Production of Synthesis Gas from Coal by DC Non-Transferred Steam Plasma Gasification System

The purpose of this study is to investigate coal gasification for the production of synthesis gas (syngas) using a non-transferred steam plasma system. The effects of the coal feeding rate on cold gas efficiency, carbon conversion, and hydrogen conversion were evaluated by the amount of syngas from two kinds of coals. Coal I is a low grade coal which has high moisture content and Coal II is a high grade coal which has high lower heating value (LHV) and low moisture content. The coal feeding rate was varied from 12.5 to 34.1 kg/h. Carbon to oxygen ratios were changed from 0.3 to 0.8 for Coal I and 0.5 to 1.2 for Coal II, respectively. For plasma forming gas, steam was supplied at 23 kg/h. Carbon conversion, hydrogen conversion, and cold gas efficiency were decreased with increasing the coal feeding rate. Coal II exhibits a higher syngas composition in produced gas than Coal I, which does not easily participate in the gasification reaction due to high moisture content. In the case of Coal II, the highest syngas ratio in produced gas, cold gas efficiency, and LHV were 89.0%, 58.2% and 11.4 MJ/m3, respectively.