A fuel cell system based on multiple fuels

Abstract

The present application relates to the technical field of fuel cell, in particular to a kind of fuel cell system based on multiple fuels.It includes fuel tank, plasma catalytic reforming reactor, low-temperature water-gas shift reactor, first heat exchanger, second heat exchanger, high-temperature water-gas shift reactor, third heat exchanger and high-temperature proton exchange membrane fuel cell stack, wherein the top of plasma catalytic reforming reactor is connected with fuel tank, the bottom is sequentially connected with first heat exchanger, high-temperature water-gas shift reactor, second heat exchanger and low-temperature water-gas shift reactor through pipeline, the product outlet of low-temperature water-gas shift reactor is sequentially connected with second heat exchanger and high-temperature proton exchange membrane fuel cell stack through pipeline, and third heat exchanger is connected with high-temperature proton exchange membrane fuel cell stack in parallel.The present application can realize efficient power generation of multiple fuels in the same fuel cell system.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a fuel cell system based on multiple fuels. Background Technology

[0002] Hydrogen is the optimal fuel for fuel cells, but hydrogen storage and transportation remain challenges. Developing high-temperature proton exchange membrane fuel cell technology based on multi-fuel reforming for hydrogen production holds broad application prospects. It is compatible with existing fuel supply systems such as gasoline and diesel, and can utilize renewable fuels like methanol, ethanol, and methane as feedstock. This type of fuel cell system faces challenges such as a wide temperature range for components, varying waste heat under different fuels, and rapid system start-up. These issues affect the operation and energy conversion efficiency of the system, and even determine its usability. Addressing these problems requires comprehensive design and optimization from system processes to components. However, research on multi-fuel fuel cell technology is still in its early stages, and no systematic and comprehensive solutions to these problems have been reported to date. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide a fuel cell system based on multiple fuels, so as to achieve efficient power generation of multiple fuels in the same fuel cell system.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A fuel cell system based on multiple fuels includes a fuel tank, a plasma catalytic reforming reactor, a water-gas shift reaction device, a third heat exchanger, and a high-temperature proton exchange membrane fuel cell stack. The top of the plasma catalytic reforming reactor is connected to the fuel tank, and the bottom is connected to the water-gas shift reaction device via a pipeline. The water-gas shift reaction device is connected to the high-temperature proton exchange membrane fuel cell stack and the third heat exchanger.

[0006] The water-gas shift reaction device includes a first heat exchanger, a high-temperature water-gas shift reactor, a second heat exchanger, and a low-temperature water-gas shift reactor connected in sequence via pipelines. The first heat exchanger is connected to the bottom of the plasma catalytic reforming reactor. The product outlet of the low-temperature water-gas shift reactor is connected in sequence via pipelines to the second heat exchanger and the high-temperature proton exchange membrane fuel cell stack. The third heat exchanger is connected in parallel with the high-temperature proton exchange membrane fuel cell stack.

[0007] The plasma catalytic reforming reactor includes a sealed container with a fuel inlet and an air inlet at the top and a product outlet at the bottom. A plasma generating device is located in the middle of the sealed container, and a central feed inlet is located on the side wall of the sealed container above the plasma generating device. The fuel inlet is connected to the fuel tank via a pipeline and a fuel pump, and the product outlet is connected to the first heat exchanger.

[0008] The first heat exchanger is a two-layer plate-fin heat exchanger. The upper inlet is connected to the lower product outlet of the plasma catalytic reforming reactor, and the upper outlet is connected to the feed inlet of the high-temperature water-gas shift reactor. The lower layer of the first heat exchanger is a feed cold stream preheating layer. The lower inlet is connected to the second heat exchanger, and the lower outlet is connected to the middle feed inlet of the plasma catalytic reforming reactor. The lower layer of the first heat exchanger is provided with a liquid feed inlet, which is connected to a liquid water feed pump.

[0009] The high-temperature water-gas shift reactor is a closed container with a lower feed inlet and an upper discharge outlet. The lower feed inlet of the high-temperature water-gas shift reactor is connected to the upper outlet of the first heat exchanger, and the upper discharge outlet is connected to the second heat exchanger. A water inlet is provided on the lower side wall of the high-temperature water-gas shift reactor. The high-temperature water-gas shift reactor contains a high-temperature shift catalyst.

[0010] The outer wall of the high-temperature water-gas shift reactor is provided with a cooling jacket for passing a cold material, which is air. The cooling jacket has an inlet and an outlet. The inlet of the cooling jacket is connected to an air pump II, and the outlet of the cooling jacket is connected to the middle inlet of the plasma catalytic reforming reactor.

[0011] The second heat exchanger is a plate-fin heat exchanger with four layers, which are the first to the fourth layers from right to left. The feed inlet of the first layer is connected to the upper outlet of the high-temperature water-gas shift reactor, and the outlet of the first layer is connected to the feed inlet of the low-temperature water-gas shift reactor.

[0012] The second-layer feed inlet is connected to the fuel tank via a fuel feed pump, and the second-layer discharge outlet is connected to the lower-layer feed inlet provided on the first heat exchanger.

[0013] The third feed inlet is connected to the outlet of the low-temperature water-gas shift reactor, and the third outlet is connected to the third heat exchanger and the high-temperature proton exchange membrane fuel cell stack via a three-way A.

[0014] The low-temperature water-gas shift reactor is a closed container with an upper inlet and a lower outlet. The upper inlet of the low-temperature water-gas shift reactor is connected to the first outlet of the second heat exchanger via a connecting pipe, and a liquid water feed port is provided on the side wall of the connecting pipe. The lower outlet of the low-temperature water-gas shift reactor is connected to the third inlet of the second heat exchanger. The low-temperature water-gas shift reactor is filled with a catalyst whose active component is platinum and / or copper.

[0015] The high-temperature proton exchange membrane fuel cell stack is provided with an anode inlet, an anode outlet, a cathode inlet, a cathode outlet, a stack heat transfer oil chamber inlet, and a stack heat transfer oil chamber outlet;

[0016] The anode inlet is connected to the tee A, and the anode outlet is connected to the inlet of the catalytic combustion chamber of the third heat exchanger;

[0017] The cathode inlet is connected to air pump IV, and the cathode outlet is vented.

[0018] The third heat exchanger is connected in parallel with the fourth heat exchanger and is connected to the inlet of the electric stack heat transfer oil chamber through a three-way C and to the outlet of the electric stack heat transfer oil chamber through a three-way B.

[0019] A high-level heat transfer oil tank connected to the high-temperature proton exchange membrane fuel cell stack is provided above it.

[0020] The third heat exchanger is a multi-layer heat exchanger, comprising a catalytic combustion chamber, a heat transfer oil chamber, a combustion exhaust gas heat exchange chamber, a first water vaporization chamber, and a second water vaporization chamber. The inlet of the first water vaporization chamber is connected to a second water pump, and the outlet of the first water vaporization chamber is connected to the fourth layer feed inlet of the second heat exchanger. The inlet of the second water vaporization chamber is connected to the first water pump, and the outlet of the second water vaporization chamber is connected to the water feed inlet on the lower side wall of the high-temperature water-gas shift reactor.

[0021] The inlet of the catalytic combustion chamber is connected to a three-way valve A via a valve, and the outlet of the catalytic combustion chamber is connected to the inlet of the combustion exhaust heat exchange chamber; the outlet of the combustion exhaust heat exchange chamber is vented.

[0022] The inlet of the heat transfer oil chamber is connected to tee B via a valve, and the outlet of the heat transfer oil chamber is connected to tee C.

[0023] The fourth heat exchanger is a tube-fin heat exchanger used to cool the heat transfer oil; a fan is installed outside the fins to provide cold air to the heat exchanger.

[0024] The advantages and beneficial effects of this invention are as follows: This invention utilizes plasma catalytic reforming technology to achieve hydrogen production from multiple fuels in the same fuel processor, with a hydrogen dry basis concentration ≥40% and a CO dry basis concentration ≤3%. This hydrogen can be directly used as fuel for high-temperature proton exchange membrane fuel cells, thereby converting the chemical energy of multiple fuels into electrical energy. It is compatible with existing gasoline or diesel fuel supply systems and can use renewable fuels such as methanol, ethanol, and methane as feedstock. Furthermore, because the high-temperature proton exchange membrane fuel cell has high CO tolerance, compared to low-temperature proton exchange membrane fuel cells, there is no need to further remove CO to ppm using selective oxidation, membrane separation, or pressure swing adsorption methods, simplifying the system process. In addition, the use of plasma-assisted spray combustion and catalytic combustion enables rapid system start-up and stable operation.

[0025] This invention utilizes a multi-flow plate-fin heat exchanger to achieve cascade heat exchange of high and low temperature hot and cold streams in the system. This not only improves the system efficiency but also results in a compact structure, low pressure drop, and large heat exchange area. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the structural principle of a fuel cell system based on multiple fuels according to the present invention.

[0027] Figure 2 shows the system discharge performance under different feed conditions in the embodiments of the present invention: (a) shows the system discharge performance under diesel feed; (b) shows the system discharge performance under methanol feed.

[0028] In the diagram: 1-Fuel tank; 2-Fuel pump; 3-Fuel feed pump; 4-Air compressor; 5-Air pump I; 6-Plasma catalytic reforming reactor; 7-Low-temperature water-gas shift reactor; 8-First heat exchanger; 9-Second heat exchanger; 10-Liquid water feed pump; 11-Liquid pump IV; 12-Liquid pump V; 13-High-temperature water-gas shift reactor; 14-Air pump II; 15-First water pump; 16-Third heat exchanger; 17-Second water pump; 18-Air pump III; 19-Fourth heat exchanger; 20-Heat transfer oil circulation pump; 21-Heat transfer oil high-level tank; 22-Air pump IV; 23-High-temperature proton exchange membrane fuel cell stack. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1As shown, the present invention provides a fuel cell system based on multiple fuels, including a fuel tank 1, a plasma catalytic reforming reactor 6, a water-gas shift reaction device, a third heat exchanger 16, and a high-temperature proton exchange membrane fuel cell stack 23. The top of the plasma catalytic reforming reactor 6 is connected to the fuel tank 1, and the bottom is connected to the water-gas shift reaction device through a pipeline. The water-gas shift reaction device is connected to the high-temperature proton exchange membrane fuel cell stack 23 and the third heat exchanger 16 through a pipeline.

[0031] In an embodiment of the present invention, the water-gas shift reaction device includes a first heat exchanger 8, a high-temperature water-gas shift reactor 13, a second heat exchanger 9, and a low-temperature water-gas shift reactor 7 connected in sequence by pipelines. The first heat exchanger 8 is connected to the bottom of the plasma catalytic reforming reactor 6. The product outlet of the low-temperature water-gas shift reactor 7 is connected in sequence by pipelines to the second heat exchanger 9 and the high-temperature proton exchange membrane fuel cell stack 23. The third heat exchanger 16 is connected in parallel with the high-temperature proton exchange membrane fuel cell stack 23.

[0032] In an embodiment of the present invention, the plasma catalytic reforming reactor 6 includes a sealed container with a fuel inlet and an air inlet at the upper part of the sealed container and a product outlet at the lower part of the sealed container; a plasma generating device is provided in the middle of the sealed container, and a central feed inlet is provided on the side wall of the sealed container above the plasma generating device; the fuel inlet is connected to the fuel tank 1 via a pipeline through a fuel pump 2, and the product outlet is connected to the first heat exchanger 8; one air inlet is connected to an air pump I5, and the other air inlet is connected to an air compressor 4.

[0033] Specifically, the plasma catalytic reforming reactor 6 includes an air-assisted atomizing nozzle, a wall-mounted protective gas inlet and distribution chamber, an upper insulating ceramic, an upper electrode, a lower insulating ceramic, a central inlet and distribution structure, a lower electrode, a catalytic reforming chamber, a ceramic fiber insulation tube, a catalyst support plate, and an outlet. The upper electrode is connected to the high-voltage output terminal of a high-voltage power supply, and the lower electrode is grounded. The plasma catalytic reforming reactor 6 consists of two coaxially facing annular electrodes. The mixed gas is evenly distributed through inclined holes on the outer side of the electrodes and enters the space between the electrodes at a tangential velocity, where it is broken down and discharged, generating plasma. In this embodiment,

[0034] Furthermore, a fuel atomizer is installed at the fuel inlet of the plasma catalytic reforming reactor to atomize the liquid fuel. It is equipped with a fuel inlet, an air inlet and an atomized fuel outlet. The atomized fuel outlet is connected to the fuel inlet of the plasma catalytic reforming reactor 6. The fuel inlet is connected to the fuel tank 1 through a pipeline, and the air inlet is connected to the air compressor 4.

[0035] In an embodiment of the present invention, the first heat exchanger 8 is a plate-fin heat exchanger with two layers, i.e., it is composed of two layers of material stacked in a sandwich structure. The upper inlet is connected to the lower product outlet of the plasma catalytic reforming reactor 6, and the upper outlet is connected to the feed inlet of the high-temperature water-gas shift reactor 13. The lower layer of the first heat exchanger 8 is a preheating layer for the cold feed stream, with its inlet connected to the second heat exchanger 9 and its outlet connected to the middle feed inlet of the plasma catalytic reforming reactor 6. The lower layer of the first heat exchanger 8 is provided with a liquid feed inlet, which is connected to a liquid water feed pump 10. The liquid water feed inlet is used to quickly add water to the plasma catalytic reforming reactor 6 during startup to rapidly obtain qualified reformed gas.

[0036] In an embodiment of the present invention, the high-temperature water-gas shift reactor 13 is a closed container with a lower feed inlet at the lower end and an upper discharge outlet at the upper end. The lower feed inlet of the high-temperature water-gas shift reactor 13 is connected to the upper outlet of the first heat exchanger 8, and the upper discharge outlet is connected to the second heat exchanger 9. A water inlet is provided on the lower side wall of the high-temperature water-gas shift reactor 13. The high-temperature water-gas shift reactor 13 is filled with a high-temperature shift catalyst.

[0037] Furthermore, a cooling jacket is provided on the outer wall of the high-temperature water-gas shift reactor 13 for circulating a cold material to remove some of the heat generated in the reactor and preheat the cold material. In this embodiment, the cold material is air. The cooling jacket has an inlet and an outlet. The inlet of the cooling jacket is connected to the air pump II 14, and the outlet of the cooling jacket is connected to the central inlet of the plasma catalytic reforming reactor 6.

[0038] Specifically, the water inlet of the high-temperature water-gas shift reactor 13 is used to add gaseous and / or liquid water, thereby adjusting the temperature of the feed gas and the water-to-carbon ratio; the outlet of the jacket of the high-temperature water-gas shift reactor 13 is connected to the middle inlet of the plasma catalytic reforming reactor 6, thereby ensuring that the fuel, air and water vapor are fully mixed, reducing the residence time of the mixed gas in the front-end pipeline or equipment, and preventing the mixed gas from reacting before entering the plasma zone of the plasma catalytic reforming reactor 6.

[0039] In this embodiment of the invention, the second heat exchanger 9 is a four-layer plate-fin heat exchanger, consisting of four layers of material stacked in a sandwich structure, arranged from right to left as the first to fourth layers. It is used to cool the high- and low-temperature shift outlet gases and preheat the feed. The second heat exchanger 9 is equipped with fins to enhance heat exchange. Specifically, the first layer inlet is connected to the upper outlet of the high-temperature water-gas shift reactor 13, and the first layer outlet is connected to the inlet of the low-temperature water-gas shift reactor 7. The second layer inlet is connected to the fuel tank 1 via the fuel feed pump 3, and the second layer outlet is connected to the lower inlet of the first heat exchanger 8. The third layer inlet is connected to the outlet of the low-temperature water-gas shift reactor 7, and the third layer outlet is connected to the catalytic combustion chamber of the third heat exchanger 16 and the high-temperature proton exchange membrane fuel cell stack 23 via a three-way A. During startup, the reformed gas enters the catalytic combustion chamber of the third heat exchanger 16, combusts, and releases heat, heating the heat transfer oil and subsequently the fuel cell stack. When stable, the reformed gas does not enter the catalytic combustion chamber, but instead enters the anode discharge of the fuel cell stack; the fourth layer is a steam preheating chamber, the feed port of the fourth layer is connected to the water chamber outlet of the third heat exchanger 16, and the discharge port of the fourth layer is connected to the lower inlet of the first heat exchanger 8.

[0040] A gas or liquid distributor is provided at the bottom of the high-temperature water-gas shift reactor 13. The distributor is connected to the water inlet and is used to uniformly distribute the gaseous or liquid water entering the distributor. The active component of the high-temperature shift catalyst is platinum and / or iron.

[0041] In an embodiment of the present invention, the low-temperature water-gas shift reactor 7 is a closed container with an upper inlet and a lower outlet. The upper inlet of the low-temperature water-gas shift reactor 7 is connected to the first outlet of the second heat exchanger 9 via a connecting pipe. A liquid water feed port is provided on the side wall of the connecting pipe for adjusting the gas temperature. The lower outlet of the low-temperature water-gas shift reactor 7 is connected to the third inlet of the second heat exchanger 9. The low-temperature water-gas shift reactor 7 is filled with a catalyst whose active component is platinum and / or copper.

[0042] In an embodiment of the present invention, the high-temperature proton exchange membrane fuel cell stack 23 is provided with an anode inlet, an anode outlet, a cathode inlet, a cathode outlet, a stack heat transfer oil chamber inlet, and a stack heat transfer oil chamber outlet; the anode inlet is connected to a three-way valve A, and the anode outlet is connected to the inlet of the catalytic combustion chamber of the third heat exchanger 16; the cathode inlet is connected to an air pump IV 22, and the cathode outlet is vented; the third heat exchanger 16 and the fourth heat exchanger 19 are connected in parallel, and are connected to the stack heat transfer oil chamber inlet through a three-way valve C, and to the stack heat transfer oil chamber outlet through a three-way valve B, and a heat transfer oil circulation pump 20 is provided at the stack heat transfer oil chamber outlet.

[0043] Furthermore, a high-level heat transfer oil tank 21 is provided above the high-temperature proton exchange membrane fuel cell stack 23 and connected thereto. The high-level heat transfer oil tank 21 is a heat transfer oil storage tank, and the heat transfer oil level in the storage tank is above the stack. The heat transfer oil inlet of the stack is connected to the third and fourth heat exchangers via a three-way valve E and then a three-way valve C. The three-way valve E is connected to the high-level heat transfer oil tank 21 via a valve.

[0044] In an embodiment of the present invention, the third heat exchanger 16 is a multi-layer heat exchanger. Specifically, it is a five-layer plate-fin heat exchanger, consisting of five layers of material stacked in a sandwich structure. From right to left, the sandwich structure consists of a catalytic combustion chamber, a first water vaporization chamber, a catalytic combustion exhaust gas heat exchange chamber, a heat transfer oil chamber, and a second water vaporization chamber. The inlet of the first water vaporization chamber is connected to the second water pump 17, and the outlet of the first water vaporization chamber is connected to the fourth inlet of the second heat exchanger 9. The inlet of the second water vaporization chamber is connected to the first water pump 15, and the outlet of the second water vaporization chamber is connected to the water inlet on the lower side wall of the high-temperature water-gas shift reactor 7. The inlet of the catalytic combustion chamber is connected to a three-way valve A via a valve, and the outlet of the catalytic combustion chamber is connected to the inlet of the combustion exhaust gas heat exchange chamber. The outlet of the combustion exhaust gas heat exchange chamber is vented. The inlet of the heat transfer oil chamber is connected to a three-way valve B via a valve. The three-way valve B is connected to the outlet of the heat transfer oil circulation pump 20, and the outlet of the heat transfer oil chamber is connected to a three-way valve C. The tee C is connected to the inlet of the heat transfer oil chamber of the fuel cell stack and the fluid outlet of the fourth heat exchanger 19. The inlet of the heat transfer oil circulation pump 20 is connected to the heat transfer oil high-level tank 21 via the tee D and a valve.

[0045] In an embodiment of the present invention, the fourth heat exchanger 19 is a tube-fin heat exchanger used to cool the heat transfer oil; a fan is provided outside the fins to provide cold air to the heat exchanger.

[0046] The present invention provides a fuel cell system based on multiple fuels, the working principle of which is as follows:

[0047] The plasma catalytic reforming reactor 6 is used to reform various fuels (such as methane, methanol, ethanol, gasoline, and diesel) into a mixture rich in hydrogen and carbon monoxide. The plasma catalytic reforming reactor 6 consists of three parts: an upper spray feed device, a middle plasma reforming section, and a lower catalytic reforming chamber. High-temperature air, fuel, and water are mixed at the middle inlet of the plasma catalytic reforming reactor 6 (reducing mixing time and preventing carbon buildup and overheating due to reactions before entering the processor) before entering the processor. The high-temperature mixture exiting the plasma catalytic reforming reactor 6 is cooled by the first heat exchanger 8 before entering the high-temperature water-gas shift reactor 13. The first heat exchanger 8 has a two-layer plate-fin structure for heat exchange between the high-temperature mixture and the feed (fuel and water), enhancing the comprehensive utilization of system heat. The high-temperature water-gas shift reactor 13 is equipped with a jacket to cool the high-temperature shift reactor while preheating the feed air. The gas exiting the high-temperature water-gas shift reactor 13 is cooled by the second heat exchanger 9 and then enters the low-temperature water-gas shift reactor 7 to further reduce the carbon monoxide content. The gas exiting the low-temperature water-gas shift reactor 7 is cooled by the second heat exchanger 9 and then enters the third heat exchanger 16 (during startup) for catalytic combustion or for discharge at the anode of the fuel cell stack (during stable operation). The tail gas from the anode of the fuel cell stack is discharged after catalytic combustion in the third heat exchanger 16. The residual heat in the fuel cell stack is carried away by the heat transfer oil. The high-temperature heat transfer oil is cooled by the third heat exchanger 16 and the fourth heat exchanger 19 and then recycled back to the fuel cell stack for reuse.

[0048] Specifically, during system startup, the fuel is first completely combusted. Once the high-temperature variable temperature reaches the active temperature, reforming begins, and the reformed gas is introduced into the fuel chamber of the third heat exchanger 16 for catalytic combustion, heating the heat transfer oil. This heat transfer oil is then introduced into the fuel stack to heat the stack. Once the stack temperature reaches the operating state, stable operation and discharge begin. The stack's operating temperature is between 100-200℃.

[0049] Furthermore, the end plate with the anode inlet of the fuel cell stack is provided with two stacked heat exchange jackets. One layer is used to cool the anode feed, with the inlet connected to the tee A and the outlet connected to the anode inlet pipe inside the fuel cell stack. The other layer preheats the cathode feed air, with the inlet connected to the air pump IV22 and the outlet connected to the cathode inlet pipe inside the fuel cell stack.

[0050] The present invention provides a fuel cell system based on multiple fuels, the operation method of which is as follows:

[0051] When the system is started, first turn on the air pump II14 to introduce air into the feed port in the middle of the plasma catalytic reforming reactor 6, and turn on the high voltage power supply of the plasma catalytic reforming reactor 6 to generate plasma in the middle of the plasma catalytic reforming reactor 6.

[0052] Turn on air pump I5, fuel pump 2 and air compressor 4 to spray feed the processor and preheat the system by complete combustion; when the inlet temperature of high temperature water-gas shift reactor 13 is greater than 350°C, stop spraying and turn off fuel pump 2, air pump I5 and air compressor 4.

[0053] The liquid water feed pump 10 and fuel feed pump 3 are turned on. By adjusting the flow rate of the air compressor 4, reformed gas is generated and introduced into the catalytic combustion chamber of the third heat exchanger 16. The air pump III 18 is turned on to allow the reformed gas to burn and release heat. The heat transfer oil circulation pump 20 is turned on to discharge the heat released from the catalytic combustion chamber to heat the fuel cell stack. After the fuel cell stack reaches the operating temperature, the first water pump 15 and the second water pump 17 are turned on to control the total water-to-carbon ratio between 1.0 and 2.5, generate qualified reformed gas, and switch to discharge into the fuel cell stack. The tail gas from the fuel cell stack anode is introduced into the combustion chamber of the third heat exchanger 16 for catalytic combustion, recovering waste heat and removing combustible gases at the same time.

[0054] Example

[0055] Taking diesel fuel as an example, during system startup, air pump II 14 is first turned on to introduce air into the central feed inlet of the plasma catalytic reforming reactor 6, and the high-voltage power supply is turned on to generate plasma in the central part of the processor. Air pump I 5, fuel pump 2, and air compressor 4 are then turned on to feed diesel fuel at a rate of 8 ml / min, ensuring complete combustion to preheat the system. When the inlet temperature of the high-temperature water-gas shift reactor 13 exceeds 350°C, spraying is stopped, and fuel pump 2, air pump I 5, and air compressor 4 are turned off. Liquid water feed pump 10 is then turned on, with a set flow rate of 13 ml / min. Fuel feed pump 3 is turned on, and the fuel flow rate is set to 25 ml / min. The oxygen-to-carbon ratio is controlled between 0.8 and 1.5 by adjusting the flow rate of air pump II 14 to generate reformed gas. This reformed gas is then introduced into the catalytic combustion chamber of the third heat exchanger 16. Air pump III 18 is turned on, and the flow rate is set to 100–300 L / min to allow the reformed gas to combust and release heat. Heat transfer oil circulation pump 20 is turned on to vent the heat released from the catalytic combustion chamber to heat the fuel cell stack. Under these operating conditions, the fuel cell stack can rise from approximately 20°C to 170°C within 30 minutes. After the fuel cell stack reaches its operating temperature, the first water pump 15 and the second water pump 17 are turned on, controlling the total water-to-carbon ratio between 1.0 and 2.5 to generate qualified reformed gas, which is then switched to fuel cell discharge. The fuel cell stack anode exhaust gas is introduced into the combustion chamber of the third heat exchanger 16 for catalytic combustion, recovering waste heat and removing combustible gases. As the discharge power of the fuel cell stack varies, it may overheat. In this case, the fan of the fourth heat exchanger 19 needs to be turned on, and the flow rate of the heat transfer oil passing through the fourth heat exchanger 19 needs to be adjusted to dissipate heat from the stack and maintain it within a suitable operating temperature range. The discharge performance of the system under different fuel feedstocks is shown in Figure 2. When the system uses diesel and methanol as feedstocks, it outputs 6.5–7 kW of electrical power, realizing the discharge of multiple fuels in the same fuel cell system.

[0056] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, extensions, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A fuel cell system based on multiple fuels, characterized in that, It includes a fuel tank (1), a plasma catalytic reforming reactor (6), a water-gas shift reaction device, a third heat exchanger (16), and a high-temperature proton exchange membrane fuel cell stack (23). The top of the plasma catalytic reforming reactor (6) is connected to the fuel tank (1), and the bottom is connected to the water-gas shift reaction device through a pipeline. The water-gas shift reaction device is connected to the high-temperature proton exchange membrane fuel cell stack (23) and the third heat exchanger (16). The water-gas shift reaction device includes a first heat exchanger (8), a high-temperature water-gas shift reactor (13), a second heat exchanger (9), and a low-temperature water-gas shift reactor (7) connected in sequence by pipelines. The first heat exchanger (8) is connected to the bottom of the plasma catalytic reforming reactor (6). The product outlet of the low-temperature water-gas shift reactor (7) is connected in sequence by pipelines to the second heat exchanger (9) and the high-temperature proton exchange membrane fuel cell stack (23). The third heat exchanger (16) is connected in parallel with the high-temperature proton exchange membrane fuel cell stack (23).

2. The fuel cell system based on multiple fuels according to claim 1, characterized in that, The plasma catalytic reforming reactor (6) includes a sealed container with a fuel inlet and an air inlet at the top and a product outlet at the bottom. A plasma generating device is located in the middle of the sealed container, and a central feed inlet is located on the side wall of the sealed container above the plasma generating device. The fuel inlet is connected to the fuel tank (1) via a pipeline through a fuel pump (2), and the product outlet is connected to the first heat exchanger (8).

3. The fuel cell system based on multiple fuels according to claim 2, characterized in that, The first heat exchanger (8) is a plate-fin heat exchanger with two layers. The upper inlet is connected to the lower product outlet of the plasma catalytic reforming reactor (6), and the upper outlet is connected to the feed inlet of the high-temperature water-gas shift reactor (13). The lower layer of the first heat exchanger (8) is a feed cold flow preheating layer. The lower inlet is connected to the second heat exchanger (9), and the lower outlet is connected to the middle feed inlet of the plasma catalytic reforming reactor (6). The lower layer of the first heat exchanger (8) is provided with a liquid feed inlet, which is connected to a liquid water feed pump (10).

4. The fuel cell system based on multiple fuels according to claim 3, characterized in that, The high-temperature water-gas shift reactor (13) is a closed container with a lower feed inlet and an upper discharge outlet. The lower feed inlet of the high-temperature water-gas shift reactor (13) is connected to the upper outlet of the first heat exchanger (8), and the upper discharge outlet is connected to the second heat exchanger (9). A water inlet is provided on the lower side wall of the high-temperature water-gas shift reactor (13). The high-temperature water-gas shift reactor (13) is filled with a high-temperature shift catalyst.

5. The fuel cell system based on multiple fuels according to claim 4, characterized in that, The outer wall of the high-temperature water-gas shift reactor (13) is provided with a cooling jacket for passing cold material, which is air; the cooling jacket is provided with an inlet and an outlet, the inlet of the cooling jacket is connected to the air pump II (14), and the outlet of the cooling jacket is connected to the middle inlet of the plasma catalytic reforming reactor (6).

6. The fuel cell system based on multiple fuels according to claim 4, characterized in that, The second heat exchanger (9) is a plate-fin heat exchanger with four layers, from right to left, the first to the fourth layers. The feed inlet of the first layer is connected to the upper outlet of the high-temperature water-gas shift reactor (13), and the outlet of the first layer is connected to the feed inlet of the low-temperature water-gas shift reactor (7). The second-layer feed inlet is connected to the fuel tank (1) via the fuel feed pump (3), and the second-layer discharge outlet is connected to the lower-layer feed inlet provided on the first heat exchanger (8). The third feed inlet is connected to the outlet of the low-temperature water-gas shift reactor (7), and the third outlet is connected to the third heat exchanger (16) and the high-temperature proton exchange membrane fuel cell stack (23) via a three-way A.

7. The fuel cell system based on multiple fuels according to claim 6, characterized in that, The low-temperature water-gas shift reactor (7) is a closed container with an upper inlet and a lower outlet. The upper inlet of the low-temperature water-gas shift reactor (7) is connected to the first outlet of the second heat exchanger (9) through a connecting pipe, and a liquid water feed port is provided on the side wall of the connecting pipe. The lower outlet of the low-temperature water-gas shift reactor (7) is connected to the third inlet of the second heat exchanger (9). The low-temperature water-gas shift reactor (7) is filled with a catalyst whose active component is platinum and / or copper.

8. The fuel cell system based on multiple fuels according to claim 6, characterized in that, The high-temperature proton exchange membrane fuel cell stack (23) is provided with an anode inlet, an anode outlet, a cathode inlet, a cathode outlet, a stack heat transfer oil chamber inlet, and a stack heat transfer oil chamber outlet; The anode inlet is connected to the three-way A, and the anode outlet is connected to the inlet of the catalytic combustion chamber of the third heat exchanger (16); The cathode inlet is connected to air pump Ⅳ (22), and the cathode outlet is vented. The third heat exchanger (16) is connected in parallel with the fourth heat exchanger (19), and is connected to the inlet of the electric stack heat transfer oil chamber through a three-way C, and to the outlet of the electric stack heat transfer oil chamber through a three-way B; The high-temperature proton exchange membrane fuel cell stack (23) is provided with a heat transfer oil high-level tank (21) connected to it.

9. The fuel cell system based on multiple fuels according to claim 8, characterized in that, The third heat exchanger (16) is a multi-layer heat exchanger, including a catalytic combustion chamber, a heat transfer oil chamber, a combustion exhaust gas heat exchange chamber, a first water vaporization chamber and a second water vaporization chamber. The inlet of the first water vaporization chamber is connected to the second water pump (17), and the outlet of the first water vaporization chamber is connected to the fourth layer feed port of the second heat exchanger (9). The inlet of the second water vaporization chamber is connected to the first water pump (15), and the outlet of the second water vaporization chamber is connected to the water feed port on the lower side wall of the high-temperature water-gas shift reactor (13). The inlet of the catalytic combustion chamber is connected to a three-way valve A via a valve, and the outlet of the catalytic combustion chamber is connected to the inlet of the combustion exhaust heat exchange chamber; the outlet of the combustion exhaust heat exchange chamber is vented. The inlet of the heat transfer oil chamber is connected to tee B via a valve, and the outlet of the heat transfer oil chamber is connected to tee C.

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