A review on liquid level measurement techniques using mathematical models and field sensors in blast furnace

Stable blast furnace operation requires proper drainage of liquid from the hearth. The estimation of drainage rate and hearth liquid level are of utmost importance for understanding the underlying hearth phenomena. The present review gives an insight of the need for measurement of the hearth liquid level and further throws light on various methods of estimation of hearth liquid level in-depth, which is primarily divided into 2 categories namely; model-based estimation and sensor-based estimation. Although the model-based estimation and sensor-based estimation have their own advantages and disadvantages, an integrated system comprising of both methods could potentially facilitate operators to reveal the state of hearth, which is unless not available with the implementation of a single method of estimation. Furthermore, the challenges in the estimation and the prospects for determining the reliable hearth liquid level measurement in blast furnace are discussed. The article is presented to give prospect of encountering the drift occurring in estimation of liquid level, which leads to inaccurate prediction and simulation with the industrial blast furnace. Lastly, the article gives recommendation for improving the liquid level estimation methods in blast furnace.