House Kurt Zenz, House Christopher H, Schrag Daniel P, Aziz Michael J
Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Environ Sci Technol. 2007 Dec 15;41(24):8464-70. doi: 10.1021/es0701816.
We describe an approach to CO2 capture and storage from the atmosphere that involves enhancing the solubility of CO2 in the ocean by a process equivalent to the natural silicate weathering reaction. HCl is electrochemically removed from the ocean and neutralized through reaction with silicate rocks. The increase in ocean alkalinity resulting from the removal of HCI causes atmospheric CO2 to dissolve into the ocean where it will be stored primarily as HCO3- without further acidifying the ocean. On timescales of hundreds of years or longer, some of the additional alkalinity will likely lead to precipitation or enhanced preservation of CaCO3, resulting in the permanent storage of the associated carbon, and the return of an equal amount of carbon to the atmosphere. Whereas the natural silicate weathering process is effected primarily by carbonic acid, the engineered process accelerates the weathering kinetics to industrial rates by replacing this weak acid with HCI. In the thermodynamic limit--and with the appropriate silicate rocks--the overall reaction is spontaneous. A range of efficiency scenarios indicates that the process should require 100-400 kJ of work per mol of CO2 captured and stored for relevant timescales. The process can be powered from stranded energy sources too remote to be useful for the direct needs of population centers. It may also be useful on a regional scale for protection of coral reefs from further ocean acidification. Application of this technology may involve neutralizing the alkaline solution that is coproduced with HCI with CO2 from a point source or from the atmosphere prior to being returned to the ocean.
我们描述了一种从大气中捕获和储存二氧化碳的方法，该方法涉及通过一个等同于天然硅酸盐风化反应的过程来提高二氧化碳在海洋中的溶解度。盐酸通过电化学方法从海洋中去除，并通过与硅酸盐岩石反应进行中和。去除盐酸导致海洋碱度增加，使得大气中的二氧化碳溶解到海洋中，在那里它将主要以碳酸氢根离子的形式储存，而不会进一步酸化海洋。在数百年或更长的时间尺度上，一些额外的碱度可能会导致碳酸钙沉淀或保存增强，从而实现相关碳的永久储存，并使等量的碳返回大气。天然硅酸盐风化过程主要由碳酸作用，而工程过程通过用盐酸替代这种弱酸，将风化动力学加速到工业速率。在热力学极限条件下——以及使用合适的硅酸盐岩石时——整个反应是自发的。一系列效率情景表明，对于相关时间尺度，该过程每捕获和储存1摩尔二氧化碳应需要100 - 400千焦的功。该过程可以由距离人口中心太远而无法直接满足其需求的闲置能源提供动力。它在区域尺度上对于保护珊瑚礁免受进一步的海洋酸化也可能有用。应用这项技术可能涉及在将与盐酸共同产生的碱性溶液返回海洋之前，用来自点源或大气的二氧化碳对其进行中和。
