Kinetic study on the pyrolysis of low-density polyethylene (LDPE) waste using kaolin as catalyst

Abstract

The increase in the industrial and urban activities has resulted in the rise of plastic production and consumption. The higher demand for plastic causes accumulation of plastic waste in which it contributes to environmental problems. About 65-70% of plastic waste is a type of Low-Density Polyethylene (LDPE). To reduce this type of waste, the pyrolysis method can be an alternative. This study investigated the catalyst ratio and particle size of the material. The results indicate that the optimum catalyst was at 15% wt/wt with liquid and gas yields of 99.15% and 0.85%, respectively. Meanwhile, the optimum particle size variation is at 7.5 x 6.5 cm with liquid and gas yields of 99.82% and gas 0.18%, respectively. The proximate analysis of LDPE wastes includes the analysis of ash content, volatile matter, and fixed carbon, with the values of 0.35, 99.61 and 0.04% wt/wt, respectively. The chemical composition is analyzed using Shimadzu GCMS-QP2010S. The highest percentage component is heptane. The fuel analysis shows pyrolysis oil products comply with the national standard set by the regulation No. 14499 KJ14/DJM/2008. The reaction kinetics parameters of the liquid and gas activation energy are of 127,025.79 J/mol and 73,766.93 J/mol, respectively. Meanwhile, the liquid and gas pre-exponential factors are 8,590 and 257,respectively.