Method for manufacturing molten iron with electric arc furnace

Patent metadata

Field	Value
Publication number	US-2022403478-A1
Application number	US-202017772675-A
Country	US
Kind code	A1
Filing date	Oct 14, 2020
Priority date	Nov 6, 2019
Publication date	Dec 22, 2022
Grant date	—

Abstract

A method for manufacturing molten iron by melting a cold iron source in an electric arc furnace having a carbonaceous material-injecting device. The method includes, in the carbonaceous material-injecting device, while a carbonaceous material is injected with a carrier gas through a central portion of the carbonaceous material-injecting device, injecting a fuel and a combustion-supporting gas through respective outer peripheral portions of the carbonaceous material-injecting device. The carbonaceous material injected through the central portion passes through a cylindrical combustion flame generated by a combustion reaction between the fuel and the combustion-supporting gas and is injected into molten slag and molten iron.

First claim

1 . A method for manufacturing molten iron with an electric arc furnace, in which a cold iron source is melted to manufacture molten iron, the electric arc furnace having a carbonaceous material-injecting device, the method comprising:
in the carbonaceous material-injecting device, while a carbonaceous material is injected with a carrier gas through a central portion of the carbonaceous material-injecting device, injecting a fuel and a combustion-supporting gas through respective outer peripheral portions of the carbonaceous material-injecting device, wherein the carbonaceous material injected through the central portion passes through a cylindrical combustion flame generated by a combustion reaction between the fuel and the combustion-supporting gas and is injected into molten slag and molten iron.

2 . The method for manufacturing molten iron with an electric arc furnace according to claim 1 , wherein injection flow velocities of the fuel and the combustion-supporting gas in the carbonaceous material-injecting device are higher than an injection flow velocity of the carrier gas of the carbonaceous material in the carbonaceous material-injecting device.

3 . The method for manufacturing molten iron with an electric arc furnace according to claim 1 , wherein the combustion-supporting gas is supplied such that an oxygen ratio with respect to an amount of the fuel supplied into the carbonaceous material-injecting device is in a range of 1.0 to 1.1.

4 . The method for manufacturing molten iron with an electric arc furnace according to claim 1 , wherein the carbonaceous material-injecting device has a structure in which a carbonaceous material injection pipe, a fuel injection pipe, and a combustion-supporting gas injection pipe are arranged, in this order, coaxially from the central portion of the carbonaceous material-injecting device.

5 . The method for manufacturing molten iron with an electric arc furnace according to claim 1 , wherein injection flow velocities of the fuel and the combustion-supporting gas in the carbonaceous material-injecting device are in a range of 100 m/s to 500 m/s.

6 . The method for manufacturing molten iron with an electric arc furnace according to claim 1 , wherein a combustion rate of the fuel in the carbonaceous material-injecting device is 400 Mcal/h or more.

7 . The method for manufacturing molten iron with an electric arc furnace according to claim 1 , wherein a ratio of a combustion rate of the fuel to an injection rate of the carbonaceous material in the carbonaceous material-injecting device is 0.1 Mcal/kg or more.

8 . The method for manufacturing molten iron with an electric arc furnace according to claim 2 , wherein the combustion-supporting gas is supplied such that an oxygen ratio with respect to an amount of the fuel supplied into the carbonaceous material-injecting device is in a range of 1.0 to 1.1.

9 . The method for manufacturing molten iron with an electric arc furnace according to claim 2 , wherein the carbonaceous material-injecting device has a structure in which a carbonaceous material injection pipe, a fuel injection pipe, and a combustion-supporting gas injection pipe are arranged, in this order, coaxially from the central portion of the carbonaceous material-injecting device.

10 . The method for manufacturing molten iron with an electric arc furnace according to claim 3 , wherein the carbonaceous material-injecting device has a structure in which a carbonaceous material injection pipe, a fuel injection pipe, and a combustion-supporting gas injection pipe are arranged, in this order, coaxially from the central portion of the carbonaceous material-injecting device.

11 . The method for manufacturing molten iron with an electric arc furnace according to claim 8 , wherein the carbonaceous material-injecting device has a structure in which a carbonaceous material injection pipe, a fuel injection pipe, and a combustion-supporting gas injection pipe are arranged, in this order, coaxially from the central portion of the carbonaceous material-injecting device.

12 . The method for manufacturing molten iron with an electric arc furnace according to claim 2 , wherein injection flow velocities of the fuel and the combustion-supporting gas in the carbonaceous material-injecting device are in a range of 100 m/s to 500 m/s.

13 . The method for manufacturing molten iron with an electric arc furnace according to claim 3 , wherein injection flow velocities of the fuel and the combustion-supporting gas in the carbonaceous material-injecting device are in a range of 100 m/s to 500 m/s.

14 . The method for manufacturing molten iron with an electric arc furnace according to claim 8 , wherein injection flow velocities of the fuel and the combustion-supporting gas in the carbonaceous material-injecting device are in a range of 100 m/s to 500 m/s.

15 . The method for manufacturing molten iron with an electric arc furnace according to claim 2 , wherein a combustion rate of the fuel in the carbonaceous material-injecting device is 400 Mcal/h or more.

16 . The method for manufacturing molten iron with an electric arc furnace according to claim 3 , wherein a combustion rate of the fuel in the carbonaceous material-injecting device is 400 Mcal/h or more.

17 . The method for manufacturing molten iron with an electric arc furnace according to claim 8 , wherein a combustion rate of the fuel in the carbonaceous material-injecting device is 400 Mcal/h or more.

18 . The method for manufacturing molten iron with an electric arc furnace according to claim 2 , wherein a ratio of a combustion rate of the fuel to an injection rate of the carbonaceous material in the carbonaceous material-injecting device is 0.1 Mcal/kg or more.

19 . The method for manufacturing molten iron with an electric arc furnace according to claim 3 , wherein a ratio of a combustion rate of the fuel to an injection rate of the carbonaceous material in the carbonaceous material-injecting device is 0.1 Mcal/kg or more.

20 . The method for manufacturing molten iron with an electric arc furnace according to claim 8 , wherein a ratio of a combustion rate of the fuel to an injection rate of the carbonaceous material in the carbonaceous material-injecting device is 0.1 Mcal/kg or more.

Assignees

• Jfe Steel Corp

Inventors

• Miwa Yoshihiro
• Tsutsumi Koichi
• Sumi Ikuhiro

Classifications

• C21B11/10 Primary

  in electric furnaces · CPC title

• C21C2005/366

  Foam slags · CPC title

• C21C5/36

  Processes yielding slags of special composition · CPC title

• C21C2005/5276

  with liquid or solid rest, e.g. pool, "sumpf" · CPC title

• F27D3/16

  Introducing a fluid jet or current into the charge (F27D3/18 takes precedence) · CPC title