Gasification of pellets produced from blends of biomass wastes and refuse derived fuel chars

Abstract

Refuse derived fuel (RDF) was carbonized at 300 °C for 30 min and the resulting RDF char was used as additive for biomass pellets. Pine waste pellets with 0, 5 and 10% incorporation of RDF char were prepared and characterized. RDF char incorporation caused an increase in fixed carbon and ash contents of the pellets. The pellets were subjected to gasification in a 1 kg/h bubbling-fluidized-bed gasifier at different temperatures (800 and 850 °C) and equivalence ratios (0.25 and 0.30). The producer gas yield varied from 1.5 to 2.5 m3/kg and was higher for an ER of 0.25. Carbon conversion and cold gas efficiency presented values between 60.4% - 96.1% and 42.3%-73.7%, respectively. Concentrations of CO, CO2, H2 and CH4 reached values between 13.3-17.4 vol% dry for CO, 13.1-14.7 vol% dry for CO2, 4.9-11.1 vol% dry for H2 and 3.5-4.4 vol% dry for CH4. Tars produced during gasification contained mainly aromatic hydrocarbons and phenols, showing an increase in heavy PAHs concentration with higher RDF char incorporation. The RDF char can be used as a gasification additive at moderate incorporation ratios.