Autothermal downdraft oxy-steam co-gasification of biomass and plastic wastes for hydrogen-rich syngas production: An Aspen plus modelling

The potential of H₂-rich syngas generation using downdraft co-gasification of biomass and plastic wastes is investigated using an autothermal restricted equilibrium study using Aspen Plus. A comprehensive sensitivity analysis is carried out to impart the influence of important process parameters, viz. equivalence ratio(ER: 0.1–0.5), feed plastic content(FPC: 0–30 %), steam to feed ratio(SFR: 0–4) and steam temperature(150–1000 °C) on performance parameters, viz. syngas composition, gasification temperature(GT), lower heating value(LHV), cold gas efficiency(CGE), gasification energy efficiency(GEE) and hydrogen energy efficiency(HEE). The ER and SFR showed dominant effects on performance. The increase in ER from 0.1 to 0.5 causes an increase in GT from 565 °C to 1734 °C. The highest syngas H₂ content and HEE of 52.1 % and 36.9 %, respectively, are obtained for 0.25 ER. The increase in SFR improves the syngas H₂ content at the cost of LHV and GEE, with the highest HEE of 36.9 % obtained at 0.25 ER. The analysis of variance(ANOVA) and response surface methodology(RSM) has also been studied along with the multi-objective optimisation(MOO).