JP-7856936-B1 - Blast furnace operation methods

JP7856936B1JP 7856936 B1JP7856936 B1JP 7856936B1JP-7856936-B1

Abstract

A novel technology is disclosed that makes it possible to change the concentration distribution of reducing components inside a blast furnace during its operation. The method of operating a blast furnace according to this disclosure includes supplying hot air into the blast furnace through a hot air flow path provided in a hot air tuyere, and supplying reducing gas into the blast furnace through a reducing gas outlet provided in the hot air tuyere. Here, the hot air tuyere is provided with a plurality of reducing gas outlets. The method of operating a blast furnace according to this disclosure includes changing the flow rate of the reducing gas blown out from at least one of the reducing gas outlets.

Inventors

今野新之介
菅原翔太

Assignees

日本製鉄株式会社

Dates

Publication Date: 20260512
Application Date: 20250701
Priority Date: 20240718

Claims (7)

A method for operating a blast furnace, Hot air is supplied to the inside of the blast furnace through a hot air passage provided in the hot air tuyeres, and reducing gas is supplied to the inside of the blast furnace through a reducing gas outlet provided in the hot air tuyeres. Includes, The hot air nozzle is provided with multiple reducing gas outlets. The method of operating the blast furnace includes changing the flow rate of the reducing gas blown out from at least one of the reducing gas outlets, By reducing the flow rate of the reducing gas blown out from at least one of the plurality of reducing gas outlets while increasing the flow rate of the reducing gas blown out from at least one other reducing gas outlet, the fluctuation in the total flow rate of the reducing gas blown out from the hot air tuyere can be kept within ±0.5%. The operation method of a blast furnace.
A method for operating a blast furnace according to claim 1, The flow rate of the reducing gas blown out from at least one of the reducing gas outlets is changed according to the concentration distribution of the reducing component in the radial or circumferential direction inside the blast furnace. A method of operating a blast furnace, including [specific details omitted].
A method for operating a blast furnace according to claim 2, Of the multiple reducing gas outlets, one reducing gas outlet is located closer to the tip of the tuyere body of the hot air tuyere than the other reducing gas outlets. Depending on the concentration distribution of reducing components in the radial direction inside the blast furnace, at least one of the following (1) and (2) is performed: Blast furnace operation methods: (1) If the concentration of reducing components on the furnace wall side inside the blast furnace is lower than the target value, the amount of reducing gas supplied into the blast furnace via the reducing gas outlet provided on the tip side of the tuyere body of the hot air tuyere will be increased to bring the concentration of reducing components on the furnace wall side inside the blast furnace closer to the target value; (2) If the concentration of reducing components on the furnace wall side inside the blast furnace is higher than the target value, the amount of reducing gas supplied into the blast furnace through the reducing gas outlet provided on the tip side of the tuyere body of the hot air tuyere will be reduced to bring the concentration of reducing components on the furnace wall side inside the blast furnace closer to the target value.
A method for operating a blast furnace according to claim 2, The height position of at least one of the plurality of reducing gas outlets is above the height position of the center of the opening that serves as the outlet for the hot air passage of the tuyere body of the hot air tuyere, and the height position of at least one of the plurality of reducing gas outlets is below the height position of the center of the opening that serves as the outlet for the hot air passage of the tuyere body of the hot air tuyere. Depending on the concentration distribution of reducing components in the radial direction inside the blast furnace, at least one of the following (3) to (6) is performed: Blast furnace operation methods: (3) If the concentration of reducing components on the furnace wall side inside the blast furnace is lower than the target value, the amount of reducing gas supplied into the blast furnace through the reducing gas outlet located at the upper height position is increased to bring the concentration of reducing components on the furnace wall side inside the blast furnace closer to the target value; (4) If the concentration of reducing components on the furnace wall side inside the blast furnace is higher than the target value, the amount of reducing gas supplied into the blast furnace through the reducing gas outlet located at the upper height position is reduced to bring the concentration of reducing components on the furnace wall side inside the blast furnace closer to the target value; (5) If the concentration of reducing components in the center of the blast furnace is lower than the target value, increase the amount of reducing gas supplied into the blast furnace through the reducing gas outlet located at the lower height position to bring the concentration of reducing components in the center of the blast furnace closer to the target value: (6) If the concentration of reducing components in the center of the blast furnace is higher than the target value, the amount of reducing gas supplied into the blast furnace via the reducing gas outlet located at the lower height position is reduced to bring the concentration of reducing components in the center of the blast furnace closer to the target value.
A method for operating a blast furnace according to any one of claims 1 to 4 , Reducing gas is supplied into the blast furnace through a plurality of reducing gas injection ports provided in the hot air tuyeres. A method of operating a blast furnace, including [specific details omitted].
A method for operating a blast furnace according to any one of claims 1 to 4 , Reducing gas is supplied into the blast furnace through a plurality of reducing gas injection lances provided in the hot air tuyeres. A method of operating a blast furnace, including [specific details omitted].
A method for operating a blast furnace according to any one of claims 1 to 4 , Reducing gas is supplied into the blast furnace through at least one reducing gas injection port and at least one reducing gas injection lance provided in the hot air tuyer. A method of operating a blast furnace, including [specific details omitted].

Description

This application discloses a method for operating a blast furnace. Reducing CO2 emissions in the steelmaking process is being considered. For example, when producing pig iron in a blast furnace, it is possible to use a reducing gas such as hydrogen gas instead of some of the reducing agent such as coke. Patent Document 1 discloses a method of supplying reducing gas to a blast furnace in which a lance for injecting reducing gas is placed inside or on the wall of the hot air passage of the hot air tuyer, and the reducing gas is injected through the lance. Although not intended for injecting reducing gas, Patent Document 2 discloses a method in which a fuel injection lance is inserted into the wall of the hot air tuyer, and pulverized coal is injected into the blast furnace as fuel through the fuel injection lance. Patent No. 4997734Patent No. 5840202 This diagram provides a schematic example of a blast furnace configuration. Some components of the blast furnace are omitted from the diagram.This diagram schematically shows an example of the configuration of one of the multiple reducing gas outlets installed in a hot air tuyer.This diagram schematically shows an example of the configuration of one of the multiple reducing gas outlets installed in a hot air tuyer.This diagram schematically shows an example of the configuration of one of the multiple reducing gas outlets installed in a hot air tuyer.This diagram schematically shows an example of the configuration of one of the multiple reducing gas outlets installed in a hot air tuyer.This diagram schematically shows an example of the configuration of one of the multiple reducing gas outlets installed in a hot air tuyer.This diagram schematically shows an example of the configuration of one of the multiple reducing gas outlets installed in a hot air tuyer.This diagram schematically shows an example of the configuration of multiple reducing gas outlets in a hot air tuyer.This diagram schematically shows an example of the configuration of multiple reducing gas outlets in a hot air tuyer.This diagram schematically shows an example of the configuration of multiple reducing gas outlets in a hot air tuyer.This shows an example of the flow when changing the concentration distribution of reducing components inside a blast furnace.This shows an example of the flow when changing the concentration distribution of reducing components inside a blast furnace.This shows an example of the flow when changing the concentration distribution of reducing components inside a blast furnace.This shows the concentration distribution of hydrogen molecules based on the simulation results.This shows the concentration distribution of hydrogen molecules based on the simulation results.This shows the concentration distribution of hydrogen molecules based on the simulation results.This shows the concentration distribution of hydrogen molecules based on the simulation results.This shows the concentration distribution of hydrogen molecules based on the simulation results.This shows the concentration distribution of hydrogen molecules based on the simulation results.This shows the concentration distribution of hydrogen molecules based on the simulation results.This shows the concentration distribution of hydrogen molecules based on the simulation results.This shows the concentration distribution of hydrogen molecules based on the simulation results. The following describes one embodiment of the blast furnace operation method of this disclosure. However, the blast furnace operation method of this disclosure is not limited to the following embodiment. 1. Blast Furnace Operation Method As shown in Figures 1 to 7 and Figures 8A to 8C, an operation method for a blast furnace 100 according to one embodiment includes supplying hot air to the interior of the blast furnace 100 via a hot air passage 12 provided in the hot air tuyere 10, and supplying reducing gas to the interior of the blast furnace 100 via a reducing gas outlet 13x provided in the hot air tuyere 10. Here, the hot air tuyere 10 is provided with a plurality of reducing gas outlets 13x. Furthermore, an operation method for a blast furnace 100 according to one embodiment includes changing the flow rate of the reducing gas blown out from at least one of the reducing gas outlets 13x. 1.1 Hot Air Tuyeres As shown in Figure 1, the hot air tuyeres 10 are provided, for example, below the lower end 101ax of the shaft of the blast furnace 100 and above the tapping port 102. "Lower end of shaft" refers to the boundary between the shaft 101a and the furnace belly (belly) 101b. "Shaft" refers to the part above the furnace belly 101b, where the furnace diameter usually increases from top to bottom. "Furnace belly" refers to the part below the shaft and above the bellows (bosch) 101c, where the furnace diameter is usually the largest. The furnace diameter (diameter) of the furnace belly 101b may be, for example, 5m or more and 20m or less, or 10m or more a