A SOFC power generation system

Abstract

The present invention discloses a SOFC power generation system, which reacts fuel gas and air to generate electricity, and includes a preheating mechanism and a SOFC module. The SOFC module has a cavity in which a number of independent power generation chambers are installed, and the preheating mechanism is communicated with the cavity of the SOFC module. The preheating mechanism and the SOFC module are simultaneously communicated through an external pipeline for gas supply. The preheating mechanism has a combustion chamber and a blower. Fuel gas and oxygen are introduced into the combustion chamber for combustion and heat generation, and the blower blows air out of the combustion chamber and injects hot air into the cavity of the SOFC module for preheating.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and particularly relates to a SOFC power generation system. Background Art

[0002] A solid oxide fuel cell (SOFC) belongs to the third generation of fuel cells and is a fully solid-state chemical power generation device that directly and efficiently converts the chemical energy stored in fuels and oxidants into electrical energy at medium and high temperatures in an environmentally friendly manner. It has the highest theoretical energy density among several fuel cells and is generally considered to be a fuel cell that will be widely popularized and applied in the future, just like the proton exchange membrane fuel cell (PEMFC).

[0003] A general SOFC power generation system includes a fuel processing unit, a fuel cell power generation unit, and an energy recovery unit. Figure 1 It is a power generation system that uses natural gas as fuel and operates at atmospheric pressure. Air is compressed by a compressor, preheated in a preheater after overcoming the system resistance, and then introduced into the cathode of the cell. After being compressed by a compressor, natural gas overcomes the system resistance and enters a mixer, where it is mixed with superheated steam generated in a steam generator. The ratio of steam to fuel is [specific ratio]. The mixed fuel gas enters a heater to increase its temperature and then is introduced into the anode of the fuel cell. The anode and cathode gases undergo an electrochemical reaction in the cell. While the cell generates electrical energy, the heat generated by the electrochemical reaction heats the anode and cathode gases that have not reacted completely. The unreacted gas at the anode and the remaining oxidant at the cathode are introduced into a combustor for combustion. The high-temperature gas generated by combustion is used not only to preheat the fuel and air but also to provide the heat required by the steam generator. The combustion products after passing through the steam generator still have useful thermal energy, which can be further utilized by providing hot water or heating through a waste heat recovery device.

[0004] However, due to the slow start-up of the steam generator itself and the long time required to heat its temperature to the reaction temperature. And most SOFC power generation systems themselves use fuel gas for reaction power generation, and the thermal energy generated by subsequent reactions can preheat the gas or maintain the temperature in the reactor. At the same time, the heat can also be left over to heat other equipment. At this time, the steam preheater does not need to work. Therefore, the existing steam preheating method has low efficiency and does not meet the start-up and operation of equipment in some low-temperature environments. Summary of the Invention

[0005] To solve the problems existing in the prior art, the present invention provides a SOFC power generation system. The preheating structure directly heated by fuel gas combustion can quickly heat the SOFC module under extreme environmental conditions, so that the temperatures of several power generation chambers inside it can quickly rise to appropriate temperatures, thereby improving efficiency.

[0006] The technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention discloses a SOFC power generation system that reacts by introducing fuel gas and air for power generation, including a preheating mechanism and a SOFC module. The SOFC module has a cavity with several independent power generation chambers installed, and the preheating mechanism is communicated with the cavity of the SOFC module;

[0008] The preheating mechanism and the SOFC module are simultaneously communicated through an external pipeline for gas supply. The preheating mechanism has a combustion chamber and a blower. Fuel gas and oxygen are introduced into the combustion chamber for combustion and heat generation, and the blower blows air out of the combustion chamber and injects hot air into the cavity of the SOFC module for preheating;

[0009] A temperature sensor is provided in the power generation chamber. When the temperature in the power generation chamber is higher than the set first threshold, fuel gas and air are introduced through an external pipeline for reaction;

[0010] When the temperature in more than half of the power generation chambers rises to the second threshold and remains above the second threshold within the set time, the combustion chamber of the preheating mechanism is closed;

[0011] When the temperature in more than half of the power generation chambers rises to the third threshold and remains above the third threshold within the set time, the blower is turned on to inject air into the cavity of the SOFC module, and the hot air in the cavity of the SOFC module is introduced into an externally provided gas turbine or LOHC stack.

[0012] Combined with the first aspect, the present invention provides a first implementation manner of the first aspect. The SOFC module includes an electric stack shell and heat insulation tiles covering the outside of the electric stack shell;

[0013] The electric stack shell is a through-type shell structure with two parallel openings. A slide rail for slidably installing several power generation chambers is provided inside the electric stack shell.

[0014] Combined with the first implementation manner of the first aspect, the present invention provides a second implementation manner of the first aspect. Several convex strips are provided on the inner wall of the electric stack shell, and the ends of the convex strips abut against the outer surface of the power generation chamber entering the electric stack shell from all around.

[0015] Combined with the first aspect or the first to second implementation manners of the first aspect, the present invention provides a third implementation manner of the first aspect. The power generation chamber includes two outer shells that are buckled together. The outer shells are connected and fixed by bolts, and a sealing groove structure and high-temperature resistant caulking are provided at their joints.

[0016] Combined with the third implementation manner of the first aspect, the present invention provides a fourth implementation manner of the first aspect. The inner wall of the outer shell of the power generation chamber has a sunken groove, and a ceramic hollowed-out part is provided in the sunken groove;

[0017] The ceramic hollow part has a honeycomb structure, and the fuel gas or air entering the power generation chamber enters the ceramic hollow part and diffuses.

[0018] In combination with the fourth embodiment of the first aspect, the present invention provides a fifth embodiment of the first aspect, wherein the outer shell of the power generation chamber is an integrated structure made of silicon nitride ceramic material, a diffusion portion is formed by thickening the inner wall of the outer shell, and a number of holes that are interconnected and pass through the entire diffusion portion are hollowed out in the diffusion portion to form a ceramic hollow part.

[0019] In combination with the fifth embodiment of the first aspect, the present invention provides a sixth embodiment of the first aspect, wherein the outer wall of the power generation chamber is provided with an air intake pipe and an exhaust pipe that protrude outward and are integrally formed with the outer shell, which are connected to the air intake pipe and the exhaust pipe through a pipeline arranged in the fuel cell shell, and the connection is sealed with a high-temperature resistant plugging material.

[0020] In combination with the sixth embodiment of the first aspect, the present invention provides a seventh embodiment of the first aspect, wherein both the air intake pipe and the exhaust pipe are connected to the ceramic hollow member;

[0021] When the two shells are buckled together, a plate-shaped electrolyte is provided in the middle of the power generation chamber at the buckling position of the shells, and electrode plates are provided on both sides of the electrolyte and are attached to the surface of the ceramic hollow part.

[0022] It should be noted that existing SOFC stack structures all have several single cells. Each cell has a relatively low voltage, so several cells need to be connected in series to generate electricity simultaneously, forming the power generation compartments described in the present invention. Each power generation compartment is secured with a loose, porous ceramic interconnect structure or one with several directional channels as a heat-resistant structure. However, this heat-resistant structure conducts heat only internally, creating a stable temperature environment within a single area, which is conducive to the corresponding gas reactions at the corresponding electrodes.

[0023] In this application, a ceramic hollow part serving as a connector is integrally formed with the outer shell of the power generation chamber and is made of silicon nitride, a material with high thermal conductivity and high temperature resistance. This allows the heat inside the shell to be quickly transferred to the entire outer shell surface, while also allowing the heat outside the shell to be quickly transferred to the inside, which is beneficial for the external preheating mechanism to heat up quickly, and is also beneficial for the later transfer of excess reaction heat to the outside, and the hot air is transferred to the corresponding structure through a blower.

[0024] The beneficial effects of the present invention are:

[0025] (1) Through the integrated SOFC module structure, the present invention can form a heat conduction air duct inside the stack shell, and preheat it with the hot air generated by the combustion of fuel gas. Compared with the method of preheating the gas in each intake pipe after mixing through a steam preheating device, it has higher heating efficiency, faster temperature rise, simpler structure, and does not need to deal with the problem of pipe blockage caused by scale generated by heating, and the maintenance cost is lower;

[0026] (2) Through the multi-temperature threshold control method provided by the present invention, heat conduction control can be carried out according to the temperature conditions of each power generation compartment. It can not only automatically adjust the working time of the preheater, reduce manual control steps, but also cooperate with other devices to utilize the waste heat, thereby increasing the efficiency;

[0027] (3) Through the integrated power generation compartment housing structure and ceramic hollow part structure provided by the present invention, due to the material characteristics of its high thermal conductivity, rapid and sufficient heat exchange can be carried out between the outside and inside of the power generation compartment, thus forming a suitable preheating method for this integral type, and can also quickly discharge excessive internal heat to the outside for corresponding disposal during normal operation;

[0028] (4) By transferring different thermal energies of the power generation compartment to different devices, the present invention can achieve better operating effects. The relatively low-temperature hot air transferred from the housing is transferred to the LOHC system by a blower to maintain the ambient temperature when the organic liquid releases hydrogen, and at the same time, the internal exhaust gas with higher temperature and pressure is transported to a gas turbine for power generation, thus forming a comprehensive waste heat utilization system with better integration and utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a plan view of preheating the SOFC module by a hydrogen burner in an embodiment of the present invention;

[0030] Figure 2 is an axonometric view of preheating the SOFC module by a hydrogen burner in an embodiment of the present invention;

[0031] Figure 3 is a side view of the SOFC module after removing the external heat insulation tiles in an embodiment of the present invention;

[0032] Figure 4 is an axonometric view of the SOFC module after removing the external heat insulation tiles in an embodiment of the present invention;

[0033] Figure 5 is a front view of a single power generation compartment in an embodiment of the present invention;

[0034] Figure 6 is a side view of a single power generation compartment in an embodiment of the present invention;

[0035] Figure 7 It is an isometric view of a single power generation chamber in an embodiment of the present invention;

[0036] Figure 8 It is an isometric schematic diagram of the internal components after the outer shell of a single power generation chamber in an embodiment of the present invention is disassembled.

[0037] In the figure: 1 - stack shell, 2 - heat insulation tile, 3 - power generation chamber, 4 - intake pipe, 5 - exhaust pipe, 6 - ceramic hollow part, 7 - electrode plate, 8 - electrolyte;

[0038] A - hydrogen burner, B - SOFC module. Detailed implementation manners

[0039] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments.

[0040] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Usually, the components of the embodiments of the present application described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents the selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0042] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0043] In the description of the present application, it should be noted that if terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of this application is usually placed when in use. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. In addition, in the description of the present application, if terms such as "first", "second", etc. are used only for distinguishing descriptions, they cannot be understood as indicating or implying relative importance.

[0044] In addition, in the description of the present application, terms such as "horizontal" and "vertical" do not mean that the components are required to be absolutely horizontal or hanging vertically, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0045] In the description of the present application, it should also be noted that unless otherwise clearly specified and limited, terms such as "set", "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0046] Embodiment 1:

[0047] This embodiment discloses a SOFC power generation system that reacts by introducing fuel gas and air for power generation.

[0048] Among them, the fuel gas in this embodiment is hydrogen, and the system includes a preheating mechanism and a SOFC module B.

[0049] Among them, the preheating mechanism is a hydrogen burner A, and the SOFC module B has a cavity in which a number of independent power generation chambers 3 are installed. The preheating mechanism is communicated with the cavity of the SOFC module B; the preheating mechanism and the SOFC module B are simultaneously communicated through an external pipeline for gas supply. The preheating mechanism has a combustion chamber and a blower. Fuel gas and oxygen are introduced into the combustion chamber for combustion and heat generation, and the blower blows air out of the combustion chamber and injects hot air into the cavity of the SOFC module B for preheating.

[0050] Among them, the SOFC module B is a type of polymer fuel cell. The most efficient one is the solid oxide fuel cell (SOFC), also known as the ceramic fuel cell, and its efficiency can reach 65% - 80%. However, the operating temperature is relatively high, about 650 - 1000 °C, so the reaction activity is extremely high.

[0051] SOFC is a solid oxide fuel cell that efficiently converts the chemical energy of various fuel gases into electrical energy at medium to high temperatures. From the structure of SOFC, it consists of an electrolyte 8, an anode / cathode, and a connector to form a single cell, and multiple single cells form a stack. SOFC operates at a high temperature, generally above 650 degrees to achieve full load operation. It should be noted that at the entire system level, a fuel supply system, a gas supply system (heater, compressor), a control system (voltage regulator, inverter), and other components such as heat exchangers are also required to ensure the stable operation of the entire system. This invention only provides the core components for SOFC power generation, and the other corresponding subsystems are external structures. SOFC operates at a relatively high temperature, allowing for a larger electrode temperature rise compared to PEMFC, and its water and heat management are relatively simple.

[0052] Among them, a temperature sensor is provided in the power generation chamber 3. When the temperature in the power generation chamber 3 is higher than the set first threshold, fuel gas and air are introduced through an external pipeline for reaction.

[0053] When the temperature in more than half of the power generation chamber 3 rises to the second threshold and remains above the second threshold within the set time, the combustion chamber of the preheating mechanism is closed;

[0054] When the temperature in more than half of the power generation chamber 3 rises to the third threshold and remains above the third threshold within the set time, a blower is turned on to inject air into the cavity of the SOFC module, and the hot air passing through the cavity of the SOFC module is introduced into a gas turbine or LOHC stack provided externally.

[0055] Furthermore, the SOFC module includes a stack housing 1 and a heat insulation tile 2 covering the outside of the stack housing 1; the stack housing 1 is a through-type housing structure with two parallel openings, and a slide rail for slidably installing a plurality of power generation chambers 3 is provided inside the stack housing 1.

[0056] Furthermore, a plurality of convex strips are provided on the inner wall of the stack housing 1, and the ends of the convex strips abut against the outer surface of the power generation chamber 3 entering the stack housing 1 from all around.

[0057] The power generation chamber 3 includes two outer shells that are buckled together. The outer shells are connected and fixed by bolts, and a sealing groove structure and high-temperature resistant caulking are provided at their joints. The inner wall of the outer shell of the power generation chamber 3 has a sunken groove, and a ceramic hollow member 6 is provided in the sunken groove; the ceramic hollow member 6 is of a honeycomb structure, and the fuel gas or air entering the power generation chamber 3 enters the ceramic hollow member 6 and diffuses.

[0058] Further, the outer shell of the power generation chamber 3 is an integral structure made of silicon nitride ceramic material. A diffusion part is formed by thickening the inner wall of the outer shell, and a number of holes that communicate with each other and penetrate the entire diffusion part are dug in the diffusion part to form a ceramic hollowed-out part 6. An air inlet pipe 4 and an exhaust pipe 5 that protrude outward and are integrally formed with the outer shell are provided on the outer wall of the power generation chamber 3. They are communicated with the air inlet pipe 4 and the exhaust pipe 5 through pipelines arranged in the stack shell 1, and the connection points are sealed with high-temperature resistant caulking material.

[0059] Both the air inlet pipe 4 and the exhaust pipe 5 are communicated with the ceramic hollowed-out part 6; when the two outer shells are buckled together, a plate-shaped electrolyte 8 is provided in the middle of the power generation chamber 3 at the buckling part of the outer shell, and electrode plates 7 are provided on both sides of the electrolyte 8 and are attached to the surface of the ceramic hollowed-out part 6.

[0060] Further, the electrolyte 8 in this embodiment and the outer shell of the power generation chamber 3 and the ceramic hollowed-out part 6 are designed with an integral structure in the same position, and an electrode plate 7 structure is provided between the ceramic hollowed-out part 6 and the electrolyte 8. The electrolyte 8 adopts a porous and loose structure, and like the ceramic hollowed-out part 6, it transfers heat to the outer shell for heat exchange.

[0061] In this embodiment, in order to further utilize the waste heat in the SOFC power generation system, the hot air that brings out the heat of the outer shell by the blower is transmitted through a pipeline to the LOHC hydrogen release reactor to heat the hydrogen storage organic liquid inside to maintain its reaction temperature. By adjusting the air volume of the blower and the corresponding size of the LOHC reactor and the liquid capacity, its reaction temperature is maintained between 30 - 50 °C.

[0062] At the same time, the high-pressure gas in each power generation chamber 3 also enters the nearby gas turbine through a separate exhaust pipe 5 for power generation.

[0063] The present invention is not limited to the above optional embodiments, and anyone can obtain other various forms of products under the inspiration of the present invention. The above specific embodiments should not be construed as limiting the protection scope of the present invention. The protection scope of the present invention should be defined by the claims, and the description can be used to interpret the claims.

Claims

1. A SOFC power generation system that reacts by introducing fuel gas and air for power generation, characterized in that: It includes a preheating mechanism and an SOFC module. The SOFC module has a cavity in which a number of independent power generation chambers (3) are installed, and the preheating mechanism is communicated with the cavity of the SOFC module; The preheating mechanism and the SOFC module are simultaneously communicated through an external pipeline for gas supply. The preheating mechanism has a combustion chamber and a blower. Fuel gas and oxygen are introduced into the combustion chamber for combustion and heat generation, and the blower blows air out of the combustion chamber and injects hot air into the cavity of the SOFC module for preheating; A temperature sensor is provided in the power generation chamber (3). When the temperature in the power generation chamber (3) is higher than a set first threshold value, fuel gas and air are introduced through an external pipeline for reaction; When the temperature in more than half of the power generation chambers (3) rises to a second threshold value and remains above the second threshold value within a set time, the combustion chamber of the preheating mechanism is closed; When the temperature in more than half of the power generation chambers (3) rises to a third threshold value and remains above the third threshold value within a set time, the blower is turned on to inject air into the cavity of the SOFC module, and the hot air in the cavity of the SOFC module is introduced into a gas turbine or an LOHC stack provided externally.

2. The SOFC power generation system according to claim 1, wherein: The SOFC module includes a stack shell (1) and a heat insulation tile (2) covering the outside of the stack shell (1); The stack shell (1) is a through-type shell structure with two parallel openings. A slide rail for slidably installing a number of power generation chambers (3) is provided in the stack shell (1).

3. The SOFC power generation system according to claim 2, characterized in that: A number of convex strips are provided on the inner wall of the stack shell (1), and the ends of the convex strips abut against the outer surface of the power generation chamber (3) entering the stack shell (1) from all around.

4. A SOFC power generation system according to any one of claims 1-3, characterized in that: The power generation chamber (3) includes two outer shells that are snap-fitted together. The outer shells are connected and fixed by bolts, and a sealing groove structure and a high-temperature resistant caulking material are provided at their joints.

5. The SOFC power generation system according to claim 4, characterized in that: The inner wall of the outer shell of the power generation chamber (3) has a sunk groove, and a ceramic hollowing member (6) is provided in the sunk groove; The ceramic hollowing member (6) is of a honeycomb structure. The fuel gas or air entering the power generation chamber (3) enters the ceramic hollowing member (6) and diffuses.

6. The SOFC power generation system according to claim 5, characterized in that: The outer shell of the power generation chamber (3) is an integral structure made of silicon nitride ceramic material. A diffusion part is formed by thickening the inner wall of the outer shell, and a number of holes that are interconnected and penetrate the entire diffusion part are dug in the diffusion part to form the ceramic hollowing member (6).

7. A SOFC power generation system according to claim 6, characterized in that: An air inlet pipe (4) and an exhaust pipe (5) that protrude outward and are integrally formed with the outer shell are provided on the outer wall of the power generation chamber (3). They are communicated with the air inlet pipe (4) and the exhaust pipe (5) through pipelines provided in the stack shell (1), and the connection parts are sealed with high-temperature resistant caulking material.

8. A SOFC power generation system according to claim 7, characterized in that: Both the air inlet pipe (4) and the exhaust pipe (5) are communicated with the ceramic hollowing member (6); When the two outer shells are snap-fitted together, a plate-shaped electrolyte (8) is provided in the middle of the power generation chamber (3) at the snap-fitting part of the outer shells, and electrode plates (7) are provided on both sides of the electrolyte (8) and are attached to the surface of the ceramic hollowing member (6).

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