# US 2018/0023152 A1 · Method for operating blast furnace

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- Number: US 2018/0023152 A1
- Document ID: US20180023152A1
- Status: Published application
- Kind: A1
- Application number: 15/547,891
- Filed: 2016-02-22
- Published: 2018-01-25
- Earliest claimed: 2015-03-02
- Assignees: Jfe Steel Corporation
- Applicants: Jfe Steel Corporation
- Inventors: Akinori MURAO; Naoki YAMAMOTO; Tomoyuki KAWASHIMA; Nobuyuki OOYAMA
- Web page: https://patentgrep.com/patent/US20180023152A1

## CPC

- C21B 5/003: {Injection of pulverulent coal}
- C21B 5/00: Making pig-iron in the blast furnace
- C21B 5/001: {Injecting additional fuel or reducing agents}
- C21B 7/00: Blast furnaces
- C21B 7/16: Tuyéres
- C21B 7/163: {Blowpipe assembly}
- F27B 1/16: Arrangements of tuyeres
- F27D 7/02: Supplying steam, vapour, gases or liquids
- C21B 2005/005: {Selection or treatment of the reducing gases}
- Y02P 10/25: Process efficiency
- C21B: MANUFACTURE OF IRON OR STEEL (preliminary treatment of ferrous ores or scrap C22B1/00)
- F27B: FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27D: DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

To provide a method for operating a blast furnace with which the combustion efficiency of a solid fuel, such as pulverized coal, is improved, thereby making it possible to improve productivity and reduce CO2 emissions. Pulverized coal and oxygen are blown from an upstream lance 4 configured by a double tube, and LNG is blown from a downstream lance 6 on the downstream side in a hot air blast direction, so that oxygen to be used for combustion of the LNG is supplied from the upstream lance 4, and the pulverized coal whose temperature has been increased by the combustion of the LNG is combusted along with the supplied oxygen or oxygen in an air blast. When a direction perpendicular to the hot air blast direction is designated as 0°, and a downstream direction and an upstream direction therefrom in the hot air blast direction are designated as positive and negative, respectively, a blowing direction of the LNG from the downstream lance 6 with respect to the blast direction ranges from −30° to +45°, and a blowing position of the LNG from the downstream lance 6 with reference to a position at which the upstream lance 4 is inserted into a blast pipe 2 ranges from 160° to 200° in terms of a blast pipe circumferential direction angle.

## Claims

### Claim 1

A method for operating a blast furnace, in which hot air is blown into a blast furnace from a blast pipe through a tuyere, the method comprising:
using a double tube as an upstream lance for blowing a solid fuel into the blast pipe;
blowing one of the solid fuel and combustion-supporting gas from one of an inner tube of the upstream lance and a gap between the inner tube and an outer tube, and blowing the other of the solid fuel and the combustion-supporting gas from the other of the inner tube and the gap between the inner tube and the outer tube;
disposing a downstream lance on a downstream side in a blast direction of the hot air from a blowing end part of the upstream lance; and
blowing flammable gas from the downstream lance.

### Claim 2 (depends on 1)

The method for operating a blast furnace according to claim 1, wherein,
when a direction perpendicular to the blast direction of the hot air is designated as 0°, and a downstream direction and an upstream direction therefrom in the blast direction of the hot air are designated as positive and negative, respectively, a blowing direction of the flammable gas from the downstream lance with respect to the blast direction ranges from −30° to +45°.

### Claim 3 (depends on 1)

The method for operating a blast furnace according to claim 1, wherein
a blowing position of the flammable gas from the downstream lance with reference to a position at which the upstream lance is inserted into the blast pipe ranges from 160° to 200° in terms of a circumferential direction angle of the blast pipe.

### Claim 4 (depends on 1)

The method for operating a blast furnace according to claim 1, wherein
a distance of the downstream lance from the upstream lance is set to be 27 mm to 80 mm.

### Claim 5 (depends on 1)

The method for operating a blast furnace according to claim 1, wherein
a blowing speed of the flammable gas from the downstream lance is set to be 50 m/s to 146 m/s.

### Claim 6 (depends on 2)

The method for operating a blast furnace according to claim 2, wherein
a blowing position of the flammable gas from the downstream lance with reference to a position at which the upstream lance is inserted into the blast pipe ranges from 160° to 200° in terms of a circumferential direction angle of the blast pipe.

### Claim 7 (depends on 2)

The method for operating a blast furnace according to claim 2, wherein
a distance of the downstream lance from the upstream lance is set to be 27 mm to 80 mm.

### Claim 8 (depends on 3)

The method for operating a blast furnace according to claim 3, wherein
a distance of the downstream lance from the upstream lance is set to be 27 mm to 80 mm.

### Claim 9 (depends on 2)

The method for operating a blast furnace according to claim 2, wherein
a blowing speed of the flammable gas from the downstream lance is set to be 50 m/s to 146 m/s.

### Claim 10 (depends on 3)

The method for operating a blast furnace according to claim 3, wherein
a blowing speed of the flammable gas from the downstream lance is set to be 50 m/s to 146 m/s.

### Claim 11 (depends on 4)

The method for operating a blast furnace according to claim 4, wherein
a blowing speed of the flammable gas from the downstream lance is set to be 50 m/s to 146 m/s.