HEARTH SIZE TRENDS IN NEW AND MODERNIZED BLAST FURNACES

Abstract

The efficiency and effectiveness of blast-furnace smelting largely depends on the parameters hearth and its mode of operation. The purpose work is to identify trends in the design hearth of blast furnaces. To achieve the goals set, we used project and practical information on the issue under study for a long period of time from the 70s of the last century to the last decade of the XXI century. To assess the changes that have occurred, in addition to the absolute dimensions hearth (diameter, height and relative useful volume hearth to the countercurrent part of the furnace), indicators were used that indirectly assess the load hearth volume on the heat supply of one tuyere hearth and load hearth volume on the exhaust system blast furnace. The proposed indicators determine share useful volume of the hearth per one air tuyere, and the share of the useful volume of the hearth related to one cast-iron tap-hole. It is shown that the transition from designing high hearths with dg > 6 m to hearths with dg < 6 m occurred as early as in the 70s of the XX century. The absolute height hearth modern furnaces medium (dg = 11—12 m) and large (dg > 12 m) volume is in the range of 4,5÷5,4 m with slow growth with an increase in the useful volume of furnaces. The range fluctuations relative useful volume hearth relative to the volume countercurrent part furnaces within 0,15 ÷ 0,22 and its certain increase with an increase in the useful volume of the units is established. The reason for the absence of changes in Vkg /Vpr for the reconstructed typical Soviet furnaces, despite increase in the height hearth, is the preservation excessive height countercurrent part of the furnaces. When designing the design of the hearth of new and upgrading existing furnaces, it is recommended to maintain the values ​​of Vkg /nf and Vkg/nchl at the minimum possible level due specifics installation of tuyere devices and maintenance exhaust system of blast furnaces.