CN111900432A - Solid oxide fuel cell system, power-cooling combined supply system and method thereof - Google Patents

Abstract

The invention belongs to the field of active circulation and provides a solid oxide fuel cell system, a power and cooling combined supply system and a method thereof. The solid oxide fuel cell system comprises a solid oxide fuel cell, a combustion chamber, a gas turbine, a first mixer, a second mixer and a pre-reformer; the cathode and the anode of the solid oxide fuel cell are both connected with a combustion chamber, the heat energy output by the combustion chamber provides energy for a gas turbine, and gas exhausted by the gas turbine is used as a heat source for preheating air, methane and water; the first mixer is used for mixing the gas extracted from the cathode output end of the solid oxide fuel cell and the preheated air, and then conveying the gas to the cathode input end of the solid oxide fuel cell; the second mixer is used for extracting gas from the anode output end of the solid oxide fuel cell and preheated methane and water, and then conveying the gas, the preheated methane and the water to the anode input end of the solid oxide fuel cell through the pre-reformer.

Description

Solid oxide fuel cell system, power-cooling combined supply system and method thereof

technical field

The invention belongs to the field of active circulation, and in particular relates to a solid oxide fuel cell system, a power-cooling combined supply system and a method thereof.

Background technique

The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

Solid oxide fuel cell (Solid Oxide Fuel Cell, SOFC for short) belongs to the third-generation fuel cell, which is an all-solid-state fuel cell that directly converts chemical energy stored in fuel and oxidant into electrical energy efficiently and environmentally friendly at medium and high temperature. Chemical power plant. It is generally considered to be a fuel cell that will be widely used in the future along with the proton exchange membrane fuel cell (PEMFC). A general SOFC power generation system includes a fuel processing unit, a fuel cell power generation unit, and an energy recovery unit. Usually, the air is compressed by the compressor, enters the preheater to be preheated after overcoming the system resistance, and then passes into the cathode of the battery. After the natural gas is compressed by the compressor, it overcomes the resistance of the system and enters the mixer, where it is mixed with the superheated steam generated in the steam generator. The cathode and anode gases undergo an electrochemical reaction in the battery. When the battery emits electricity, the heat generated by the electrochemical reaction heats the unreacted cathode and anode gases. The unreacted gas of the anode and the residual oxidant of the cathode are passed into the burner for combustion. The high-temperature gas produced by the combustion is not only used to preheat the fuel and air, but also provides the heat required by the steam generator. The thermal energy of the combustion product after passing through the steam generator is still valuable, and can be further utilized by providing hot water or heating through the waste heat recovery device.

The inventors found that the use of an internally reformed SOFC (solid oxide fuel cell) stack will cause a very uneven temperature distribution inside the stack and a large temperature gradient, which will cause uneven stress to the stack material and rupture; The SOFC fuel utilization rate of the return mode is low, so that the mass flow of air and fuel will be larger, resulting in larger power consumption of the compressor, and at the same time, it will increase the exergy loss of the preheater; When the gas temperature is lowered, the available bottom circulation is lower than the exergy. The inventor also found that the traditional ammonia water power cycle or ammonia water refrigeration cycle can only obtain a single demand, and even if _two cycles are used as low-temperature waste heat utilization at the same time, the equipment will increase and the investment cost will increase; When the condenser is used to exhaust heat, to obtain greater thermal efficiency, the condenser will exhaust a large amount of heat and cause a large amount of exergy loss, and the economy is not high.

SUMMARY OF THE INVENTION

In order to solve the above problems, a first aspect of the present invention provides a solid oxide fuel cell system, which adopts a pumping and recirculation method, which can improve the fuel and oxygen utilization rate of the solid oxide fuel cell, and reduce the mass flow of air and fuel, Reduce compressor power consumption.

In order to achieve the above object, the present invention adopts the following technical solutions:

A solid oxide fuel cell system, comprising a solid oxide fuel cell, a combustor, a gas turbine, a first mixer, a second mixer, and a pre-reformer;

The cathode and anode of the solid oxide fuel cell are connected to the combustion chamber, the heat energy output from the combustion chamber provides energy for the gas turbine, and the gas discharged from the gas turbine is used as a heat source to preheat air, methane and water;

The first mixer is used to mix the gas extracted from the cathode output end of the solid oxide fuel cell and the preheated air, and then transport it to the cathode input end of the solid oxide fuel cell;

The second mixer is used for the gas extracted from the anode output of the SOFC and the preheated methane and water before being sent to the anode input of the SOFC through the pre-reformer.

As an embodiment, a regenerator is also connected in series between the second mixer and the pre-reformer, and the gas extracted from the anode output end of the solid oxide fuel cell is also sent to the second mixer through the regenerator.

In this embodiment, the regenerator can be used to increase the temperature of the gas extracted from the anode output end of the solid oxide fuel cell, thereby increasing the temperature of the mixed gas in the second mixer, and finally entering the combustion through the anode input end of the solid oxide fuel cell room to improve fuel utilization.

As an embodiment, the regenerator is also connected to a flow divider, and the flow divider is used to divide the gas extracted from the anode output end of the solid oxide fuel cell into two parts after heat exchange in the heat exchanger, and a part is sent to the first Two mixers, the other part is sent to the combustion chamber.

The effect of this technical solution is: when the addition of the splitter can also affect the fuel and water quality according to the change of the SOFC working temperature, the split ratio of the splitter can still be adjusted so that the flow rate before entering the heat exchanger and the reformer can be adjusted. The gases have a good temperature match so that there is no linear increase in temperature that occurs too much or too little without the split ratio.

As an embodiment, the gas turbine outlet is also connected in series with the first preheater, the second preheater and the third preheater, so that the gas discharged from the gas turbine outlet is used as the heat source of the corresponding preheater for the respective preheaters. Preheat pressurized air, pressurized methane and water.

The effect of this technical solution is: preheating can also reduce the temperature of the inlet of the mixture of fuel and water, which reduces the heat exchange of the preheater, increases the temperature of the exhaust gas used for the bottoming cycle, and increases the bottoming temperature. The exergy-availability ratio of the cycle.

A second aspect of the present invention provides a working method of a solid oxide fuel cell system, comprising:

Part of the gas discharged from the cathode of the solid oxide fuel cell is sent to the combustion chamber, and the other part is sent to the first mixer; part of the gas discharged from the anode output end of the solid oxide fuel cell is sent to the combustion chamber, and the other part is sent to the second mixer device;

The heat energy output from the combustion chamber provides energy for the gas turbine, and the gas discharged from the gas turbine outlet is used as a heat source to preheat the pressurized air, pressurized methane and water respectively;

Utilize the first mixer to mix the preheated air and the gas extracted from the cathode output end of the solid oxide fuel cell, and deliver the mixed gas to the cathode input end of the solid oxide fuel cell;

A second mixer is used to mix the preheated methane, the preheated water, and the gas extracted from the anode output of the SOFC, and deliver the mixed gas to the anode of the SOFC through the pre-reformer input.

A third aspect of the present invention provides a combined power and cooling system, which includes a supercritical CO2 cycle system, a Gauss-Wami cycle system, an LNG (liquefied natural gas) cold energy recovery and fuel supply system, and the above-mentioned solid oxides fuel cell system;

The LNG cold energy recovery and fuel supply system is used for the output methane and supplied to the solid oxide fuel cell system; the gas discharged from the gas turbine outlet in the solid oxide fuel cell system is also used as heat exchange in the supercritical CO ₂ circulating system The heat source output from the heat exchanger in the supercritical CO ₂ cycle system enters the boiler and superheater of the Gauss-Wami cycle system in turn and exchanges heat with the working fluid, so that the heat-exchanged gas is discharged under the atmospheric pressure Gauss-Wami Circulatory system.

As an embodiment, the Gauss-Wami cycle system includes an absorber, and the absorber is connected to a pump; after the basic working fluid in the absorber is pressurized by the pump, it sequentially enters the regenerative heat exchanger and the boiler for exchange respectively. heat and heating; the input end of the boiler is connected to the heat source output by the heat exchanger in the supercritical CO ₂ circulation system, and the output end of the boiler is also connected to the superheater; the basic working fluid after heat exchange is heated by the boiler to generate saturated steam and transported to the refined The distillation column conducts distillation to obtain saturated steam at the top of the column; the absorber is also communicated with the evaporator and the refrigeration heat exchanger respectively, and the liquid in the absorber also absorbs the steam sent from the evaporator and the refrigeration heat exchanger;

The top of the rectification tower is connected with the superheater and the ejector respectively, and a part of the saturated steam discharged from the top of the rectification tower is transferred to the superheater for superheating, and then enters the turbine for expansion work to obtain the spent steam, and finally the spent steam is exhausted. The steam enters the refrigeration heat exchanger to absorb heat and refrigerate; another part of the saturated steam enters the ejector for absorption-injection cooling, and the liquid at the outlet of the ejector enters the condenser for constant pressure condensation into a saturated solution, and then enters into a saturated solution after being throttled by the first throttle valve. Evaporative refrigeration in the evaporator; part of the saturated steam at the outlet of the evaporator is ejected by the ejector, and another part of the saturated steam is fed back to the absorber.

The advantage of the above technical solution is that the absorption-ejection coupled refrigeration cycle is adopted, and the Goswami cycle and the injection refrigeration cycle are coupled and integrated to increase the circulating refrigeration capacity, which can not only ensure the process of the single-effect absorption refrigerator, The advantages of simple equipment can also improve its cooling coefficient, so that the overall performance of the system can be improved.

As an embodiment, the bottom of the boiler is also communicated with the regenerative heat exchanger through a first pipe, so as to send a part of the liquid in the boiler to the regenerative heat exchanger for heat exchange; The second pipe is communicated with the absorber, and the bottom of the rectification tower is communicated with the second pipe through the third pipe, and the second pipe is used to mix the heat-exchanged liquid with the liquid in the third pipe and send it to the Absorber.

As an embodiment, the supercritical _CO2 circulation system includes a supercritical _CO2 heat exchanger, a supercritical _CO2 turbine and a supercritical CO2 regenerator; the supercritical _CO2 heat exchanger is used for utilizing the gas turbine outlet in the SOFC system The exhaust gas exchanges heat with the CO ₂ fluid, and after the heat exchange, a high-temperature and high-pressure CO ₂ fluid is generated. After doing work in the supercritical CO ₂ turbine, it enters the supercritical CO ₂ regenerator to heat the high-pressure and low-temperature CO ₂ fluid; from The fluid from the supercritical _CO2 regenerator is condensed by the condenser of the LNG cold energy recovery and fuel supply system, and then enters the pump, pressurized and sent to the supercritical _CO2 regenerator for heating, and finally enters the supercritical _CO2 heat exchanger Exchange heat with the heat source to complete the cycle.

A fourth aspect of the present invention provides a working method of a power-cooling combined supply system, comprising:

The methane output from the LNG cold energy recovery and fuel supply system is supplied to the solid oxide fuel cell system;

The gas discharged from the gas turbine outlet in the solid oxide fuel cell system is used as the heat source of the heat exchanger in the supercritical _CO2 cycle system;

The heat source output by the heat exchanger in the supercritical CO ₂ cycle system enters the boiler and superheater of the Gauss-Wami cycle system in turn and exchanges heat with the working medium, so that the heat-exchanged gas is discharged from the Gauss-Wami cycle system at atmospheric pressure.

The beneficial effects of the present invention are:

(1) The solid oxide fuel cell system of the present invention adopts the external reformation of the internal temperature distribution of the stack to be relatively uniform, so as to avoid the uneven stress of the stack material and the rupture of the stack material caused by the uneven temperature distribution.

(2) The solid oxide fuel cell system of the present invention adopts the SOFC fuel and oxygen utilization rate of the pumping and recirculation method, which reduces the mass flow of air and fuel, reduces the power consumption of the compressor, and reduces the fire of the preheater. Use loss.

(3) The anode extraction of the solid oxide fuel cell system of the present invention to preheat the mixture before the external reformer can also reduce the temperature of the inlet of the mixture of fuel and water, which reduces the replacement of the preheater. The heat increases the exhaust gas temperature for the bottoming cycle, and the available specific exergy of the bottoming cycle also increases; and the addition of a flow divider can also have a good effect on the fuel and water quality according to the SOFC operating temperature. When the split ratio is used, the split ratio of the splitter can still be adjusted so that the gas before entering the heat exchanger and the reformer has a good temperature match, so that the temperature linearly increases too much or too little when the split ratio is not added. .

(4) The combined power and cooling system of the present invention increases the temperature of the exhaust gas used for the bottoming cycle at the same time, and the available power of the bottoming cycle is higher than that of the exergy, which can generate greater specific work.

(5) The Gauss-Wami cycle in the power-cooling combined supply system of the present invention can not only perform work but also cool at the same time, and the ratio can also be adjusted according to the actual situation, and the system structure of using an ejector for ejection instead of a circulating pump can also be used. The equipment investment is relatively small.

(6) In the power-cooling combined supply system of the present invention, LNG is used to recover the supercritical CO2 condenser heat, which can not only recover the cooling energy of LNG and obtain high thermal efficiency in the circulation, but also reduce the exergy loss of the condenser and improve the circulation. economical.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

FIG. 1 is a schematic structural diagram of a SOFC system according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a SOFC power-cooling co-generation system based on external reforming according to an embodiment of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments.

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

In the present invention, terms such as "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "side", "bottom", etc. The orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only a relational word determined for the convenience of describing the structural relationship of each component or element of the present invention, and does not specifically refer to any component or element in the present invention, and should not be construed as a reference to the present invention. Invention limitations.

In the present invention, terms such as "fixed connection", "connected", "connected", etc. should be understood in a broad sense, indicating that it can be a fixed connection, an integral connection or a detachable connection; it can be directly connected, or through the middle media are indirectly connected. For the relevant scientific research or technical personnel in the field, the specific meanings of the above terms in the present invention can be determined according to the specific situation, and should not be construed as a limitation of the present invention.

As shown in FIG. 1 , the solid oxide fuel cell system of this embodiment includes a solid oxide fuel cell, a combustion chamber, a gas turbine, a first mixer, a second mixer, and a pre-reformer;

The cathode and anode of the solid oxide fuel cell are connected to the combustion chamber. The heat energy output from the combustion chamber provides energy for the gas turbine. The gas discharged from the gas turbine outlet is used as a heat source to preheat the pressurized air, pressurized methane and water, respectively. ;

The first mixer is used to mix the preheated air and the gas extracted from the cathode output end of the solid oxide fuel cell, and deliver the mixed gas to the cathode input end of the solid oxide fuel cell;

The second mixer is used to mix the preheated methane, the preheated water, and the gas extracted from the anode output of the SOFC, and deliver the mixed gas to the anode of the SOFC through the pre-reformer input.

As shown in FIG. 1 , a regenerator is also connected in series between the second mixer and the pre-reformer, and the gas extracted from the anode output end of the solid oxide fuel cell is also sent to the second mixer through the regenerator. In this embodiment, the regenerator can be used to increase the temperature of the gas extracted from the anode output end of the solid oxide fuel cell, thereby increasing the temperature of the mixed gas in the second mixer, and finally entering the combustion through the anode input end of the solid oxide fuel cell room to improve fuel utilization.

In a specific implementation, the regenerator is also connected to a flow divider, and the flow divider is used to divide the gas extracted from the anode output end of the solid oxide fuel cell into two parts after heat exchange by the heat regenerator, and one part is sent to the second mixer, and the other part is sent to the combustion chamber.

The effect of this technical solution is: when the addition of the splitter can also affect the fuel and water quality according to the change of the SOFC working temperature, the split ratio of the splitter can still be adjusted so that the flow rate before entering the heat exchanger and the reformer can be adjusted. The gases have a good temperature match so that there is no linear increase in temperature that occurs too much or too little without the split ratio.

As a specific embodiment, the gas turbine outlet is also connected in series with the first preheater, the second preheater and the third preheater, so that the gas discharged from the gas turbine outlet is used as the heat source of the corresponding preheater for Preheat pressurized air, pressurized methane, and water, respectively. The effect of this technical solution is: preheating can also reduce the temperature of the inlet of the mixture of fuel and water, which reduces the heat exchange of the preheater, increases the temperature of the exhaust gas used for the bottoming cycle, and increases the bottoming temperature. The exergy-availability ratio of the cycle.

The working method of a kind of SOFC system of the present embodiment, comprises:

Part of the gas discharged from the cathode of the solid oxide fuel cell is sent to the combustion chamber, and the other part is sent to the first mixer; part of the gas discharged from the anode output end of the solid oxide fuel cell is sent to the combustion chamber, and the other part is sent to the second mixer device;

The heat energy output from the combustion chamber provides energy for the gas turbine, and the gas discharged from the gas turbine outlet is used as a heat source to preheat the pressurized air, pressurized methane and water respectively;

Utilize the first mixer to mix the preheated air and the gas extracted from the cathode output end of the solid oxide fuel cell, and deliver the mixed gas to the cathode input end of the solid oxide fuel cell;

A second mixer is used to mix the preheated methane, the preheated water, and the gas extracted from the anode output of the SOFC, and deliver the mixed gas to the anode of the SOFC through the pre-reformer input.

In the SOFC system of this embodiment, the internal temperature distribution of the stack using external reformation is relatively uniform, which prevents the stack material from cracking due to uneven stress caused by uneven temperature distribution.

The SOFC system of this embodiment adopts the SOFC pumping and recirculation method with high utilization rate of fuel and oxygen, which reduces the mass flow of air and fuel, reduces the power consumption of the compressor, and at the same time reduces the exergy loss of the preheater.

The anode extraction of the SOFC system of this embodiment to preheat the mixture before the external reformer can also reduce the temperature of the inlet of the mixture of fuel and water, which reduces the heat exchange of the preheater, so that the The exhaust gas temperature of the bottom cycle increases, and the available ratio of the bottom cycle is also increased; and the addition of the diverter can also adjust the diversion according to the influence of the SOFC working temperature on the fuel and water quality. The split ratio of the heat exchanger allows a good temperature match of the gas before entering the heat exchanger and the reformer, so that the linear temperature increase will not be too much or too little when the split ratio is not added.

Embodiment 2

As shown in FIG. 2 , the SOFC power-cooling combined supply system based on external reforming of this embodiment includes a supercritical CO ₂ cycle system, a Gauss-Wami cycle system, an LNG cold energy recovery and a fuel supply system and the first embodiment. The SOFC system described;

The LNG cold energy recovery and fuel supply system is used for the output methane and supplied to the SOFC system; the gas discharged from the gas turbine outlet in the SOFC system is also used as the heat source of the heat exchanger in the supercritical CO ₂ circulating system; the supercritical CO ₂ The heat source output from the heat exchanger in the circulation system enters the boiler and superheater of the Gauss-Wami circulation system in turn and exchanges heat with the working medium, so that the heat-exchanged gas is discharged from the Gauss-Wami circulation system at atmospheric pressure.

In a specific implementation, the Gauss-Wami cycle system includes an absorber, and the absorber is connected to a pump; after the basic working fluid in the absorber is pressurized by the pump, it sequentially enters the regenerative heat exchanger and the boiler for heat exchange respectively. and heating; the input end of the boiler is connected to the heat source output by the heat exchanger in the supercritical CO ₂ circulation system, and the output end of the boiler is also connected to the superheater; the basic working fluid after heat exchange is heated by the boiler to generate saturated steam and transmitted to the rectification distillation The tower is distilled to obtain saturated steam at the top of the tower; the absorber is also communicated with the evaporator and the refrigeration heat exchanger respectively, and the liquid in the absorber also absorbs the steam sent from the evaporator and the refrigeration heat exchanger;

The top of the rectification tower is connected with the superheater and the ejector respectively, and a part of the saturated steam discharged from the top of the rectification tower is transferred to the superheater for superheating, and then enters the turbine for expansion work to obtain the spent steam, and finally the spent steam is exhausted. The steam enters the refrigeration heat exchanger to absorb heat and refrigerate; another part of the saturated steam enters the ejector for absorption-injection cooling, and the liquid at the outlet of the ejector enters the condenser for constant pressure condensation into a saturated solution, and then enters into a saturated solution after being throttled by the first throttle valve. Evaporative refrigeration in the evaporator; part of the saturated steam at the outlet of the evaporator is ejected by the ejector, and another part of the saturated steam is fed back to the absorber.

The advantage of the above technical solution is that the absorption-ejection type coupled refrigeration cycle is adopted, and the Goswami cycle and the injection type refrigeration cycle are coupled and integrated to increase the circulating refrigeration capacity, which can not only ensure the advantages of the single-effect absorption type absorption refrigerator with simple process and simple equipment, It can also increase its cooling coefficient, thereby improving the overall performance of the system.

As a specific embodiment, the bottom of the boiler is also communicated with the regenerative heat exchanger through a first pipe, for sending a part of the liquid in the boiler to the regenerative heat exchanger for heat exchange; the regenerative heat exchanger The second pipe is connected to the absorber, and the bottom of the rectification tower is connected to the second pipe through a third pipe. The second pipe is used to mix the heat-exchanged liquid with the liquid in the third pipe and send it to the to the absorber.

As shown in Figure 2, the supercritical _CO2 cycle system includes a supercritical _CO2 heat exchanger, a supercritical _CO2 turbine and a supercritical CO2 regenerator; the supercritical _CO2 heat exchanger is used to utilize the gas turbine outlet in the SOFC system The exhaust gas exchanges heat with the CO ₂ fluid, and after the heat exchange, a high-temperature and high-pressure CO ₂ fluid is generated. After doing work in the supercritical CO ₂ turbine, it enters the supercritical CO ₂ regenerator to heat the high-pressure and low-temperature CO ₂ fluid; from The fluid from the supercritical _CO2 regenerator is condensed by the condenser of the LNG cold energy recovery and fuel supply system, and then enters the pump, pressurized and sent to the supercritical _CO2 regenerator for heating, and finally enters the supercritical _CO2 heat exchanger Exchange heat with the heat source to complete the cycle.

In a specific implementation, a second throttle valve is provided on the third pipeline. The flow rate of the liquid delivered to the absorber is adjusted by controlling the opening degree of the second throttle valve arranged on the third pipeline.

Specifically, a pressure sensor is also arranged in the absorber, the pressure sensor is connected to a controller, and the controller is connected to a pump. The pressure in the absorber is detected by a pressure sensor and sent to the controller, and the control controls the operating frequency of the pump according to the received pressure.

In this embodiment, the first throttle valve is a solenoid valve, and the first throttle valve is connected to the controller. In this way, manual adjustment is avoided, and the opening degree of the first throttle valve can be accurately adjusted by the controller. The second throttle valve is a solenoid valve, and the second throttle valve is connected to the controller. In this way, manual adjustment is avoided, and the opening degree of the second throttle valve can be accurately adjusted by the controller.

The working method of the SOFC power-cooling combined supply system based on external reformation of the present embodiment includes:

Methane output from the LNG cold energy recovery and fuel supply system is supplied to the SOFC system;

The gas discharged from the gas turbine outlet in the SOFC system is used as the heat source of the heat exchanger in the supercritical CO2 cycle system;

The heat source output from the heat exchanger in the supercritical CO2 cycle system enters the boiler and the superheater of the Gauss-Wami cycle system in turn and exchanges heat with the working medium, so that the heat-exchanged gas is discharged from the Gauss-Wami cycle system at atmospheric pressure.

The SOFC power-cooling co-generation system based on external reforming in this embodiment simultaneously increases the temperature of the exhaust gas used for the bottoming cycle, and the usable ratio of the exergy to the bottoming cycle is increased, which can generate greater specific work.

The Gauss-Wami cycle in the SOFC power-cooling combined supply system based on external reforming in this embodiment can not only perform work but also cool at the same time, the ratio can also be adjusted according to the actual situation, and the ejector is used for ejection instead of the circulating pump, etc. The system structure also makes the equipment investment relatively small.

In the SOFC combined power and cooling system based on external reforming of the present embodiment, LNG is used to recover the supercritical CO2 condenser exhaust heat, which can not only recover the cooling energy of LNG and obtain high thermal efficiency in the circulation, but also reduce the exergy of the condenser. damage and improve circular economy.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A solid oxide fuel cell system comprising a solid oxide fuel cell, a combustor, a gas turbine, a first mixer, a second mixer, and a pre-reformer;

the cathode and the anode of the solid oxide fuel cell are both connected with a combustion chamber, the heat energy output by the combustion chamber provides energy for a gas turbine, and gas exhausted by the gas turbine is used as a heat source for preheating air, methane and water;

the first mixer is used for mixing the gas extracted from the cathode output end of the solid oxide fuel cell and the preheated air, and then conveying the gas to the cathode input end of the solid oxide fuel cell;

the second mixer is used for extracting gas from the anode output end of the solid oxide fuel cell and preheated methane and water, and then conveying the gas, the preheated methane and the water to the anode input end of the solid oxide fuel cell through the pre-reformer.

2. The solid oxide fuel cell system of claim 1, wherein a regenerator is further connected in series between the second mixer and the pre-reformer, and wherein the gas extracted at the anode output of the solid oxide fuel cell is further sent to the second mixer via the regenerator.

3. The solid oxide fuel cell system of claim 2, wherein the regenerator is further coupled to a splitter for splitting the gas extracted at the anode output of the solid oxide fuel cell into two portions, one portion being delivered to the second mixer and the other portion being delivered to the combustion chamber after heat exchange by the regenerator.

4. The solid oxide fuel cell system of claim 1, wherein the gas turbine outlet is further connected in series with a first preheater, a second preheater, and a third preheater in that order, such that gas discharged from the gas turbine outlet serves as a heat source for the respective preheaters for preheating the pressurized air, the pressurized methane, and the water, respectively.

5. A method of operating a solid oxide fuel cell system as claimed in any of claims 1 to 4, comprising:

one part of gas discharged from a cathode of the solid oxide fuel cell is sent into a combustion chamber, and the other part of gas is sent to a first mixer; one part of gas discharged from the anode output end of the solid oxide fuel cell is sent into the combustion chamber, and the other part of the gas is sent to the second mixer;

the heat energy output by the combustion chamber provides energy for the gas turbine, and gas exhausted from the outlet of the gas turbine is used as a heat source for preheating the pressurized air, the pressurized methane and the pressurized water respectively;

mixing the preheated air and the gas extracted from the cathode output end of the solid oxide fuel cell by using a first mixer, and conveying the mixed gas to the cathode input end of the solid oxide fuel cell;

and mixing the preheated methane, the preheated water and the gas extracted from the anode output end of the solid oxide fuel cell by using a second mixer, and conveying the mixed gas to the anode input end of the solid oxide fuel cell through a prereformer.

6. The power-cooling combined supply system is characterized by comprising supercritical CO₂A recycle system, a gaswami recycle system, an LNG cold energy recovery and fuel supply system and a solid oxide fuel cell system as claimed in any one of claims 1 to 4;

the LNG cold energy recovery and fuel supply system is used for exported methane and supplying the methane to the solid oxide fuel cell system; the gas discharged from the outlet of the gas turbine in the solid oxide fuel cell system is also used as supercritical CO₂A heat source of a heat exchanger in the circulation system; supercritical CO₂And a heat source output by the heat exchanger in the circulating system sequentially enters a boiler and a superheater of the Gaussian watt-meter circulating system and exchanges heat with the working medium, so that the gas after heat exchange is discharged out of the Gaussian watt-meter circulating system under atmospheric pressure.

7. The combined power and cooling system of claim 6 wherein the Gaussian watt cycle system includes an absorber connected to a pump; after being pressurized by a pump, basic working fluid in the absorber sequentially enters a regenerative heat exchanger and a boiler to exchange heat and heat respectively; boiler input and supercritical CO₂The heat source output by the heat exchanger in the circulating system is connected, and the output end of the boiler is also connected withThe superheater is connected; heating the heat-exchanged basic working solution by a boiler to generate saturated steam, transmitting the saturated steam to a rectifying tower for distillation, and obtaining the saturated steam at the tower top; the absorber is also respectively communicated with the evaporator and the refrigeration heat exchanger, and the liquid in the absorber also absorbs the steam transmitted from the evaporator and the refrigeration heat exchanger;

the top of the rectifying tower is respectively communicated with a superheater and an ejector, a part of saturated steam discharged from the top of the rectifying tower is transmitted to the superheater for superheating, the superheated steam enters a turbine for expansion work to obtain dead steam, and finally the dead steam enters a refrigeration heat exchanger for heat absorption and refrigeration; the other part of the saturated steam enters an ejector for absorption-ejection refrigeration, the liquid at the outlet of the ejector enters a condenser for constant pressure condensation to form saturated solution, and then enters an evaporator for evaporation refrigeration after being throttled by a first throttle valve; and one part of saturated steam at the outlet of the evaporator is injected by the ejector, and the other part of saturated steam is fed back and conveyed to the absorber.

8. The combined power and cooling system according to claim 7, wherein the bottom of the boiler is further communicated with the regenerative heat exchanger through a first pipeline, and is used for sending a part of liquid in the boiler to the regenerative heat exchanger for heat exchange; the regenerative heat exchanger is communicated with the absorber through a second pipeline, the tower bottom of the rectifying tower is communicated with the second pipeline through a third pipeline, and the second pipeline is used for mixing the liquid after heat exchange with the liquid in the third pipeline and then sending the mixed liquid to the absorber.

9. The power-cooling combined supply system of claim 6, wherein the supercritical CO is₂The recycle system comprises supercritical CO₂Heat exchanger, supercritical CO₂Transparent and supercritical CO₂A heat regenerator; supercritical CO2 heat exchanger for utilizing gas discharged from outlet of gas turbine in SOFC system to CO₂The fluid exchanges heat and generates high-temperature and high-pressure CO after heat exchange₂Fluid in supercritical CO₂After doing work in the turbine, the gas enters supercritical CO₂Regenerator for high-pressure low-temperature CO₂Heating the fluid; from supercritical CO₂The fluid from the heat regenerator enters a pump after being condensed by a condenser of an LNG cold energy recovery and fuel supply system, and is pressurized and sent to supercritical CO₂Heating by a heat regenerator, and finally introducing supercritical CO₂The heat exchanger exchanges heat with a heat source to complete circulation.

10. A method of operating a combined power and cooling system according to any one of claims 6 to 9, comprising:

methane output by the LNG cold energy recovery and fuel supply system is supplied to the solid oxide fuel cell system;

gas discharged from the outlet of a gas turbine in a solid oxide fuel cell system is used as supercritical CO₂A heat source of a heat exchanger in the circulation system;

supercritical CO₂And a heat source output by the heat exchanger in the circulating system sequentially enters a boiler and a superheater of the Gaussian watt-meter circulating system and exchanges heat with the working medium, so that the gas after heat exchange is discharged out of the Gaussian watt-meter circulating system under atmospheric pressure.

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