Novel carbon storage technique ‘fastest of its kind’

In the new study, published in ACS Sustainable Chemistry & Engineering, the researchers developed a technique for ultrafast formation of carbon dioxide hydrates.

According to the researchers, the unique ice-like materials can bury carbon dioxide in the ocean, preventing it from being released into the atmosphere.

“We’re staring at a huge challenge – finding a way to safely remove gigatons of carbon from our atmosphere – and hydrates offer a universal solution for carbon storage. We need the technology to grow them rapidly and at scale,” Vaibhav Bahadur, a professor in the Walker Department of Mechanical Engineering and research lead said in a statement. “We’ve shown that we can quickly grow hydrates without using any chemicals that offset the environmental benefits of carbon capture.”

Currently, the most common carbon storage method involves injecting CO2 into underground reservoirs. This technique has the dual benefits of trapping carbon and increasing oil production.

However, the researchers said that this technique has its limitations, including CO2 leakage and migration, groundwater contamination and seismic risks associated with injection. Many parts of the world also lack suitable geologic features for reservoir injection.

Hydrates represent a ‘plan B’ for gigascale carbon storage, Bahadur said, but they could become ‘plan A’ if some of the main issues can be overcome. Until now, the process of forming these carbon-trapping hydrates has been slow and energy-intensive, holding it back as a large-scale means of carbon storage, he said.

In this new study, the researchers said they achieved a sixfold increase in the hydrate formation rate compared with previous methods, and that the speed combined with the chemical-free process makes it easier to use these hydrates for mass-scale carbon storage.

Magnesium acted as a catalyst in the technique, which eliminated the need for chemical promoters. This is aided by high flow rate bubbling of CO2 in a specific reactor configuration.

The researchers added that this technology works well with seawater, which makes it easier to implement because it does not rely on complex desalination processes to create fresh water.

“Hydrates are attractive carbon storage options since the seabed offers stable thermodynamic conditions, which protects them from decomposing,” said Bahadur. “We are essentially making carbon storage available to every country on the planet that has a coastline; this makes storage more accessible and feasible on a global scale and brings us closer to achieving a sustainable future.”

Further, the research team said that ultrafast formation of hydrates has potential applications beyond carbon sequestration, including desalination, gas separation and gas storage, offering a versatile solution for multiple industries.

The researchers and UT have filed for a pair of patents related to the technology, and the team is considering a startup to commercialise it.