Load control method and system for CFB (Circulating Fluidized Bed) boiler for blending combustion of coal slime

Abstract

The invention discloses a load control method and system for a CFB boiler mixed with coal slime. The soft measurement model of the coal slime amount is constructed through the compression frequency of the coal slime pump and the pressure condition of the coal slime pump. Based on the coal slime soft measurement value, according to the energy balance principle, the total amount of the in-furnace fuel is converted, and in order to guarantee the stability of the in-furnace fuel, after the coal slime amount changes, the corresponding fire coal amount is increased or decreased, so that the balance of the in-furnace fuel amount and the boiler load is guaranteed. The air distribution system of the boiler is controlled according to the total fuel entering the boiler and the air-coal ratio of the boiler, and the purpose of rapid and reasonable distribution is achieved. On the premise that the total fuel quantity is not changed, the bed temperature of the corresponding bed area is controlled through the coal slime quantity, the oxygen content of the two corresponding sides is controlled through the fire coal quantity, the purpose of balancing the bed temperature and the oxygen content is achieved, and finally the purposes of safe operation, stable operation and economical operation of the boiler are achieved.

Description

technical field [0001] The invention relates to the field of CFB boiler load control, in particular to a CFB boiler load control method and system for burning coal slime. Background technique [0002] Coal slime is the main by-product produced in the process of raw coal washing and processing in large mining areas. Due to high water content, high viscosity, low calorific value and difficulty in transportation, it runs off in water and pollutes soil and groundwater; it is air-dried and flying, and dust pollution is difficult to cure. Utilizing the characteristics and advantages of the circulating fluidized bed unit, purchasing and blending a part of coal slime can not only reduce costs and create benefits, but also solve the pollution problem of coal slime. s Choice. [0003] Most of the sites do not have a metering device for the amount of slime, which brings a series of problems. For example, the difference in the amount of coal slurry fed into the furnace causes the imba...

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Problems solved by technology

[0005] Due to the difference in the amount of water mixed with the slime, the amount of slime actually included in the furnace varies greatly, and there is no actual measuring instrument for the change of the amount of slime, which makes the operator unable to detect it in time, resulting in load fluctuations and unbalanced air distribution. The frequent adjustment of the operator causes the labor intensity of the operator to be high, which not only affects the economy of the boiler, but also affects the safety of the boiler

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