Carbonation Kinetics of Ca(OH)₂ Under Conditions of Entrained Reactors to Capture CO₂

The use of Ca(OH)₂ as a CO₂ sorbent instead of CaO in calcium looping systems has the advantage of a much faster reaction rate of carbonation and a larger conversion degree to CaCO₃. This work investigates the carbonation kinetics of fine Ca(OH)₂ particles (<10 μm) in a range of reaction conditions (i.e., 350-650 °C and CO₂ concentrations up to 25%_v) that could be of interest for applications where a short contact time is expected between the solids and the gases (i.e., entrained bed carbonator reactors). For this purpose, experiments in a drop tube reactor with short reaction times (i.e., below 6 s) have been carried out. High carbonation conversions up to 0.7 have been measured under these conditions, supporting the viability of using entrained carbonator reactors. The experimental results have been fitted to a shirking core model, and the corresponding kinetic parameters for the carbonation reaction have been determined.