Furnace

Patent metadata

Field	Value
Publication number	US-10551059-B2
Application number	US-201515534556-A
Country	US
Kind code	B2
Filing date	Dec 17, 2015
Priority date	Dec 17, 2014
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

A furnace, and a method of firing it, wherein part of the fuel supplied to the furnace is produced from waste plastics by a depolymerisation process, waste heat from the furnace being used to promote the depolymerisation process. The furnace is equipped with regenerators for waste heat recovery and is fired alternately in first and second opposed directions, with the direction of firing periodically reversing between the first direction and the second direction. The supply of fuel to the furnace is temporarily interrupted while the direction of firing is reversing, means being provided to accommodate the fuel produced during the temporary interruption. The furnace may be used for producing glass.

First claim

The invention claimed is:

1. A method of firing a furnace by burning fuel, comprising:
providing a supply of fuel to the furnace, wherein part of the fuel supplied to the furnace and burnt in the furnace is produced from waste plastics by a depolymerisation process, waste heat from the furnace being used to promote the depolymerisation process,
wherein the waste plastics is fed as a loose material,
wherein the depolymerisation process is carried out under an inert atmosphere,
wherein the furnace is equipped with regenerators for waste heat recovery,
firing the furnace alternately in first and second opposed directions, with the direction of firing periodically reversing between the first direction and the second direction,
temporarily interrupting the supply of fuel to the furnace while the direction of firing is reversing, means being provided to accommodate the fuel produced during the temporary interruption.

2. The method as claimed in claim 1 , wherein substantially all the heat needed to promote the depolymerisation process is supplied from the furnace.

3. The method as claimed in claim 1 , wherein the fuel produced from waste plastics contains at least 70% hydrocarbons.

4. The method as claimed in claim 1 , wherein the fuel produced from waste plastics contains at least 80% hydrocarbons.

5. The method as claimed in claim 1 , wherein the fuel produced from waste plastics contains at least 90% hydrocarbons.

6. The method as claimed in claim 1 , wherein the fuel produced from waste plastics has a lower heating value (LHV) from 10 to 100 MJ/Nm3.

7. The method as claimed in claim 1 , wherein the fuel produced from waste plastics has a lower heating value (LHV) from 20 to 80 MJ/Nm3.

8. The method as claimed in claim 1 , wherein the fuel produced from waste plastics has a lower heating value (LHV) from 25 to 70 MJ/Nm3.

9. The method as claimed in claim 1 , wherein the fuel produced from waste plastics has a lower heating value (LHV) from 30 to 50 MJ/Nm3.

10. The method as claimed in claim 1 , wherein the fuel is produced from waste plastics by depolymerisation at 350° C. to 650° C.

11. The method as claimed in claim 1 , wherein the fuel is produced from waste plastics by depolymerisation at 400° C. to 450° C.

12. The method as claimed in claim 1 , wherein the fuel produced by the depolymerisation process is stored before being supplied to the furnace.

13. The method as claimed in claim 1 , wherein the fuel produced by the depolymerisation process is supplied directly to the furnace, i.e. without storing the fuel.

14. The method as claimed in claim 1 , wherein burning fuel in the furnace produces exhaust gases containing waste heat which is used to promote the depolymerisation process, and the depolymerisation process takes place in a reactor, which comprises means of exchanging waste heat between the exhaust gases of the furnace and the waste plastics.

15. The method as claimed in claim 14 , wherein the exhaust gases are supplied directly to the reactor.

16. The method as claimed in claim 14 , wherein waste heat is supplied to the reactor via a secondary circuit, the exhaust gases being supplied to a heat exchanger in the secondary circuit, the heat exchanger abstracting heat from the exhaust gases and supplying the heat to the reactor via the secondary circuit.

17. The method as claimed in claim 1 , wherein the waste plastics are compressed prior to the depolymerisation process.

18. A furnace which is fired by burning fuel and a plant for producing fuel from waste plastics by a depolymerisation process, wherein the plant comprises an inert gas purge system, a heated drying and dechlorination vessel containing molten plastic, a heated cracking reactor and a conduit by means of which molten plastic leaves the drying and dechlorination vessel and enters the cracking reactor, and the plant supplies fuel to the furnace, and waste heat from the furnace is used to promote the depolymerisation process, the furnace being equipped with regenerators for waste heat recovery, wherein the furnace is fired alternately in first and second opposed directions, with the direction of firing periodically reversing between the first direction and the second directions, means being provided to accommodate the fuel produced during the reversing of the direction of firing.

19. The furnace as claimed in claim 18 , comprising a means of supplying waste heat from the furnace to the cracking reactor.

20. The furnace as claimed in claim 19 , comprising a means of supplying fuel produced in the cracking reactor from the cracking reactor to the furnace.

21. The method as claimed in claim 1 , wherein the carbon to hydrogen ratio of the fuel ranges from 65% to 95% by weight.

Assignees

• Pilkington Group Ltd

Inventors

• Inskip Julian

Classifications

• C03B5/237

  Regenerators or recuperators specially adapted for glass-melting furnaces · CPC title

• C03B5/235

  Heating the glass (C03B5/02, C03B5/18, C03B5/225 take precedence) · CPC title

• Y02P20/143

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

• Y02P20/129

  Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines · CPC title

• F27D99/0033

  using burners · CPC title