CN104235877B - A kind of pulverized coal firing boiler gas burner and control method thereof - Google Patents

Abstract

The invention discloses a pulverized coal boiler gas burner and its control method, comprising a burner, a primary combustion chamber and a burner control system, characterized in that the burner includes a gas-supporting tube, a hollow tube located in the direction of the burner axis , the air channel, the mixed gas pipe and the pulverized coal air pipe connected with the air of the gas-supporting pipe; the front end of the pulverized coal air pipe is connected to the primary combustion chamber; the rear end of the burner is provided with a natural gas pipe, a gas pipe and a connection between the natural gas pipe and The gas mixing chamber of the gas pipe; the burner control system is electrically connected with the gas-supporting control device, the pulverized coal control device, the natural gas control device, the coal gas control device and the compressed air control device; the advantages of the present invention are: simple and reasonable structure, high ignition efficiency High and stable, prevent combustion wall slagging, ablation, oil-free and gas-saving, and effectively avoid catastrophic accidents.

Description

A pulverized coal boiler gas burner and its control method

technical field

The invention relates to the field of boiler combustion devices, in particular to a pulverized coal boiler gas burner and a control method thereof.

Background technique

At present, when the boiler equipment starts to operate or operates at a very low load, a special oil gun is often used to spray heavy oil into the furnace, a high-energy igniter is used to ignite the fuel oil, and then the fuel oil is ignited to ignite the pulverized coal. Since the ignition starts from the cold furnace state, the ignition efficiency of this method is very high. Not high, huge fuel consumption. In order to achieve the purpose of saving fuel or no oil, research and use burners such as micro-oil, less oil, and plasma. The use of natural gas as the ignition fuel can also achieve the purpose of oil-free. The traditional method of starting and igniting the pulverized coal boiler based on the natural gas burner is: first use the ignition rod to ignite the gas burner, and then use the burner to ignite the coal powder. Natural gas has a high calorific value. Gas, currently the gas consumption of this type of burner is high. Gases with low calorific value, such as blast furnace gas, are by-products in the ironmaking process. They have low calorific value, are easy to coke when burned, and have poor flame stability. However, if they are not utilized, they will cause serious harm to the environment. In addition, when the gas concentration reaches the explosion limit, it is very easy to cause a huge catastrophic accident.

Traditional boiler burners have advance and retreat devices, that is, the system needs to send instructions to extend the oil (gas) gun or ignition rod into the designated area during operation. Such telescopic actions require air drives, travel switches, electromagnetic control valves and other pneumatic components and other accessories. Assisted completion, complex mechanical structure, equipment manufacturing, maintenance, installation, commissioning and other costs are very high.

Therefore, it is very necessary to design an ignition device with simple structure, high ignition efficiency, stable flame, no oil, gas saving and catastrophic accident prevention.

Contents of the invention

In order to solve the deficiencies of existing pulverized coal boiler burners, the object of the present invention is to provide a pulverized coal boiler gas burner and its control method, which can save high calorific value gas by burning the mixed gas of natural gas and low calorific value gas, and prevent condensation Slag, simple structure, high ignition efficiency, stable flame.

In order to achieve the above object, the present invention adopts the following technical solution: a pulverized coal boiler gas burner and its control method, including a burner, a primary combustion chamber and a burner control system, characterized in that: the burner includes a connecting The gas-supporting tube on the outer wall of the burner, the hollow tube located in the axial direction of the burner, the air channel located outside the hollow tube in wind communication with the gas-supporting tube, the mixed gas tube located outside the air channel, and the gas-supporting tube located outside the air channel. The pulverized coal air pipe outside the mixed gas pipe; the front end of the pulverized coal air pipe is connected to the primary combustion chamber; the rear end of the burner is provided with a natural gas pipe, a gas pipe, and a gas pipe connected The gas mixing chamber; the burner control system and the gas-supporting control device located at the inlet end of the gas-supporting pipe, the pulverized coal control device located at the inlet end of the pulverized coal air pipe, the natural gas control device located at the inlet end of the natural gas pipe, and the The gas control device at the inlet end of the gas pipe is electrically connected to the compressed air control device at the inlet end of the compressed air pipe.

The aforementioned gas burner for a pulverized coal boiler is characterized in that: the mixed gas pipe includes a rear end of the mixed gas pipe communicated with the gas mixing chamber, a front end of the mixed gas pipe communicated with the rear end of the mixed gas pipe, The inner diameter of the front end of the mixed gas pipe is smaller than the inner diameter of the rear end of the mixed gas pipe.

The aforementioned gas burner for a pulverized coal boiler is characterized in that: a support rod is provided between the outer wall of the burner and the pulverized coal air duct inside the burner.

The aforementioned pulverized coal boiler gas burner is characterized in that: the front end of the pulverized coal air pipe in the burner is provided with a pulverized coal concentrating pipe, and the rear end of the pulverized coal concentrating pipe is provided with a pulverized coal concentrating device.

The aforementioned gas burner for a pulverized coal boiler is characterized in that: the front end of the air channel is provided with a flashback preventer, and the flashback preventer is a metal wire ball or a metal plate with gaps superimposed on each other.

The aforementioned gas burner for a pulverized coal boiler is characterized in that: the first-stage combustion chamber, the front end of the pulverized coal air duct located in the burner, and the pulverized coal concentration pipe are provided with hollow double walls, forming a concave shape The air cavity is provided with several air holes on the inner wall; the compressed air pipe is arranged outside the first-stage combustion chamber.

The aforementioned gas burner for a pulverized coal boiler is characterized in that: the natural gas control device and the gas control device respectively include a flow meter, a flow regulating valve, a manual shut-off valve, an electric ball valve, an emptying valve and a flame arrester connected in sequence , the flow meter, the flow regulating valve, the electric ball valve and the exhaust valve are respectively electrically connected to the burner control system.

The aforementioned gas burner for a pulverized coal boiler is characterized in that: the pulverized coal control device, the gas-supporting control device and the compressed air control device respectively include a manual shut-off valve and an electric ball valve, and the electric ball valve is connected to the combustion chamber respectively. electrical connection to the controller control system.

The aforementioned gas burner for a pulverized coal boiler is characterized in that: the front end of the mixed gas pipe is provided with a number of mixed gas outlet holes.

The aforementioned gas burner for a pulverized coal boiler is characterized in that: an igniter electrically connected to the burner control system is placed in the hollow tube; a flame detection device is placed on the side of the hollow tube close to the flame, and the flame detection device Electrically connected to the burner control system.

A method for controlling a pulverized coal boiler gas burner, comprising:

The burner control system automatically controls the opening of the gas-supporting pipe, and uses the air in the gas-supporting pipe to purge the burner and the primary combustion chamber to exhaust the mixed gas;

When igniting, the burner control system automatically controls to open the pulverized coal air pipe, natural gas pipe and gas pipe, and controls the igniter in the hollow pipe to ignite the mixed gas;

The flame condition is monitored by the flame detection device. When the flame is small, the burner control system respectively controls the flow regulating valve to increase the flow of natural gas, reduces the flow of gas with low calorific value, and stabilizes the flame; when the flame is stable, controls the flow regulating valve to reduce the flow of natural gas. Increase the flow of gas with low calorific value; when the combustion flame is extinguished, automatically control the electric ball valve of the natural gas control device and the gas control device to close the gas pipeline;

When it is necessary to overhaul the gas pipeline, use the exhaust valve in the pipeline to drain the remaining gas in the pipeline.

The above-mentioned control method for the gas burner of a pulverized coal boiler is characterized in that the compressed air control device is automatically controlled by the burner control system, the compressed air pipe is opened regularly, and the front end of the burner and a burner are cleared through the compressed air and the concave-shaped air cavity. Slagging on the inner wall of the combustion stage.

The beneficial effects achieved by the present invention: use the mixed gas of natural gas with high calorific value and coal gas with low calorific value as fuel gas, set an igniter in the hollow tube to ignite the gas, then ignite the pulverized coal in the concentrating tube, and then ignite the pulverized coal in the primary combustion chamber ; Use the flame observation device to detect the flame intensity in real time, and adjust the gas flow through the burner control system; prevent slagging through the concave-shaped air cavity and compressed air pipe. The invention has simple and reasonable structure, high and stable ignition efficiency, prevents slagging and ablation of the combustion wall, saves oil and gas, and effectively avoids catastrophic accidents.

Description of drawings

Fig. 1 is the structural representation of this burner;

Fig. 2 is a schematic cross-sectional view of the burner head;

Fig. 3 is a schematic cross-sectional view of the rear end of the burner;

Meanings of reference signs in the figure:

1-Burner, 2-Primary combustion chamber, 3-Burner control system, 4-Auxiliary gas pipe, 5-Powdered coal air pipe, 6-Rear end of mixed gas pipe, 7-Front end of mixed gas pipe, 8-Hollow Pipe, 9-flame preventer, 10 support rod, 11-compressed air pipe, 12-concave air chamber, 13-coal powder concentration device, 14-natural gas pipe, 15-gas pipe, 16-natural gas control device, 17 -gas control device, 18-coal pulverized control device, 19-supporting gas control device, 20-air channel, 21 pulverized coal concentration pipe, 22-burner outer wall, 23-gas mixing chamber, 24-mixed gas outlet, 25 -Compressed air controls.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solutions of the present invention more clearly, but not to limit the protection scope of the present invention.

A pulverized coal boiler gas burner, comprising a burner 1, a primary combustion chamber 2 and a burner control system 3.

As shown in Figure 1, the burner 1 includes a gas-supporting pipe 4 connected to the outer wall 22 of the burner, a hollow pipe 8 located in the axial direction of the burner 1, and an air channel 20 located outside the hollow pipe 8 and communicating with the gas-supporting pipe 4. , the mixed gas pipe positioned outside the air channel 20 and the pulverized coal air pipe 5 outside the mixed gas pipe; the front end of the pulverized coal air pipe 5 is connected to the primary combustion chamber 2; the rear end of the burner 1 is provided with a natural gas pipe 14, a gas pipe 15 and the gas mixing chamber 23 that connects the natural gas pipe 14 and the gas pipe 15;

The mixed gas pipe includes a mixed gas pipe rear end 6 communicated with the gas mixing chamber 23 and a mixed gas pipe front end 7 communicated with the mixed gas pipe rear end 6. The inner diameter of the mixed gas pipe front end 7 is smaller than the mixed gas pipe rear end 6 inner diameter.

A support rod 10 is provided between the outer wall 22 of the burner and the pulverized coal air pipe 5 inside the burner.

The front end of the pulverized coal air pipe 5 in the burner is provided with a pulverized coal concentrator pipe 21, and the rear end of the pulverized coal concentrator pipe 21 is provided with a pulverized coal concentrator 13, and the pulverized coal concentrator 13 plays a role of supporting and fixing at the same time.

The front end of the air channel 2 is provided with a flashback preventer 9, and the flashback preventer 9 is a metal wire ball or a metal plate with gaps superimposed on each other, as shown in FIG. 2 .

The primary combustion chamber 2, the front end of the pulverized coal air pipe 5 in the burner and the pulverized coal concentration pipe 21 are provided with a hollow double wall, and the middle part of the pulverized coal air pipe 5 in the burner is connected with the pulverized coal concentration pipe 21. The rear end of 21 is provided with a trachea communicating with the above-mentioned hollow double wall, the above-mentioned double wall and trachea form a concave-shaped air cavity 12, and a number of air holes are provided on the inner wall, and the diameter of the air holes is 20 microns to 1 mm. Larger particles can be prevented from falling into the inner wall, and a compressed air pipe 11 is provided outside the primary combustion chamber 2 .

The front end of the mixed gas pipe is provided with a number of mixed gas outlets 24 on the outer surface of the front end of the mixed gas pipe, and the air holes are evenly distributed at the front end of the mixed gas pipe, as shown in FIG. 2 .

The hollow tube 8 is provided with an igniter electrically connected to the burner control system 3. The igniter can be placed directly in the hollow tube without complicated telescopic mechanism. Since the igniter is not directly in the high-temperature combustion zone, the igniter is not easy to burn. It is ablated, and the structure is simplified; the flame detection device is placed on the side of the hollow tube 8 near the flame, and the flame detection device is electrically connected with the burner control system 3 .

Fig. 3 is a schematic cross-sectional view of the rear end of the burner 1, which is helpful for a better understanding of the internal structure of the burner.

The burner control system 3 and the gas-supporting control device 19 located at the inlet end of the gas-supporting pipe 4, the pulverized coal control device 18 located at the inlet end of the pulverized coal air pipe 5, the natural gas control device 16 located at the inlet end of the natural gas pipe 14, and the coal gas at the inlet end of the gas pipe 15 The control device 17 is electrically connected with the compressed air control device 25 located at the inlet end of the compressed air pipe 11 .

The natural gas control device 16 and the gas control device 17 respectively comprise a flow meter, a flow regulating valve, a manual shut-off valve, an electric ball valve, an emptying valve and a flame arrester connected in sequence, and the flow meter, a flow regulating valve, an electric ball valve and an emptying valve The valves are respectively electrically connected with the burner control system 3 . The manual shut-off valve is used for manual control, which can double guarantee to quickly cut off the gas supply in emergency situations, and can also be used for manual maintenance and other situations. A filtering device is also provided at the inlet of the natural gas and coal gas control device to filter out impurities in the natural gas and coal gas, so as to prevent from blocking the mixed gas outlet hole 24 of the burner and affecting combustion instability. The rated flow rate before the gas enters the control device is 3.3×10 ⁴ Nm ³ /h, the temperature is 3°-36°, and the pressure is 0.35Mpa. The flow regulating valve is used to adjust the gas flow entering the mixed gas pipe; the exhaust valve is used to Exhaust the remaining gas in the burner tube for easy maintenance.

The pulverized coal control device 18 , the assisted gas control device 19 and the compressed air control device 25 respectively include a manual shut-off valve and an electric ball valve, and the electric ball valves are respectively electrically connected to the burner control system 3 .

Control method of pulverized coal boiler gas burner:

The burner control system 3 automatically controls to open the gas-supporting pipe 4, and uses the air in the gas-supporting pipe 4 to purge the burner 1 and the primary combustion chamber 2, and discharge the mixed gas therein;

When igniting, the burner control system 3 automatically controls to open the pulverized coal air pipe 5, the natural gas pipe 14 and the gas pipe 15, and controls the igniter in the hollow pipe 8 to ignite the mixed gas;

The flame condition is monitored by the flame detection device. When the flame is small, the burner control system 3 respectively controls the flow regulating valve to increase the flow of natural gas, reduces the flow of gas with low calorific value, and stabilizes the flame; when the flame is stable, controls the flow regulating valve to reduce the flow of natural gas , increase the gas flow rate of low calorific value; when the combustion flame is extinguished, the electric ball valves of the natural gas control device 16 and the gas control device 17 are automatically controlled to close the gas pipeline, which can effectively avoid catastrophic accidents.

When it is necessary to overhaul the gas pipeline, use the exhaust valve in the pipeline to drain the remaining gas in the pipeline.

The compressed air control device 25 is automatically controlled by the burner control system 3, the compressed air pipe 11 is opened regularly, and the slagging on the front end of the burner 1 and the inner wall of the primary combustion chamber 2 is removed by using the compressed air and the concave-shaped air cavity 12.

Use the mixed gas of natural gas with high calorific value and coal gas with low calorific value as fuel gas to effectively consume low calorific value gas, save natural gas consumption, and ensure the stability of the flame; set an igniter in the hollow tube to ignite the gas, and then ignite the coal in the concentration tube Then ignite the pulverized coal in the primary combustion chamber; use the flame observation device to detect the flame intensity in real time, and adjust the gas flow through the burner control system; prevent slagging through the concave-shaped air cavity and compressed air pipe. The invention has simple and reasonable structure, high and stable ignition efficiency, prevents slagging and ablation of the combustion wall, saves oil and gas, and effectively avoids catastrophic accidents.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and modifications can also be made. It should also be regarded as the protection scope of the present invention.

Claims (11)

1. A pulverized coal boiler gas burner, comprising a burner (1), a primary combustion chamber (2) and a burner control system (3), characterized in that: the burner (1) includes a burner connected to the burner The gas-supporting pipe (4) on the outer wall (22), the hollow tube (8) located in the axial direction of the burner (1), the air located outside the hollow tube (8) and in wind communication with the gas-supporting pipe (4) passage (20), the mixed gas pipe positioned outside the air passage (20) and the pulverized coal air pipe (5) located outside the mixed gas pipe; the front end of the pulverized coal air pipe (5) is connected to the one stage combustion chamber (2); the rear end of the burner (1) is provided with a natural gas pipe (14), a gas pipe (15) and a gas mixing chamber ( 23); the burner control system (3) and the gas-supporting control device (19) at the inlet end of the gas-supporting pipe (4) and the pulverized coal control device (18) at the inlet end of the pulverized coal air pipe (5) , a natural gas control device (16) positioned at the inlet of the natural gas pipe (14), a gas control device (17) positioned at the inlet of the gas pipe (15) and a compressed air control device (25) positioned at the inlet of the compressed air pipe (11) ) electrical connection; said hollow tube (8) is provided with an igniter electrically connected to the burner control system (3); said hollow tube (8) places a flame detection device on the flame side, and said flame detection The device is electrically connected with the burner control system (3); the compressed air pipe (11) is located on the outer wall of the primary combustion chamber (2); the gas mixing chamber (23) communicates with the mixed gas pipe. 2. A pulverized coal boiler gas burner according to claim 1, characterized in that: the mixed gas pipe includes a rear end (6) of the mixed gas pipe communicated with the gas mixing chamber (23), connected to the The front end (7) of the mixed gas pipe connected to the rear end (6) of the mixed gas pipe, the inner diameter of the front end (7) of the mixed gas pipe is smaller than the inner diameter of the rear end (6) of the mixed gas pipe. 3. A pulverized coal boiler gas burner according to claim 1, characterized in that: a support is provided between the outer wall of the burner (22) and the pulverized coal air pipe (5) in the burner Rod (10). 4. A pulverized coal boiler gas burner according to claim 1, characterized in that: the front end of the pulverized coal air duct (5) in the burner is provided with a pulverized coal concentration pipe (21), and the pulverized coal The rear end of the powder concentration pipe (21) is provided with a coal powder concentration device (13). 5. A pulverized coal boiler gas burner according to claim 2, characterized in that: the front end of the air channel (20) is provided with a flashback preventer (9), and the flashback preventer (9) is Balls of wire or metal plates superimposed on each other with gaps. 6. A gas burner for a pulverized coal boiler according to claim 1, characterized in that: the primary combustion chamber (2), the front end of the pulverized coal air pipe (5) located in the burner and the pulverized coal concentration The tube (21) is provided with a hollow double wall to form a concave-shaped air cavity (12), and a number of air holes are provided on the inner wall; a compressed air tube (11) is provided outside the primary combustion chamber (2). 7. A pulverized coal boiler gas burner according to claim 1, characterized in that: the natural gas control device (16) and the gas control device (17) respectively include a flow meter, a flow regulating valve, a manual A shut-off valve, an electric ball valve, an emptying valve and a flame arrester, the flowmeter, the flow regulating valve, the electric ball valve and the emptying valve are respectively electrically connected to the burner control system (3). 8. A pulverized coal boiler gas burner according to claim 1, characterized in that: the pulverized coal control device (18), the combustion gas control device (19) and the compressed air control device (25) respectively include manual A shut-off valve and an electric ball valve are respectively electrically connected to the burner control system (3). 9. A gas burner for a pulverized coal boiler according to claim 1, characterized in that: a number of mixed gas outlet holes (24) are provided on the periphery of the front end of the mixed gas pipe. 10. A control method for a pulverized coal boiler gas burner, comprising: The burner control system (3) automatically controls to open the gas-supporting pipe (4), and uses the air in the gas-supporting pipe (4) to purge the burner (1) and the primary combustion chamber (2), and discharge the mixed gas therein; When igniting, the burner control system (3) automatically controls to open the pulverized coal air pipe (5), the natural gas pipe (14) and the gas pipe (15), and controls the igniter in the hollow pipe (8) to ignite the mixed gas; The flame condition is monitored by the flame detection device. When the flame is small, the burner control system (3) respectively controls the flow regulating valve to increase the natural gas flow, reduces the low calorific value gas flow, and stabilizes the flame; when the flame is stable, controls the flow regulating valve to decrease Natural gas flow, increase the low heat value gas flow; when the combustion flame is extinguished, automatically control the electric ball valve of the natural gas control device (16) and the gas control device (17) to close the gas pipeline; When it is necessary to overhaul the gas pipeline, use the exhaust valve in the pipeline to drain the remaining gas in the pipeline. 11. A method for controlling the gas burner of a pulverized coal boiler according to claim 10, characterized in that the compressed air control device (25) is automatically controlled by the burner control system (3), and the compressed air pipe (11) is opened at regular intervals ), remove the slagging on the front end of the burner (1) and the inner wall of the primary combustion chamber (2) by compressed air and the concave-shaped air cavity (12).