A thermal self-balancing fuel cell power generation system and method

Abstract

The present application discloses a fuel cell power generation system and method with self-heat balance, which relates to the field of fuel cell power generation technology. A fuel cell power generation system with self-heat balance, comprising a hydrogen-rich hydrogen oil storage tank, a dehydrogenation reactor and a hydrogen-poor hydrogen oil storage tank connected in sequence, and also comprising a thermostat, an SOFC stack and an exhaust gas treatment device, wherein the hydrogen end of the dehydrogenation reactor is connected to the thermostat, the thermostat is connected to the SOFC stack, the SOFC stack is connected to the exhaust gas treatment device, the air end of the dehydrogenation reactor is connected to the exhaust gas treatment device, and the exhaust gas end of the exhaust gas treatment device is respectively connected to the thermostat and the dehydrogenation reactor. The system of the present application not only improves the energy utilization efficiency, but also solves the problem of thermal energy demand for LOHC in the application of hydrogen at the end.

Description

Technical Field

[0001] The present application relates to the technical field of fuel cell power generation, and in particular to a fuel cell power generation system and method with self-heat balance. Background Art

[0002] Liquid Organic Hydrogen Carrier (LOHC) technology is a hydrogen storage and transportation technology that "encapsulates" hydrogen in liquid organic compounds through chemical reactions, enabling high-density storage, transportation, and release of hydrogen. LOHC hydrogen applications require external heating, and the dehydrogenation unit must be maintained within the appropriate dehydrogenation temperature range to maximize the technology's effectiveness. Solid Oxide Fuel Cell (SOFC) technology can organically integrate LOHC with other clean energy technologies in hydrogen applications, maximizing energy efficiency. Currently, SOFCs cannot completely react the input anode gas. Therefore, exhaust gas combustion is typically installed. The heat generated by the exhaust combustion can be used to provide a high-temperature operating environment for the SOFC stack and system, while also fully meeting the energy and temperature requirements for dehydrogenation using LOHC technology. However, the existing SOFC power generation system and LOHC hydrogen storage device (dehydrogenation end) are designed to operate independently, and the two are not organically coupled together. As a result, most of the SOFC's high-temperature exhaust gas is directly discharged, resulting in a large amount of high-grade energy being wasted. At the same time, the LOHC's thermal energy requirements and stable temperature environment at the dehydrogenation end cannot be met. Summary of the Invention

[0003] The main purpose of this application is to provide a fuel cell power generation system and method with self-balanced heat, aiming to solve the technical problem in the prior art that the heat energy generated by SOFC power generation is not fully utilized, resulting in energy waste.

[0004] To achieve the above-mentioned objectives, the present application proposes a heat self-balancing fuel cell power generation system, comprising a hydrogen-rich hydrogen oil storage tank, a dehydrogenation reactor and a hydrogen-poor hydrogen oil storage tank connected in sequence, and also comprising a thermostat, an SOFC stack and an exhaust gas treatment device, wherein the hydrogen end of the dehydrogenation reactor is connected to the thermostat, the thermostat is connected to the SOFC stack, the SOFC stack is connected to the exhaust gas treatment device, the air end of the dehydrogenation reactor is connected to the exhaust gas treatment device, and the exhaust gas end of the exhaust gas treatment device is respectively connected to the thermostat and the dehydrogenation reactor.

[0005] Optionally, the system further includes a primary heat exchanger and a secondary heat exchanger, the air inlet end of the primary heat exchanger being connected to the exhaust gas end of the exhaust gas treatment device and an external cold air pipeline, respectively, the exhaust gas end of the primary heat exchanger being connected to the air inlet end of the secondary heat exchanger, the air outlet end of the primary heat exchanger being connected to the thermostat, the air inlet end of the secondary heat exchanger being also connected to an external cold air pipeline, the exhaust gas end of the secondary heat exchanger being connected to the dehydrogenation reactor, and the air outlet end of the secondary heat exchanger being connected to the dehydrogenation reactor and the exhaust gas treatment device, respectively.

[0006] Optionally, the system further includes a first air distribution valve, a second air distribution valve and a third air distribution valve, wherein the first air distribution valve is located on the pipeline between the dehydrogenation reactor and the tail gas treatment device, and the first air distribution valve is used to distribute the air leaving the dehydrogenation reactor to the air inlet end of the tail gas treatment device and the external cold air in real time; the second air distribution valve is located on the pipeline through which the external cold air enters the primary heat exchanger and the secondary heat exchanger, and the second air distribution valve is used to distribute the mixed gas of the external cold air and the air distributed by the first air distribution valve to the primary heat exchanger and the secondary heat exchanger in real time; the third air distribution valve is connected to the air outlet end of the secondary heat exchanger, and the third air distribution valve is used to distribute the air that has passed through the secondary heat exchanger for heat exchange to the dehydrogenation reactor and the tail gas treatment device in real time.

[0007] Optionally, a reaction zone, a mixing zone, an air layer, a waste gas layer and a rear-end conveying zone are provided in the dehydrogenation reactor. The reaction zone is connected to the hydrogen-rich hydrogen oil storage tank pipeline, the mixing zone is located between the reaction zone and the rear-end conveying zone, the rear-end conveying zone is respectively connected to the thermostat and the hydrogen-depleted hydrogen oil storage tank, the air layer is located outside the reaction zone, the air layer is respectively connected to the third air distribution valve and the first air distribution valve, the waste gas layer is located outside the air layer, and the waste gas layer is connected to the secondary heat exchanger.

[0008] This application also proposes a thermal self-balancing fuel cell power generation method, which is implemented based on the aforementioned thermal self-balancing fuel cell power generation system. The method includes the following steps:

[0009] Pumping the hydrogen-rich oil into the dehydrogenation reactor for dehydrogenation reaction to obtain hydrogen-poor oil, hot hydrogen and hot air;

[0010] Mixing a first preset amount of the hot air with external cold air to form mixed air, and then passing a second preset amount of the mixed air through the primary heat exchanger for heat exchange, and then passing the mixed air together with the hot hydrogen into the thermostat for temperature balancing to obtain a gas mixture;

[0011] Passing the gas mixture into the SOFC stack to generate electricity;

[0012] Passing the unused gas mixture after power generation by the SOFC stack and the third preset amount of hot air into the tail gas treatment device, and burning them to obtain high-temperature exhaust gas;

[0013] The high-temperature exhaust gas passes through the primary heat exchanger and the secondary heat exchanger in sequence for heat exchange, and then is introduced into the dehydrogenation reactor to provide heat for the dehydrogenation reaction.

[0014] Optionally, after the step of subjecting the second preset amount of mixed air to heat exchange in the primary heat exchanger, the method further comprises:

[0015] After the fourth preset amount of mixed air passes through the secondary heat exchanger for heat exchange, a portion thereof is introduced into the dehydrogenation reactor to provide heat for the dehydrogenation reaction, and the other portion is mixed with the hot air.

[0016] Optionally, the step of passing the high-temperature exhaust gas through the primary heat exchanger and the secondary heat exchanger in sequence for heat exchange and then passing the high-temperature exhaust gas into the dehydrogenation reactor to provide heat for the dehydrogenation reaction includes:

[0017] Passing the high-temperature exhaust gas into the primary heat exchanger and exchanging heat with the mixed gas in the primary heat exchanger to obtain medium-temperature exhaust gas;

[0018] Passing the medium-temperature exhaust gas into the secondary heat exchanger and performing heat exchange with the mixed gas in the secondary heat exchanger to obtain exhaust gas;

[0019] Passing the exhaust gas into the dehydrogenation reactor to provide heat for the dehydrogenation reaction;

[0020] The waste gas after passing through the dehydrogenation reactor is used in the back-end thermal energy supply system.

[0021] Optionally, the inlet temperature of the SOFC stack is 580°C-620°C, and the outlet temperature of the SOFC stack is ≤700°C.

[0022] Optionally, the outlet temperature of the tail gas treatment device is ≤900°C.

[0023] Optionally, the reaction temperature in the dehydrogenation reactor is 180°C-220°C.

[0024] The beneficial effects of this application include:

[0025] The power generation system of the present application includes a hydrogen-rich hydrogen-oil storage tank, a dehydrogenation reactor and a hydrogen-poor hydrogen-oil storage tank connected in sequence, and also includes a thermostat, an SOFC stack and an exhaust gas treatment device. The hydrogen end of the dehydrogenation reactor is connected to the thermostat, the thermostat is connected to the SOFC stack, the SOFC stack is connected to the exhaust gas treatment device, the air end of the dehydrogenation reactor is connected to the exhaust gas treatment device, and the exhaust gas end of the exhaust gas treatment device 7 is respectively connected to the thermostat and the dehydrogenation reactor. The hydrogen-rich oil storage tank 1 is used to store the hydrogen-rich oil transported from a place far away from the hydrogen usage scene. The dehydrogenation reactor transfers the heat of the high-temperature gas entering from the outside to the dehydrogenation reaction zone, so that the hydrogen-rich oil is efficiently dehydrogenated under the action of the dehydrogenation catalyst within a stable temperature range, and then the hydrogen-poor oil is stored in the hydrogen-poor oil storage tank after dehydrogenation in the dehydrogenation reactor. The thermostat balances the temperature of the hot hydrogen after dehydrogenation and the air after heat exchange, so that the anode and cathode gases entering the SOFC stack are at a suitable temperature, and the battery cells will not fail due to damage, degumming, etc. due to excessive temperature difference between the anode and cathode gases. The SOFC stack then generates electricity through electrochemical reaction of hydrogen and oxygen within a suitable reaction temperature range. Finally, the exhaust gas treatment device completely burns the unreacted gas of the SOFC stack to release more heat energy. The exhaust gas treated by the exhaust gas treatment device is heat exchanged with the air before entering the dehydrogenation reactor 3 to provide a dehydrogenation reaction temperature environment. Based on the current SOFC-based multi-level energy utilization framework, this application organically couples LOHC technology to further improve the comprehensive utilization rate of energy; and in view of the large demand for thermal energy at the LOHC dehydrogenation end, the high-grade thermal energy at the SOFC back end is utilized, so that the LOHC dehydrogenation equipment can be directly connected to the power generation scenario of the SOFC equipment, simplifying the process from hydrogen-rich hydrogen oil to hydrogen-using equipment, and solving the problem of thermal energy demand for the application of LOHC at the dehydrogenation end; and this application reasonably controls the heat self-balancing power generation system, so that the dehydrogenation reactor and SOFC stack are always in a better operating temperature range, increasing the system efficiency while extending the system life. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0027] Figure 1 This is a schematic structural diagram of the heat self-balancing fuel cell power generation system described in an embodiment of the present application;

[0028] Figure 2Schematic diagram of the internal structure of the dehydrogenation reactor described in the embodiment of the present application.

[0029] Reference numerals:

[0030] 1-Hydrogen-rich hydrogen oil storage tank; 2-Transfer pump; 3-Dehydrogenation reactor; 31-Reaction zone; 32-Mixing zone; 33-Air layer; 34-Waste gas layer; 35-Back-end delivery zone; 4-Hydrogen-poor hydrogen oil storage tank; 5-Thermostats; 6-SOFC stack; 7-Tail gas treatment device; 8-First stage heat exchanger; 9-Second stage heat exchanger; 10-First gas distribution valve; 11-Second gas distribution valve; 12-Third gas distribution valve.

[0031] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0033] An embodiment of the present application provides a heat self-balancing fuel cell power generation system, comprising a hydrogen-rich hydrogen oil storage tank 1, a dehydrogenation reactor 3 and a hydrogen-poor hydrogen oil storage tank 4 connected in sequence, and also comprising a thermostat 5, an SOFC stack 6 and an exhaust gas treatment device 7, wherein the hydrogen end of the dehydrogenation reactor 3 is connected to the thermostat 5, the thermostat 5 is connected to the SOFC stack 6, the SOFC stack 6 is connected to the exhaust gas treatment device 7, the air end of the dehydrogenation reactor 3 is connected to the exhaust gas treatment device 7, and the exhaust gas end of the exhaust gas treatment device 7 is respectively connected to the thermostat 5 and the dehydrogenation reactor 3.

[0034] In the present application, the hydrogen-rich oil storage tank 1 is used to store hydrogen-rich oil (i.e., hydrogen-rich oil after hydrogen addition) transported from a place far away from the hydrogen usage scene; the dehydrogenation reactor 3 is used to transfer the heat of the high-temperature gas entering from the outside to the dehydrogenation reaction zone, so that the hydrogen-rich oil is efficiently dehydrogenated under the action of the dehydrogenation catalyst within a stable temperature range; the hydrogen-poor oil storage tank 4 is used to store the hydrogen-poor oil after dehydrogenation in the dehydrogenation reactor (i.e., hydrogen-free oil that contains almost no hydrogen after dehydrogenation); the thermostat 5 is used to balance the temperature of the hot hydrogen after dehydrogenation and the air after heat exchange, so that the anode and cathode gases entering the SOFC stack 6 are both at 600°C, and the battery cells will not fail due to damage, debonding, etc. due to excessive temperature difference between the anode and cathode gases; the SOFC stack 6 is used to generate electricity through electrochemical reaction of hydrogen and oxygen within a suitable reaction temperature range; the exhaust gas treatment device 7 is used to completely burn the unreacted gas of the SOFC stack 6 to release more heat energy.

[0035] like Figure 1 and Figure 2 As shown, for ease of understanding, this application marks the main paths in the system, among which path A is the air after heat exchange through the first-stage heat exchanger 8; path B is the air after temperature equalization through the thermostat 5; path C is the hot hydrogen after dehydrogenation through the dehydrogenation reactor 3; path D is the hydrogen after temperature equalization through the thermostat 5; path E is the high-temperature exhaust gas generated after combustion through the exhaust treatment device 7; path F is the medium-temperature exhaust gas after heat exchange of the high-temperature exhaust gas through the first-stage heat exchanger 8; path G is the exhaust gas after two-stage heat exchange, which is passed into the dehydrogenation reactor 3 and the air with a temperature close to that of path N provides the dehydrogenation reaction temperature environment to the dehydrogenation reactor 3; path H is Air that has undergone heat exchange in the secondary heat exchanger 9; Path I is the air leaving the dehydrogenation reactor 3; Path J is used to control the temperature of the tail gas treatment device 7; Path K is the exhaust gas after passing through the dehydrogenation reactor 3. Path K is used to return the remaining air in Path J to the front end of the cold air inlet outside the system to increase the intake temperature, thereby more efficiently utilizing the heat in the air; Path L is the path for the hydrogen-depleted hydrogen oil to flow into the hydrogen-depleted hydrogen oil storage tank 4 after condensation after dehydrogenation; Path M is the air distributed by the third air distribution valve 12 and merged into Path I; Path N is the air distributed by the third air distribution valve 12 and entering the dehydrogenation reactor 3 to provide a thermal environment for the reaction; Path O is the path for the hydrogen-rich hydrogen oil to enter the dehydrogenation reactor 3. The above notation will continue to be used for subsequent descriptions.

[0036] The overall operation process of the system of the present application is as follows: the hydrogen-rich oil stored in the hydrogen-rich oil storage tank 1 is sent to the dehydrogenation reactor 3 for dehydrogenation reaction to obtain hydrogen-poor oil, hot hydrogen and hot air; the hydrogen-poor oil is stored in the hydrogen-poor oil storage tank 4; the hot air is distributed in real time to the J route to enter the exhaust gas treatment device 7, and to the K route to mix with the external cold air to form mixed air, thereby increasing the intake temperature; part of the mixed air is passed through the thermostat 5 together with the hot hydrogen after heat exchange for temperature balance to obtain a gas mixture; and the remaining part of the mixed air is distributed in real time to the N The gas mixture in the thermostat 5 is passed into the SOFC stack 6 to generate electricity; the gas mixture not fully utilized after the SOFC stack 6 generates electricity is passed into the exhaust gas treatment device 7 for complete combustion to release more heat energy, thereby obtaining high-temperature exhaust gas; the mixed gas is heat-displaced by the high-temperature exhaust gas, and the obtained exhaust gas is passed into the dehydrogenation reactor 3, and together with the mixed air with a temperature close to that of the N path, provides the dehydrogenation reaction temperature to the dehydrogenation reactor 3.

[0037] As an implementable embodiment of the present application, the system also includes a primary heat exchanger 8 and a secondary heat exchanger 9, the air inlet end of the primary heat exchanger 8 is respectively connected to the exhaust gas end of the exhaust gas treatment device 7 and the external cold air pipeline, the exhaust gas end of the primary heat exchanger 8 is connected to the air inlet end of the secondary heat exchanger 9, the air outlet end of the primary heat exchanger 8 is connected to the thermostat 5, the air inlet end of the secondary heat exchanger 9 is also connected to the external cold air pipeline, the exhaust gas end of the secondary heat exchanger 9 is connected to the dehydrogenation reactor 3, and the air outlet end of the secondary heat exchanger 9 is respectively connected to the dehydrogenation reactor 3 and the exhaust gas treatment device 7.

[0038] In the present application, the primary heat exchanger 8 is used to replace the heat of the high-temperature exhaust gas (mainly water vapor, nitrogen, and oxygen) after combustion in the exhaust treatment device 7 with the external cold air with a lower temperature from the front end. This air is used to enter the SOFC stack as cathode gas; the secondary heat exchanger 9 is used to replace the heat of the medium-temperature exhaust gas passing through the primary heat exchanger 8 with the air with a lower temperature from the front end. This air is used to provide a suitable dehydrogenation temperature environment for the dehydrogenation reactor 3.

[0039] As an embodiment of the present application, the system further includes a first air distribution valve 10, a second air distribution valve 11 and a third air distribution valve 12, wherein the first air distribution valve 10 is located on the pipeline between the dehydrogenation reactor 3 and the tail gas treatment device 7; the second air distribution valve 11 is located on the pipeline through which external cold air enters the primary heat exchanger 8 and the secondary heat exchanger 9; and the third air distribution valve 12 is connected to the air outlet end of the secondary heat exchanger 9.

[0040] In the present application, the first air distribution valve 10 is used to distribute the air leaving the dehydrogenation reactor 3 to the exhaust gas treatment device 7 and the air intake end of the external cold air in real time, so as to more efficiently utilize the heat in the air; the second air distribution valve 11 is used to distribute the mixed gas of the external cold air and the air distributed by the first air distribution valve 10 to the primary heat exchanger 8 and the secondary heat exchanger 9 in real time; the third air distribution valve 12 is used to distribute the air that has passed through the secondary heat exchanger 9 to the dehydrogenation reactor 3 and the exhaust gas treatment device 7 in real time.

[0041] As an embodiment of the present application, the dehydrogenation reactor 3 is provided with a reaction zone 31, a mixing zone 32, an air layer 33, a waste gas layer 34 and a rear-end conveying zone 35. The reaction zone 31 is connected to the hydrogen-rich hydrogen oil storage tank 1 by a pipeline, and the mixing zone 32 is located between the reaction zone 31 and the rear-end conveying zone 35. The rear-end conveying zone 35 is respectively connected to the thermostat 5 and the hydrogen-poor hydrogen oil storage tank 4. The air layer 33 is located outside the reaction zone 31. The air layer 33 is respectively connected to the third gas distribution valve 12 and the first gas distribution valve 10. The waste gas layer 34 is located outside the air layer 33. The waste gas layer 34 is connected to the secondary heat exchanger 9.

[0042] like Figure 2 As shown, the reaction zone 31 is the dehydrogenation catalyst attachment layer, and the hydrogen-rich oil enters the reaction zone 31 for reaction; the mixing zone 32 is the mixing zone of the hydrogen and the hydrogen-poor oil after dehydrogenation, to be separated at the rear end; the air layer 33 is the area where the rear end of the pipeline N enters; the exhaust gas layer 34 is the area where the rear end of the gas path G enters; the rear end delivery zone 35 is the hydrogen delivery and hydrogen-poor oil condensation area.

[0043] The reaction zone 31 in this application has a conical structure, and its cross-sectional area gradually increases along the direction of the hydrogen-rich oil. At the same time, the cross-sectional area of the air layer 33 gradually decreases along the direction of the air. The direction of the exhaust gas in the exhaust gas layer 34 is opposite to the direction of the air in the air layer 33. This is to meet the surge in volume after the dehydrogenation of the hydrogen-rich oil, balance the heat transfer between the reaction zone 31 and the air layer 33, and compensate for the cooling of the air in the air layer 33 along the way by the heat of the exhaust gas. Through the design of the dehydrogenation reactor 3 structure, the dehydrogenation reaction temperature can be always controlled within the appropriate temperature range through the reasonable layout of the external gas path and the control of the gas flow.

[0044] Specifically, the dehydrogenation catalyst can be an Ag-based catalyst, a Pt-based catalyst, a Pd-based catalyst, an Au-based catalyst, a Ru-based catalyst, a Ni-based catalyst, or a supported (support includes porous materials such as Al2O3, SiO2, molecular sieves, activated carbon, etc.) or unsupported catalyst formed by the above metals and transition metals (Cu, Mg, Ti, Fe, etc.) or transition metal oxides (CuO, MgO, TiO2, Fe2O3, etc.).

[0045] As an implementation method of the present application, a delivery pump 2 is provided between the hydrogen-rich hydrogen oil storage tank 1 and the dehydrogenation reactor 3 .

[0046] The embodiments of the present application further provide a thermal self-balancing fuel cell power generation method, which is implemented based on the aforementioned thermal self-balancing fuel cell power generation system and includes the following steps:

[0047] S10, pumping the hydrogen-rich oil into the dehydrogenation reactor 3 for dehydrogenation reaction to obtain hydrogen-poor oil, hot hydrogen and hot air.

[0048] Specifically, the temperature of the reaction zone 31 in the dehydrogenation reactor 3 is 180°C-220°C. Since the reaction temperature of the dehydrogenation catalyst in the reaction zone 31 is 180°C-220°C, it is necessary to control the temperature in the reaction zone 31 to be 180°C-220°C. On the one hand, the present application uses the waste gas in the waste gas layer 34 to exchange heat with the wall of the air in the air layer 33. At the same time, in order to avoid the uneven temperature in the reaction zone 31 caused by the temperature drop during the flow of air in the air layer 33, the present application sets the flow direction of the high-temperature waste gas in the waste gas layer 34 to be opposite to the flow direction of the air in the air layer 33, so as to compensate for the cooling of the air in the air layer 33 along the way. This achieves the effect of compensating for the temperature drop gradient in the air layer 33 and compensating for the insufficient heating capacity in the air layer 33; on the other hand, in order to maintain a relatively constant temperature range in the reaction zone 31, the present application controls the flow rate of air in path N by controlling the opening of the third air distribution valve 12 flowing to path N. If the flow rate in N increases or decreases, the flow rate in the air layer 33 will increase or decrease accordingly, and accordingly more or less heat will be transferred to the reaction zone 31, so that the reaction temperature in the reaction zone 31 can be adaptively controlled by controlling the opening of the third air distribution valve 12.

[0049] In addition, the reaction zone 31 in the present application is set to a conical structure, and its cross-sectional area gradually increases along the direction of the hydrogen-rich oil, which can not only meet the surge in volume from hydrogen-rich oil to hydrogen removal, but also the change in the shape of the reaction zone 31 also causes the cross-sectional area of the air layer 33 to decrease along the way. As the air flow rate along the air layer 33 increases, the heat transfer between the reaction zone 31 and the air layer 33 can be better balanced.

[0050] S20, mixing a first preset amount of hot air with external cold air to form mixed air, and then passing a second preset amount of mixed air through the primary heat exchanger 8 for heat exchange, and then passing the mixed air together with the hot hydrogen into the thermostat 5 for temperature balance to obtain a gas mixture.

[0051] Specifically, the first preset amount of hot air is the part of hot air that is distributed to the air intake end of the external cold air in real time through the first air distribution valve 10; the second preset amount of mixed air is the part of mixed air that is distributed to the first-stage heat exchanger 8 in real time through the second air distribution valve 11.

[0052] S30. After the fourth preset amount of mixed air passes through the secondary heat exchanger 9 for heat exchange, a portion of the mixed air is introduced into the dehydrogenation reactor 3 to provide heat for the dehydrogenation reaction, and the other portion is mixed with the hot air.

[0053] Specifically, the fourth preset amount of mixed air is the portion of mixed air distributed to the secondary heat exchanger 9 in real time via the second air distribution valve 11 .

[0054] S40, introducing the gas mixture into the SOFC stack 6 to generate electricity.

[0055] Specifically, the inlet temperature of the SOFC stack 6 is 580°C-620°C, and the outlet temperature of the SOFC stack 6 is ≤700°C. The temperature within the SOFC stack 6 is controlled to reduce the temperature gradient across the cell and increase reliability and durability. The inlet temperature is determined by the front-end air supply temperature, while the outlet temperature is controlled by the air flow through the primary heat exchanger 8. Increasing this air flow reduces the cathode temperature of the SOFC stack 6 and also reduces the anode temperature. Reducing this air flow increases both the cathode temperature and the anode temperature of the SOFC stack 6.

[0056] S50 , introducing the unused gas mixture after power generation by the SOFC stack 6 and the third preset amount of hot air into the tail gas treatment device 7 , and obtaining high-temperature exhaust gas after combustion.

[0057] During specific implementation, the outlet temperature of the exhaust gas treatment device 7 is ≤ 900°C. Controlling the outlet temperature of the exhaust gas treatment device 7 below 900°C is to prevent material failures such as high-temperature creep. This temperature is primarily controlled by the air flow rate from the first air distribution valve 10 to the J circuit. A larger opening of the J circuit lowers the E circuit temperature; a smaller opening of the J circuit raises the E circuit temperature.

[0058] Specifically, the third preset amount of hot air is the portion of hot air distributed to the exhaust gas treatment device 7 in real time via the first air distribution valve 10 .

[0059] S60, passing the high-temperature exhaust gas into the primary heat exchanger 8 and performing heat exchange with the mixed gas in the primary heat exchanger 8 to obtain medium-temperature exhaust gas;

[0060] The medium-temperature exhaust gas is passed into the secondary heat exchanger 9 and heat exchanged with the mixed gas in the secondary heat exchanger 9 to obtain exhaust gas;

[0061] Passing the exhaust gas into the dehydrogenation reactor 3 to provide heat for the dehydrogenation reaction;

[0062] The waste gas after passing through the dehydrogenation reactor 3 is used in the back-end thermal energy supply system.

[0063] During the specific implementation process, the exhaust gas after passing through the dehydrogenation reactor 3 can be used to provide hot air for heating in a closed environment after passing through an air-to-air heat exchanger again; it can also be used to provide hot water to related scenes through a water-to-air heat exchanger again; or a temperature difference power generation device can be used to continuously utilize the heat of the exhaust gas. This part of the power generation power can partially or even completely meet the power consumption of the compressor pumping external cold air and the pump pumping hydrogen-rich oil.

[0064] Example 1

[0065] A thermal self-balancing fuel cell power generation method is implemented based on the aforementioned thermal self-balancing fuel cell power generation system, comprising the following steps:

[0066] The hydrogen-rich oil stored in the hydrogen-rich oil storage tank 1 is pumped into the dehydrogenation reactor 3 via the delivery pump 2, and dehydrogenation reaction is carried out at 200°C to obtain hydrogen-poor oil, hot hydrogen at 200°C and hot air at 250°C;

[0067] Storing the hydrogen-poor hydrogen oil in the hydrogen-poor hydrogen oil storage tank 4;

[0068] The first air distribution valve 10 distributes 250°C hot air to lines J and K in real time. The air temperature in line J is 220°C. The temperature of the exhaust gas treatment device 7 is controlled by controlling the flow rate in line J, so that the outlet temperature of the exhaust gas treatment device 7 is ≤ 900°C. Line K is used to return the remaining air in line J to the front end of the system's external cold air inlet, where it is mixed with the external cold air at 20°C to form mixed air, thereby raising the intake air temperature. At the same time, the intake volume of the external cold air is also controlled by an unlabeled air flow meter at the front end according to system requirements.

[0069] The second air distribution valve 11 distributes the mixed air to the primary heat exchanger 8 and the secondary heat exchanger 9 in real time. The mixed air, which reaches 650°C after heat exchange in the primary heat exchanger 8, is introduced into the thermostat 5 together with the hot hydrogen at 200°C for temperature balance, thereby obtaining a gas mixture at 600°C.

[0070] After the mixed air has been heat exchanged in the secondary heat exchanger 9, it is distributed in real time by the third air distribution valve 12 to the N route (entering the dehydrogenation reactor 3 to provide a thermal environment) and the M route (skipping the dehydrogenation reactor 3 and merging into the I route).

[0071] Passing the gas mixture into the SOFC stack 6 to generate electricity;

[0072] The unused gas mixture after power generation by the SOFC stack 6 is passed into the tail gas treatment device 7 for complete combustion to release more heat energy, thereby obtaining a high-temperature exhaust gas of 900°C.

[0073] The high-temperature exhaust gas is passed into the primary heat exchanger 8 and heat exchanged with the mixed gas in the primary heat exchanger 8 to obtain a medium-temperature exhaust gas of 600°C;

[0074] The medium-temperature exhaust gas is passed into the secondary heat exchanger 9 and heat exchanged with the mixed gas in the secondary heat exchanger 9 to obtain exhaust gas at 350°C;

[0075] The exhaust gas is introduced into the dehydrogenation reactor 3, and together with the mixed air of the N-way with the same temperature of 350°C, provides the dehydrogenation reaction temperature for the dehydrogenation reactor 3;

[0076] The waste gas after passing through the dehydrogenation reactor 3 is used in other back-end thermal energy supply systems.

[0077] The theoretical basis for calculating the fluid temperature in this embodiment is:

[0078] The SOFC stack 6 typically has a power generation efficiency of 55%, a fuel utilization rate within the SOFC stack 6 of 75%, an external cold air temperature of 20°C, a heat requirement of 53.5 kJ / mol H2 for the dehydrogenation reaction, and an air excess coefficient within the SOFC stack 6 maintained between 2.5 and 3.5. Assuming a 5% heat loss along each path within the system, the temperature of the fluid in each path within the system is derived.

[0079] The above description is merely an optional embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made using the contents of the present application specification and drawings under the inventive concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A thermal self-balancing fuel cell power generation system, characterized in that: The invention comprises a hydrogen-rich hydrogen oil storage tank, a dehydrogenation reactor and a hydrogen-poor hydrogen oil storage tank connected in sequence, and also comprises a thermostat, an SOFC stack and an exhaust gas treatment device, wherein the hydrogen end of the dehydrogenation reactor is connected to the thermostat, the thermostat is connected to the SOFC stack, the SOFC stack is connected to the exhaust gas treatment device, the air end of the dehydrogenation reactor is connected to the exhaust gas treatment device, and the exhaust gas end of the exhaust gas treatment device is connected to the thermostat and the dehydrogenation reactor respectively; Among them, the dehydrogenation reactor is provided with a reaction zone, a mixing zone, an air layer, a waste gas layer and a rear-end conveying zone. The reaction zone is connected to the hydrogen-rich hydrogen oil storage tank pipeline, the mixing zone is located between the reaction zone and the rear-end conveying zone, the rear-end conveying zone is respectively connected to the thermostat and the hydrogen-poor hydrogen oil storage tank, the air layer is located outside the reaction zone, and the waste gas layer is located outside the air layer.

2. The thermal self-balancing fuel cell power generation system according to claim 1, characterized in that: The system also includes a primary heat exchanger and a secondary heat exchanger. The air inlet end of the primary heat exchanger is respectively connected to the exhaust gas end of the exhaust gas treatment device and the external cold air pipeline, the exhaust gas end of the primary heat exchanger is connected to the air inlet end of the secondary heat exchanger, the air outlet end of the primary heat exchanger is connected to the thermostat, the air inlet end of the secondary heat exchanger is also connected to the external cold air pipeline, the exhaust gas end of the secondary heat exchanger is connected to the dehydrogenation reactor, and the air outlet end of the secondary heat exchanger is respectively connected to the dehydrogenation reactor and the exhaust gas treatment device.

3. The thermal self-balancing fuel cell power generation system according to claim 2, characterized in that: The system also includes a first air distribution valve, a second air distribution valve and a third air distribution valve. The first air distribution valve is located on the pipeline between the dehydrogenation reactor and the tail gas treatment device, and the first air distribution valve is used to distribute the air leaving the dehydrogenation reactor to the air inlet end of the tail gas treatment device and the external cold air in real time; the second air distribution valve is located on the pipeline where the external cold air enters the first heat exchanger and the second heat exchanger, and the second air distribution valve is used to distribute the mixed gas of the external cold air and the air distributed by the first air distribution valve to the first heat exchanger and the second heat exchanger in real time; the third air distribution valve is connected to the air outlet end of the second heat exchanger, and the third air distribution valve is used to distribute the air that has passed through the second heat exchanger for heat exchange to the dehydrogenation reactor and the tail gas treatment device in real time.

4. The thermal self-balancing fuel cell power generation system according to claim 3, characterized in that: The air layer is connected to the third air distribution valve and the first air distribution valve respectively, and the exhaust gas layer is connected to the secondary heat exchanger.

5. A fuel cell power generation method with thermal self-balancing, characterized in that: Based on the thermal self-balancing fuel cell power generation system according to any one of claims 2 to 4, the method comprises the following steps: Pumping the hydrogen-rich oil into the dehydrogenation reactor for dehydrogenation reaction to obtain hydrogen-poor oil, hot hydrogen and hot air; Mixing a first preset amount of the hot air with external cold air to form mixed air, and then passing a second preset amount of the mixed air through the primary heat exchanger for heat exchange, and then passing the mixed air together with the hot hydrogen into the thermostat for temperature balancing to obtain a gas mixture; Passing the gas mixture into the SOFC stack to generate electricity; Passing the unused gas mixture after power generation by the SOFC stack and the third preset amount of hot air into the tail gas treatment device, and burning them to obtain high-temperature exhaust gas; The high-temperature exhaust gas passes through the primary heat exchanger and the secondary heat exchanger in sequence for heat exchange, and then is introduced into the dehydrogenation reactor to provide heat for the dehydrogenation reaction.

6. The thermal self-balancing fuel cell power generation method according to claim 5, characterized in that: After the step of subjecting the second preset amount of mixed air to heat exchange in the primary heat exchanger, the method further comprises: After the fourth preset amount of mixed air passes through the secondary heat exchanger for heat exchange, a portion thereof is introduced into the dehydrogenation reactor to provide heat for the dehydrogenation reaction, and the other portion is mixed with the hot air.

7. The thermal self-balancing fuel cell power generation method according to claim 6, characterized in that: The step of passing the high-temperature exhaust gas through the primary heat exchanger and the secondary heat exchanger in sequence for heat exchange and then passing the high-temperature exhaust gas into the dehydrogenation reactor to provide heat for the dehydrogenation reaction comprises: Passing the high-temperature exhaust gas into the primary heat exchanger and exchanging heat with the mixed gas in the primary heat exchanger to obtain medium-temperature exhaust gas; Passing the medium-temperature exhaust gas into the secondary heat exchanger and performing heat exchange with the mixed gas in the secondary heat exchanger to obtain exhaust gas; Passing the exhaust gas into the dehydrogenation reactor to provide heat for the dehydrogenation reaction; The waste gas after passing through the dehydrogenation reactor is used in the back-end thermal energy supply system.

8. The thermal self-balancing fuel cell power generation method according to claim 5, characterized in that: The inlet temperature of the SOFC stack is 580°C-620°C, and the outlet temperature of the SOFC stack is ≤700°C.

9. The thermal self-balancing fuel cell power generation method according to claim 5, characterized in that: The outlet temperature of the tail gas treatment device is ≤900°C.

10. The thermal self-balancing fuel cell power generation method according to claim 5, characterized in that: The reaction temperature in the dehydrogenation reactor is 180°C-220°C.

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