Co-Pyrolysis Studies\nof Agricultural Residue and Plastics\nfor Process Optimization in a Rotary Kiln Reactor System

This research mainly focuses on the co-pyrolysis of agricultural\nbiomass, i.e., groundnut shell (GS) and different plastics such as\nlow-density polyethylene (LDPE), high-density polyethylene (HDPE),\nand polypropylene (PP). Co-pyrolysis studies were conducted in a semi\npilotscale rotary kiln reactor at 500 °C with different biomass\nto plastic ratios (90:10, 70:30, and 40:60). The maximum pyrolytic\noil (Py-oil) yield of 49% was obtained with GS/HDPE in 40:60 ratio,\nwhile the maximum non-condensable gases (NCGs) yield of 36% was obtained\nwith GS/LDPE (40:60). Maximum char yields of up to 38% were observed\nwith pure GS. The yields of py-oil and NCGs. increased with increasing\nplastic ratio, whereas for char, the yield decreased with increasing\nplastic ratio. Elemental analysis of the py-oil showed an increase\nin the carbon and hydrogen content from 59 to 79% and from 7 to 12%,\nrespectively, with increasing plastic content. The higher heating\nvalue (HHV) of py-oil increased from 25 to 43 MJ/kg with the addition\nof plastics to biomass. The chemical composition of the oil also varied\nsignificantly with different blend ratios and depended on the type\nof plastic. Overall, it was observed that by increasing the plastic\nratio, there is a corresponding decrease in phenolics and improvement\nin aromatics (45%), alcohols (20%), and hydrocarbons (35%). The carbon\ncontent in char was found to increase moderately from 72 to 80% with\nan increase in plastic content.