Fuel production by cracking of polyolefins pyrolysis waxes under fluid catalytic cracking (FCC) operating conditions

Abstract

The catalytic cracking of high–density polyethylene pyrolysis waxes under fluidized catalytic cracking conditions has been investigated with the aim of producing fuels at large–scale from waxes obtained in pyrolysis plants located nearby collection and segregation points. Additionally, preliminary information about the capacity of these units to valorize waste polyolefins has been obtained. The catalytic cracking runs have been performed in a riser simulator reactor under industrial conditions: 500–560 °C; catalyst to oil mass ratio, 3, 5 and 7 gcat goil−1; and, contact time, 6 s. The product distribution has been quantified determining the yields of different fractions, which have been defined according to their boiling point range: dry gas, liquefied petroleum gas, naphtha, light cycle oil, heavy cycle oil and coke. The concentration of the families of compounds has been also determined, which are n–paraffins, iso–paraffins, olefins, naphthenes and aromatics. For the shake of comparison, the results of catalytic cracking of a common stream fed to the industrial units, i.e., vacuum gasoil, have been included. Globally, promising results have been obtained in the valorization of waste polyolefins by means of this combination of pyrolysis–cracking stages that expose, at the same time, the capacity of this unit to manage waste plastics.