Catalytic Conversion of Waste Low Density Polyethylene into Valuable Products

Abstract

Waste low density polyethylene (LDPE) from household and industries are recognized to be a major environmental problem. LDPE represent a source of energy and valuable chemical products. Waste LDPE were pyrolysed catalytically in a batch reactor under atmospheric pressure. Calcium carbide was used as a catalyst to explore its effect on pyrolysis product distribution. The effects of temperature, amount of catalyst and time on the yields of the pyrolysed products were investigated. The effect of catalyst on the liquid yield was also studied. The results demonstrate that the temperature has a promising effect on the yield; however, high temperature, as well as high catalyst loading, caused a decline in liquid yield. The liquid obtained from catalytic pyrolysis of polyethylene was characterized physically by Density, Specific gravity, API gravity, Viscosity, Kinematic viscosity, Aniline point, Flash point, Watson characterization constant, Freezing point, Diesel index, Refractive Index, Gross calorific value, Net calorific value and ASTM Distillation were determined according to IP and ASTM standard methods for determination of fuel values. Results from the physical analysis of the liquid fractions are comparable with the standards used (gasoline, kerosene and diesel fuel oil). Phenols and carbonyls were also quantitatively determined by spectrophotometric methods using folin-denis and phenyl hydrazine reagents, respectively. The components of different hydrocarbons in the oil mixture were separated by using column chromatography and fractional distillation.