Heat exchanger and solid oxide fuel cell methanol reforming system

Abstract

The application provides a solid oxide fuel cell methanol reforming system, which comprises a heat exchanger, a reformer, a hot oil circulation assembly and a hot oil cooling assembly, and heat conduction oil provided by the heat exchanger is used to heat the reformer to carry out methanol reforming to produce hydrogen, wherein the heat exchanger comprises an air inlet guide element, an air outlet guide element, an oil inlet guide element, an oil outlet guide element, a guide element, a hot oil pressure relief element and an air outlet pipe, the guide element comprises a plurality of parallel arranged flow channel plates, and cold source flow channels and heat source flow channels are formed between adjacent flow channel plates in a spaced manner. The solid oxide fuel cell methanol reforming system in the application uses the heat conduction oil heated by the heat exchanger to heat and carry out reforming to produce hydrogen, the requirement for the tail gas pressure is reduced, the service life of the battery system is greatly improved, the temperature of the heat conduction oil is more easily controlled accurately, the service life of the catalyst in the reformer is prolonged, and the gas flow channels of the heat exchanger are designed in a low flow resistance form, and the requirement for the pressure of the tail gas inlet end is further reduced.

Description

Technical Field

[0001] This invention relates to the field of reforming hydrogen production technology, specifically to a heat exchanger and a methanol reforming system for solid oxide fuel cells. Background Technology

[0002] Currently, traditional hydrogen production reformers in solid oxide fuel cells (SOFCs) typically use mature industrial hydrogen production catalysts, mostly in the form of granular materials similar in size to mung beans or soybeans. The minimum inner diameter of the circular tube filling the catalyst is eight times the diameter of the catalyst. The catalytic hydrogen production reaction is a strongly endothermic reaction. In order to provide sufficient heat to the catalyst-filled tubes, within the limited reformer volume, heat storage materials similar to ceramic beads need to be filled between the catalyst tubes to fully absorb the waste heat from the passing exhaust gas and then transfer it to the catalyst tubes. However, in this type of reformer that directly uses exhaust gas for heating, the gas resistance of the exhaust gas passing through the internal heat exchange chamber of the reformer is relatively large, resulting in a large pressure loss. To operate normally, the exhaust gas pressure at the inlet needs to be increased, directly causing the SOFC stack to withstand a relatively high gas pressure, exceeding the current pressure limit of SOFC stacks. Under high gas pressure, the lifespan of the SOFC stack will be drastically shortened or it will be directly damaged.

[0003] In addition, the methanol reforming hydrogen production in SOFC battery stacks generally uses a low-temperature catalyst of around 250°C, which has a long lifespan and low price. However, if the reforming tube is directly heated by the tail gas during the reforming hydrogen production process, the temperature is not easy to control and the low-temperature catalyst is prone to failure. If a high-temperature resistant methanol-water hydrogen production catalyst is used, it has the disadvantages of being expensive, having a short lifespan, and being prone to carbon buildup, making it unsuitable for long-term system operation. Summary of the Invention

[0004] The purpose of this invention is to provide a methanol reforming system for solid oxide fuel cells (SOFCs) that uses heat transfer oil heated by a heat exchanger for heating. On the one hand, compared with directly heating the reformer with exhaust gas, the requirements for exhaust gas pressure are lower. Given the limited back pressure that SOFC stacks can withstand, this can significantly extend the lifespan of the SOFC system. On the other hand, the temperature of the heat transfer oil is easier to control precisely, making the catalyst in the reformer less susceptible to damage and extending its service life. Furthermore, the gas flow channel of the heat exchanger provided by this invention is designed with low flow resistance, further reducing the pressure requirements at the exhaust gas inlet.

[0005] To achieve the above objectives, the present invention provides a heat exchanger, including an inlet guide, an outlet guide, an oil inlet guide, an oil outlet guide, a flow guide, a hot oil pressure relief component, and an outlet pipe. The flow guide includes multiple parallel flow channel plates, with cold source channels and hot source channels spaced apart between adjacent flow channel plates. The cold source channels include a cold source inlet and a cold source outlet, and the hot source channels include a hot source inlet and a hot source outlet. The oil inlet guide covers the entire cold source inlet, and the oil inlet guide is respectively connected to… The cold source inlet and the hot oil pressure relief component are connected. The oil outlet guide covers all the cold source outlets and is connected to all the cold source outlets. The air inlet guide is located below the guide and is connected to all the hot source inlets. The air outlet guide is located above the guide and is connected to all the hot source outlets. The hot oil pressure relief component is located above the air outlet guide and is connected to the oil inlet guide. The air outlet pipe passes through the hot oil pressure relief component and is connected to the air outlet guide.

[0006] The heat exchanger of the present invention has an alternating low flow resistance internal flow channel design, which can reduce the demand on the gas pressure at the inlet end. The heat exchanger exchanges heat between the heat transfer oil and the combustion exhaust gas provided by the battery stack. The heat transfer oil has a high heat capacity, and the heating is stable and uniform, which improves the heat exchange efficiency.

[0007] Furthermore, each flow channel plate of the flow guide includes a plate body and flow guide plates, with the flow guide plates forming a cold source flow channel and a hot source flow channel on both sides of the plate body, respectively.

[0008] Furthermore, the cold source flow channel is surrounded by four guide vanes covering the four edges of one side of the plate. The four guide vanes are connected end to end in pairs. Only part of the two edges of the plate in the length direction are covered, and there is a gap between them and the guide vanes located on the edge in the width direction of the plate. The gap at one end serves as the cold source inlet, and the gap at the other end serves as the cold source outlet.

[0009] Furthermore, the heat source channel is formed by two guide vanes covering the two sides of the other side of the plate along its length, and the two sides of the plate not covered by the guide vanes serve as the heat source inlet and heat source outlet, respectively.

[0010] The cold source flow channel and the hot source flow channel designed in this invention are arranged in parallel and spaced apart. The flow channel surrounded by guide plates has a large heat exchange contact area and higher heat exchange efficiency.

[0011] Furthermore, the hot oil pressure relief component is equipped with an oil inlet pipe and an exhaust pipe. The oil inlet pipe is used to add heat transfer oil to the entire reforming system, and air is very easy to mix in during the process of adding heat transfer oil. The exhaust pipe is used to expel the air from the hot oil pressure relief component.

[0012] Furthermore, the hot oil pressure relief component is equipped with a level gauge. The level gauge is used to monitor the liquid level of the heat transfer oil in the hot oil pressure relief component.

[0013] Furthermore, thermocouples are provided on the gas outlet guide, the oil outlet guide, and the hot oil pressure relief component. The thermocouples are used to monitor the temperature inside each guide and the hot oil pressure relief component.

[0014] The present invention also provides a methanol reforming system for a solid oxide fuel cell, comprising:

[0015] Heat exchangers are used to heat heat transfer oil;

[0016] A reformer is used to reform methanol to produce hydrogen.

[0017] A hot oil circulation assembly includes a hot oil circulation pump, a circulation pump inlet pipe, and a circulation pump outlet pipe. The circulation pump inlet pipe is connected to the reformer, and the circulation pump outlet pipe is connected to the hot oil pressure relief component of the heat exchanger.

[0018] A hot oil cooling assembly includes an oil guide pipe, a cooling pipe, a water inlet pipe, and a water outlet pipe. The oil guide pipe is connected to the oil outlet guide of the heat exchanger and the reformer, respectively. The cooling pipe is sleeved outside the oil guide pipe for cooling the oil guide pipe. The water inlet pipe and the water outlet pipe are connected to the cooling pipe.

[0019] The solid oxide fuel cell methanol reforming system provided by this invention uses heat transfer oil heated by a heat exchanger for heating. The temperature of the heat transfer oil entering the reformer can be precisely controlled by the hot oil cooling component, which makes the catalyst in the reformer less prone to damage and extends the service life of the catalyst.

[0020] Furthermore, a thermocouple is installed at the connection point between the reformer and the oil guide pipe. This thermocouple is used to monitor the temperature of the heat transfer oil entering the reformer in real time, preventing the heat transfer oil temperature from becoming too high and causing the catalyst in the reformer to degrade.

[0021] Furthermore, an oil drain pipe is provided on the oil inlet pipe of the circulating pump. The oil drain pipe is used to drain the heat transfer oil in the entire reforming system.

[0022] Compared with other existing technologies, the present invention has the following beneficial effects:

[0023] (1) The heat exchanger of the present invention is designed with alternating low flow resistance flow channels, which can reduce the demand for gas pressure at the inlet end. The heat exchanger exchanges heat between the heat transfer oil and the combustion exhaust gas provided by the battery stack. The heat transfer oil has high heat capacity, and the heating is stable and uniform, which improves the heat exchange efficiency.

[0024] (2) The cold source flow channel and the heat source flow channel designed in this invention are arranged in parallel and spaced apart. The flow channel surrounded by the guide plate has a large heat exchange contact area and higher heat exchange efficiency.

[0025] (3) The solid oxide fuel cell methanol reforming system provided by the present invention uses heat transfer oil heated by a heat exchanger for heating. Compared with directly using tail gas to heat the reformer, the requirements for tail gas pressure are lower. Under the condition that the back pressure of SOFC battery stack is limited, the life of SOFC system can be greatly improved. The temperature of the heat transfer oil entering the reformer can be precisely controlled by the hot oil cooling component, so that the catalyst in the reformer is not easily damaged and the service life of the catalyst is extended. Attached Figure Description

[0026] Figure 1 This is a three-dimensional structural diagram of the heat exchanger and the methanol reforming system for a solid oxide fuel cell in an embodiment of the present invention.

[0027] Figure 2 This is a three-dimensional structural diagram of the heat exchanger in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the cold source flow channel structure in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the heat source flow channel structure in an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the flow channel plate stacking process in an embodiment of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1-Inlet air guide, 2-Outlet air guide, 3-Inlet oil guide, 4-Outlet oil guide, 5-Guide, 501-Plate, 502-Guide plate, 503-Cold source inlet, 504-Cold source outlet, 505-Heat source inlet, 506-Heat source outlet, 510-Cold source flow channel, 511-Heat source flow channel, 6-Hot oil pressure relief component, 601-Inlet oil pipe, 602-Exhaust pipe, 603-Level gauge, 7-Outlet air pipe, 8-Thermocouple, 9-Reformer, 10-Hot oil circulation assembly, 101-Hot oil circulation pump, 102-Circulation pump inlet oil pipe, 103-Circulation pump outlet oil pipe, 104-Drain oil pipe, 11-Hot oil cooling assembly, 111-Oil guide pipe, 112-Cooling pipe, 113-Water inlet pipe, 114-Water outlet pipe. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0035] It should be noted that similar symbols and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "inner," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0038] Combination Figure 1 As shown, this embodiment of the invention provides a heat exchanger, including an inlet guide 1, an outlet guide 2, an oil inlet guide 3, an oil outlet guide 4, a guide vane 5, a hot oil pressure relief component 6, and an outlet pipe 7. The guide vane 5 includes multiple parallel flow channel plates, each flow channel plate including a plate body 501 and guide vanes 502. The guide vanes 502 form a cold source flow channel 510 and a hot source flow channel 511 on both sides of the plate body 501, respectively. The cold source flow channel 510 and the hot source flow channel 511 between adjacent flow channel plates are spaced apart, such as... Figure 3As shown, the cold source flow channel 510 is surrounded by four guide vanes 502 covering the four edges of one side of the plate 501. The four guide vanes 502 are connected end-to-end in pairs. The two edges of the plate 501 in the width direction are completely covered, while only the two edges in the length direction are partially covered, with gaps between them and the guide vanes 502 located on the width edge of the plate 501. One gap serves as the cold source inlet 503, and the other gap serves as the cold source outlet 504. Figure 4 As shown, the heat source channel 511 is formed by two guide vanes 502 covering the two sides of the other side of the plate 501 along the length direction. The guide vanes 502 completely cover the two sides of the plate 501 along the length direction. The two sides of the plate 501 that are not covered by the guide vanes 502 in the width direction serve as the heat source inlet 505 and the heat source outlet 506, respectively. The heat exchange contact area of ​​the cold source channel 510 and the heat source channel 511 formed by the guide vanes 502 on the plate 501 is large, and the heat exchange efficiency is higher.

[0039] Combination Figure 5 As shown, two adjacent flow channel plates are stacked together with their same flow channel side in contact to form parallel flow channel plates. The cold source flow channels 510 of the two adjacent flow channel plates are mirror images, so that the guide plates 502 of the two adjacent flow channel plates completely overlap when stacked. The cold source flow channels 510 and the heat source flow channels 511 in the flow guide 5 are arranged in parallel and spaced apart.

[0040] Combination Figure 2 As shown, the oil inlet guide 3 covers the entire cold source inlet 503 and is connected to both the cold source inlet 503 and the hot oil pressure relief component 6. The oil outlet guide 4 covers the entire cold source outlet 504 and is connected to both the cold source outlet 504. The air inlet guide 1 is located below the guide 5 and is connected to both the hot source inlet 505. The air outlet guide 2 is located above the guide 5 and is connected to both the hot source outlet 506. After passing through the inlet guide 1, the source gas enters the heat source channel 511 from the heat source inlet 505. The hot oil pressure relief component 6 is located above the outlet guide 2 and is connected to the oil inlet guide 3. The heat transfer oil in the hot oil pressure relief component 6 enters the cold source channel 510 from the cold source inlet 503 after passing through the oil inlet guide 3. The outlet pipe 7 passes through the hot oil pressure relief component 6 and is connected to the outlet guide 2, so that the source gas in the outlet guide 2 is discharged from the heat exchanger through the outlet pipe 7.

[0041] Combination Figure 1 and Figure 2 As shown, the hot oil pressure relief component 6 is equipped with an oil inlet pipe 601 and an exhaust pipe 602. The oil inlet pipe 601 is used to add heat transfer oil to the entire reforming system. However, air is very easy to get mixed in during the process of adding heat transfer oil. The exhaust pipe 602 is used to discharge the air mixed in with the hot oil pressure relief component 6.

[0042] Furthermore, as a preferred embodiment, the hot oil pressure relief component 6 is equipped with a level gauge 603.

[0043] Furthermore, as a preferred embodiment, thermocouples 8 are provided on the air outlet guide 2, the oil outlet guide 4, and the hot oil pressure relief component 6.

[0044] This invention also provides a methanol reforming system for a solid oxide fuel cell, including the aforementioned heat exchanger, reformer 9, hot oil circulation assembly 10, and hot oil cooling assembly 11, combined with... Figure 1 As shown, the hot oil circulation assembly 10 is used to circulate the heat transfer oil throughout the reforming system. It includes a hot oil circulation pump 101, a circulation pump inlet pipe 102, and a circulation pump outlet pipe 103. The circulation pump inlet pipe 102 is connected to the reformer 9, and the circulation pump outlet pipe 103 is connected to the hot oil pressure relief component 6 of the heat exchanger. The hot oil cooling assembly 11 includes an oil guide pipe 111, a cooling pipe 112, a water inlet pipe 113, and a water outlet pipe 114. The oil guide pipe 111 is connected to the oil outlet guide component 4 of the heat exchanger and the reformer 9, respectively. The cooling pipe 112 is sleeved outside the oil guide pipe 111 for cooling the oil guide pipe 111. The water inlet pipe 113 and the water outlet pipe 114 are connected to the cooling pipe 112.

[0045] Furthermore, as a preferred embodiment, a thermocouple is provided at the position where the reformer 9 connects to the oil guide pipe 111.

[0046] Furthermore, as a preferred embodiment, an oil drain pipe 104 is provided on the oil inlet pipe 102 of the circulating pump.

[0047] In this embodiment, the heat transfer oil circulation process of the methanol reforming system in a solid oxide fuel cell is as follows: After the hot oil circulation pump 101 starts operating, the heat transfer oil is forced into the hot oil pressure relief component 6 through the circulation pump outlet pipe 103. The hot oil pressure relief component 6 relieves the pressure of the incoming heat transfer oil. After the pressure is relieved, the heat transfer oil passes through the oil inlet guide component 3 and enters the cold source flow channel 510 from the cold source inlet 503. In the cold source flow channel 510, it exchanges heat with the combustion exhaust gas of the fuel cell system in the spaced-apart hot source flow channels 511. The heated heat transfer oil... Hot oil flows out from the cold source outlet 504, passes through the oil outlet guide 4, and enters the oil guide pipe 111. The temperature of the heat transfer oil is monitored by the thermocouple 8 on the oil outlet guide 4. If the temperature is too high, the oil guide pipe 111 can be cooled by the cooling pipe 112 in the high-temperature cooling assembly 11. After the temperature of the heat transfer oil in the oil guide pipe 111 reaches the required level, it enters the reformer 9 for methanol reforming to produce hydrogen. After use, the cooled heat transfer oil flows out from the circulation pump inlet pipe 102 and returns to the hot oil circulation pump 101, completing the entire circulation process. Testing shows that the solid oxide fuel cell methanol reforming system of this invention achieves a utilization rate of over 90% for the combustion exhaust gas provided by the solid oxide fuel cell stack system.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A methanol reforming system for a solid oxide fuel cell, characterized in that, include: A heat exchanger is used to heat heat transfer oil. The heat exchanger includes an inlet guide (1), an outlet guide (2), an oil inlet guide (3), an oil outlet guide (4), a guide (5), a hot oil pressure relief component (6), and an outlet pipe (7). The guide (5) includes multiple parallel flow channel plates. The flow channel plate includes a plate body (501) and guide vanes (502) disposed on the plate body (501). The guide vanes (502) form a cold source flow channel (510) and a heat source flow channel (511) on both sides of the plate body (501), respectively. The cold source flow channel (510) and the heat source flow channel (511) are spaced apart between adjacent flow channel plates. The cold source flow channel (510) includes a cold source inlet (503) and a cold source outlet (504). The heat source flow channel (511) includes a heat source inlet (505) and a heat source outlet. The oil inlet guide (3) covers all the cold source inlets (503), and the oil inlet guide (3) is connected to the cold source inlets (503) and the hot oil pressure relief device (6) respectively. The oil outlet guide (4) covers all the cold source outlets (504), and the oil outlet guide (4) is connected to all the cold source outlets (504). The air inlet guide (1) is located below the guide (5) and is connected to all the heat source inlets (505). The air outlet guide (2) is located above the guide (5) and is connected to all the heat source outlets (506). The hot oil pressure relief device (6) is located above the air outlet guide (2) and is connected to the oil inlet guide (3). The air outlet pipe (7) passes through the hot oil pressure relief device (6) and is connected to the air outlet guide (2). Reformer (9) is used to reform methanol to produce hydrogen; The hot oil circulation assembly (10) includes a hot oil circulation pump (101), a circulation pump inlet pipe (102) and a circulation pump outlet pipe (103). The circulation pump inlet pipe (102) is connected to the reformer (9), and the circulation pump outlet pipe (103) is connected to the hot oil pressure relief component (6) of the heat exchanger. The hot oil cooling assembly (11) includes an oil guide pipe (111), a cooling pipe (112), a water inlet pipe (113), and a water outlet pipe (114). The oil guide pipe (111) is connected to the oil outlet guide (4) of the heat exchanger and the reformer (9) respectively. The cooling pipe (112) is sleeved on the outside of the oil guide pipe (111) for cooling the oil guide pipe (111). The water inlet pipe (113) and the water outlet pipe (114) are connected to the cooling pipe (112).

2. The methanol reforming system for a solid oxide fuel cell as described in claim 1, characterized in that, The cold source flow channel (510) is surrounded by four guide vanes (502) on the four sides of one side of the covering plate (501). The four guide vanes (502) are connected end to end in pairs. Only part of the two sides of the plate (501) in the length direction are covered, and there is a gap between them and the guide vanes (502) on the width direction edge of the plate (501). The gap at one end serves as the cold source inlet (503), and the gap at the other end serves as the cold source outlet (504).

3. The methanol reforming system for a solid oxide fuel cell as described in claim 1, characterized in that, The heat source channel (511) is surrounded by two guide vanes (502) covering the two edges of the plate (501) along the length direction on the other side. The two sides of the plate (501) not covered by the guide vanes (502) serve as the heat source inlet (505) and the heat source outlet (506), respectively.

4. The solid oxide fuel cell methanol reforming system as described in claim 1, characterized in that, The hot oil pressure relief component (6) is provided with an oil inlet pipe (601) and an exhaust pipe (602).

5. The methanol reforming system for a solid oxide fuel cell as described in claim 1, characterized in that, The hot oil pressure relief component (6) is equipped with a level gauge (603).

6. The methanol reforming system for a solid oxide fuel cell as described in claim 1, characterized in that, Thermocouples (8) are provided on the air outlet guide (2), the oil outlet guide (4) and the hot oil pressure relief component (6).

7. The methanol reforming system for a solid oxide fuel cell as described in claim 1, characterized in that, A thermocouple is provided at the position where the reformer (9) connects to the oil guide pipe (111).

8. The methanol reforming system for a solid oxide fuel cell as described in claim 1, characterized in that, An oil drain pipe (104) is provided on the oil inlet pipe (102) of the circulating pump.

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