Drainage rate and hearth liquid level estimation in absence of direct measurements in blast furnace

Abstract

The present work deals with the development of a mathematical model to provide the real-time information about important stages of the tapping operation of the iron making blast furnace. In the present work, an attempt is made to derive a generic equation for hot metal and slag drainage rate based upon the empirical approach that makes the liquid level estimation independent of the inter-dependability of the field sensors. This approach is particularly useful where direct measurements are not available. The liquid level model tracks the levels of molten iron and slag inside the hearth based on a continuous analysis of hot metal production and tapped liquid quantities, further certain assumptions are considered such as internal state of the hearth, including its geometry and the stationary state of the coke bed. Because of inaccuracies in the model and in the measurements from the process, an optimal filtering method is applied to provide the reasonable liquid level estimates. The model has been found to provide valuable information about the crucial steps in the tap cycle and is validated with the relevant process parameters with a confidence of ∼95% accuracy.