SSAB and Linde Gas, formerly AGA, have been working together to investigate the possibility of mixing oxygen in the combustion air to the heaters at SSAB’s blast furnace 3 in Luleå, Northern Sweden.

Linde said the results are positive and show that oxygen enrichment makes it possible to reduce the total amount of combustion air in the heaters and to a greater extent utilise blast furnace gas for the energy supply.

“The method of oxygen in the combustion air to the heaters has been brought to the fore in that the maintenance project at the coking plant reduces the supply of coke gas for a period,” David Bellqvist, Energy Coordinator at SSAB, who has been working on the project, explained.

“We will therefore introduce the technology at blast furnace 3 during the year.”

During the maintenance project at the coking plant, the so-called publisher will be replaced, and during that time the coking plant will run at half speed.

Screenshot 2020-10-13 at 10.24.09

Source: SSAB/Tommy Höjsten

This means that the availability of cooking gas is also halved and for the heaters this leads to a sharp reduction and a subsequent lowering of the temperature of the blast air.

With the help of oxygen enrichment in the heaters, the effects on the coal and coke consumption in the blast furnace can be minimised and a relatively normal production maintained.

Without oxygen enrichment, the consumption of coal and coke in the blast furnace would increase by about 10,000–12,000 tonnes during the change of publisher, but with the help of oxygen enrichment, that figure can be reduced to about 7,000–8,000 tonnes, ie around 25-30% lower.

Even after the change of publisher, the oxygen enrichment will mean an opportunity for greater flexibility in energy use and thereby potential for energy savings at SSAB Luleå.