469778 High-Purity Oxygen Production Using Silver Exchanged Titanosilicates (Ag-ETS-10)

Wednesday, November 16, 2016: 12:30 PM
Cyril Magnin II (Parc 55 San Francisco)
Sayed Alireza Hosseinzadeh Hejazi, Arvind Rajendran and Steven Kuznicki, Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada

High-purity (>99%) oxygen is required in many medical and industrial applications such as pharmaceutical and aerospace applications. Producing oxygen with purity of higher than 95% from atmospheric air (78% N2, 21% O2 and 1% Ar) is challenging because of similar physical properties of oxygen and argon such as the molecule size and the boiling point. Adsorption separation techniques are economically preferable to conventional cryogenic distillation of O2/Ar for small and medium scale applications but a limited number of commercial adsorbents are selective toward O2/Ar. Recent multi-component breakthrough experiments in our laboratory have shown that silver exchanged titanosilicates (Ag-ETS-10) have the potential to separate these gases based on their thermodynamic affinities. This opens up the possibility of developing processes for high purity O2 separations.

In this work, adsorption isotherms of N2, O2, and Ar on Ag-ETS-10 extrudates have been measured utilizing a volumetric apparatus and described using a Langmuir isotherm. In order to validate the large-scale performance of the adsorbent, single, binary, and ternary breakthrough profiles were obtained using a laboratory scale dynamic column breakthrough apparatus. These experiments have been described by discretising mass and energy balances using the finite volume technique. The model could predict the experimental profiles to a high level of precision. Various Pressure/Vacuum swing adsorption (P/VSA) cycle configurations including simple Skarstrom cycle and more complicated VSA cycles were simulated using mathematical models to maximize O2 purity and recovery. Both 95%/5% O2/Ar and dry air feed were considered in the simulations and a rigorous multi-objective optimization was conducted to maximize O2 purity and recovery which indicated the ability of Ag-ETS-10 to separate ultra-high purity O2 with good recovery. Effect of different operating parameters on O2 purity and recovery and rigorous multi-objective optimization results to maximize oxygen productivity and minimize energy consumption of the P/VSA cycles (while meeting the purity-recovery constraint) were studied. The comparison of the simulation results with single-column experiments will be presented.

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