Separation of Hexane Isomers and light Olefin Paraffin Mixtures using Metal Organic Frameworks as Adsorbents

Abstract

Adsorption-based separation of hydrocarbons have been investigated widely by newlineresearchers across the globe employing variety of adsorbent materials including newlinezeolites and metaland#8722;organic frameworks (MOFs). However, the quest for yet an newlineefficient adsorbent is still of prime importance. In the present thesis, investigations newlineon separation of hexane isomers and olefin/paraffin mixtures in MOFs are newlinepresented. In Chapter 2, Molecular modelling and computational science tools newlinewere employed to select a number of MOFs from a large pool of structures to newlineinvestigate and assess their kinetic and adsorption-based separation newlineperformances in separating hexane isomers. The self-diffusivities of all singlecomponent newlineisomers were obtained from molecular dynamics simulations at infinite newlinedilution and at a loading of 4 molecules/unit cell and at several temperatures. The newlineself-diffusivities of the binary mixtures of the hexane isomers were also computed newlineto obtain the kinetic separation metrics. Further, the performances of these chosen newlineMOFs were assessed in separating the linear hexane from the two dibranched newlineones as well as the dibranched ones from each other. MOF IYIHUU shows the newlinehighest membrane selectivity of the dibranched hexanes over the linear one at 433 newlineK and at a pressure of 10 bar. newlineIn Chapter 3, MOF structures from CoRE MOF database were ranked on the basis newlineof various performance metrics, namely, adsorption selectivity, working capacity, newlineand regenerability. Six binary mixtures, one three-component equimolar mixture, newlineand one five-component equimolar mixture of hexane isomers were investigated newlineat temperatures of 383, 433, 483, and 533 K. The rankings of MOFs were also newlinecarried out at different temperatures close to the typical isomerization reactor newlinetemperature. It was observed that the orders of the rankings at different newlinev newlinetemperatures are different. MOFs BIMDOR and WAMRIN01 perform the best with newlinehigh adsorption selectivity for all the mixtures. It was observed that the MOFs with newlinevery high adsorption selectivity do not have high w