1000 MW超超临界机组SCR脱硝喷氨控制策略的优化与改进

Optimization and Improvement of Ammonia Spray Control Strategy for SCR Denitrification in 1000 MW Ultra-supercritical Unit

针对某发电厂1 000 MW超超临界机组SCR脱硝喷氨控制系统存在的问题,包括控制对象不准确、测量参数可靠性低、喷氨调节阀特性差、CEMS反吹和标定干扰自动调节等,对不同煤种与脱硝入口NOX浓度关系、磨煤机启停方式对脱硝入口NOX生成的影响进行了分析。采用基于前馈与变参数控制的脱硝控制优化策略,实现了喷氨调节自动控制全程投入,可将系统出口NOX浓度控制在50mg/m3以内且波动较小,SCR脱硝系统控制效果良好。

Aiming at the problems existing in ammonia spray control system for SCR denitrification in 1 000 MW ultra-supercritical unit in a power plant such as inaccurate control object,low reliability of measuring parameters,poor characteristic of ammonia spray control valve,CEMS blow back blow and automatic calibra-tion interference regulation.The relationship between different coal types and NOx concentration at inlet and the influence of coal pulverizer startup/shutdown mode on NOx generation are analyzed.The optimized control strategy of NOx control based on feedforward and variable parameter control is adopted,thus the whole pro-cess input of ammonia spray regulation is realized.NOx concentration can be controlled within 50 mg/m3 with smaller fluctuation.Control effect of SCR denitrification system is favorable.