Ovako has become the first company to successfully conduct a full-scale trial using hydrogen to heat steel before rolling, an advance that could significantly reduce greenhouse gas emissions from the industry.
In collaboration with Linde Gas, Swedish steel maker Ovako conducted a trial in which the metal alloy was heated to 1200oC using hydrogen instead of LPG (liquefied petroleum gas) before rolling at the mill in Hofors.
Subsequent testing of the steel showed that heating with hydrogen does not affect the quality. The company believes that with the right conditions it could introduce hydrogen heating for furnaces at all its rolling mills.
A spokesperson from Ovako told The Engineer that LPG and hydrogen behave differently in ignition and combustion systems. The company is using the same fuel delivery system for both fuels, leading to a change in the company’s control philosophy to achieve the same heating performance.
Ovako has modified the software program used in its control system, with changes made to account for mass flow calculations, ratio control and power control.
According to the spokesperson, the control system switches smoothly and efficiently between fuels with no process downtime or transient oscillations, which describe the variation in pressure that could take place when stepping from one pressure point to another. By avoiding these oscillations, Ovako said it can maintain tight control over the thermal conditions in the pit furnace.
Ovako has been conducting sustainability work for many years and is said to have an 80 per cent lower carbon footprint compared to the global average.
“It is very exciting that we now have proof that it is possible to use hydrogen in heating without affecting the quality of the steel. If we can make this investment, it would have a great positive impact on the environment,” said Anders Lugnet, Group Technical Specialist, Energy & Furnace Technology at Ovako. “Our estimate is that an initial investment would save 20,000 tonnes of carbon dioxide each year, and that is just the beginning. We performed this trial in such a way that it can be reproduced at full scale in Hofors and at our other rolling mills.”