High-temperature pyrolysis of plastics to monomers with high carbon to gas ratio

Patent metadata

Field	Value
Publication number	US-2022010212-A1
Application number	US-202117365571-A
Country	US
Kind code	A1
Filing date	Jul 1, 2021
Priority date	Jul 11, 2020
Publication date	Jan 13, 2022
Grant date	—

Abstract

A high-temperature plastic pyrolysis process that can produce high yields of ethylene, propylene and other light olefins from waste plastics is disclosed. The plastic feed is pyrolyzed at a high temperature of about 600 to about 900° C. directly to monomers, such as ethylene and propylene. During pyrolysis, the plastic feed is contacted with a diluent gas stream at a mole ratio of carbon feed to diluent gas of 0.6 to 20.

First claim

1 . A process for converting plastics to monomers comprising:
heating a plastic feed stream to an elevated temperature of about 600 to about 1100° C.; contacting the plastic feed stream with a diluent gas stream at a carbon feed to diluent gas mole ratio of 0.6 to 20; pyrolyzing the plastic to gaseous products including monomers; and recovering said monomers from said gaseous products.

2 . The process of claim 1 further comprising contacting the plastic feed stream with a stream of hot heat carrier particles to heat the plastic feed stream.

3 . The process of claim 2 further comprising lifting the stream of hot heat carrier particles with the diluent gas stream.

4 . The process of claim 3 further comprising lifting the stream of hot heat carrier particles into contact with the plastic feed stream.

5 . The process of claim 2 further comprising separating the heat carrier particles from the gaseous products.

6 . The process of claim 5 wherein the contacting step takes place in a reactor and further comprising reheating the separated heat carrier particles in a reheater and recycling the stream of hot heat carrier particles from the reheater to the reactor.

7 . The process of claim 5 further comprising combusting fuel gas in the reheater to reheat the stream of hot heat carrier particles.

8 . The process of claim 1 further comprising quenching the gaseous products with a cooling liquid to terminate the pyrolysis reaction.

9 . The process of claim 8 further comprising quenching the gaseous products with water and separating a quenched product into a product gas stream, a product liquid stream and an aqueous stream.

10 . The process of claim 9 further comprising compressing said product gas stream and washing the product gas stream with caustic to absorb acid gases.

11 . The process of claim 1 wherein the contacting step is performed in a reactor that has a refractory lining.

12 . The process of claim 1 wherein the plastic feed stream is in particulate form.

13 . The process of claim 11 further comprising preheating the plastic feed stream to above its melting point.

14 . A process for converting plastics to monomers comprising:
contacting a plastic feed stream with a stream of hot heat carrier particles at an elevated temperature to heat the plastic feed stream to a temperature of about 600 to about 1100° C. in the presence of a diluent gas stream at a carbon feed to diluent gas mole ratio of 0.6 to 20; pyrolyzing the plastic to gaseous products including monomers; and recovering said monomers from said gaseous products.

15 . The process of claim 14 further comprising lifting the stream of hot heat carrier particles with the diluent gas stream.

16 . The process of claim 2 further comprising separating the heat carrier particles from the gaseous products.

17 . The process of claim 5 wherein the contacting step takes please in a reactor and further comprising reheating the separated heat carrier particles in a reheater and recycling the stream of hot heat carrier particles from the reheater to the reactor.

18 . A process for converting plastics to monomers comprising:
contacting a plastic feed stream with a stream of hot heat carrier particles in a reactor at an elevated temperature to heat the plastic feed stream to a temperature of about 600 to about 1100° C. in the presence of a diluent gas stream at a carbon feed to diluent gas mole ratio of 0.6 to 20; pyrolyzing the plastic to gaseous products including monomers; and separating the heat carrier particles from the gaseous products; recovering said monomers from the gaseous products; reheating the separated heat carrier particles in a reheater; and recycling the stream of hot heat carrier particles from the reheater to the reactor.

19 . The process of claim 18 further comprising lifting the stream of hot heat carrier particles with the diluent gas stream.

20 . The process of claim 18 further comprising combusting fuel gas in the reheater to reheat the stream of hot heat carrier particles.

Assignees

• Uop Llc

Inventors

• Shi Yili
• Barger Paul T
• Abrevaya Hayim

Classifications

• Y02W30/62

  Plastics recycling; Rubber recycling · CPC title

• Y02P20/143

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

• C10G1/10

  from rubber or rubber waste · CPC title

• C10G2300/1003

  Waste materials · CPC title