Solid oxide fuel cell power supply system coupled with organic Rankine cycle

Abstract

The invention belongs to the technical field of ship power systems, and relates to an organic Rankine cycle coupled solid oxide fuel cell power supply system and method, and the system comprises a solid oxide fuel cell, a power supply unit, and a waste heat recycling unit. And the organic Rankine cycle unit is used for recycling waste heat in the tail gas. Catalytic reforming and catalytic combustion are integrated on the two sides of the compact reformer, direct conduction of heat is achieved, the occupied volume on a ship is reduced, the heat integration efficiency is improved, meanwhile, tail gas of the solid oxide fuel cell is used for carrying out a catalytic combustion reaction on the combustion side of the compact reformer to supply heat to the catalytic reforming reaction, and the energy consumption is reduced. Dependence of an external heat source is avoided, the energy self-sufficiency rate of the system is increased, air and natural gas are preheated through multi-stage heat exchange, part of waste heat of the system is recycled, energy consumption is reduced, in addition, low-temperature waste heat is recycled through organic Rankine cycle for power generation, and the overall energy utilization rate is greatly increased by utilizing the efficient heat-work conversion characteristic of an organic working medium in a medium-low temperature interval.

Description

Technical Field

[0001] This invention belongs to the field of marine propulsion system technology and relates to a solid oxide fuel cell power supply system coupled with an organic Rankine cycle. Background Technology

[0002] As a pillar of global trade, the shipping industry supports the development of the world economy but also brings serious pollution. With the increasing severity of the global energy crisis, many scholars have conducted extensive research on the application of renewable energy sources such as solar, wind, and ocean energy in ships. However, these energy sources inherently suffer from volatility, intermittency, and randomness, limiting their large-scale application to a practical stage. Solid oxide fuel cells, on the other hand, possess high power density, high overall thermal efficiency, and can directly utilize hydrocarbons such as onboard natural gas as fuel, making them a promising option for future ship propulsion.

[0003] Currently, the core components of existing shipborne oxide fuel cell systems include a pre-reformer, a fuel cell stack, an afterburner, and supply and exhaust pipelines. Shipborne hydrocarbon fuels such as natural gas are first converted into hydrogen-rich gas by the pre-reformer, which is then introduced into the fuel cell stack anode and cathode to undergo an electrochemical reaction with the air input, realizing the conversion of chemical energy into electrical energy. The exhaust gas generated during the reaction is discharged into the afterburner for treatment. This exhaust gas is either directly discharged or its residual heat is used to heat the pre-reformer.

[0004] However, in existing systems, the pre-reformer and afterburner are designed with a separate layout. They are connected by independent pipelines and occupy separate installation space on the ship. This not only significantly increases the overall size of the system, but also creates a significant contradiction with the compact installation requirements of the ship's power compartment. At the same time, the separate structure causes some heat loss during the transmission of exhaust gas combustion waste heat, which cannot be fully transferred to the pre-reformer to meet the high-temperature requirements of hydrocarbon fuel conversion. This results in insufficient energy utilization and low overall energy conversion efficiency of the system, making it difficult to meet the core requirements of ship power systems for compactness and high operational efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a solid oxide fuel cell power supply system coupled with an organic Rankine cycle, which can reduce the overall system volume while recovering and utilizing the system's waste heat, thereby improving the overall energy conversion efficiency of the system.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows: A solid oxide fuel cell power supply system coupled with an organic Rankine cycle, comprising a solid oxide fuel cell with a cathode inlet for introducing air, characterized in that it further comprises: The power supply unit includes a steam generator, a first mixer, and a compact reformer connected in sequence. The compact reformer has a cold channel and a hot channel inside. The cold channel is connected to the first mixer and the anode inlet of the solid oxide fuel cell, respectively. The hot channel is connected to the anode outlet and the cathode outlet of the solid oxide fuel cell. The steam generator is used to generate steam. Natural gas enters the first mixer and mixes with the steam from the steam generator before entering the cold channel of the compact reformer for catalytic reforming. Subsequently, it reacts with air in the solid oxide fuel cell to convert chemical energy into electrical energy. The waste heat recovery and utilization unit includes a second mixer connected to a solid oxide fuel cell and a hot channel, and a first heat exchanger and a second heat exchanger connected in sequence. The first heat exchanger is connected to the solid oxide fuel cell, and the second heat exchanger is connected to the first mixer. The anode exhaust gas and cathode exhaust gas of the solid oxide fuel cell are mixed in the second mixer and then enter the hot channel for catalytic combustion reaction to provide heat for catalytic reforming reaction and generate combustion-side exhaust gas. Then, the combustion-side exhaust gas is divided into two paths by a one-to-two multi-way valve. One path enters the steam generator to heat water to generate steam, and the other path enters the second heat exchanger and the first heat exchanger in sequence after passing through the waste heat boiler. Natural gas enters from the second heat exchanger for preheating, and air enters from the first heat exchanger for preheating. The organic Rankine cycle unit, connected to the thermal passage of the compact reformer, is used to reuse the residual heat in the exhaust gas.

[0007] The invention is further characterized by: The organic Rankine cycle unit includes a waste heat boiler, an expander, a condenser, and a booster pump connected in sequence. The waste heat boiler is connected to the second heat exchanger, and the output shaft of the expander is connected to a generator.

[0008] The compact reformer is a plate-type microreactor with a coated wall. One side of the substrate of the compact reformer is coated with a reforming catalyst to form a cold channel, and the other side of the substrate is coated with a combustion catalyst to form a hot channel.

[0009] A method for powering a solid oxide fuel cell coupled with an organic Rankine cycle includes the following steps: Steam generated by the steam generator enters the first mixer. Natural gas is preheated in the second heat exchanger and then enters the first mixer. The steam and natural gas are mixed in the first mixer and then enter the compact reformer for catalytic reforming. Subsequently, it enters the solid oxide fuel cell and reacts with the air preheated in the first heat exchanger to convert chemical energy into electrical energy. After the anode and cathode exhaust gases of the solid oxide fuel cell are mixed in the second mixer, they enter the compact reformer for catalytic combustion reaction to provide heat for the catalytic reforming reaction and generate combustion-side exhaust gas. Then, the combustion-side exhaust gas is divided into two paths by a one-to-two multi-way valve. One path enters the steam generator to heat water and generate steam, and the other path passes through the waste heat boiler and enters the second heat exchanger and the first heat exchanger in sequence to preheat natural gas and air. The exhaust gas from the combustion side enters the waste heat boiler and exchanges heat with the pressurized liquid organic working fluid from the booster pump before being discharged. The liquid organic working fluid becomes superheated organic working fluid steam, which enters the expander to expand and do work, outputting mechanical energy to drive the generator to generate electricity. After expanding and doing work, the low-pressure organic working fluid steam enters the condenser to condense and becomes liquid organic working fluid, continuing the cycle.

[0010] When steam and natural gas are mixed in the first mixer, the molar ratio of steam to natural gas is (2.5~3.5):1.

[0011] The steam and natural gas are mixed in the first mixer and then enter the cold channel of the compact reformer for catalytic reforming.

[0012] In the solid oxide fuel cell, the anode exhaust gas and cathode exhaust gas are mixed in the second mixer and then enter the hot channel of the compact reformer for catalytic combustion reaction.

[0013] The organic Rankine cycle unit uses an organic working fluid, which is saturated or superheated at the outlet of the waste heat boiler.

[0014] The organic working fluid is a non-azeotropic mixture of R245fa or R245fa and R1234yf in a certain proportion.

[0015] The solid oxide fuel cell power supply system and method coupled with an organic Rankine cycle of the present invention have the following advantages: This invention integrates catalytic reforming and catalytic combustion on both sides of a compact reformer, enabling direct heat transfer. This avoids the integration of pre-reformers and afterburners in traditional systems, reducing the volume occupied on board and improving thermal integration efficiency. Simultaneously, the solid oxide fuel cell exhaust gas undergoes catalytic combustion on the combustion side of the compact reformer to heat the catalytic reforming reaction, avoiding dependence on external heat sources and improving the system's energy self-sufficiency. Multi-stage heat exchange preheats air and natural gas, recovering and utilizing some of the system's waste heat, reducing energy consumption. Furthermore, by combining an organic Rankine cycle, the waste heat of the exhaust gas, which still has usable value after multiple heat exchange sessions, is deeply recovered and converted into additional electrical energy. This achieves multi-stage efficient conversion of fuel chemical energy → electrical energy → waste heat → mechanical energy → electrical energy, significantly improving overall energy utilization. It is suitable for space-constrained scenarios such as ships and islands with diverse energy needs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the compact reformer in this invention.

[0018] Figure 3 This is a schematic diagram of the overall process of the present invention.

[0019] Figure label: 1. Steam generator; 2. First mixer; 3. Compact reformer; 4. Second mixer; 5. Solid oxide fuel cell; 6. First heat exchanger; 7. Second heat exchanger; 8. Waste heat boiler; 9. Expander; 10. Condenser; 11. Booster pump; 12. Generator; 13. One-to-two multi-way valve. Detailed Implementation

[0020] The technical solutions of the present invention will now be described clearly and in detail with reference to the accompanying drawings. In the description of the embodiments of the present invention, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, in the description of the embodiments of the present invention, "multiple" refers to two or more. The terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0021] like Figure 1 , Figure 2As shown, this invention provides a solid oxide fuel cell power supply system coupled with an organic Rankine cycle, including a solid oxide fuel cell 5. The cathode inlet of the solid oxide fuel cell 5 is used to introduce air. The system also includes a power supply unit, a waste heat recovery and utilization unit, and an organic Rankine cycle unit. The power supply unit includes a steam generator 1, a first mixer 2, and a compact reformer 3 connected in sequence. The compact reformer 3 has a cold channel and a hot channel inside. The two ends of the cold channel are the reforming side inlet and the reforming side outlet, respectively. The two ends of the hot channel are the combustion side inlet and the combustion side outlet, respectively. The cold channel is connected to the first mixer and the anode inlet of the solid oxide fuel cell, respectively. The hot channel is connected to the anode outlet and the cathode outlet of the solid oxide fuel cell, respectively. The steam generator 1 generates steam. Natural gas enters the first mixer 2 and mixes with the steam from the steam generator 1 before entering the compact reformer 3 for catalytic reforming. Subsequently, it reacts with air in the solid oxide fuel cell 5 to convert chemical energy into electrical energy. The waste heat recovery and utilization unit includes a second mixer 4 connected to the solid oxide fuel cell 5 and the hot channel, respectively, and a third mixer 4 connected in sequence. A heat exchanger 6 and a second heat exchanger 7 are connected. The inlet of the second mixer 4 is connected to the anode and cathode outlets of the solid oxide fuel cell 5. The outlet of the second mixer 4 is connected to the combustion-side inlet of the compact reformer 3. The first outlet of the first heat exchanger 6 is connected to the cathode inlet of the solid oxide fuel cell 5. The first outlet of the second heat exchanger 7 is connected to the inlet of the first mixer 2. The anode exhaust gas and cathode exhaust gas of the solid oxide fuel cell 5 are mixed in the second mixer 4 and then enter the hot channel for catalytic combustion reaction to provide heat for the catalytic reforming reaction and generate combustion-side exhaust gas. The exhaust gas from the combustion side is then divided into two paths by a multi-way valve 13. One path enters the steam generator 1 to heat water and generate steam, while the other path passes through the waste heat boiler 8 and then enters the second heat exchanger 7 and the first heat exchanger 6 in sequence. Natural gas enters from the second heat exchanger 7 for preheating, and air enters from the first heat exchanger 6 for preheating. The organic Rankine cycle unit is connected to the second heat exchanger 7 and is used to recover and reuse the waste heat in the exhaust gas. That is, the exhaust gas generated on the combustion side of the compact reformer 3 is reused after heat exchange between the first heat exchanger 6 and the second heat exchanger 7.

[0022] like Figure 2 As shown, the compact reformer 3 is a plate-type microreactor with a coated wall. One side of the substrate of the compact reformer 3 is coated with a reforming catalyst to form a cold channel for catalytic reforming reaction, and the other side of the substrate of the compact reformer 3 is coated with a combustion catalyst to form a hot channel for catalytic combustion reaction.

[0023] Among them, the steam generator 1 is used to generate the steam required for the catalytic reforming reaction. Its heat source is the waste heat in the system, including the waste heat of the high-temperature gas at the cathode outlet of the solid oxide fuel cell 5 and the waste heat before preheating the combustion side tail gas of the compact reformer 3.

[0024] Among them, the anode of the solid oxide fuel cell is preferably a metal-ceramic electrode composed of nickel and yttrium oxide-stabilized zirconium oxide, which allows for the simultaneous transport of fuel, oxygen ions and electrons, thereby promoting electrochemical reactions and exhibiting relatively stable chemical properties. The cathode is preferably an alloy ceramic doped with lanthanum manganate. The materials of the anode, cathode, electrolyte and connector of the solid oxide fuel cell are selected based on conductivity, stability, compatibility, porosity and thermal expansion, and the ease of manufacturing process is also taken into consideration.

[0025] like Figure 1 As shown, the organic Rankine cycle unit includes a waste heat boiler 8, an expander 9, a condenser 10, and a booster pump 11 connected sequentially. The waste heat boiler 8 is connected to a second heat exchanger 7, and the output shaft of the expander 9 is connected to a generator 12. This unit uses an organic working fluid as the working fluid, achieving effective capture and energy conversion of the medium- and low-temperature waste heat generated during fuel cell power generation. Since the exhaust gas still has a high calorific value after preheating with air and fuel, direct emission would result in energy waste. However, by introducing the organic Rankine cycle unit composed of the waste heat boiler 8, expander 9, condenser 10, and booster pump 11, this previously unusable low-grade heat energy can be converted into usable mechanical energy for power generation, significantly improving the overall energy utilization rate of the system. Furthermore, this invention has a compact layout, facilitating integration into marine propulsion systems or distributed energy devices, expanding energy output forms without increasing additional fuel consumption, and meeting the needs of combined energy supply.

[0026] In summary, this invention integrates catalytic reforming and catalytic combustion on both sides of a compact reformer 3, achieving direct heat transfer and avoiding the integration of pre-reformers and afterburners in traditional systems. This reduces the volume occupied on board and improves thermal integration efficiency. Simultaneously, the exhaust gas from the solid oxide fuel cell 5 undergoes catalytic combustion on the combustion side of the compact reformer 3 to heat the catalytic reforming reaction, avoiding dependence on external heat sources and improving the system's energy self-sufficiency. By preheating air and natural gas through multi-stage heat exchange, some of the system's waste heat is recovered and utilized, reducing energy consumption. Furthermore, by combining an organic Rankine cycle, the waste heat of the exhaust gas, which still has utilization value after multiple heat exchanges, is deeply recovered and converted into additional electrical energy. This achieves multi-stage efficient conversion of fuel chemical energy → electrical energy → waste heat → mechanical energy → electrical energy, significantly improving overall energy utilization. It is suitable for scenarios with limited space and diverse energy needs, such as ships and islands.

[0027] like Figure 3 As shown, the present invention also provides a method for powering a solid oxide fuel cell coupled with an organic Rankine cycle, using the above system and comprising the following steps: Steam generated by steam generator 1 enters first mixer 2. Natural gas is preheated in second heat exchanger 7 and then enters first mixer 2. Steam and natural gas are mixed in first mixer 2 and then enter compact reformer 3 for catalytic reforming reaction. Subsequently, it enters solid oxide fuel cell 5 and reacts with air preheated in first heat exchanger 6 to convert chemical energy into electrical energy.

[0028] The anode exhaust gas and cathode exhaust gas of the solid oxide fuel cell 5 are mixed in the second mixer 4 and then enter the compact reformer 3 for catalytic combustion reaction to provide heat for the catalytic reforming reaction. Subsequently, they enter the first heat exchanger 6 and the second heat exchanger 7 in sequence to preheat the air and natural gas.

[0029] The exhaust gas from the combustion side enters the waste heat boiler 8 through the one-to-two multi-way valve 13. After exchanging heat with the pressurized liquid organic working fluid by the booster pump 11, it is discharged. The liquid organic working fluid becomes superheated organic working fluid vapor and enters the expander 9 to expand and do work, outputting mechanical energy to drive the generator 12 to generate electricity. After expanding and doing work, the low-pressure organic working fluid vapor enters the condenser 10 and is condensed into liquid organic working fluid, continuing the cycle.

[0030] In the first mixer 2, the molar ratio of steam to natural gas is (2.5~3.5):1. The first mixer 2 is used to uniformly mix the steam from the steam generator 1 with the natural gas preheated by the second heat exchanger 7 to form a feed gas suitable for subsequent reforming reactions. One of the key parameters of this mixing process is the molar ratio of steam to natural gas. This ratio directly affects the extent of methane steam reforming reaction in the compact reformer 3, the hydrogen yield, and the carbonization tendency of the catalyst surface. When the molar ratio is controlled within the range of (2.5~3.5):1, the water vapor content in the system is sufficient to promote the forward reaction of CH4+H2O→CO+3H2, while effectively suppressing the occurrence of side reactions such as 2CO→C+CO2 or CH4→C+2H2, thereby ensuring the high efficiency and stability of the reforming reaction. Water vapor participates in the reforming reaction as an oxidant. Too low a molar amount leads to incomplete reaction, reduced hydrogen production, and a significant increase in the risk of carbon deposition on the catalyst surface, potentially causing catalyst deactivation and channel blockage. Conversely, too much water vapor increases system energy consumption, leading to increased heat load on steam generator 1 and reduced overall energy efficiency. Therefore, limiting the molar ratio of steam to natural gas to between 2.5 and 3.5 achieves an economical balance in energy utilization while ensuring high conversion rates. For example, in one optional embodiment, this molar ratio is set to 3:1. At this temperature, the reforming reaction temperature is maintained within the range of 600°C to 650°C, achieving a methane conversion rate of over 85%, and no significant carbon deposition was observed during 100 hours of continuous operation.

[0031] In this process, steam and natural gas are mixed in the first mixer 2 and then enter the compact reformer 3 for catalytic reforming. A Ni-based catalyst is used as the catalyst for this reaction, and the catalytic reforming temperature is 600℃~650℃. Using a Ni-based catalyst means that the inner wall of the catalytic reforming channel in the compact reformer 3 is coated with a catalyst material with nickel (Ni) as the main active component. Ni-based catalysts have high methane activation capacity, good anti-carbon deposition performance, and moderate cost advantages, making them suitable for hydrocarbon steam reforming reactions under medium- and high-temperature conditions. The reforming reaction temperature of 600℃~650℃ indicates that the operating temperature range of the catalytic reforming reaction is controlled within this range. This temperature level satisfies the kinetic requirements of the Ni-based catalyst for the dissociation and adsorption of methane molecules, ensuring high CH4 conversion and H2 yield, while avoiding problems such as increased thermal stress on equipment materials, catalyst sintering and deactivation, and increased system energy consumption caused by excessively high operating temperatures. Within this temperature range, the reforming reaction rate is relatively fast, and the reaction equilibrium tends to shift towards the generation of H2 and CO. At the same time, it helps to suppress side reactions such as carbon evolution, thereby ensuring the long-term stable operation of the system.

[0032] In this embodiment, when the anode and cathode exhaust gases of the solid oxide fuel cell 5 are mixed in the second mixer 4 and then enter the compact reformer 3 for catalytic combustion, a Pt-based catalyst is used as the catalyst for the catalytic combustion reaction, and the temperature of the catalytic combustion reaction is 700℃~750℃. The Pt-based catalyst refers to a catalytic material with platinum as the main active component, typically supported on a high specific surface area ceramic or metal support, such as alumina, cerium dioxide, or honeycomb cordierite. This catalyst has excellent low-temperature ignition performance and anti-poisoning ability, and is particularly suitable for complex exhaust gas environments containing H2 and CO, as well as incompletely consumed hydrocarbon components. In this embodiment, the Pt-based catalyst is coated on the wall of the catalytic combustion channel inside the compact reformer 3 to form a catalytic combustion layer, which is used to promote the efficient oxidation reaction between the residual combustible gas in the anode exhaust gas and the residual oxygen in the cathode exhaust gas of the solid oxide fuel cell 5. The operating temperature of the catalytic combustion reaction is controlled within the range of 700℃ to 750℃. This temperature range balances reaction kinetic efficiency and system structural safety: on the one hand, this temperature range is sufficient to ensure that the Pt-based catalyst maintains high catalytic activity, achieving rapid and complete combustion of combustible components such as H2 and CO in the exhaust gas. On the other hand, it avoids problems such as thermal creep and oxidation failure of the metal substrate or sealing materials due to excessively high temperatures, thereby ensuring the long-term stability of the compact reformer 3. In addition, this temperature range matches the heat recovery requirements of the subsequent first heat exchanger 6 and second heat exchanger 7, which is conducive to realizing the cascade utilization of heat.

[0033] The organic Rankine cycle unit uses an organic working fluid, which is either saturated or superheated at the waste heat boiler outlet. The operating parameters of the organic Rankine cycle unit, such as the evaporation pressure, condensation pressure, superheat, and subcooling of the organic working fluid, need to be comprehensively optimized based on the specific thermophysical properties of the selected working fluid and the actual temperature of the exhaust gas at the inlet of the waste heat boiler. The aim is to maximize net power output and system efficiency. The organic working fluid is R245fa or a non-azeotropic mixture of R245fa and R1234yf in a specific ratio. For example, for working fluid R245fa, at a given exhaust gas temperature, there exists an optimal evaporation pressure that maximizes the cycle's net power output. The optimization process can be completed through thermodynamic modeling and simulation to ensure the system operates near its optimal operating point.

[0034] When the low-pressure organic working fluid vapor, after expanding and doing work, enters the condenser 10 and condenses into a liquid organic working fluid, it outputs cold energy.

[0035] Working principle: Steam generated by steam generator 1 enters first mixer 2. Natural gas is preheated in second heat exchanger 7 and then enters first mixer 2. Steam and natural gas are mixed in first mixer 2 with a molar ratio of steam to natural gas of (2.5~3.5):1. After mixing, it enters compact reformer 3 for catalytic reforming reaction, and then enters solid oxide fuel cell 5 to react with air preheated in first heat exchanger 6 to convert chemical energy into electrical energy.

[0036] The anode exhaust gas and cathode exhaust gas of the solid oxide fuel cell 5 are mixed in the second mixer 4 and then enter the compact reformer 3 for catalytic combustion reaction, providing heat for the catalytic reforming reaction. Subsequently, they enter the first heat exchanger 6 and the second heat exchanger 7 in sequence to preheat the air and natural gas.

[0037] After heat exchange in the second heat exchanger 7, the exhaust gas enters the waste heat boiler 8 and exchanges heat with the pressurized liquid organic working fluid in the booster pump 11 before being discharged. The liquid organic working fluid becomes superheated organic working fluid vapor and enters the expander 9 to expand and do work, outputting mechanical energy to drive the generator 12 to generate electricity. After expanding and doing work, the low-pressure organic working fluid vapor enters the condenser 10 and condenses into liquid organic working fluid, continuing the cycle.

[0038] It is understood that this invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this invention. Furthermore, under the teachings of this invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this invention. Therefore, this invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this invention are within the protection scope of this invention.

Claims

1. A solid oxide fuel cell power supply system coupled with an organic Rankine cycle, comprising a solid oxide fuel cell, wherein the cathode inlet is used for introducing air, characterized in that, Also includes: The power supply unit includes a steam generator, a first mixer, and a compact reformer connected in sequence. The compact reformer has a cold channel and a hot channel inside. The cold channel is connected to the first mixer and the anode inlet of the solid oxide fuel cell, respectively. The hot channel is connected to the anode outlet and the cathode outlet of the solid oxide fuel cell. The steam generator is used to generate steam. Natural gas enters the first mixer and mixes with the steam from the steam generator before entering the cold channel of the compact reformer for catalytic reforming. Subsequently, it reacts with air in the solid oxide fuel cell to convert chemical energy into electrical energy. The waste heat recovery and utilization unit includes a second mixer connected to a solid oxide fuel cell and a hot channel, and a first heat exchanger and a second heat exchanger connected in sequence. The first heat exchanger is connected to the solid oxide fuel cell, and the second heat exchanger is connected to the first mixer. The anode exhaust gas and cathode exhaust gas of the solid oxide fuel cell are mixed in the second mixer and then enter the hot channel for catalytic combustion reaction to provide heat for catalytic reforming reaction and generate combustion-side exhaust gas. Then, the combustion-side exhaust gas is divided into two paths by a one-to-two multi-way valve. One path enters the steam generator to heat water to generate steam, and the other path enters the second heat exchanger and the first heat exchanger in sequence after passing through the waste heat boiler. Natural gas enters from the second heat exchanger for preheating, and air enters from the first heat exchanger for preheating. The organic Rankine cycle unit, connected to the thermal passage of the compact reformer, is used to reuse the residual heat in the exhaust gas.

2. The solid oxide fuel cell power supply system coupled with an organic Rankine cycle according to claim 1, characterized in that, The organic Rankine cycle unit includes a waste heat boiler, an expander, a condenser, and a booster pump connected in sequence. The waste heat boiler is connected to a second heat exchanger, and the output shaft of the expander is connected to a generator.

3. A solid oxide fuel cell power supply system coupled with an organic Rankine cycle according to claim 1, characterized in that, The compact reformer is a coated plate microreactor. One side of the substrate of the compact reformer is coated with a reforming catalyst to form a cold channel, and the other side of the substrate of the compact reformer is coated with a combustion catalyst to form a hot channel.

4. A method for powering a solid oxide fuel cell coupled with an organic Rankine cycle, characterized in that, The system described in claim 2 includes the following steps: Steam generated by the steam generator enters the first mixer. Natural gas is preheated in the second heat exchanger and then enters the first mixer. The steam and natural gas are mixed in the first mixer and then enter the compact reformer for catalytic reforming. Subsequently, it enters the solid oxide fuel cell and reacts with the air preheated in the first heat exchanger to convert chemical energy into electrical energy. After the anode and cathode exhaust gases of the solid oxide fuel cell are mixed in the second mixer, they enter the compact reformer for catalytic combustion reaction to provide heat for the catalytic reforming reaction and generate combustion-side exhaust gas. Then, the combustion-side exhaust gas is divided into two paths by a one-to-two multi-way valve. One path enters the steam generator to heat water and generate steam, and the other path passes through the waste heat boiler and enters the second heat exchanger and the first heat exchanger in sequence to preheat natural gas and air. The exhaust gas from the combustion side enters the waste heat boiler and exchanges heat with the pressurized liquid organic working fluid from the booster pump before being discharged. The liquid organic working fluid becomes superheated organic working fluid steam, which enters the expander to expand and do work, outputting mechanical energy to drive the generator to generate electricity. After expanding and doing work, the low-pressure organic working fluid steam enters the condenser to condense and becomes liquid organic working fluid, continuing the cycle.

5. A method for powering a solid oxide fuel cell coupled with an organic Rankine cycle according to claim 4, characterized in that, When the steam and natural gas are mixed in the first mixer, the molar ratio of steam to natural gas is (2.5~3.5):

1.

6. A method for powering a solid oxide fuel cell coupled with an organic Rankine cycle according to claim 3, characterized in that, The steam and natural gas are mixed in the first mixer and then enter the cold channel of the compact reformer for catalytic reforming.

7. A method for powering a solid oxide fuel cell coupled with an organic Rankine cycle according to claim 3, characterized in that, The anode exhaust gas and cathode exhaust gas of the solid oxide fuel cell are mixed in the second mixer and then enter the hot channel of the compact reformer for catalytic combustion reaction.

8. A method for powering a solid oxide fuel cell coupled with an organic Rankine cycle according to claim 4, characterized in that, The organic Rankine cycle unit uses an organic working fluid, which is saturated or superheated at the outlet of the waste heat boiler.

9. A method for powering a solid oxide fuel cell coupled with an organic Rankine cycle according to claim 8, characterized in that, The organic working medium is R245fa or a non-azeotropic mixture of R245fa and R1234yf in a certain proportion.

Images