Device for improving combustion efficiency of large coal-fired boiler by blending gas

Abstract

The utility model discloses a device of mixedly burning gas to improve combustion efficiency of large coal-fired boiler belongs to electric power boiler combustion field. The utility model discloses to the problem that the high carbon content of fly ash of large coal-fired boiler mixedly burns gas reformation leads to the problem of boiler efficiency reduction, through the reformation of the four corner tangential burner of boiler, sets up a group of wall type combustor with the vertical arrangement of water cooling wall in the four corner tangential burner bottom water cooling wall four -sided wall, four groups of wall type combustor are on the same horizontal plane, and the hot air pipeline and gas pipeline are configured simultaneously, and set up flame detection device in the combustor, and four groups of wall type combustor cooperate with the four corner tangential burner of upper layer and middle layer simultaneously, and different mixedly burning conditions are responded respectively. The utility model guarantees the equipment operation stability of boiler under various coal mixedly burning gas proportion conditions, improves the boiler combustion efficiency.

Description

Technical Field

[0001] This utility model relates to a device for improving the combustion efficiency of a large coal-fired boiler by co-firing coal gas, belonging to the field of electric boiler combustion. Background Technology

[0002] In the tangential combustion mode of a coal-fired boiler, the burners are arranged at the four corners of the furnace, and the four streams of air flow form an imaginary circle in the center of the furnace. The fuel is injected tangentially into the furnace from the four corners.

[0003] An analysis of the combustion mode of a mixed-fuel boiler after its modification by co-firing blast furnace gas in a coal-fired boiler reveals that the co-firing of large amounts of blast furnace gas results in a large influx of cold gas into the furnace, leading to a decrease in boiler burnout rate, an increase in fly ash carbon content, and a decline in boiler efficiency. The main reasons are as follows: ① Because blast furnace gas is a low-calorific-value fuel, its theoretical combustion temperature is significantly lower than that of pulverized coal. The co-firing of blast furnace gas significantly lowers the furnace temperature, while the actual burnout rate of pulverized coal decreases as the furnace temperature decreases. ② The co-firing of blast furnace gas reduces the oxygen concentration around the pulverized coal, thus slowing down the burnout rate and hindering complete combustion. ③ The large amount of co-firing of blast furnace gas leads to air competition between pulverized coal and blast furnace gas in the initial combustion stage, and simultaneously deteriorates the aerodynamic field within the furnace, further hindering pulverized coal burnout.

[0004] In summary, existing pulverized coal tangential burners, such as gas burners, all adopt a four-corner arrangement, resulting in a significant reduction in boiler efficiency. Therefore, improving the combustion efficiency of large boilers after co-firing with gas, and ensuring the safety and economy of the unit, is particularly important. Utility Model Content

[0005] To address the problem that the original four-corner arrangement of gas burners in coal-fired boilers cannot guarantee boiler efficiency after co-firing with coal gas, this utility model provides a device for improving combustion efficiency in large coal-fired boilers by co-firing with coal gas. The device modifies the bottom four-corner tangential burners, changing them from four-corner tangential burners to a four-wall arrangement, thus solving the problem of air rushing during coal gas combustion. At the same time, it works in conjunction with the original four-corner tangential burners to cope with different co-firing conditions, enabling the boiler to provide combustion efficiency and equipment operation stability under coal-coated coal gas co-firing conditions.

[0006] The technical solution adopted in this utility model is: A device for improving combustion efficiency by co-firing coal gas in a large coal-fired boiler includes 12 coal gas burners arranged in three layers: upper, middle, and lower. The upper and middle layers are arranged with tangentially rounded coal gas burners at the corners, while the bottom layer consists of four sets of wall-mounted burners located in the middle of the four walls of the boiler's water-cooled wall. The four sets of wall-mounted burners are arranged on a horizontal plane, perpendicular to the water-cooled wall. They work in conjunction with the tangentially rounded burners in the upper and middle layers to handle different co-firing conditions.

[0007] Furthermore, the right side of the wall-mounted burner is connected to a gas pipeline, and the left side is connected to a secondary air pipeline.

[0008] Furthermore, a flame detection sleeve is pre-embedded inside the wall-mounted burner for arranging a flame detection device.

[0009] Furthermore, the four sets of wall-mounted burners are supported and fixed by water-cooled walls and rigid beams, and are flexibly connected to other pipelines to ensure sufficient expansion capacity.

[0010] This utility model provides a device for improving combustion efficiency in large coal-fired boilers by co-firing coal gas, which brings the following beneficial effects: (1) When coal-fired boilers are mixed with coal gas, the horizontally arranged coal gas burners are far away from the pulverized coal burners and have separate hot air distribution. The coal gas combustion will not compete for the oxygen required for pulverized coal combustion, ensuring that there is a sufficient oxygen supply for pulverized coal combustion and that it can be completely burned. The carbon content of boiler fly ash is greatly reduced, and the boiler combustion efficiency is improved. (2) When coal-fired boilers are mixed with coal gas, since the coal gas burner is far away from the pulverized coal burner, a large amount of cold coal gas will not affect the high temperature flue gas near the pulverized coal entrainment nozzle to quickly reach the ignition point, thus ensuring the rapid ignition of the pulverized coal. (3) The gas burners are arranged in three layers. When the amount of gas is small, only the upper gas burner can be put into operation. The amount of flue gas in the pulverized coal combustion zone will be reduced, and the residence time of pulverized coal in the combustion zone will be extended, which is conducive to complete combustion. (4) At the same time, this arrangement method has a relatively small scouring effect on the boiler furnace wall. In combination with the original four-corner tangential burner, the three-layer gas burner can adapt to different gas co-firing conditions, so that the boiler combustion efficiency can be guaranteed to be stable under each condition, and the safety and economy of unit operation are improved.

[0011] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0012] Figure 1 This utility model provides a device for improving the combustion efficiency of a large coal-fired boiler by co-firing coal gas. Figure 2 This is a plan view of the four sets of wall-mounted burners; Figure 3 Diagram showing the secondary air and gas layout for the gas burner; Figure 4 Layout diagram of the flame detection device (along) Figure 3 (Section of line AA in the middle).

[0013] In the diagram: 1 is a tangentially shaped gas burner, 2 is a wall-mounted burner, 3 is a secondary air duct, 4 is a gas duct, and 5 is a flame detector sleeve. Detailed Implementation

[0014] Example

[0015] The original gas burner configuration in the boiler consisted of 12 tangentially arranged gas burners in three layers. After co-firing coal gas into the coal-fired boiler, the original tangentially arranged gas burners could no longer guarantee the boiler's combustion efficiency. This invention provides a device for improving the combustion efficiency of large coal-fired boilers by co-firing coal gas, which modifies the original tangentially arranged gas burners, such as... Figure 1 As shown (top view): A device for improving combustion efficiency in a large coal-fired boiler by co-firing with coal gas includes 12 gas burners arranged in three layers: upper, middle, and lower. The upper and middle layers are arranged with tangentially rounded gas burners 1, while the lower layer is modified from tangentially rounded burners to four sets of wall-mounted burners 2, which solves the problem of air rushing during coal gas combustion. At the same time, in conjunction with the tangentially rounded burners in the upper and middle layers, the device can handle different co-firing conditions, ensuring the boiler's combustion efficiency and equipment operational stability under coal-fired gas co-firing conditions.

[0016] The preferred structure is that the four sets of wall-mounted burners 2, arranged at the bottom, are located in the middle of the four walls of the boiler water-cooled wall. The four sets of wall-mounted burners are arranged on a horizontal plane, perpendicular to the water-cooled wall. Figure 2 As shown.

[0017] Furthermore, the right side of the wall-mounted burner 2 is connected to the gas pipeline 4, and the left side is connected to the secondary air pipeline 3.

[0018] Furthermore, a flame detection sleeve 5 is pre-embedded inside the wall-mounted burner for arranging a flame detection device.

[0019] This combustion device is equipped with high-pressure coke oven gas nozzles and air ducts, a gas combustion device air duct (secondary air), a gas combustion assembly, an explosion-proof air damper with an electric actuator at the combustion device inlet, a primary air nozzle, a removable primary air duct (the primary air nozzle and duct can be completely removed from the furnace during maintenance), a secondary air nozzle, a gas burner fixing device, a gas flame detector for real-time monitoring of boiler combustion conditions, and a single-layer gas ignition system using coke oven gas as ignition fuel.

[0020] Furthermore, the four sets of wall-mounted burners are supported and fixed by water-cooled walls and rigid beams, and are flexibly connected to other pipelines while ensuring sufficient expansion capacity. Different vertical tilt angles of the burner nozzles can adjust the position of the furnace flame center, which can be adjusted according to boiler operating conditions (coking status, steam temperature, fly ash carbon content, and NO₂). x The emissions, etc., are comprehensively determined. Since the combustion device and its related equipment (nozzle actuators, damper actuators) undergo three-dimensional thermal expansion with the water-cooled wall, flexible connections should be used when connecting various pipes, cables, etc. to it, and sufficient displacement should be ensured.

Claims

1. A device for improving combustion efficiency by co-firing coal gas in a large coal-fired boiler, characterized in that: It includes 12 gas burners, arranged in three layers: upper, middle, and lower. The upper and middle layers are arranged with tangentially round gas burners at the corners, while the bottom layer consists of four sets of wall-mounted burners located in the middle of the four walls of the boiler's water-cooled wall. The four sets of wall-mounted burners are arranged on a horizontal plane, perpendicular to the water-cooled wall. They work in conjunction with the tangentially round burners in the upper and middle layers to handle different co-firing conditions.

2. The device for improving combustion efficiency by co-firing coal gas in a large coal-fired boiler according to claim 1, characterized in that: The wall-mounted burner is connected to a gas pipeline on its right side and a secondary air pipeline on its left side.

3. The device for improving combustion efficiency by co-firing coal gas in a large coal-fired boiler according to claim 1, characterized in that: The wall-mounted burner has a pre-embedded flame detection sleeve for arranging flame detection devices.

4. The device for improving combustion efficiency by co-firing coal gas in a large coal-fired boiler according to claim 1, characterized in that: The four wall-mounted burners are supported and fixed by water-cooled walls and rigid beams, and are flexibly connected to other pipelines to ensure sufficient expansion capacity.

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