Enhanced waste heat recovery using a pre-reformer combined with oxygen and fuel pre-heating for combustion

Patent metadata

Field	Value
Publication number	US-10584052-B2
Application number	US-201715417972-A
Country	US
Kind code	B2
Filing date	Jan 27, 2017
Priority date	Jan 27, 2017
Publication date	Mar 10, 2020
Grant date	Mar 10, 2020

Abstract

Disclosed are methods for operating a glass furnace, the method comprises the steps of feeding a non-pre-reformed hydrocarbon fuel gas stream to a pre-reformer forming a pre-reformed hydrocarbon fuel gas stream, feeding the pre-reformed hydrocarbon fuel gas stream to burners of the furnace, combusting oxidant and the pre-reformed hydrocarbon fuel gas with the burners to produce flue gas, heating air through heat exchange with the flue gas at a recuperator, and transferring heat from heated air to pre-reformer tubes of the pre-reformer. A glass furnace system is also disclosed.

First claim

We claim:

1. A method for operating a glass furnace, the method comprising the steps of:
feeding a non-pre-reformed hydrocarbon fuel gas stream to a pre-reformer forming a pre-reformed hydrocarbon fuel gas stream, wherein the pre-reformer is a low pressure pre-reformer having a pressure ranging from 1 to 5 bars;
feeding the pre-reformed hydrocarbon fuel gas stream to burners of the furnace;
combusting oxidant and the pre-reformed hydrocarbon fuel gas with the burners to produce flue gas;
heating air through heat exchange with the flue gas at a recuperator; and
transferring heat from heated air to pre-reformer tubes of the pre-reformer.

2. The method as claimed in claim 1 , further comprising the step of
feeding an additional hydrocarbon fuel gas stream to the glass furnace; and
combusting the additional hydrocarbon fuel gas and the pre-reformed hydrocarbon fuel gas in the presence of the oxidant in the glass furnace and produce the flue gas therefrom.

3. The method as claimed in claim 2 , wherein the percentage of the hydrocarbon fuel gas stream is x % of the sum of the hydrocarbon fuel gas stream and the additional pre-heated hydrocarbon fuel gas stream, where 0<x≤100.

4. The method as claimed in claim 2 , wherein the hydrocarbon fuel gas and the additional hydrocarbon fuel gas are natural gas.

5. The method as claimed in claim 2 , further comprising the steps of
desulfurizing the hydrocarbon fuel gas stream before pre-reforming; and
optionally desulfurizing the additional hydrocarbon fuel gas before feeding to the glass furnace.

6. The method as claimed in claim 5 , further comprising the step of
pre-heating the pre-reformed hydrocarbon fuel gas stream before feeding to the glass furnace; and
pre-heating the additional hydrocarbon fuel gas before feeding to the glass furnace.

7. The method as claimed in claim 6 , wherein the temperature of the pre-reformed hydrocarbon fuel gas is higher than that of the additional pre-heated hydrocarbon if the additional hydrocarbon fuel gas is pre-heated in a separate heat exchanger.

8. The method as claimed in claim 7 , wherein the temperature of the additional pre-heated hydrocarbon fuel gas is below the coking temperature of the higher hydrocarbons contained in the non-pre-reformed hydrocarbon fuel gas.

9. The method as claimed in claim 1 , further comprising the step of pre-heating the oxidant before feeding it to the burners.

10. The method as claimed in claim 9 , wherein the oxidant is oxygen or oxygen-enriched air.

11. The method as claimed in claim 1 , further comprising the step of drying the pre-reformed hydrocarbon fuel gas before feeding it to the burners.

12. The method as claimed in claim 1 , wherein the pre-reformer is a non-adiabatic pre-reformer.

13. The method as claimed in claim 1 , wherein the pre-reformer is a low pressure pre-reformer having a pressure ranging from 1 to 5 bars.

14. The method as claimed in claim 12 , wherein the non-adiabatic pre-reformer is a quasi-isothermal pre-reformer comprising a multiple stages of adiabatic pre-formers or a multiple tube reactors where pre-reformed reactants are re-heated using the heated air between the stages or reactors, thereby maintaining the temperature of the non-adiabatic pre-reformer unchanged or fluctuated in a preferred temperature range.

15. A glass furnace system, the system comprising:
a pre-reformer adapted and configured to receive a heated air stream and a feedstock of a hydrocarbon fuel gas stream in the presence of steam under conditions effective for pre-reforming higher hydrocarbons in the hydrocarbon fuel gas to methane, CO and H 2 to produce a pre-reformed hydrocarbon fuel gas stream, wherein the pre-reformer is a non-adiabatic pre-reformer;
a glass furnace including burners adapted and configured to combust oxidant and the pre-reformed hydrocarbon fuel gas to produce flue gas; and
a recuperator adapted and configured to perform heat exchange between the flue gas and an air stream that has a temperature lower than that of a hot air stream, so as to produce the hot air stream received by the pre-reformer.

16. The system as claimed in claim 15 , further comprising a hydrodesulfurization system adapted and configured to desulfurize the hydrocarbon fuel gas;
a dryer adapted and configured to remove water from the pre-reformed hydrocarbon fuel gas;
a first heat exchanger adapted and configured to pre-heat the pre-reformed hydrocarbon fuel gas; and
a second heat exchanger adapted and configured to pre-heat the oxidant.

17. The system as claimed in claim 16 , further comprising an additional feedstock of the hydrocarbon fuel gas fed to the glass furnace for use as fuel.

18. The system as claimed in claim 17 , further comprising
a second hydrodesulfurization system adapted and configured to desulfurize the additional feedstock of the hydrocarbon fuel gas; and
optionally a third heat exchanger adapted and configured to pre-heat the desulfurized additional feedstock of the hydrocarbon fuel gas.

19. The system as claimed in claim 18 , wherein the additional feedstock of the hydrocarbon fuel gas is pre-heated by the first heat exchanger.

20. The system as claimed in claim 19 , wherein the amount of the feedstock of the hydrocarbon fuel gas is x % of the sum of the feedstock of the hydrocarbon fuel gas and the additional feedstock of the hydrocarbon fuel gas, wherein 0<x≤100.

21. The system as claimed in claim 20 , wherein the feedstock of the hydrocarbon fuel gas and the additional feedstock of the hydrocarbon fuel gas are natural gas.

Assignees

• Air Liquide American

Inventors

• Kang Taekyu
• Gagliano Robert A
• Pranda Pavol
• Iranshahi Ashkan

Classifications

• F23K2400/10

  Pretreatment · CPC title

• F23L7/007

  Supplying oxygen or oxygen-enriched air · CPC title

• F23K2900/01041

  Heating by using exhaust gas heat · CPC title

• F23K5/007 Primary

  Details · CPC title

• C03B5/237 Primary

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