High Temperature Carbonation of Ca(OH)2: The Effect of Particle Surface Area and Pore Volume

The high temperature carbonation of Ca(OH) 2 forms part of a number of proposed schemes for CO 2 capture and thermal energy storage. This reaction exhibits a number of unusual features under some conditions such as Ca(OH) 2 superheating, i.e., the inhibition of the dehydration of Ca(OH) 2 . In this work the effect of the surface area and pore volume of Ca(OH) 2 particles on the conversion and kinetics of high temperature carbonation is investigated. A range of Ca(OH) 2 particles was prepared by hydration of CaO and then subjected to carbonation at high temperatures in nonisothermal thermogravimetric analysis experiments. Surprisingly, the surface area and pore volume of the sorbent, as measured by N 2 adsorption, had little effect on the conversion and kinetics of carbonation. In contrast, macroporosity associated with pores > 100 nm was postulated to have a significant effect on carbonation conversion and kinetics, possibly due to a pore-plugging mechanism.