The Tec-Reactor Hydroxide / Carbonate Slurry Process

The Tec-Reactor hydroxide/carbonate slurry carbon capture technology cannot be patented and several research groups are involved in further developing it including the university of Cincinnati, Ohio (Keener 2001), Los Alamos National University (Butt, Lackner et al. 1996), the university of Barcelonia (Fernandez, Segarra et al. 1999) and Arizona State University (Bearat, McKelvy et al. 2002).

The science behind the process is that depending on temperature and the partial pressure of carbon dioxide, the gas is more or less taken up by a solution of magensium hydroxide. There details of the system are still being worked out but it looks very promising especially in combination with other Gaia Engineering technologies

A recipe for making a healthy drink used by the Arabs who sell us most of the oil causing the problem serves to indicate the feasibility of this process

The colder the water (as long as it is not frozen) the more CO2 is will absorb. At say 4 degrees C the following reaction is encouraged

Mg(OH)2 + 2CO2 = > Mg(HCO3)2

At higher temperatures and with a lower partial pressure of CO2 it can easily be reversed.

The Tec-Reactor hydroxide/carbonate slurry carbon capture process is an essential part of the Gaia Engineering tececology. Inputs include fresh magnesium oxide from the Tec-Kiln and low-concentration CO2 from for example a power station.  Outputs include high-concentration CO2 and magnesium carbonate that requires rejuvenation.

Magnesium oxide from the TecEco Tek-Kiln is dissolved in water to produce magnesium hydroxide slurry.  Gas containing CO2 is bubbled through the slurry, wherein carbonation occurs, creating magnesium carbonate hydrates in solution. The slurry is then heated to cause de-carbonation whereby the CO2 previously absorbed is driven off and captured, resulting in the reformation of magnesium hydroxide that recycles through the process.

There is a limit to how many cycles can occur before contamination of the magnesium carbonate hydrate needs to be addressed.  The rate of contamination by elements like, for example, iron will depend on a number of factors including what is in the flue gasses from for example a power station. It is hoped that processing through the Tec-Kiln will remove most of this form of contamination and at least enable the reprocessed magnesium oxide to be used as inputs to make The CarbonSafe Alliance cements. Further research needs to be undertaken prior to finalising the design of the process plant to establish the number of cycles that can be run prior to decontamination via the Tec-Kiln.

[1] Keener, T. (2001). Annual Project Report - CO2 Separation and Sequestration Utilizing FGD
Scrubber By-Products, University of Cincinatti.

[2] Butt, D. P., K. S. Lackner, et al. (1996). "Kinetics of Thermal Dehydroxylation and Carbonation of Magnesium Hydroxide." Journal of the American Ceramic Society 79(7): 1892-1898.

[3] Fernandez, A. I. C., J M, M. A. Segarra, et al. (1999). "Kinetic study of carbonation of MgO slurries." Hydrometallurgy 53: 155-167.

[41] Bearat, H., M. J. McKelvy, et al. (2002). "Magnesium Hydroxide Dehydroxylation/Carbonation Reaction Processes: Implications for Carbon Dioxide Mineral Sequestration." Journal of the American Ceramic Society 85(4): 742-748.