Thermal arc plasma gasification of waste glycerol to syngas

Abstract

In this experimental study, waste glycerol gasification to syngas was investigated by utilizing direct current thermal arc plasma of 46–62 kW power. Two gasifying mediums were used: water vapor and air. The plasma-chemical reactor capacity exceeded up to 39 kg/h. Glycerol gasification to synthesis gas process was evaluated in terms of the H2/CO ratio, H2 and CO yield, energy conversion efficiency, carbon conversion efficiency, and specific energy requirements. Experimental results were compared between and also with other research work. Water vapor used as the main gasifying medium for waste glycerol utilization to syngas demonstrated a higher process performance over the air used. Full waste glycerol conversion to synthesis gas was achieved for the case of water vapor, whereas that in the case of air gasification only 75.7%. The lower heating value of the produced syngas exceeded 9.82 MJ/Nm3 and 7.32 MJ/Nm3 for the water vapor plasma and air plasma gasification, respectively. The energy conversion efficiency was calculated to be higher for the water vapor used as a gasifying agent exceeding 63.86%, whereas that of the air plasma gasification only 43.64%. The specific energy consumption required to treat one kilogram of waste glycerol in the environment of water vapor plasma accounted to 191.6 kJ/mol and 266.45 kJ/mol for the air plasma treatment. As conclusion, it was demonstrated that syngas can be successfully produced from waste glycerol by both water vapor and air plasma gasification. However, the use of water vapor as a gasifying agent gave a better process efficiency over the air in all the parameters studied.