December 6, 2023

Captura Corporation, a subsidiary of Caltech, has a revolutionary plan to eliminate carbon emissions by building aquatic purification facilities in the sea. The company intends to extract carbon dioxide from seawater and release the purified water back into the ocean, using only renewable electricity and seawater as input to minimize environmental impact.

Carbon cleanup will be achieved through the company’s patented electrodialysis process, known as Direct Ocean Capture (DOC). DOCs produce a stream of pure CO2 that can be stored or reused to produce other low-carbon materials or products to mitigate the adverse effects of climate change. The company aims to achieve large-scale carbon removal at a lower cost than existing methods.

The DOC technology developed at Caltech is reportedly capable of extracting gigatonnes of carbon from the ocean. The process begins by bringing filtered seawater to a facility where acid is produced using electrodialysis technology.

This acid is then added to seawater, triggering a chemical reaction that extracts carbon dioxide from the water. The process is accelerated using gas-liquid contactors and vacuum pumps, resulting in a stream of purified carbon dioxide that can be reused or sequestered.

Captura's Direct Ocean Capture technical infographic
Captura’s Direct Ocean Capture technical infographic

Captura Corporation

“Less than 1 percent of the water is diverted and pretreated, purifying the seawater into pure brine,” Captura said. “This brine is then treated in Captura’s proprietary electrodialysis technology. Through dissociation, electrodialysis uses Renewable electricity splits salt and water into acids and bases.”

The process of neutralizing the seawater flow is done by adding an alkaline base. This helps absorb carbon dioxide from the atmosphere and then returns the decarbonized water to the ocean. According to Captura, this water can react with the atmosphere to absorb an equivalent amount of carbon dioxide. Once filtered, seawater has the extraordinary ability to reabsorb an equivalent amount of carbon dioxide from the atmosphere that was originally removed. This unique capability makes it an effective tool for mitigating the effects of climate change.

“This decarburized water sits at the top of the ocean and then reacts with the atmosphere to absorb an equivalent amount of carbon dioxide,” Captura said.

In 2022, Captura will establish its first ocean test facility in Newport Beach, California as a stand-alone unit. The company uses a continuous flow of seawater to measure system performance and make necessary improvements.

Captura's 100-ton direct ocean capture pilot system at its Pasadena lab
Captura’s 100-ton direct ocean capture pilot system at its Pasadena lab

Captura Corporation

Following the successful pilot test, Captura (in partnership with AltaSea in the Port of Los Angeles) plans to build its second direct ocean capture system, each capable of removing 100 tons (90.7 tons) of CO2-year from the ocean. To advance this technology, Captura will conduct ocean modeling and technology development with the goal of further validating, scaling and enhancing its innovation process.

“Through our pilot program, Captura’s technology is rapidly progressing towards large-scale commercial deployment,” said Captura CEO Steve Oldham. “Now, our partnership with AltaSea means we can Further accelerating our technology and monitoring how our systems interact with the ocean, we couldn’t think of a better partner to help us take our advancements to the next level. Besides the support from SoCalGas, this is truly a California company A great example of working together to take a leading role in the fight against climate change.”

source: Captura Corporation