Pulverized coal co-combustion system of industrial boiler

Abstract

The invention discloses a pulverized coal co-combustion system of an industrial boiler. With the system, layer combustion and suspension combustion can form in a furnace. The system includes a boiler, a raw coal supply device and a co-combustion device. The boiler comprises a furnace, a coal inlet located at the lower part of a front end wall, and a chain grate disposed at the lower part of a furnace inner chamber. The raw coal supply device is connected to the coal inlet through a coal hopper. The co-combustion device is arranged at the boiler tail, and is composed of a boiler-front mill, a pulverized coal combustor and a pulverized coal conveying pipe. The boiler-front mill includes a rotation shaft running through a primary milling chamber, an intermediate milling chamber and a fine milling chamber connected in order, a primary hammer type impeller, an intermediate hammer type impeller and a final hammer type impeller. The front end wall upper part of the primary milling chamber is provided with a coal inlet, and the chamber wall upper part of the fine milling chamber is provided with a pulverized coal nozzle. The pulverized coal combustor includes a combustor body and a combustion nozzle. The combustor body is equipped with a secondary air inlet and a pulverized coal inlet. And the pulverized coal conveying pipe connects the pulverized coal inlet of the combustor body and the pulverized coal nozzle of the boiler-front mill.

Description

technical field [0001] The invention relates to a coal-fired industrial boiler, in particular to a pulverized coal mixed combustion system of the industrial boiler. Background technique [0002] Chain grate boiler is currently the main type of coal-fired industrial boiler in my country. Due to its advantages of simple structure, convenient operation and low price, the market share is very high, reaching more than 60% of the total. It is widely used in chemical industry, papermaking, Textile, heating and other industries. However, the operating thermal efficiency of the chain grate boiler in use is far lower than the design thermal efficiency. The reason for this is that in addition to the operation, the most fundamental reason lies in the layer combustion method adopted by the chain grate boiler and the use of coal in my country. Due to the poor adaptability of coal types of chain grate boilers, the requirements for coal particle size and coke slag characteristics are relati...

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Problems solved by technology

However, the operating thermal efficiency of the chain grate boiler in use is far lower than the design thermal efficiency. The reason for this is that in addition to the operation, the most fundamental reason lies in the layer combustion method adopted by the chain grate boiler and the use of coal in my country.

Due to the poor adaptability of coal types of chain grate boilers, the requirements for coal particle size and coke slag characteristics are relatively high. The optimal particle size range of coal is 6-25mm, and the coke slag characteristic is ≤5", but the proportion of pulverized coal with a particle size of less than 6mm and fine coal less than 13mm in the actual coal used by industrial boilers is as high as 30%, which is difficult to meet the requirements of chain grate boilers. Coal Conditions

The large difference between the type of coal burned in the design of the boiler and the type of coal actually used has greatly affected the economic operation of the boiler, making the operating efficiency of the chain grate boiler only about 70% for a long time

In recent years, with the continuous rise of coal prices and the improvement of energy conservation awareness, pure pulverized coal combustion technology has gradually been applied to the field of industrial boilers. However, the use of pulverized coal combustion technology in industrial boilers can only burn high-quality coal, poor combustion stability and easy coking And other issues

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