A method for automatic control of boiler steam temperature

Abstract

The embodiment of the invention discloses an automatic control method for boiler steam temperature, and relates to the technical field of boilers. The boiler steam temperature is controlled by four attemperation water control loops including a first first-stage control loop, a first second-stage control loop, a second first-stage control loop and a second second-stage control loop, according to animprovement method, a traditional PID control method is invariably adopted in the first second-stage control loop and the second second-stage control loop, the first first-stage control loop and thesecond first-stage control loop are subject to an improvement of artificial experience operation imitation, and automatic control over the boiler temperature is achieved. According to the automatic control method for boiler steam temperature in the embodiment, the automatic control method is adopted, the steam temperature is stabilized to be within the + / -3 DEG C scope, when the steam temperaturedeparture exceeds + / -5 DEG C, the temperature can be quickly and better controlled within the set value, namely the + / -3 DEG C scope, and the maximum temperature departure does not exceed + / -10 DEG C

Description

technical field [0001] The invention relates to the technical field of boilers, in particular to an automatic control method for boiler steam temperature. Background technique [0002] Boiler main steam temperature is one of the main parameters of boiler control, and its control effect is directly related to the quality of steam and affects the economical operation of the unit. Boiler main steam temperature is a complex controlled object, and all of them have relatively large hysteresis. Combustion changes, flue gas changes, changes in desuperheating water volume for manual intervention, changes in external main steam load, and changes in primary / secondary air Will affect the main steam temperature. [0003] In view of the above factors, the control of the main steam temperature not only requires a faster response speed and stabilization rate to external disturbances, but also requires a strong suppression of pressure changes in the desuperheating water, so that the system ...

AI Technical Summary

Problems solved by technology

According to the current traditional PID control plus manual adjustment method, the operation effect of the system is not ideal, the steam temperature fluctuates greatly (±10 degrees Celsius, and the short-term fluctuation exceeds ±15 degrees Celsius), and the operator manually intervenes and adjusts frequently, and the work intensity is high, which seriously affects the performance of the unit. safety and economy

For intelligent control methods such as fuzzy control and neural network control, although good results have been achieved in the study of main steam temperature control, they cannot be implemented in DCS due to the complexity of their calculations and the constraints of the DCS platform.

[0004] Chinese patent application number 200710028794.2 discloses an automatic control method of steam temperature, which aims to provide a boiler control method with stable operation and accurate air temperature control. Heat, according to the heat that needs to be desuperheated, adjust the desuperheating water flow after PID calculation, and calculate the actual desuperheating heat together with the measured water temperature before and after the desuperheater, and know the balance position between the actual desuperheating heat and the heat that needs to be desuperheated , this method still relies on the PID algorithm, and the response speed is still slow when the steam temperature fluctuates greatly

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