A Control Method for Bed Material Balance of Underpants Leg Type Circulating Fluidized Bed Boiler

Abstract

The invention discloses a method for controlling the bed material balance of a breeches-leg shaped CFBC (circulating fluidized bed boiler). The method is implemented through calculating the pressure drop of an air-distribution plate according to the characteristic data fitting function and actual primary air volume of the air-distribution plate, and then further obtaining the pressure drops of corrected beds for balancing the bed material quantity more accurately; by taking the difference between the pressure drops of the corrected beds on both sides as feedback quantities, and through using an auto-disturbance rejection control algorithm, calculating the correction quantity of an active primary air set value; respectively adding and subtracting the correction quantity into and from 1 / 2 of a total primary air volume set value, taking the obtained values as set values of two controllers for regulating the air volumes of two sides, and controlling the openings of primary air adjusting doors on both sides through the two controllers; taking a value obtained by adding the total pressure drop of the inlet and outlet of a hearth into a positive offset as a set value of a controller for regulating the air pressure, comparing the set value with the pressure feedback of a primary air mother-tube, controlling the guide vane opening of a primary air fan through a regulator, providing a sufficient air pressure, and normally operating in cooperation with primary air volume control. A primary air control system designed in the invention can automatically adjust the bed material balance, and effectively shorten the duration time that bed material unbalance causes adverse impact on the system.

Description

Technical field [0001] The invention relates to the technical field of circulating fluidized bed boiler unit control, in particular to a method for controlling the bed material balance of a pant leg type circulating fluidized bed boiler. Background technique [0002] From the perspective of energy structure, my country is one of the few countries in the world that uses coal as the main energy source. During the combustion process of coal, especially when the combustion efficiency is not high enough, a large amount of ash, dust, and waste water will be produced. , SO 2 , NO x Such pollutants, if not properly treated, will seriously disturb the ecological environment and even cause permanent damage. In addition, although China's coal resources are abundant, the outstanding feature is the diversification of types and the scarcity of high-quality coking coal. Therefore, higher requirements are put forward for the fuel adaptability of coal-fired boilers. From a long-term perspective, h...

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Problems solved by technology

[0004] The existing design of the primary air control system of the underpants leg type CFB unit has not yet made corresponding improvements to the problem of "turning over the bed". It mainly relies on two independent controllers on the left and right sides to control the primary air volume. It is often impossible to make corrections in time; the design of another part of the control system has been partially improved for the balance of bed materials, such as adding corresponding compensation or correction for the opening of the primary air conditioning door on both sides, but most of them are based on field experience and rely on manual judgment and adjustment. The compensation of the air volume on both sides fails to take full advantage of the advantages of automatic control, the method is not applicable, and is highly dependent on the skills of the operator

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