Pyrolysis of waste expanded polystyrene and reduction of styrene via in-situ multiphase pyrolysis of product oil for the production of fuel range hydrocarbons

[Display omitted] •WEPS was successfully converted to valuable fuel oil.•Developed process significantly reduced the styrene content of liquid oil.•AB-Type/multiphase catalytic process enhanced quality of product oil.•Product oil is suitable for IC engine and generator set applications. Upgraded fuel oil was produced from the waste expanded polystyrene (WEPS) using pyrolysis and in-situ selective aromatization in a specially designed reactor. The catalytic pyrolysis of WEPS was performed keeping the catalyst in three different types of catalyst arrangements inside the reactor i.e., A-type/catalyst in liquid phase, B-type/catalyst in vapour phase, and AB-type or Multiphase/catalyst in both liquid and vapour phases, respectively. The ZSM-5 ammonium powder was used as a catalyst with varying feed to catalyst ratio and 20:1 was found to be optimum. Aromatics of fuel range like benzene, toluene, and ethylbenzene (BTE) were significantly increased and styrene got reduced by many folds when AB-type/multiphase catalytic pyrolysis was performed. The thermal pyrolysis produced maximum liquid yield of 94.37 wt% at a temperature of 650 °C and a heating rate of 15 °C/min. The maximum liquid yield of 88.05 wt%, 78.85 wt%, and 75.11 wt% were obtained for the A-type, B-type, and AB-type catalytic pyrolysis at the temperature of 600 °C, 550 °C and 550 °C, respectively using the same heating rate. The liquid oil of thermal pyrolysis contains very low amount of fuel range aromatics i.e., BTE of 11.38 wt% and the highest amount of styrene (84.74 wt%). In contrarily, BTE content for the catalytic process increased progressively in the order of 18.98 wt% (A-type)