Burden Distribution Model

For the achievement of economical and stable blast furnace (BF) operation, the control of internal furnace state through appropriate control of the burden distribution at blast furnace top is vitally important. In this context, the study of the static behavior of the burden (such as deposition angle after charging) the dynamic behaviour of the burden (formation process of the burden distribution) is very important. By the introduction of movable armour (MA) and Bell-Less-Top (BLT) charging system and development of various in-furnace sensors, improved operation of blast furnace has been achieved. While BLT system has been applied in many blast furnaces, it is necessary to establish an efficient burden distribution control based on mathematical simulation model. It is necessary for plants to establish such burden distribution techniques, which can help to maintain adequate peripheral gas flow and a sharp central gas flow simultaneously. 

A mathematical model has been developed to simulate the trajectory of the particles along with upper and lower bound during the flight with an assumed initial stock-line profile for BLT charging system of an operating plant.  A stock profile generation algorithm has been developed (on the basis of volume balance and iterative algorithm) to evaluate the new stock line profile for typical plant charging parameters.  The model is capable of calculating the radial distribution of ore/coke layer-thickness-ratio, radial void distribution and mean particle size distribution as functions of the charging sequence and physical characteristics of the charge materials. The adjustable parameters of the model have been tuned from Bokaro BF No.1 with the plant data for furnace specific applications 

Figure 1:     (a)                                                  (b)	Figure 2:    (a)                                                    (b)
Figure 1 (a) Trajectory simulation for a prediction of chute angle for a given charge amount  (b) The formation sequence of new stock profile	Figure 2 (a) Plant measurements for calibration of the model and (b) Validation of model prediction with plant data