A Research On The Burden In Blast Furnace

The coal rate is being increased in recent years owing to the high economics of coal powder injection. To afford a framework at high temperature in a blast furnace is one of the most important functions of coke, which can't be replaced by other fuels like coal powder, so that there must be a limitation for increasing of coal rate or decreasing of coke rate. To get the maximum coal rate is one of the key research works for metallurgists in the world in recent time. The carbon loss ratio of coke increases with the increasing of the coal rate injected in blast furnace and the strength of coke decreases with the increasing of carbon loss ratio. The coke can play its role only when its strength stands up to the burden in the furnace. The main task of this work is to research the stress distribution in a blast furnace as the first step of the research on the limitation of coal rate for iron-making.Based on element balances and general differential equation, a 2-D mathematical model for simulating the stress distribution in a blast furnace has been established using equation of continuity, equation of motion and equation of state. The flow function and stress function has been deduced using difference equation. The program was designed using Microsoft Visual C++ according to the given boundary conditions of flow and stress fields.Characteristics of burden, cohesive zone and furnace lining were considered for the calculation of the stress distribution. After the works mentioned above, optimizations were made on the whole program with the relaxation factor.Following conclusions were drawn in this paper:1. There were two peak values of stress in a blast furnace owing to the geometry characteristics of the furnace lining.2. The stress depressed from center to side and rose again at the wall due to the friction between the burden and the wall of the blast furnace. With the depth in the furnace, the stress increased in the area above the cohesive zone and kept the value in the area below it. It began to change quickly again at the top of the hearth of the furnace.Beside that, several important theories drawn by other researchers were validated and used in this paper.