Co-cracking of atmospheric residue and plastic waste

Abstract

The processing of residual fractions after the distillation of oil and waste plastics into fuels is an important aspect from environmental, energetic and economic points of view. However, current methods of their processing are not effective enough for widespread implementation. In this work the effect of the addition of polyethylene terephthalate (PET), low-density polyethylene (LDPE) and polypropylene (PP) to the atmospheric residue on the composition of final products of subsequent cracking is investigated. It has been established that addition of PET to the atmospheric residue has a positive effect on the yield of light fractions and the destruction of resin-asphaltene substances (RAS) in comparison with cracking of atmospheric residue (AR) only. After cracking with the PET additive, the additional yield of light fractions is 4.8 wt%. It has been shown that PET affects the amount and structure of coke resulted from the cracking of atmospheric residue. A positive effect of the PP additive on the destruction of RAS is also revealed. In particular, the content of asphaltenes is lowered by a factor equal to 9.8 compared to that in the liquid products after fuel oil cracking. It has been also found out that polypropylene 1.7 times more than PET and 1.5 times more than PE enhances additional coke formation. It is shown that LDPE has the least positive effect from co-cracking with AR compared to the case with PET and PP. A hypothetical mechanism is presented for the interaction of PET, LDPE, and PP with AR during co-cracking.