REDUCING ENERGY COSTS OF INDUSTRIAL GAS SEPARATIONS USING METAL-ORGANIC FRAMEWORK BASED SOLID ADSORBENTS

 

Wendy L. Queen, Craig M. Brown, Matthew R. Hudson, Eric D. Bloch, Jeffrey R. Long

 

Due to their high internal surface areas, adjustable pore sizes, and chemical tunability, metal-organic frameworks have received considerable attention as solid adsorbents in gas storage and separation applications. Current efforts have focused particular emphasis on high density storage of various gases such as methane and hydrogen, and on the efficient removal of carbon dioxide from flue gas and natural gas deposits.  Most recently we have shown that a metal-organic framework with exposed iron(II) coordination sites features selective chemical interactions with the carbon-carbon double bond in olefins and as a result exhibits unparalleled properties for the separation of various olefin/paraffin mixtures such as ethylene/ethane. Separations of small hydrocarbons, currently performed using low temperature distillation techniques and high pressures, are among the most energy-intensive large scale separations carried out in chemical industry, a direct consequence of similarities in the size and volatility of the molecules. Therefore, tremendous energy savings could be realized if efficient separation of olefin/paraffin mixtures can be carried out at higher temperatures and atmospheric pressure.  We will present the separation properties of this new metal-organic framework in light of the gas/framework binding interactions as determined by neutron powder diffraction.