Air CO2 capture system based on the passive carbonation of large Ca(OH)2 structures
Direct Air Capture (DAC) requires contacting a vast flow of air with a functional surface, that has to be accommodated in a large and costly CO2 capture device (i.e. at least 0.2-0.4 m3 of reactor volume per t CO2/year). We propose here a low cost alternative that involves one or two orders of magnitude larger contactor volumes, but relying only on the passive CO2 carbonation of purpose-built porous structures of Ca(OH)2. Such low cost materials can be manufactured from natural limestone and/or recycled carbonated structures, by using oxy-calcination technologies, and then simply piled up and exposed to ambient air. After examining the rate controlling factors of the carbonation reaction, we adopt a particular structural element in the form of sintered Ca(OH)2 plates of 2x2 m2, cm thickness and 0.5 porosity, that can be fully carbonate in about 6 months. Since the components of the full process to manufacture or regenerate these elements are relatively well known, the cost uncertainties and contingency factors are much lower than for other DAC systems. A CO2 avoided cost below 170 $/tCO2 can be estimated when the cost incurred from the land use occupied by the Ca(OH)2 structures is neglected.
| Main Authors: | , , |
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| Other Authors: | |
| Format: | artículo biblioteca |
| Language: | English |
| Published: |
Royal Society of Chemistry (UK)
2020-02-17
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| Online Access: | http://hdl.handle.net/10261/201432 |
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