Design and optimization of VSA process for post combustion carbon capture using NbOFFiVE-1-Ni

Abstract

Finding an efficient way to capture carbon dioxide in the exhaust gas is becoming ever more and more important. In this work, NbOFFIVE-1-Ni, a metal–organic framework (MOF) with moisture resistant, is synthesized in kg scale for designing and optimizing vacuum swing adsorption (VSA) process. The equilibrium adsorption isotherms and dynamic breakthrough experiment results showed that, adsorption amount at 0.1 bar can reach up to 2.0 mmol/g and the cyclic dynamic adsorption amount can be regenerated 85 % at 303 K and vacuum condition. The CO₂/N₂ separation performance is also excellent where the breakthrough time of CO₂ is more than 51 times longer than N₂, consisting with the high IAST selectivity, over 2200. On the basis of the proper isosteric heats of adsorption (Qst) value (45kJ•mol⁻¹) and regeneration condition, two-bed and three-bed five step VSA processes were designed for further evaluating the influence on purity, recovery and adsorbent efficiency caused by the cyclic schedule and parameters in simulation process. The optimized results showed that, productivity and working capacity of NbOFFIVE-1-Ni are increased 65 % (180 L/L/h to 298 L/L/h) and 41 % (34 g/L to 48 g/L) with the purity and recovery over 95 vol% and 90 % which could completely meet the requests of DOE NETL. Office. In all, NbOFFIVE-1-Ni is capable to carbon capture excellently, and the appropriate design of cycle schedules and parameters can greatly improve the efficiency of adsorbents in the VSA process for post combustion carbon capture.