Research On The Model For Bell-less Charging Of Blast Furnace

Charging system of blast furnace (BF) is one of the four daily operating systems. It has direct effect on the initial distribution of burden in BF. The distribution determines the permeability of BF, distribution of gas and reaction between gas and solid. The permeability and the reaction are the main factors to affect utilization ratio of gas, quality and quantity of hot metal, smooth operation and stability of BF. So, based on the main charging rules of bell-less BF, the model of the relation between charging system and initial distribution of burden is helpful to practical production.In this paper, a mathematical model of bell-less charging of single hopper BF is founded on the rules of charging system, with the knowledge of kinematics, mathematics, technics of BF and computer technology. A physical experimental model is created according to the top and the charging system of actual 2500m3 BF. It is used to validate the trajectory of burden. The main contents of the paper are listed as follow:(1) The paper proposed the academic background and significance of the topic and explained the significance of the mathematical model to practical production of BF. The current situation and development trend of the field at home and abroad have done a review, and the main content and innovative points of the paper have been proposed.(2) The paper in detail explains the history of BF charging equipments and the variety of distributing methods, systematically parses the process from burden leaving the hopper to form new burden surface and analyzes the factors which have effects on the new burden surface.(3) Seven models which are made up of the whole mathematical model are as follow: model of gate valve and the velocity of burden leaving it, movement of burden on the chute, burden trajectory, burden surface and modifiability of burden descent to the burden surface and mixed layers to burden surface. For an especial charging method which comes from a 2500m3single hopper BF, the mathematical model calculates the burden surface and radial ratio of ore to coke.(4) Based on a 2500m3single hopper BF, a reduce model is founded. Before experiment of burden trajectory, the diameters of material are determined by a special experiment. The property of coke and sinter are measured. The experiment of burden trajectory proves that the method of burden trajectory in the mathematical model is right. (5) In the end, the research on the topic was systematically reviewed. Based on the current status of research on the BF charging model, the prospects about the subject are also pointed out.