High-Temperature Plasma-Chemical Conversion of Low-Grade Coal and Hydrocarbon Gases into Synthesis Gas and Value-Added Products

This study presents an experimental evaluation of plasma-chemical technologies for converting low-grade coals and hydrocarbon gases into valuable products. High-temperature plasma-assisted processes, including gasification, hydrogenation, and cracking, were investigated using an industrial-scale electric arc reactor capable of operating at temperatures up to 3200 K. Plasma-steam gasification experiments achieved carbon conversion of 98.3% and synthesis gas yields with combined CO and H2 concentrations exceeding 95%. Plasma hydrogenation at 3000–3200 K produced gas mixtures containing up to 38.7% acetylene and 19.5% ethylene, confirming the efficiency of direct coal conversion to unsaturated hydrocarbons. Plasma cracking of hydrocarbon gases produced hydrogen concentrations up to 24% and the formation of highly dispersed technical carbon with a specific surface area of 450 m²/g and over 70% nanotube content. The energy consumption for gasification was as low as 1.8 kWh/kg, demonstrating a significant reduction compared to conventional technologies. The results highlight the technological and environmental advantages of plasma-chemical processing in achieving deep conversion of carbonaceous feedstocks with reduced emissions and high-value product recovery.