Influence of catalyst properties on the cracking of polyolefin pyrolysis waxes

This study evaluates the effect of the catalyst acidity and composition (mixtures of base HY catalyst and HZSM-5 catalysts of different acidities) on the catalytic cracking of polyolefin pyrolysis waxes under standard refinery FCC conditions. The experiments have been carried out in a riser simulator, in the 500-550°C range. The results show that the yields and composition of product stream are acceptable and controllable by refineries without any special adaptation of process conditions. The acidity of the catalysts based on HY zeolites has a relevant effect on hydrogen transfer capacity, which contributes to decreasing the concentration of olefins in the gases and in the gasoline. The incorporation of HZSM-5 zeolite is very efficient for increasing the yield of gasoline. This gasoline and LPG are more olefinic than with those obtained with the base catalyst, given that hydrogen transfer capacity of the catalyst is inhibited.