Thermo-catalytic degradation of thermocol waste to value added liquid products

Abstract

Kaoline clay and amorphous silica alumina have been studied as catalysts in the degradation of waste Thermocol (Expanded polystyrene) in a stainless steel autoclave surrounded by a furnace at different temperatures ranging from 350-5500C under partial oxidation condition. The major fraction of the pyrolysis reaction is an oily liquid, which is highly volatile. The reaction time decreased and the yield of liquid fraction increased with the increase in temperature. In the pyrolysis optimization studies, the highest yield of liquid product obtained is 93% in thermal and 94.5% in presence of clay catalyst at 5000C with 1:10 catalyst to plastic ratio. Kaoline clay shows a slight increase in liquid yield whereas silica alumina gives the same with regard to the thermal cracking. The liquid product has been analysed using fourier transformation infrared spectroscopy and detailed hydrocarbon analyser. In addition to styrene the other major products present in the liquid fraction are benzene, ethyl benzene, toluene and methyl styrene. In thermal pyrolysis the amount of styrene is 78%. Both the catalysts altered the product distribution and out of the two catalysts tested, silica-alumina show the highest yield of ethyl benzene and the lowest one of styrene.