Comparative Study of the Chemical Compositions of Liquid Fuel from Thermal Cracking of Low and High-Density Polyethylene Plastic Waste

Abstract

The increase in the rate of accumulation of plastic waste (PW) has been of great concern to the world especially in the developing countries due to its non-biodegradable nature and improper waste management practices. Hence, efforts towards the conversion of this waste (PW) to resourceful materials have led us to the exploration of pyrolysis (anaerobic thermal cracking) of plastic waste under a controlled condition to produce liquid fuel. A stainless steel batch reactor was used in the cracking of the low and high-density polyethylene (LDPE and HDPE) plastic wastes into liquid fuel components at a temperature of 230°C. The liquid fuel obtained from the pyrolyzed LDPE and HDPE was analyzed using GC-MS. Fifty (50) compounds each was identified for both LDPE and HDPE which revealed the presence of mostly alkenes and aromatics in the hydrocarbon ranges of C8 – C24. This is made up of 36% of gasoline fractions range from C6 – C12, 32% of diesel fractions range C13 – C20, and 14% oil of residual fuel range of C20 – C28 and 18% of non-hydrocarbons was discovered for the HDPE while 36% of gasoline fractions range of C6 – C12, 34% of diesel fractions range C13 – C20, oil and 12% residual fuel range of C20 – C28 and 18 % of non-hydrocarbons was discovered for the LDPE. There is little or no difference in the products of pyrolysis of light and heavy polyethylene plastic waste.