Pilot tests and rate-based modelling of CO₂ capture in cement plants using an aqueous ammonia solution

A rate-based model for the absorption of CO₂ with aqueous ammonia solutions has been developed on the grounds of new CO₂ absorption experiments performed at pilot plant scale. Tests have been performed with synthetic flue gases reproducing cement plant conditions. A thorough design of experiments has been carried out with the aim of studying the influence of several variables on the CO₂ capture performance and obtaining a reliable model in a broad experimental space. The newly developed rate-based model makes use of a thermodynamic framework that predicts reliably the formation of solids in the CO₂-NH₃-H₂O system in order to avoid operating conditions that lead to clogging of the absorber.