Najat Aya: part of the climate-neutral steel production team

_{^{01.09.2020 I Carolin Mielke}}

It’s an ambitious goal: thyssenkrupp Steel aims to be completely climate-neutral by 2045. For energy-intensive steel production in particular this means nothing less than a radical change in production processes. One engineer working on the future of steel production is Najat Aya.

thyssenkrupp is working flat out to achieve the goal of climate neutrality. For steel production this is a truly Herculean task. The burning of carbon in steel production generates large amounts of carbon dioxide: In conventional blast furnaces, carbon is burned to reduce the oxygen contained in the iron ore raw material. The process produces not only pig iron, which is then further processed into steel, but also CO₂.

Climate-neutral steel production by 2045

thyssenkrupp is pursuing two main approaches to reducing these unwanted CO₂ emissions: The “Carbon2Chem” project aims to convert steel mill emissions, including the CO₂ they contain, into valuable chemicals for further use. The technology is expected to be available on a commercial scale as early as 2025.

The second approach relies on hydrogen, as Najat Aya explains: “In order to avoid CO₂ emissions, the plan is to use hydrogen as a reducing agent in the blast furnace instead of carbon. The advantage is that using hydrogen produces water vapor, whereas with coal you’re producing CO₂”. It sounds simple, but of course it’s not. The processes are complex: “Using hydrogen in the blast furnace also changes the proportion of hydrogen in the blast furnace gas, which is a by-product of the blast furnace process,” reveals Najat. “We use this blast furnace gas and will continue to do so, so it’s important to know how the changed composition affects our processes.”

Internship, dissertation, trainee program

Najat Aya should know. A graduate of Duisburg-Essen university, Najat is a trainee in the energy management and process engineering/process control department at thyssenkrupp Steel Europe AG researching the use of hydrogen in steel production. The 26-year-old joined thyssenkrupp Steel Europe in Duisburg in April 2017, initially on a three-month internship as part of the seventh and final semester of her mechanical engineering course, in which she specialized in energy and process engineering.

“Three months turned into three years,” laughs Najat. “After the internship, thyssenkrupp offered me the opportunity to work with them writing my bachelor’s dissertation.” Afterwards she took a master’s degree, which thyssenkrupp supported with a scholarship. Najat also wrote her master’s thesis at thyssenkrupp. In it, she dealt intensively with cowpers for the first time. Cowpers are hot blast stoves which are used in steel production to supply a blast of oxygen at over 1,000°C for combustion in the blast furnaces.

Najat began her traineeship at thyssenkrupp Steel Europe in the month she graduated. Her experience with cowpers quickly came in handy. “To bring the cowpers to the desired temperature, several aspects have to be taken into account, for example, the tendency of the cowpers to pulsate,” reveals the young engineer. “By studying the combustion process inside the cowpers and making a mixed gas analysis, we discovered that additional hydrogen should not be fed into the cowpers. The blast furnace gas with the higher hydrogen content is therefore supplied to our power plants. The cowpers, on the other hand, are supplied with gas from other blast furnaces.”

“We’re on the right track”

Najat has no doubt that steel production will be CO₂-neutral by 2045. “We have to consider many aspects in order for steel to become climate-neutral,” she concedes, “but we’re definitely on the right track.”

When Najat talks about her job, she often uses the word “we”. As a team player, she appreciates the value of effective teamwork: “Once you become part of a team, you quickly realize that a smart team is always better than a single genius. Together, not only can you achieve much more, you get there faster.”

There’s no such thing as a “typical” working day for Najat. “Our work is incredibly varied. For example, we support our hot-dip coating lines. When it comes to control or furnace optimization models, our team comes into play. We also provide support for many process engineering tasks. We can also assist when it comes to fluid dynamics analyses. Among other things, we carry out numerical flow simulations in order to better understand processes within the production units and optimize the various processes.”

A “cool job”

Even as a child Najat knew she would be an engineer one day. “I didn’t have a clear idea of what branch of engineering I would choose or what industry I would work in. But I knew that I would have a cool job and I was right.”