Alleima Sanicro® 31 HT: the right alloy for the right energy at the right time Skip to content

The urgency of global warming has seen hydrogen emerge as a leading driver of sustainable alternatives to fossil fuels.

Little wonder, for hydrogen, is a source of clean energy, an efficient means of energy storage for renewables such as wind and solar power, a fuel for sustainable transport, a way to generate clean electricity and heating, and a cleaner alternative for industrial processes.

For reasons of efficiency and lower costs, 90-95% of global hydrogen production occurs through steam methane reforming, where methane from natural gas is heated in a Reformer to produce pure hydrogen, high temperatures around 800-900 degrees Celsius can be reached.

The reactors themselves consist of multiple vertical catalyst tubes that feed down into horizontal tubing known as a ‘pigtail’ due to its geometry. The pigtail is one of the most critical pieces of the reformer as it carries the reformer gas from the catalyst tube to the collection manifold while discharging the mechanical stress and displacement experienced by the reformer unit system due to the thermal expansion that comes from the reforming process.

Why Sanicro® 31HT is ideal for hydrogen production?

“Sanicro® 31HT from Alleima is an austenitic nickel-iron-chromium alloy with good structural stability at temperatures as high as 1,100 degrees Celsius,” says Eduardo Perea, Senior Product Manager, Alleima Tube division, EMEA.

Eduardo Perea, Senior Product Manager“The usual reasons for failure of the tubing materials are creep fatigue (sagging and deformation) and carburization from the surrounding environments in the tube. But Sanicro® 31HT is a stainless-steel alloy that has very good resistance to oxidation, combustion gases, carburization, and nitrogen environments. The alloy also offers good weldability and high creep strength.”

_{High-temperature challenge - full presentation.} (PDF, 537 kB)

Eduardo Perea is a passionate and convincing advocate of Sanicro® 31HT and even uses cooking metaphors to explain the secret of its success. Quite simply, he says, the alloy is a significant improvement on an established ‘recipe’, in this case, the industry-standard Alloy 800 HT, which was introduced in 1989.

“Our alloy is super-resistant to the different environments in the steam methane reforming process, including carburization, and creep strength. Getting the balance right in the chemical composition is extremely important to get the optimum recipe, the tubes are produced in our fully integrated Production Unit in Sandviken, Sweden.

“If you compare our recipe with others in the market, you’re ‘eating’ different soups from the same recipe and ours not only tastes better but keep your stomach full for a longer time! We offer more superior, stronger versions of the alloy” he says.

An Alleima alloy that’s “good news for our world”

Eduardo Perea adds that Sanicro® 31HT has established a leading position in the sustainable energy market. “Apart from its suitability for the machines used in the steam methane reform process for hydrogen production, the alloy is also becoming a key element in solar energy production,” he says.

Here, the alloy’s temperature, corrosion resistance, and strength are crucial for high-performance production of pure polysilicon, which is an essential raw material for solar energy, which is growing at an exponential rate. Furnace tubes and muffle tubes used in industrial applications also benefit from Sanicro® 31HT’s outstanding properties and versatility, with its weldability to other materials a big advantage.

So, as the world continues to explore hydrogen fuel cells for passenger cars, as a source and enabler of renewable energy and ways to make industrial processes cleaner, more efficient, and cost-effective, Eduardo Perea concludes that Sanicro® 31HT has a hugely significant role to play.

“Quite simply it’s a catalyst for helping to create more sustainable processes and energy alternatives, which is good news for our world,” he says.