Product composition and coke deposition in the hydrocracking of polystyrene blended with vacuum gasoil

Abstract The upgrading of polystyrene (PS) together with vacuum gasoil (VGO) by means of hydrocracking has been investigated. The aim of the work has consisted on explaining, based on the hydrocracking mechanism, the effects of the co-feeding and of the operating conditions on products distribution and catalyst deactivation. For this purpose hydrocracking tests have been carried out in a batch reactor for a PS/VGO blend (10/90 in mass) under the following conditions: 380–420 °C; 80 bar; contact time, 30–300 min; and C/O ratio, 0.1 gcatalyst goil−1. The liquid products have been extensively characterized by chromatographic means, exposing that the naphtha and LCO (light cycle oil) fractions produced at 400 and 420 °C are suitable to be used in the blending of automotive fuels. Finally, coke fraction has been characterized by different techniques exposing that at low temperature the PS has a strong influence on catalyst deactivation, whereas at high temperature its effects are not so notably. Thus, the results expose that by co-feeding PS to a hydrocracking unit, it can effectively be converted it into streams of interest for refinery without causing any operational issue.