Limenet has industrialized the process of the geological cycle of carbon, developing a technology that can store CO₂ permanently in the oceans through calcium bicarbonates.
The raw materials used in this process are sea water, calcium carbonate and CO₂.
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Limenet accelerates the reaction between calcium carbonate and CO₂, producing calcium bicarbonate based on well-known chemical principles in scientific literature.
Based on the energy cost and the resulting carbon footprint, Limenet is testing different solutions that allow the plant to operate with electricity produced from renewable sources or thermal energy from biomass.
Step 1: Production of Slaked Lime
In the first step, limestone is processed to make it capable of capturing CO₂. Limestone (CaCO₃), one of the most abundant materials on Earth, is heated using renewable energy. This process releases CO₂ and converts the limestone into calcium oxide, also known as quicklime, a white solid. The quicklime is then mixed with water to produce slaked lime, or calcium hydroxide.
Step 2: CO₂ Capture
In the second step, CO₂ is captured from the atmosphere either by the carbonation of part of the slaked lime produced in the first step, which naturally absorbs CO₂ from the air like a sponge when exposed to it, or by using biogenic CO₂ from biomass gasification.
Step 3: Production of Calcium Bicarbonate
In the third step, both the CO₂ released from the limestone in the first step and the pure CO₂ captured in the second step react with seawater and the slaked lime that was not used to capture CO₂. The process takes place in the Limenet reactor: by mixing carbon dioxide and calcium hydroxide in sea water, calcium bicarbonate is obtained, which gives the marine environment its alkaline properties. The result is a clear solution of bicarbonates dissolved in water which has the same pH as seawater.
We have built the world’s largest plant for storing carbon dioxide in the sea in the form of calcium bicarbonate. Located in Augusta (Italy), this plant has a production capacity of 100 kg/h of CO₂ stored, a scale that exceeds by 100 times that of our pilot plant inaugurated in La Spezia (Italy) at the beginning of 2023. To learn more about Limenet’s plant, click here.
