燃煤电厂旁路烟气干燥塔控制技术开发

Development of Control Technology for Bypass Flue Gas Drying Tower of Coal-Fired Power Plant

以浙江两电厂为研究对象,分析了旁路烟气干燥脱硫废水零排放技术的控制难点,以不影响粉煤灰质量为目标,建立了多参数控制模型,在考虑烟气酸露点情况下确定最低烟气温度、最大脱硫废水处理量;同时基于能量平衡的精确控制技术和基于关键参数的软测量模型的互为备用,实现了脱硫废水的高效、低能耗干燥。台州第二发电厂脱硫水质控制限制的计算表明,粉煤灰可用作普通混凝土添加剂;长兴电厂脱硫废水干燥塔在旁路烟气挡板门全开的情况下,烟气入口温度357℃,脱硫废水质量流量达到4200 kg/h时,出口温度仍有117℃;而在深度调峰工况,烟气入口温度下降到280℃时,出口温度高于110℃的下线预警值时,系统出力为1750 kg/h,实验结果与基于能量平衡算法的理论预期基本一致。

Taking two Zhejiang power plants as the research objects,the difficulties of zero discharge control technology for desulphurization wastewater from bypass flue gas drying tower are analyzed.In order to keep the quality of fly ash unchanged,a multi-parameter control model is established to determine the minimum flue gas temperature and the maximum desulphurization wastewater treatment capacity under the consideration of flue gas acid dew point.At the same time,the accurate control technology based on energy balance and the soft sensing model based on key parameters are both implemented to backup each other,such that the goal of high efficiency and low energy consumption drying of desulphurization wastewater is achieved.The calculation of desulphurization water quality control limit of Taizhou Second Power Plant shows that fly ash can be recycled as ordinary concrete additive.As for the drying tower of Changxing Power Plant,with the flue gas baffle door fully open,when the inlet temperature is 35°C and the mass flow rate of desulphurization wastewater reaches 4200 kg/h,the outlet temperature still remains at 117°C,but once the inlet temperature of flue gas drops to 280°C and the outlet temperature climbs above 110°C,the output of the system then becomes 1750 kg/h,which is basically consistent with the theoretical expected value based on energy balance algorithm.