Adsorption of N2O Using Fe-13x Zeolites – a Possibility to Make a Process Intensification by Using Microwaves for the Regeneration Step

Abstract

Nitrous oxide is an effective greenhouse gas, which also greatly contributes to the depletion of the stratospheric ozone. Among the most common abatement methods, the capture of N2O by adsorption and the consequent reutilization appears as the best technique. In this work, the adsorption – regeneration cycle of N2O on 13X zeolites has been intensified by electrification of the process. More in detail, the regeneration step has been conducted in an innovative way, by employing a microwave heating. For the adsorption step, a concentrated stream consisting of 40 %vol N2O has been used, while the regeneration one was carried out using a stream of 100 %vol Ar and a power of 500 W for microwave heating. Each complete adsorption – regeneration cycle has been repeated several times, considering both wet and dry conditions for the gas mixture to be adsorbed, to prove the repeatability of the process. The results of the tests revealed that microwaves allowed to regenerate the solid adsorbent bed, by obtaining a significant reduction in the purge gas consumption and a recovery of 100 %. Therefore, employing a microwave-assisted regeneration step led to a process intensification, with respect to a conventional Temperature Swing Regeneration.