Coal breakage control method of coal mills under low load operation mode of three coal mills

Abstract

The invention relates to a coal mill coal interrupting control method under a low-load three-coal mill running mode. The method comprises the steps that whether coal mill coal interrupting happens ornot is determined under the low-load three-coal mill running mode; if coal mill coal interrupting happens, judgment is made according to the actual output of a unit and the maximum output of remainingtwo coal mills, and different control strategies are taken for unit fuel control, water supply control and steam turbine control; and safe and stable operation of the unit is maintained. Compared with the prior art, the coal mill coal interrupting control method solves the problem about control over coal mill coal interrupting under the low-load three-coal mill running mode, and the technical blank in the aspect is offset.

Description

technical field [0001] The invention relates to the technical field of thermal automatic control and protection, in particular to a method for controlling coal breakage of coal pulverizers under the operation mode of three coal pulverizers under low load of a thermal power unit (hereinafter referred to as: three pulverizers under low load mode). Background technique [0002] Due to the increasing installed capacity of new energy units, the low-load operation of thermal power generating units has become the norm. As an important auxiliary equipment of the boiler system, the coal mill's operation mode directly affects the safety, stability and economy of the unit. At present, considering the safe and stable operation of the unit during the low-load period, four coal mills are still running under low-load conditions. One of the coal mills trips or breaks coal, and the other three coal mills can quickly increase output to maintain the boiler. Reduce the heat load and reduce the...

AI Technical Summary

Problems solved by technology

Under the low-load three-mill operation mode, if any coal mill cuts off coal, since the output of the remaining two coal mills is limited by the maximum coal output of a single unit, it may not be possible to maintain the normal output of the unit, and the thermal load of the boiler will drop suddenly, seriously affecting the stability of the boiler. Combustion; due to the low feedwater flow rate of the low-load unit, the speed of the small machine is close to the lower limit, it is difficult to control the feedwater flow rate when the coal mill is cut off, the boiler steam temperature fluctuates greatly, and it is easy to enter wet operation, which affects the safe and stable operation of the unit

At the same time, the repeated coal cutting and incoming coal of the coal mill also greatly disturb the normal operation of the unit, which is not conducive to the safe and stable operation of the unit under low-load conditions

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