Circular economy for plastic waste to polypropylene via refinery FCC and alkylation units

A continuous process for converting waste plastic into recycle for polypropylene polymerization comprising:

• (a) selecting waste plastics containing polyethylene and/or polypropylene with the waste plastics containing less than 5 wt % of polyethylene terephthalate and polyvinyl chloride;
• (b) passing the waste plastics from (a) through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent;
• (c) separating the pyrolyzed effluent into offgas, a naphtha/diesel fraction, a heavy fraction, and char;
• (d) passing a pyrolysis oil and optionally wax comprising the naphtha/diesel fraction and the heavy fraction to a refinery FCC unit with the volume flow of pyrolysis oil and wax to the FCC unit comprising up to but no more than about 50 volume % of the total hydrocarbon flow to the FCC unit;
• (e) recovering a liquid petroleum gas comprising a C3-C5 olefin/paraffin mixture from the FCC unit;
• (f) passing the liquid petroleum gas fraction to a refinery alkylation unit;
• (g) recovering a propane fraction from the alkylation unit;
• and
• (h) passing the propane fraction to a dehydrogenation unit to produce propylene.