Secondary air box ash discharging device and using method

Abstract

The invention relates to the field of thermal power generating unit environmental protection, and discloses a secondary air bellow ash discharging device and a using method, the secondary air bellow ash discharging device comprises a main body mechanism and an ash suction mechanism, the main body mechanism comprises a main component and at least two exhaust components installed on the outer side of the main component, and the ash suction mechanism comprises a connecting component installed on the outer side of the exhaust components. The dust suction mechanism is installed between every two adjacent air exhaust components, the dust accumulation amount detection module is connected with the decentralized controller, and the decentralized controller is connected with the dust suction mechanism. Compared with an existing scheme of'manual ash removal 'and'bottom blowing air ash blowing', the system has the advantages of being high in initiative, controllability and ash removal efficiency, capable of achieving automation of starting and stopping and the like, capable of achieving the benefit of reducing staff and improving efficiency, capable of fully utilizing an existing high-pressure primary air system, low in cost, small in engineering transformation amount, short in construction period and the like.

Description

Technical Field

[0001] The invention relates to the field of environmental protection of thermal power units, and in particular to a secondary wind box ash removal device and a use method thereof. Background Art

[0002] Large power station boilers mostly use swirl burners to organize counter combustion in the furnace. In order to achieve equal air distribution (referring to secondary air, which is used to assist the combustion of pulverized coal entering the furnace) for several swirl coal burners on the same layer, a secondary wind box is set. The secondary wind boxes are symmetrically arranged on the front and rear walls. The designed wind speed in the wind box is relatively low. The secondary wind box can be regarded as a "static pressure wind box". In multi-duct air supply, in order to make the wind pressure of each duct consistent, a static pressure wind box needs to be set to convert all dynamic pressure into static pressure, and then evenly distribute it to each duct. The static pressure wind box is a necessary accessory for the air supply system to reduce dynamic pressure, increase static pressure, stabilize airflow and reduce airflow vibration noise, which can make the air supply effect more ideal. The load of the secondary wind box and the burner is transmitted to the support beam through the wind box truss; one end of the support beam is hinged to the vertical lap plate of the boiler, and the other end is connected to the constant force spring hanger fixed on the steel structure.

[0003] In the power plant boiler system, the air delivered by the blower (called "cold secondary air") first enters the air preheater (abbreviated as air preheater) to absorb the heat of the flue gas, and then becomes "hot secondary air" with a higher temperature. It then enters the furnace through the secondary wind box to supplement the combustion-supporting oxygen for the coal powder entering the furnace.

[0004] In the air preheater, the heat exchange between air and flue gas is carried out through the heat storage element (stacked metal corrugated plates). The flue gas contains a large amount of coal fly ash. After the heat storage element exchanges heat with the corrugated plate, when it exchanges heat with the cold secondary air, the coal fly ash retained on the corrugated plate will be mixed into the hot secondary air, resulting in an increase in the ash content in the hot secondary air. When the hot secondary air enters the large wind box, the flow rate decreases, and gas-solid separation occurs under the action of gravity. A large amount of fly ash settles to the bottom of the wind box, forming a serious internal ash accumulation problem. A large amount of ash accumulation increases the weight of the secondary wind box, which is easy to cause cracking damage to the connection parts, endangering the safety of the boiler equipment. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is: how to discharge the dust accumulated in the secondary air box.

[0006] The above technical problem is solved by the following technical solution: The present invention proposes a secondary air box dust removal device, comprising:

[0007] A main body mechanism, the main body mechanism comprising a main component and an exhaust component installed outside the main component;

[0008] Wherein, the exhaust components are provided with at least two;

[0009] An ash suction mechanism, the ash suction mechanism comprising a connecting component installed on the outside of the exhaust component, and an auxiliary component installed on the outside of the connecting component;

[0010] Wherein, the dust suction mechanism is installed between two adjacent exhaust components;

[0011] A dust accumulation detection module, the dust accumulation detection module is used to detect the dust accumulation inside the main component;

[0012] A distributed controller is electrically connected to the exhaust component, the dust suction mechanism, and the dust accumulation detection module.

[0013] In a preferred embodiment of the secondary air box ash removal device of the present invention: the main components include a secondary air box, and an air inlet fixedly connected to the outer side of the secondary air box.

[0014] In a preferred embodiment of the secondary air box ash discharge device of the present invention: the exhaust component includes a primary air duct fixedly connected to the outside of the secondary air box, a primary air duct valve adapted to be installed inside the primary air duct, and a pulverized coal burner adapted to be installed outside the primary air duct.

[0015] In a preferred embodiment of the secondary air box ash removal device of the present invention: the connecting component includes an air intake pipe fixedly connected to the outside of the primary air duct, an air intake valve adapted to be installed inside the air intake pipe, and an injector adapted to be installed on the outside of the air intake pipe, and a nozzle adapted to be installed on the outside of the injector.

[0016] In a preferred embodiment of the secondary air box ash discharge device of the present invention: the auxiliary component includes an expansion container fixedly connected to the outside of the air inlet pipe, an ash inlet pipe fixedly connected to the outside of the expansion container, and a suction port fixedly connected to the outside of the ash inlet pipe, an air outlet pipe fixedly connected to the outside of the expansion container, and an ash discharge valve adapted to be installed inside the air outlet pipe;

[0017] The ejector and the nozzle are arranged inside the expander, and a small hole is opened outside the suction port.

[0018] In a preferred embodiment of the secondary air box ash removal device of the present invention: the distributed controller is electrically connected to the primary air duct valve, the air inlet valve, the ash discharge valve, and the ash accumulation detection module.

[0019] The invention also provides a use method.

[0020] In a preferred embodiment of the method of use of the present invention: a method of use, for the secondary air box dust removal device, and,

[0021] The bottom of the secondary air box is divided into areas, and an ash suction mechanism is set in each area;

[0022] The dust accumulation detection module detects the dust accumulation in each area in real time;

[0023] When the amount of dust accumulated in a certain area exceeds a preset value, the dust suction mechanism in the area is activated.

[0024] In a preferred embodiment of the method of use of the present invention: n primary air ducts are arranged inside the secondary air box, and a dust suction mechanism is arranged between every two adjacent primary air ducts, that is, n-1 dust suction mechanisms are arranged;

[0025] The bottom of the secondary air box is divided into n-1 areas, and an ash suction mechanism is set in each area.

[0026] In a preferred implementation of the method of use of the present invention: the dust accumulation detection module performs real-time detection of the dust accumulation conditions in each area, and uses the "L1 trend filtering method" to process the data collected by the dust accumulation detection module.

[0027] In a preferred embodiment of the method of use of the present invention: the primary air duct valve of the primary air duct connected to the air inlet pipe of the ash suction mechanism is opened, and the primary air duct valve of the primary air duct connected to the air outlet pipe of the ash suction mechanism is closed;

[0028] The air inlet valve and ash outlet valve of the ash suction mechanism are opened;

[0029] The hot primary air with high temperature and high pressure inside the primary air duct passes through the air inlet pipe and the ejector to become a high-speed primary air flow. The primary air flow passes through the expander and the air outlet pipe and enters the primary air duct. In this process, the dust is sucked into the expander through the small holes inside the suction port and the ash inlet pipe, and follows the primary air flow through the air outlet pipe into the primary air duct, and is then guided by the primary air duct to be discharged from the secondary air box.

[0030] The beneficial effects of the present invention are as follows: compared with the existing solutions of "manual dust cleaning" and "dust blowing with bottom purge air", the present invention has the advantages of strong initiative, high controllability, high dust removal efficiency, and automatic start and stop, and can achieve the benefits of reducing staff and increasing efficiency, and fully utilizes the existing high-pressure primary air system, and has the advantages of low cost, small engineering modification amount, and short construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments of the present invention are briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present invention, but are not intended to limit the present invention. Among them:

[0032] Figure 1The overall structural schematic diagram of the present invention is shown;

[0033] Figure 2 A schematic diagram of a soot blowing mechanism of the present invention is shown;

[0034] Figure 3 shows the original data graph of the present invention;

[0035] Figure 4 The data graph after filtering and noise reduction of the present invention is shown; DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with specific implementation methods and drawings.

[0037] The terms used in the present invention are those general terms currently widely used in the art in consideration of the functions of the present invention, but these terms may vary according to the intention of a person of ordinary skill in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in this case, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but rather as a general description based on the meaning of the terms and the present invention.

[0038] Reference Figure 1 and Figure 2 This embodiment provides a secondary air box dust removal device, including:

[0039] The main body mechanism 1 includes a main component 11 and an exhaust component 12 installed outside the main component 11;

[0040] Wherein, at least two exhaust components 12 are provided;

[0041] The ash suction mechanism 2 includes a connecting component 21 installed on the outside of the exhaust component 12, and an auxiliary component 22 installed on the outside of the connecting component 21;

[0042] The dust suction mechanism 2 is installed between two adjacent exhaust components 12;

[0043] The dust accumulation detection module 3 is used to detect the dust accumulation inside the main component 11;

[0044] The distributed controller 4 is electrically connected to the exhaust component 12 , the dust suction mechanism 2 , and the dust accumulation detection module 3 .

[0045] The main component 11 includes a secondary air box 111 and an air inlet 112 fixedly connected to the outer side of the secondary air box 111 .

[0046] The exhaust component 12 includes a primary air duct 121 fixedly connected to the outside of the secondary air box 111 , a primary air duct valve 122 adapted to be installed inside the primary air duct 121 , and a pulverized coal burner 123 adapted to be installed outside the primary air duct 121 .

[0047] Among them, the dust accumulation detection module 3 is used to detect the amount of dust accumulated at the bottom of the secondary air box 111. It has many specific forms. It can be a level meter of radar, ultrasonic and other types, or an optical measuring element such as a camera, or a single element such as a pressure transmitter or mass weighing.

[0048] It should be pointed out in particular that the dust accumulation detection module 3 includes several sensors deployed in different areas, and these areas are consistent with the dust suction areas of the dust suction mechanism 2. That is to say, each dust suction mechanism 2 has at least one sensor in its working range, and the detection result of the sensor is used to guide the start and stop of the corresponding dust suction mechanism 2.

[0049] A coal mill is disposed at the bottom end of the primary air duct 121 , and the high-temperature and high-pressure hot primary air inside the primary air duct can transport the pulverized coal generated by the coal mill to the pulverized coal burner 123 through the primary air duct 121 .

[0050] As an embodiment provided in this application, Figure 1 and Figure 2 The connecting component 21 includes an air intake pipe 211 fixedly connected to the outside of the primary air duct 121, an air intake valve 212 adapted to be installed inside the air intake pipe 211, an ejector 213 adapted to be installed on the outside of the air intake pipe 211, and a nozzle 214 adapted to be installed on the outside of the ejector 213.

[0051] The auxiliary component 22 includes an expansion container 221 fixedly connected to the outside of the air inlet pipe 211, an ash inlet pipe 222 fixedly connected to the outside of the expansion container 221, and a suction port 223 fixedly connected to the outside of the ash inlet pipe 222, an air outlet pipe 224 fixedly connected to the outside of the expansion container 221, and an ash outlet valve 225 adapted to be installed inside the air outlet pipe 224;

[0052] The ejector 213 and the nozzle 214 are arranged inside the expander 221 , and a small hole is opened outside the suction port 223 .

[0053] The distributed controller 4 is electrically connected to the primary air duct valve 122 , the air inlet valve 212 , the ash discharge valve 225 , and the ash accumulation detection module 3 .

[0054] The hot primary air of high temperature and high pressure becomes a high-speed primary air flow after passing through the ejector 213 .

[0055] Among them, the suction port 223 is installed at the bottom of the secondary air box 111. The form is not fixed. It can be a large cone with holes or a pipe with holes. However, they have a common feature that they can cover the dust accumulation area at the bottom of the secondary air box 111 as much as possible to suck the deposited fly ash.

[0056] The suction port 223 is placed at the bottom of the secondary air box 111 . When dust is accumulated, the accumulated dust will cover it. When the dust suction mechanism 2 is started, the accumulated dust will be sucked into the dust pipe 222 from several small holes on the suction port 223 .

[0057] Reference Figure 1 to Figure 4 , this embodiment provides a method of use for a secondary air box dust removal device, and,

[0058] The bottom of the secondary air box is divided into areas, and an ash suction mechanism is set in each area;

[0059] The dust accumulation detection module detects the dust accumulation in each area in real time;

[0060] When the amount of dust accumulated in a certain area exceeds a preset value, the dust suction mechanism in the area is activated.

[0061] There are n primary air ducts inside the secondary air box, and a dust suction mechanism is set between every two adjacent primary air ducts, that is, n-1 dust suction mechanisms are set;

[0062] The bottom of the secondary air box is divided into n-1 areas, and an ash suction mechanism is set in each area.

[0063] Each single dust suction mechanism and its matching dust accumulation detection module correspond to a single area at the bottom of the secondary air box. For example, when the dust accumulation detection module installed in a certain area at the bottom of the secondary air box outputs a "large dust accumulation" signal, the distributed controller immediately starts the dust suction mechanism corresponding to the area.

[0064] As an embodiment provided in this application, Figure 1 to Figure 4 The dust accumulation detection module performs real-time detection of the dust accumulation in each area, and uses the "L1 trend filtering method" to process the data collected by the dust accumulation detection module.

[0065] The dust accumulation detection module installed in the secondary air box transmits the detection data to the distributed controller in real time. Since the secondary air box is a high-temperature, high-dust environment, it may interfere with the normal operation of various types of sensors and cause inaccurate detection results. Therefore, a "data validity" screening module is added to the distributed controller.

[0066] The data collected in this invention is large, and the "L1 trend filtering method" is used to reduce data noise:

[0067] 1. Create a "data bar" with a fixed capacity and length of n to store the data sent by the dust accumulation detection module in real time;

[0068] 2. The newly collected signal data of the dust accumulation detection module are stored in the aforementioned "data strip" in sequence. When the "data strip" is not full, no noise reduction calculation is performed on the data, and the output result is the original value of the dust accumulation detection module.

[0069] 3. When the "data strip" collects n data for the first time, the data strip is full and noise reduction operation starts on the data strip. The specific method is to first perform the first L1 trend filter on the data strip, and the filtering result is output as the last bit of the L1 trend filter;

[0070] 4. After the first filtering operation is completed, the aforementioned data strip is shifted once, the first element is removed, and the following elements are shifted in sequence. The final effect is that the real-time value currently sent by the dust accumulation detection module is the last element of the data strip;

[0071] 5. The dust accumulation detection module continuously inputs new data into the data strip, so that the data strip is updated all the time. After each update, the data strip needs to be subjected to a new L1 trend filter process, and the result of the noise reduction operation is output as the last bit of the L1 trend filter;

[0072] 6. Slide and update the data bars one by one.

[0073] from Figure 3 and Figure 4 It can be seen that after noise reduction processing, the data volatility is reduced and the stability is increased, which is beneficial to improve the accuracy of the analysis and judgment of the dust accumulation in the wind box.

[0074] Here, the following conditions are proposed to determine the amount of ash accumulation: (1) the actual amount of coal fed into the boiler is greater than 10.0 t / h, with a delay of 30 minutes; (2) the signal sent by the sensor (pressure, material level, light, etc.) is greater than the limit value for 10 consecutive minutes after noise reduction processing. If both of the above conditions are met, it is determined that the amount of ash accumulation is large.

[0075] The result of the dust accumulation detection is an important basis for starting and stopping the dust suction device, so the above steps need to be adopted to improve the accuracy of the results.

[0076] As an embodiment provided in this application, Figure 1 and Figure 2 , the primary air duct valve of the primary air duct connected to the air inlet pipe of the ash suction mechanism is opened, and the primary air duct valve of the primary air duct connected to the air outlet pipe of the ash suction mechanism is closed;

[0077] The air inlet valve and ash outlet valve of the ash suction mechanism are opened;

[0078] The hot primary air with high temperature and high pressure inside the primary air duct passes through the air inlet pipe and the ejector to become a high-speed primary air flow. The primary air flow passes through the expander and the air outlet pipe and enters the primary air duct. In this process, the dust is sucked into the expander through the small holes inside the suction port and the ash inlet pipe, and follows the primary air flow through the air outlet pipe into the primary air duct, and is then guided by the primary air duct to be discharged from the secondary air box.

[0079] In the above process, when the high-speed primary air flows through the expansion container and the air outlet pipe, the dust can be sucked into the ash pipe under the jet vacuum effect.

[0080] The distributed controller analyzes and processes the data sent by the dust accumulation detection module. When a certain area is judged to have a "large dust accumulation" condition, the distributed controller will execute the following measures (in Figure 1 and Figure 2 Take the dust blowing in the middle dust suction mechanism area as an example):

[0081]

[0082] It should be pointed out that when the coal mill corresponding to the primary air duct is in normal use, this device does not work. Only when the coal mill stops can the "ash suction-external discharge" operation be implemented with the help of its primary air duct.

[0083] In summary, compared with the existing solutions of "manual cleaning" and "bottom dust blowing with purge air", the present invention has many advantages such as strong initiative, high controllability, high dust removal efficiency, and automatic start and stop, and can achieve the benefits of reducing staff and increasing efficiency. Compared with the existing solutions of "manual cleaning" and "bottom dust blowing with purge air", the present invention makes full use of the existing high-pressure primary air system, and has the advantages of low cost, small engineering modification amount, and short construction period.

[0084] Finally, it should be pointed out that the methods and devices described in detail above are only embodiments, and those skilled in the art can modify these embodiments in different ways without departing from the scope of the present invention.

Claims

1. A secondary air box dust removal device, characterized in that: include, A main body mechanism (1), the main body mechanism (1) comprising a main component (11), and an exhaust component (12) installed outside the main component (11); Wherein, the exhaust components (12) are provided in at least two numbers; An ash suction mechanism (2), the ash suction mechanism (2) comprising a connecting component (21) installed on the outside of the exhaust component (12), and an auxiliary component (22) installed on the outside of the connecting component (21); Wherein, the dust suction mechanism (2) is installed between two adjacent exhaust components (12); A dust accumulation detection module (3), the dust accumulation detection module (3) being used to detect the dust accumulation inside the main component (11); A distributed controller (4), wherein the distributed controller (4) is electrically connected to the exhaust component (12), the dust suction mechanism (2), and the dust accumulation detection module (3).

2. The secondary air box dust removal device according to claim 1 is characterized in that: The main component (11) comprises a secondary air box (111) and an air inlet (112) fixedly connected to the outside of the secondary air box (111).

3. The secondary air box dust removal device according to claim 2 is characterized in that: The exhaust component (12) comprises a primary air duct (121) fixedly connected to the outside of the secondary air box (111), a primary air duct valve (122) adapted to be installed inside the primary air duct (121), and a pulverized coal burner (123) adapted to be installed outside the primary air duct (121).

4. The secondary air box dust removal device according to claim 3 is characterized in that: The connecting component (21) comprises an air intake pipe (211) fixedly connected to the outside of the primary air duct (121), an air intake valve (212) adapted to be installed inside the air intake pipe (211), an ejector (213) adapted to be installed outside the air intake pipe (211), and a nozzle (214) adapted to be installed outside the ejector (213).

5. The secondary air box dust removal device according to claim 4 is characterized in that: The auxiliary component (22) comprises an expansion container (221) fixedly connected to the outside of the air inlet pipe (211), an ash inlet pipe (222) fixedly connected to the outside of the expansion container (221), a suction port (223) fixedly connected to the outside of the ash inlet pipe (222), an air outlet pipe (224) fixedly connected to the outside of the expansion container (221), and an ash outlet valve (225) adapted to be installed inside the air outlet pipe (224); The ejector (213) and the nozzle (214) are arranged inside the expansion container (221), and a small hole is opened on the outside of the suction port (223).

6. The secondary air box dust removal device according to claim 5, characterized in that: The distributed controller (4) is electrically connected to the primary air duct valve (122), the air intake valve (212), the ash discharge valve (225), and the ash accumulation detection module (3).

7. A method of use, characterized in that: A secondary air box dust removal device for use in any one of claims 1 to 6, and The bottom of the secondary air box is divided into areas, and an ash suction mechanism is set in each area; The dust accumulation detection module detects the dust accumulation in each area in real time; When the amount of dust accumulated in a certain area exceeds a preset value, the dust suction mechanism in the area is activated.

8. The method of use according to claim 7, characterized in that: There are n primary air ducts inside the secondary air box, and a dust suction mechanism is set between every two adjacent primary air ducts, that is, n-1 dust suction mechanisms are set; The bottom of the secondary air box is divided into n-1 areas, and an ash suction mechanism is set in each area.

9. The method of use according to claim 8, characterized in that: The dust accumulation detection module performs real-time detection of dust accumulation in each area and uses the "L1 trend filtering method" to process the data collected by the dust accumulation detection module.

10. The method of use according to claim 9, characterized in that: The primary air duct valve of the primary air duct connected to the air inlet pipe of the ash suction mechanism is opened, and the primary air duct valve of the primary air duct connected to the air outlet pipe of the ash suction mechanism is closed; The air inlet valve and ash outlet valve of the ash suction mechanism are opened; The hot primary air with high temperature and high pressure inside the primary air duct passes through the air inlet pipe and the ejector to become a high-speed primary air flow. The primary air flow passes through the expander and the air outlet pipe and enters the primary air duct. In this process, the dust is sucked into the expander through the small holes inside the suction port and the ash inlet pipe, and follows the primary air flow through the air outlet pipe into the primary air duct, and is then guided by the primary air duct to be discharged from the secondary air box.

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