Combustion system and method of inverted-alpha shaped flame air distribution type layered boiler

Abstract

The invention discloses a combustion system and method of an inverted-alpha shaped flame air distribution type layered boiler, and belongs to the technical field of boilers. The combustion system comprises a front arch, a rear arch, a fire grate and an air distribution system, wherein the front arch and the rear arch are separately arranged aslant; the top height of the front arch is less than that of the rear arch; the rear arch is shorter than the front arch; an included angle of the front arch and the rear arch is an obtuse angle; the front arch, the rear arch and a partitioning plate are divided into a front zone and a rear zone, the front zone is a combustion zone and the rear zone is a cooling area; the air distribution system comprises a main pipe, air blowers, a fume exhaust pipe and a plurality of air distribution pipes; the fume exhaust pipe and one end of each of the plurality of air distribution pipes are connected with the main pipe; the other end of each of the pluralityof air distribution pipes extends into a combustion chamber from the front arch or the rear arch; an adjusting valve is arranged on the each air distribution pipe; the other end of the fume exhaust pipe extends into a cooling fume exhaust zone, the main pipe communicates with an air pre-heater of an existing boiler; and the air blowers are separately arranged on the main pipe and the fume exhaustpipe. According to the system and the method disclosed by the invention, generation of nitrogen oxide can be reduced, and fume exhaustion loss is reduced.

Description

technical field [0001] The invention relates to a boiler and a combustion method for the boiler, in particular to a combustion system and method for a reverse α-shaped flame-distributing air-distributing layer-burning furnace, belonging to the technical field of boilers. Background technique [0002] Layer-fired furnaces are widely used because of their simple structure, convenient operation, and low requirements for the quality of firemen. According to statistics, they account for as much as 90% of industrial boilers, and are widely used in many industries such as building materials, chemicals, printing and dyeing, heat treatment, and pharmaceuticals. , is an important combustion method for boilers in our country. The heat loss of a layer combustion furnace is a factor that affects its combustion efficiency. The existing layer combustion rate has the following problems: [0003] 1. The combustion control of the existing layer-burning furnace is not good, and it is difficul...

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Problems solved by technology

[0003] 1. The combustion control of the existing layer combustion furnace is not good, and it is difficult to burn out the coal seam. The data shows that in many cases, the carbon content of the grate ash can reach 30%-40%

For example, the invention patent application "A Reciprocating Grate Layer Combustion Furnace" (application number: 201310365289.2, application date: 2013.08.19) uses the rear arch to re-radiate the coal to ignite and lengthen the grate to burn the coal, which has not completely solved the problem of coal burning. Difficult burnout problem and increased furnace size

[0004] 2. The α flame formed by the front and rear arches is used. Because the high-volatile air flow in the front and the high-temperature oxygen-enriched air flow in the rear are difficult to achieve good mixing, in order to burn out the combustible gas, there are more unburned gases in the flue gas, and there is smoke. The problem of excessive air coefficient in the gas is large, resulting in a large heat loss in the exhaust smoke; at the same time, under low load conditions, the α flame is difficult to form, and there are more unburned gases in the flue gas

The flue gas recirculation technology has the problems of increasing the carbon content of the ash and further reducing the furnace temperature, which leads to a decrease in the thermal efficiency of the bed combustion furnace.

Due to the limited furnace space and low furnace temperature of the layer-burning furnace, the SNCR technology often uses ammonia water with a low reaction temperature as the reducing agent, which often encounters problems such as difficulty in finding effective ammonia injection points, insufficient reduction reaction time, and increased ammonia escape rate. escape will also cause serious air pollution problems

For example, the invention patent application "A denitrification system coupled with flue gas recirculation for chain furnace" (application number: 201610817509.4, application date: 2016.09.12) adopts coupling technology, which may cause uneven temperature distribution in the furnace, Problems of limited space and low temperature

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