Solubility and Growth Kinetics of Ammonium Bicarbonate in Aqueous Solution

Abstract

The formation of solid compounds in the CO2–NH3–H2O system is an important challenge in the continuous operation of ammonia-based CO2 capture processes. As the concentration of CO2 in the solvent increases along the absorption column, the formation of solids—most importantly ammonium bicarbonate (NH4HCO3)—may lead to clogging of the packing. If properly controlled, the formation of solids and their separation from the solution offer potential for improvements in the energy penalty of the capture process. This work introduces an experimental setup for seeded growth measurements in this complex system with highly volatile solutes. The crystal growth rate parameters of NH4HCO3 are determined from such experiments using a population balance equation model.