Method and device for adjusting flow of circulating medium of circulating fluidized bed

Abstract

A circulating fluid bed circulating medium flow adjusting method and device relates to the field of solid waste and oil sludge pyrolysis treatment, and comprises a valve body, a circulation cavity is arranged in the valve body, the valve body is connected with an inlet pipeline, a pyrolysis pipeline and a bypass pipeline which are communicated with the circulation cavity, and the other ends of the inlet pipeline and the bypass pipeline are communicated with a circulating fluid bed hearth. The other end of the pyrolysis pipeline is communicated with pyrolysis equipment; the valve body is provided with a fluidization air device at the bottom of the circulation cavity; the valve body is provided with a pyrolysis path high-temperature gate valve at the connecting end of the circulating cavity and the pyrolysis pipeline, and is provided with a bypass path high-temperature gate valve at the connecting end of the circulating cavity and the bypass pipeline. The circulation of the solid particle circulating medium can be stably opened or closed, and the flow of the solid material circulating medium can be adjusted or automatically balanced, so that the characteristics and requirements of the operation working condition of the solid heat carrier furnace are met.

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste and oil sludge pyrolysis treatment, and relates to a circulating fluidized bed circulating medium flow regulating method and device. Background Art

[0002] Faced with the rapid growth and urgent treatment needs of solid waste and sludge in industry and life, the country has put forward the requirements of harmless, resource-based and reduced utilization. Pyrolysis treatment technology can realize advanced solid waste and sludge treatment processes, which can not only meet the national solid waste and sludge treatment requirements, but also effectively overcome the dioxin pollution problem caused by solid waste incineration. It has become an environmental protection treatment technology with great development prospects. As the main core equipment of solid waste and sludge treatment technology, the solid heat carrier furnace plays a major role in heating the solid heat carrier (circulating medium) in the pyrolysis unit, maintaining the circulation of the solid heat carrier, and sending the solid heat carrier into the pyrolysis system to provide a heat source for the pyrolysis material and ensure the implementation of the pyrolysis process.

[0003] The solid heat carrier furnace suitable for solid waste and sludge pyrolysis treatment technology adopts the form of fluidized bed boiler. The initial filling material in the furnace is a solid heat carrier within a certain particle size range. In addition to the solid heat carrier, the material returned to the furnace in the working state also includes the pyrolysis residue produced by the pyrolysis system. Since the pyrolysis system treats sludge and plastic materials, the pyrolysis residue contains a large amount of inorganic matter. As the system runs for a longer time, the composition of the circulating material will change from a single solid heat carrier to a mixture of solid heat carrier and ash, with the following characteristics: 1) There is no accurate calculation value for the amount of circulating material in the design, and it cannot be measured in actual operation. 2) The amount of circulating material is related to the ash content and varies greatly with the extension of the running time. 3) Under different loads, the circulation amount of solid heat carrier is different, which increases the difficulty of adjustment. 4) Due to the movement of solid particles, the parts working under high temperature, such as high-temperature gate valves, are severely worn.

[0004] In engineering applications, in order to meet the pyrolysis requirements, the circulating heat carrier flow entering the pyrolysis system of the solid heat carrier furnace must be quantitatively controlled. A single-loop U-type return valve or a U-type return valve that is only controlled by fluidizing air pneumatically cannot meet this regulation requirement. Summary of the invention

[0005] The technical problem solved by the present application is: to overcome the deficiencies of the prior art and to provide a circulating fluidized bed circulating medium flow rate regulation method and device, which can both stably open or close the circulation of solid particle circulating medium and regulate or automatically balance the solid material circulating medium flow rate, thereby adapting to the characteristics and requirements of the operating conditions of the solid heat carrier furnace.

[0006] A double-way U-shaped return valve is provided on the circulating fluidized bed. The flow of circulating medium in the two return legs of the circulating fluidized bed is adjusted by controlling the opening of two high-temperature plug valves on the two return legs under the return valve and combining the flow rates of two fluidizing air entering the return valve, so as to achieve quantitative control of the circulating medium entering the pyrolysis system, thereby providing a stable heat source for the pyrolysis system.

[0007] The technical solutions provided by this application are as follows:

[0008] A circulating medium flow regulating device for a circulating fluidized bed comprises a valve body, a flow cavity is arranged in the valve body, an inlet pipeline, a pyrolysis pipeline and a bypass pipeline which are connected to the flow cavity are connected to the valve body, the other ends of the inlet pipeline and the bypass pipeline are connected to the furnace of the circulating fluidized bed, the circulating medium in the furnace of the circulating fluidized bed enters the valve body through the inlet pipeline, the circulating medium in the valve body enters the furnace of the circulating fluidized bed through the bypass pipeline, and the other end of the pyrolysis pipeline is connected to the pyrolysis equipment;

[0009] The valve body is provided with a fluidizing air device at the bottom of the flow cavity, and the fluidizing air device is used to blow fluidizing air into the flow cavity so that the circulating medium flows into the pyrolysis pipeline and the bypass pipeline;

[0010] The valve body is provided with a pyrolysis circuit high-temperature gate valve at the connection end between the circulation cavity and the pyrolysis pipeline, and a bypass circuit high-temperature gate valve is provided at the connection end between the circulation cavity and the bypass pipeline. The pyrolysis circuit high-temperature gate valve is used to adjust the opening of the pyrolysis pipeline, and the bypass circuit high-temperature gate valve is used to adjust the opening of the bypass pipeline.

[0011] The circulation chamber includes a feed chamber, a loosening chamber, a bypass discharge chamber and a pyrolysis discharge chamber. The feed chamber is vertically arranged, the bottom of the feed chamber is connected to the middle of the loosening chamber, the two ends of the loosening chamber are respectively connected to one end of the bypass discharge chamber and the pyrolysis discharge chamber, and the other ends of the bypass discharge chamber and the pyrolysis discharge chamber are both upward and penetrate through the side wall of the valve body; the inlet pipeline is connected to the feed chamber, the bypass discharge chamber is connected to the bypass pipeline, and the pyrolysis discharge chamber is connected to the pyrolysis pipeline.

[0012] The pyrolysis circuit high temperature plug valve comprises a valve cover and a valve plate, the valve cover is connected with a connecting flange, the connecting flange is fixedly connected to the valve body, the valve body and the pyrolysis pipeline are provided with an insertion groove, and the valve plate is slidably connected to the valve cover and the insertion groove.

[0013] The valve plate is a square straight plate; the bypass high-temperature plug-in valve and the pyrolysis path high-temperature plug-in valve have the same structure.

[0014] The valve cover is provided with a plurality of purge holes, and nitrogen is blown into the valve cover through the purge holes.

[0015] The fluidizing air device comprises a plurality of bypass fluidizing air hoods, loosening air hoods and pyrolysis fluidizing air hoods arranged at the bottom of the flow cavity of the valve body, the loosening air hood is located between the bypass fluidizing air hood and the pyrolysis fluidizing air hood, the valve body is connected with a bypass inlet pipeline, a loosening air inlet pipeline and a pyrolysis inlet pipeline at the bottom of the loosening cavity, the bypass inlet pipeline, the loosening air inlet pipeline and the pyrolysis inlet pipeline are all connected with a fan, the bypass fluidizing air hood is connected with the bypass inlet pipeline, the pyrolysis fluidizing air hood is connected with the pyrolysis inlet pipeline, and the loosening air hood is connected with the loosening air inlet pipeline;

[0016] A bypass inlet branch pipeline is arranged on the bypass pipeline, and the bypass inlet branch pipeline is used for introducing air.

[0017] A plurality of pyrolysis path fluidizing hoods are arranged at the bottom of the inner surface of the pyrolysis pipeline, facing the position of the high-temperature gate valve of the pyrolysis path, and the pyrolysis path fluidizing hoods are connected to the pyrolysis inlet pipeline; a plurality of bypass path fluidizing hoods are arranged at the bottom of the inner surface of the bypass pipeline, facing the position of the high-temperature gate valve of the bypass path, and the bypass path fluidizing hoods are connected to the bypass inlet pipeline.

[0018] The inlet pipeline is connected to a plurality of purge air inlet pipelines; the bypass inlet pipeline, the loosening air inlet pipeline and the pyrolysis inlet pipeline are each connected to a purge air inlet pipeline.

[0019] A method for regulating the flow rate of circulating medium in a circulating fluidized bed, using any of the above-mentioned circulating fluidized bed circulating medium flow regulating devices for regulation, comprising:

[0020] S1: The final pyrolysis temperature of the pyrolysis device is used as a feedback signal to adjust the circulating medium flow of the pyrolysis pipeline and the bypass pipeline; when the difference between the final pyrolysis temperature and the target temperature is (-a, +a), a is set according to the pyrolysis operating conditions and is determined to be stable;

[0021] S2: The difference between the final pyrolysis temperature and the target temperature is lower or higher than (-a, +a), but the difference between the final pyrolysis temperature and the target temperature is within the range of (-b, +b), b is set according to the pyrolysis operating conditions, a<b, and the fluidizing air flow rate of the bypass inlet pipeline and the fluidizing air flow rate of the pyrolysis inlet pipeline are adjusted until the final pyrolysis temperature returns to the range of the target temperature ±a; if the final pyrolysis temperature still cannot return to the range of the target temperature ±a, adjust according to S3;

[0022] S3: The difference between the final pyrolysis temperature and the target temperature is lower or higher than (-b, +b), which is adjusted by the opening of the high-temperature gate valve in the bypass path and the opening of the high-temperature gate valve in the pyrolysis path.

[0023] The S2 includes:

[0024] If the difference between the final pyrolysis temperature and the target temperature is lower than or higher than (-a, +a), but the difference between the final pyrolysis temperature and the target temperature is within the range of (-b, +b), and the final pyrolysis temperature is lower than the target temperature -a, reduce the fluidizing air flow rate of the bypass inlet pipeline until the final pyrolysis temperature returns to within the range of the target temperature ±a, then stop adjusting; if the final pyrolysis temperature still cannot return to within the range of the target temperature ±a after the fluidizing air flow rate of the bypass inlet pipeline is reduced to the minimum value, then increase the fluidizing air flow rate of the pyrolysis inlet pipeline until the final pyrolysis temperature returns to within the range of the target temperature ±a, then stop adjusting; if the final pyrolysis temperature is higher than the target temperature +a, then adjust the fluidizing air flow rate of the bypass inlet pipeline and / or the pyrolysis inlet pipeline in the reverse direction;

[0025] S3 includes:

[0026] If the difference between the final pyrolysis temperature and the target temperature is lower than -b, increase the opening of the high-temperature plug valve of the pyrolysis path until the final pyrolysis temperature returns to the target temperature ±a, and then adjust according to S2; if the final pyrolysis temperature still cannot return to the target temperature ±a after the opening of the high-temperature plug valve of the pyrolysis path is increased to the maximum value, reduce the opening of the high-temperature plug valve of the bypass path until the final pyrolysis temperature returns to the target temperature ±a, and then adjust according to S2;

[0027] If the difference between the final pyrolysis temperature and the target temperature is higher than +b, the opening of the high-temperature gate valve of the pyrolysis path and / or the high-temperature gate valve of the bypass path is adjusted in reverse;

[0028] If the final pyrolysis temperature still cannot be restored to the target temperature ±a through the adjustment of the high-temperature gate valve in the pyrolysis path and the high-temperature gate valve in the bypass path, it is determined that the overall heat imbalance of the pyrolysis device is present and a prompt is given.

[0029] In summary, this application at least includes the following beneficial technical effects:

[0030] 1. The circulating fluidized bed fluidizing medium regulation scheme combining high-temperature gate valve and fluidizing air volume can significantly improve the regulation ratio of solid particle materials, improve the regulation accuracy of fluidizing medium, ensure that the pyrolysis system obtains more accurate solid heat carrier heat, thereby improving the accuracy of the pyrolysis final temperature of the pyrolysis system, and help improve the overall stability of the pyrolysis system and the quality of the oil generated by pyrolysis.

[0031] 2. The high-temperature plug-in valve cover is directly connected to the horizontal pipeline of the two-way U-type return valve in the form of a flange to replace the valve seat structure of the conventional plug-in valve, which greatly reduces the volume of the high-temperature plug-in valve and meets the installation requirements of the horizontal pipeline of the two-way U-type return valve, preventing the risk of the valve plate being unable to open or close normally due to a large amount of solid particles piling up on the valve plate if the high-temperature plug-in valve is installed on the inclined pipeline of the return valve. At the same time, the bottom of the high-temperature plug-in valve plate adopts a square straight plate form, and forms a hollow channel with the circular two-way U-type return valve pipeline, further avoiding the risk of solid particle circulation medium blocking the high-temperature plug-in valve plate.

[0032] 3. The integral valve plate of the high-temperature gate valve adopts a number of methods such as the selection of wear-resistant and temperature-resistant materials, hard alloy surfacing on the windward side, and surface spraying, which significantly improves the wear resistance and high temperature resistance of the high-temperature gate valve, so as to meet the requirements of the operating conditions of the solid heat carrier furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural diagram of a circulating medium flow regulating device for a circulating fluidized bed;

[0034] Figure 2 It is the structural diagram of the high-temperature gate valve of the bypass path and the high-temperature gate valve of the pyrolysis path.

[0035] Explanation of the accompanying figures: 1. Inlet pipeline; 2. Pyrolysis pipeline; 3. Bypass pipeline; 4. Bypass inlet pipeline; 5. Loosening air inlet pipeline; 6. Pyrolysis inlet pipeline; 7. Fluidizing air cap of bypass channel; 8. Loosening air cap; 9. Fluidizing air cap of pyrolysis channel; 10. High-temperature gate valve of bypass channel; 11. High-temperature gate valve of pyrolysis channel; 4-1. Fluidizing air cap of bypass channel; 6-1. Fluidizing air cap of pyrolysis channel; 13. Fluidizing air flow measurement point of bypass channel; 14. Loosening air flow measurement point; 15. Fluidizing air flow measurement point of pyrolysis channel; 16. Bypass inlet branch pipeline (air); 17. Purge air inlet; 18. Inspection hole; 19. Loosening chamber; 20. Pyrolysis chamber; 21. Bypass chamber;

[0036] 22. Connecting flange; 23. Valve plate; 25. Purge holes (distributed at multiple points along the circumference); 26. Valve cover. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0038] The present application embodiment discloses a circulating fluidized bed circulating medium flow regulating device, such as Figure 1 The figure shows a structural diagram of a circulating medium flow regulating device for a circulating fluidized bed.

[0039] A circulating fluidized bed circulating medium flow regulating device includes a valve body, a vertically arranged feed chamber is provided in the valve body, a horizontally arranged loosening chamber 19 is provided in the valve body, the bottom of the feed chamber is connected to the middle of the loosening chamber 19, a bypass discharge chamber and a pyrolysis discharge chamber are provided in the valve body, two ends of the loosening chamber are respectively connected to one end of the bypass discharge chamber and the pyrolysis discharge chamber, and the other ends of the bypass discharge chamber and the pyrolysis discharge chamber are both upward and penetrate the side wall of the valve body.

[0040] The inlet pipeline 1 is connected to the feed chamber of the valve body, and the circulating fluidized bed furnace is connected to the other end of the inlet pipeline 1; after the circulating medium is heated in the circulating fluidized bed furnace, it enters the feed chamber of the valve body through the inlet pipeline 1, and enters the loosening chamber 19 from the feed chamber. The pyrolysis pipeline 2 is connected to the end of the pyrolysis discharge chamber of the valve body, the bypass pipeline 3 is connected to the end of the bypass discharge chamber of the valve body, and the other end of the pyrolysis pipeline 2 is connected to the pyrolysis equipment. The space inside the pyrolysis pipeline 2 is the pyrolysis chamber 20, and the space inside the bypass pipeline 3 is the bypass chamber 21. Driven by the fluidizing wind, the circulating medium in the loosening chamber 19 is divided into two paths. First, the circulating medium enters the pyrolysis chamber 20 through the bypass discharge chamber, and enters the pyrolysis equipment from the pyrolysis chamber 20; the second circulating medium enters the bypass chamber 21 through the pyrolysis discharge chamber, and flows back to the circulating fluidized bed furnace from the bypass chamber 21.

[0041] The valve body is provided with a plurality of bypass fluidizing air hoods 7, loosening air hoods 8 and pyrolysis fluidizing air hoods 9 at the bottom of the loosening chamber 19. The loosening air hood 8 is located between the bypass fluidizing air hood 7 and the pyrolysis fluidizing air hood 9. The valve body is connected with a bypass inlet pipeline 4, a loosening air inlet pipeline 5 and a pyrolysis inlet pipeline 6 at the bottom of the loosening chamber 19. The bypass inlet pipeline 4, the loosening air inlet pipeline 5 and the pyrolysis inlet pipeline 6 are all connected with a fan. The bypass fluidizing air hood 7 is connected with the bypass inlet pipeline 4, so that the fluidizing air is blown from the bypass inlet pipeline 4. The fluidizing air hood 7 of the bypass path enters into the loosening chamber 19, and then blows the circulating medium from the bypass discharge chamber into the bypass pipeline 3; the fluidizing air hood 9 of the pyrolysis path is connected with the pyrolysis inlet pipeline 6, so that the fluidizing air enters into the loosening chamber 19 from the pyrolysis path fluidizing air hood 9, and then blows the circulating medium from the pyrolysis discharge chamber into the pyrolysis pipeline 2; the loosening air hood 8 is connected with the loosening air inlet pipeline 5, so that the fluidizing air enters into the loosening chamber 19 from the loosening air hood 8, so as to maintain the fluid state of the bed layer in the loosening chamber 19 and avoid particle aggregation and blockage.

[0042] The solid residue and pyrolysis gas generated in the pyrolysis equipment will flow back into the valve body along with the circulating medium.

[0043] The bypass discharge chamber and the pyrolysis discharge chamber both extend upward from the connection position with the loose chamber 19, and then have a very small horizontal extension section. The valve body is connected with a bypass high-temperature gate valve 10 and a pyrolysis high-temperature gate valve 11.

[0044] The bypass high temperature gate valve 10 and the pyrolysis high temperature gate valve 11 have the same structure. Figure 2 , which is a structural diagram of the bypass high temperature gate valve 10 and the pyrolysis path high temperature gate valve 11. The bypass high temperature gate valve 10 is taken as an example for structural description.

[0045] The bypass high temperature gate valve 10 comprises a valve cover 26 and a valve plate 23. The valve plate 23 is a square straight plate and is slidably connected to the valve cover 26. The valve cover 26 is connected with a connecting flange 22, which is used to connect the valve cover 26 and the valve body.

[0046] The valve body and the bypass pipeline 3 are provided with insertion grooves, and the valve plate 23 is inserted into the bypass pipeline 3 through the insertion grooves.

[0047] For the high-temperature plug valve 11 of the pyrolysis circuit, the pyrolysis pipeline 2 is also provided with an insertion groove, so that the valve plate 23 can be inserted into the pyrolysis pipeline 2 through the insertion groove.

[0048] The valve plate 23 opens or closes the bypass line 3 or the pyrolysis line 2 by sliding, and adjusts the circulating medium of the bypass line / pyrolysis line. The bottom of the valve plate 23 is in the form of a square straight plate, and forms a leakage channel with the circular pipes of the pyrolysis chamber 20 and the bypass chamber 21. The valve cover 26 is connected to the return valve through the connecting flange 22. The high-temperature plug valve valve cover 26 is arranged with purge holes 25 at multiple points along the circumferential direction. When the system is running, N2 is continuously supplied to purge the valve plate to further prevent the high-temperature plug valve from getting stuck.

[0049] The circulating medium enters the loosening chamber 19 from the inlet pipe 1, and then the circulating medium is divided into two paths: one path enters the pyrolysis pipe 2 through the pyrolysis chamber 20 to provide heat for the pyrolysis system, and the mixture of the circulating medium and the pyrolysis residue that is cooled to the stable pyrolysis final temperature after the reaction returns to the circulating fluidized bed furnace; the other path enters the bypass pipe 3 through the bypass chamber 21, and the excess high-temperature circulating medium is directly returned to the circulating fluidized bed furnace. The two high-pressure fluidizing winds enter the pyrolysis chamber 20 and the bypass chamber 21 from the bypass fluidizing wind cap 7 and the pyrolysis fluidizing wind cap 9, respectively, so that the circulating medium is fluidized and enters the pyrolysis pipe 2 and the bypass pipe 3. One high-pressure loosening wind enters the loosening chamber 19 from the loosening wind inlet pipe 5 through the loosening wind cap 8 to maintain the flow state of the bed layer in the return valve to avoid particle aggregation and blockage. The two high-pressure fluidizing winds and one high-pressure loosening wind are supplied by the air distribution chamber.

[0050] The pyrolysis chamber 20 and the bypass chamber 21 are respectively provided with a bypass channel high temperature gate valve 10 and a pyrolysis channel high temperature gate valve 11. The flow of the two circulating media is adjusted by the valve plate opening to achieve a rough adjustment of the final temperature of the pyrolysis. The other two high pressure fluidizing airs enter the pyrolysis chamber 20 from the bypass inlet pipeline 4 and the pyrolysis inlet pipeline 6 through the pyrolysis channel high temperature gate valve fluidizing air cap 12. The air cap points to the bypass channel high temperature gate valve 10 and the pyrolysis channel high temperature gate valve 11 to strengthen the fluidization of the medium around the valve plate to prevent blockage. The bypass inlet pipeline 4, the loosening air inlet pipeline 5, and the pyrolysis inlet pipeline 6 are provided with a bypass channel fluidizing air flow measurement point 13, a loosening air flow measurement point 14, and a pyrolysis channel fluidizing air flow measurement point 15. The flow of the two circulating media is adjusted by the flow of the two fluidizing airs to achieve a fine adjustment of the final temperature of the pyrolysis. In order to maintain an anaerobic environment of the pyrolysis system, N2 is used for the fluidizing air and loosening air entering from the bypass inlet pipeline 4, the loosening air inlet pipeline 5, and the pyrolysis inlet pipeline 6. A bypass inlet branch pipeline 16 is provided on the bypass chamber 21, and the bypass inlet branch pipeline 16 is used to introduce air. When the pyrolysis system is running stably, high-pressure air can be introduced from here to replace the N2 introduced from the bypass inlet pipeline 4 to achieve fluidization.

[0051] In order to further prevent the circulation medium from being blocked, a plurality of purge air inlet passages 17 are provided on the loosening chamber 19, and high-pressure air (when the furnace is shut down for maintenance) or N2 (when the pyrolysis system is running) is blown into the loosening chamber 19 to achieve regular or fault purge. Specifically, a plurality of purge air inlet passages 17 are connected to the inlet pipeline 1 to avoid; the bypass inlet pipeline 4, the loosening air inlet pipeline 5 and the pyrolysis inlet pipeline 6 are each connected to the purge air inlet passage 17. The pyrolysis chamber 20 and the bypass chamber 21 are provided with inspection holes 18 for troubleshooting and shutdown maintenance.

[0052] Rely on Figure 1A circulating fluidized bed circulating medium flow regulating device, this patent proposes a circulating fluidized bed circulating medium flow regulating method. The purpose is to achieve quantitative control of the circulating medium entering the pyrolysis system by adjusting the circulating medium flow ratio in the pyrolysis pipeline 2 and the bypass pipeline 3 in the circulating fluidized bed, so as to provide a stable heat source for the pyrolysis system. The stability of the heat source of the pyrolysis system is determined by selecting the pyrolysis final temperature as a feedback signal: (1) The pyrolysis final temperature is stable within a small range of values, that is, it is determined to be stable and no adjustment means are required. In an engineering case, the range value is 450±10℃. (2) When the pyrolysis final temperature exceeds the range value described in (1), but the pyrolysis final temperature has not reached a violent fluctuation, it is determined that the pyrolysis final temperature needs to be fine-tuned, and it is adjusted by the pyrolysis path fluidizing air flow and the bypass path fluidizing air flow (that is, the gas flow in the bypass inlet pipeline 4 and the pyrolysis inlet pipeline 6). In an engineering case, the violent fluctuation temperature range is 450±50℃. (3) When the final pyrolysis temperature exceeds the range value described in (2), it is determined that the final pyrolysis temperature needs to be roughly adjusted, and it is adjusted by the opening of the high-temperature gate valve 11 of the pyrolysis path and the opening of the high-temperature gate valve 10 of the bypass path.

[0053] In the above case (2), if the final pyrolysis temperature is lower than the lower value in the range of values ​​described in (1), first reduce the bypass fluidizing air flow rate by means of the fan opening or frequency, so that more circulating medium enters the pyrolysis pipeline 2, until the final pyrolysis temperature returns to the stable value range of (1), then stop adjusting; or if the bypass fluidizing air flow rate is reduced to the minimum value and the final pyrolysis temperature still cannot return to the stable value range of (1), then increase the pyrolysis fluidizing air flow rate by means of the fan opening or frequency, until the final pyrolysis temperature returns to the stable value range of (1), then stop adjusting. If the final pyrolysis temperature is higher than the higher value in the range of values ​​described in (1), then adjust the fan opening or frequency in the opposite direction according to the above order. In the above case (2), if all adjustment means have been exhausted and the final pyrolysis temperature still cannot return to the stable value range of (1), then operate according to the following case (3).

[0054] In the above case (3), if the final pyrolysis temperature is lower than the lower value in the range of values ​​described in (2), first increase the opening of the high-temperature plug valve of the pyrolysis path until the final pyrolysis temperature returns to the temperature range of (2), and then adjust it by the above operation method (2). Alternatively, if the final pyrolysis temperature still cannot be restored to the stable value range (2) after the opening of the high-temperature plug valve of the pyrolysis path is increased to the maximum value, then reduce the opening of the high-temperature plug valve of the bypass path until the final pyrolysis temperature returns to the stable value range (2), and then adjust it by the above operation method (2). If the final pyrolysis temperature is higher than the higher value in the range of values ​​described in (2), adjust the opening of the high-temperature plug valve in the opposite direction according to the above order. In the above case (3), if all adjustment means have been exhausted and the final pyrolysis temperature still cannot be restored to the stable value range (2), it is determined that the overall heat imbalance of the pyrolysis system is present, and a prompt is given. In one engineering case, the prompt is to reduce / increase the feed amount of the pyrolysis system.

[0055] In summary: This patent provides a circulating fluidized bed circulating medium flow regulating device:

[0056] 1. A dual-path U-shaped return valve structure is used to divide the circulating medium of the circulating fluidized bed into two paths: one path enters the pyrolysis system to provide heat for the pyrolysis system, and the mixture of the circulating medium and the pyrolysis residue that has been cooled to a stable pyrolysis final temperature after the reaction returns to the furnace of the circulating fluidized bed; the other path enters the bypass path to directly return the excess high-temperature circulating medium to the furnace of the circulating fluidized bed. A high-temperature plug valve is set on the pyrolysis path and the bypass path of the dual-path U-shaped return valve, and the flow of the two-path circulating medium can be adjusted by the valve plate opening. At the same time, two high-pressure fluidizing air and one high-pressure loosening air are sent in from the bottom air chamber of the dual-path U-shaped return valve, and the flow of the two-path circulating medium can also be adjusted by the air flow. The three-path air is supplied by the split air chamber.

[0057] 2. If the high-temperature gate valve is installed on the inclined pipe of the return valve, a large amount of solid particles are easily accumulated on the valve plate, and the valve plate cannot be opened or closed normally due to clogging. In order to realize the circulating medium regulation function and reduce the occurrence of valve plate clogging, the high-temperature gate valve is required to be installed on the horizontal pipe of the two-way U-type return valve. Since the circulating medium is not easy to flow in the horizontal pipe section, the return valve is required to be as short as possible when designing the horizontal pipe. Subject to this, the structure of directly connecting the high-temperature gate valve cover to the horizontal pipe of the two-way U-type return valve in the form of a flange is adopted to replace the valve seat structure of the conventional gate valve, so as to reduce the volume of the high-temperature gate valve so that it can meet the requirements of being installed in the horizontal pipe of the two-way U-type return valve.

[0058] 3. Due to the movement of solid particles in the circulating medium, the valve plate working under high temperature is also seriously worn. Therefore, the overall valve plate of the high-temperature plug valve of this patent adopts a number of methods such as selecting wear-resistant and temperature-resistant materials, surfacing hard alloy on the windward side, and surface spraying to improve the wear-resistant and high-temperature resistant characteristics of the high-temperature plug valve, so as to meet the requirements of the operating conditions of the solid heat carrier furnace.

[0059] 4. The bottom of the high-temperature plug-in valve plate adopts a square straight plate form, and forms a hollow channel with the circular double-way U-shaped return valve pipeline to prevent the circulating medium from blocking the high-temperature plug-in valve plate. At the same time, the high-temperature plug-in valve cover is arranged with purge holes at multiple points along the circumferential direction. When the system is running, N2 is continuously sent to purge the valve plate to further prevent the high-temperature plug-in valve from being blocked.

[0060] 5. To maintain an anaerobic environment for the pyrolysis system, N2 is used for the fluidizing air, loosening air, and purge air in the dual-way U-type return valve. A high-pressure air inlet is set on the bypass fluidizing air duct. When the pyrolysis system is running stably, high-pressure air can be introduced from this inlet to replace N2 to achieve fluidization.

[0061] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0062] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A circulating medium flow regulating device for a circulating fluidized bed, characterized in that: The invention comprises a valve body, wherein a circulation cavity is arranged in the valve body, and the valve body is connected to an inlet pipeline (1), a pyrolysis pipeline (2) and a bypass pipeline (3) which are in communication with the circulation cavity, the other ends of the inlet pipeline (1) and the bypass pipeline (3) are in communication with a circulating fluidized bed furnace, the circulating medium in the circulating fluidized bed furnace enters the valve body through the inlet pipeline (1), the circulating medium in the valve body enters the circulating fluidized bed furnace through the bypass pipeline (3), and the other end of the pyrolysis pipeline (2) is in communication with a pyrolysis device; The valve body is provided with a fluidizing air device at the bottom of the flow chamber, and the fluidizing air device is used to blow fluidizing air into the flow chamber so that the circulating medium flows into the pyrolysis pipeline (2) and the bypass pipeline (3); The valve body is provided with a pyrolysis path high temperature gate valve (11) at the connection end between the circulation chamber and the pyrolysis pipeline (2), and a bypass path high temperature gate valve (10) at the connection end between the circulation chamber and the bypass pipeline (3). The pyrolysis path high temperature gate valve (11) is used to adjust the opening of the pyrolysis pipeline (2), and the bypass path high temperature gate valve (10) is used to adjust the opening of the bypass pipeline (3).

2. The circulating medium flow regulating device for a circulating fluidized bed according to claim 1, characterized in that: The circulation chamber comprises a feed chamber, a loosening chamber (19), a bypass discharge chamber and a pyrolysis discharge chamber. The feed chamber is vertically arranged, the bottom of the feed chamber is connected to the middle of the loosening chamber (19), the two ends of the loosening chamber are respectively connected to one end of the bypass discharge chamber and the pyrolysis discharge chamber, and the other ends of the bypass discharge chamber and the pyrolysis discharge chamber are both upward and penetrate the side wall of the valve body; the inlet pipeline (1) is connected to the feed chamber, the bypass discharge chamber is connected to the bypass pipeline (3), and the pyrolysis discharge chamber is connected to the pyrolysis pipeline (2).

3. The circulating medium flow regulating device for a circulating fluidized bed according to claim 1, characterized in that: The pyrolysis circuit high-temperature plug-in valve (11) comprises a valve cover (26) and a valve plate (23); the valve cover (26) is connected to a connecting flange (22); the connecting flange (22) is fixedly connected to a valve body; an insertion groove is provided in the valve body and the pyrolysis pipeline (2); and the valve plate (23) is slidably connected to the valve cover (26) and the insertion groove.

4. The circulating medium flow regulating device for a circulating fluidized bed according to claim 3, characterized in that: The valve plate (23) is a square straight plate; the bypass high-temperature plug-in valve (10) and the pyrolysis path high-temperature plug-in valve (11) have the same structure.

5. The circulating medium flow regulating device for a circulating fluidized bed according to claim 3, characterized in that: The valve cover (26) is provided with a plurality of purge holes (25), and nitrogen is blown into the valve cover (26) through the purge holes (25).

6. A circulating medium flow regulating device for a circulating fluidized bed according to claim 1 or 3, characterized in that: The fluidizing air device comprises a plurality of bypass fluidizing air hoods (7), loosening air hoods (8) and pyrolysis path fluidizing air hoods (9) arranged at the bottom of the flow cavity of the valve body; the loosening air hood (8) is located between the bypass fluidizing air hood (7) and the pyrolysis path fluidizing air hood (9); the valve body is connected to a bypass inlet pipeline (4), a loosening air inlet pipeline (5) and a pyrolysis inlet pipeline (6) at the bottom of the loosening cavity (19); the bypass inlet pipeline (4), the loosening air inlet pipeline (5) and the pyrolysis inlet pipeline (6) are all connected to a fan; the bypass fluidizing air hood (7) is connected to the bypass inlet pipeline (4); the pyrolysis path fluidizing air hood (9) is connected to the pyrolysis inlet pipeline (6); and the loosening air hood (8) is connected to the loosening air inlet pipeline (5); A bypass inlet branch pipeline (16) is provided on the bypass pipeline (3), and the bypass inlet branch pipeline (16) is used to introduce air.

7. The circulating medium flow regulating device for a circulating fluidized bed according to claim 6, characterized in that: A plurality of pyrolysis path fluidizing hoods (6-1) are arranged at the bottom of the inner surface of the pyrolysis path, facing the position of the pyrolysis path high-temperature gate valve (11), and the pyrolysis path fluidizing hoods (6-1) are connected to the pyrolysis inlet path (6); a plurality of bypass path fluidizing hoods (4-1) are arranged at the bottom of the inner surface of the bypass path, facing the position of the bypass path high-temperature gate valve (10), and the bypass path fluidizing hoods (4-1) are connected to the bypass inlet path (4).

8. The circulating medium flow regulating device for a circulating fluidized bed according to claim 1, characterized in that: The inlet pipeline (1) is connected to a plurality of purge air inlet pipelines (17); the bypass inlet pipeline (4), the loosening air inlet pipeline (5) and the pyrolysis inlet pipeline (6) are each connected to a purge air inlet pipeline (17).

9. A method for regulating the flow rate of circulating medium in a circulating fluidized bed, characterized in that: The circulating medium flow rate regulating device of a circulating fluidized bed according to any one of claims 1 to 9 is used for regulation, comprising: S1: The final pyrolysis temperature of the pyrolysis device is used as a feedback signal to adjust the circulating medium flow of the pyrolysis pipeline (2) and the bypass pipeline (3); when the difference between the final pyrolysis temperature and the target temperature is (-a, +a), a is set according to the pyrolysis operating conditions and is determined to be stable; S2: The difference between the final pyrolysis temperature and the target temperature is lower or higher than (-a, +a), but the difference between the final pyrolysis temperature and the target temperature is within the range of (-b, +b), b is set according to the pyrolysis operating conditions, a<b, and the fluidizing air flow rate of the bypass inlet pipeline (4) and the fluidizing air flow rate of the pyrolysis inlet pipeline (6) are adjusted until the final pyrolysis temperature returns to the range of the target temperature ±a; if the final pyrolysis temperature still cannot return to the range of the target temperature ±a, then adjust according to S3; S3: The difference between the final pyrolysis temperature and the target temperature is lower or higher than (-b, +b), which is adjusted by the opening of the bypass high-temperature gate valve (10) and the opening of the pyrolysis path high-temperature gate valve (11).

10. A method for regulating the flow rate of circulating medium in a circulating fluidized bed according to claim 9, characterized in that: The S2 includes: If the difference between the final pyrolysis temperature and the target temperature is lower than or higher than (-a, +a), but the difference between the final pyrolysis temperature and the target temperature is within the range of (-b, +b), and the final pyrolysis temperature is lower than the target temperature -a, the fluidizing air flow rate of the bypass inlet pipeline (4) is reduced until the final pyrolysis temperature returns to within the range of the target temperature ±a, then the adjustment is stopped; if the final pyrolysis temperature still cannot return to within the range of the target temperature ±a after the fluidizing air flow rate of the bypass inlet pipeline (4) is reduced to the minimum value, then the fluidizing air flow rate of the pyrolysis inlet pipeline (6) is increased until the final pyrolysis temperature returns to within the range of the target temperature ±a, then the adjustment is stopped; if the final pyrolysis temperature is higher than the target temperature +a, then the fluidizing air flow rate of the bypass inlet pipeline (4) and / or the pyrolysis inlet pipeline (6) is adjusted in the reverse direction; S3 includes: If the difference between the final pyrolysis temperature and the target temperature is lower than -b, the opening of the high-temperature plug valve (11) of the pyrolysis path is increased until the final pyrolysis temperature returns to the target temperature ±a, and then the adjustment is performed according to S2; if the final pyrolysis temperature still cannot return to the target temperature ±a after the opening of the high-temperature plug valve (11) of the pyrolysis path is increased to the maximum value, the opening of the high-temperature plug valve (10) of the bypass path is reduced until the final pyrolysis temperature returns to the target temperature ±a, and then the adjustment is performed according to S2; If the difference between the final pyrolysis temperature and the target temperature is greater than +b, the opening of the pyrolysis path high temperature gate valve (11) and / or the bypass path high temperature gate valve (10) is reversely adjusted; If the pyrolysis final temperature still cannot be restored to the target temperature ±a through the adjustment of the pyrolysis path high temperature gate valve (11) and the bypass path high temperature gate valve (10), it is determined that the overall heat imbalance of the pyrolysis device is present and a prompt is given.

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