Fibres

Patent metadata

Field	Value
Publication number	US-2023295396-A1
Application number	US-202118010995-A
Country	US
Kind code	A1
Filing date	Jun 15, 2021
Priority date	Jun 17, 2020
Publication date	Sep 21, 2023
Grant date	—

Abstract

A process (1, 2) for processing feedstock containing cotton fibres and PET fibres, the process (1, 2) comprises: i. heating a suspension of feedstock containing cotton fibres and PET fibres in water at a temperature above 180° C. to produce a mixture comprising char; ii. removing the water from the mixture comprising char; iii. adding a base to the mixture comprising char to produce a terephthalate salt in a liquid phase; iv. removing the char from the liquid phase to produce dried char; v. acidifying the liquid phase to produce terephthalic acid.

First claim

1 . A process for processing feedstock containing cotton fibres and PET fibres, the process comprising:
i. heating a suspension of feedstock containing cotton fibres and PET fibres in water at a temperature above 180° C. to produce a mixture comprising char; ii. removing the water from the mixture comprising char; iii. adding a base to the mixture comprising char to produce a terephthalate salt in a liquid phase; iv. removing the char from the liquid phase to produce dried char; v. acidifying the liquid phase to produce terephthalic acid.

2 . A process according to claim 1 , further comprising shredding the feedstock prior to Step i.

3 . A process according to claim 1 , wherein the ratio of water to feedstock is between 4:1 to 8:1 (w/w).

4 . A process according to claim 1 , wherein Step i. comprises heating a suspension of feedstock containing cotton fibres and PET fibres in water at a temperature of between 180 to 240° C.

5 . A process according to claim 1 , wherein Step i. further comprises heating a suspension of feedstock containing cotton fibres and PET fibres in water under a pressure of greater than 2.0×10 6 Pa (20 bar).

6 . A process according to claim 2 , wherein Step ii. Comprises removing the water from the mixture comprising char via filtration.

7 . A process according to claim 1 , further comprising recovering ethylene glycol from the water removed in Step ii. of the process.

8 . A process according to claim 1 , wherein Step iii. comprises adding a base comprising ammonia and/or ammonium hydroxide to the mixture comprising char to produce diammonium terephthalate in a liquid phase.

9 . A process according to claim 8 , wherein Step iii. is performed at a temperature, e.g. between 0 to 40° C.

10 . A process according to claim 1 , wherein Step iv. comprises filtering the char from the liquid phase and further comprises drying the filtered char to produce a solid fuel.

11 . (canceled)

12 . A process according to claim 1 , further comprising forming pellets and/or briquettes from the char to form a solid fuel.

13 . A process according to claim 1 , further comprising Step vi. purifying the liquid phase by contacting the liquid phase with one or more of activated carbon or clay.

14 . A process according to claim 12 , wherein Step vi. is performed after Step iii. and before Step v.

15 . A process according to claim 12 , comprising subsequently removing the activated carbon and/or clay by filtration.

16 . (canceled)

17 . A process according to claim 1 , wherein the pure terephthalic acid is collected via filtration.

18 . A process according to claim 1 , further comprising Step vii. torrefaction of the mixture comprising char.

19 . A process according to claim 18 , wherein Step vii. is performed after Step ii. and before Step iii. of the process.

20 . A process according to claim 18 , wherein Step vii. is performed at a temperature between 200 to 280° C.

21 . A process according to claim 18 , wherein Step vii. is performed for less than one hour.

22 . Terephthalic acid produced from the process of claim 1 .

Assignees

• Coal Products Ltd
• Univ Nottingham

Inventors

• Gill Andrew
• Snape Colin

Classifications

• C08J11/14 Primary

  by treatment with steam or water · CPC title

• C08J11/04 Primary

  of polymers · CPC title

• C08J2367/02

  Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence) · CPC title

• C07C51/02

  from salts of carboxylic acids · CPC title

• Y02W30/62

  Plastics recycling; Rubber recycling · CPC title