Regularity reveal of joint sinter and pellets inflow from silo of chute type top charging device into the BF mouth space by physical simulation

Abstract

A uniform distribution of burden along blast furnace circumference is an important condition for its operation with high productivity and low coke specific rate. This condition is difficult to realize with bell-less charging device of chute type. To reveal rational regimes of burden components charging into the blast furnace mouth space providing most uniform inflow of the burden components by mass, a physical simulation was realized at a laboratory facility of compact bell-less charging device of chute type, manufactured in scale 1:5 relating the linear dimensions of the PAO MMK blast furnaces Nos 2, 4 and 6 charging devices. Succession the burden components charging was being changed by pellets and additional materials supply regimes into the cilo of the bell-less charging device. As a result of the simulation dependences of the burden rational distribution on the priority and uniformity of iron ore materials inflow from the burden cilo at pellets content in them from 10 till 90% were determined. The burden components rational charging regimes were revealed depending on the heat conditions. At blast furnace running with scull it is reasonable to charge the pellets into the lower part of the bell-less charging device cilo. This will provide their inflow into the nearwall area of the furnace mouth, that enables to eliminate the scull during the furnace running. At the pellets share of 50% of the burden iron ore part, by placing of them in the bell-less charging device cilo lower part and the chure moving from periphery to center, the peripherial zone of the furnace mouth will be formed from 82% of pellets and 18% of sinter. New regimes of iron ore materials elaborated, which enable to improve uniformity of their circumference distribution. The highest value of iron ore materials inflow mass uniformity index was registered at the following sequence of the burden components charging into the bell-less charging device cilo: 25% of sinter at the burden cilo bottom, next pellets and additional materials, next charging of the 75% left sinter. At the pellets content of 30–38% of iron ore raw materials, the distribution uniformity index value exceeded 0.75.