Coal combustion unit 20% load combustion device

Abstract

The invention discloses a coal-fired unit 20% load combustion device, which belongs to the technical field of coal-fired boiler power generation, and comprises a boiler, a primary pulverized coal pipe, a cyclone separator, a pulverized coal bunker and a gasifier, a main combustion area and a stable combustion area are arranged in the boiler, a plurality of superheaters are arranged at the top end in the boiler, the primary pulverized coal pipe is communicated with the main combustion area, and the cyclone separator is communicated with the pulverized coal bunker. A branch pipeline is arranged on the primary air powder pipe, the branch pipeline is communicated with the cyclone separator, and a stop valve is arranged on the branch pipeline; the cyclone separator is communicated with the pulverized coal bunker, the output end of the superheater is provided with a steam pipeline, the steam pipeline is communicated with the pulverized coal bunker, the pulverized coal bunker is communicated with the gasification furnace, and the gasification furnace is communicated with the stable combustion area. When a coal-fired unit operates at a low load, part of pulverized coal is subjected to gas-solid separation and further levigation, the levigated pulverized coal is blown into the gasification furnace to be gasified through high-temperature steam output by the superheater, then generated coal gas is introduced into the stable combustion area to be stably combusted, economy and energy conservation are achieved, the burn-off rate of the pulverized coal is high, and the requirement for ultra-low load peak regulation is met.

Description

Technical Field

[0001] The invention belongs to the technical field of coal-fired boiler power generation, and in particular relates to a 20% load combustion device for a coal-fired unit. Background Art

[0002] Coal-fired power generation is still an important source of electricity in my country's power supply system. Coal-fired power plants still use a large number of pulverized coal-fired boiler power generation devices, which are in a state of low-load operation. When coal-fired units are operating at low loads for deep peak regulation, the amount of pulverized coal in the boiler is greatly reduced, the air-to-coal ratio increases greatly, and the relative heat release of coal is greatly reduced, which will cause the furnace temperature to drop, the flame burning stability to decrease, and the boiler to be easily extinguished. It is difficult to maintain stable combustion by simply adjusting the boiler operating parameters; and when operating at low load, its operating parameters will deviate greatly from the design parameters, resulting in a decrease in the thermal efficiency of the unit, thereby increasing coal consumption.

[0003] In the prior art, the stability of low-load combustion of the boiler can be improved by adding auxiliary combustion oil or gas, but this will increase fuel costs. It is urgent for technical personnel in this field to propose an economical, energy-saving device that can enable the boiler to operate stably at 20% load. Summary of the invention

[0004] In view of this, the present invention provides a 20% load combustion device for a coal-fired unit to solve the above problems.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A 20% load combustion device for a coal-fired unit comprises: a boiler, a primary air powder pipe, a cyclone separator, a pulverized coal bin and a gasifier, wherein a main combustion zone and a stable combustion zone are arranged in the boiler, a plurality of superheaters are arranged at the top of the boiler, the primary air powder pipe is connected to the main combustion zone, a branch pipeline is arranged on the primary air powder pipe, the branch pipeline is connected to the cyclone separator, and a stop valve is arranged on the branch pipeline; the cyclone separator is connected to the pulverized coal bin, a steam pipeline is arranged at the output end of the superheater, the steam pipeline is connected to the pulverized coal bin, the pulverized coal bin is connected to the gasifier, and the gasifier is connected to the stable combustion zone.

[0007] Furthermore, the stable combustion zone is located above the main combustion zone, and the connection port between the gasifier and the stable combustion zone on the boiler is higher than the connection port between the primary air powder pipe and the main combustion zone on the boiler.

[0008] Furthermore, an ultrafine coal mill is provided between the cyclone separator and the pulverized coal bin for further pulverizing the pulverized coal.

[0009] Furthermore, a steam tank is provided on the steam pipeline for increasing the steam pressure for blowing the pulverized coal from the pulverized coal bin into the gasifier.

[0010] Furthermore, an auxiliary steam generating device is provided, and the auxiliary steam generating device is communicated with the pulverized coal bin.

[0011] Furthermore, an igniter is provided in the gasifier, and is located on one side of the communication port between the pulverized coal bin and the gasifier.

[0012] The beneficial effects of the present invention are:

[0013] When the coal-fired unit is running at a low load, the stop valve on the branch pipeline is opened, and a part of the pulverized coal is introduced into the main combustion zone of the boiler through the primary air-powder pipe, and the other part enters the pulverized coal bin after gas-solid separation and ultra-fine grinding of the pulverized coal. The superheater at the top of the boiler is further pressurized by the steam tank, and the pulverized coal in the pulverized coal bin is blown into the gasification furnace. The high-temperature steam and the ground pulverized coal react with the help of the igniter to generate coal gas, and the coal gas enters the stable combustion zone as an auxiliary fuel for stable combustion, thereby avoiding the use of other auxiliary fuels with higher costs. This is economical and energy-saving, improves the burnout rate of the pulverized coal, and enables the boiler to operate stably at a load of 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0015] Figure 1 It is a schematic diagram of a 20% load combustion device of a coal-fired unit;

[0016] Among them, in the figure:

[0017] 10-boiler, 11-main combustion zone, 12-stable combustion zone, 13-superheater, 131-steam pipeline, 20-primary air powder pipe, 21-branch pipeline, 211-stop valve, 30-cyclone separator, 40-coal powder bin, 50-gasifier, 60-ultrafine coal mill, 70-steam tank, 80-auxiliary steam generator, 90-igniter. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] See attached Figure 1 As shown, the present invention provides a 20% load combustion device for a coal-fired unit, comprising: a boiler 10, a primary air powder pipe 20, a cyclone separator 30, a pulverized coal bin 40 and a gasifier 50. The boiler 10 is provided with a main combustion zone 11 and a stable combustion zone 12. The main combustion zone 11 is used to burn pulverized coal, and the stable combustion zone 12 is used to burn coal gas after the pulverized coal is gasified. A plurality of superheaters 13 are provided at the top of the boiler 10. The primary air powder pipe 20 is connected to the main combustion zone 11. A branch pipeline 21 is provided on the primary air powder pipe 20. The branch pipeline 21 is connected to the cyclone separator 30. The pulverized coal in the primary air powder pipe 20 enters the cyclone separator. 30 performs gas-solid separation to obtain pulverized coal; a stop valve 211 is provided on the branch pipeline 21; the cyclone separator 30 is connected to the pulverized coal bin 40, and the output end of the last-stage superheater 13 among the multiple superheaters 13 is provided with a steam pipeline 131, the steam pipeline 131 is connected to the pulverized coal bin 40, the pulverized coal bin 40 is connected to the gasifier 50, and the gasifier 50 is connected to the stable combustion zone 12, and the high-temperature fuel gas output from the superheater 13 passes through the steam pipeline 131 to blow the pulverized coal in the pulverized coal bin 40 into the gasifier 50 for gasification, and coal gas is obtained in the gasifier 50, and the coal gas enters the stable combustion zone 12 of the boiler 10 for stable combustion.

[0020] In a preferred embodiment, the stable combustion zone 12 is located above the main combustion zone 11, and the connection port between the gasifier 50 and the stable combustion zone 12 on the boiler 10 is higher than the connection port between the primary air powder pipe 20 and the main combustion zone 11 on the boiler 10. The pulverized coal in the main combustion zone 11 burns and heats the superheater 13, and at the same time ignites the coal gas entering the stable combustion zone 12 above, and further burns in the boiler 10 for stable combustion.

[0021] In a preferred embodiment, an ultrafine coal mill 60 is provided between the cyclone separator 30 and the coal powder bin 40 for further grinding the coal powder. The coal powder is further ground and then enters the gasifier 50, thereby increasing the contact area with the high-temperature steam and facilitating the gasification reaction of the coal powder.

[0022] In a preferred embodiment, a steam tank 70 is provided on the steam pipeline 131 for increasing the steam pressure for blowing the pulverized coal from the pulverized coal bin 40 into the gasifier 50 , so that the pulverized coal and high-temperature steam undergo a sufficient gasification reaction in the gasifier 50 .

[0023] In a preferred embodiment, a 20% load combustion device of a coal-fired unit is further provided with an auxiliary steam generating device 80 , which is connected to the pulverized coal bin 40 . The auxiliary steam generating device 80 is a steam drum or other steam generating device, which is a supplement to the high-temperature steam generated by the superheater 13 .

[0024] In a preferred embodiment, an igniter 90 is provided in the gasifier 50, and is located at one side of the connection between the pulverized coal bin 40 and the gasifier 50. Pulverized coal and water vapor can react to produce coal gas at high temperature, and the igniter 90 helps to further improve the efficiency of the gasification reaction.

[0025] Working principle: When the coal-fired unit is running at low load, the stop valve 211 on the branch pipeline 21 is opened, and a part of the coal powder is passed into the main combustion zone 11 of the boiler 10 through the primary air powder pipe 20 for combustion, and the other part of the coal powder enters the cyclone separator 30 for gas-solid separation to obtain coal powder; the coal powder enters the ultra-fine coal mill 60 for further grinding, and the further ground coal powder enters the coal powder bin 40; the superheater 13 at the top of the boiler 10 is further pressurized by the steam tank 70, and the coal powder in the coal powder bin 40 is blown into the gasification furnace 50, and the high-temperature water vapor and the ground coal powder react with the help of the igniter 90 to produce coal gas, and the coal gas enters the stable combustion zone 12 as an auxiliary fuel for stable combustion.

[0026] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0027] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A 20% load combustion device for a coal-fired unit, characterized in that: include: A boiler (10), a primary air powder pipe (20), a cyclone separator (30), a pulverized coal bin (40) and a gasifier (50), wherein the boiler (10) is provided with a main combustion zone (11) and a stable combustion zone (12), a plurality of superheaters (13) are provided at the top of the boiler (10), the primary air powder pipe (20) is connected to the main combustion zone (11), a branch pipeline (21) is provided on the primary air powder pipe (20), and the branch pipeline (21) is connected to the main combustion zone (11). The cyclone separator (30) is connected to the pulverized coal bin (40), and a stop valve (211) is provided on the branch pipeline (21); the cyclone separator (30) is connected to the pulverized coal bin (40), and a steam pipeline (131) is provided at the output end of the superheater (13), and the steam pipeline (131) is connected to the pulverized coal bin (40), and the pulverized coal bin (40) is connected to the gasifier (50), and the gasifier (50) is connected to the stable combustion zone (12).

2. A 20% load combustion device for a coal-fired unit according to claim 1, characterized in that: The stable combustion zone (12) is located above the main combustion zone (11), and the connection port between the gasifier (50) and the stable combustion zone (12) on the boiler (10) is higher than the connection port between the primary air powder pipe (20) and the main combustion zone (11) on the boiler (10).

3. A 20% load combustion device for a coal-fired unit according to claim 1, characterized in that: An ultrafine coal mill (60) is provided between the cyclone separator (30) and the pulverized coal bin (40) for further pulverizing the pulverized coal.

4. A 20% load combustion device for a coal-fired unit according to claim 1, characterized in that: The steam pipeline (131) is provided with a steam tank (70) for increasing the steam pressure for blowing pulverized coal from the pulverized coal bin (40) into the gasifier (50).

5. A 20% load combustion device for a coal-fired unit according to claim 1, characterized in that: An auxiliary steam generating device (80) is also provided, and the auxiliary steam generating device (80) is in communication with the pulverized coal bin (40).

6. A 20% load combustion device for a coal-fired unit according to claim 1, characterized in that: An igniter (90) is provided in the gasifier (50) and is located on one side of the communication port between the pulverized coal bin (40) and the gasifier (50).

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