Worldwide, combustion of fossil fuels for power generation emits vast amounts of carbon dioxide (CO₂) to the atmosphere and contributes to climate change. Technology that can reduce the amount of CO₂ entering the atmosphere will be key to tackling the climate crisis.

Pacific Northwest National Laboratory (PNNL) has developed a carbon capture technology to absorb CO₂ cheaply and efficiently, at the source during pre- or post-combustion, in power plants and other flue gas emitting facilities. The technology requires 17 percent less energy to accomplish the same task as its commercial counterparts, surpassing barriers that have kept other forms of carbon capture from widespread industrial use. This translates to a 19 percent reduction in capture cost—as low as $38 per metric ton—plus the technology can be easily applied to existing capture systems.

The chemical process for extracting CO₂ from post-combustion gas involves mixing water-rich amines with CO₂-containing gas, which absorb CO₂ and are later stripped of the gas, which is then compressed and stored. But aqueous amines have limitations. Because they’re water-rich, they must be boiled at high temperatures to remove CO₂ and then cooled before they can be reused, driving costs upward.

To sidestep the challenges of water-rich solvents, PNNL has designed “water-lean” solvents that contain less than 5 percent water, reducing the energy required to release the captured carbon dioxide by boiling. This results in a more efficient, less energy intensive process. PNNL’s custom-tailored solvents are designed for maximum efficiency and reduced costs while still being simple. They are low viscosity and use molecules that align in a way that promotes internal hydrogen bonding, leaving fewer hydrogen atoms to interact with neighboring molecules. Ultimately, this lower viscosity results in a lower solvent circulation rate and reduced pumping cost.

A CO₂BOL solvent is a single component, not complex mixtures of different compounds. Unlike most commercially available, amine-based carbon capture solvents, PNNL’s technology doesn’t require co-solvents to lower viscosity. PNNL’s solvents make it simple to handle each solvent’s properties, such as boiling point, using a single dataset.

Benefits to Gas and Coal Plants and Other Manufacturing Facilities

The PNNL technology can be a drop-in replacement at existing facilities because the solvents are designed to be flexible and can be optimized for most common CO₂ capture and regeneration configurations. PNNL technology can be adapted to pre-combustion gas streams along with natural gas or any other CO₂-containing gas stream. Applications include things like CO₂-producing facilities, such as gas or coal plants interested in decarbonization, along with industrial applications like cement production plants.  Once captured, the CO₂ can be injected into the subsurface to enhance oil recovery or for long-term storage.

PNNL is further developing ways to convert captured CO₂ directly from the solvent in its CO₂-loaded state into valuable products like fuels and chemicals. Find out more about PNNL’s capture and conversion technology, which offers environmentally green solutions to efficiently convert captured carbon to fuels, such as methanol.