Coupling Mineral Carbonation and Ocean Liming

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• 作者：P. Renforth ; T. Kruger
• 刊名：Energy & Fuels
• 出版年：2013
• 出版时间：August 15, 2013
• 年：2013
• 卷：27
• 期：8
• 页码：4199-4207
• 全文大小：356K
• 年卷期：v.27,no.8(August 15, 2013)
• ISSN：1520-5029

文摘

The process by which basic/ultrabasic silicate minerals (e.g., olivine) are reacted with CO₂ to produce solid carbonate minerals (鈥渕ineral carbonation鈥? has been suggested as a method to sequester carbon dioxide from point sources into stable carbonate minerals. Alternatively, the addition of lime (produced from calcining carbonate minerals) to the surface ocean (鈥渙cean liming鈥?, which results in an increase in ocean pH and a draw-down of atmospheric CO₂ has been proposed as a 鈥済eoengineering鈥?technology, which stores carbon as dissolved alkalinity in the surface ocean. Combining these approaches, in which the magnesium carbonate minerals produced from mineral carbonation are used as a feedstock for ocean liming (mineral carbonation-ocean liming; MC鈥揙L), may reduce the limitations of individual technologies while maximizing the benefits. Approximately 1.9 metric tons of magnesium silicate (producing 0.7 ton of magnesium oxide) are required for every net ton of CO₂ sequestered. A total of 0.7 ton of CO₂ is produced from this activity, 70% of which is high-purity (>98%) from calcining and potentially amenable for geological storage. The technology can be conceptually viewed as an alternative to direct air capture and swaps ambient CO₂ for high-purity point source CO₂. MC鈥揙L requires approximately 4.9 and 2.2 GJ of thermal and electrical energy ton^鈥? of CO₂ sequestered. MC鈥揙L has less demand for geological storage; only 0.5 ton of CO₂ needs to be injected for every ton of CO₂ removed from the atmosphere. However, manipulation of ocean chemistry in this way potentially creates an additional environmental impact (localized elevated pH or co-dissolution of trace metals) and requires additional attention.