Catalytic hydrocracking of used polystyrene

Abstract

Hydrocracking reactions of used polystyrene were performed with varying dual function catalysts (Ni/Sn/F on molecular sieve, Co/Sn/F on molecular sieve, Fe/Sn/F on molecular sieve and Fe/Sn/F on alumina catalysts). The variations were in the temperature, 325-350℃, catalyst concentration, 5-40% wt, hydrogen pressure, 350-500 psig for 1-3 hours and nitrogen pressure, 50-150 psig for 5-6 hours. The optimum catalyst type was Fe(5%)/Sn(5%)/F(2%) on molecular sieve that was a new catalyst type. The optimum conditions for hydrocracking of used polystyrene were an operating temperature of 350℃, 15% wt of catalyst and 400 psig hydrogen pressure for 1.5 hours. The optimum conditions for cracking of used polystyrene were a temperature of 350℃, 10% wt of catalyst and under 100 psig nitrogen pressure for 6 hours. The products from both conditions were liquid hydrocarbons that ethylbenzene was the main component and toluene and iso-propylbenzene were the second and third components.