Real-Time Evaluation Technology for Level of Residual Melts in Blast Furnace Bottom

On-line estimation of the distance (= liquid surface level) of the liquid surface of residual melts (hot metal, slag) in the blast furnace from the taphole, contribution to suppression of serious trouble associated with a rise in the liquid level.

Solution Point

The conventional method was management of the "amount" of residual melts. This model enables direct monitoring of the height of the liquid surface (= liquid surface level) of residual melts (hot metal, slag), which could not be managed by the conventional technique, by estimation of the effective furnace volume, considering the void ratio of the deadman coke.
Clarifying the liquid surface level vs. the taphole position, which could not be grasped only by managing the "amount" of residual melts, reduces the risk of operational abnormalities such as slag back-flow to the tuyeres, etc.

Features 01

Expected Problems

・ We didn't realize the liquid level was rising, and production was reduced by operational abnormalities.

・ We're having furnace heat and permeability problems that just don't get any better (in some cases, a rise in the liquid level is the root cause).

Features 02

Technology highlight

Modelling of the condition in the blast furnace bottom based on model tests in JFE Steel. Calculation of the coke void ratio (see following equation) in the deadman part from the pressure balance in blast furnace bottom. Estimation of the effective volume of the hearth enables direct monitoring of the liquid surface height (= liquid level) of residual melts, which was not possible by conventional residual melts management techniques.

Features 03

Proposed Solutions (Examples)

This model has been applied to all blast furnaces in JFE Steel, improving the residual melts management method from "trend of amount" to "trend of liquid level."

The liquid level can now be known on-line, contributing to suppression of operational problems associated with abnormal rise of the liquid level.

Links 01