Co-gasification of plastic-biomass mixtures for hydrogen production

In this study, the gasification of sorghum biomass (SB) with PET, HDPE, PP, and PVC, both individually and in combination, was investigated using two different reactor types: a closed-system batch-type reactor and a fixed-bed reactor operating under atmospheric conditions. The objective of the study was to achieve maximum total gas and hydrogen yield. Within this scope, the effects of temperature, catalyst type, use of an organic solvent, and plastic/SB and feedstock/water ratios were evaluated, and optimal conditions were determined. In the co-gasification experiments conducted in the batch reactor, the highest hydrogen yield of 20.3 mol H2/kg was observed when 3% KCl catalyst was used in the SB/PVC mixture. When the SB/PET mixture was gasified using dual catalysts (K2CO3/CaO and KOH/CaO), gas products containing less than 1% CO2 and over 90% H2 were obtained.In an atmospheric fixed-bed reactor, the highest total gas volume and H2 yield were obtained with PVC (1186 ± 39 mL; 75.9 ± 0.6% H2) and SB/PVC (1490 ± 34 mL; 66.4 ± 0.5% H2), respectively. Additionally, the use of auxiliary organic solvents such as glycerol, THF, and phenol significantly increased hydrogen production.