Technology of Blast-Furnace Smelting of Iron using Pulverized Coal at the NLMK
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TECHNOLOGY OF BLAST-FURNACE SMELTING OF IRON USING PULVERIZED COAL AT THE NLMK S. V. Filatov,1 V. S. Listopadov,2 A. Yu. Sorokin,3 S. V. Myasoedov,4 V. N. Titov,5 and S. A. Zagainov6
UDC 669.162
The problems of using pulverized coal to save coke during iron smelting in the NLMK blast furnaces are considered. The iron smelting technology was implemented in two stages: (i) commissioning of the pulverized-coal preparation and charging system and (ii) selection of charging system and blast conditions that ensure the maximum utilization of pulverized coal and required output. An analysis of the dynamics in the consumption of coke and fuel additives showed that the total fuel carbon consumption has decreased, despite the difference in the amount of carbon charged with natural gas and pulverized coal. The calculations based on a mathematical model showed that with increase in the consumption of pulverized coal and decrease in the consumption of natural gas, the gas-to-coke replacement ratio increases by 0.09 kg of coke per 1 m3 of natural gas on average. Keywords: blast furnace, coke, pulverized coal, natural gas, smelting rate, total carbon consumption, pressure differential.
According to assessment based on the data published in [1], the consumption of total fuel carbon in blast furnaces of leading iron producers such as ММК, Severstal, EVRAZ NTMK, and NLMK is 418–430 kg/ton of iron. The minimum coke consumption in NLMK blast furnaces was sometimes 320 kg/ton of iron when using up to 150 kg of pulverized coal fuel (PCF). The minimum specific coke consumption without the use of PCF (380 kg/ton of iron) was achieved at the EVRAZ NTMK [2]. The use of PCF to save coke is a strategic approach to reducing the energy inputs to iron smelting in blast furnaces (BF) [3–5]. With the PCF-to-coke replacement ratio equal to 0.9–1.0 kg of coke per 1 kg of PCF and the coal consumption per ton of skip coke equal to 1.4–1.6 ton, the use of PCF at the NLMK made it possible to change the coal supply structure and to reduce the total coal consumption [6–8]. The iron smelting technology allowed the NLMK to decrease the specific coke consumption by more than 80 kg/ton of iron. The average coke consumption in 2012–2013 was 425 kg/ton of iron. It reduced to 336 kg/ton of iron in 2019 after changing over to PCF in four blast furnaces. The specific carbon consumption decreased from 426 kg/ton in 2011–2012 to 420 kg/ton in 2018–2019. PCF and natural gas (NG) are considered as carbon additives. One kilogram of carbon accounts for 3.75 m 3 of hydrogen in natural gas and just 0.40–0.45 m 3 of hydrogen (determined by element analysis) in PCF. The total 1 2 3 4 5 6
Novolipetsk Steel, Lipetsk, Russia; e-mail: [email protected].
Novolipetsk Steel, Lipetsk, Russia; e-mail: [email protected]. Novolipetsk Steel, Lipetsk, Russia; e-mail: [email protected].
Novolipetsk Steel, Lipetsk, Russia; e-mail: [email protected].
Novolipetsk Steel, Lipetsk, Russia; Lipetsk State Technical University, Lipetsk, Russia; e-mail: [email protected].
Novolip
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