Studies on process optimization for production of liquid fuels from waste plastics

The present work involves the study of process optimization for the production of liquid fuel by the catalytic pyrolysis of different plastics waste such as polypropylene, low density polyethylene and polystyrene using kaolin and acid treated kaolin as catalyst in a laboratory batch reactor. The effect of silica alumina, which has been extensively studied by different investigators for the pyrolysis of different plastics was also studied and compared with that of the catalytic performance of kaolin. From the experimental results, it is found that kaolin is found to be suitable as a catalyst for the degradation of plastics waste to liquid fuel and valuable chemicals. However, silica alumina show superior performance compared to kaolin in terms of yield and reaction time. From the optimization study it is found that, the maximum oil yield in thermal pyrolysis of polypropylene, low density polyethylene and polystyrene waste was 82.5wt.%, 71.5wt.% and 93wt.% at optimum condition of temperature, which is improved to 87.5wt.%, 79.5wt.% and 94.5wt.% respectively in kaolin catalysed degradation under optimum condition of temperature and feed ratio. The rate of reaction, oil yield and quality of oil obtained in the catalytic pyrolysis are significantly improved compared to thermal pyrolysis.