Supercritical boiler fire coal heat value self-balance control loop distributed control system implementation method

Abstract

The invention discloses a supercritical boiler fire coal heat value self-balance control loop distributed control system implementation method. The method comprises the steps of outputting a final coal feeder rotation speed command after PID adjustment is carried out on a received coal feed quantity command and a total coal quantity command with a heat value corrected, wherein the total coal quantity command with the heat value corrected is a total coal quantity command output by multiplying a dynamically-measured total coal feed quantity by a heat value balance correction coefficient, and the heat value balance correction coefficient is a delayed heat value balance correction coefficient. According to the method, soft measurement of a fire coal heat value can be achieved based on a unit DCS platform, additional investment is not needed, and a soft measurement signal of the fire coal heat value makes it convenient for operating personnel to monitor the quality of fired coal in real time and guides boiler combustion adjustment. A fire coal heat value self-balance control loop is designed, and therefore a unit coordinated control system has the ability to adapt to various types of coal, and the operation stability and the economy of a unit are improved.

Description

technical field [0001] The invention belongs to the thermal engineering measurement field of a thermal power plant, and in particular relates to a method for realizing a decentralized control system (DCS) of a self-balancing control loop of a supercritical boiler coal-fired calorific value. Background technique [0002] At present, power plant boilers have various coal sources and seriously deviate from the designed coal types. In order to reduce fuel costs, power generation companies continue to increase coal blending efforts. Affected by factors such as blending sites and blending plans, coal blending and blending The uniformity is difficult to be effectively controlled, and the calorific value of the furnace coal changes frequently, which affects the coordinated control performance of the unit, and even brings hidden dangers to the safe operation of the boiler. [0003] In the direct energy balance coordinated control scheme of the drum boiler, the heat signal represents ...

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Problems solved by technology

However, supercritical once-through boilers have small energy storage and cannot construct heat signals similar to drum boilers. In its indirect energy balance coordinated control scheme, fuel calorific value disturbances are usually corrected by closed-loop main steam pressure. This passive correction method eliminates deviations Weak, especially in the condition of AGC with continuous and large load changes, the accumulated deviation will lead to long system stabilization time and large fluctuations in unit operating parameters

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