Research On Environmental Risk Identification And Assessment In Coking Industry

The raw materials and products in the coking industry are flammable,explosive,corrosive and toxic.It is easy to bring varying degrees of impact and damage to the environment and people around.With the development of the society,environmental risk assessment plays an more important role in the process of building a coking project and management of a coking plant.This paper analyzed typical environmental risk substance in coking industry and environmental risk process,and environmental risk assessment based on a coking plant in shijiazhuang city was carried out.The main research results were as follows:Difficult problems in environmental risk substance identification process were summarized,and solutions were put forward.environmental risk substances were identified,such as wash oil,coal tar,crude benzene,coke oven gas,sulfuric acid and ammonia.process and risk points of coking industry were introduced.Risks of production system,storage system and transportation system were anlyzed.Combined with hazards of environmental risk substances,curde bezene tank in tank farm and gas pipeline were selected as research object.The determination method of the standard of environmental emergency threshold was as follows:if the final AEGLs exist,AEGLs were used as environmental emergency threshold;If no AEGLs exist or only the interim AEGLs exist,the manimun value of AEGLs,ERPGs and PACs were used as environmental emergency threshold;If part of AEGLs were not recommended,PACs were as supplementary data..For crude benzene and carbon monoxide,the standard of environmental emergency threshold were EET-1(50ppm)?EET-2(150ppm)?EET-3(1000ppm)and EET-1(75 ppm)?EET-2(83ppm)?EET-3(330ppm)respectively.Combined with crude benzene leakage,gas pipeline rupture and secondary diffusion of crude benzene combustion,the author used“the Risk System software”for risking modelling prediction.Taking a coking plant in shijiazhuang city as an example,the author predicted the maximum falling concentration of downwind at different time after the accident,and explored the distribution relationship between the maximum influence of concentration and time and distance after the accident.the maximum falling concentration of downwind decreased as time and distance increased.In the condition of wind speed2.2m·s~-11 and atmospheric stability F,the maximum influence time and distances of crude benzeneleakageaccidentwere22min(EET-2),44min(EET-1)and3950m(EET-2),5493(EET-1)respectively.The maximum influence time and distances of coal gas leakage accident were 21min(EET-2)and 800m(EET-2)respectively.The maximum influence time and distances of secondary diffusion of crude benzene combustion accident were 280min(EET-2)and 440m(EET-2)respectively.