A kind of prevention and control method of superheater tube wall overtemperature

Abstract

The invention discloses a method for preventing and controlling overtemperature of a superheater tube wall, which relates to the technical field of superheaters, and specifically includes S1, desuperheating water control logic and S2, desuperheating water control component input / reset logic. The method for preventing and controlling the overtemperature of the superheater tube wall is to introduce the wall temperature of the screen superheater as the feedforward signal of the primary desuperheating water, and the wall temperature of the high temperature superheater as the feedforward signal of the secondary desuperheating water. When the temperature is too high and the heating rate is changed too fast, the control component of the desuperheating water can be input and maintained in time, which is conducive to timely response to the rapid temperature rise when the load changes rapidly, and when the steam temperature begins to drop or the heating rate is lower than the threshold value, The control component of the desuperheating water will not exit immediately, and there is a switching difference area between the two, which can effectively reduce the number of actions of the desuperheating water valve and prolong the life of the equipment, and the withdrawal conditions of the desuperheating water are different from the input conditions, which can control the desuperheating water more effectively. flow.

Description

technical field [0001] The invention relates to the technical field of superheaters, in particular to a method for preventing and controlling overtemperature of a superheater tube wall. Background technique [0002] The superheater steam temperature control is an important part of the thermal power generation control system, which plays a vital role in the safe and economical operation of the thermal power control system. In order to improve the comprehensive frequency regulation performance of the unit, advanced control strategies are adopted through the external system. , The original AGC system, coordinated control system, fuel control system, primary superheated steam temperature control system, secondary superheated steam temperature control system, etc. of the unit were frequency-modulated. It often occurs in the process, and the over-temperature increases the thermal stress on the heating surface, and the frequent over-temperature increases the fatigue loss of the hea...

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Problems solved by technology

[0004] Aiming at the deficiencies of the prior art, the present invention provides a method for preventing and controlling overheating of the tube wall of the superheater, which solves the following problems in the closed-loop control system adopted by the existing steam temperature control system unit under normal working conditions in the above-mentioned background technology Defects: The response of the superheater tube wall overtemperature circuit is slow, the adjustment rate is low, and it cannot cope with the rapid temperature rise when the load changes rapidly; the control accuracy of the desuperheating water in the control circuit is low, and there is no precise input and withdrawal and maintenance logic, resulting in valves Frequent switching, reducing the life of the equipment

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