Downdraft co-gasification of high ash biomass and plastics

Abstract

Co-gasification is gaining attention as a sustainable chemical recycling technology for the conversion of plastic waste and biomass into producer gas. Experimental study of the co-gasification of low density polyethylene waste plastic and garden waste biomass is performed in a downdraft gasifier to understand the viability of using plastic waste with high ash biomass (ash content above 10% w/w) as a feedstock and to investigate the quality of the gas obtained. By increasing the plastic content in the feedstock from 0 % wt. to 25 % wt., an increase of temperature is observed in all zones of the gasifier, improving the lower heating value of the gas produced from 3.5 MJ/Nm3 to 4.7 MJ/Nm3 and increasing the cold gas efficiency from 43.8% to 61.8%. It has also reduced the clinker formation from 3 % wt. to 0.65 % wt. in terms of the feedstock and slightly decreased the tar yield from 8.1 g/Nm3 to 5.7 g/Nm3. Further, by changing the equivalence ratio during the co-gasification, the effect on heating value, energetic yield and gas yield obtained is also reported.