Boiler flue gas recirculation device

Abstract

The invention discloses a boiler flue gas recirculation device, which belongs to the technical field of power plant boiler flue gas treatment, and comprises a mounting plate, a waste heat recovery mechanism and an external control system, wherein a boiler and a secondary combustion chamber are arranged on the mounting plate; the waste heat recovery mechanism comprises a flue gas extraction pipeline, a heat exchange pipeline and a waste heat recovery chamber; the two ends of the smoke extraction pipeline communicate with the exhaust end of the boiler and the air inlet end of the secondary combustion chamber correspondingly. One end of the heat exchange pipeline is communicated with the flue gas extraction pipeline and is arranged close to the tail part of the flue gas extraction pipeline, and the other end of the heat exchange pipeline is detachably communicated with the waste heat recovery chamber; the waste heat recovery chamber is arranged at the side part of the secondary combustion chamber; the external control system is used for adjusting the running state of the whole device; according to the design, the combustion efficiency and the operation stability of the boiler can be improved, and energy waste and pollutant emission are reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue gas treatment for power plant boilers, and particularly relates to a boiler flue gas recirculation device. Background Art

[0002] As an important energy conversion device, power plant boilers play an indispensable role in power production, power supply, heating and other fields. However, there are many problems in the operation of traditional boiler combustion systems, which not only affect the combustion efficiency of the boilers, but also lead to energy waste and environmental pollution aggravation. For example:

[0003] First, during the boiler combustion process, some large solid particles (such as biomass particles, etc.) cannot be completely burned in the primary combustion. These incompletely burned large solid particles will be discharged with the flue gas, resulting in air pollution; in order to achieve the secondary combustion of these large solid particles, additional heat is usually required to improve the combustion efficiency; in addition, the flue gas from the primary combustion also has residual heat, and if not collected, it will lead to energy waste;

[0004] Second, during the long-term operation of boiler pipes, dust and particulate matter are likely to accumulate on the inner wall. These ash deposits will reduce the heat exchange efficiency of the pipes, increase the airflow resistance, and may even cause pipe blockage, affecting the normal operation of the boilers;

[0005] In view of the deficiencies of the prior art, the present invention provides a boiler flue gas recirculation device, aiming to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a boiler flue gas recirculation device, which can improve the combustion efficiency and operation stability of the boiler, and reduce energy waste and pollutant emissions.

[0007] To achieve the above purpose, the present invention is implemented by the following technical solutions:

[0008] A boiler flue gas recirculation device, comprising:

[0009] A mounting plate, on which a boiler and a secondary combustion chamber are provided;

[0010] A waste heat recovery mechanism, which includes a flue gas extraction pipeline, a heat exchange pipeline and a waste heat recovery chamber; wherein,

[0011] Both ends of the flue gas extraction pipeline are respectively communicated with the exhaust end of the boiler and the intake end of the secondary combustion chamber;

[0012] One end of the heat exchange pipeline is communicated with the flue gas extraction pipeline and is arranged near the tail of the flue gas extraction pipeline, and the other end of the heat exchange pipeline is detachably communicated with the waste heat recovery chamber;

[0013] The waste heat recovery chamber is arranged on the side of the secondary combustion chamber;

[0014] And an external control system for adjusting the operating state of the whole device.

[0015] Preferably, a heat exchanger, a partition board and a heat medium channel are arranged in the waste heat recovery chamber;

[0016] The input end of the heat exchanger is communicated with the output end of the heat exchange pipeline, its output end is connected with the partition board, and through holes are arranged on the partition board;

[0017] The input end of the heat medium channel is connected with the other end of the partition board and is communicated with the through hole, and the output end of the heat medium channel is communicated with the heating chamber of the secondary combustion chamber.

[0018] Preferably, a serpentine smoke passing pipeline and a plurality of combustion nozzles are arranged in the secondary combustion chamber;

[0019] The input end of the serpentine smoke passing pipeline is communicated with the tail of the flue gas extraction pipeline, the output end of the serpentine smoke passing pipeline is communicated with an exhaust pipe, the exhaust pipe is communicated with the outside, and an exhaust valve is arranged on the exhaust pipe;

[0020] A plurality of the combustion nozzles are uniformly installed on the inner wall of the secondary combustion chamber, the combustion nozzles are all connected with an external ignition device, and the external ignition device is opened and closed through the external control system.

[0021] Preferably, an air extraction fan and a second filter plate are arranged in the heat exchange pipeline; the second filter plate is arranged between the air extraction fan and the waste heat recovery chamber.

[0022] Preferably, a one-way control valve is arranged at the tail of the flue gas extraction pipeline.

[0023] Preferably, a second control valve is arranged on the heat medium channel.

[0024] Preferably, the waste heat recovery mechanism further includes a temperature sensor, and the temperature sensor is arranged at the outlet of the heat exchanger.

[0025] Preferably, a pipe wall cleaning mechanism is further included, the pipe wall cleaning mechanism includes a first filter plate, a plurality of convex sliders are arranged on the outer periphery of the first filter plate, and each convex slider is slidably connected in a slide rail formed on the inner wall of the flue gas extraction pipeline, and realizes its own linear motion through the pushing of the air flow in the pipeline.

[0026] Preferably, the second filter plate and the first filter plate are made of materials with high temperature resistance, corrosion resistance and wear resistance.

[0027] Compared with the prior art, the beneficial effects achieved by the present invention:

[0028] 1. The present invention designs a waste heat recovery mechanism, which can effectively recover the waste heat in the high-temperature flue gas discharged from the boiler, transfer it into the secondary combustion chamber for assisting secondary combustion, reduce the additional heat required for secondary combustion, thereby improving the energy utilization efficiency and reducing energy waste; the secondary combustion provides a space for the unburned large solid particles to burn again. Through the evenly distributed combustion nozzles and external ignition devices, it can ensure that these particles burn fully, thus significantly reducing the pollutant emissions caused by incomplete combustion and improving air quality.

[0029] 2. The present invention designs a pipe wall cleaning mechanism. By the airflow in the pipeline pushing the filter plate one to move linearly in the pipeline, it can effectively clean the ash and particulate matter on the inner wall of the pipeline, reduce the influence of ash accumulation on the heat exchange efficiency, and the tail of the flue gas extraction pipeline is detachably connected to the secondary combustion chamber. When the filter plate one moves to the tail of the flue gas extraction pipeline, it is disassembled, and then the filter plate one is pushed to the very beginning of the flue gas extraction pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic structural diagram of the present invention.

[0031] Figure 2 is a schematic structural diagram of the waste heat recovery mechanism and the secondary combustion chamber of the present invention.

[0032] Figure 3 is a schematic structural diagram of the pipe wall cleaning mechanism of the present invention.

[0033] Figure 4 is a schematic structural diagram of another perspective of the present invention.

[0034] Wherein:

[0035] 1. Mounting plate; 2. Boiler; 3. Waste heat recovery mechanism; 31. Flue gas extraction pipeline; 311. Slide rail; 312. One-way control valve; 32. Heat exchange pipeline; 320. Exhaust fan; 321. Filter plate two; 33. Waste heat recovery chamber; 331. Heat exchanger; 333. Partition board; 333a. Through hole; 334. Heat medium channel; 334a. Control valve two; 4. Secondary combustion chamber; 40. Heating cavity; 41. Combustion nozzle; 42. Serpentine smoke passage pipeline; 43. Exhaust pipe; 44. Exhaust valve; 5. Pipe wall cleaning mechanism; 51. Filter plate one; 52. Convex slider. DETAILED DESCRIPTION OF THE INVENTION

[0036] The present invention will be further described below with reference to the drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and cannot be used to limit the protection scope of the present invention.

[0037] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "middle", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more than two.

[0038] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0039] Embodiment 1

[0040] Reference Figures 1-4 , this embodiment provides a flue gas recirculation device for a boiler 2, including:

[0041] A mounting plate 1, on which a boiler 2 and a secondary combustion chamber 4 are provided;

[0042] A waste heat recovery mechanism 3, which includes a flue gas extraction pipeline 31, a heat exchange pipeline 32, and a waste heat recovery chamber 33; wherein,

[0043] Both ends of the flue gas extraction pipeline 31 are respectively communicated with the exhaust end of the boiler 2 and the intake end of the secondary combustion chamber 4;

[0044] One end of the heat exchange pipeline 32 is communicated with the flue gas extraction pipeline 31 and is arranged near the tail of the flue gas extraction pipeline 31, and the other end of the heat exchange pipeline 32 is detachably communicated with the waste heat recovery chamber 33;

[0045] The waste heat recovery chamber 33 is arranged on the side of the secondary combustion chamber 4;

[0046] And an external control system for adjusting the operating state of the entire device.

[0047] Specifically, a heat exchanger 331, a partition 333, and a heat medium channel 334 are provided in the waste heat recovery chamber 33;

[0048] The input end of the heat exchanger 331 is communicated with the output end of the heat exchange pipeline 32, its output end is connected to the partition plate 333, and a through hole 333a is provided on the partition plate 333;

[0049] The input end of the heat medium channel 334 is connected to the other end of the partition plate 333 and is communicated with the through hole 333a, and the output end of the heat medium channel 334 is communicated with the heating chamber 40 of the secondary combustion chamber 4.

[0050] In order to achieve efficient extraction and re - filtration of flue gas, in this embodiment, an air extraction fan 320 and a second filter plate 321 are provided in the heat exchange pipeline 32; the second filter plate 321 is arranged between the air extraction fan 320 and the waste heat recovery chamber 33.

[0051] In order to be able to precisely control the flow rate of the heat medium, in this embodiment, a second control valve 334a is provided on the heat medium channel 334. This design can flexibly adjust the supply amount of the heat medium according to the actual needs of the secondary combustion chamber 4, ensuring the stability and efficiency of the secondary combustion process.

[0052] In order to be able to monitor the temperature of the heat medium in real - time and provide accurate temperature data for the external control system, in this embodiment, the waste heat recovery mechanism 3 further includes a temperature sensor, and the temperature sensor is arranged at the outlet of the heat exchanger 331. This design is convenient for timely adjusting the system operation parameters to ensure the stability and efficiency of the waste heat recovery and secondary combustion processes.

[0053] In order to prevent the backflow of flue gas and ensure that the flue gas can only flow unidirectionally, in this embodiment, a one - way control valve 312 is provided at the tail of the flue gas extraction pipeline 31 to prevent the flue gas in the secondary combustion chamber 4 from being sucked back into the waste heat recovery chamber 33.

[0054] Specifically, a serpentine smoke - passing pipeline 42 and a plurality of combustion nozzles 41 are provided in the secondary combustion chamber 4;

[0055] The input end of the serpentine smoke - passing pipeline 42 is communicated with the tail of the flue gas extraction pipeline 31, the output end of the serpentine smoke - passing pipeline 42 is communicated with an exhaust pipe 43, the exhaust pipe 43 is communicated with the outside, and an exhaust valve 44 is provided on the exhaust pipe 43;

[0056] A plurality of the combustion nozzles 41 are uniformly installed on the inner wall of the secondary combustion chamber 4, and the combustion nozzles 41 are all connected to an external ignition device, and the external ignition device is opened and closed through an external control system.

[0057] In this embodiment, the present invention designs a waste heat recovery mechanism 3, which can effectively recover the waste heat in the high-temperature flue gas discharged from the boiler 2 and transfer it into the secondary combustion chamber 4 for assisting secondary combustion, reducing the additional heat required for secondary combustion, thereby improving the energy utilization efficiency and reducing energy waste; the secondary combustion provides a space for the unburned large solid particles to burn again, and through the evenly distributed combustion nozzles 41 and external ignition equipment, it can ensure that these particles burn fully, thereby significantly reducing the pollutant emissions caused by incomplete combustion and improving air quality.

[0058] Embodiment 2

[0059] On the basis of Embodiment 1, referring to Figure 3 , the present invention also has the following design.

[0060] Furthermore, the flue gas recirculation device designed by the present invention further includes a pipe wall cleaning mechanism 5, and the pipe wall cleaning mechanism 5 includes a first filter plate 51. A plurality of protruding sliders 52 are arranged on the outer periphery of the first filter plate 51, and each of the protruding sliders 52 is slidably connected to a slide rail 311 opened on the inner wall of the flue gas extraction pipe 31, and realizes its linear motion through the push of the airflow in the pipe.

[0061] It should be noted that in this embodiment, the present invention designs the pipe wall cleaning mechanism 5. By pushing the first filter plate 51 to move linearly in the pipe through the airflow in the pipe, it can effectively clean the ash and particulate matter on the inner wall of the pipe, reduce the influence of ash accumulation on the heat exchange efficiency, and the tail of the flue gas extraction pipe 31 is detachably connected to the secondary combustion chamber 4. When the first filter plate 51 moves to the tail of the flue gas extraction pipe 31, it is disassembled, and then the first filter plate 51 is pushed to the very beginning of the flue gas extraction pipe 31.

[0062] Preferably, the first filter plate 51 can also assist the external driving device to realize its reciprocating motion.

[0063] In order to ensure the long-term stable operation of the filter plate, in this embodiment, the second filter plate 321 and the first filter plate 51 are made of materials with high temperature resistance, corrosion resistance and wear resistance.

[0064] Working principle:

[0065] 1. Flue gas extraction and transportation

[0066] Flue gas extraction: The high-temperature flue gas generated by the combustion of the boiler 2 is discharged from the exhaust end of the boiler 2 and is extracted by an air extraction fan 320 through the flue gas extraction pipe 31. The air extraction fan 320 is installed in the heat exchange pipe 32 to ensure that the flue gas can smoothly flow from the boiler 2 -> heat exchanger 331 -> secondary combustion chamber 4.

[0067] Pipeline transportation: The extracted flue gas flows along the flue gas extraction pipeline 31, and passes through the first filter plate 51 for preliminary filtration to remove large particle impurities, preventing these impurities from entering the subsequent waste heat recovery mechanism 3 and protecting equipment such as the heat exchanger 331 from blockage and wear.

[0068] 2. Waste heat recovery

[0069] Heat exchange process: The preliminarily filtered flue gas enters the heat exchange pipeline 32 and exchanges heat with the heat medium in the heat exchanger 331. The input end of the heat exchanger 331 is connected to the output end of the heat exchange pipeline 32, and the heat medium absorbs the waste heat of the flue gas in the heat exchanger 331 and the temperature rises.

[0070] Heat medium circulation: The heat medium that has absorbed the waste heat is transported to the waste heat recovery chamber 33 through the heat medium channel 334. The output end of the heat medium channel 334 is connected to the heating chamber 40 of the secondary combustion chamber 4, releasing the heat in the heat medium into the secondary combustion chamber 4 to assist the secondary combustion process.

[0071] Temperature control: A temperature sensor is installed at the outlet of the heat exchanger 331 to monitor the temperature of the heat medium in real time and feed the data back to the external control system. The external control system adjusts the flow rate of the heat medium channel 334 through the second control valve 334a according to the signal of the temperature sensor to ensure that the temperature of the heat medium remains within the set range, thereby realizing precise control of the waste heat recovery process.

[0072] 3. Secondary combustion

[0073] Flue gas entry: The flue gas after waste heat recovery enters the secondary combustion chamber 4 through the serpentine flue gas pipeline 42. The design of the serpentine flue gas pipeline 42 increases the residence time of the flue gas in the secondary combustion chamber 4 and improves the combustion efficiency.

[0074] Combustion process: A plurality of combustion nozzles 41 in the secondary combustion chamber 4 are evenly distributed on the inner wall, and the combustion nozzles 41 are connected to the external ignition device. The external ignition device is opened and closed through the external control system to ignite the large solid particles that are not completely burned, so that they burn fully in the secondary combustion chamber 4.

[0075] Exhaust gas treatment: The burned flue gas is discharged through the exhaust pipe 43, and an exhaust valve 44 is provided on the exhaust pipe 43 to control the exhaust gas flow rate and ensure the pressure stability in the secondary combustion chamber 4.

[0076] 4. Pipeline cleaning

[0077] Cleaning mechanism: A pipe wall cleaning mechanism 5 is installed in the flue gas extraction pipeline 31, including a second filter plate 321 and a plurality of convex sliders 52. The second filter plate 321 is provided with convex sliders 52 on its outer periphery, and the convex sliders 52 are slidably connected to the slide rails 311 opened on the inner wall of the flue gas extraction pipeline 31.

[0078] Filter plate 1 51 linear motion: When the flue gas passes through the flue gas extraction pipe 31, the airflow pushes the filter plate 2 321 to move linearly along the slide rail 311 inside the pipe. During the movement of the filter plate 2 321, it scrapes the dust and particulate matter on the inner wall of the pipe, preventing the accumulation of dust and maintaining the smoothness of the pipe. When the filter plate 1 51 moves to the tail of the flue gas extraction pipe 31, it is disassembled, and then the filter plate 1 51 is pushed to the very beginning of the flue gas extraction pipe 31.

[0079] In summary, through the coordinated action of each mechanism, the flue gas recirculation device of the boiler 2 of the present invention realizes the effective recovery and utilization of waste heat, the efficient progress of secondary combustion, and the automatic cleaning of the inner wall of the pipe, significantly improving the combustion efficiency, energy utilization efficiency, and operation stability of the boiler 2 system. At the same time, it reduces pollutant emissions and equipment maintenance costs, providing an effective solution for energy conservation, emission reduction, and sustainable development in the boiler 2 industry.

[0080] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A boiler flue gas recirculation device, characterized in that, Comprising: An installation plate (1) provided with a boiler (2) and a secondary combustion chamber (4) thereon; A waste heat recovery mechanism (3), which includes a flue gas extraction pipe (31), a heat exchange pipe (32), and a waste heat recovery chamber (33); wherein, Both ends of the flue gas extraction pipe (31) are respectively communicated with the exhaust end of the boiler (2) and the intake end of the secondary combustion chamber (4); One end of the heat exchange pipe (32) is communicated with the flue gas extraction pipe (31) and is arranged near the tail of the flue gas extraction pipe (31), and the other end of the heat exchange pipe (32) is detachably communicated with the waste heat recovery chamber (33); The waste heat recovery chamber (33) is arranged at the side of the secondary combustion chamber (4); And an external control system for adjusting the operating state of the entire device.

2. The boiler flue gas recirculation device according to claim 1, wherein A heat exchanger (331), a partition plate (333), and a heat medium channel (334) are arranged in the waste heat recovery chamber (33); The input end of the heat exchanger (331) is communicated with the output end of the heat exchange pipe (32), its output end is connected to the partition plate (333), and through holes (333a) are arranged on the partition plate (333); The input end of the heat medium channel (334) is connected to the other end of the partition plate (333) and is communicated with the through holes (333a), and the output end of the heat medium channel (334) is communicated with the heating chamber (40) of the secondary combustion chamber (4).

3. The boiler flue gas recirculation device according to claim 1, characterized in that, A serpentine flue gas pipe (42) and a plurality of combustion nozzles (41) are arranged in the secondary combustion chamber (4); The input end of the serpentine flue gas pipe (42) is communicated with the tail of the flue gas extraction pipe (31), the output end of the serpentine flue gas pipe (42) is communicated with an exhaust pipe (43), the exhaust pipe (43) is communicated with the outside, and an exhaust valve (44) is arranged on the exhaust pipe (43); A plurality of the combustion nozzles (41) are evenly installed on the inner wall of the secondary combustion chamber (4), the combustion nozzles (41) are all connected to an external ignition device, and the external ignition device is opened and closed through the external control system.

4. The boiler flue gas recirculation device according to claim 1, characterized in that An air extraction fan (320) and a second filter plate (321) are arranged in the heat exchange pipe (32); the second filter plate (321) is arranged between the air extraction fan (320) and the waste heat recovery chamber (33).

5. The boiler flue gas recirculation device according to claim 1, characterized in that, A one-way control valve (312) is arranged at the tail of the flue gas extraction pipe (31).

6. The boiler flue gas recirculation device according to claim 2, wherein, A second control valve (334a) is arranged on the heat medium channel (334).

7. The boiler flue gas recirculation device according to claim 2, wherein, The waste heat recovery mechanism (3) further includes a temperature sensor arranged at the outlet of the heat exchanger (331).

8. The boiler flue gas recirculation device according to claim 1, characterized in that, It further includes a pipe wall cleaning mechanism (5), which includes a first filter plate (51), and a plurality of convex sliders (52) are arranged on the outer periphery of the first filter plate (51), and each of the convex sliders (52) is slidably connected in a slide rail (311) opened on the inner wall of the flue gas extraction pipe (31) and realizes its own linear motion by the push of the airflow in the pipe.

9. The boiler flue gas recirculation device according to claim 4 or 8, characterized in that, The second filter plate (321) and the first filter plate (51) are made of materials with high temperature resistance, corrosion resistance, and wear resistance.

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