CLEAN COAL AND GAS TO FUELS EXPERIMENTS STUDY ON COAL TAR PYROLYSIS IN THERMAL PLASMA

摘要

The pyrolysis of coal tar using thermal plasma provides a direct and cleaner route to produce acetylene with low hazardous emission,since the ultra high temperatures and concentrated active species in thermal plasma can easily decompose solid/liquid/gas feedstockinto smaller molecules. Experiments were carried out in a lab-scale thermal plasma test platform to investigate the effects of keyoperating conditions including the plasma atmosphere, coal tar feeding method, and coal tar specific enthalpy on the performance ofcoal tar pyrolysis. The results demonstrated that coal tar can be rapidly cracked to acetylene, methane, carbon monoxide, and otherlight gases in the thermal plasma reactor. The higher specific input power of coal tar leads to higher coal tar conversion and acetyleneyield. The increased hydrogen concentrations in plasma working gases enhance the coal tar conversion, and improve the yields ofacetylene. More than 70% coal tar conversions and 25% acetylene yields can be obtained in the experiments. In addition, the mixingefficiency of coal tar and plasma jet is the key to guarantee the coal tar conversion and yield of light gases, which also has directimpact on the coking phenomenon during the reactions.