Thermoelectricity boiler drum liquid level control method

Abstract

The invention relates to a thermoelectricity boiler drum liquid level control method, three variables of a drum liquid level, feed water flow and steam flow are taken as processing objects, a feedforward and cascade stage structure is wholly adopted for a control system, a conventional PID adjuster with the drum liquid level as a detecting and controlling variable is adopted for a main adjustor, and the deviation between the set value SP of the drum liquid level and the actual measured value LT is calculated through the PID adjuster and output as the set value of the feed water flow; the measured value of the drum externally supplied steam flow is taken as a feedforward control variable; a single-neuron self-adaptive PSD adjuster with the feed water flow as a detecting and controlling variable is adopted for an auxiliary adjustor. Through the technical scheme, aiming at complex conditions of boiler drum operation, advanced, reliable and practical calculation is adopted to achieve self-adaptive optimum control over the boiler drum liquid level and ensure efficient and stable production of a boiler.

Description

technical field [0001] The invention relates to a boiler liquid level control method, in particular to a thermoelectric boiler steam drum liquid level control method. Background technique [0002] The boiler drum liquid level control system is an important key process in the boiler production process. The stability of the boiler drum liquid level is crucial to maintaining boiler safety, improving boiler efficiency, and reducing production costs. During boiler operation, the steam drum liquid level There are many factors affecting the stability, the main ones are the feed water flow and steam flow. When the feed water flow increases, because the temperature of the feed water is relatively low, it absorbs heat from the original saturated water and reduces the drum water volume. Therefore, The water level of the steam drum does not rise immediately at the beginning, but shows an initial inertia stage; when the steam load increases, from the perspective of material balance, the ...

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Problems solved by technology

[0002] The boiler drum liquid level control system is an important key process in the boiler production process. The stability of the boiler drum liquid level is crucial to maintaining boiler safety, improving boiler efficiency, and reducing production costs. During boiler operation, the steam drum liquid level There are many factors affecting the stability, the main ones are the feed water flow and steam flow. When the feed water flow increases, because the temperature of the feed water is relatively low, it absorbs heat from the original saturated water and reduces the drum water volume. Therefore, The water level of the steam drum does not rise immediately at the beginning, but shows an initial inertia stage; when the steam load increases, from the perspective of material balance, the steam volume is greater than the feed water volume, and the water level should drop, but in practice, a sudden increase in the steam load will cause As a result, the pressure of the steam drum decreases, the volume of steam in the steam-water mixture increases rapidly, and the water level rises rapidly, that is, the "false water level" phenomenon; The physical characteristics will change accordingly, which will cause the problem of model mismatch; in short, the boiler drum liquid level system is a system with large inertia, long lag time, and nonlinear time-varying

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