At Gulf Energy Information's Carbon Intel Forum 2023, Todd Gibbs, Marketing Manager – North and South America, Atlas Copco Gas and Process Division, delivered a presentation titled, "Blue hydrogen with carbon capture: Outlining the challenges with design due to wet CO₂."

For the most part, the technology required for carbon capture operates similarly. Gibbs began the presentation by mentioning some applications and industries that aim to decrease emissions, such as cement and steel. In this presentation, Gibbs chose to focus on blue H₂ with carbon capture.

He highlighted areas of focus that Atlas Copco examined to reduce emissions, mentioning liquified natural gas (LNG) fuel compressors for shipboard applications. According to Gibbs, when LNG is used to replace heavy fuel oils, it reduces carbon dioxide (CO₂) emissions by about 30%. Additionally, switching coal-fired power plants to gas-fired plants reduces CO₂ emissions by about 50%. This is being coupled with carbon capture.

Gibbs went on to theorize how many carbon capture projects will be needed. "I think 4,000 MMtpy of carbon capture is estimated to be needed to hit the target goals we are trying to achieve," he said.

He then touched on combustion processes—pre-combustion used in ethanol plants and post-combustion, such as coal-fired power plants in refineries and how these are associated with H₂.

"When talking about these fuel streams, like blue H₂ and other power cycles, we're looking at what is coming into the compressor out of these different streams," Gibbs said. "Whether it's coming from a refinery or another source, you see different components; quite often, it is wet."

Due to this, the compressor must be examined, ensuring that what comes out of the compressor does not negatively impact materials construction. When CO₂ reacts with water, carbonic acid is formed, from which H₂ ions dissociate, increasing the system's acidity. If H₂ is coming into the system, different materials are required to avoid embrittlement. "If you get droplets of liquid, it can erode your impellers and diffusers, causing catastrophic failures through rotating equipment," he said.

Gibbs ended the presentation by giving examples of their machinery in various projects. Shell's Polaris CCS project in Canada is utilizing Atlas Copco's high-pressure machine to decarbonize the refinery. The MTR for power station in Wyoming is working with them for membrane technology to separate the CO₂ from the exhaust gas from the coal-fired power plant.

"In places where they have a power plant that they don't want to decommission, they're trying to find ways to capture the CO₂," Gibbs said. "This machine is specifically designed to take that gas; it's a vacuum of about 5 psia that we're pulling off the stack. We are extending this stack or two compression stages into this rubber band so that the gas can be cleaned up."

Story by: Tyler Campbell, Managing Editor, H₂Tech