Emission Analysis And Control Technology Of Typical VOCs Sources In Coal Direct Liquefaction Project

In recent years,China's urban air pollution has exceeded the standard,regional and complex air pollution has become increasingly prominent,the overall form of the atmosphere is severe,the mutual pollution between cities is more significant,and atmospheric heavy pollution is frequent.The secondary pollution characterized by fine particles,ozone and acid rain is intensifying.Volatile organic compounds(VOCs)as a common precursor of ozone(O3)and fine particulate matter(PM2.5)are gradually gaining the attention of environmental protection authorities,experts and the public.VOCs have a wide variety of substances,which not only cause atmospheric pollution,but also have the effects of toxic and harmful,destroying the ozone layer and warming the world.At present,the atmospheric environmental problems mainly lie in the excessive emission of artificial VOCs,and the VOCs emissions of industrial enterprises are mainly based on unorganized emissions,with many sources of emissions and relatively difficult management.China's crude oil imports have increased year by year.Coal-to-liquids have important practical significance and strategic significance.The coal direct liquefaction project is the only coal direct liquefaction plant in the world.The company has not carried out VOCs monitoring and accounting and emission reduction work.The research is of great significance for understanding the emission intensity,emission methods and reducing the VOCs emissions of VOCs in coal direct liquefaction projects.At the same time,it has a strong reference for understanding the emissions of VOCs in the entire coal chemical industry.In this paper,the process flow analysis is carried out for each operation device of the coal direct liquefaction project.According to the whole process engineering and on-site reconnaissance,the equipment is involved in the dynamic and static sealing points of the equipment,organic liquid storage and reconciliation,wastewater,circulating water,combustion fumes,Nine types of VOCs source items for handling,process organization,flare and sampling processes.On this basis,the on-site monitoring is used to collect the relevant process operating parameters of the enterprise,and the corresponding sources are used to calculate the emission source items of VOCs for different source items,and the annual VOCs emissions of the whole plant are calculated to be 897.18 tons.By comparing the emissions of various source items,the discharge ratio of equipment dynamic and static sealing points,organic liquid storage and reconciliation,wastewater and circulating water accounted for 76.3% of the total emissions of enterprises,and the discharge of VOCs representing the direct coal liquefaction project was screened.The four typical source items,by analyzing the factors affecting the emission source of each VOCs,and comparing the same source items of the petrochemical industry,compare the emissions,emission factors and accounting methods of the source items to find out the direct coal liquefaction project.The reason for the difference in emissions from VOCs in typical petrochemical industries is technical support for VOCs emission reduction and control of coal direct liquefaction projects.Finally,based on the control thoughts of the whole process of VOCs,based on the particularity and complexity of coal-to-liquids,combined with the problems found in the field,it is proposed from the aspects of source reduction,process control,terminal management,and accelerated establishment of enterprise VOCs management system.VOCs reduction program for coal direct liquefaction projects.