(432a) Catalytic Co-Pyrolysis of Microalgae and Low Density Polyethylene Waste to Aromatic Hydrocarbons Using Activated Carbon

Catalytic and non-catalytic fast co-pyrolysis of micro algae (chlorella spp) and low density polyethylene (LDPE) waste were studied in multi-shot pyrolyzer using activated carbon as catalyst. Dried microalgae was co-pyrolyzed with LDPE in both the presence and absence of activated carbon to investigate the interaction between algae and LDPE during thermal decomposition and catalytic upgrade of the pyrolysis vapor. The TGA analysis of co-pyrolysis of the two feedstocks show initial temperature of active pyrolysis decreased in co-pyrolysis compared with that in microalgae and LDPE individual pyrolysis, which indicates that co-pyrolysis can start at lower temperature than individual pyrolysis. In the non-catalytic co-pyrolysis study in micro-pyrolyzer-GC/MS, the results indicated the interaction between microalgae and LDPE during co-pyrolysis had a pronounce effect on both microalgae derived oxygenated compounds and C₁₀-C₂₀ aliphatic hydrocarbons from the depolymerization of LDPE. The total oxygenated compounds (mainly carbohydrate and lipid derived) increased by 18.7 % whiles olefins and alkanes saw an increase of 6.9% and 14.2% respectively. Results indicated that aromatic and aliphatic hydrocarbons were the major product produced from the catalytic pyrolysis of Algae/Activated Carbon, Algae-LDPE/Activated carbon and LDPE/Activated carbon at all temperatures. The pyrolysis of algae produced relatively small aromatic hydrocarbons whilst pyrolysis of LDPE produced aromatic hydrocarbons with high yield at increasing temperatures. Addition of Algae to LDPE increased the yield of total aromatic hydrocarbons in Algae/LDPE/catalyst (an increase of 71.8% from 600^oC to 700^oC) compared to Algae/catalyst alone (an increase of 12.7% from 600^oC to 700^oC) and LDPE/catalyst alone (an increase of 6.1% from 600^oC to 700^oC) indicating high synergetic effect at rather higher temperature.