基于趋势预判和强度自调节的脱硝控制策略研究

Research on Denitrification Control StrategyBased on Trend Prediction and Intensity Self-Regulation

构建新型电力系统对燃煤电站灵活性提出更高要求。机组频繁、快速变负荷给脱硝控制带来挑战。为解决传统控制存在的大迟延、强振荡等问题,提出兼顾响应速度和控制精度的脱硝控制策略。首先,基于运行参数对机组工况进行辨识和分类。然后,通过NO_x测量值变化趋势设计模糊规则修正表,对被调量进行趋势值预测修正以提高系统响应速率。最后,根据运行工况不同,从四个方面调节控制系统作用强度,以提升控制精度。工程现场的应用结果表明,该策略适用于机组全负荷运行工况。数据显示:NO_x排放均值提升6.2%;喷氨量减小14.06%;环保超标频次降低87.9%。NO_x控制水平及运行经济性由此得以提升。该研究打破传统控制中固定模型参数的局限性,可根据机组实际运行工况灵活调节模型强度,为实现火电热工精细化控制提供借鉴。

Building a new type of power system puts higher requirements on the flexibility of coal-fired power plants.Frequent and rapid load change of the unit brings challenges to denitrification control.To solve the problems of large delay and strong oscillation in traditional control,a denitrification control strategy is proposed to consider the response speed and control accuracy.Firstly,the working conditions of the unit are recognized and classified based on the operating parameters.Then,a fuzzy rule correction table is designed through the change trend of NO x measurement value,and the trend value prediction is corrected for the regulated quantity to improve the response rate of the system.Finally,according to the different operating conditions,the control system strength of action is adjusted in four aspects to improve the control accuracy.The application results in the project site show that the strategy is suitable for the full-load operating conditions of the unit.The data show that the average NO x emission is improved by 6.2%,the ammonia injection is reduced by 14.06%,and the frequency of exceeding the environmental protection standard is reduced by 87.9%. It improves the NO x control level and the operation economy.This research breaks the limitation of fixed model parameters in traditional control and can flexibly adjust the model strength according to the actual operating conditions of the unit,which provides a reference for realizing the fine control of thermal engineering in thermal power.