Catalytic co-pyrolysis of Eichhornia Crassipes biomaѕѕ and polyethylene using waste Fe and CaCO₃catalysts

Abstract

A wild aquatic plant, Eichhornia Crassipes, and polyethylene have been converted into liquid product thermo-catalytically and cost effectively through co-pyrolysis using batch steel pyrolyzer. The Fe and CaCO3 catalysts were obtained as wastes from various mechanical processes. The catalytic process was compared with non-catalytic pyrolysis. The effect of various reaction conditions was investigated in order to find out the optimized process conditions. It was found that the favorable reaction conditions were 450 °C temperature and 1-h reaction time at a heating rate of 1 °C/s and 0.4-mm biomass particle size. The bio-oil yield was found to be 34.4% and 26.6% using Fe and CaCO3 respectively with catalysts particle size of 0.4 mm at the optimized reaction conditions and 5 wt% of biomass. The non-catalytic and catalytic co-pyrolysis using Fe as catalyst produced 23.9% and 28.7% oil respectively. Thus the efficiency of processes in terms of bio-oil production was found in order of: Fe > CaCO3 > non-catalytic pyrolysis. The GC/MS analysis of n-hexane extract of bio-oil shows that Fe catalyst favors formation of aliphatic hydrocarbons while CaCO3 and non-catalytic pyrolysis favors formation of aromatic hydrocarbons. Mostly unsaturated aliphatic hydrocarbons were formed in case of co-pyrolysis reactions. The calorific value of bio-oil was also measured in order to find out the fuel properties of the products. Copyright © 2016 John Wiley & Sons, Ltd.