Study On Migration Law Of Mercury Speciation During Coal Pyrolysis And Coking

With the rapid development of iron and steel industry and the improvement of related theory,mercury in metallurgical process is gradually paid attention to by people.Although the content of trace element mercury and its compounds is low,it will cause serious pollution to the ecological environment because of its large emission base,and the most important thing is the harm to organisms,which will directly affect human health.At present,with the strengthening of people's awareness of environmental protection and the attention to the quality of living environment,China's research on the emission of trace mercury has become more and more important,and it has become a new topic in the control of environmental pollution.Iron and steel industry as a major emitter of trace elements,the exploration and research is particularly important and urgent..This paper expounds the important position of China's energy structure in coal,and then summarizes the mercury-related knowledge,from the occurrence state of mercury in coal,physics and chemistry,pollution to the existing research status of mercury removal technology.Secondly,the migration and speciation of mercury in oxidizing and reducing atmospheres are predicted by Factsage.It was found that in the pyrolysis range of high temperature,mercury almost completely separated out and entered the gas phase,and nearly 100%of mercury existed as mercury elemental substance.In oxidizing atmosphere and low temperature,as long as the existence of chlorine element,most of mercury element and chlorine element combined to form HgCl₂,and the combination of mercury and sulfur was more difficult than that of mercury and chlorine.Finally,the simulation coking experiment and coal pyrolysis experiment were carried out.The transport behavior of mercury in coal was studied.Mobility of mercury to gas and coke was 58.5%and 28.2%respectively.Most of mercury in coal was transported to gas and coke.During coal pyrolysis,both temperature and isothermal time affect the mercury speciation,but at higher pyrolysis temperature,the length of isothermal time has little effect on the mercury release rate from coal.With the increase of temperature,mercury in coal basically separates out and volatilizes into gas phase.Figure38;Table16;Reference 93.