Premiere in Spain: How hydrogen can decarbonize aluminum production

The global search for low-emission industrial processes has fueled interest in green hydrogen. So far, so familiar. The potential applications of hydrogen span a variety of sectors, but many experts say industry could benefit the most from green gas. This is true for several energy-intensive industries, and numerous projects are investigating the use of green hydrogen in the steel, glass, cement and chemical industries. One example is Salzgitter AG's SALCOS hydrogen program, which we have already presented in a topic article.

However, only a few people think of aluminum when it comes to the use of hydrogen in the process industry. Yet aluminum production is one of the most carbon-intensive industries of all: According to the German Federal Institute for Geosciences and Natural Resources (BGR), around 17 t of CO2 equivalent are produced per t of primary aluminum. By comparison, annual CO2 emissions per capita in Germany were around 7.9 t in 2017. 

The aluminum industry can therefore significantly reduce its environmental footprint by relying more on recycling and additionally using renewable hydrogen instead of natural gas. The potential is huge: according to the Federal Environment Agency, Germany produced 541,000 t of primary aluminum at a total of four locations in 2015. So let's take a closer look at the potentially emission-free process.

Cooperation with Fives

The test was conducted by Hydro Havrand, Hydro's hydrogen subsidiary, in collaboration with engineering group Fives. The scene of what the companies described as a world premiere was a foundry at Hydro's extrusion plant in Navarra, southern Spain.

"As a pioneer in decarbonizing industry, Fives has been at the forefront of hydrogen technology for decades. We are pleased to be working with Hydro on the production of carbon-free aluminum. We can draw on more than 100 years of industrial combustion experience and a wide range of state-of-the-art burners, combustion systems and digital tools," commented Stephan Paech, CEO of Fives North American Combustion Inc., on the collaboration. 

For the test, Fives first upgraded the existing TwinBed™ II combustion system - a low-NOx regenerative burner manufactured by Fives. In addition, the project partner designed and supplied the hydrogen and natural gas mixing station, as well as the controls required to operate the system. Fives also provided the computational fluid dynamics (CFD) analysis and data acquisition solution to monitor the performance of the combustion system. The machine builder's work was flanked by additional testing at its recently hydrogen-equipped laboratory in Cleveland, Ohio. 

... challenges in practice

Unfortunately, the widespread introduction of hydrogen in aluminum production still faces numerous challenges. The core problem with the green alternative is the same as with other potential applications: Production, storage and transportation of the gas need to become more competitive in order to use it on a large scale.

In addition, a robust hydrogen infrastructure needs to be built. However, this will not succeed without considerable investment and intensive cooperation between industry, politics and research. It should also be remembered that Hydro's "green aluminum" is a single test batch. Continued research and development efforts are needed to make green aluminum production more efficient.

Incidentally, hydrogen could defossilize primary aluminum production in another way: Not only the natural gas, but also the carbon anodes used in electrolysis can be replaced by hydrogen. According to some sources, this would even be significantly more efficient than the carbon variant. However, corresponding demonstration projects on an industrial scale are still pending.

The use of hydrogen offers a promising path forward, promoting a greener industry that is consistent with the goals of a low-carbon economy. Projects like that of Fives and Hydro prove that it is possible. 

To learn more about decarbonizing the metals industry, visit decarbXpo in the halls of Messe Düsseldorf from November 28-30!