An improved gravimetric method applied to co-processing of polyethylene terephtalate and petroleum blend using HY zeolite as a catalyst

The co-processing of petroleum and polyethylene terephthalate (PET) was carried out in the presence and absence of a catalyst in an open vessel batch reactor at temperatures of 200, 300, 400, and 500 degrees C, which corresponds to temperatures of distillation and cracking. The catalyst used was the acidic HY zeolite, which is widely used in petroleum refining. The catalytic co-processing was carried out with the PET-oil charge, at a mass ratio of 1:1, containing 10% of HY zeolite. The conversion degree was measured by knowing the initial sample mass and amount of degraded material for each temperature and reaction time, using an improved gravimetric method consisting of a precision balance and an oven with a heating rate controller. The conversion values obtained were compared for petroleum and PET samples with and without the zeolite catalyst. At temperatures of 200 and 300 degrees C, the PET showed low conversions, about 5-10%. However, for the catalytic co-processing of PET-oil/HY at these same temperatures, an increase in conversion to about 25-30% was observed. At temperatures of 400 and 500 degrees C, conversions above 90% were obtained for the two samples, with a subsequent reduction in the activation energy, from 76kJ mol(-1) (PET) to 56kJ mol(-1) (PET-oil/HY). The decrease in the activation energy proved the efficiency of the HY zeolite and the synergistic effect when PET was blended to the oil for the catalytic co-processing, proving to be a viable alternative for the chemical recycling of PET in the petroleum industry.