Importance of Hearth, Dead man and Tapping in Blast Furnace Operation Apr13

Importance of Hearth, Dead man and Tapping in Blast Furnace Operation...

Importance of Hearth, Dead man and Tapping in Blast Furnace Operation  A trend of deterioration in ore quality is seen these days with the increasing demand for iron ore. The deterioration in ore quality is accompanied with higher quantities of slag which in turn affects burden descent and liquid flow through the hearth. These conditions provide a catalyst for lining wear mechanism with bosh, stack and hearth linings coming under additional stress. Tapping in the blast furnace is adversely affected and trough and runners in the cast house get under strain due to higher slag volume. All these put increased pressure on blast furnace operations. The poor quality of iron ore affects the operation of the blast furnace in the following way. Slag volume – Poor quality of iron ores bring into the furnace higher quantities of impurities resulting into increase in the slag volumes. Heat load – The furnace thermal condition undergoes changes since a large quantity of heat is required to melt the additional slag as well as to keep it in proper fluid state for its drainage. This introduces higher heat loads inside the blast furnace. Coke rate and productivity – Increasing slag volumes needs a higher fuel input into the furnace, and where pulverized coal injection rates are already running at optimum, this results into a higher coke rate. Higher coke means introduction of higher amount of ash in the furnace resulting into further increase in the slag volume. This has got a deteriorating effect on the productivity of the furnace. Process stability – The deterioration in the ore quality affects the process stability adversely and has an unfavourable effect on the smooth running of the blast furnace. Due to the above factors, the production process in the blast furnace...