CIRCULAR ECONOMY FOR PLASTIC WASTE TO POLYETHYLENE AND CHEMICALS VIA REFINERY CRUDE UNIT

• Main Author: TIMKEN, Hye-Kyung
• Format: Patent
• Language: English; French; German
• Published: 28.02.2024
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; CRACKING HYDROCARBON OILS; DESTRUCTIVE DISTILLATION OF CARBONAGEOUS MATERIALS FORPRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS; FUELS; LUBRICANTS; METALLURGY; MINERAL WAXES; ORGANIC CHEMISTRY; PEAT; PETROLEUM, GAS OR COKE INDUSTRIES; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVEHYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, ORGASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; TECHNICAL GASES CONTAINING CARBON MONOXIDE

Provided is a continuous process for converting waste plastic into recycle for polyethylene polymerization or for normal alpha olefins. The process comprises selecting waste plastics containing polyethylene and/or polypropylene and then passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a naphtha/diesel fraction, a heavy fraction, and char. The naphtha/diesel fraction is passed to a crude unit in a refinery from which is recovered a straight run naphtha fraction (C5-C8) or a propane/butane (C3-C4) fraction. The straight run naphtha fraction, or propane and butane (C3-C4) fraction, is passed to a steam cracker for ethylene production. The ethylene is converted to normal alpha olefin and/or polyethylene. Also, a heavy fraction from the pyrolysis reactor can be combined with a heavy fraction of normal alpha olefin stream recovered from the steam cracker. The combined heavy fraction and heavy fraction of normal alpha olefin stream can be passed to a wax hydrogenation zone to produce wax.