Method for operating blast furnace

Patent metadata

Field	Value
Publication number	US-2018023152-A1
Application number	US-201615547891-A
Country	US
Kind code	A1
Filing date	Feb 22, 2016
Priority date	Mar 2, 2015
Publication date	Jan 25, 2018
Grant date	—

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 CO 2 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.

First 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.

2 . 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°.

3 . 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.

4 . 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.

5 . 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.

6 . 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.

7 . 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.

8 . 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.

9 . 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.

10 . 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.

11 . 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.

Assignees

• Jfe Steel Corp

Inventors

• Murao Akinori
• Yamamoto Naoki
• Kawashima Tomoyuki
• Ooyama Nobuyuki

Classifications

• F27D7/02

  Supplying steam, vapour, gases or liquids · CPC title

• C21B7/00

  Blast furnaces · CPC title

• C21B2005/005

  Selection or treatment of the reducing gases · CPC title

• C21B5/003 Primary

  Injection of pulverulent coal · CPC title

• C21B5/001

  Injecting additional fuel or reducing agents · CPC title