Optimum distribution control method for coal supply of coal-fired power units in sub-bin distribution

Abstract

The invention provides a separated bunker coal feeding thermal power generating unit coal feeding amount optimized distribution control method. According to the method, a proportional follow control system is used to control the coal feeding amount of each coal mill and add a speed limit module at the coal feeding amount instruction of each coal mill, the control end of each speed limit module is provided with a speed limit bias value setting module, and through setting the output value of each speed limit bias value setting module, the change rate of a poor quality coal feeding amount instruction is lower than the change rate of a good quality coal feeding amount instruction in a total coal feeding amount change. The speed limit module is added in a traditional coal feeding amount control logic, the change rate of each coal mill coal feeding amount and the single control of a change amplitude are realized, the problems of coal mill blockage, coal mill vibration and instable burner burning caused by the large coal feeding amount fluctuation of the coal mill and burner corresponding to poor quality coals in a unit load change process are solved completely, and thus the normal operation of a separated bunker coal feeding thermal power generating unit is ensured.

Description

technical field [0001] The invention relates to a method for optimizing the distribution of coal supply for a coal-fired power unit in separate bins and belongs to the technical field of power generation. Background technique [0002] In the coal market, the price of coal with high calorific value is obviously higher. The price of high-quality coal with a calorific value of 22MJ / kg is 2-3 times higher than that of low-quality coal with a calorific value of 15MJ / kg. The cost of coal combustion accounts for more than 70% of the overall operating cost of thermal power units. Under the basic conditions for the safe and stable operation of thermal power unit boilers, blending low-calorie low-quality coal can effectively reduce the fuel cost of thermal power companies and improve their profitability. In addition, due to the single use of low-quality coal and the pollution of the environment when stored and used, it is also in line with national economic and environmental protectio...

AI Technical Summary

Problems solved by technology

The resulting problems are as follows: the coal mill will lose its ability to adjust after manual switching, and the part of the change in the coal supply command is completely borne by other coal mills, resulting in poor operating conditions of other coal mills and burners; When the coal supply of the unit increases, the negative bias coal mill will not be blocked due to excessive coal supply, but when the coal supply decreases, it is prone to vibration due to too low coal supply

[0011] To sum up, the existing coal supply control method cannot ensure the stable operation of the coal mill and the burner when the coal is divided into bins, and there is an urgent need for a method that can set different coal supply according to the coal quality of each coal mill. Control method of increase and decrease rate and range

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