Temperature control system of solid oxide fuel cell power generation device

Abstract

The invention provides a temperature control system of a solid oxide fuel cell power generation device. The temperature control system comprises a solid oxide electric pile, a hot box, a preheater, a heat exchanger, a fan, a combustion-supporting air flow meter, a combustion-supporting air electric control valve, a cathode air flow meter and a cathode air electric control valve, the method has the beneficial effects that in the cold start stage, high-temperature combustion tail gas is input into the hot box through the preheater, the combustion tail gas surrounds the periphery of the solid oxide galvanic pile to heat the solid oxide galvanic pile, and the heating rate of the galvanic pile can be controlled; in a power generation stage, if the temperature of the electric pile is lower than a set value, the preheater can be started again, and high-temperature combustion tail gas is input into the hot box, so that the temperature of the electric pile rises to a set working temperature; if the temperature of the galvanic pile is higher than the set value, fuel input into the preheater can be stopped, and room-temperature air is input into the hot box only through the preheater, so that the temperature of the galvanic pile is reduced to the set working temperature, and the galvanic pile is always at the optimal working temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid oxide fuel cells, and particularly relates to a temperature control system for a solid oxide fuel cell power generation device. Background Art

[0002] At present, solid oxide fuel cells have become a key research project in the field of hydrogen energy applications. Due to the low requirement for hydrogen purity and high power generation efficiency, they are receiving increasing attention in the hydrogen energy field. However, since the operating temperature of solid oxide fuel cells is as high as about 700 degrees Celsius, there are many temperature control problems. For example, the temperature rise of the stack is slow during the cold start preheating stage, and it is difficult to control the stack temperature too high or too low during the normal power generation stage. Summary of the Invention

[0003] Object of the Invention: The technical problem to be solved by the present invention is to provide a temperature control system for a solid oxide fuel cell power generation device, which can control the temperature rise rate of the stack within a set range during the cold start preheating stage and control the stack temperature within the optimal temperature range during the normal power generation stage.

[0004] A temperature control system for a solid oxide fuel cell power generation device, characterized in that it includes a solid oxide stack, a hot box, a preheater, a fan, a combustion air flowmeter, a combustion air electronic control valve, a cathode air flowmeter, and a cathode air electronic control valve; The solid oxide stack is arranged in the hot box. The input and output pipelines of the anode flow channel of the stack penetrate to the outside of the hot box respectively. The inlet pipeline of the cathode flow channel of the stack penetrates to the outside of the hot box, and the outlet of the cathode flow channel of the stack is arranged inside the hot box. A hot box preheating gas inlet and a hot box waste gas outlet are provided on the hot box housing; A fuel inlet, a combustion air inlet, a burner, an igniter, and a preheater tail gas outlet are provided on the preheater. The outlet of the fan is connected to the inlet of the combustion air flowmeter, the outlet of the combustion air flowmeter is connected to the inlet of the combustion air electronic control valve, the outlet of the combustion air electronic control valve is connected to the combustion air inlet of the preheater, and the preheater tail gas outlet is connected to the hot box preheating gas inlet. The outlet of the fan is connected to the inlet of the cathode air flowmeter, the outlet of the cathode air flowmeter is connected to the inlet of the cathode air electronic control valve, and the outlet of the cathode air electronic control valve is connected to the inlet of the cathode flow channel of the stack; Further, it further includes a heat exchanger. The cold side flow channel of the heat exchanger is connected in series between the inlet of the cathode flow channel of the stack and the cathode air electronic control valve. The hot box waste gas outlet is connected to the inlet of the hot side flow channel of the heat exchanger.

[0005] The beneficial effects of the present invention are as follows: during the cold start phase, high-temperature combustion exhaust gas is input into the hot box through the preheater. The combustion exhaust gas surrounds the solid oxide fuel cell stack to heat it up. The flow rates of the fuel and combustion-supporting air input into the preheater can be controlled, thereby controlling the heating rate of the fuel cell stack. After the fuel cell stack is heated up to the set operating temperature, hydrogen is input into the anode flow channel of the fuel cell stack, and air is input into the cathode flow channel of the fuel cell stack. Then the fuel cell stack can enter the normal power generation phase. During the power generation phase, if the temperature of the fuel cell stack is lower than the set value, the preheater can be turned on again to input high-temperature combustion exhaust gas into the hot box to raise the temperature of the fuel cell stack to the set operating temperature. If the temperature of the fuel cell stack is higher than the set value, the fuel input into the preheater can be stopped, and only room-temperature air is input into the hot box through the preheater to lower the temperature of the fuel cell stack to the set operating temperature, so that the fuel cell stack is always at the optimal operating temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a schematic diagram of an embodiment of the present invention; Reference numerals: 10 - solid oxide fuel cell stack, 11 - anode flow channel of the fuel cell stack, 12 - cathode flow channel of the fuel cell stack, 12a - inlet of the cathode flow channel of the fuel cell stack, 12b - outlet of the cathode flow channel of the fuel cell stack, 20 - hot box, 20a - inlet of the preheating gas of the hot box, 20b - outlet of the waste gas of the hot box, 30 - preheater, 31 - fuel inlet, 32 - combustion-supporting air inlet, 33 - burner, 34 - igniter, 35 - outlet of the exhaust gas of the preheater, 40 - heat exchanger, 41 - hot side flow channel of the heat exchanger, 42 - cold side flow channel of the heat exchanger, 50 - fan, 51 - combustion-supporting air flowmeter, 52 - combustion-supporting air electric control valve, 53 - cathode air flowmeter, 54 - cathode air electric control valve. EMBODIMENTS

[0007] It should be noted that in the description and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that technicians may use different terms to refer to the same component. The description and claims of this specification do not use the difference in terms as a way to distinguish components, but use the difference in functions of components as the criterion for distinction. For example, the term "comprising" or "including" mentioned throughout the description and claims is an open-ended term, so it should be interpreted as "including but not limited to". The "fuel cell stack" in this specification and claims is an abbreviation of "fuel cell".

[0008] For the convenience of understanding the embodiments of the present invention, the following will be further explained with reference to the drawings: Figure 1 is a preferred embodiment of the present invention, a temperature control system for a solid oxide fuel cell power generation device, It includes a solid oxide stack 10, a hot box 20, a preheater 30, a heat exchanger 40, a blower 50, a combustion air flowmeter 51, a combustion air electronic control valve 52, a cathode air flowmeter 53, and a cathode air electronic control valve 54; The solid oxide stack 10 is arranged inside the hot box 20. The input and output pipelines of the anode flow channel 11 of the stack penetrate to the outside of the hot box 20 respectively. The pipeline of the cathode flow channel inlet 12a of the stack penetrates to the outside of the hot box, and the cathode flow channel outlet 12b of the stack is arranged inside the hot box 20. A hot box preheating gas inlet 20a and a hot box exhaust gas outlet 20b are arranged on the shell of the hot box 20; A fuel inlet 31, a combustion air inlet 32, a burner 33, an igniter 34, and a preheater tail gas outlet 35 are arranged on the preheater 30. The outlet of the blower 50 is connected to the inlet of the combustion air flowmeter 51. The outlet of the combustion air flowmeter 51 is connected to the inlet of the combustion air electronic control valve 52. The outlet of the combustion air electronic control valve 52 is connected to the combustion air inlet 32. The preheater tail gas outlet 35 is connected to the hot box preheating gas inlet 20a. The outlet of the blower 50 is connected to the inlet of the cathode air flowmeter 53. The outlet of the cathode air flowmeter 53 is connected to the inlet of the cathode air electronic control valve 54. The outlet of the cathode air electronic control valve 54 is connected to the inlet of the cold side flow channel 42 of the heat exchanger. The outlet of the cold side flow channel 42 of the heat exchanger is connected to the cathode flow channel inlet 12a of the stack. The hot box exhaust gas outlet 20b is connected to the inlet of the hot side flow channel 41 of the heat exchanger.

[0009] The specific working process is as follows: Cold start stage: Start the blower 50, open the combustion air electronic control valve 52, input fuel from the fuel inlet 31, and turn on the igniter 34. Then the combustion air and the fuel are mixed and burned in the burner 33. The high-temperature combustion tail gas enters the hot box 20 from the preheater tail gas outlet 35 through the hot box preheating gas inlet 20a. The high-temperature combustion tail gas surrounds the outer wall of the solid oxide stack 10 to heat it up. The waste gas that has been cooled after absorbing heat by the solid oxide stack 10 is discharged from the hot box exhaust gas outlet 20b and is discharged into the air after passing through the hot side flow channel 41 of the heat exchanger. During the start-up heating process, the opening of the combustion air electronic control valve 52 can be adjusted according to the flow feedback value of the combustion air flowmeter 51 to make the combustion air flow within the set value range; Power generation stage: When the temperature of the solid oxide stack 10 rises to the set working temperature, fuel input from the fuel inlet 31 into the preheater 30 can be stopped, and then the combustion air electronic control valve 52 is closed to stop the input of combustion air. Then, hydrogen is input into the anode flow channel 11 of the stack. The blower 50 is turned on, and the cathode air electronic control valve 54 is opened. According to the flow feedback value of the cathode air flowmeter 53, the opening of the cathode air electronic control valve 54 is adjusted to make the cathode air flow within the set value range. At this time, the system enters the normal power generation stage; During the power generation process, when the electrical load of the user decreases, the power generation of the solid oxide stack 10 decreases, and its associated heat also decreases, which will cause the temperature of the solid oxide stack 10 to drop. When the temperature of the solid oxide stack 10 is lower than its allowable operating temperature, normal power generation cannot be carried out. In order to keep the temperature of the solid oxide stack 10 stable within the normal operating temperature range, the preheater 30 can be turned on again at this time to heat the solid oxide stack 10 so that its temperature rises and is maintained within the normal operating temperature range. During the power generation process, when the electrical load of the user increases, the power generation of the solid oxide stack 10 increases, and its associated heat also increases, which will cause the temperature of the solid oxide stack 10 to rise. If the temperature of the solid oxide stack 10 is higher than its allowable operating temperature, it will cause damage to the solid oxide stack 10. In order to keep the temperature of the solid oxide stack 10 stable within the normal operating temperature range, only the combustion air electronic control valve 52 can be opened at this time, but no fuel is input into the preheater 30. Then, the room temperature air flows through the preheater 30 and enters the hot box 20 to cool the solid oxide stack 10 so that its temperature drops and is maintained within the normal operating temperature range. The function of the heat exchanger 40 is to recover the heat in the exhaust gas discharged from the hot box exhaust gas outlet 20b, so that the cathode air flowing through the cold side flow channel 42 of the heat exchanger is heated and exchanges heat and then enters the cathode flow channel 12 of the stack. At the same time, the exhaust gas flowing through the hot side flow channel 41 of the heat exchanger is cooled and then discharged, reducing the heat loss of the system and improving the efficiency of the whole machine.

[0010] The embodiments of the present invention have been described above, but the present invention is not limited to the above specific embodiments and application fields. The above specific embodiments are merely illustrative and guiding, rather than restrictive. Those of ordinary skill in the art, under the inspiration of this specification and without departing from the scope protected by the claims of the present invention, can also make many forms, and these all belong to the scope of protection of the present invention.

Claims

1. A temperature control system for a solid oxide fuel cell power generation device, characterized in that: It includes a solid oxide stack (10), a hot box (20), a preheater (30), a blower (50), a combustion-supporting air flowmeter (51), a combustion-supporting air electrically controlled valve (52), a cathode air flowmeter (53), and a cathode air electrically controlled valve (54); the solid oxide stack (10) is arranged inside the hot box (20), the input and output pipelines of the anode flow channel (11) of the stack penetrate to the outside of the hot box (20) respectively, the pipeline of the cathode flow channel inlet (12a) of the stack penetrates to the outside of the hot box (20), and the cathode flow channel outlet (12b) of the stack is arranged inside the hot box (20). On the shell of the hot box (20), there are a hot box preheating gas inlet (20a) and a hot box waste gas outlet (20b); on the preheater (30), there are a fuel inlet (31), a combustion-supporting air inlet (32), a burner (33), an igniter (34), and a preheater tail gas outlet (35); the outlet of the blower (50) is connected to the inlet of the combustion-supporting air flowmeter (51), the outlet of the combustion-supporting air flowmeter (51) is connected to the inlet of the combustion-supporting air electrically controlled valve (52), the outlet of the combustion-supporting air electrically controlled valve (52) is connected to the combustion-supporting air inlet (32) of the preheater (30), and the preheater tail gas outlet (35) is connected to the hot box preheating gas inlet (20a); the outlet of the blower (50) is connected to the inlet of the cathode air flowmeter (53), the outlet of the cathode air flowmeter (53) is connected to the inlet of the cathode air electrically controlled valve (54), and the outlet of the cathode air electrically controlled valve (54) is connected to the cathode flow channel inlet (12a) of the stack.

2. The temperature control system of a solid oxide fuel cell power generation device according to claim 1, characterized in that: It further includes a heat exchanger (40), the cold side flow channel (42) of the heat exchanger is connected in series between the cathode flow channel inlet (12a) of the stack and the cathode air electrically controlled valve (54); the hot box waste gas outlet (20b) is connected to the inlet of the hot side flow channel (41) of the heat exchanger.

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