关键词: 热解, 煤焦油, 热等离子体, 多相反应, 化学反应器

Abstract: 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 feedstock into smaller molecules. Experiments were carried out in a lab-scale thermal plasma test platform to investigate the effects of key operating conditions including the sample inject temperature, plasma atmosphere, and coal tar specific enthalpy on the performance of coal tar pyrolysis. The results demonstrated that coal tar can be rapidly cracked to acetylene and other light gases in the thermal plasma reactor. The viscosity of coal tar can be decreased by pre-heated, thereby increasing the mix efficiency between coal tar and thermal plasma jet. The increased hydrogen concentration in plasma working gases improves the coal tar conversion and the yield of acetylene, and reduces coking as well. Higher specific input power of coal tar leads to higher coal tar conversion, acetylene yield and the yields of light gases. 86.3% coal tar conversions, 24.6% acetylene yields and 51.7% yield of light gases were obtained in the optimal experiment. In addition, plasma pyrolysis process can generate ethylene as by-products, and the concentration ratio of ethylene to acetylene can be used to predict the gas reaction temperature.

Key words: pyrolysis, coal tar, thermal plasma, multiphase reaction, chemical reactors