Studies on Solvent-free Direct Liquefaction of E-waste Plastics and its Co-liquefaction with Biomass Waste and High Ash Coal for Liquid Fuel Production

Abstract

Escalating price of the crude oil and its declining resources have augmented the worth of the alternative fuel resources in the global energy sector. Coal, biomass and plastics are the major alternate hydrocarbon feed sources and thermo-chemical treatment like direct liquefaction can be applied for converting such feedstock into alternate liquid hydrocarbon fuels with less energy consumption compared to pyrolysis or gasification to strengthen the energy security. In this context, the present study is focused on direct liquefaction of discarded printer cartridge plastics (DPCP) and co-liquefaction with mesua ferrea seed kernel (MFSK) and high ash coal (HAC). The experiments are performed under milder operating conditions of temperature (325-425℃) and pressure (20 bar initial N2 pressure) for 8-60 min without using any solvent and catalyst. Co-liquefaction of DPCP and MFSK shows higher feed conversion and oil yield of 88.44 wt.% (at 325℃ in 30 min) and 52.83 wt.% (at 350℃ in 15 min), respectively. The kinetic study shows that the Ea required for mixed feed to oil conversion reaction is significantly lowered compared to that in individual plastic liquefaction. The interaction between feed materials during co-liquefaction promotes aliphatic and aromatic hydrocarbons in oil with a carbon chain length of C8-C40. Synergistic effect of co-liquefying DPCP and MFSK is observed in improved calorific value (39.77 MJ/kg), H/C ratio (1.35) and reduced viscosity (9.67 to 4.75 mPa-sec) compared to only DPCP liquefied oil. Synergistic effect of co-liquefying coal/plastic mixture is noticed in the oil quality with enhanced calorific value (from 39.67 to 42.15 MJ/kg), H/C ratio (from 1.21 to 1.29) and dynamic viscosity (from 9.67 to 4.05 mPa-sec) compared to DPCP liquefied oil. Co-liquefied oil obtained from tri-feed co-liquefaction is also found with high calorific value 41.78 MJ/kg and higher H/C ratio 1.63 and lowest dynamic viscosity 3.52 mPa-sec as compared to the other liquefied oil samples. The thesis provides an in-depth understanding of the thermal degradation of various hydrocarbon feedstock and possible interactions through direct liquefaction and co-liquefaction. Use of cheaper materials like electronic waste plastics, waste biomass and low rank coals provide potential alternative strategy to make the direct liquefaction technology cost effective and feasible for large scale operations.