(276b) Evaluation of Diamine Appended Metal-Organic Frameworks for Post-Combustion CO2 Capture Using a Vpsa

The recent invention of diamine appended metal organic frameworks [1] that show unusual step-shaped isotherms have opened up the possibility to tailor-make adsorbents for post-combustion CO2 capture. By varying the metal, it was possible to position the step at various pressure levelsl. The characteristic CO2 uptake of these materials indicate a possibility to obtain larger theoretical working capacities when compared to typical classical materials such as Zeolite 13X that show classical Langmuirian-type isotherms. The performance of five different materials with step-shaped isotherms was evaluated for Vacuum swing adsorption(VSA)-based post-combustion CO2 capture from a dry flue gas. In order to evaluate the true potential of these materials, a rigorous optimization based on detailed models that take into account mass+heat transfer, cycle configuration was performed. Using Genetic algorithms the operating space was throougly scanned to obtain the Pareto curves for Purity and Recovery for five diamine-appended MOFs. The optimization results revealed that some of these materials show promise as they are able to outperform the current benchmark material, i.e., Zeolite 13X. The optimization results also demonstrated that the flue gas temperature plays a critical role in deciding which of the MOFs should be used and provide intersting heuristics for choosing operating conditions depending on the type of the MOF and the flue gas temperature. Finally, detailed optimization to reduce parastic energy showed that some of the MOF s are capable of providing lower energy consumption compared to Zeolite 13X for CO2 purity> 95% and Recovery > 90%, making them attractive materials for further study.

1.MMcDonald, Thomas M., Jarad A. Mason, Xueqian Kong, Eric D. Bloch, David Gygi, Alessandro Dani, Valentina Crocella et al. "Cooperative insertion of CO2 in diamine-appended metal-organic frameworks." Nature 519, no. 7543 (2015): 303-308.