Koke which is produced through coal being heated in an oxygen-free atmosphere (dry distillation).
The consumption of energy follows the steel output trend. This means that energy use falls during a recession when the demand for steel, and consequently its production, declines.
The variations in consumption of coke and coke oven gas are tied to the production of ore-based steel which constitutes about two-thirds of Sweden’s total steel production. From an energy consumption viewpoint, the ore-based steel plants are wholly dominant. This is due to the fact that the coke required as a reducing agent in smelting iron ore is counted in the energy balance.
For scrap-based steel production, on the other hand, electric power is the principal energy source.
The steel industry’s use of oil, gas and electricity has been comparatively stable since 1990. Whereas the use of gas (LPG and natural gas) has increased slightly, the use of oil has declined. Previously, natural gas could only be used by the iron and steelworks in the southern part of Sweden where a distribution network for natural gas existed. Since it became possible to transport natural gas in liquid form – so-called LNG – then this energy source has been used for heat treatment furnaces at several sites across Sweden.
Energy use in the Swedish iron and steel industry.
Residual energy from the processes is utilised
Following use of the energy resources in the steel production processes, in many cases the residual heat and energy formed can be usefully employed once again. Process gases from the coking plant, blast furnace and steelworks are used for production of electricity and district heating. Heat produced in smelters and furnaces is often taken care of and fed into the district heating networks for the benefit of the neighbouring communities.