MODELING ACCRETION LAYER THICKNESS IN THE BLAST FURNACE STACK

摘要

The main factors behind accretion formation in the blast furnace are known and impact of accretions on process variables and sensor readings has also been extensively investigated over the years. However, accretion thermal and mechanical properties, in particular general and systematic description of these as function of location and buildup mechanism, are still open to investigation. Knowledge of thermal properties and their temperature dependence are imperative for any mathematical model of accretion formation. In the literature, models of stack accretions are few and important issues in conjunction with uniqueness, stability and measurement noise are mostly disregarded. Quite a few contributions are focused on hearth wear and scull prediction and their methodology can, at least in principle, be generalized to stack accretion estimation. Here, a simple one-dimensional, dynamic model was formulated on basis of the sideways heat equation in the refractory region and steady state approximation in the accretion region. Simulated, noisy input signals were used to illustrate the stability against measurement errors and model response to abrupt accretion dislocation. The results indicate model feasibility by both of these criteria.