脱硫废水蒸发处理自动控制与保护逻辑

Automatic control and protection logic for evaporation treatment of desulfurization wastewater in thermal power plants

为实现电厂脱硫废水零排放智能控制,本文提出一种采用自动控制与保护逻辑的脱硫废水蒸发处理方法,利用抽取空气预热器前、后烟气管道中烟气的热能对脱硫废水进行蒸发处理。该控制系统为一个带有前馈控制的串级控制系统,前馈控制通过对空气预热器前、后烟气抽出管道上阀门初始开度的确定,控制除尘器入口烟气温度在合理范围内,串级控制保证整个系统稳定运行,同时设计了相应的保护逻辑。该控制系统能大幅降低运行操作的复杂程度,减少人为误操作的风险,有利于脱硫废水蒸发系统的稳定经济运行。

To realize intelligent control for zero discharge of flue gas desulfurization（FGD）wastewater in thermal power plants,this paper proposed a FGD waste water evaporation treatment method using automatic control and protection logic.This method takes use of the thermal energy of the flue gas in front of and behind the air pre-heater（AHP）to carry out evaporation treatment of the desulfurization waste water.This control system is a cascade control system with a feedforward control.The feedforward control keeps the flue gas temperature of at the electrostatic precipitator（ESP）inlet in a suitable range by controlling the initial opening degree of the valves on the pipes in front of and behind the AHP.The cascade control system ensures a long-term stable operation of the whole system.Moreover,the corresponding protection logic is designed.This control system can significantly reduce the complexity of the operation and reduce the risk of human mistakes,which is conducive to the stable and economical operation of the FGD wastewater evaporation system.