Optimal plasma torch forms and operating parameters for ignition energy minimization and coal ignition stabilization

The paper presents the results of experimental and computational study determining optimal shapes and operating parameters of a plasma torch that minimize ignition energy and maximize combustion front stabilization for low grade brown coals. Two types of plasma torches were studied – a direct-flow torch and a vortex torch. It was found that the vortex design, due to its developed contact surface, reduces required power for stable ignition from 180 to 120 kW, minimum dust concentration from 0,8 to 0,6 kg/kg, and mixing time by 30–40 %. The study determines optimal parameters for coals from the Kharanor, Tataurovo, Urutuy, and Okino-Klyuchi deposits: vortex torch, power 120–150 kW, dust concentration 0.6 kg/kg, and air-fuel mixture flow rate 2800–4200 m³/h.