Pipeline heat insulation and waste heat recovery device for high-temperature fuel cell system

Abstract

The utility model relates to the technical field of tail gas treatment, and discloses a pipeline heat insulation and waste heat recovery device for a high-temperature fuel cell system, which comprises a high-temperature flue gas inlet assembly, a circulating water heat exchange assembly and a heat exchange cavity assembly, the high-temperature flue gas inlet assembly is sleeved with the circulating water heat exchange assembly, the circulating water heat exchange assembly is sleeved with the heat exchange cavity assembly, the high-temperature flue gas inlet assembly, the circulating water heat exchange assembly and the heat exchange cavity assembly are sequentially connected in a nested mode to form a heat exchange body, and all the parts are sealed through flanges. And the heat insulation sealing material with a certain thickness is arranged between the sealing flanges, direct contact is avoided, and heat conduction between parts can be effectively reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of tail gas treatment, and in particular to a pipeline heat insulation and waste heat recovery device for a high-temperature fuel cell system. Background Art

[0002] Solid oxide fuel cell (SOFC) is a power generation and heating device that operates in a high temperature environment. It is a device that converts fuel chemical energy into electrical energy based on the principle of battery reaction. It has the characteristics of high power generation efficiency, low operating noise, and stable equipment operation. However, due to the high operating temperature, good thermal insulation measures are required to avoid excessive heat dissipation, which leads to a decrease in overall efficiency. In particular, for small-scale SOFC power generation systems, due to their low self-heating power, environmental heat dissipation has a particularly significant impact on their efficiency.

[0003] SOFC power generation systems are usually equipped with thicker insulation outer walls to reduce environmental heat dissipation losses. Due to the limitations of the system and heat exchange process, flue gas with a temperature higher than room temperature will be generated during the operation of the power generation system. In order to improve the operating efficiency of the high-temperature system, a gas-liquid heat exchanger can be used to recover the waste heat in the tail gas.

[0004] However, the temperature stability of the high-temperature hot zone of the system is a key factor in maintaining reliable operation. Therefore, for the waste heat recovery device, it is necessary to recover the heat in the flue gas while minimizing the heat consumption of other components in the hot zone. In the hot zone of the system, there are high-temperature burners, reformers, and high-temperature flue gas heat exchange groups. At this time, the heat transfer of metal pipes, convection heat transfer in the hot zone, and radiation heat transfer will cause the heat in the hot zone to be transferred to the relatively low-temperature waste heat recovery device.

[0005] Placing the waste heat recovery device externally can alleviate the problem of heat loss in the hot zone to a certain extent. However, since the high-temperature pipelines that transport high-temperature flue gas will pass through the room temperature environment, on the one hand, the heat dissipation will reduce the temperature of the flue gas itself, resulting in an increase in the equipment environment temperature and a decrease in the heat recovery amount; on the other hand, due to the heat conduction of the metal pipes, the heat inside the hot zone to maintain the high temperature will also be lost.

[0006] The above phenomenon is particularly significant for small-scale SOFC power generation systems. Due to its low self-heating, if the waste heat recovery device absorbs the heat of other components in the hot zone due to heat transfer in the pipeline, convection heat transfer in the hot zone, radiation heat transfer, etc., the power of the built-in heating components (such as burners, electric heaters, etc.) will increase significantly, ultimately resulting in a serious low power generation efficiency of the system as a whole. Utility Model Content

[0007] The purpose of the utility model is to solve the problem that the existing high-temperature fuel cell (SOFC) and other systems involving high-temperature exhaust gas emissions, whose exhaust gas emissions and waste heat recovery devices are prone to heat transfer, lead to additional heat loss in the high-temperature area. A pipeline insulation and waste heat recovery device for a high-temperature fuel cell system is proposed.

[0008] The technical solution of the utility model is as follows:

[0009] A pipeline insulation and waste heat recovery device for a high-temperature fuel cell system, comprising a high-temperature flue gas intake component, a circulating water heat exchange component and a heat exchange cavity component; the circulating water heat exchange component is sleeved on the outside of the high-temperature flue gas intake component, the heat exchange cavity component is sleeved on the outside of the circulating water heat exchange component, one end of the high-temperature flue gas intake component extends out of the heat exchange cavity component, the other end extends into the circulating water heat exchange component, and the high-temperature flue gas intake component and one end of the heat exchange cavity component are insulated and sealed (a certain thickness of insulation sealing material is provided between the sealing flanges); one end of the circulating water heat exchange component extends into the heat exchange cavity component, the other end extends out of the heat exchange cavity component, and the circulating water heat exchange component and the other end of the heat exchange cavity component are insulated and sealed.

[0010] Furthermore, the heat exchange cavity assembly includes a heat exchange cavity shell, and square sealing flanges are provided at both ends of the heat exchange cavity shell, and thermal insulation sealing gaskets are affixed thereto; an exhaust outlet (smoke exhaust duct) is provided on the end of the heat exchange cavity shell away from the air outlet of the high-temperature flue gas inlet assembly, and a smoke exhaust flange is provided.

[0011] Furthermore, the high-temperature flue gas intake assembly includes a flue gas intake pipe, one end of which is penetrated by a square sealing flange of the intake pipe, and the length of the smoke gas intake pipe extending out of the square sealing flange of the intake pipe is shorter than the length of the outer shell of the heat exchange cavity, and a high-temperature flue gas intake flange is provided on the end of the smoke gas intake pipe near one end of the square sealing flange of the intake pipe.

[0012] Furthermore, the circulating water heat exchange component includes a heat exchange spiral tube, the inlet and outlet of the heat exchange spiral tube are located on the same side, and are penetrated by a circulating water square sealing flange. After the inlet and outlet of the heat exchange spiral tube pass through the circulating water square sealing flange, they are respectively connected to a three-way conversion joint, wherein one interface of the three-way conversion joint is inserted with a temperature measuring thermocouple, which can be used to monitor the circulating water inlet temperature and the circulating water outlet temperature, and the other interface is correspondingly connected to the circulating water inlet pipe and the circulating water outlet pipe.

[0013] Furthermore, a pipeline insulation and waste heat recovery device for a high-temperature fuel cell system also includes an insulating box body, which is equipped with an insulating box cover plate, and the heat exchange recovery body composed of the high-temperature flue gas intake assembly, the circulating water heat exchange assembly and the heat exchange cavity assembly is placed in a sealed cavity composed of the insulating box body and the insulating box cover plate.

[0014] Furthermore, the thermal insulation box body includes a box metal frame and ceramic fiber insulation material boards arranged at the bottom and around the box metal frame; the thermal insulation box cover includes a cover metal frame and a top insulation board arranged on the cover metal frame.

[0015] Furthermore, a small hole is opened on the lower side of the shell of the heat exchange cavity, and is connected to a drainage pipeline for timely discharge of condensed water.

[0016] Furthermore, the high-temperature flue gas inlet pipe is provided with annular fins for increasing the flow path of the high-temperature flue gas, increasing the gas flow rate, and enhancing the heat exchange performance.

[0017] Furthermore, the heat exchange spiral tube is provided with annular fins to increase the gas heat exchange area, guide the flow of high-temperature flue gas, and improve the flue gas waste heat recovery performance.

[0018] Furthermore, a pipeline insulation and waste heat recovery device for a high-temperature fuel cell system is provided, which is used in a high-temperature solid oxide fuel cell SOFC system, and the device is built inside the hot zone of the SOFC system, with its top being in contact with the inner wall of the SOFC hot zone insulation top plate.

[0019] The beneficial effects of the utility model are as follows:

[0020] 1) The high-temperature flue gas intake assembly, circulating water heat exchange assembly, and heat exchange cavity assembly of the utility model are nested and connected in sequence to form a heat exchange main body. Flanges are used to seal the components, and a certain thickness of heat-insulating sealing material is provided between the sealing flanges. There is no direct contact, which can effectively reduce heat conduction between components.

[0021] 2) The utility model avoids additional heat loss caused by heat conduction. At the same time, a certain thickness of heat insulation material is provided on the outside of the heat exchange body to avoid heat transfer to the exhaust pipe due to heat radiation and convection in the hot zone.

[0022] 3) The utility model blocks direct heat conduction of smoke inlet, smoke outlet and water exchange water circuit components, blocks direct heat transfer from hot zone components to exhaust gas discharge pipe, and simultaneously utilizes exhaust gas-water heat exchange to reduce the temperature of exhaust pipe outlet, effectively reduces the heat dissipation effect from the end of the pipe to the room temperature environment, and improves the overall efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a three-dimensional structural schematic diagram of the heat insulation and waste heat recovery device of the utility model;

[0024] Figure 2 It is a schematic diagram of the assembly of components of the heat insulation and waste heat recovery device of the utility model;

[0025] Figure 3 This is a schematic diagram of the structure of the heat insulation and waste heat recovery device of the utility model after removing the heat preservation box;

[0026] Figure 4 This is a schematic diagram of the structure of the heat insulation and waste heat recovery device of the utility model after removing the heat exchange cavity shell;

[0027] Figure 5 This is a schematic diagram of the structure of the heat-insulating box body and the heat-insulating box cover of the utility model;

[0028] Figure 6 It is a two-dimensional transverse cross-sectional schematic diagram of the heat insulation and waste heat recovery device of the utility model;

[0029] Figure 7 It is a two-dimensional longitudinal cross-sectional schematic diagram of the heat insulation and waste heat recovery device of the utility model;

[0030] In the figure: 1. Circulating water heat exchange assembly; 101. Circulating water outlet pipe; 102. Circulating water inlet pipe; 103. Heat exchange spiral tube; 104. Circulating water square sealing flange; 105. Three-way conversion joint; 106. Temperature measuring thermocouple; 2. Heat insulation sealing gasket; 3. Heat insulation box; 301. Box metal frame; 302. Flue gas side insulation board; 303. Insulation side board; 304. Circulating water side insulation board; 305. Bottom support insulation board; 4. High-temperature flue gas inlet assembly; 401. High-temperature flue gas inlet flange; 402. Flue gas inlet pipe; 403. Square sealing flange of inlet pipe; 5. Heat exchange cavity assembly; 501. Flue gas exhaust flange; 502. Heat exchange cavity shell; 503. Square sealing flange; 6. Heat insulation box cover; 601. Cover metal frame; 602. Top insulation board. DETAILED DESCRIPTION

[0031] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0032] A pipeline insulation and waste heat recovery device for a high-temperature fuel cell system comprises a horizontally placed left and right connected heat exchange cavity shell, flange structures are provided at the openings on both sides of the heat exchange cavity shell, and heat insulation sealing gaskets of a certain thickness are affixed to block direct heat conduction between connected components, an exhaust port is opened near the left end of the heat exchange cavity shell, and a flue gas exhaust pipe and a flange are arranged.

[0033] The left side of the heat exchange cavity shell is connected to the high-temperature flue gas inlet assembly, which has a small opening in the center of the flange, through which a metal pipe is passed and sealed. One end of the pipe is provided with a flange for connecting the flue gas pipeline in the system; the other end extends slightly less than the length of the heat exchange cavity shell, and is used to guide the high-temperature flue gas into the heat exchange cavity shell.

[0034] The right side of the heat exchange cavity shell is connected to the circulating water heat exchange component, and a heat exchange spiral tube is installed on its connecting flange. The winding height of the heat exchange spiral tube is slightly lower than the height of the heat exchange cavity shell (to ensure that the heat exchange spiral tube can be normally placed in the heat exchange cavity); the winding size of the heat exchange spiral tube needs to ensure that the internal hollow can accommodate the high-temperature flue gas inlet pipe, and the whole can be placed in the heat exchange cavity shell.

[0035] The inlet and outlet ports of the heat exchange spiral tube are used for the entry and discharge of circulating water respectively, and are equipped with temperature measuring thermocouples to monitor the circulating water temperature.

[0036] The heat exchange cavity shell is placed in an insulation box made of insulation material, and an appropriate amount of insulation cotton is filled in the gap. The smoke exhaust pipe and the circulating water inlet and outlet pipes are all led out from the top of the insulation box. When the insulation and waste heat recovery device is installed in a high-temperature system, the upper surface of the insulation box is attached to the system insulation top plate to prevent the smoke exhaust pipe and circulating water from being affected by the radiation and convection heat exchange of the high-temperature hot zone.

[0037] During the operation of the heat insulation and waste heat recovery device, the high-temperature flue gas enters the heat exchange cavity shell along the high-temperature flue gas inlet assembly, completes heat exchange with the heat exchange spiral tube in the space between the flue gas inlet pipe and the heat exchange cavity shell, and then leaves the waste heat recovery device from the flue gas discharge pipe. The circulating water enters the equipment along the water inlet pipeline, is heated by the high-temperature flue gas in the heat exchange spiral tube, and leaves the device along the water outlet pipeline to achieve waste heat recovery of the high-temperature flue gas.

[0038] The heat insulation and waste heat recovery device is placed inside the high-temperature system. The high-temperature flue gas inlet pipe, flue gas exhaust pipe, and circulating water inlet and outlet pipes are isolated from each other by a certain thickness of heat insulation sealing material, which effectively avoids the mutual heat conduction effect. At the same time, the circulating water inlet and outlet pipes mainly exchange heat with the high-temperature flue gas, reducing the heat transfer effect of the system hot zone and other components on the circulating water circuit, and avoiding additional heat loss in the system.

[0039] A small hole is opened at the bottom of the heat exchange cavity shell of the heat insulation and waste heat recovery device and is sealed and connected to the condensate drainage pipeline. When the flue gas contains a lot of water and condensate continues to accumulate after heat exchange, the excess condensate in the heat exchange cavity can be discharged in time to maintain the stable operation of the waste heat recovery device.

[0040] Auxiliary heat exchange fins or baffles can be installed on the outside of the flue gas inlet duct of the heat insulation and waste heat recovery device, as well as the outer wall of the circulating water spiral tube, to adjust the flow path of the high-temperature flue gas and improve its heat exchange effect.

[0041] Example

[0042] exist Figures 1 to 7 In the embodiment 1 shown, an exhaust gas insulation and waste heat recovery device for a high-temperature fuel cell system, the main body of which includes a cylindrical heat exchange cavity shell 502, with square sealing flanges 503 welded at both ends of the shell. In addition, an exhaust gas discharge port (smoke discharge pipe) is provided near the left side of the heat exchange cavity shell, and a smoke exhaust flange 501 is welded.

[0043] The left side of the heat exchange cavity component 5 is flange-connected to the high-temperature flue gas inlet component 4, and its main structure has a square sealing flange 403 for the inlet pipe, and a flue gas inlet pipe 402 is fixed in the middle of the flange, and the length of the inlet pipe square sealing flange 403 is slightly shorter than the length of the heat exchange cavity shell 502. The other end of the flue gas inlet pipe 402 is sealed and fixed with a high-temperature flue gas inlet flange 401. In order to facilitate the alignment of the flange holes and the fixing of the bolt holes, the flange can be a slip-on flange.

[0044] On the right side of the heat exchange cavity component 5, the circulating water heat exchange component 1 is flange-connected. Its main structure includes a circulating water square sealing flange 104 with a hole in the middle of the flange, and a welded sealed heat exchange spiral tube 103 for waste heat recovery of high-temperature flue gas. The winding height of the heat exchange spiral tube is slightly lower than the height of the heat exchange cavity component 5 to ensure that there is no size conflict when assembling the components. After the inlet and outlet of the spiral tube pass through the square flange, they are each connected to a three-way conversion joint 105, and then vertically connected to the circulating water inlet pipe 102 and the circulating water outlet pipe 101 respectively. In addition, a temperature measuring thermocouple 106 is inserted into the three-way conversion joint, which can be used to monitor the inlet and outlet temperatures of the circulating water to avoid improper flow, water temperature close to boiling temperature, and the risk of potential drastic volume expansion.

[0045] The above-mentioned main heat exchange components are placed in an insulating box body 3, and an insulating box cover plate 6 is provided to reduce the influence of the ambient temperature on the heat exchange components. The main body of the insulating box body 3 includes a box metal frame 301, and the bottom and surrounding parts of the frame are respectively provided with a certain thickness of ceramic fiber insulation material (i.e., flue gas side insulation plate 302, insulation side plate 303, circulating water side insulation plate 304, bottom support insulation plate 305), which are used for insulation and support fixation of the main heat exchange components. The structure of the insulating top plate 6 is similar to that of the above-mentioned insulating box body 3, including a cover metal frame 601 and a top insulation plate 602. After the main heat exchange components are placed in the insulating box body 3, a certain amount of insulation material can be filled in the gaps to assist the fixation and insulation of the device. Finally, the insulating top plate is covered and fixed with a metal frame.

[0046] During the operation of the device, the flue gas inlet flange 401 is connected to the flue gas pipeline in the system, and the high-temperature flue gas enters the heat exchange cavity along the flue gas inlet pipe 402, and is deflected at the circulating water square flange 104, entering the area sandwiched between the flue gas inlet pipe 402 and the heat exchange cavity shell 502, and sweeping the outer wall of the heat exchange spiral tube 103 here. The circulating water enters the leftmost side of the heat exchange spiral tube 103 along the circulating water inlet pipe 102, and conducts convection heat exchange with the high-temperature flue gas to achieve the waste heat recovery effect. After the waste heat recovery is completed, the flue gas leaves the exhaust gas insulation and waste heat recovery device from the flue gas exhaust flange 501.

[0047] The above-mentioned heat insulation and waste heat recovery device is different from conventional gas-liquid heat exchangers. There is no direct metal contact between the flue gas intake pipeline, the flue gas exhaust pipeline, and the heat recovery circulating water pipeline, which reduces the heat conduction effect between high-temperature metals and avoids heat loss of high-temperature components in the hot zone. The device can be placed inside the high-temperature hot zone of the solid oxide fuel cell (SOFC) system that emits flue gas, and its top insulation board is close to the insulation top plate of the hot zone. It can effectively reduce the temperature of the flue gas and the exhaust pipeline, and the appropriate insulation design reduces the heat loss in the hot zone of the system.

[0048] The technical solution in the embodiment of the utility model provides a pipeline insulation and waste heat recovery device. The device can be built into the hot zone of the solid oxide fuel cell (SOFC) system or other hot zones of the system containing high-temperature flue gas emissions. On the one hand, the flue gas waste heat recovery is achieved by using the flue gas-circulating water convection heat exchange. On the other hand, the flue gas inlet and outlet pipes and the main heat exchange components in the device are separated by insulation materials, and the outer shell is provided with thicker insulation materials, which effectively reduces convection and radiation in the hot zone, and heat conduction of metal pipes, avoiding additional heat loss in the hot zone of the system.

Claims

1. A pipeline insulation and waste heat recovery device for a high-temperature fuel cell system, characterized in that: The invention comprises a high-temperature flue gas intake component (4), a circulating water heat exchange component (1) and a heat exchange cavity component (5); the circulating water heat exchange component (1) is sleeved on the outside of the high-temperature flue gas intake component (4), the heat exchange cavity component (5) is sleeved on the outside of the circulating water heat exchange component (1), one end of the high-temperature flue gas intake component (4) extends out of the heat exchange cavity component (5), and the other end extends into the circulating water heat exchange component (1), and the high-temperature flue gas intake component (4) and one end of the heat exchange cavity component (5) are thermally insulated and sealed; one end of the circulating water heat exchange component (1) extends into the heat exchange cavity component (5), and the other end extends out of the heat exchange cavity component (5), and the circulating water heat exchange component (1) and the other end of the heat exchange cavity component (5) are thermally insulated and sealed.

2. The pipeline insulation and waste heat recovery device for a high-temperature fuel cell system according to claim 1, characterized in that: The heat exchange cavity assembly (5) comprises a heat exchange cavity shell (502), and square sealing flanges (503) are provided at both ends of the heat exchange cavity shell (502), and a heat insulating sealing gasket (2) is attached thereto; an exhaust outlet is provided at one end of the heat exchange cavity shell (502) away from the outlet of the high-temperature flue gas inlet assembly (4), and a flue gas exhaust flange (501) is provided.

3. The pipeline insulation and waste heat recovery device for a high-temperature fuel cell system according to claim 1, characterized in that: The high-temperature flue gas intake assembly (4) comprises a flue gas intake pipe (402), one end of which is provided with a square intake pipe sealing flange (403), and the length of the flue gas intake pipe (402) extending out of the square intake pipe sealing flange (403) is shorter than the length of the heat exchange cavity shell (502), and a high-temperature flue gas intake flange (401) is provided on the end of the flue gas intake pipe (402) close to one end of the square intake pipe sealing flange (403).

4. The pipeline insulation and waste heat recovery device for a high-temperature fuel cell system according to claim 1, characterized in that: The circulating water heat exchange component (1) comprises a heat exchange spiral tube (103), the inlet and outlet of the heat exchange spiral tube (103) are located on the same side, and are penetrated by a circulating water square sealing flange (104). After the inlet and outlet of the heat exchange spiral tube (103) pass through the circulating water square sealing flange (104), they are respectively connected to a three-way conversion joint (105), wherein one interface of the three-way conversion joint (105) is inserted with a temperature measuring thermocouple (106) for monitoring the circulating water inlet temperature and the circulating water outlet temperature, and the other interface is correspondingly connected to a circulating water inlet pipe (102) and a circulating water outlet pipe (101).

5. The pipeline insulation and waste heat recovery device for a high-temperature fuel cell system according to claim 1, characterized in that: It also includes a heat-insulating box body (3), on which a heat-insulating box cover (6) is provided, and a heat-exchange recovery body composed of the high-temperature flue gas intake assembly (4), the circulating water heat exchange assembly (1) and the heat exchange cavity assembly (5) is placed in a sealed cavity composed of the heat-insulating box body (3) and the heat-insulating box cover (6).

6. The pipeline insulation and waste heat recovery device for a high-temperature fuel cell system according to claim 5, characterized in that: The heat-insulating box body (3) comprises a box body metal frame (301) and ceramic fiber insulation material boards arranged at the bottom and around the box body metal frame (301); the heat-insulating box cover (6) comprises a cover plate metal frame (601) and a top insulation board (602) arranged on the cover plate metal frame (601).

7. The pipeline insulation and waste heat recovery device for a high-temperature fuel cell system according to claim 2, characterized in that: The lower side of the heat exchange cavity shell (502) is provided with a small hole and is connected to a drainage pipeline for timely discharge of condensed water.

8. The pipeline insulation and waste heat recovery device for a high-temperature fuel cell system according to claim 3, characterized in that: The flue gas inlet pipe (402) is provided with an annular fin for increasing the flow path of the high-temperature flue gas, increasing the gas flow rate, and enhancing the heat exchange performance.

9. The pipeline insulation and waste heat recovery device for a high-temperature fuel cell system according to claim 4, characterized in that: The heat exchange spiral tube (103) is provided with an annular fin to increase the gas heat exchange area, guide the flow of high-temperature flue gas, and improve the flue gas waste heat recovery performance.

10. A pipeline insulation and waste heat recovery device for a high-temperature fuel cell system according to any one of claims 1-9, which is used in a high-temperature solid oxide fuel cell SOFC system, and the device is built inside the hot zone of the SOFC system, and its top is in contact with the inner wall of the SOFC hot zone insulation top plate.

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