Combustion optimizing control system of circulating fluidized bed boiler in wide-range change of load

Abstract

The invention relates to a combustion optimizing control system of a circulating fluidized bed boiler in wide-range change of load. An optimizing controller comprises a boiler load adjusting loop and an in-boiler material distribution estimator, wherein the boiler load adjusting loop outputs a primary air quantity calculated value, a secondary air quantity calculated value and a fuel quantity calculated value to the in-boiler material distribution estimator; the in-boiler material distribution estimator outputs a material layer thickness judging result to an expert logic judging circuit; and the expert logic judging circuit outputs a final controlled quantity to a distributed control system (DCS) according to the input material layer thickness judging result and the measuring signal of process data, and inputs a temporary bed temperature modified value and a temporary secondary air modified value to the boiler load adjusting loop. In the invention, according to the characteristics of multiple variables, close coupling, large pure delay, time varying and the like of the combustion system of the circulating fluidized bed boiler, an in-boiler kinetic model is arranged in the in-boiler material distribution estimator, and the in-boiler kinetic model and the expert logic judging circuit are combined to estimate the quantity of material and carbon concentration of all parts so as to correct the air-coal ratio dynamically.

Description

technical field [0001] The invention relates to an optimization control system, in particular to a combustion optimization control system of a circulating fluidized bed boiler under a large range of load fluctuations. Background technique [0002] Circulating fluidized bed combustion boilers have developed rapidly in the past ten years because of their high efficiency, low pollution, and wide fuel adaptability. The combustion system of the circulating fluidized bed boiler reflects the structural characteristics of the circulating fluidized bed more concentratedly, and its combustion chamber is quite different from the furnace of the conventional pulverized coal boiler. A typical circulating fluidized bed boiler is divided into upper and lower parts. The upper part of the combustion chamber is the oxidation combustion zone, and the lower part is mainly the reduction combustion and sulfur fixation zone. It is composed of separation device, feeder and other parts. The combust...

AI Technical Summary

Problems solved by technology

The existing technology cannot solve the problems of ensuring the safety and economy of the circulating fluidized bed combustion and maintaining the stability of the steam pressure at the boiler outlet under the large-scale fluctuation of the steam load.

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