Pressure difference control method and control device for air pre-heaters of coal-fired power plant

Abstract

The invention provides a pressure difference control method and control device for air pre-heaters of a coal-fired power plant. The method comprises the steps that for each of the two air pre-heaters, the pressure difference value between the cold end and the hot end of the air pre-heater, the exhaust gas temperature of the air pre-heater and the boiler load of a coal-fired power plant are obtained in real time; if the pressure difference value is larger than a preset pressure difference value and the boiler load is smaller than a preset load value, a first pipeline is closed, and a second pipeline of the air pre-heater is connected to increase the smoke exhaust temperature of the air pre-heater till the smoke exhaust temperature is increased to a preset temperature; and a soot blower corresponding to the air pre-heater is controlled to conduct soot blowing on the cold end of the air pre-heater according to preset soot blowing pressure till the pressure difference value between the cold end and the hot end of the air pre-heater is smaller than the preset pressure difference value. The pressure difference control method and control device have the advantages that the soot blowing effect is remarkable, the soot blowing time can be effectively shortened, the pressure differences of the air pre-heaters can be reduced in time, the operation current of a draught fan can be reduced, and energy consumption is reduced.

Description

technical field [0001] The invention relates to the technical field of differential pressure control of an air preheater in a coal-fired power plant, in particular to a method for controlling the differential pressure of an air preheater in a coal-fired power plant and a device for controlling the differential pressure of an air pre-heater in a coal-fired power plant. Background technique [0002] For coal-fired power plants, nitrogen oxides, SO 2 , SO 3 and dust, and the vanadium pentoxide in the denitrification catalyst (SCR) can easily convert the SO in the flue gas 2 Oxidation to SO 3 , increasing the SO in the flue gas 3 concentration. SO in flue gas 3 After combining with water vapor, it condenses at the cold end of the air preheater to form H 2 SO 4 . On the one hand, H 2 SO 4 Reacting with metal elements (Ca, Mg, Cu, Fe, etc.) 2 SO 4 It will also absorb dust in the flue gas and cause dust accumulation at the cold end of the air preheater, which is also an...

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Problems solved by technology

[0005] The purpose of the embodiment of the present invention is to provide a method and control device for controlling the pressure difference of the air preheater in a coal-fired power plant, so as to at least solve the above-mentioned high pressure difference of the air preheater, so that the outlet pressure of the blower is high, so that the blower enters the stall zone and limits the unit. The operating load of the fan will cause a large increase in the operating current of the fan, seriously affecting the economical operation of the problem

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