducing the catalyst utilization rate and service life.

[0005] Therefore, how to balance the efficient utilization of waste heat flue gas with hydrogen production efficiency and safety has become an urgent technical challenge. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a compact waste heat recovery methanol-to-hydrogen reactor, comprising multiple stacked methanol-to-hydrogen reactor units. Each methanol-to-hydrogen reactor unit includes: a flue gas chamber plate, with a flow channel formed within the flue gas chamber plate suitable for conveying high-temperature flue gas; a reaction chamber plate, which is sealed and fitted to the flue gas chamber plate, with a groove formed on the surface of the reaction chamber plate facing the flue gas chamber plate, the groove and the flue gas chamber plate cooperating to form a flow channel for methanol working fluid to flow from a first input end to a first output end; and multiple catalyst beds, each catalyst bed being laid in the groove, such that the flowing methanol working fluid undergoes a reforming or cracking reaction to obtain a mixed gas containing hydrogen products, and exchanges heat with the high-temperature flue gas. The temperature of the multiple catalyst beds gradually decreases along the direction from the first input end to the first output end to match the continuously decreasing flue gas temperature during the waste heat recovery process.

[0007] Embodiments of the present invention also provide a methanol-to-hydrogen reaction system, comprising multiple of the above-described compact waste heat recovery methanol-to-hydrogen reaction devices; an internal combustion engine suitable for introducing high-temperature flue gas into the flue gas chamber plate; a methanol container and preheater suitable for conveying heated methanol working fluid to a first input end; and a hydrogen separation device connected to a first output end, the hydrogen separation device being suitable for purifying a mixture containing hydrogen products.

[0008] The compact waste heat recovery methanol-to-hydrogen reactor and system based on the above embodiments of the present invention achieves efficient conversion of the kinetic waste heat of the high-temperature flue gas into the chemical energy of methanol-to-hydrogen by attaching the flue gas chamber plate and the reaction chamber plate together, allowing heat exchange between the high-temperature flue gas and the methanol reforming or cracking reaction. The heat released from the high-temperature flue gas drives the methanol reforming or cracking reaction, thus improving energy utilization efficiency. Multiple catalyst beds are laid in the grooves of the reaction chamber plate, with a zoned design that gradually reduces the temperature of the catalyst beds along the methanol working fluid flow direction. This avoids catalyst sintering failure caused by the heat generated by the high-temperature flue gas, improving the safety and thermochemical reaction performance of the reactor. Attached Figure Description

[0009] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0010] Figure 1 The schematic diagram illustrates the structure of a flue gas chamber plate according to an embodiment of the present invention;

[0011] Figure 2 The schematic diagram illustrates the structure of a reaction chamber plate according to an embodiment of the present invention;

[0012] Figure 3 A three-dimensional schematic diagram of a reaction chamber plate according to an embodiment of the present invention is shown.

[0013] Figure 4 A schematic diagram of the structure of a methanol-to-hydrogen reactor according to an embodiment of the present invention is shown; and

[0014] Figure 5 The schematic diagram illustrates the structure of a methanol-to-hydrogen reactor according to an embodiment of the present invention.

[0015] [Explanation of Labels in the Attached Image]

[0016] 1-Fluorescence chamber plate;

[0017] 11-Shell;

[0018] 12-Guiding protrusion;

[0019] 13-Smoke chamber;

[0020] 14 - Second input terminal;

[0021] 15 - Second output terminal;

[0022] 16-Methanol working fluid flow holes;

[0023] 17-Reaction product flow holes;

[0024] 2-Reaction chamber plate;

[0025] 21-groove;

[0026] 22 - First input terminal;

[0027] 23 - First output terminal;

[0028] 24-Catalyst bed;

[0029] 241 - First catalyst bed;

[0030] 242 - Second catalyst bed;

[0031] 25-High-temperature flue gas flow hole;

[0032] 26 - Low-temperature flue gas flow holes;

[0033] A - First catalyst;

[0034] B - Second catalyst. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0036] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0037] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0038] When using expressions such as "at least one of A, B, and C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C. Similarly, when using expressions such as "at least one of A, B, or C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C.

[0039] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of the present invention. Throughout the accompanying drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding the present invention.

[0040] In related technologies, methanol-to-hydrogen production is often driven by external combustion or waste heat recovery. Heat transfer oil is typically used as the circulating heat medium, first transferring heat to the oil, which is then fed into a fixed-bed reactor to drive the chemical hydrogen production reaction. However, this process adds a flue gas-heat transfer oil heat exchange process, requiring additional heat transfer oil circulation, expansion, and storage devices, resulting in a complex hydrogen production system and increased resource consumption. Furthermore, the high-temperature flue gas-heat transfer oil heat exchange causes heat loss and energy loss to the waste heat, hindering efficient recovery of waste heat. In addition, in existing technologies, catalyst particle-packed beds tend to create significant bed resistance and temperature differences, leading to low catalytic activity in some areas and catalyst deactivation due to overheating in high-temperature regions, reducing catalyst utilization and lifespan.

[0041] In realizing the concept of this invention, it was discovered that to solve the above-mentioned problems, the flue gas chamber plate and the reaction chamber plate are sealed and bonded together to form a methanol-to-hydrogen reactor unit. This achieves efficient heat exchange between the high-temperature flue gas and the methanol-to-hydrogen reaction, simplifying the structure of the reaction device and reducing heat and energy loss. This invention integrates the methanol-to-hydrogen reactor unit into a compact reactor, making the entire reaction device smaller and lighter, with faster reaction start-up and response times. However, since the temperature of the high-temperature flue gas is mostly between 400 and 500°C or higher, while the reaction temperature range for methanol reforming or cracking to produce hydrogen is usually lower than that of the high-temperature flue gas, the catalyst used is prone to sintering and failure, thereby reducing the efficiency of methanol-to-hydrogen production and wasting catalyst.

[0042] Furthermore, in order to solve the above problems, the catalyst bed is designed in a partitioned manner, so that the applicable temperature of different catalyst beds gradually decreases along the flow direction of high-temperature flue gas, thereby reducing problems such as catalyst sintering failure and improving hydrogen production efficiency.

[0043] Therefore, this invention forms a compact reactor by sealing the flue gas chamber plate and the reaction chamber plate together, which improves the heat exchange efficiency between high-temperature flue gas and methanol-to-hydrogen production and saves the volume of the reaction device. By partitioning the catalyst bed, the sintering of the catalyst under the influence of high-temperature flue gas is reduced, improving the safety and thermochemical reaction performance of the entire reaction device, thereby increasing the hydrogen yield and energy utilization efficiency of the entire reaction device.

[0044] Figure 1 The schematic diagram illustrates the structure of a flue gas chamber plate according to an embodiment of the present invention. Figure 2 The schematic diagram illustrates the structure of a reaction chamber plate according to an embodiment of the present invention. Figure 3 A three-dimensional schematic diagram of a reaction chamber plate according to an embodiment of the present invention is shown. Figure 4 The schematic diagram illustrates the structure of a methanol-to-hydrogen reactor according to an embodiment of the present invention.

[0045] The following combination Figures 1-4 A compact waste heat recovery methanol-to-hydrogen reactor according to an embodiment of the present invention will be described in detail.

[0046] like Figures 1-4 As shown, the compact waste heat recovery methanol-to-hydrogen reactor provided in the embodiments of the present invention includes multiple stacked methanol-to-hydrogen reactors. Specifically, each methanol-to-hydrogen reactor includes a flue gas chamber plate 1, a reaction chamber plate 2, and multiple catalyst beds 24.

[0047] The flue gas chamber plate 1 is a closed structural unit made of high-temperature resistant material. The high-temperature resistant material used is stable, does not react with high-temperature flue gas, and can withstand the thermal stress caused by temperatures above 500°C. For example, different metals can be selected as needed, preferably 304 stainless steel. A flow channel suitable for conveying high-temperature flue gas is formed inside the flue gas chamber plate 1.

[0048] The reaction chamber plate 2 is a structural unit made of a high-temperature resistant material. This material is stable, does not react with the methanol working fluid, and can withstand thermal stress from temperatures above 500°C. For example, different metals can be selected as needed, with 304 stainless steel being preferred. The material of the reaction chamber plate 2 can be the same as or different from that of the flue gas chamber plate. A groove 21 is formed on the surface of the reaction chamber plate 2 facing the flue gas chamber plate 1. The reaction chamber plate 2 and the flue gas chamber plate 1 are tightly fitted together, so that the groove 21 forms a sealed space, providing a flow channel for the methanol working fluid to flow from the first input end 22 to the first output end 23.

[0049] Multiple catalyst beds 24 are laid within the groove 21, allowing the flowing methanol working fluid to undergo reforming or cracking reactions to produce a hydrogen-containing mixture, which also exchanges heat with the high-temperature flue gas. Along the direction from the first input end 22 to the first output end 23, the temperature of the multiple catalyst beds 24 gradually decreases to match the continuously decreasing flue gas temperature during waste heat recovery.

[0050] Specifically, the high-temperature flue gas flows through the flue gas chamber plate 1, transferring heat to the methanol working medium in the reaction chamber plate 2, thereby reducing the temperature of the high-temperature flue gas and achieving efficient utilization of the heat in the high-temperature flue gas. The heat-exchanged methanol working medium undergoes a reforming or cracking reaction (strongly endothermic) under catalysis in the catalyst bed 24, producing a mixed gas containing hydrogen products, such as hydrogen products, carbon dioxide, carbon monoxide, and unreacted methanol working medium.

[0051] According to some embodiments of the present invention, a compact plate-type methanol-to-hydrogen reactor is formed by sealing and bonding the reaction chamber plate 2 and the flue gas chamber plate 1 together. Compared with a tubular reactor, it occupies less volume, is lighter, and has a simpler structure. It has faster start-up and response times and is effectively suitable for high-temperature flue gas waste heat recovery applications with frequent changes. It achieves efficient conversion of power exhaust waste heat into hydrogen fuel chemical energy, improving the hydrogen production rate and energy utilization efficiency of the methanol-to-hydrogen reactor. Furthermore, the present invention uses a partitioned design for the catalyst bed, causing the temperature of the catalyst bed to gradually decrease in the direction of high-temperature flue gas flow. This reduces the problem of catalyst sintering failure that may be caused by high-temperature flue gas, effectively improving the safety performance and reaction efficiency of the entire reactor. In addition, the plates of the compact plate-type waste heat recovery methanol-to-hydrogen reactor used in this invention are easy to disassemble, facilitating cleaning and maintenance, and promoting large-scale deployment.

[0052] In one embodiment, the plurality of catalyst beds 24 include: a first catalyst bed 241 and a second catalyst bed 242. The first catalyst bed 241 is configured as a foamed metal skeleton structure, filled with a first catalyst A, to enhance heat and mass transfer performance and support the first catalyst A, preventing the first catalyst bed 241 from collapsing. Specifically, the first catalyst bed 241 includes a foamed metal skeleton, pores, and a metal mesh. The foamed metal skeleton serves as a carrier, containing three-dimensional irregular pores. The first catalyst A is filled into the skeleton surface and pores. A metal mesh serves as an outer protective layer covering the outer wall of the foamed metal skeleton to prevent the first catalyst A from falling off. The metal mesh can be, for example, a metal wire mesh or a sieve plate.

[0053] The second catalyst bed 242 is constructed as a foamed metal skeleton structure, filled with the second catalyst B, to enhance heat and mass transfer performance and support the second catalyst B, preventing the second catalyst bed 242 from collapsing. The structure of the second catalyst bed 242 is largely the same as that of the first catalyst bed 241, the difference being that the second catalyst bed 242 is suitable for filling the second catalyst B, which will not be elaborated further here. Constructing the catalyst bed 24 into a modular foamed metal skeleton structure results in structural stability, better mass and heat transfer performance, higher strength, and more uniform temperature distribution.

[0054] Specifically, the preparation process of the first catalyst bed 241 or the second catalyst bed 242 is as follows: For example, a foamed metal with a certain geometric structure, porosity, and pore size can be used as the catalyst skeleton, and its geometric structure can be, for example, a cuboid. The skeleton is then washed with water and dried. A catalyst slurry is loaded onto the surface of the metal skeleton, and the first catalyst A and / or the second catalyst B are filled into the pores of the foamed metal skeleton. A metal mesh or sieve plate is used as an outer protective layer to cover the outer wall of the foamed metal skeleton. The encapsulated catalyst is then calcined, and after cooling, the catalyst bed 24 is formed.

[0055] More specifically, after the multiple catalyst beds 24 are prepared, they are arranged periodically and respectively housed in the grooves 21 of the reaction chamber plate 2.

[0056] According to some embodiments of the present invention, a first catalyst bed 241 is disposed near the first input end 22. After the methanol working medium is input from the first input end 22, it enters the first catalyst bed 241 and exchanges heat with the high-temperature flue gas in the flue gas chamber plate 1, thereby cooling the high-temperature flue gas. Under the catalytic action of the first catalyst A, the methanol working medium undergoes a reforming or cracking reaction. A second catalyst bed 242 is disposed downstream of the first catalyst bed 241 along the direction from the first input end 22 to the first output end 23. The remaining methanol working medium exchanges heat with the cooled high-temperature flue gas in the second catalyst bed 242, and under the catalytic action of the second catalyst B, the methanol working medium undergoes a reforming or cracking reaction. The heat resistance temperature of the first catalyst A is higher than that of the second catalyst B. Specifically, the first catalyst has higher resistance to sintering and higher high-temperature performance than the second catalyst B, and the second catalyst B has higher catalytic activity and selectivity at low temperatures than the first catalyst A. A first catalyst bed 241 is arranged in the region where the heat exchange temperature between the high-temperature flue gas and the methanol working fluid is relatively high. A first catalyst A with relatively high temperature tolerance and a corresponding foamed metal support is used. A second catalyst bed 242 is set downstream of the first catalyst bed 242, and a second catalyst B with relatively low temperature tolerance and high low-temperature catalytic activity and a corresponding foamed metal support is used. The catalyst bed 24 is arranged in a partitioned manner along the flow direction of the high-temperature flue gas, which further avoids the catalyst sintering failure problem that may be caused by high-temperature flue gas, and more effectively improves the safety of the reactor operation and the thermochemical reaction performance.

[0057] Preferably, the first catalyst A comprises a high-temperature resistant and sintering-resistant catalyst, such as a nickel-based catalyst. The second catalyst B comprises a low-temperature highly catalytically active catalyst, such as a copper-based catalyst. The temperature of high-temperature flue gas can typically reach 400-500°C or even higher, while the optimal reaction temperature for methanol reforming or cracking to produce hydrogen is around 230-280°C. During the experiments related to this invention, it was found that if the waste heat of the high-temperature flue gas is directly used to drive methanol-to-hydrogen production, the temperature of the high-temperature flue gas may be much higher than the optimal temperature for methanol-to-hydrogen production, and the temperature of the high-temperature flue gas gradually decreases as heat exchange occurs. By setting the catalyst bed in 24 zones, efficient heat exchange of the flue gas, temperature uniformity of the catalytic reaction bed, and high reaction efficiency can be achieved simultaneously.

[0058] Furthermore, during the experiment, it was found that when using nickel-based catalysts (main active components such as NiO), the heat resistance temperature is high, and they also have the ability to catalyze methanol reforming / cracking. However, at relatively low temperatures, the catalytic activity and selectivity of nickel-based catalysts for methanol-to-hydrogen conversion are poor. When the high-temperature flue gas is cooled to below 300°C after heat exchange, copper-based (CuO / ZnO / Al2O3) catalysts exhibit better catalytic activity and selectivity for methanol-to-hydrogen conversion. Therefore, this invention partitions the first catalyst bed 241 and the second catalyst bed 242, that is, the first catalyst bed 241 is filled with a nickel-based catalyst, and the second catalyst bed 242 is filled with a copper-based catalyst, forming catalyst beds 24 with different foam metal skeletons. Preferably, the multiple catalyst beds 24 are two catalyst beds 24, namely, the first catalyst bed 241 located along the direction from the first input end 22 to the first output end 23, and the second catalyst bed 242 located downstream of it.

[0059] For example, the first catalyst bed 241 may be based on a nickel foam framework, with nickel oxide, aluminum oxide, or cerium oxide supported. The specific type of supported metal can be selected according to actual needs. The second catalyst bed may be based on a copper foam framework, with CuO / ZnO / Al2O3 catalyst supported. When the catalysts used in the first catalyst bed 241 and the second catalyst bed 242 are the above-mentioned catalysts, their catalytic activity for methanol reforming or cracking reactions is relatively higher, the catalytic effect is better, the hydrogen yield is higher, and they have better heat and mass transfer capabilities. Furthermore, by fixing the first catalyst A and the second catalyst B respectively, the unit volume processing capacity and operational safety of the first catalyst bed 241 and / or the second catalyst bed 242 are improved.

[0060] In some specific embodiments, when the high-temperature flue gas flow rate is within the range of 50 kg / h, the length of the first catalyst bed 241 in the direction from the first input end 22 to the first output end 23 can be designed to be 0.2~0.3 m, for example, 0.2 m, 0.25 m, or 0.3 m. The width of the first catalyst bed 241 in the direction perpendicular to the first input end 22 to the first output end 23 is 0.15~0.25 m, for example, 0.15 m, 0.2 m, or 0.25 m. The thickness of the first catalyst bed 241 is 1~2 cm, for example, 1 cm, 1.5 cm, or 2 cm. The length of the second catalyst bed 242 in the direction from the first input end 22 to the first output end 23 is 0.2~0.3 m, for example, 0.2 m, 0.25 m, or 0.3 m. The width of the second catalyst bed 242 in the direction perpendicular to the first input end 22 to the first output end 23 is 0.15~0.25m, for example, 0.15m, 0.2m or 0.25m. The thickness of the second catalyst bed 242 is 1~2cm, for example, 1cm, 1.5cm or 2cm. By setting the first catalyst bed 241 and the second catalyst bed 242 to the above-mentioned size range, it is possible to ensure efficient heat exchange between the high-temperature flue gas and the methanol-to-hydrogen reaction, while also allowing sufficient heat exchange between the high-temperature flue gas and the first catalyst bed 241. This ensures that when exchanging heat with the methanol working medium in the second catalyst bed, the temperature of the high-temperature flue gas remains below 300℃, thereby preventing the sintering failure of the second catalyst B, thus improving the efficiency of hydrogen production and enhancing the thermochemical reaction performance.

[0061] In some specific implementations, when there is a greater demand for high-temperature flue gas treatment, such as when the flow rate is greater than 50 kg / h, the size of the methanol-to-hydrogen reactor unit can be increased and the number of stacked methanol-to-hydrogen reactor units can be adjusted as needed to meet higher demands for high-temperature flue gas treatment.

[0062] According to some embodiments of the present invention, the flue gas chamber plate 1 includes: a closed shell 11, a plurality of guide protrusions 12, and a flue gas chamber 13. Each guide protrusion 12 extends parallel and interlaced from the shell 11 into the flue gas chamber 13 to form a deflection space for the flow of high-temperature flue gas. By designing the deflection space, the heat exchange efficiency between the flue gas chamber 1 and the reaction chamber plate 2 and the preheating utilization rate of the flue gas chamber 1 are effectively improved, which can significantly reduce the temperature of the discharged high-temperature flue gas, and help to achieve efficient conversion of power waste heat into hydrogen fuel chemical energy, thereby improving energy utilization efficiency.

[0063] According to some embodiments of the present invention, the flue gas chamber plate 1 further includes a second input terminal 14 and a second output terminal 15 located on the same side as the first input terminal 22 and the first output terminal 23, respectively; the flue gas chamber 13 is adapted to allow the high-temperature flue gas introduced through the second input terminal 14 to exchange heat with the methanol working fluid of the reaction chamber plate 2, so that the high-temperature flue gas cooled after heat exchange is output from the second output terminal 15.

[0064] According to some embodiments of the present invention, the flue gas chamber plate 1 further includes methanol working fluid flow holes 16 and reaction product flow holes 17. The reaction chamber plate 2 further includes high-temperature flue gas flow holes 25 and low-temperature flue gas flow holes 26. Figure 5 A schematic diagram of a methanol-to-hydrogen reactor according to an embodiment of the present invention is shown. Figure 5 As shown, when multiple methanol-to-hydrogen reactor units are stacked, please refer to the following: Figure 1 , Figure 2 and Figure 4 As shown, high-temperature flue gas is introduced into the second input terminal 14, with a small portion flowing into the flue gas chamber 13, such as... Figure 2 As shown by the solid arrows and dashed lines, under the influence of the guide protrusion 12, the flue gas flows along the deflection space to the second output end 15. The high-temperature flue gas transfers heat to the stacked reaction chamber plates 1 on both sides, and its temperature drops significantly. Then, it flows out through the low-temperature flue gas flow holes 26 of the reaction chamber plate 1. Most of it continues to flow into the next methanol-to-hydrogen reactor unit through the high-temperature flue gas flow holes 25 of the reaction chamber plate 2. Taking the flow direction consistent with the solid arrows of the high-temperature flue gas as an example, the methanol working medium flows through the methanol working medium flow hole 16 through the first flue gas chamber plate 1. Most of the methanol working medium flows to the next methanol-to-hydrogen reactor unit, and a small portion of the methanol working medium flows into the first catalyst bed 241 from the first input end 22. After a strong endothermic chemical reaction, the chamber temperature drops. The remaining methanol flows through the second catalyst bed 242 in the latter half to continue the methanol reforming or cracking reaction, obtaining a mixture of hydrogen products, carbon dioxide, carbon monoxide, and unreacted methanol working medium. This mixture flows out of the reaction chamber plate 2 from the first output end 23 and flows into the next methanol-to-hydrogen reactor unit through the reaction product flow hole 17.

[0065] Figure 5 A schematic diagram of a methanol-to-hydrogen reactor according to an embodiment of the present invention is shown. Figure 5As shown, the first input end 22 and the first output end 23 of multiple methanol-to-hydrogen reactor units are aligned and connected with the methanol working fluid flow hole 16 and the reaction product flow hole 17 respectively in the stacking direction. The second input end 14 and the second output end 15 are aligned and connected with the high-temperature flue gas flow hole 25 and the low-temperature flue gas flow hole 26 respectively in the stacking direction, forming a sufficient heat exchange between the high-temperature flue gas and the methanol working fluid. By modularizing and expanding the flue gas chamber plate 1 and the reaction chamber plate 2 of the methanol-to-hydrogen reactor, it is possible to expand or reconfigure according to the waste heat recovery requirements. By stacking and integrating the methanol-to-hydrogen reactor units, the reaction scale can be increased, making it suitable for different operating conditions. Furthermore, the plate design facilitates installation, disassembly, and maintenance. By changing the inlet position of the flue gas chamber plate 1 and the reaction chamber plate 2, the flow direction of the high-temperature flue gas can be set and switched to be co-current with the flow direction of the methanol working fluid, or counter-current with different flow directions, to meet different practical application requirements. By adopting the different configuration methods described above, the heat exchange effect and unit volume processing capacity of the methanol-to-hydrogen reactor can be improved more effectively. This is conducive to the rational matching of the cavity structure of the plates and the appropriate temperature of the catalyst, thereby giving full play to the advantages of the partitioned catalyst configuration. It can make full use of the heat provided by the high-temperature flue gas and realize the direct driving of methanol thermochemical production of hydrogen by compact power exhaust waste heat.

[0066] According to some embodiments of the present invention, the working medium is methanol or a mixture of methanol and water vapor. The heat resistance temperature of the first catalyst A is below 500°C, for example, it can be 400°C, 450°C, or 500°C. The heat resistance temperature of the second catalyst B is below 300°C, for example, it can be 200°C, 250°C, or 300°C. By separately setting the first catalyst A and the second catalyst B, the high-temperature resistance and anti-sintering ability of the first catalyst A in the high-temperature region are fully utilized, and the better reactivity and selectivity of the second catalyst B in the medium- and low-temperature region are also utilized.

[0067] According to some embodiments of the present invention, the volume ratio of the first catalyst bed 241 and the second catalyst bed 242 is 3:7 to 1:1, for example, it can be 3:7, 4:6 or 5:5, etc. By designing the volumes of the first catalyst bed 241 and the second catalyst bed 242 in a partitioned modular manner, it is helpful to improve the safety and thermochemical reaction performance of the device.

[0068] According to some embodiments of the present invention, the temperature of the high-temperature flue gas introduced is 400~500°C, for example, 400°C, 420°C, 440°C, 460°C, 480°C, or 500°C, preferably 460°C. Setting the temperature of the high-temperature flue gas within this range helps maintain the heat exchange temperature of the methanol working medium below 300°C when it flows into the second catalyst bed 242, thus preventing sintering failure of the second catalyst B and maintaining its high catalytic activity. The mass flow rate ratio of the high-temperature flue gas to the methanol working medium introduced is 5~30, for example, 5, 10, 15, 20, 25, or 30. Setting the mass flow rate ratio of the two within the above range allows for full utilization of the high-temperature flue gas while helping to maintain a high methanol conversion rate.

[0069] Embodiments of the present invention also provide a methanol-to-hydrogen reaction system, comprising multiple compact waste heat recovery methanol-to-hydrogen reaction devices as described above, an internal combustion engine, a preheater, a methanol container, and a hydrogen separation device. The internal combustion engine is suitable for introducing high-temperature flue gas into the flue gas chamber plate 1. The methanol container and preheater are used in conjunction to supply heated methanol working fluid to the first input terminal 22. The hydrogen separation device is connected to the first output terminal 23 and is suitable for purifying the mixed gas containing hydrogen products.

[0070] According to some embodiments of the present invention, high-temperature flue gas generated by an internal combustion engine is introduced into the flue gas chamber plate 1 through the second input end 14 of the uppermost methanol-to-hydrogen reactor. The methanol working medium from the methanol container is introduced into the reaction chamber plate 2 through the first input end 22. The high-temperature flue gas exchanges heat with the methanol working medium, causing the methanol working medium to undergo a reforming or cracking reaction to produce hydrogen, resulting in a mixed gas containing hydrogen products. The mixed gas flows through the first output end 23 of each reaction chamber plate 2, through the reaction product flow holes 17 of the flue gas chamber plate 1, and into the next methanol-to-hydrogen reactor unit. All the mixed gases obtained from the reaction chamber plates 2 are collected at the first output end 23 of the lowermost methanol-to-hydrogen reactor and introduced into a hydrogen separation device to purify the hydrogen. Multiple methanol-to-hydrogen reactor units can be expanded or reconfigured according to actual application requirements and waste heat recovery needs. Using the methanol-to-hydrogen reaction system of the present invention helps to improve the heat exchange effect and unit volume processing capacity of the methanol-to-hydrogen reactor unit, and by matching a suitable catalyst, the advantages of a compact reactor can be fully utilized. By partitioning the catalyst, the catalytic activity and reaction efficiency of methanol-to-hydrogen are ensured while avoiding catalyst sintering and failure. The reaction system of this invention effectively reduces the temperature of high-temperature flue gas while enabling compact, direct-drive thermochemical hydrogen production from methanol using waste heat from exhaust gas.

[0071] In one specific embodiment, a single-unit methanol-to-hydrogen reactor is used. Both the flue gas chamber plate and the reaction chamber plate are made of 304 stainless steel. The high-temperature flue gas introduced into the flue gas chamber plate has a flow rate of 20 kg / h at the inlet and a temperature of 460°C, and a flow rate of 20 kg / h at the outlet and a temperature of 323.8°C. The methanol introduced has a flow rate of 30 L / min at the inlet and a temperature of 220°C, and a flow rate of 2.57 L / min at the outlet and a temperature of 294.46°C.

[0072] The first catalyst bed used was a nickel foam skeleton supporting cerium oxide and other catalysts, with a metal wire mesh covering the surface of the nickel foam for fixation. After calcination and cooling, a nickel-based catalyst bed with dimensions of 0.25m × 0.2m × 0.01m was obtained. The second catalyst bed used was a copper foam skeleton supporting CuO / ZnO / Al₂O₃, with a metal wire mesh covering the surface of the copper foam for fixation. After calcination and cooling, a copper-based catalyst bed with dimensions of 0.25m × 0.2m × 0.01m was obtained.

[0073] The groove in the reaction chamber plate is like Figure 2 As shown, it contains nickel-based catalyst beds and copper-based catalyst beds that are bonded together on both sides. The collected mixed gas, after purification, yields hydrogen with a production rate of 266.27 kg / (m³). 3 ·h 1 The conversion rate of methanol is approximately 91.46%.

[0074] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of the invention is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A compact waste heat recovery methanol-to-hydrogen reactor, comprising multiple stacked methanol-to-hydrogen reactor units, each of the methanol-to-hydrogen reactor units comprising: Flue gas chamber plate (1), wherein a flow channel suitable for conveying high-temperature flue gas is formed inside the flue gas chamber plate (1); The reaction chamber plate (2) is sealed and fitted to the flue gas chamber plate (1). A groove (21) is formed on the surface of the reaction chamber plate (2) facing the flue gas chamber plate (1). The groove (21) and the flue gas chamber plate (1) cooperate to form a flow channel for methanol working fluid to flow from the first input end (22) to the first output end (23); and Multiple catalyst beds (24) are laid in the groove (21), so that the flowing methanol working fluid undergoes a reforming or cracking reaction to obtain a mixed gas containing hydrogen products, and exchanges heat with the high-temperature flue gas. In the direction from the first input end (22) to the first output end (23), the temperature of the multiple catalyst beds (24) gradually decreases to match the continuously decreasing flue gas temperature during the waste heat recovery process.

2. The compact waste heat recovery methanol-to-hydrogen reactor according to claim 1, wherein, The plurality of catalyst beds (24) include: The first catalyst bed (241) is constructed as a foam metal skeleton structure, filled with the first catalyst (A), to enhance the heat and mass transfer performance and support the first catalyst (A) particles, so as to prevent the first catalyst bed (241) from collapsing. The second catalyst bed (242) is constructed as a foam metal skeleton structure, filled with the second catalyst (B), to enhance the heat and mass transfer performance and support the particles of the second catalyst (B) to prevent the second catalyst bed (242) from collapsing.

3. The compact waste heat recovery methanol-to-hydrogen reactor according to claim 2, wherein, The first catalyst bed (241) is located on the side close to the first input end (22). After the methanol working medium is input from the first input end (22), it enters the first catalyst bed (241) and exchanges heat with the high temperature flue gas of the flue gas chamber plate (1) to cool down the high temperature flue gas. Under the catalytic action of the first catalyst (A), the methanol working medium undergoes a reforming or cracking reaction. The second catalyst bed (242) is located downstream of the first catalyst bed (241) along the direction from the first input end (22) to the first output end (23). The remaining methanol working medium exchanges heat with the cooled high-temperature flue gas in the second catalyst bed (242). Under the catalytic action of the second catalyst (B), the methanol working medium undergoes a reforming or cracking reaction.

4. The compact waste heat recovery methanol-to-hydrogen reactor according to claim 2, wherein, The heat resistance temperature of the first catalyst (A) is higher than that of the second catalyst (B); Preferably, the first catalyst (A) comprises an anti-sintering catalyst, such as a nickel-based catalyst; and the second catalyst (B) comprises a copper-based catalyst.

5. The compact waste heat recovery methanol-to-hydrogen reactor according to claim 1, wherein, The flue gas chamber plate (1) includes: Enclosed shell (11); Multiple guide protrusions (12) extend parallel and interlaced from the housing (11) into the flue gas chamber (13) to form a deflection space for the flow of the high-temperature flue gas.

6. The compact waste heat recovery methanol-to-hydrogen reactor according to claim 5, wherein, The flue gas chamber plate (1) also includes a second input terminal (14) and a second output terminal (15) located on the same side as the first input terminal (22) and the first output terminal (23), respectively. The flue gas chamber (13) is adapted to allow the high-temperature flue gas introduced through the second input end (14) to exchange heat with the methanol working medium of the reaction chamber plate (2), so that the high-temperature flue gas cooled after heat exchange is output from the second output end (15).

7. The compact waste heat recovery methanol-to-hydrogen reactor according to claim 2, wherein, The working medium is methanol or a mixture of methanol and water vapor; The heat resistance temperature of the first catalyst bed (241) is below 500℃; The heat resistance temperature of the second catalyst bed (242) is below 300℃.

8. The compact waste heat recovery methanol-to-hydrogen reactor according to claim 2, wherein, The volume ratio of the first catalyst bed (241) to the second catalyst bed (242) is 3:7 to 1:

1.

9. The compact waste heat recovery methanol-to-hydrogen reactor according to claim 1, wherein, The temperature of the high-temperature flue gas is 400~500℃, and the mass flow ratio of the high-temperature flue gas to the methanol working medium is 5~30.

10. A methanol-to-hydrogen reaction system, comprising a plurality of compact waste heat recovery methanol-to-hydrogen reaction devices as described in any one of claims 1 to 9; An internal combustion engine suitable for introducing the high-temperature flue gas into the flue gas chamber plate (1); A methanol container and preheater, suitable for supplying heated methanol working fluid to the first input terminal; as well as A hydrogen separation device is connected to the first output end (23), and the hydrogen separation device is suitable for purifying the mixed gas containing hydrogen products.

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