Iron and Steel Overview: Energy Consumption

energy_consumption

The steel industry consumes close to 1.5 quads/year of energy. Coal contributes the largest energy share in the iron and steel industry. Over 95% of coal use goes to the coke ovens, the remaining 5% goes to various uses including on-site electric power generation. Some of the coal energy from the coke ovens is ultimately converted to coke oven gas and blast furnace gas which is used as an internally generated fuel. The next largest fuel used is natural gas used primarily in heating and annealing furnaces but also for blast furnace and basic oxygen process. (BOP) injection and boilers and cogeneration. The use of natural gas for blast furnace injection has increased substantially in the last several years.

Electricity is the third largest energy source, on a net energy delivered basis, and is used primarily in the electric arc furnaces. About 80% of electricity consumed is purchased, the rest is generated on site. Fuel oil is also used, predominantly for blast furnace injection and boiler use.

Glossary

Coke Oven Gas – A fuel produced and recovered during the production of coke from coal. The heating value of coke oven gas, whose major constituents are hydrogen and methane, is about 500 Btu/scf. About 40% of the recovered coke oven gas is used in coke production itself with the remaining portion used primarily in heating and annealing furnaces, boilers, and other heating applications. In 1994, the industry consumed 137 trillion Btu of coke oven gas compared to 472 trillion Btu supplied by natural gas.

Blast Furnace Gas – A by-product low-Btu fuel gas (95 Btu/scg) produced in the blast furnace, blast furnace gas is produced in enormous quantities – 2 1/2 to 3 1/2 tons per ton of pig iron produced. Most blast furnace gas is used for boilers and other heating applications, though a large share is used to heat the blast air stoves for the blast furnace. In 1994, the industry consumed 205 trillion Btu of blast furnace gases.

Natural Gas Use in the Steel Industry

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Electricity Consumption – The table shows average electrical consumption per ton of product for various integrated mill operations. Average power consumption at an integrated mill is about 475 kWh/ton.

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