Co-gasification of plastics waste and biomass in a pilot scale fluidized bed reactor

Co-gasification tests were carried out in a pilot scale bubbling fluidized bed gasifier, large enough to exclude any scale-up effect, and able to treat up to 100 kg/h of plastics and biomass mixtures. It was operated under chemical and thermal steady-state, with equivalence ratios varying from 0.19 to 0.28, and plastics/biomass blending ratios from mono gasification of plastics to that of biomass. The results are reported in terms of main process per-formance parameters and axial profiles of syngas composition and reactor temperature. They indicate that plastics/biomass ratio and equivalence ratio remarkably affect the gasifier performances, even though the ob-tained syngas was always of rather good quality, with a low heating value between 7 and 10 MJ/m3N. The axial syngas compositions showed a monotonic reduction of carbon dioxide concentration (of about 20-30%) and a corresponding increase of hydrogen concentration (of about 90-110%), highlighting the key role of water gas shift, and steam and dry reforming reactions. The overall set of results provides information about the feasibility of co-gasification of plastics waste and biomass at a demonstration scale and supports the optimisation of design or operating criteria as well as the implementation of reliable numerical models of bubbling fluidized bed gasifiers.