The new reactor captures CO2 by recreating a natural process that takes 10,000 years in the ocean in just about one minute.
Calcarea, a startup spun off from the California Institute of Technology (Caltech) and the University of Southern California (USC), has developed a new reactor to convert CO2 emissions from ship fuel combustion into seawater salt, storing CO2 for up to 100,000 years, as reported by Interesting Engineering on August 7. If widely deployed, this reactor could help the maritime industry achieve net-zero emissions by 2050.
Prototype reactor developed by Calcarea. (Photo: Calcarea)
The greatest advantage is that this reaction efficiently and rapidly mimics what the ocean has been doing. “This is a reaction that has been occurring on the planet for billions of years. If we can accelerate it, we will have a safe and long-term method for storing CO2,” said Jess Adkins, a marine chemist from Caltech and one of the founders of Calcarea.
Seawater absorbs about one-third of the CO2 emitted into the atmosphere naturally. This increases ocean acidity and causes calcium carbonate, an abundant substance in the ocean, to dissolve. “Calcium carbonate is a key component of coral skeletons, shells, and all the materials that make up a large portion of the sediment on the ocean floor,” Adkins noted. The dissolved calcium carbonate then reacts with CO2 in the water to form bicarbonate salt, which traps the CO2.
“Currently, there are about 38 trillion tons of bicarbonate in the ocean,” Adkins added. Calcarea aims to replicate this natural process by directing ship emissions into a reactor located in the ship’s hull. Inside the reactor, the emissions are mixed with seawater and limestone (a type of rock that contains calcium carbonate). As a result, the CO2 in the emissions interacts with the mixture, producing brine that captures CO2 in the form of bicarbonate salt.
Adkins indicated that a single reactor could capture about 50% of a ship’s CO2 emissions. This natural reaction takes over 10,000 years but only takes about one minute in Calcarea’s reactor. According to Adkins, the brine produced can be discharged into the ocean without harming marine life or the chemical balance of seawater.
Calcarea is also researching the addition of a filter to remove other pollutants from the emissions that may dissolve in the water, such as dust particles, unburned fuel, and other contaminants. To date, Calcarea has built two prototype reactors located in USC’s parking lot and the Port of Los Angeles. At the end of May, the startup announced a partnership with the research and development department of the international shipping company Lomar. Adkins believes this collaboration will lead to the installation of the first full-scale prototype reactor on a ship.
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