Post-Combustion Carbon Capture Using MOFs: Materials and Process Development

Adsorption separation processes are currently being pursued extensively for carbon capture from power plant flue gas. This requires an adsorbent which exhibits a high capacity and high selectivity for CO₂. Metal organic frameworks (MOFs) are a class of materials which have shown considerable promise as novel materials for gas separation and other applications owing to their robust structure and high surface areas in comparison with existing materials for CO₂ capture. The present study, a collaborative work between SINTEF, University of Edinburgh and CERTH, is being undertaken to evaluate MOFs as potential candidates for post-combustion CO₂ capture using adsorption processes. The project includes synthesis of MOFs up to kilo-gram level quantities, characterization, formulation and evaluation of these synthesized materials by means of experiments and simulations. The major challenges in any adsorption separation process are adsorbent stability and efficiency and therefore the primary objective is to investigate and address these issues in our work.

Powdered MOF samples synthesised by SINTEF were tested at the University of Edinburgh for obtaining information on CO₂ adsorption equilibrium and kinetics. Pelletized samples up to kg levels were synthesized by SINTEF and are being tested at University of Edinburgh (UoE) for obtaining reliable equlibrium and kinetics information. Further, CERTH and UoE have developed a dynamic process simulator which shall be employed to simulate vacuum swing adsorption (VSA) configurations for CO₂ capture after validation against bench scale systems. At present, SINTEF is working on a lab scale VSA system and efforts shall be made towards validating the process simulator with the lab scale experiments.

Using the equilibrium and kinetic information in the simulator, it is possible to carry out detailed process optimization studies to identify cycle configurations with minimum energy consumption and minimum operating and capital costs. The integration of these novel adsorption cycles into the power plant configuration shall also be studied further through this collaborative work.