Modeling and Optimization of a Rotating Packed Bed Contactor with a Tetraamine-Appended Metal−Organic Framework for CO₂ Capture

A potential contactor technology for sorbent-based CO₂ capture is the rotating packed bed that contains separate sections for continuous adsorption and desorption. A heat exchanger can be embedded to remove heat in the adsorption section and add heat in the desorption section. In this work, we develop a two-dimensional (2D) model of a rotating packed bed for use in CO₂ capture applications. Mass and energy balances for the model are developed based on a Ljungström-type air preheater, which accounts for the counter-current axial flow of gas phases in separate sections of the bed and the rotation of a solid sorbent, which cycles between adsorption and desorption sections. The sorbent used for this analysis is the tetraamine-appended metal−organic framework Mg₂(dobpdc)(3−4− 3), chosen for its stability and affinity for CO₂ at low partial pressures, such as those from a natural gas power plant source. An optimization problem is solved that considers the trade-off between maximizing the productivity of the bed and minimizing energy consumption. Maximum productivity and minimum energy are found to be 8.53 kg/h/m³ and 3.84 MJ/kg, respectively, when these objectives are optimized independently. It is observed that the flue gas pressure and bed rotational speed are the desired operating variables to vary for model-based design of experiments to reduce uncertainty in parameter estimation, as these two variables yielded the most information content based on the Fisher information matrix.. Authors: Summits, Stephen [West Virginia Univ., Morgantown, WV (United States)] (ORCID:000900025792563X); Hughes, Ryan [National Energy Technology Lab. (NETL), Pittsburgh, PA (United States)]; Ezeobinwune, Chinyere Evangeline [West Virginia Univ., Morgantown, WV (United States)]; Laky, Daniel [University of Notre Dame, IN (United States)]; Dowling, Alexander [University of Notre Dame, IN (United States)] (ORCID:0000000193837499). DOE Contract: FE0025912. Subjects: 20 FOSSIL-FUELED POWER PLANTS; 54 ENVIRONMENTAL SCIENCES; 97 MATHEMATICS AND COMPUTING; adsorption; carbon capture; environmental pollution; inorganic carbon compounds; metal organic framework; oxides; rotating packed bed; thermodynamic properties