Method of adjusting boiler load of circulating fluidized bed

Abstract

The invention relates to a method of adjusting boiler load of a circulating fluidized bed. The method includes the steps of 1, conveying raw coal and coal slime according to a set mixed burning ratio, allowing a boiler to function according to a preset load percentage a, detecting changes in the boiler load percentage a, and converting the load percentage a into a load variation b; 2, when the load percentage a meets 1-r / X< / =a< / =100%, executing a step 3, and when the load percentage a meets 1-r*(Y+1) / X< / =a< / =1-r*Y / X, and executing a step 4; 3, continuing to keep a coal slime conveying amount, and adjusting a raw coal conveying amount according to set correction factors so as to obtain the set load percentage a; and 4, decreasing the coal slime conveying amount to Y / X, and adjusting the raw coal conveying amount according to the set correction factors to obtain the set load percentage a. stepwise adjustment of the coal slime is used in the method, mixed burning ratio of the coal slime is increased, and quick response to load adjusting commands is provided.

Description

technical field [0001] The invention relates to the technical field of coal slime mixed combustion, in particular to a method for adjusting the load of a circulating fluidized bed boiler. Background technique [0002] The traditional circulating fluidized bed boiler can be mixed with a part of coal slime. One of the ways of co-firing with conventional coal fuel is to send raw coal and coal slime into the boiler separately. transported into the furnace. In order to control the steam temperature, the boiler generally adopts the control strategy of "fuel / feed water ratio" (commonly known as the coal-water ratio), that is, the fuel and the feed water input to the boiler are maintained at a set ratio, and according to the principle of energy balance, it is ensured that under different loads When the evaporation rate changes, the steam outlet temperature remains constant. [0003] Coal slime transportation generally adopts volumetric pumps, that is, the total volume to be transp...

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Problems solved by technology

However, when the calorific value of raw coal and slime changes, the heat input into the furnace will deviate from the original set value, and it is difficult to measure the deviation; in addition, the slime pipeline is long, and when the speed of the slime pump has been signaled, it will be delayed by 3 It takes ~5 seconds for the flow signal of coal slime to enter the furnace. This delay effect will lead to poor adjustment quality; at the same time, because coal slime is inconvenient to measure, the calorific value cannot be directly measured, and the composition and moisture content of different coal slimes are different. It also has a great impact on the calorific value of coal slime, so it is difficult for coal slime to directly participate in boiler load regulation, which is not conducive to increasing the proportion of coal slime blended combustion, and it is difficult to improve boiler combustion efficiency

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