Flue accumulated dust cleaning device of circulating fluidized bed separator

Abstract

The invention relates to a circulating fluidized bed separator flue accumulated dust cleaning device which comprises a purging distribution box, the input end of the purging distribution box is connected with a hot primary air pipe, a hot secondary air pipe and a high-pressure fluidization air pipe, and the output end of the purging distribution box is connected with an air supply pipe; the air supply pipe is connected with a plurality of hoses, the tail ends of the hoses are provided with fluidization-shaped air caps, and each fluidization-shaped air cap is provided with at least one horizontally-arranged guide pipe and at least two symmetrically-arranged air guide pipes which are obliquely arranged downwards; a plurality of groups of fluidization-shaped air caps are mounted in the separator inlet flue and are uniformly distributed along the flow direction of flue gas; according to the method, accumulated dust in the inlet flue of the cyclone separator can be effectively removed on line in the unit operation period (without boiler shutdown), and it is guaranteed that the efficiency of the circulating fluidized bed boiler separator meets the requirements for unit safe operation and large load. Various air pressure and air volume choices are provided, when a certain air source breaks down or the pressure is insufficient, other air sources can be immediately switched or used in a combined mode, and it is guaranteed that dust removal power is continuous and reliable.

Description

Technical Field

[0001] This invention relates to the field of thermal power generation technology, specifically to a device for cleaning ash deposits in the flue gas duct of a circulating fluidized bed separator. Background Technology

[0002] During the hot operation of a circulating fluidized bed boiler, when the unit load and coal quality change, the concentration of circulating materials inside and outside the furnace; the flue gas pressure in the separator inlet and outlet flues; the temperature of the separator flue and its interior; and the internal pressure and temperature of the return valve will also change by orders of magnitude. This will cause ash to accumulate in the separator inlet flue, disrupting the flue gas velocity at the inlet of the circulating fluidized bed boiler separator, affecting the separation efficiency of the circulating fluidized bed boiler separator, and further affecting the safe operation of the unit and its ability to handle large loads.

[0003] In the prior art, in order to prevent ash accumulation in the flue gas at the separator inlet, air blowing is usually used to continuously blow away the ash. After blowing, the floating ash particles will be carried into the separator by the flue gas, thereby preventing ash accumulation. For example, the "Device for Preventing Ash Accumulation in the Horizontal Flue of a Separator" disclosed in patent number CN205026656. However, existing technologies employ a "continuous purging" method, which is a constant output mode that does not consider the actual operating conditions of the boiler. Furthermore, the purging power source is singular and uncontrollable, making it unable to cope with complex changes in operating conditions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a circulating fluidized bed separator flue gas ash cleaning device to solve the aforementioned problems.

[0005] This invention provides the following technical solution: A circulating fluidized bed separator flue gas ash cleaning device includes: The purge distribution box has a hot primary air duct, a hot secondary air duct, and a high-pressure fluidizing air duct connected to its input end, and an air supply duct connected to its output end. The primary hot air duct, the secondary hot air duct, and the high-pressure fluidized air duct are each equipped with a corresponding electric damper. A flow meter and a pressure transmitter are installed on the air supply pipe; The air supply pipe is connected to multiple flexible hoses, and the ends of the flexible hoses are provided with fluidizing air caps. The fluidizing air caps have at least one horizontally arranged guide pipe and at least two symmetrically arranged downward inclined air guide pipes. Multiple sets of fluidizing caps are installed inside the separator inlet flue and are evenly distributed along the flue gas flow direction.

[0006] Preferably, the primary hot air duct, the secondary hot air duct, and the high-pressure fluidizing air duct are connected to the primary hot air fan, the secondary hot air fan, and the high-pressure fluidizing air fan, respectively.

[0007] Preferably, the primary hot air duct, secondary hot air duct, high-pressure fluidized air duct, and air supply duct are all made of carbon steel with metal expansion devices.

[0008] Preferably, the fluidized bed wind cap is made of high-temperature heat-resistant alloy steel of model SA351-HK40.

[0009] Preferably, the top of the fluidized head is covered with a silicon carbide corundum wear-resistant plastic layer.

[0010] Preferably, the fluidized head is equipped with a manual ball valve and a check valve.

[0011] Preferably, the ash removal device can manually switch the air source according to the actual combustion conditions of the boiler, or automatically switch the air source through an electric damper based on changes in air volume and air pressure via DCS logic.

[0012] Preferably, the orientation of the air duct and the guide pipe is consistent with the corresponding flue gas flow direction; the air duct is located on the side of the guide pipe near the bottom wall of the separator inlet flue.

[0013] The present invention has the following beneficial technical effects: This invention can effectively remove ash accumulation inside the inlet flue of the cyclone separator online during unit operation (without shut-off), ensuring that the efficiency of the circulating fluidized bed boiler separator meets the requirements for safe unit operation and high load.

[0014] By designing hot primary air ducts, hot secondary air ducts, and high-pressure fluidized air ducts, the traditional single air source mode has been changed, providing a variety of air pressure and air volume options. When a certain air source fails or the pressure is insufficient, other air sources can be switched or combined immediately, ensuring continuous and reliable dust removal power.

[0015] A closed-loop control system is formed by electric dampers, flow meters, and pressure transmitters. The system can automatically adjust the air source, airflow, and pressure of the purging air based on real-time unit load, coal quality changes, and pressure signals at the separator inlet and outlet, achieving "on-demand purging" rather than "continuous purging." This ensures effective dust removal while avoiding excessive interference with the separator inlet flow field caused by constant purging in the past, thus optimizing separation efficiency.

[0016] The high-speed airflow generated by the horizontally set guide pipe mainly acts to impact and sweep away the ash deposited in the "dead zone" at the bottom or wall of the flue, thus playing a direct role in ash removal.

[0017] The airflow generated by the symmetrically inclined downward-sloping air ducts acts on the area below the swept-up ash particles, forming an air cushion or fluidized layer. This keeps the ash particles in a suspended state, making them easier to be carried away by the main flue gas and preventing them from settling again. This combination of "sweeping + fluidization" greatly improves the efficiency and thoroughness of dust removal.

[0018] The symmetrical design of the air duct can balance the forces of airflow, avoid excessive lateral disturbance of the main flue gas flow field by airflow on one side, and protect the inlet condition of the separator. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the fluidized head structure of the present invention; Figure 3 This is a schematic diagram of the fluidized air cap arrangement of the present invention in the separator inlet flue.

[0020] The attached figures are labeled as follows: 1. Purge distribution box; 2. Hot primary air duct; 3. Hot secondary air duct; 4. High-pressure fluidized air duct; 5. Electric damper; 6. Air supply duct; 61. Flow meter; 62. Pressure transmitter; 7. Hose; 8. Fluidized air cap; 81. Silicon carbide corundum wear-resistant plastic layer; 82. Check valve; 83. Air guide duct; 84. Guide tube. Detailed Implementation

[0021] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example: Circulating fluidized bed separator flue gas ash cleaning device, refer to Figures 1-3 : A φ186mm carbon steel pipe with a wall thickness of 6mm is used as the purging distribution box 1. Three φ156mm carbon steel pipes with a wall thickness of 6mm are introduced into the purging distribution box 1 as the hot primary air pipe 2, hot secondary air pipe 3, and high-pressure fluidizing air pipe 4, respectively. The hot primary air pipe 2 is connected to the on-site hot primary air fan, the hot secondary air pipe 3 is connected to the on-site hot secondary air fan, and the high-pressure fluidizing air pipe 4 is connected to the on-site high-pressure fluidizing fan. Metal expansion devices are reasonably installed in the hot primary air pipe 2, hot secondary air pipe 3, and high-pressure fluidizing air pipe 4 according to their length and expansion direction. Three air sources are designed to take into account the system air pressure requirements under different combustion conditions of the boiler. One-to-one electric dampers 5 are installed on the primary hot air duct 2, the secondary hot air duct 3, and the high-pressure fluidized air duct 4 as system isolation and air source switching devices.

[0023] A φ108mm carbon steel pipe with a wall thickness of 6mm is led out from the purge distribution box 1 as the air supply pipe 6. The air supply pipe 6 is equipped with a metal expansion device according to its length and expansion direction. The air supply pipe 6 is led to a fixed position 1 meter below the inlet flue of the separator. The top of the air supply pipe 6 is sealed and closed. A flow meter 61 and a pressure transmitter 62 are installed in the air supply pipe 6 as DCS monitoring parameters and analog quantities for automatic air source switching logic judgment.

[0024] Four sets of φ76 circular holes are opened at an elevation of 100mm-150mm below the top of the air supply duct 6. Four sets of circular stainless steel flanges are welded to the holes. Four flexible hoses 7 (stainless steel) with a length of 1200mm and φ76 are matched. One end of the four flexible hoses 7 is bolted to the four sets of stainless steel flanges. The other end of the flexible hoses 7 is equipped with a fluidizing air cap 8.

[0025] Four sets of φ70 round holes are opened on the bottom plate fins of the separator flue along the flue gas flow direction to allow the flexible hose 7 to pass through, so that the fluidized air cap 8 is placed inside the separator flue. In this embodiment, four flue gas flow paths are selected, and four sets of fluidized air caps 8 are relatively evenly arranged on each flue gas flow path.

[0026] The fluidized air cap 8 is made of high-temperature heat-resistant alloy steel of model SA351-HK40. The top of the fluidized air cap 8 is covered with a silicon carbide corundum wear-resistant plastic layer 81 as an anti-wear device. The four sets of fluidized air caps 8 corresponding to the same air supply pipe 6 are arranged on different flue gas flow paths. A manual ball valve (stainless steel) is installed on the fluidizing vent cap 8 or the hose 7. A flap-type check valve 82 is installed inside the fluidizing vent cap 8 to prevent hot ash from flowing back into the hose 7 when the air supply device stops operating.

[0027] A guide pipe 84 is horizontally installed on the fluidized air cap 8, and the orientation of the guide pipe 84 is consistent with the corresponding flue gas flow path. The high-speed airflow generated on the guide pipe 84 mainly acts to impact and sweep the ash deposited in the "dead zone" at the bottom or wall of the flue, thus playing a direct ash removal role.

[0028] The fluidized bed hood 8 is symmetrically equipped with two sets of air guide pipes 83. The air guide pipes 83 are located below the guide pipe 84 (closer to the inner wall of the separator inlet flue), and the air guide pipes 8 are inclined downwards (aligning with the corresponding flue gas flow path in terms of horizontal force). The airflow generated by the air guide pipes 83 acts on the area below the swept-up ash particles, forming an air cushion or fluidized layer, keeping the ash particles in a suspended state, making them easy to be carried away by the main flue gas and preventing them from settling again. This combination of "sweeping + fluidization" greatly improves the efficiency and thoroughness of dust removal.

[0029] The symmetrical design of the air duct can balance the forces of airflow, avoid excessive lateral disturbance of the main flue gas flow field by airflow on one side, and protect the inlet condition of the separator.

[0030] This device can manually switch the air source according to the actual combustion conditions of the boiler, or the DCS logic can automatically switch the air source through the electric damper 5 according to changes in air volume and air pressure.

[0031] Multiple fluidized bed air caps 8 are arranged inside the separator inlet flue, achieving intervention at the source. Multiple fluidized bed air caps 8 are evenly distributed in each flue gas flow direction, ensuring that there are no blind spots in the entire flue cross-section and achieving a comprehensive, synchronous cleaning effect. This arrangement allows the airflow generated by each fluidized bed air cap 8 to coordinate with the main flue gas flow, smoothly "pushing" the accumulated ash to the separator, rather than creating localized eddies that lead to secondary ash accumulation.

[0032] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A flue gas ash cleaning device for a circulating fluidized bed separator, characterized in that, include: The purge distribution box (1) has a hot primary air pipe (2), a hot secondary air pipe (3) and a high-pressure fluidizing air pipe (4) connected to its input end, and an air supply pipe (6) connected to its output end. The primary hot air duct (2), the secondary hot air duct (3), and the high-pressure fluidized air duct (4) are each equipped with a corresponding electric damper (5); A flow meter (61) and a pressure transmitter (62) are installed on the air supply pipe (6). Multiple hoses (7) are connected to the air supply pipe (6). A fluidized air cap (8) is provided at the end of the hose (7). The fluidized air cap (8) has at least one horizontally arranged guide pipe (84) and at least two symmetrically arranged downward inclined air guide pipes (83). Multiple sets of fluidized air caps (8) are installed inside the separator inlet flue and are evenly distributed along the flue gas flow direction.

2. The circulating fluidized bed separator flue gas ash cleaning device according to claim 1, characterized in that, The primary hot air duct (2), the secondary hot air duct (3), and the high-pressure fluidizing air duct (4) are respectively connected to the primary hot air fan, the secondary hot air fan, and the high-pressure fluidizing air fan.

3. The circulating fluidized bed separator flue gas ash cleaning device according to claim 1, characterized in that, The primary hot air duct (2), secondary hot air duct (3), high-pressure fluidized air duct (4), and air supply duct (6) are all made of carbon steel with metal expansion devices.

4. The circulating fluidized bed separator flue gas ash cleaning device according to claim 1, characterized in that, The fluidized wind cap (8) is made of high-temperature heat-resistant alloy steel with model number SA351-HK40.

5. The circulating fluidized bed separator flue gas ash cleaning device according to claim 1, characterized in that, The top of the fluidized wind cap (8) is covered with a silicon carbide corundum wear-resistant plastic layer (81).

6. The circulating fluidized bed separator flue gas ash cleaning device according to claim 1, characterized in that, The fluidized air cap (8) is equipped with a manual ball valve and a check valve (82).

7. The circulating fluidized bed separator flue gas ash cleaning device according to claim 1, characterized in that, The ash removal device can manually switch the air source according to the actual combustion conditions of the boiler, or automatically switch the air source through the electric damper (5) according to the changes in air volume and air pressure through DCS logic.

8. The circulating fluidized bed separator flue gas ash cleaning device according to claim 1, characterized in that, The orientation of the air duct (83) and the guide pipe (84) is consistent with the corresponding flue gas flow direction; the air duct (83) is located on the side of the guide pipe (84) near the bottom wall of the separator inlet flue.

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