Liquid level detection method and detection apparatus for the same, molten material liquid level detection method and detection apparatus for the same, and method for operating vertical furnace

Patent metadata

Field	Value
Publication number	US-12584690-B2
Application number	US-202218274814-A
Country	US
Kind code	B2
Filing date	Jan 13, 2022
Priority date	Feb 3, 2021
Publication date	Mar 24, 2026
Grant date	Mar 24, 2026

Abstract

A molten material liquid level detection method that can detect a liquid level of molten material from a residual amount of the molten material with high accuracy and a method for operating a vertical furnace by using the detection method. The molten material liquid level detection method detects a liquid level of molten material remaining in a bottom portion of a vertical furnace after end of discharge of a molten material. The molten material liquid level detection method includes calculating a void fraction of the solid-filled structure, and detecting a liquid level of the molten material after the end of the discharge by using the calculated void fraction and a residual amount of the molten material after the end of the discharge.

First claim

The invention claimed is:

1 . A molten material liquid level detection method for detecting a liquid level of molten material remaining in a bottom portion of a vertical furnace after an end of discharge of the molten material, the vertical furnace generating high-temperature reducing gas by burning carbon by using oxygen-containing gas blown through a lower portion of the vertical furnace, producing the molten material by causing the high-temperature reducing gas to melt and reduce an iron source raw material that is charged through a furnace top of the vertical furnace and forms a solid-filled structure in the vertical furnace, and discharging the molten material through a taphole of the vertical furnace, the molten material liquid level detection method comprising:
calculating a void fraction of the solid-filled structure; and detecting the liquid level of the molten material after the end of the discharge based on the calculated void fraction and a residual amount of the molten material after the end of the discharge, wherein the void fraction of the solid-filled structure is calculated based on an inclination angle of a liquid surface of the molten material at the end of the discharge of the molten material through the taphole.

2 . The molten material liquid level detection method according to claim 1 , wherein the void fraction is calculated based on a viscosity of the molten material calculated from a component concentration of the discharged molten material and a temperature of the molten material.

3 . The molten material liquid level detection method according to claim 1 , wherein the void fraction is calculated based on a discharge speed at the end of the discharge of the molten material calculated from a discharge amount, a discharge period, and an initial discharge speed of the discharge of the molten material.

4 . A method for operating a vertical furnace, the method comprising, in a case where the liquid level detected by the molten material liquid level detection method according to claim 1 exceeds a predetermined threshold value, performing at least one of an operating action for lowering a production speed of the molten material and an operating action for discharging the molten material.

5 . A molten material liquid level detection apparatus for detecting a liquid level of molten material remaining in a bottom portion of a vertical furnace after an end of discharge of the molten material, the vertical furnace generating high-temperature reducing gas by burning carbon by using oxygen-containing gas blown through a lower portion of the vertical furnace, producing the molten material by causing the high-temperature reducing gas to melt and reduce an iron source raw material that is charged through a furnace top of the vertical furnace and forms a solid-filled structure in the vertical furnace, and discharging the molten material through a taphole of the vertical furnace, the molten material liquid level detection apparatus comprising a liquid level detection unit that calculates a void fraction of the solid-filled structure and detects the liquid level of the molten material after the end of the discharge based on the calculated void fraction and a residual amount of the molten material after the end of the discharge,
wherein the liquid level detection unit calculates the void fraction of the solid-filled structure based on an inclination angle of a liquid surface of the molten material at the end of the discharge of the molten material through the taphole.

6 . The molten material liquid level detection apparatus according to claim 5 , wherein the liquid level detection unit calculates the void fraction based on a viscosity of the molten material calculated from a component concentration of the discharged molten material and a temperature of the molten material.

7 . The molten material liquid level detection apparatus according to claim 5 , wherein the liquid level detection unit calculates the void fraction based on a discharge speed at the end of the discharge of the molten material calculated from a discharge amount, a discharge period, and an initial discharge speed of the discharge of the molten material.

8 . A molten material liquid level detection apparatus for detecting a liquid level of molten material remaining in a bottom portion of a vertical furnace after an end of discharge of the molten material, the vertical furnace generating high-temperature reducing gas by burning carbon by using oxygen-containing gas blown through a lower portion of the vertical furnace, producing the molten material by causing the high-temperature reducing gas to melt and reduce an iron source raw material that is charged through a furnace top of the vertical furnace and forms a solid-filled structure in the vertical furnace, and discharging the molten material through a taphole of the vertical furnace, the molten material liquid level detection apparatus comprising a processor configured to execute the steps of:
calculating a void fraction of the solid-filled structure; and detecting the liquid level of the molten material after the end of the discharge based on the calculated void fraction and a residual amount of the molten material after the end of the discharge, wherein the void fraction of the solid-filled structure is calculated based on an inclination angle of a liquid surface of the molten material at the end of the discharge of the molten material through the taphole.

Assignees

• Jfe Steel Corp

Inventors

• KAWASHIRI Yuki
• Yamamoto Tetsuya
• ICHIKAWA Kazuhira
• Nouchi Taihei

Classifications

• G01F23/22

  by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water (involving the use of floats G01F23/30) · CPC title

• F27D21/0028

  Devices for monitoring the level of the melt · CPC title

• F27D21/02

  Observation or illuminating devices · CPC title

• C21B5/006

  Automatically controlling the process · CPC title

• F27D21/00

  Arrangement of monitoring devices; Arrangement of safety devices · CPC title