Behavior of chlorine during co-carbonization of coal and chloride compounds in cokemaking process

Abstract

The behavior of chlorine during co-carbonization of coal and chloride compounds such as PVC in cokemaking process both on a laboratory scale and commercial scale was investigated. On a laboratory scale test, the chlorine residue ratio in coke derived from PVC was only 0.04%, which was much lower than that derived from the coal tested (35.1%) and NaCl (52.9%). The chlorine residue ratio derived from PVC reached near zero at about 400°C and it decreased at lower temperature range than that derived from MgCl2, NaCl and CaCl2. CaO addition helped the chloride derived from coal, PVC and NaCl to be fixed in coke. In the commercial scale coke oven, the addition of PVC to coal hardly affected the chlorine content in coke and COG. Most of the released chlorine was absorbed by the ammonia liquor spray for cooling hot COG. The chlorine in PVC was distributed to the coke, the ammonia liquor and the COG by 7%, 92% and 1% respectively, while the chlorine in coal was distributed by 43%, 56% and 1% respectively. The chlorine residue ratio in coke derived from PVC was much lower than that derived from coal since the decomposition of PVC added to coal was much faster than the release of chlorine from coal during carbonization.