Materials and renewable energy — a supercritical combination
Sandvik’s support for supercritical water gasification is helping one customer gear up for a renewable future.
While countries across the globe are changing the way they supply and generate power, each is at a different stage of its journey. The Netherlands presents a unique case, as it must move from its reliance on an already less polluting resource.
Natural gas accounts for 40 percent of the Netherlands’ energy consumption. While still a fossil fuel, emissions from its combustion are much lower than those from coal or oil. But the Netherlands is running out of natural gas resources.
Dutch energy consumption could be boosted by replacing natural gas as a fuel source with more electricity — but this is forecasted to account for around 50 percent of the country’s energy mix. The remaining half will need to be delivered from other gases, such as green gas (methane) and hydrogen. Renewable gas has the same advantages as natural gas: it can be efficiently stored on a large scale, transported over a long distance and can be used in existing gas infrastructures.
But the majority of hydrogen currently produced is not sustainable — so how can this change?
One Sandvik customer, SCW Systems, is disrupting the creation of renewable gases, and understands the part materials technology must play.
SCW Systems develops novel technologies to convert organic waste streams into carbon neutral, or even carbon negative, energy carriers.
“SCW Systems develops novel technologies to convert organic waste streams into carbon neutral, or even carbon negative, energy carriers. The technology uses the fourth natural phase of water — the supercritical water phase — to split molecules to an almost atom level,” explains Gerard Essing, CEO of SCW Systems. “This largely untapped phase occurs when temperatures reach 375 degrees Celsius and pressure is higher than 221 bar.”
When water is in the supercritical phase, organic substances such as sewage become extremely soluble. The result of this altered property means that water becomes a solvent for organic components and is a catalyst for the conversion reactions. This results in a rapid and almost complete conversion of the energy stored in organic components into gas. From this, gas components such as hydrogen can be stored and used in the same infrastructure as existing gas supplies.
As the processes uses waste to create hydrogen, it is completely renewable and could help the Netherlands, and the rest of the world, reduce their reliance on fossil fuels.
SCW Systems is scaling up its technology with help from Gasunie New Energy, which supports renewable technologies that have proven their viability on a small scale. Together, the two companies have successfully developed, completed, and tested the first industrial reactor. Currently, the world´s first full demonstration facility is under construction and the production of the world's first industrial supercritical water gasifier has begun.
Playing our part
Following many discussions with SCW Systems, and recognizing the project’s need for advanced material selection to make its gasifiers, Sandvik began developing a solution that could meet high temperature and pressure requirements.
“During the development phase, parameters increased. SCW Systems needed to be able to raise supercritical water to 650 degrees Celsius, and to pressures up to 275 bar. Most steels wouldn’t make the cut. In addition, because the feedstock used during gasification comes from a variety of sources, advanced seamless tubes in a corrosion-resistant material was necessary”, says Dyon Hermsen, Sales Manager at Sandvik Materials Technology, who has been deeply involved in the material development process with SCW Systems.
After several years of collaborative development and testing, it was clear that material from the Sanicro® family was the solution for SCW Systems’ gasifiers. Sanicro is the Sandvik trademark for a family of nickel alloys and high-alloy austenitic stainless steels which are used in a wide range of wet-corrosive environments and high-temperature applications. This specific Sanicro material is an austenitic stainless steel with high-temperature properties. The material is characterized by its high structural stability, creep strength, and oxidation resistance and has been specifically developed for use at material temperatures up to around 700 degrees Celsius.
Sandvik specialists were able to create advanced seamless tubes that meet the challenges of this energy transition technology and support our urgency to act now
“Supercritical water gasification is an important clean energy innovation only if the advanced materials are available for the high pressure and temperature conditions. Sandvik specialists were able to create advanced seamless tubes that meet the challenges of this energy transition technology and support our urgency to act now”, says Gerard Essing.
Sandvik continues to work with SCW Systems to support the industrial production of its gasifiers, and will continually assess the success of the Sanicro material to deliver a highly durable and resistant material solution.
The future for supercritical water gasification is promising. Recently, the minister of economic affairs for the Netherlands presented a clear view on the role of green gas in the country’s sustainability goals. Setting out an ambition for 2 billion meters cubed of green gas to be produced in 2030, of which over 60 percent should be produced by supercritical water technology, demonstrates a hopeful solution to the Netherland’s natural gas shortage. Beyond the Netherlands, many countries with an existing gas infrastructure could benefit from the technology too.
Our future will certainly be powered by renewables. While the past decades of technological advancement place us on a promising path, creating advanced renewable infrastructure plays a key role in its uptake. As a result, materials experts have a huge part to play — to deliver the solutions that will build a greener world.