| The high coal consumption and high coal power generation in China determines the important role of coal for energy structure transformation and power grid peak regulation in the short term.The next stage of pollution prevention and control of coal-fired power generation will focus on the fine particle and desulfurization wastewater with high salinity and high chlorine.Considering the fugacity of fine particles and corrosivity of desulfurization wastewater,the paper proposed a new-type technology for the integrated and collaborative treatment of fine particulate and desulfurization wastewater.The technology uses enhanced chemical aggregation agents to make fine particles coagulate and grow up,and at the same time desulfurization wastewater is treated at different levels in different sections by the means of evaporation.Firstly,in order to choose the effective passivated agglomerants to inhibit the activity of chloride-ions in the wastewater,the experiment of corrosion behavior of low carbon steel in desulfurization wastewater after adding different passivated agglomerants were carried out.The results found that the XTG can effectively reduce the corrosion,and the combination of XTG and PAM or CTAC can further enhance the corrosion inhibition effect.The combination of 1.5g/L XTG and 1.5g/L CTAC had the most stable effect with the best corrosion inhibition efficiency of 75.53%.And,the corrosion rate was reduced by 71.82%,the actual corrosion rate was reduced by more than 70%,which had a certain guiding significance for alleviating the high chlorine corrosion and low temperature corrosion of desulfurization wastewater in the process of engineering application.Then,to research the evaporation process of desulfurization wastewater,the evaporation model of desulfurization wastewater was established.And the influence of chemical agglomerate solution on the flue gas flow field before and after the air preheater and the low temperature economizer was studied by CFD simulation.The results showed that the flue gas velocity field and pressure field were not affected by flow rate of desulfurization wastewater with 1.00 m3/h～2.50 m3/h,which only made the the flue gas temperature decrease by 1℃～6℃.In addition,the heat transfer process of desulfurization wastewater concentration was calculated and the characteristics of evaporation products were analyzed by XRD and XRF.Finally,the experiment of enhanced chemical aggregation agents to coordinate the control over the discharge of fine particles and desulfurized wastewater for 300MW coal-fired power was carried out.The results showed that the system had good load adaptability and working stability after sparying into enhanced chemical aggregation agents.The dust concentration decreased by 13.31%～32.19%after ESP.The temperature at the inlet of ESP decreased by about 6.5℃.And the sulfur trioxide removal rate reached 54.4%.In order to further investigate the effect of coupling dust removal with chemical agglomeration system and low temperature economizer,a 168h continuous operation test was carried out.This results showed that the system was not affected by the evaporation treatment of desulfurization wastewater in front of the air preheater,which reached the ultra-low emission standard.Meantime,the operating parameters of the system were optimized.The chemical agglomeration technology can co-control fine particles,desulfurization wastewater,SO3 and other pollutants,and solve the problems of dust accumulation in flue,high chlorine and low temperature corrosion,air preheater and other equipment blockage,etc. |
