Efficient furnace operation with medium-purity oxygen

Patent metadata

Field	Value
Publication number	US-9541290-B2
Application number	US-201514679149-A
Country	US
Kind code	B2
Filing date	Apr 6, 2015
Priority date	Apr 24, 2014
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

Disclosed is a method of operating a furnace containing a charge to heat the charge, comprising wherein gaseous oxidant comprising 60 vol. % to 85 vol. % oxygen is passed through a heated regenerator and into the furnace, so that the oxidant is heated to emerge from an oxidant port at a temperature of 500° C. to 1400° C., and gaseous fuel is fed into said furnace through two or more fuel ports; and the heated oxidant and fuel are combusted in the furnace to produce gaseous hot products of said combustion which heat the charge; and then the flow of oxidant through the regenerator into the furnace is discontinued, and said combustion products are passed into said oxidant port and through and out of said cooled regenerator to heat said regenerator, wherein the temperature of the combustion products that pass out of said regenerator is at least 500° C.; under dimensional and operational conditions which attain functional and economic advantages.

First claim

What is claimed is:

1. A method of operating a furnace containing a charge to heat the charge, comprising:
(A) providing gaseous oxidant comprising 60 vol. % to 85 vol. % oxygen;
(B) passing the gaseous oxidant through a heated regenerator and out of an oxidant port into a furnace, to heat the oxidant in the regenerator so that it emerges from the oxidant port at a temperature of 500° C. to 1400° C., and to thereby cool said regenerator; and feeding gaseous fuel into said furnace through two or more fuel ports and combusting the fuel in the furnace with heated oxidant emerging from said oxidant port to produce gaseous hot products of said combustion which heat the charge;
(C) discontinuing the flow of oxidant through the regenerator into the furnace, and passing said combustion products into said oxidant port and through and out of said cooled regenerator to heat said regenerator, wherein the temperature of the combustion products that pass out of said regenerator is at least 500° C.; and
(D) alternating steps (B) and (C),

wherein said oxidant port and said fuel ports are located above the top surface of said charge in said furnace;
wherein at least one of said fuel ports is located on each side of a vertical line passing through the center of said oxidant port and said fuel ports are located 10 to 60 fuel port diameters from said oxidant port; and
wherein the fuel that is combusted with oxidant from a given oxidant port is fed into the furnace from two or more fuel ports at velocities of 40 to 350 m/sec, and the oxidant is fed into the furnace from the oxidant port at a velocity of 2 to 20 m/sec, wherein the fuel fed from said fuel ports entrains gaseous combustion products in said furnace before combusting with the high temperature oxidant stream.

2. The method according to claim 1 wherein the bottom of the oxidant port opening is 0.76 to 1.52 m (30 to 60 inches) above the charge in the furnace.

3. The method according to claim 1 wherein the oxidant velocity is between 2 and 20 m/sec.

4. The method according to claim 1 wherein gaseous oxidant from each oxidant port combusts with fuel that is fed from at least 2 fuel ports.

5. The method according to claim 4 wherein the fuel that is fed from the at least 2 fuel ports and that combusts with oxidant from an oxidant port is fed at different velocities.

6. The method according to claim 4 wherein a fuel port is oriented to direct the flame toward the center of the oxidant port centerline.

7. The method according to claim 1 wherein the fuel is fed from the fuel ports at velocities between 40 and 350 m/sec.

8. The method according to claim 1 wherein said gaseous fuel from the fuel port close to the furnace refractory wall is fed at a lower velocity to achieve reduced entrainment of the gaseous oxidant to lessen the energy release close to the walls of the furnace, while said gaseous fuel from the fuel ports removed from the furnace side walls is fed at higher velocities to enhance the entrainment of furnace flue gases before combusting with the oxidant stream.

9. The method according to claim 1 wherein one or more of the fuel ports are 0.7 m or more above the charge in the furnace.

10. The method according to claim 1 wherein the oxidant opening has an aspect ratio, A 1 (oxidant)/A 2 (fuel), of greater than or equal to 500.

11. The method according to claim 1 wherein gaseous oxidant fed from an oxidant port sweeps the furnace crown, preventing buildup of volatile alkali close to the furnace crown.

Assignees

• Iyoha Osemwengie Uyi
• Praxair Technology Inc

Inventors

• Iyoha Osemwengie Uyi

Classifications

• F23L7/007 Primary

  Supplying oxygen or oxygen-enriched air · CPC title

• F23L15/02

  Arrangements of regenerators · CPC title

• F27D2019/0043

  Amount of air or O2 to the burner · CPC title

• Y02P10/122

  by capturing or storing CO2 · CPC title

• C03B5/2353 Primary

  by combustion with pure oxygen or oxygen-enriched air, e.g. using oxy-fuel burners or oxygen lances · CPC title