Method and shaft furnace for burning carbon-containing material in a shaft furnace

Patent metadata

Field	Value
Publication number	US-11703280-B2
Application number	US-202017436715-A
Country	US
Kind code	B2
Filing date	Mar 4, 2020
Priority date	Mar 8, 2019
Publication date	Jul 18, 2023
Grant date	Jul 18, 2023

Abstract

A shaft furnace for firing carbonate-containing material may include, in a flow direction of the material, a preheating zone, a firing zone, a cooling zone, and a material outlet for discharging the material from the shaft furnace. Burner lances project into the firing zone. At least one burner lance has a first penetration depth into the firing zone and at least one further burner lance has a second penetration depth into the firing zone that is greater than the first penetration depth. A primary air conduit may be configured to convey combustion air and may be connected to at least one burner lance. An oxygen conduit for conveying oxygen into the firing zone may be arranged such that oxygen flows from the oxygen conduit at least one burner lance having the second penetration depth.

First claim

What is claimed is:

1. A shaft furnace for firing material that contains carbonate, the shaft furnace comprising:
in a flow direction of the material, a preheating zone, a firing zone, a cooling zone, and a material outlet for discharging the material;
burner lances that project into the firing zone, wherein a first of the burner lances has a first penetration depth into the firing zone and a second of the burner lances has a second penetration depth into the firing zone that is greater than the first penetration depth;
a first ring conduit that extends around a circumference of a shaft wall of the shaft furnace;
a second ring conduit that extends around the circumference of the shaft wall;
a first primary air conduit that conveys combustion air through the first primary air conduit, into the first ring conduit and into the first burner lance, and a second primary air conduit that conveys combustion air through the second primary air conduit, into the second ring conduit and into the second burner lance;
and

an oxygen conduit that conveys oxygen into the firing zone, wherein the oxygen conduit is disposed such that oxygen flows from the oxygen conduit to the second burner lance, wherein the oxygen conduit is connected exclusively to the second primary air conduit so that oxygen is configured to flow from the oxygen conduit, through the second ring conduit and into the second primary air conduit.

2. The shaft furnace of claim 1 wherein the oxygen conduit is connected to the second burner lance so that oxygen for combustion of fuel is configured to flow into the second burner lance.

3. The shaft furnace of claim 1 wherein the oxygen conduit is connected exclusively to burner lances that have the second penetration depth.

4. The shaft furnace of claim 1 wherein the oxygen conduit comprises means for regulating an amount of oxygen flowing through the oxygen conduit.

5. The shaft furnace of claim 1 wherein the second ring conduit is positioned at a distinct and offset location around the shaft wall relative to the first ring conduit.

6. A shaft furnace for firing material containing carbonate, the shaft furnace comprising:
in a flow direction of the material, a preheating zone, a firing zone, a cooling zone, and a material outlet for discharging the material;
burner lances that project into the firing zone, wherein a first of the burner lances has a first penetration depth into the firing zone and a second of the burner lances has a second penetration depth into the firing zone that is greater than the first penetration depth;
a first ring conduit that extends around a circumference of a shaft wall of the shaft furnace;
a second ring conduit that extends around the circumference of the shaft wall;
a first primary air conduit that conveys primary combustion air through the first primary air conduit, into the first ring conduit and into the first burner lance; and a second primary air conduit that conveys primary combustion air through the second primary air conduit, into the second ring conduit and into the second burner lance, wherein the second primary air conduit extends at least partly through a preheating device that heats the primary combustion air in the second primary air conduit, wherein the primary combustion air conveyed by the first primary air conduit is not preheated by the preheating device.

7. The shaft furnace of claim 6 comprising an oxygen conduit for conveying oxygen into the firing zone, wherein the oxygen conduit is configured to carry oxygen to the second burner lance and a third of the burner lances that has a third penetration depth into the firing zone that is greater than the first penetration depth but less than the second penetration depth.

8. The shaft furnace of claim 7 wherein the oxygen conduit comprises means for regulating an amount of oxygen flowing through the oxygen conduit, wherein the means for regulating is configured such that the amount of oxygen configured to flow to the second burner lance is greater than an amount of oxygen configured to flow to the third burner lance.

9. The shaft furnace of claim 6 wherein the second primary air conduit is connected exclusively to the second burner lance so that preheated primary combustion air is configured to be fed exclusively to the second burner lance.

10. The shaft furnace of claim 6 comprising the preheating device, wherein the preheating device comprises a preheating zone within the shaft furnace, wherein the second primary air conduit runs at least partly through the preheating zone.

11. The shaft furnace of claim 10 wherein the second primary air conduit comprises immersion conduits that extend at least partly or completely through the preheating zone.

12. The shaft furnace of claim 6 wherein at least one of:
the first penetration depth is equal to or less than one third of a radius of the firing zone; or
the second penetration depth is about one third of the radius of the firing zone.

13. The shaft furnace of claim 6 wherein the second ring conduit is positioned at a distinct and offset location around the shaft wall relative to the first ring conduit.

14. A process for firing material that contains carbonate in a shaft furnace, the process comprising:
causing the material to flow through a preheating zone, a firing zone, and a cooling zone to a material outlet;
introducing fuel in the firing zone or adjacent thereto via burner lances, wherein a first of the burner lances has a first penetration depth and a second of the burner lances has a second penetration depth that is greater than the first penetration depth;
conveying primary combustion air through a first ring conduit that extends around a circumference of a shaft wall of the shaft furnace to the first of the burner lances; and
conveying oxygen along with the primary combustion air through a second ring conduit that extends around the circumference of the shaft wall to only the second of the burner lances that have the second penetration depth or conveying oxygen into a primary air conduit and through a second ring conduit that extends around the circumference of the shaft wall that conveys the primary combustion air only to the second of the burner lances that have the second penetration depth.

15. The process of claim 14 comprising enriching the primary combustion air with oxygen to have an oxygen content of 40% to 90%.

16. A process for firing material that contains carbonate in a shaft furnace, the process comprising:
causing the material to flow through a preheating zone, a firing zone, and a cooling zone;
directing fuel through (i) a first primary air conduit that conveys the fuel through a first ring conduit that extends around a circumference of a shaft wall of the shaft furnace; and (ii) a second primary air conduit that conveys the fuel through a second ring conduit that extends around the circumference of the shaft wall;
introducing fuel in the firing zone or adjacent thereto via burner lances, wherein a first of the burner lances, receives fuel from the first ring conduit and has a first penetration depth and a second of the burner lances, receives fuel from the second ring conduit and has a second penetration depth that is greater than the first penetration depth; and
conveying primary combustion air that has been preheated exclusively to burner lances that have the second penetration depth.

17. The process of claim 16 comprising preheating the primary combustion air to a temperature of 250° C. to 500° C.

Assignees

• Maerz Ofenbau
• Thyssenkrupp Ag

Inventors

• Piringer Hannes
• Bucher Patrick

Classifications

• F27D7/02 Primary

  Supplying steam, vapour, gases or liquids · CPC title

• C04B2/12

  in shaft or vertical furnaces (shaft or vertical furnaces in general F27B1/00) · CPC title

• F23L7/007

  Supplying oxygen or oxygen-enriched air · CPC title

• F23N3/00

  Regulating air supply or draught (conjointly with fuel supply F23N1/00) · CPC title

• F27B1/10 Primary

  Details, accessories or equipment specially adapted for furnaces of these types · CPC title