阅读说明：本技术 一种燃料电池系统 (Fuel cell system ) 是由 李萍萍 吴培华 李初福 周卫华 巴黎明 靳现林 姚金松 刘长磊 于 2019-02-27 设计创作，主要内容包括：本发明公开一种燃料电池系统,涉及燃料电池技术领域,为有效提高燃料气体的全程燃料利用率,提高发电效率而发明。燃料电池系统包括燃料电池组件；阳极换热器,阳极换热器包括第一端口、第二端口、第三端口和第四端口,第一端口与第二端口连通,第三端口与所述第四端口连通,第一端口用于通过燃料气体,第二端口与燃料电池组件的阳极进气口连通,第三端口与燃料电池的阳极出气口连通,第四端口分别通过第一分流管和第二分流管与第一端口连通；脱碳脱水装置,脱碳脱水装置的进口端与第二分流管连通,出口端与第一端口连通。本发明燃料电池系统用于提高电池工作性能。(The invention discloses a fuel cell system, relates to the technical field of fuel cells, and aims to effectively improve the whole-process fuel utilization rate of fuel gas and improve the power generation efficiency. The fuel cell system includes a fuel cell assembly; the anode heat exchanger comprises a first port, a second port, a third port and a fourth port, the first port is communicated with the second port, the third port is communicated with the fourth port, the first port is used for allowing fuel gas to pass through, the second port is communicated with an anode gas inlet of the fuel cell assembly, the third port is communicated with an anode gas outlet of the fuel cell, and the fourth port is communicated with the first port through a first shunt pipe and a second shunt pipe respectively; and the inlet end of the decarburization dehydration device is communicated with the second shunt pipe, and the outlet end of the decarburization dehydration device is communicated with the first port. The fuel cell system of the present invention is used to improve the cell operation performance.)

1. A fuel cell system, characterized by comprising:

a fuel cell assembly for generating electrical energy from a fuel gas and an oxygen-containing gas;

the anode heat exchanger comprises a first port, a second port, a third port and a fourth port, the first port is communicated with the second port, the third port is communicated with the fourth port, the first port is used for introducing the fuel gas, the second port is communicated with an anode gas inlet of the fuel cell assembly, the third port is communicated with an anode gas outlet of the fuel cell assembly, the fourth port is respectively communicated with a first shunt pipe and a second shunt pipe, and the other end of the first shunt pipe is communicated with the first port;

and the inlet end of the decarburization dehydration device is communicated with the other end of the second shunt pipe, and the outlet end of the decarburization dehydration device is communicated with the first port.

2. The fuel cell system according to claim 1, wherein a first flow controller is mounted on the first shunt tube, the first flow controller being configured to control a flow rate of the gas flowing into the first shunt tube from the fourth port, and a second flow controller is mounted on the second shunt tube, the second flow controller being configured to control a flow rate of the gas flowing into the second shunt tube from the fourth port.

3. The fuel cell system according to claim 2, further comprising:

a humidity measuring instrument installed at the first port of the anode heat exchanger and measuring a content of water in the fuel gas flowing into the first port;

the input end of the processor is connected with the humidity measuring instrument, the output end of the processor is connected with the first flow controller and the second flow controller respectively, the processor is used for calculating the actual water-carbon ratio of the fuel gas flowing into the first port, and correspondingly adjusting the flow of the gas in the first shunt pipe through controlling the first flow regulator and adjusting the flow of the gas in the second shunt pipe through controlling the second flow regulator according to the actual water-carbon ratio and the preset water-carbon ratio.

4. The fuel cell system according to claim 3, wherein when a volume ratio of hydrogen to carbon monoxide in the fuel gas is 1.5 to 2: 1 hour, the ratio of the flow of the gas in the first shunt pipe to the flow of the gas in the second shunt pipe is 0.9-4: 1.

5. the fuel cell system according to claim 1, wherein a cooler is installed at an inlet end of the decarburization dehydration unit.

6. The fuel cell system of claim 1, wherein the outlet end of the decarbonization and dehydration device is further communicated with a purge gas pipe.

7. The fuel cell system according to claim 6, wherein the flow rate of the gas in the purge gas pipe is 5% to 10% of the flow rate of the gas discharged from the outlet end of the decarburization dehydration engine.

8. The fuel cell system according to claim 1, wherein the operating pressure of the decarburization dehydration unit is 2Mpa to 3 Mpa.

9. The fuel cell system according to claim 1, wherein a first pressure-increasing device is installed at an outlet end of the decarburization dehydration unit.

10. The fuel cell system according to claim 1, further comprising:

the cathode heat exchanger comprises a fifth port, a sixth port, a seventh port and an eighth port, the fifth port is communicated with the sixth port, the seventh port is communicated with the eighth port, the fifth port is used for introducing the oxygen-containing gas, the sixth port is communicated with a cathode gas inlet of the fuel cell assembly, and the seventh port is communicated with a cathode gas outlet of the fuel cell assembly.

11. The fuel cell system according to claim 10, wherein a second pressure increasing device is installed at the fifth port of the cathode heat exchanger.

Technical Field

The invention relates to the technical field of fuel cells, in particular to a fuel cell system.

Background

Solid oxide fuel cells use relatively inexpensive hydrocarbons such as natural gas and coal-fired syngas as fuel gas to provide a source of hydrogen, and air as an oxygen source, with the hydrocarbons being reformed upstream of the fuel cell assembly.

The one-way fuel utilization rate (the one-way fuel utilization rate refers to the utilization rate of fuel gas which enters the cell from the anode gas inlet and is combusted and then is discharged from the anode gas outlet) of the existing solid oxide fuel cell generally does not exceed 85%, so that the tail gas discharged from the anode gas outlet of the cell contains part of unused fuel gas (the main components are CO and H)₂) In order to fully recover the heat value of the fuel gas, the tail gas circulation can be arranged to improve the overall fuel utilization rate of the fuel gas (the overall fuel utilization rate refers to the sum of the single pass and the circulation described above, and the utilization rate of the fuel gas), so that the chemical energy of the fuel gas can be converted into electric energy as much as possible.

Disclosure of Invention

Embodiments of the present invention provide a fuel cell system, which mainly aims to make full use of fuel exhaust gas of a fuel cell and avoid CO in the fuel exhaust gas₂The concentration of the combustible gas is diluted, the heat discharged by the tail gas of the fuel cell is fully utilized, the water-carbon ratio of the reaction is guaranteed, the whole-process fuel utilization rate of the fuel gas is effectively improved, and the power generation efficiency is improved.

In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:

an embodiment of the present invention provides a fuel cell system, including:

a fuel cell assembly for generating electrical energy from a fuel gas and an oxygen-containing gas;

the anode heat exchanger comprises a first port, a second port, a third port and a fourth port, the first port is communicated with the second port, the third port is communicated with the fourth port, the first port is used for introducing the fuel gas, the second port is communicated with an anode gas inlet of the fuel cell assembly, the third port is communicated with an anode gas outlet of the fuel cell, the fourth port is respectively communicated with a first shunt pipe and a second shunt pipe, and the other end of the first shunt pipe is communicated with the first port;

and the inlet end of the decarburization dehydration device is communicated with the other end of the second shunt pipe, and the outlet end of the decarburization dehydration device is communicated with the first port.

In the fuel cell system provided by the embodiment of the invention, because the anode heat exchanger is adopted, namely, the high-temperature fuel waste gas discharged from the anode gas outlet of the fuel cell assembly is subjected to heat exchange with the fuel gas to preheat the fuel gas, the energy of the high-temperature fuel waste gas is fully utilized, the power generation efficiency of the fuel cell assembly is ensured, the fuel cell system is energy-saving and environment-friendly, meanwhile, one end of the first shunt pipe is communicated with the fourth port of the anode heat exchanger, the other end of the first shunt pipe is communicated with the first port of the anode heat exchanger, one end of the second shunt pipe is communicated with the fourth port of the anode heat exchanger, the other end of the second shunt pipe is communicated with the inlet end of the decarburization dehydration device, and the outlet end of the decarburization dehydration device is communicated with the first port of the anode heat exchanger, thus, under the condition that the effective components in the fuel, and effectively ensures the water-carbon ratio of the fuel gas entering the fuel cell assembly.

Optionally, a first flow controller is installed on the first shunt tube, the first flow controller is used for controlling the flow of the gas flowing into the first shunt tube from the fourth port, a second flow controller is installed on the second shunt tube, and the second flow controller is used for controlling the flow of the gas flowing into the second shunt tube from the fourth port.

Optionally, the fuel cell system further includes:

a humidity measuring instrument installed at the first port of the anode heat exchanger and measuring a content of water in the fuel gas flowing into the first port;

the input end of the processor is connected with the humidity measuring instrument, the output end of the processor is connected with the first flow controller and the second flow controller respectively, the processor is used for calculating the actual water-carbon ratio of the fuel gas flowing into the first port, and correspondingly adjusting the flow of the gas in the first shunt pipe through controlling the first flow regulator and adjusting the flow of the gas in the second shunt pipe through controlling the second flow regulator according to the actual water-carbon ratio and the preset water-carbon ratio.

Optionally, when the volume ratio of hydrogen to carbon monoxide in the fuel gas is 1.5-2: 1 hour, the ratio of the flow of the gas in the first shunt pipe to the flow of the gas in the second shunt pipe is 0.9-4: 1.

optionally, a cooler is installed at an inlet end of the decarburization dehydration device.

Optionally, the outlet end of the decarburization dehydration device is also communicated with a purge gas pipe.

Further, the gas flow in the purge gas pipe accounts for 5-10% of the gas flow discharged from the outlet end of the decarburization dehydration device.

Optionally, the working pressure of the decarburization dehydration device is 2 Mpa-3 Mpa.

Optionally, a first pressure increasing device is installed at the outlet end of the decarburization dehydration device.

Optionally, the fuel cell system further includes:

the cathode heat exchanger comprises a fifth port, a sixth port, a seventh port and an eighth port, the fifth port is communicated with the sixth port, the seventh port is communicated with the eighth port, the fifth port is used for introducing the oxygen-containing gas, the sixth port is communicated with a cathode gas inlet of the fuel cell assembly, and the seventh port is communicated with a cathode gas outlet of the fuel cell assembly.

Further, a second pressure boosting device is installed at the fifth port of the cathode heat exchanger.

Drawings

Fig. 1 is a schematic structural diagram of a fuel cell system according to an embodiment of the present invention;

fig. 2 is a schematic block circuit diagram of a control device in a fuel cell system according to an embodiment of the present invention.

Detailed Description

A fuel cell system according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

Referring to fig. 1, an embodiment of the present invention provides a fuel cell system including: a fuel cell assembly 1, an anode heat exchanger 2 and a decarburization dehydration unit 3, wherein the fuel cell assembly 1 is used for generating electric energy by fuel gas and oxygen-containing gas; the anode heat exchanger 2 comprises a first port 01, a second port 02, a third port 03 and a fourth port 04, wherein the first port 01 is communicated with the second port 02, the third port 03 is communicated with the fourth port 04, the first port 01 is used for introducing fuel gas, the second port 02 is communicated with an anode gas inlet of the fuel cell assembly 1, the third port 03 is communicated with an anode gas outlet of the fuel cell assembly 1, the fourth port 04 is respectively communicated with a first shunt pipe 5 and a second shunt pipe 6, and the other end of the first shunt pipe 5 is communicated with the first port 01; the inlet end of the decarburization dehydration unit 3 is communicated with the other end of the second shunt pipe 6, and the outlet end of the decarburization dehydration unit 3 is communicated with the first port 01.

When the fuel cell system is used for generating electricity, oxygen-containing gas is introduced through a cathode gas inlet of the fuel cell component 1, meanwhile, fuel gas is introduced through the first port 01 of the anode heat exchanger 2, the fuel gas enters the fuel cell component 1 through the third port 03 and an anode gas inlet of the fuel cell component 1, and the introduced fuel gas and the oxygen-containing gas generate electrochemical reaction to convert chemical energy into electric energy. Along with the continuous introduction of the fuel gas and the oxygen-containing gas, high-temperature gas (the gas temperature is about 700-.

The high temperature gas discharged from the anode outlet typically contains water vapor (H) generated by the reaction₂O), carbon dioxide (CO)₂) And unreacted hydrogen (H)₂) And carbon monoxide (CO) in order to reuse unreacted hydrogen (H)₂) And carbon monoxide (CO), the present embodiment provides a fuel cell system including a circulation loop to circulate unreacted hydrogen (H)₂) And carbon monoxide (CO) are fully utilized, so that the whole fuel utilization rate and the power generation efficiency of the whole fuel gas are finally improved, meanwhile, the steam is also favorable for the steam reforming reaction inside the fuel cell assembly 1, and the phenomenon of coking in the fuel cell assembly 1 is also avoided.

The high-temperature gas discharged from the anode gas outlet is subjected to heat exchange with the low-temperature fuel gas by the anode heat exchanger 2, and then the gas (containing H) discharged from the fourth port 04₂O、CO₂、H₂CO, and the like, and the temperature is about 300 ℃), in order to avoid the dilution of the concentrations of carbon monoxide and hydrogen by water vapor and carbon dioxide with large contents, which affects the progress of the electrochemical reaction, and in order to ensure the water-carbon ratio of the fuel gas entering the fuel cell assembly 1, the circulation loop of the fuel cell system provided by the embodiment of the invention includes two circulation loops: referring to FIG. 1, a part of the gas flows into an anode heat exchanger 2 through a first shunt pipe 5 in a first circulation loop, and the rest of the gas flows into a second shunt pipe 6 in a second circulation loop, and then passes through a decarburization dehydration device 3 to oxidize water and dioxide in the gasThe carbon is removed and the removed gas flows into the anode heat exchanger 2, that is, the first path mixes the gas containing water and carbon dioxide with the fresh fuel gas, and the second path mixes the gas not containing water and carbon dioxide with the fresh fuel gas, so that the purpose of the design is as follows: on the premise of ensuring that the steam enters the fuel cell assembly 1 to carry out the reforming reaction, the water-carbon ratio of the fuel gas entering the fuel cell assembly 1 can be ensured, and the generating capacity and the generating efficiency of the fuel cell assembly 1 are further improved.

The following description will be made of a specific reaction process of the fuel cell system by taking synthesis gas generated by coal combustion as an example:

the main components of the synthesis gas generated by coal combustion comprise: CO, H₂Small amount of CH₄、CO₂And N₂Synthesis gas and H from the first partial flow pipe 5₂O、CO₂、H₂CO and H discharged from the decarbonization and dehydration unit 3₂Mixed with CO and discharged through the anode heat exchanger 2 to the anode outlet (including H)₂O、CO₂、H₂And CO) and enters the anode inlet of the fuel cell assembly 1 through the second port 02, and simultaneously, air enters the fuel cell assembly 1 through the cathode inlet of the fuel cell assembly 1, and oxygen in the air passes through the electrolyte and CO and H in the fuel gas₂、CH₄An electrochemical reaction occurs to generate electricity.

The effect of the fuel cell system provided by the embodiment of the invention is analyzed by experimental data by introducing synthesis gas to the anode of the fuel cell assembly 1 at a flow rate of 252L/Min, and simultaneously introducing air to the cathode of the fuel cell assembly 1 at a flow rate of 6347L/Min:

if all of the gas exiting the anode outlet of the fuel cell assembly 1 is passed through the first port 01 of the anode heat exchanger 2, the water to carbon ratio of the fuel gas entering the anode inlet of the fuel cell assembly 1 is 3.3, and CO and H are present₂The concentration of the gas is 5.1 percent and 9.2 percent respectively, the power generation efficiency of the electric pile is 58.6 percent, the whole-process fuel utilization rate of the synthesis gas is 95.0 percent, and the purge gas ratio is 10 percent;

if mixing fuelAll the gas discharged from the anode gas outlet of the cell assembly 1 is decarbonized and dehydrated by the decarbonization and dehydration device 3 and then passes through the first port 01 of the anode heat exchanger 2, so that the water-carbon ratio of the fuel gas entering the anode gas inlet of the fuel cell assembly 1 is 0.96, and the CO and the H are mixed₂The concentration of the catalyst is 32.2 percent and 58.1 percent respectively, the whole-process fuel utilization rate of the synthesis gas is 93.8 percent, and the electricity generation efficiency of the electric pile is 64.1 percent.

If 50% of the total gas discharged from the anode outlet of the fuel cell assembly 1 is decarbonized by the decarbonization and dehydration device 3 and then passes through the first port 01 of the anode heat exchanger 2, and the rest of the gas passes through the first port 01 of the anode heat exchanger 2, the water-carbon ratio of the fuel gas entering the anode inlet of the fuel cell assembly 1 is 2.1, and the CO and the H are₂The concentration of the catalyst is respectively 19.4 percent and 35.1 percent, the power generation efficiency of the galvanic pile is 62.6 percent, and the whole-process fuel utilization rate of the synthesis gas is 97.4 percent.

It is evident from the above experimental data that: when the embodiment of the invention is adopted to carry out electrochemical reaction on the synthesis gas and air, the water-carbon ratio of the fuel gas entering the anode air inlet of the fuel cell component 1 is higher than 2.0, so that the internal coking and carbon deposition of the cell can be effectively prevented, the whole-process fuel utilization rate of the synthesis gas is obviously higher than the other two conditions, and the power generation efficiency of the pile is ensured, therefore, the whole-process fuel utilization rate of the synthesis gas can be effectively improved by the fuel cell system.

In order to ensure that the water-carbon ratio of the fuel gas entering the anode gas inlet of the fuel cell assembly 1 is always higher than 2.0, when the volume ratio of hydrogen to carbon monoxide in the fuel gas is 1.5-2: 1, the ratio of the flow of the gas in the first shunt pipe 5 to the flow of the gas in the second shunt pipe 6 is 0.9-4: 1, if the ratio is more than 4, the content of water vapor in the fuel gas can be increased, when the content of the water vapor is higher, the concentration of carbon monoxide and hydrogen can be correspondingly reduced, the efficiency of electrochemical reaction is reduced, if the ratio is less than 0.9, the concentration of CO in the fuel gas can be increased, a series of carbon deposition and coking processes are caused, the performance of a galvanic pile is influenced, the attenuation of the galvanic pile is caused, and the system can be shut down when the ratio is serious. Preferably, when the volume ratio of hydrogen to carbon monoxide in the fuel gas is 1.6:1, the ratio of the flow rate of the gas in the first shunt pipe 5 to the flow rate of the gas in the second shunt pipe 6 is 1: 1.

when the gas of first shunt tube 5 flowed into the first port 01 of anode heat exchanger 2, in order to avoid gas calorific loss when 5 internal flows of first separator, guarantee thermal effective utilization is provided with insulation construction on the first shunt tube 5, can effectively utilize the energy of the gas in the first shunt tube 5 through insulation construction, and then improve whole fuel cell system's energy utilization. For example, the heat insulation structure may be a heat insulation layer, and the heat insulation layer is coated on the outer wall of the first shunt pipe 5; in another example, the first shunt tube 5 is sleeved in the outer tube, a vacuum cavity is formed between the outer tube and the first shunt tube 5, and the vacuum cavity forms a heat preservation structure; in addition, the heat insulating structure may have other structures.

In order to more accurately control the flow rate of the gas flowing into the first shunt pipe 5, referring to fig. 1, a first flow controller for controlling the flow rate of the gas flowing into the first shunt pipe 5 from the fourth port 24 is installed on the first shunt pipe 5.

In order to more accurately control the flow rate of the gas flowing into the second shunt pipe 6, referring to fig. 1, a second flow controller for controlling the flow rate of the gas flowing into the second shunt pipe 6 from the fourth port 24 is installed on the second shunt pipe 6.

It should be noted that: a total flow controller may be provided at the fourth port 04, so that an implementable solution includes: illustratively, a first flow rate controller is mounted on the first shunt pipe 5 and a total flow rate controller is provided at the fourth port 04; as another example, a second flow rate controller is installed on the second shunt pipe 6 and a total flow rate controller is provided at the fourth port 04; as another example, a first flow rate controller is mounted on the first shunt pipe 5, and a second flow rate controller is mounted on the second shunt pipe 6. The specific embodiment is not limited as long as the flow rate of the gas entering the first and second flow dividing pipes 5 and 6 can be accurately controlled.

The first flow rate controller and the second flow rate controller may be identical in structure or different in structure, and for convenience of implementation, the first flow rate controller and the second flow rate controller having the same structure are preferable.

In some embodiments, the first flow controller comprises a first control valve 7, a first flow meter 15 is mounted on the first shunt pipe 5, the first flow meter 15 is used for detecting the flow value of the gas in the first shunt pipe 5, and the flow rate of the gas flowing into the first shunt pipe 5 is controlled through the opening degree of the first control valve 7; the second flow controller includes a second control valve 8, a second flow meter 16 is mounted on the second shunt pipe 6, and the second flow meter 16 is used for detecting the flow value of the gas in the second shunt pipe 6 and controlling the flow of the gas flowing into the second shunt pipe 6 according to the opening degree of the second control valve 8.

The first control valve 7 and the second control valve 8 may be selected from a shut-off valve, a butterfly valve, and the like.

The first flowmeter 15 and the second flowmeter 16 may be selected from a high-temperature gas-resistant and corrosion-resistant flowmeter, such as a differential pressure flowmeter, an ultrasonic flowmeter, or the like, or from a mass flowmeter having high measurement accuracy.

Referring to fig. 1 and 2, the fuel cell system further includes: a humidity measuring instrument 13, the humidity measuring instrument 13 being installed at the first port 01 of the anode heat exchanger 2 and being used for measuring the content of water in the fuel gas flowing into the first port 01; and a processor 14, an input end of the processor 14 is connected to the humidity measuring instrument 13, an output end of the processor 14 is connected to the first flow controller (specifically, the first control valve 7) and the second flow controller (specifically, the second control valve 8), respectively, the processor 14 is configured to calculate an actual water-carbon ratio of the fuel gas flowing into the first port 01, and correspondingly adjust the flow rate of the gas in the first shunt pipe 5 by controlling the first flow regulator and the flow rate of the gas in the second shunt pipe 6 by controlling the second flow regulator according to the actual water-carbon ratio and the preset water-carbon ratio, and the input end of the processor 14 is also connected to the first flow meter 15 and the second flow meter 16. In specific implementation, the water-carbon ratio of the fuel gas flowing into the first port 01 can be accurately controlled through the cooperation of the processor 14, the first control valve 7 and the second control valve 8, so that the actual water-carbon ratio meets the preset water-carbon ratio.

The decarbonation and dehydration unit 3 has various configurations, for example, a hot potash absorption unit may be selected, i.e., a gas is washed by a solution containing chemically active substances to remove water and carbon dioxide; for another example, a pressure swing adsorption device may be selected to adsorb water vapor and carbon dioxide by using different gases having different adsorption capacities under different partial pressures; for another example, the gas may also be washed with MEDA (methyldiethanolamine) to remove water and carbon dioxide by a solution containing a chemically active substance. The specific structure of the decarburizing and dehydrating apparatus 3 is not limited, and any structure of the decarburizing and dehydrating apparatus 3 is within the scope of the present invention.

In order to ensure the decarburizing and dehydrating efficiency of the decarburizing and dehydrating device 3, the working pressure of the decarburizing and dehydrating device 3 is 2 MPa-3 MPa.

In order to ensure that the gas discharged from the anode gas outlet of the fuel cell module 1 can smoothly enter the decarburization dehydration unit 3 without a supercharging device, the working pressure of the fuel cell module 1 is also 2 Mpa-3 Mpa, so that the structure can be simplified, and meanwhile, when the fuel cell module 1 works under 2 Mpa-3 Mpa, the power generation voltage and the power generation efficiency can be effectively ensured.

In general, the operating temperature of the decarburizing and dehydrating apparatus 3 is 30 to 60 ℃, but the temperature of the gas discharged from the fourth port 24 of the anode heat exchanger 2 is about 300 ℃, and a cooler 9 is installed at the inlet end of the decarburizing and dehydrating apparatus 3 in order to ensure the operating performance of the decarburizing and dehydrating apparatus 3. That is, the gas flowing out from the fourth port 04 of the anode heat exchanger 2 enters the cooler 9 through the second branch pipe 6, and the gas is cooled by the cooler 9 so that the temperature of the gas entering the decarburization dehydration unit 3 satisfies the operating temperature of the decarburization dehydration unit 3.

In some embodiments, a cooling structure may be provided on the second flow dividing pipe 6, and the gas flowing through the second flow dividing pipe 6 is cooled by the cooling structure, for example, the second flow dividing pipe 6 is sleeved in an outer cylinder, and a cooling medium is filled between the outer cylinder and the second flow dividing pipe 6, and the cooling medium forms the cooling structure.

When the gas is discharged from the outlet end of the decarburization dehydration unit 3, the pressure of the gas is small, and in order to increase the flow pressure of the gas discharged from the outlet end of the decarburization dehydration unit 3, referring to fig. 1, a first supercharging device 10 is installed at the outlet end of the decarburization dehydration unit 3, the inlet end of the first supercharging device 10 communicates with the outlet end of the decarburization dehydration unit 3, and the outlet end of the first supercharging device 10 communicates with the first port 01 of the anode heat exchanger 2. The first pressure boosting device 10 may be a booster pump, a blower, or other pressure boosting device.

In order to prevent the inert gas from accumulating in the whole fuel cell system and affecting the electrochemical reaction efficiency, the inert gas, such as nitrogen or argon, is mixed with the gas discharged from the anode outlet, referring to fig. 1, the outlet of the decarbonization and dehydration unit 3 is further communicated with a purge gas pipe 12, and a small amount of inert gas in the gas is discharged through the purge gas pipe 12, thereby ensuring the reaction efficiency and the power generation amount.

The fuel cell system further includes: and the gas recovery device is communicated with the decarburization dehydration device 3 and is used for recovering the carbon dioxide and the water removed by the decarburization dehydration device 3. And collecting the carbon dioxide and the water through a gas recovery device for other chemical devices.

Referring to fig. 1, the fuel cell system further includes: and the cathode heat exchanger 4 comprises a fifth port 05, a sixth port 06, a seventh port 07 and an eighth port 08, the fifth port 05 is communicated with the sixth port 06, the seventh port 07 is communicated with the eighth port 08, the fifth port 05 is used for passing oxygen-containing gas, the sixth port 06 is communicated with a cathode gas inlet of the fuel cell assembly 1, and the seventh port 07 is communicated with a cathode gas outlet of the fuel cell assembly 1.

During specific power generation of the fuel cell system, high-temperature gas (the gas temperature is 700-800 ℃) can be discharged from a cathode gas outlet along with continuous feeding of fuel gas and oxygen-containing gas, and the high-temperature gas exchanges heat with the fed normal-temperature oxygen-containing gas in the cathode heat exchanger 4 to preheat the oxygen-containing gas, so that the temperature of the oxygen-containing gas is raised to be higher than 400 ℃. Through the arrangement of the cathode heat exchanger 4, the heat of the high-temperature gas exhausted from the cathode gas outlet is effectively utilized, so that a special heating device is not required, and the energy consumption of the whole fuel cell system is reduced.

In order to increase the flow pressure of the oxygen-containing gas, referring to fig. 1, a second pressure increasing device 11 is installed at the fifth port 05 of the cathode heat exchanger 4, an inlet end of the second pressure increasing device 11 is used for introducing the oxygen-containing gas, and an outlet end of the second pressure increasing device 11 is communicated with the fifth port 05 of the cathode heat exchanger 4. The second pressure increasing means 11 may be a booster pump, a blower or other pressure increasing means.

The fuel cell system provided by the embodiment of the invention is adopted to carry out simulation experiment, wherein the fuel gas is synthesis gas obtained by one-stage water gas change reaction, the oxygen-containing gas is air, and the synthesis gas comprises: h₂CO, small amount of N₂And CO₂And a hydrogen to carbon ratio of about 1.6:1, the set operating parameters include:

cell per pass conversion	65％
		Gas flow ratio in the first shunt pipe	50％
CO of decarbonization dehydration device2Removal rate	100％
		H of decarburization dehydration facility20 removal rate	100％
Purge gas ratio	10％

It should be noted that: in practiceIn-process CO₂And H₂The O can not be completely removed, and CO can be removed in the low-temperature methanol washing process₂And H₂O is reduced to ppm and ppb level, such trace amount of CO₂Has little influence on the process calculation, so for the convenience of the simulation calculation, CO is used₂And H₂The removal rate of O was set to 100%.

Simulation calculation is carried out by utilizing Aspen Plus software, and the simulation result is as follows:

water to carbon ratio of anode inlet	2.1
		N of anode gas inlet2Content (wt.)	8.3％
Power generation efficiency of battery	62.6％
		Net electrical efficiency of the system	60.2％

From the simulation results, it can be found that:

1. when the gas flow in the first shunt pipe accounts for 50%, the water-carbon ratio of the fuel gas can reach 2.1, coking is effectively prevented, and the water-carbon ratio can be conveniently and accurately adjusted by adjusting the gas ratio in the first shunt pipe.

2. Under the condition of setting 10% purge gas, N can be well prevented₂Is accumulated so as to make N in the fuel gas of the anode gas inlet₂The content is only 8.3%, and the condition of large-scale accumulation and dilution of effective gas does not occur.

3. The direct-current power generation efficiency of the battery can reach 62.6 percent, and the net power generation efficiency of the system is still 60.2 percent after the power consumption of power equipment such as the decarburization dehydration device 3, the supercharging device and the like is deducted.

The following comparison table is a comparison table of simulation experiment results of four fuel cell systems, wherein the first fuel cell system does not include anode tail gas circulation and anode tail gas decarburization dehydration treatment, the second fuel cell system does not include anode tail gas circulation and includes anode tail gas decarburization dehydration treatment recycling, the third fuel cell system includes anode tail gas circulation and does not include anode tail gas decarburization dehydration treatment, and the fourth fuel cell system provided by the embodiment of the present invention generates power under the same reaction conditions, and the reaction conditions include: composition of fuel gas, single pass fuel utilization of fuel gas, flow rate of fuel gas, stack operating pressure, stack operating temperature, purge gas ratio:

the fuel gas used in the above four fuel cell systems was syngas, in which the ratio of the main components H2 and CO in syngas was 1.6: 1.

It is evident from the above comparative table that: under the condition that the water-carbon ratio meets the requirement, the net electric efficiency of the fuel cell system provided by the embodiment of the invention has obvious advantages compared with the other three fuel cell systems. Although the second fuel cell system has high electrical efficiency, the water-carbon ratio is only 0.96, which causes carbon deposition of the stack and further affects the stack performance.

In the description herein, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.