A circulating ash load regulating device and method for a circulating fluidized bed boiler

Abstract

A circulating ash load regulating device and method for a circulating fluidized bed boiler belongs to the technical field of circulating fluidized bed boilers. This invention solves the problem that existing circulating fluidized bed boilers cannot meet the requirement of rapid load changes during rapid load increases and decreases. One end of the ash inlet pipe is connected and fixedly connected to the return material device, and the other end is inserted into the ash storage silo. A first manual shut-off valve and a first electric shut-off valve are sequentially installed on the ash inlet pipe. One end of the ash outlet pipe is connected and fixedly connected to the bottom of the ash storage silo, and the other end is connected and fixedly connected to the inlet of the ash conveying main pipe. Each ash conveying main pipe outlet is connected and fixedly connected to a corresponding ash conveying branch pipe. A second manual shut-off valve, a second electric shut-off valve, and an electric rotary ash feeding valve are sequentially installed on the ash outlet pipe from top to bottom. This invention can effectively store ash in the furnace into the ash storage silo through the feeding device, and can promptly add ash from the ash storage silo back into the furnace through the discharging device, achieving rapid increases and decreases in boiler load.

Description

Technical Field

[0001] This invention relates to a circulating ash load regulating device and method for a circulating fluidized bed boiler, belonging to the technical field of circulating fluidized bed boilers. Background Technology

[0002] Circulating fluidized bed (CFB) boilers are widely used due to their wide fuel adaptability, ability to burn low-quality fuels, stable and efficient combustion, superior environmental performance, and good load regulation characteristics. Many industrial plants use CFB boilers as their own power stations, and the load of CFB units needs to be flexibly adjusted according to the plant's electricity and steam consumption. Because CFB boilers contain a large amount of wear-resistant refractory castable and a large amount of circulating material, they have a large heat storage capacity but a slow heat storage and release rate. When the boiler needs to operate under varying loads, relying solely on its own heat capacity, the response of load and parameters is relatively slow, and it cannot quickly keep up with the requirements of changing operating conditions, resulting in a problem of not being able to meet the requirements for rapid load changes. Summary of the Invention

[0003] The present invention aims to solve the above-mentioned problems and provides a circulating ash load regulating device and regulating method for circulating fluidized bed boilers.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0005] A circulating ash load regulating device for a circulating fluidized bed boiler includes a return material device, an ash storage device, an ash storage silo, an ash feeding device, a loosening device, a pressure relief valve, and high and low level gauges. The ash storage device includes an ash inlet pipe, a first manual shut-off valve, and a first electric shut-off valve. One end of the ash inlet pipe is connected and fixed to the return material device, and the other end is inserted into the ash storage silo. The first manual shut-off valve and the first electric shut-off valve are sequentially installed on the ash inlet pipe. The ash feeding device includes an ash outlet pipe, a second manual shut-off valve, a second electric shut-off valve, an electric rotary ash feeder valve, an ash conveying header pipe, and multiple conveying... The ash branch pipe has one end connected to the bottom of the ash storage silo and the other end connected to the inlet of the ash conveying main pipe. Each outlet of the ash conveying main pipe is connected to the corresponding ash conveying branch pipe. The ash branch pipe is provided with a second manual shut-off valve, a second electric shut-off valve and an electric rotary ash feeding valve from top to bottom. The loosening device includes a vibrating device and a compressed air actuation pipeline. The vibrating device is installed on the side wall of the ash storage silo. The compressed air actuation pipeline is inserted into the ash storage silo. The pressure relief valve is inserted into the ash storage silo. The high and low level gauges are installed on the side wall of the ash storage silo.

[0006] Furthermore, the two probes of the high and low level gauges are respectively installed between the high and low level points of the ash storage silo.

[0007] Furthermore, the electric rotary ash feeder valve is connected and fixedly connected to the high-pressure fluidizing air duct.

[0008] Furthermore, the top of the ash storage silo is covered with a tarpaulin.

[0009] Furthermore, the ash inlet pipe, compressed air actuation pipe, and pressure relief valve are all inserted into the ash storage silo through the tarpaulin.

[0010] Furthermore, each of the ash conveying branch pipes is equipped with a high-temperature resistant isolation valve.

[0011] Furthermore, the first manual shut-off valve and the second manual shut-off valve remain in the normally open state.

[0012] Furthermore, the ash inlet pipe is made of a high-temperature resistant material.

[0013] A method for regulating the circulating ash load of a circulating fluidized bed boiler includes an ash storage process and an ash addition process. The ash storage process involves closing a second electric shut-off valve and opening a first electric shut-off valve to store ash from the return material device into an ash storage silo. The ash addition process involves closing the first electric shut-off valve, opening a compressed air actuation system to introduce compressed air into the ash storage silo to loosen the ash at the bottom of the silo, and simultaneously using a rapping device to vibrate the side wall of the ash storage silo to allow the loosened ash to flow downwards smoothly into the ash outlet pipe. The second electric shut-off valve, the electric rotary ash feed valve, and the high-pressure fluidizing air pipeline are opened sequentially to allow the ash to smoothly enter the ash conveying main pipe. The high-temperature isolation valve is opened, allowing the ash in the ash conveying main pipe to enter the furnace through the ash conveying branch pipe.

[0014] Furthermore, the ash storage process is used for boiler operation at reduced load, and the ash addition process is used for boiler operation at increased load.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] The present invention can effectively store ash in the furnace into the ash storage bin through the ash storage device, and can add ash from the ash storage bin into the furnace in a timely manner through the ash adding device, thereby achieving the technical effect of rapidly increasing or decreasing the boiler load as required.

[0017] This invention achieves precise control of the ash storage and ash addition amounts in the ash storage and ash addition processes through the first electric shut-off valve in the ash storage device and the second electric shut-off valve and electric rotary ash feeding valve in the ash addition device, thereby improving the device's response speed and enabling rapid increases and decreases in boiler load.

[0018] The present invention provides alternative solutions for the ash storage and ash addition processes by setting a first manual shut-off valve in the ash storage device and a second manual shut-off valve in the ash addition device. Even in the event of a power outage or other emergency, the ash storage and ash addition amounts can still be accurately controlled, ensuring the safe and stable operation of the device.

[0019] This invention, through an ash storage device and an ash adding device, enables the fine ash separated from a circulating fluidized bed boiler to increase or decrease the load according to the boiler's needs. It can store and retrieve the ash at any time, has a fast system response, safe and stable operation, convenient maintenance, and reduces operating costs. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 This is a front view of the circulating ash load regulating device for a circulating fluidized bed boiler.

[0022] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0023] In the diagram: 1. Return material device; 2. Ash inlet pipe; 3. First manual shut-off valve; 4. First electric shut-off valve; 5. Ash storage silo; 6. Vibrating device; 7. Ash outlet pipe; 8. Electric rotary ash feeder valve; 9. High-pressure fluidizing air duct; 10. Ash conveying main pipe; 10-1. Ash conveying main pipe inlet; 10-2. Ash conveying main pipe outlet; 11. Ash conveying branch pipe; 12. High-temperature resistant isolation valve; 13. Compressed air actuation duct; 14. Pressure relief valve; 15. High and low level gauges; 16. Furnace chamber; 17. Cloth covering; 18. Second manual shut-off valve; 19. Second electric shut-off valve. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0025] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] See attached Figure 1-2This embodiment describes a circulating ash load regulating device for a circulating fluidized bed boiler. The inlet of this device is located below the return material device of the circulating fluidized bed boiler, and the outlet is connected to the conical section of the furnace. The overall height is the same as the entry elevation of the return material device. It includes a return material device 1, an ash storage device, an ash storage silo 5, an ash feeding device, a loosening device, a pressure relief valve 14, and a high / low level gauge 15. The ash storage device includes an ash inlet pipe 2, a first manual shut-off valve 3, and a first electric shut-off valve 4. One end of the ash inlet pipe 2 is connected and fixed to the return material device 1, and the other end is inserted into the ash storage silo 5. The first manual shut-off valve 3 and the first electric shut-off valve 4 are sequentially installed on the ash inlet pipe 2. The ash feeding device includes an ash outlet pipe 7, a second manual shut-off valve 18, a second electric shut-off valve 19, an electric rotary ash feed valve 8, an ash conveying main pipe 10, and multiple ash conveying branch pipes 11. One end of the ash outlet pipe 7... The bottom of the ash storage silo 5 is connected and fixed. The other end of the ash discharge pipe 7 is connected and fixed to the inlet 10-1 of the ash conveying main pipe. Each ash conveying main pipe outlet 10-2 is connected and fixed to the corresponding ash conveying branch pipe 11. From top to bottom, the ash discharge pipe 7 is equipped with a second manual shut-off valve 18, a second electric shut-off valve 19, and an electric rotary ash feeding valve 8. The loosening device includes a vibrating device 6 and a compressed air actuation pipe 13. The vibrating device 6 is installed on the side wall of the ash storage silo 5. The compressed air actuation pipe 13 is inserted into the ash storage silo 5. The pressure relief valve 14 is inserted into the ash storage silo 5. The high and low level gauges 15 are installed on the side wall of the ash storage silo 5. Specifically, the compressed air actuation pipe 13 is equipped with a compressed air actuation valve. Specifically, the ash conveying main pipe 10 has one ash conveying main pipe inlet 10-1 and at least two ash conveying main pipe outlets 10-2.

[0027] This invention effectively stores ash from the furnace 16 into the ash storage bin 5 via an ash storage device, and promptly adds ash from the ash storage bin 5 into the furnace 16 via an ash adding device, achieving the technical effect of rapidly adjusting the boiler load as required. This invention achieves precise control of the ash storage and addition processes through the first electric shut-off valve 4 in the ash storage device, the second electric shut-off valve 19 in the ash adding device, and the electric rotary ash feeding valve 8, improving the device's response speed and enabling rapid adjustments to the boiler load. This invention provides alternative solutions for the ash storage and addition processes through the first manual shut-off valve 3 in the ash storage device and the second manual shut-off valve 18 in the ash adding device, ensuring accurate control of the ash storage and addition amounts even in the event of a power outage or other emergency, guaranteeing safe and stable operation of the device. This invention, through the ash storage and ash adding devices, allows for adjusting the load of fine ash separated from the circulating fluidized bed boiler according to boiler needs, enabling on-demand storage and retrieval, reducing operating costs, facilitating maintenance, improving system response speed, and ensuring safe and stable operation.

[0028] The two probes of the high and low level gauges 15 are respectively installed between the high and low level points of the ash storage silo 5. Specifically, the high level point is the position in the ash storage silo 5 where the maximum allowable ash storage capacity is, and the low level point is the position in the ash storage silo 5 where the minimum allowable ash storage capacity is. By detecting the ash storage capacity in the ash storage silo 5 through the high and low level gauges 15, and by installing the probes of the high and low level gauges 15 between the high and low level points of the ash storage silo 5, it is ensured that the pressure inside the ash storage silo 5 is maintained within the normal range. When the pressure inside the ash storage silo 5 is detected to be too high, the pressure is released through the pressure relief valve 14.

[0029] The electric rotary ash feeder valve 8 is connected and fixedly connected to the high-pressure fluidizing air duct 9. The electric rotary ash feeder valve 8 allows ash to smoothly enter the ash conveying main pipe 10, and the high-pressure fluidizing air duct 9 is supplied with high-pressure fluidizing air to prevent ash from escaping from the electric rotary ash feeder valve 8. The high-pressure fluidizing air duct 9 plays a role in sealing and promoting flow.

[0030] The top of the ash storage silo 5 is covered with a tarpaulin 17. This tarpaulin 17 is used to prevent dust from being emitted.

[0031] The ash inlet pipe 2, the compressed air actuation pipe 13, and the pressure relief valve 14 are all inserted into the ash storage silo 5 through the tarpaulin 17.

[0032] Each of the ash conveying branch pipes 11 is equipped with a high-temperature isolation valve 12. The high-temperature isolation valve can cut off the ash feeding device and prevent ash in the furnace from being transferred back to the ash storage silo 5.

[0033] The first manual shut-off valve 3 and the second manual shut-off valve 18 remain normally open. Specifically, the first manual shut-off valve 3 and the second manual shut-off valve 18 can precisely control the ash storage and ash addition amounts through manual control during power outages or other emergencies.

[0034] The ash inlet pipe 2 is made of a high-temperature resistant material. Preferably, the ash inlet pipe 2 is made of high-temperature resistant stainless steel.

[0035] A method for regulating the circulating ash load of a circulating fluidized bed boiler includes an ash storage process and an ash addition process. The ash storage process involves closing the second electric shut-off valve 19, opening the first electric shut-off valve 4, and storing the ash in the return material device 1 into the ash storage silo 5. The ash addition process involves closing the first electric shut-off valve 4, opening the compressed air actuation system to introduce compressed air into the ash storage silo 5 to loosen the ash at the bottom of the ash storage silo 5, and simultaneously, the vibrating device 6 vibrates the side wall of the ash storage silo 5 to make the loosened ash flow downward smoothly into the ash outlet pipe 7. The second electric shut-off valve 19, the electric rotary ash feed valve 8, and the high-pressure fluidizing air pipe 9 are opened in sequence to make the ash smoothly enter the ash conveying main pipe 10. The high-temperature resistant isolation valve 12 is opened, and then the ash in the ash conveying main pipe 10 enters the furnace 16 through the ash conveying branch pipe 11. Specifically, when the circulating fluidized bed boiler is operating at a stable load and the circulating ash load does not require adjustment, the first manual shut-off valve 3 is normally open, the first electric shut-off valve 4 is closed, and the high-temperature isolation valve 12 of the ash conveying branch pipe is closed. When the circulating fluidized bed boiler needs to reduce its load, the furnace heat exchange does not require excessive circulating material, and the ash carried by the flue gas at the furnace outlet is separated and enters the return material device 1. At this time, the first electric shut-off valve 4 on the ash inlet pipe can be opened to allow the ash to enter the ash storage bin 5 for storage. When the circulating fluidized bed boiler needs to increase its load... When needed, the furnace heat exchange requires more circulating material. Since this system has not been used for a long time, the ash in the ash storage bin will be compacted due to natural sedimentation. The rapping device on the side wall can be turned on to loosen the ash in the bin. The compressed air actuation system can be turned on to introduce pressurized compressed air into the bin, which will cause the ash in the bin to flow downward smoothly into the ash outlet pipe 7. The ash will then be smoothly introduced into the ash conveying main pipe by the electric rotary ash feed valve 8. In order to prevent the ash from leaking out of the electric rotary ash feed valve 8, high-pressure fluidizing air is introduced into the high-pressure fluidizing air pipe 9 to play a sealing and actuating role. The entire process is strictly designed to prevent ash leakage and measures are taken to ensure reliable sealing.

[0036] This invention uses a compressed air actuation system to loosen the ash at the bottom of the ash storage bin 5, and a vibrating device 6 to vibrate the side wall so that the loosened ash enters the ash outlet pipe 7, which can ensure that the ash can be smoothly output even if it is compacted due to long-term storage in the bin.

[0037] The ash storage process is used for boiler operation with reduced load, and the ash addition process is used for boiler operation with increased load.

[0038] Obviously, the above-disclosed embodiments of the present invention are merely for illustrating the present invention. The embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. It is neither necessary nor possible to exhaustively describe all implementation methods herein.

Claims

1. A circulating ash load regulating device for a circulating fluidized bed boiler, characterized in that: The device includes a return material device (1), an ash storage device, an ash storage silo (5), an ash feeding device, a loosening device, a pressure relief valve (14), and a high and low level gauge (15). The ash storage device includes an ash inlet pipe (2), a first manual shut-off valve (3), and a first electric shut-off valve (4). One end of the ash inlet pipe (2) is connected to the return material device (1), and the other end of the ash inlet pipe (2) is inserted into the ash storage silo (5). The first manual shut-off valve (3) and the first electric shut-off valve (4) are sequentially installed on the ash inlet pipe (2). The ash feeding device includes an ash outlet pipe (7), a second manual shut-off valve (18), a second electric shut-off valve (19), an electric rotary ash feeding valve (8), an ash conveying main pipe (10), and multiple ash conveying branch pipes (11). One end of the ash outlet pipe (7) is connected to the bottom of the ash storage silo (5). The other end of the ash discharge pipe (7) is connected and fixed to the inlet (10-1) of the ash conveying main pipe. Each ash conveying main pipe outlet (10-2) is connected and fixed to the corresponding ash conveying branch pipe (11). The ash in the ash conveying main pipe (10) enters the furnace (16) through the ash conveying branch pipe (11). The ash discharge pipe (7) is provided with a second manual shut-off valve (18), a second electric shut-off valve (19) and an electric rotary ash feeding valve (8) from top to bottom. The loosening device includes a vibrating device (6) and a compressed air actuation pipe (13). The vibrating device (6) is installed on the side wall of the ash storage silo (5). The compressed air actuation pipe (13) is inserted into the ash storage silo (5). The pressure relief valve (14) is inserted into the ash storage silo (5). The high and low level gauge (15) is installed on the side wall of the ash storage silo (5).

2. The circulating ash load regulating device for a circulating fluidized bed boiler according to claim 1, characterized in that: The two probes of the high and low level gauge (15) are respectively installed between the high and low level points of the ash storage silo (5).

3. The circulating ash load regulating device for a circulating fluidized bed boiler according to claim 1, characterized in that: The electric rotary ash feeder valve (8) is connected and fixed to the high-pressure fluidizing air duct (9).

4. The circulating ash load regulating device for a circulating fluidized bed boiler according to claim 1, characterized in that: The top of the ash storage silo (5) is covered with a tarpaulin (17).

5. A circulating ash load regulating device for a circulating fluidized bed boiler according to claim 4, characterized in that: The ash inlet pipe (2), compressed air actuation pipe (13) and pressure relief valve (14) are all inserted into the ash storage silo (5) through the tarpaulin (17).

6. The circulating ash load regulating device for a circulating fluidized bed boiler according to claim 1, characterized in that: Each of the ash conveying branch pipes (11) is equipped with a high-temperature resistant isolation valve (12).

7. The circulating ash load regulating device for a circulating fluidized bed boiler according to claim 1, characterized in that: The first manual shut-off valve (3) and the second manual shut-off valve (18) remain in the normally open state.

8. The circulating ash load regulating device for a circulating fluidized bed boiler according to claim 1, characterized in that: The ash inlet pipe (2) is made of high-temperature resistant material.

9. A method for adjusting the circulating ash load regulating device of a circulating fluidized bed boiler as described in any one of claims 1 to 8, characterized in that: The process includes ash storage and ash addition. The ash storage process involves closing the second electric shut-off valve (19), opening the first electric shut-off valve (4), and storing the ash in the return material device (1) into the ash storage silo (5). The ash addition process involves closing the first electric shut-off valve (4), opening the compressed air actuation system to introduce compressed air into the ash storage silo (5) to loosen the ash at the bottom of the ash storage silo (5), and at the same time, the vibrating device (6) vibrates the side wall of the ash storage silo (5) to make the loosened ash flow downward smoothly into the ash outlet pipe (7). The second electric shut-off valve (19), the electric rotary ash feeding valve (8), and the high-pressure fluidizing air pipe (9) are opened in sequence to make the ash smoothly enter the ash conveying main pipe (10). The high-temperature isolation valve (12) is opened, and then the ash in the ash conveying main pipe (10) enters the furnace (16) through the ash conveying branch pipe (11).

10. The adjustment method according to claim 9, characterized in that: The ash storage process is used for boiler operation with reduced load, and the ash addition process is used for boiler operation with increased load.

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