Conversion of plastics to monomers with integrated recovery with a cracking unit

Patent metadata

Field	Value
Publication number	US-2022010211-A1
Application number	US-202117360657-A
Country	US
Kind code	A1
Filing date	Jun 28, 2021
Priority date	Jul 11, 2020
Publication date	Jan 13, 2022
Grant date	—

Abstract

A plastic pyrolysis process produces light olefin product and heavier products. The light olefin products are separated in a recovery process while the heavier product can be sent to a cracking unit to be further cracked to desired products. The cracked effluent stream may be subjected to the recovery process along with the light olefin product.

First claim

1 . A process for converting plastics to monomers comprising:
heating a plastic feed stream to a temperature of about 300 to about 1100° C. to pyrolyze the plastic feed stream to a pyrolysis product stream including monomers; separating said pyrolysis product stream into a gaseous pyrolysis product stream and a liquid pyrolysis product stream; recovering monomers from said gaseous pyrolysis product stream; and taking a cracking unit feed stream from said liquid pyrolysis product stream; and feeding said cracking unit feed stream to a cracking unit.

2 . The process of claim 1 further comprising producing a cracking effluent stream from said cracking unit and recovering monomers from said cracking effluent stream and said gaseous pyrolysis stream together.

3 . The process of claim 2 further comprising fractionating said liquid pyrolysis product stream to provide a fractionated overhead and a fractionated bottoms stream and taking said cracking unit feed stream from said fractionated bottoms stream.

4 . The process of claim 3 further comprising recovering monomers from said fractionated overhead stream with said gaseous stream pyrolysis product stream.

5 . The process of claim 3 wherein said fractionating is performed in a depentanizer column and further comprising fractionating said fractionated bottom stream in a hexene column to provide a hexene column overhead product comprising 1-hexene and a hexene column bottoms product comprising nC 6+ hydrocarbons and taking said cracking unit feed stream from said hexene column bottoms product.

6 . The process of claim 1 wherein said heating step is conducted at a temperature of about 600 to about 1100° C. to produce a high-temperature pyrolysis product stream and further comprising quenching said high-temperature pyrolysis product stream to provide said gaseous pyrolysis product stream and said liquid pyrolysis product stream.

7 . The process of claim 6 further comprising compressing said gaseous pyrolysis product stream prior to recovering monomers from it.

8 . The process of claim 2 further comprising fractionating said gaseous pyrolysis product stream, said cracking effluent stream and said gaseous pyrolysis product stream together.

9 . The process of claim 8 further comprising fractionating said gaseous pyrolysis product stream, said cracking effluent stream and said gaseous pyrolysis product stream in a deethanizer column to provide a deethanizer overhead stream and a deethanized bottom stream.

10 . The process of claim 9 further comprising fractionating the deethanizer overhead stream in a demethanizer column and splitting a demethanized bottoms stream to recover ethylene in a C2 splitter column.

11 . The process of claim 9 further comprising fractionating the deethanized bottom stream in a depropanizer column and splitting a depropanizer overhead stream to recover propylene in a C3 splitter column.

12 . The process of claim 11 further comprising fractionating a depropanized bottoms stream in a debutanizer column and feeding a debutanized bottoms stream to a cracking unit with said cracking unit feed stream.

13 . The process of claim 1 further comprising cracking said cracking unit feed stream with a preexisting cracking unit feed stream.

14 . An apparatus for pyrolyzing plastics comprising: a pyrolysis reactor, a separator in downstream communication with said pyrolysis reactor, a recovery section in downstream communication with said separator and a cracking unit in downstream communication with said separator and said recovery section in downstream communication with said cracking unit.

15 . The apparatus of claim 14 further comprising a distillate stripper column in downstream communication with a bottoms line of said separator and said cracking unit in downstream communication with a bottoms line of said distillate stripper column.

16 . The apparatus of claim 15 further comprising said recovery section in downstream communication with on overhead line of said distillate stripper column.

17 . A process for converting plastics to monomers comprising:
heating a plastic feed stream to a temperature of about 600 to about 1100° C. to pyrolyze the plastic feed stream to a pyrolysis product stream including monomers; separating said pyrolysis product stream into a gaseous pyrolysis product stream and a liquid pyrolysis product stream; recovering monomers from said gaseous pyrolysis product stream; taking a cracking unit feed stream from said liquid pyrolysis product stream; feeding said cracking unit feed stream to a cracking unit to produce a cracking effluent stream; and recovering monomers from said cracking effluent stream and said vapor pyrolysis stream together.

18 . The process of claim 17 further comprising fractionating said liquid pyrolysis product stream to provide a fractionated overhead stream and a fractionated bottoms stream and taking said cracking unit feed stream from said fractionated bottoms stream.

19 . The process of claim 18 further comprising recovering monomers from said fractionated overhead stream with said gaseous pyrolysis product stream.

20 . The process of claim 19 further comprising recovering a debutanized bottoms stream from said fractionated overhead stream and feeding said debutanized bottoms stream to said cracking unit.

Assignees

• Uop Llc

Inventors

• Allegro Ii Michael S
• Bozzano Andrea
• Montalbano Joseph A

Classifications

• Y02W30/62

  Plastics recycling; Rubber recycling · CPC title

• Y02P20/143

  the feedstock being recycled material, e.g. plastics · CPC title

• C10K1/04

  by cooling to condense non-gaseous materials {(C10K1/001 takes precedence)} · CPC title

• C10K1/003

  of acid contaminants, e.g. acid gas removal · CPC title

• C10B53/07 Primary

  {of solid raw materials consisting} of synthetic polymeric materials, e.g. tyres (recovery or working-up of waste materials of organic macromolecular compounds or compositions based thereon by dry-heat treatment for obtaining partially depolymerised materials C08J11/10; production of liquid hydrocarbon mixtures from rubber or rubber waste C10G1/10) · CPC title