Transformation of biomass and waste plastic mixtures into hydrocarbon oils and gases by pyrolysis using different reactor temperatures and pressures

In this work the laboratory scale pyrolysis and gasification of biomass and plastic waste mixtures were investigated at different temperatures (450°C and 750°C) and reactor pressures (0.1 bar and 1.0 bar). The main decomposition reactions and the effect of the process parameters were followed through the product yields and compositions of gases and pyrolysis oils. Less residue and significantly more gases had been found at higher temperature, which phenomena was more notable in case of higher proportion of plastic waste in the raw material mixtures. The concentration of hydrogen in gases changed by opposite trend at 450°C and 750°C as function of biomass ratios. The hydrogen and CO ratio can also increase by the increasing in plastic proportion of raw materials at both temperatures and pressures. Regarding the pressure, it can increase the pyrolysis and gasification reactions resulted higher yields of gases and lower oil/water ratios. More hydrogen and less C₂-C₆ compounds were found using 0.1 bar reactor pressure. Pyrolysis-oil contained aliphatic and aromatic hydrocarbons; n-paraffin, n-olefin, aldehyde, ketones, alcohols, phenols, carboxylic acids, etc. Due to deoxygenation reactions, hydrocarbons with less oxygen-containing compounds were found at 0.1 bar pressure.