How Does the Ocean Carbon Capture System Work?
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Zhonglin International Group Date：05-29 785 Belong to：Industry Related
In order to achieve carbon neutrality goals, in addition to reducing carbon emissions, we also need to use negative carbon technologies such as carbon sequestration, carbon capture, and storage to reduce the carbon content in the air.
Direct air capture (DAC) is a negative carbon technology that we have introduced extensively before.
The traditional direct air capture technology can be divided into solid DAC and liquid DAC, which directly capture carbon dioxide from the ambient air through chemical treatment. This technology faces challenges such as low concentration of carbon dioxide in the air, high energy consumption, and high cost.
For this reason, some fossil fuel giants and large technology companies are supporting an innovative carbon capture - extracting carbon dioxide from the ocean as a way to address climate change.
This emerging technology, known as direct ocean capture (DOC), was proposed by Captura, a carbon removal company established at the California Institute of Technology.
The company plans to extract carbon dioxide from seawater and release purified water back into the ocean, using only renewable electricity and seawater as inputs to minimize environmental impact. Due to the lack of specially built air contactors, absorbers, and by-products, Captura's solution can achieve large-scale carbon removal at a lower cost. According to reports, this DOC technology developed by the California Institute of Technology can extract one billion tons of carbon from the ocean in the future.
This company won the XPRIZE carbon clearance competition in April 2022, sponsored by Tesla founder Elon Musk, and received a prize of $1 million. In December 2022, Captura entered Frontier's $11 million second round of decarbonization technology procurement list. In January of this year, Captura received a Series A financing of $12 million led by Equinor Ventures and co invested by well-known investment institutions such as Saudi Aramco Venture Capital, California Institute of Technology Seed Fund, and Future Planet Capital.
1. Working principle of marine carbon capture system
The Captura marine carbon capture system will achieve direct ocean capture through the company's patented electrodialysis process, using only renewable electricity and seawater as inputs to generate a pure CO2 stream that can be stored or reused for the production of other low-carbon materials or products to mitigate the adverse effects of climate change.
The characteristic of Captura technology is that seawater flows through factories, is then processed to remove its carbon dioxide content, and finally returns to the ocean. This decarbonization water level is located at the top of the ocean and then reacts with the atmosphere to absorb the same amount of carbon dioxide. The ocean absorbs 30% of the world's carbon dioxide emissions, and Captura utilizes the natural ability of the ocean to absorb carbon dioxide from the atmosphere. The carbon dioxide absorption capacity of the ocean, as well as Captura's technology, relies on a principle called Henry's Law. Due to the equilibrium effect, CO2 naturally flows from higher concentration points to lower concentration points, which is similar to the principle of diluting beverages after opening beer or soda cans.
The process first sucks the filtered seawater into the facility, where less than 1% of the water is transferred and pretreated to purify the seawater into pure saltwater. Subsequently, this saltwater was treated in Captura's proprietary electrodialysis technology, which used renewable electricity to decompose salt and water into acids and bases through dissociation and electrodialysis.
Then, this acid is added to seawater, triggering a chemical reaction to extract carbon dioxide from the water. Accelerate the process using gas-liquid contactors and vacuum pumps to generate a reusable or isolated purified carbon dioxide flow. The acidic and decarbonized seawater left in the system is neutralized by adding alkaline substances, and the neutralized seawater flow can return to the ocean to recapture carbon dioxide in the atmosphere.
In summary, Captura's technology fully utilizes renewable electricity and seawater to remove carbon dioxide from the atmosphere without any by-products or absorbers.
2. Future Development
Since August 2022, Captura's first direct ocean capture technology pilot has been conducted at the Kerckhoff Marine Laboratory at the California Institute of Technology in Newport Beach, California. After a validated end-to-end demonstration at the factory in Pasadena, the technology has proven to operate in continuous seawater. The first pilot project can remove 1 ton of CO2 from the atmosphere every year, equipped with sensors and instruments to continuously monitor performance.
After the successful pilot experiment, Captura established a partnership with AltaSea at the Port of Los Angeles in May this year to further promote marine climate solutions. AltaSea's 35 acre Blue Economic Park will be the location of Captura's second direct ocean capture pilot system, which can capture 100 tons of carbon dioxide from the ocean annually.
This latest system, funded by SoCalGas, has been 100 times larger than Captura's first pilot and has been running end-to-end in the Pasadena laboratory. Captura plans to transfer the system to AltaSea in the coming months to begin sea trials. In order to advance this technology, Captura will also conduct ocean modeling and technology development to further validate, expand, and strengthen its innovative processes.
Captura CEO Steve Oldham said, "Through our pilot program, Captura's technology is rapidly evolving towards large-scale commercial deployment. Now, our collaboration with AltaSea means we can further accelerate our technology and monitor how our systems interact with the ocean."
The two companies will continue to uate the achievements of the new system, including the impact of DOC on marine ecosystems and its potential to help alleviate ocean acidification.
