Adsorption and diffusion of gases in barium exchanged small pore titanium silicate

Abstract

<P>UPGRADING NATURAL GAS BY SEPARATING NITROGEN FROM METHANE IS A PROBLEM OF SIGNIFICANT COMMERCIAL IMPORTANCE. THE CURRENTLY USED CRYOGENIC PROCESS IS VERY ENERGY INTENSIVE AND EXPENSIVE TO OPERATE. ETS-4 AND ITS ION EXCHANGED VARIANTS HAVE CONTRACTIBLE MICROPORE SIZE THAT OPENS NEW OPPORTUNITIES FOR THE SEPARATION OF SMALL GASES OF COMPARABLE MOLECULAR SIZE. IN THIS STUDY, BARIUM-EXCHANGED ETS-4, BA-ETS-4, HAS BEEN DEVELOPED AS A NITROGEN-SELECTIVE ADSORBENT, WHICH CAN PROVIDE A POTENTIAL ALTERNATIVE LOW-COST PROCESS FOR UPGRADING NATURAL GAS. THE MATERIAL WAS SYNTHESIZED AND CHARACTERIZED FOR ITS CRYSTAL STRUCTURE AND MORPHOLOGY, AND THERMAL BEHAVIOUR. THE PORE CONTRACTION WAS OPTIMIZED BY CONTROLLED DEHYDRATION TO MAXIMIZE THE SELECTIVITY OF NITROGEN OVER METHANE. COMPLETELY EXCHANGED BA-ETS-4 DEHYDRATED AT 400 DEG.C SHOWED THE HIGHEST SELECTIVITY OF ~ 201, WHICH FAR EXCEEDS THE VALUE IN THE LITERATURE. DETAILED EQUILIBRIUM AND KINETIC MEASUREMENTS WERE CARRIED OUT AND THE RESULTS