Progress in the study of chlorine occurrence and release characteristics in coal
Chlorine is one of the harmful trace elements in coal.With the development and utilization of high-chlo-rine coal in Xinjiang,many problems such as fouling and slagging corrosion of heating surface,environmental pollu-tion and harm to human health caused by chlorine in coal have attracted much attention.Therefore,understanding the occurrence state and release characteristics of chlorine in coal is the premise of realizing efficient and clean utiliza-tion of high-chlorine coal.The source,distribution and occurrence state of chlorine in coal are summarized,and the influence of external factors such as atmosphere,temperature and coal quality characteristics on chlorine release char-acteristics in coal thermal process was analyzed.The suggestions for future research on the occurrence and release characteristics of chlorine were provided.The results indicate that the source of chlorine in coal is closely related to groundwater,and the vast majority of coal mines in China belongs to low chlorine coal or ultra-low chlorine coal;Chlorine in coal exists in two existing states:inorganic chlorine and organic chlorine,the inorganic chlorine mainly includes inorganic chlorine ions,water and ions,chloride-containing halide minerals and other chloride-containing impurity minerals.The organic chlorine mainly includes ion exchange state,covalent bond state,other organic chlo-rides and organic ion complexes.The chlorine release characteristics of coal are affected by atmosphere,tempera-ture,coal quality characteristics,heating rate,pressure and other factors.Different atmospheres have different pro-motion and inhibition effects on chlorine release from coal.Organic chlorine and some inorganic chlorine are mainly released in the middle and low temperature range,inorganic chlorine salts are mainly released in the high temperature range,chlorine release forms in coal mainly include HCl,Cl2,NaCl,etc.,and chlorine in different forms can be transformed into each other.It is suggested that new characterization methods for chlorine in coal should be studied in the future,the influence of other components and external factors on chlorine release characteristics should be fully considered,and the internal mechanism of chlorine release in coal should be studied in depth.
万方数据
维普
