Sweden-headed steel producer SSAB has disclosed the test results of using biocoal in the blast furnace at the SSAB Brahestad steelworks in Finland. Tests show that up to a ten percent biocoal blend is possible, which would reduce fossil carbon dioxide (CO2) emissions by 100 000 tonnes a year. The challenge, however, is to get enough biocoal.
Carbon dioxide (CO2) emissions from SSAB Brahestad steel mill in Finland come mainly from iron production, as fossil carbon is used as the raw material in the blast furnace (BF) process. SSAB’s long-term goal is to create a completely new technology for steel production through the HYBRIT project, where the fossil carbon is replaced by hydrogen (H2). Emissions then consist of water instead of CO2 and SSAB’s goal is to reduce CO2 emissions to zero by 2045.
The new technology is intended to be put into operation in Brahestad in the 2040s. However, in the meantime, SSAB is already developing and testing solutions that reduce emissions before the new technology is introduced. the use of biocoal appears to be a potential way to reduce emissions from steel production. In addition, coal will be needed in steel production even when the new technology is in use.
Biocoal in the blast furnace
During the past year, SSAB Brahestad has participated in a collaborative project within the framework of the FOR & MET project together with VTT Technical Research Centre of Finland and the University of Oulu. The project investigated the utilization of by-products from the forest industry as a raw material in the blast furnace (BF) in which the pulverised coal for injection (PCI) coal was replaced by with biocoal.
At SSAB Brahestad, the first test was carried out in August 2018 and lasted for eight hours. During the test, a truckload of biocoal went through the raw material BF process. In practice, this meant that four percent of the fossil PCI coal was replaced with biocoal.
The second test was conducted during May 2019 and lasted nine days. In that test, as much as ten percent of the injected PCI coal was replaced with biocoal, and 820 tonnes or about 20 truckloads of biocoal went through the raw material process.
Up to 20 percent without equipment modifications
According to SSAB, the tests show that at least ten percent of the fossil PCI coal needed for the blast furnace process could currently be replaced by biocoal. Continuous use at 10 percent would mean reducing fossil CO2 emissions by 100 000 tonnes per annum.
SSAB’s own laboratory tests have shown that, with current technical solutions, up to 20 percent of the fossil PCI coal can be replaced by biocoal. It may be possible to increase the proportion further, but in this case changes in the equipment are required.
Lack of finished biocoal
Thus, an exact figure for how much of the PCI coal can be replaced by biocoal cannot be ascertained yet. SSAB says that further tests are not intended to be carried out in the immediate future due to the difficulty in obtaining enough biocoal.
The continuous use of biocoal with a share of only ten percent would require an annual production of about 35 000 tonnes of biocoal. At present, it is difficult to find a Finnish operator who can supply so much biocoal.
