Theoretical Modeling Of Wet Flue Gas Desulfurization Absorption Tower

In recent years,the state has made great efforts to promote the construction of flue gas desulfurization in thermal power plants,and the domestic desulfurization market has developed rapidly.At present,the limestone-gypsum method is the most widely used and most mature technology for the desulfurization of coal-fired power plants in China.The most important equipment of limestone wet flue gas desulfurization is desulfurization absorber.In-depth study of its internal mechanism is of great significance for improving the operation stability and desulfurization performance of desulfurization system.The purpose of this paper is to establish a mechanism model by analyzing the complex mass transfer and chemical reaction process in absorption tower.The simulation analysis is carried out on the spray tower of limestone gypsum wet flue gas desulfurization system of a 350 MW unit.The main work and results of this paper are embodied in:(1)The absorption tower is divided into some regions,determine the modeling targets in different regions and establish the corresponding mechanism model.Using the method of piecewise processing.the sulfur dioxide absorption region is divided into different heights of the "cell" by the slurry droplet falling distance and exposure time,according to the motion characteristics and mass transfer chamber,desulfurization efficiency and pressure drop is calculated,and then get the absorption efficiency calculation method and the pressure drop across the region;the pH value of the slurry zone is described as a function of the concentration of the major components in the slurry;mist pressure drop according to velocity of flue gas is divided into low and high speed two stage calculation,and the overall defog efficiency is obtained according to the gas liquid separation efficiency of the droplets of different diameters.(2)Based on the STS simulation support platform,the real-time simulation algorithm of absorption tower is designed,and the main desulfurization system model is built.The simulation example of a domestic 350 MW generating unit WFGD system spray tower is carried out,and the simulation results are consistent with the actual operation data.Finally,the simulation experiments were carried out to analyze the effects of the inlet flue gas flow,the slurry circulation,the pH value of the slurry,the size of the slurry and the size of the slurry on the desulfurization efficiency.