Method and installation for the indirect reduction of particulate oxide-containing ores

• US 20030159541A1
• Filed: 03/04/2003
• Published: 08/28/2003
• Est. Priority Date: 06/28/2000
• Status: Active Grant

• Current Assignee: Pohang Iron & Steel Company Limited (Posco), Primetals Technologies Austria Gmbh, Research Institute of Industrial Science and Technology
• Original Assignee: Pohang Iron & Steel Company Limited (Posco), Research Institute of Industrial Science and Technology, Voest-Alpine Industrieanlagenbau GmbH (Voestalpine AG)
• Inventors: Joo, Sanghoon, Kepplinger, Leopold Werner, Hauzenberger, Franz, Schenk, Johannes
• Granted Patent: US 6,960,238 B2
• Time in Patent Office: Days
• US Class Current: 75/450
• CPC Class Codes: B28B 11/245 Curing concrete articles B28B11/242 takes precedence
• CPC Class Codes: B28B 13/04 Discharging the shaped articles discharging tubular articles after shaping B28B21/90; conveying systems for ceramic mouldings B65G49/08
• CPC Class Codes: C21B 13/002 Reduction of iron ores by passing through a heated column of carbon
• CPC Class Codes: C21B 13/0033 In fluidised bed furnaces or apparatus containing a dispersion of the material
• CPC Class Codes: C21B 13/14 Multi-stage processes processes carried out in different vessels or furnaces
• CPC Class Codes: C21B 2100/22 by reforming
• CPC Class Codes: C21B 2100/44 Removing particles, e.g. by scrubbing, dedusting
• CPC Class Codes: C21B 2100/66 Heat exchange
• CPC Class Codes: C22B 5/14 fluidised material
• CPC Class Codes: F27B 15/00 Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion apparatus in general for carrying out chemical or physical processes in a fluidised bed reactor B01J8/24 - B01J8/44
• CPC Class Codes: Y02P 10/122 by capturing or storing CO2
• CPC Class Codes: Y02P 10/134 by avoiding CO2, e.g. using hydrogen
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

In a process for the gas reduction of particulate oxide-containing ores, in particular iron-oxide-containing material, in the fluidized-bed process at a pressure of <5 bars, wherein the ore by aid of a reducing gas produced from coal is heated, optionally also pre-reduced, in a fluidized-bed reactor (1) designed as a pre-heating stage (5), subsequently is reduced to sponge iron in at least one fluidized-bed reactor (2, 3) designed as a reduction stage (7, 8), the reducing gas via a reducing-gas feed duct (12) or reducing-gas duct (13) being conducted from the reduction stage (7, 8) to the pre-heating stage (5) in the opposite direction of the material to be reduced and conducted from stage to stage, and being drawn off as an export gas after purification, heat is supplied to the reducing gas fed to the reduction stage (7, 8) and/or pre-heating stage (5), namely by combustion, together with oxygen and/or air, of a portion of the reducing gas provided for the gas reduction in the reduction stage (7, 8) and/or the pre-heating stage (5). (FIG. 1)

Claims

1. A process for the gas reduction of particulate oxide-containing ores, in particular iron-oxide-containing material, in the fluidized-bed process at a pressure of <

5 bars, wherein the ore by aid of a reducing gas produced from coal is heated, optionally also pre-reduced, in a fluidized-bed reactor (1) designed as a pre-heating stage (5), subsequently is reduced to sponge iron in at least one fluidized-bed reactor (2, 3) designed as a reduction stage (7, 8), the reducing gas via a reducing-gas feed duct (12) or reducing-gas duct (13) being conducted from the reduction stage (7, 8) to the pre-heating stage (5) in the opposite direction of the material to be reduced and conducted from stage to stage, and being drawn off as an export gas after purification, characterized in that heat is supplied to the reducing gas fed to the reduction stage (7, 8) and/or pre-heating stage (5), namely by combustion, together with oxygen and/or air, of a portion of the reducing gas provided for the gas reduction in the reduction stage (7, 8) and/or the pre-heating stage (5). (FIG.

     1)

4. A process according to anyone of claims 1 to 3, characterized in that the portion to be burnt of the reducing gas, export gas or cooling gas is subjected to a scrubbing operation before being burnt.

6. A process according to anyone of claims 1 to 5, characterized in that the combustion is done in a burner (25) provided in the reducing-gas feed duct (12) or reducing-gas duct (13). (FIGS. 1, 2, 3, 9)

7. A process according to anyone of claims 1 to 6, characterized in that the combustion is done in a combustion chamber separated from the reducing-gas feed duct (12) or reducing-gas duct (13), the combustion gases and possibly not burnt solids subsequently being introduced into the reducing-gas feed duct (12) or reducing-gas duct (13). (FIGS. 4, 5)

8. A process according to anyone of claims 1 to 7, characterized in that the combustion is done by means of at least one burner (38) associated with the fluidized-bed reactor (30), the combustion gases being introduced directly into the fluidized-bed reactor (30). (FIGS. 6 to 8)

9. A process according to claim 1, characterized in that oxygen and/or air are fed into the reducing-gas feed duct (12) or reducing-gas duct (13) via lances.

10. A process according to claim 1, characterized in that oxygen and/or air are fed into the fluidized-bed reactor (30) via a burner (38), preferably a lance.

11. A process according to anyone of claims 1 to 10, characterized in that reducing gas and/or export gas and/or cooling gas and/or external combustible gas and/or solid and/or liquid and/or gaseous fuel on a hydrocarbon basis are further used for the combustion, in addition to the gas respectively used.

12. A process according to anyone of claims 1 to 11, characterized in that a material increasing the proportion of reductants in the reducing gas by at least partially reacting with the reducing gas, in particular natural gas and/or coal, is admixed to the reducing gas fed to the reduction stage (7, 8) and/or pre-heating stage (5).

14. A plant for carrying out the process according to anyone of claims 1 to 13, comprising at least two fluidized-bed reactors subsequently connected in series for the gas reduction of particulate oxide-containing ores by means of a CO and H₂-containing reducing gas produced from coal, comprising a reducing-gas feed duct (12) leading to the fluidized-bed reactor (3) arranged last when seen in the direction of flow of the oxide-containing material, a discharge duct (14) departing from the fluidized-bed reactor (1) arranged first when seen in the direction of flow of the oxide-containing material and discharging spent reducing gas as export gas, a gas recycle duct (22) for cooling gas, branching off the reducing-gas feed duct (12) and running back into the reducing-gas feed duct (12) via a scrubber (23), and comprising a reducing-gas duct (13) provided for conducting the reducing gas from one fluidized-bed reactor (3) into the preceding fluidized-bed reactor (1, 2), characterized in that the plant is flow-connected with at least one burner (25, 38) having a feed duct (12, 13, 26, 28, 39) for reducing gas and/or export gas and/or cooling gas and/or external combustible gas and/or solid and/or liquid fuel and/or oxygen and/or air for the combustion of a portion of the reducing gas, export gas or cooling gas, of external combustible gas or solid or liquid fuel together with oxygen and/or air.

15. A plant according to claim 14, characterized in that a scrubber (15) is provided in the export-gas discharge duct (14) and scrubbed export gas is feedable to the burner (25) via an export-gas duct (26). (FIGS. 2, 4)

16. A plant according to claim 14 or 15, characterized in that the burner (25) with its combustion chamber (25a) is provided directly in the reducing-gas feed duct (12) or the reducing-gas duct (13). (FIGS. 1 to 3, 9)

17. A plant according to anyone of claims 14 to 16, characterized in that the burner (25, 38) is designed as an oxygen and/or air lance.

2. A process for the gas reduction of particulate oxide-containing ores, in particular iron-oxide-containing material, in the fluidized-bed process at a pressure of <

5 bars, wherein the ore by aid of a reducing gas produced from coal is heated, optionally also pre-reduced, in a fluidized-bed reactor (1) designed as a pre-heating stage (5), subsequently is reduced to sponge iron in at least one fluidized-bed reactor (2, 3) designed as a reduction stage (7, 8), the reducing gas via a reducing-gas feed duct (12) or reducing-gas duct (13) being conducted from the reduction stage (7, 8) to the pre-heating stage (5) in the opposite direction of the material to be reduced and conducted from stage to stage, and being drawn off as an export gas after purification, characterized in that heat is supplied to the reducing gas fed to the reduction stage (7, 8) and/or pre-heating stage (5), namely by combustion, together with oxygen and/or air, of a portion of the export gas. (FIGS. 2,

     4)

3. A process for the gas reduction of particulate oxide-containing ores, in particular iron-oxide-containing material, in the fluidized-bed process at a pressure of <

5 bars, wherein the ore by aid of a reducing gas produced from coal is heated, optionally also pre-reduced, in a fluidized-bed reactor (1) designed as a pre-heating stage (5), subsequently is reduced to sponge iron in at least one fluidized-bed reactor (2, 3) designed as a reduction stage (7, 8), the reducing gas via a reducing-gas feed duct (12) or reducing-gas duct (13) being conducted from the reduction stage (7, 8) to the pre-heating stage (5) in the opposite direction of the material to be reduced and conducted from stage to stage, and being drawn off as an export gas after purification, characterized in that heat is supplied to the reducing gas fed to the reduction stage (7, 8) and/or pre-heating stage (5), namely by combustion, together with oxygen and/or air, of a portion of the cooling gas used for cooling the reducing gas to be introduced into the final reduction zone (8). (FIGS. 3,

     5)

5. A process for the gas reduction of particulate oxide-containing ores, in particular iron-oxide-containing material, in the fluidized-bed process at a pressure of <

5 bars, wherein the ore by aid of a reducing gas produced from coal is heated, optionally also pre-reduced, in a fluidized-bed reactor (1) designed as a pre-heating stage (5), subsequently is reduced to sponge iron in at least one fluidized-bed reactor (2, 3) designed as a reduction stage (7, 8), the reducing gas via a reducing-gas feed duct (12) or reducing-gas duct (13) being conducted from the reduction stage (7, 8) to the pre-heating stage (5) in the opposite direction of the material to be reduced and conducted from stage to stage, and being drawn off as an export gas after purification, characterized in that heat is supplied to the reducing gas fed to the reduction stage (7, 8) and/or pre-heating stage (5), namely by combustion, together with oxygen and/or air, of external combustible gas and/or solid and/or liquid fuel. (FIG.

     9)

13. A process for the gas reduction of particulate oxide-containing ores, in particular iron-oxide-containing material, in the fluidized-bed process at a pressure of <

5 bars, wherein the ore by aid of a reducing gas produced from coal is heated, optionally also pre-reduced, in a fluidized-bed reactor (1) designed as a pre-heating stage (5), subsequently is reduced to sponge iron in at least one fluidized-bed reactor (2, 3) designed as a reduction stage (7, 8), the reducing gas via a reducing-gas feed duct (12) or reducing-gas duct (13) being conducted from the reduction stage (7, 8) to the pre-heating stage (5) in the opposite direction of the material to be reduced and conducted from stage to stage, and being drawn off as an export gas after purification, characterized in that a material increasing the proportion of reductants in the reducing gas by at least partially reacting with the reducing gas, in particular natural gas and/or coal, is admixed to the reducing gas fed to the reduction stage (7, 8) and/or pre-heating stage (5).

18. A plant according to anyone of claims 13 to 16, characterized in that the burner (25) has a combustion chamber (25a) separated from the reducing-gas feed duct (12) or reducing-gas duct (13), which is flow-connected with the reducing-gas feed duct (12) or reducing-gas duct (13). (FIGS. 4, 5)

19. A plant according to anyone of claims 13 to 17, characterized in that the burner (38) is arranged in a fluidized-bed reactor (30), namely either below the fluidized bed (35), on the level of the fluidized bed (35) or above the fluidized bed (35). (FIGS. 6 to 8)