湿法脱硫的传质与化学平衡模型研究

Study of a Model Featuring Mass Transfer and Chemical Equilibrium for Wet Method-based Desulfuration

采用喷淋式吸收塔的石灰石-石膏湿法脱硫技术是目前燃煤电站使用最广的脱硫工艺。在吸收塔内,喷淋的液滴在上升的烟气中逆向下落,吸收烟气中的SO2。基于稳态假设,分析了液滴内的化学反应过程和液相成份的平衡关系,以及固体CaCO3的溶解速率模型。采用总的传质系数,建立了液滴吸收气相成份的传质速率模型。通过气液两相之间各个成份的物量平衡分析,建立了吸收区的控制容积平衡方程。该模型对工程应用具有指导意义,也可以进一步应用于吸收塔的仿真计算和流场数值模拟计算。

The technology of limestone-gypsum wet-method desulfuration by using a spray absorption tower is nowadays most widely used in coal-fired power plants.Inside the tower,the sprinkling liquid droplets will fall in an inverse direction against the rising flue gas flow to absorb SO2 in the flue gas.Based on a steady-state assumption,the authors analyzed the equilibrium relationship between the chemical reaction process in the droplets and liquid-phase constituents,and also presented a model featuring the dissolution velocity of solid CaCO3.By employing a total mass transfer coefficient,set up was a mass transfer rate model for droplet absorption-phase constituents.Through an analysis of the material quantity equilibrium of various components between the gas and liquid phases,established was an equilibrium equation for the controlled volume in the absorption zone.The model in question can provide guidance for relevant engineering applications,and can also be used for the emulation calculation of absorption towers and flow-field numerical simulation calculations.