Onsite Conversion of Thermoplastic Waste into Fuel by Catalytic Pyrolysis

Pyrolysis of high density polyethylene (HDPE) waste in the form of carrybags was carried out in an inhouse fabricated glass reactor of one litre capacity. For reaction, waste material of about 200-300 grams was used. An inert atmosphere was created in the reactor by purging nitrogen gas. The maximum temperature in a reactor was kept about 5500C. Reaction was carried out with and without using natural zeolite (NZ) and alumina catalysts. It was found that, time required for completion of the pyrolysis process was 3.5 hrs without catalyst and 2.5 hrs with catalysts. Upon comparison between fuel obtained with and without catalysts, it is observed that in absence of catalyst, process gives about 60-62% yield, with 5 % natural zeolite yield is 65-67 % and with 5 % alumina catalyst it is about 70-71 %. An increase in the yield % and calorific value is observed with both the catalysts but higher effect is seen in case of oil obtained with alumina. Analysis of oil samples by GC-MS showed presence of gasoline, kerosene and diesel fractions (C5-C20) with other high molecular weight fractions from C20-C37 for all systems. Currently there are mechanical systems available for recycling of plastic waste but these systems involve more cost in transportation than recycling. Scaling up of the present method would substantially reduce the transportation cost and would also help in the quest of exploring economically viable recycling system for plastic waste