Combustion control method of boiler

Abstract

Provided is a combustion control method of a boiler. The boiler comprises a coal mill used for producing coal dust, a coal pulverizing system connected with the coal mill and used for screening coal dust, a hearth connected with the coal pulverizing system and used for combusting coal dust and a primary air fan connected with the coal mill, the coal pulverizing system and the hearth by means of air channels. The control method is described in that an operation oil combustor performs ignition and combustion when an ignition condition in the hearth is satisfied such that temperature and pressure in the hearth are increased and boosted; temperature of secondary air and of smoke at the outlet of the hearth are obtained; when temperature of secondary air reaches the first pre-set value and temperature of smoke at the outlet of the hearth reaches the second pre-set value, an air channel between the primary air fan and the coal pulverizing system is opened and a pulverized coal exhauster of the coal pulverizing system is started; and the primary air fan and the coal mill are started by opening the air channel between the primary air fan and the coal mill. The combustion control method of the boiler ensures that exhaust gas can be fully combusted after entering the hearth in such a manner that the pre-set condition in the hearth is reached by means of the operation oil combustor.

Description

technical field [0001] The invention relates to power plant boiler technology, in particular to a boiler combustion control method using an intermediate storage type pulverizing system. Background technique [0002] At present, the boiler pulverization system of a large-scale power plant adopts an intermediate storage type pulverization system, which includes a coarse powder separator, a fine powder separator, a coal powder bin, and a powder discharge fan. The boiler also includes a coal mill for making pulverized coal and a furnace for burning pulverized coal gas. A plurality of burners are arranged on the furnace, and a primary fan and a blower are connected through an air duct. Wherein a plurality of burners are divided into a primary air spout, a secondary air spout and a tertiary air spout according to the combustion air. [0003] The working principle of the above boiler is roughly as follows: [0004] The pulverized coal is produced by the coal mill, and after pass...

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Problems solved by technology

[0006] The concentration of pulverized coal in exhaust gas (tertiary air) is low, and the distance from the nozzle of the tertiary air to the main combustion area is relatively high. At the initial stage of boiler startup, the combustion temperature in the furnace is low, and the exhaust gas is injected into the furnace through the nozzle of the tertiary air, which is easy to control. It leads to unstable combustion and fire extinguishing. Due to incomplete combustion, there is a greater possibility of secondary reburning in the flue at the tail of the boiler, which brings greater safety hazards to the safe operation of the boiler.

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