Probes, Instruments and measurements for Monitoring of Blast Furnace Jun28

Probes, Instruments and measurements for Monitoring of Blast Furnace...

Probes, Instruments and measurements for Monitoring of Blast Furnace A blast furnace (BF) works with the principle of countercurrent gas to solid heat exchange from tuyere raceway to the stock line and of a countercurrent oxygen (O2) exchange from fusion zone to the stock line. Solid burden materials consisting of ferrous materials (iron ore, sinter, and pellets), coke, and fluxing materials are charged into the top of the furnace, while air normally enriched with O2, and sometimes with auxiliary fuels is fed through the tuyeres near the bottom of the furnace. The usual retention time of the ferrous burden materials in the furnace may be as long as 8 hours, while that of the gas is a few seconds. However, the residence time of the coke in the hearth is much longer usually ranging from 1 week to 4 weeks. The liquid hot metal (HM) and liquid slag are tapped at regular intervals through a number of tapholes situated at the bottom of the furnace. The slag is separated from the hot metal which is handled through HM ladles. A blast furnace need to be operated with high productivity and low fuel rate in a flexible, stable and high efficiency manner and must have a long campaign life. The blast furnace is often referred to as black box because of the terms such as the furnace condition and furnace heat level which is currently in dominant use as well as since the blast furnace process has many unknown areas. The reason seems to be due to the difficulty in measurement, because, in a blast furnace, three phases of gas, solid, and liquid coexist, the reaction proceeds non-uniformly in radial direction, the process is accompanied by a time dependent variation, and the parameters to be...