Production of Fuel Oil from Municipal Plastic Wastes Using Thermal and Catalytic Pyrolysis

Abstract

Plastics have become an essential part of modern life today. The global production of plastics has gone up to 299 million tonnes in 2013, which has increased enormously in the present years. The utilization of plastics and its final disposal pose tremendous negative significant impacts on the environment. The present study aimed to investigate the thermal and catalytic pyrolysis for the production of fuel oil from the polyethene plastic wastes. The samples collection for both plastic wastes and clay catalyst, sample preparation and pyrolysis experiment for oil production was done in Laroo Division, Gulu Municipality, Northern Uganda Region, Uganda. Catalysts used in the experiment were acid-activated clay mineral and aluminium chlorides on activated carbon. The clay mineral was activated by refluxing it with 6M Sulphuric acid for 3 hours. The experiment was conducted in three different phases: The first phase of the experiment was done without a catalyst (purely thermal pyrolysis). The second phase involves the use of acid-activated clay mineral. The third phase was done using aluminium chlorides on activated carbon. Both phases were done at different heating rates. In purely thermal pyrolysis, 88 mL of oil was obtained at a maximum temperature of 39ºC and heating rates of 12.55ºC /minute and reaction time of 4 hours. Acid activated clay mineral yielded 100 mL of oil with the heating rates of 12.55ºC/minute and reaction time of 3 hours 30 minutes. While aluminium chlorides on activated carbon produced 105 mL of oil at a maximum temperature of 400ºC and heating rates of 15.5ºC /minute and reaction time of 3 hours 10 minutes. From the experimental results, catalytic pyrolysis is more efficient than purely thermal pyrolysis and homogenous catalysis (aluminium chlorides) shows a better result than solid acid catalyst (activated clay minerals) hence saving the energy needed for pyrolysis and making the process more economically feasible.