Simulation And Experimental Research On Removal Of Arsenic,selenium And Lead From Coal Burning By Heterogeneous Condensation Technology

Coal is the main component of our country’s energy,accounting for more than 50%of our country’s primary energy consumption throughout the year.Coal-fired power plants are one of the main ways to use coal.The harmful trace elements such as arsenic（As）,selenium（Se）and lead（Pb）released during coal combustion have caused serious harm to human health and the environment.Through the heterogeneous agglomeration device,agglomeration adsorbent is sprayed into the flue gas which can effectively agglomerate the fine particles and gaseous trace elements in the flue gas to large particles,thereby improving the dust collector’s capture efficiency of such elements.This paper mainly studies the effect of heterogeneous agglomeration on the enhanced removal of harmful trace elements in coal-fired power plants,which is mainly divided into three parts:First,the Monte Carlo method is used to solve the model of heterogeneous agglomeration and adsorption of fine particles of harmful trace elements.The results show that heterogeneous agglomeration can promote the growth of fine particles into larger particles,and at the same time,and the harmful trace elements on the particles is also similar.Through coagulation,the harmful trace elements originally enriched in fine particles are transferred to the large particle area as the particles grow,and the increase in the flow rate of the sorbent can improve the coagulation efficiency.Design,simulate and test the heterogeneous agglomeration and device for a small test platform with a combustion flue gas volume of 100m³.The results show that the heterogeneous agglomeration and the adsorbent sprayed into the flue will cause the outlet temperature of the agglomeration chamber to decrease slightly,At the same time,in the atomization area,the flue gas flow rate increased slightly,the concentration of particulate matter after the precipitator was reduced from 40mg/m³to 20mg/m³,the efficiency of the precipitator was increased from80.3%to 90.15%,and the gaseous arsenic and selenium were greatly reduced.After phase agglomeration,the gaseous arsenic concentration decreased from 0.358μg/m³ to 0.118μg/m³,a decrease of 67.0%,and the gaseous selenium concentration decreased from 0.871μg/m³ to0.161μg/m³,a decrease of 81.5%.For a 330MW coal-fired unit in Hubei,an industrial demonstration application experiment of heterogeneous agglomeration technology was carried out.The results showed that the content of harmful trace elements on the ESP inlet particles increased after the sorbent was injected into the flue gas.Among them,the increase of Se element is particularly obvious in PM_2.5 and PM₁₀.After agglomeration,the proportion of 2.5-10μm particles increased from1.89%to 11.46%,the proportion of 1-2.5μm particles rose from 0.56%to 48.77%,and the proportion of PM₁ decreased from 97.55%to 39.77%;After agglomeration,the content of arsenic,selenium,and lead in gypsum was reduced by 32.5%,67.6%,and 30.0%,respectively,and ESP’s effect on the removal of harmful trace elements was significantly improved.Compared with uncondensed conditions,70.6%,19.9%,70.9%of arsenic,selenium,and lead will be transferred from gaseous or PM₁₀ to particles above 10μm and emitted to the atmosphere before ESP.the concentration of arsenic,selenium,and lead finally discharged into the atmosphere is reduced by 69.3%,77.8%,and 46.5%,respectively,which shows heterogeneous agglomeration and plays a key role in the control of harmful trace elements.