Greene Tweed develops protocol, FFKM to aid carbon capture

LANSDALE, Pa.—Greene Tweed & Co. has seen carbon capture technologies become more prevalent methods to removing carbon dioxide from the environment.

And amine-based solvents are one typical form of technology used to capture CO2.

"The increased use of amines in technologies like carbon capture are driving increased focus on chemical resistance of materials used to seal process equipment like pumps," Seema Gangatirkar, product manager for Greene Tweed's industrial Chemraz business, told Rubber News in an email interview.

To help service this trend, the Lansdale-based producer of seals, high-end elastomers, engineered components, composites and thermoplastics has developed a protocol to test its perfluoroleastomer materials for resistance to a variety of fluids, including amines.

Greene Tweed also recently used this protocol in the development of Chemraz 541, one of its newest compounds for the oil and gas industry. Because sustainability is a core focus for GT and its customers, it was able to identify this as a need for its customers in the sector.

"This includes investing in the exploration of technologies like carbon capture, which uses amine solvents to separate CO2—similar to how H2S is removed from natural gas in a process called gas sweetening," Gangatirkar said. "We have experience providing seals for gas sweetening, which allowed us to identify a critical market need: improving resistance to amines."

She added that GT developed the protocol to test for chemical resistance because it wanted to give its customers a benchmark on how a material will fare in a particular type of fluid.

"Depending on the application or market, we adjust the test to give customers data that informs them to how a particular material will perform in their unique applications," the Greene Tweed product manager said. "For example, in oil and gas applications, we generally evaluate how our materials perform in representative fluids per the ASTM D471 methodology, and that would include hydrocarbons, water, steam and acids."

Given the use of amines in gas sweetening as well as carbon capture technologies, the firm added an aggressive amine—diglycolamine—to its testing protocol. That helped GT establish a baseline for how its Chemraz-brand perfluoroleastomers would perform—not only in amines but also at elevated temperatures, which can impact seal compatibility.

"Our application engineers then use this data to make recommendations on what material will provide the optimal sealing solution based on the process conditions," she said.

Greene Tweed was driven by customer insights to begin compound development, and it maintained two-way communication with customers during the development. Because of the requirement to establish chemical resistance to amines, the firm focused on a new proprietary formulation in its Chemraz perfluoroleastomer line, as the FFKMs provide the highest level of chemical resistance among all elastomers.

"Once we identified the type of elastomer needed for these applications, we began a rigorous and careful development process that also incorporated feedback from our customers to help us generate the right data set," Gangatirkar said. "The development process of Chemraz 541 was no different."

Feedback from customers made it clear that increased chemical resistance to amines was critical for enabling certain technologies like gas sweetening and carbon capture.

"We have a comprehensive research and development program to support the next generation of technology and products, and offering a new compound specifically developed to provide improved chemical resistance in aggressive fluids was a natural fit for us," she said.

Resistance to amines is a key data point in helping to increase carbon capture, according to the GT product manager. Greene Tweed considers a material to have excellent compatibility with a fluid—both in static and dynamic service—if the material's volume changes when soaked in the fluid measures less than 10 percent.

After a one-week soak in diglycolamine at 302°F /150°C, Chemraz 541 post-soak measurements registered the volume change at 6 percent, making it a reliable sealing choice in amines, especially when compared to other materials with similar properties.

"Given how aggressive a fluid like diglycolamine is, and at the elevated temperature at which it was tested, it gave us confidence that we had reached our goal of improving chemical resistance," Gangatirkar said.

So far, Greene Tweed has received positive feedback on how seals made of Chemraz 541 have performed in critical applications, especially where chemical resistance has been a key criterion for a seal.

GT engineered the Chemraz 541 perfluoroleastomer as a universal purpose compound suitable for a wide range of industries, including chemical processing, life sciences, oil and gas and semiconductors.