Solvent enables efficient gas separation, carbon capture

Researchers at Queen’s University Belfast have developed a new solvent that can separate gases efficiently and could cut global carbon emissions, according to a study published in the journal Materials Today.

Separating mixtures of gases into the pure components is critical, as it allows for the capture of carbon dioxide from fossil fuel power stations and other energy-intensive industries. Once captured, it can then be injected back into the ground.

However, the current processes that are used to do this require large amounts of energy and therefore have their own colossal carbon footprint. Indeed, around 16% of the US’s energy is used in chemical separation processes — the emissions from which are equivalent to several million cars on the road.

The process developed by Queen’s University researchers centres on a new type of solvent — porous liquid — which is much more energy efficient and is predicted to save around 30% in energy compared to the current process. As explained by Queen’s University’s Professor Stuart James, “Porous liquids, as a new concept, came about after a chance conversation between myself and Professor David Rooney, who is a chemical engineer at Queen’s.

“David pointed out that porous solids have amazing abilities to separate chemical mixtures, but being solids they cannot be pumped through pipes, which limits the ways in which they can be applied.

“Our conversation gave me the inspiration to invent a new class of materials which are porous but can also flow through pipes.”

The porous liquids developed by James and his team are able to dissolve very large amounts of gas and can selectively dissolve one gas from a gas mixture. Recent collaborative work funded by the Centre for Advanced Sustainable Energy (CASE) Competence Centre suggests that porous liquids could also be very economical and effective for the production of biomethane from biogas, which is a significant resource derived from Northern Ireland’s agricultural waste.

“This could really transform current processes,” James said. “Using porous liquids, biomethane could be produced economically from biogas and this could be added to the gas grid, as an alternative to natural gas. The good news is that in the future this could potentially be used in homes and businesses.”

In 2017, a spin-out company, Porous Liquid Technologies (PLT), was founded in a joint venture between Queen’s and the University of Liverpool to develop and commercialise porous liquids. James said, “Through PLT, we are now pioneering the use of porous liquids in various clean-fuel production processes, including biomethane, blue hydrogen and post-combustion carbon capture.

“We are now forming partnerships with established companies in these fields in order to implement our technology. For advancing the biogas work, a project is underway to demonstrate the technology on a biogas production site.”

Image credit: Queen’s University Belfast.