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Researchers identify promising materials for next-generation sour gas sweetening

Mansi Shah, a fourth-year graduate student in Chemical Engineering & Materials Science (CEMS), and her advisers, professors Michael Tsapatsis from CEMS and Ilja Siepmann from the Department of Chemistry, have identified promising zeolite structures that will be instrumental in the design of next-generation gas sweetening technologies.

Gas sweetening refers to removal of hydrogen sulfide and carbon dioxide from raw natural gas mixtures. Traditionally, the natural gas industry has employed a highly energy-intensive amine-based separation to remove these toxic and corrosive impurities but this process is not economically feasible for highly sour gas reservoirs. Using large-scale supercomputers and a hierarchical screening approach, this team of researchers investigated adsorption in zeolites as an alternative separation process. These crystalline porous materials can act as sponges to selectively and efficiently adsorb hydrogen sulfide from multi-component gas mixtures. Monte Carlo simulations were used to study the adsorption of binary H2S/CH4 and H2S/C2H6 mixtures in 386 zeolite structures over wide ranges of composition, temperature, and pressure to select 16 zeolite structures for assessment of the adsorption of four- and five-component mixtures at wellhead conditions. This predictive modeling study identified zeolite structures that enable sweeting of highly sour natural gas in a more cost-effective and sustainable fashion.

This research is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences under Award DE-FG02-12ER16362 and used resources of the Argonne Leadership Computing Facility at Argonne National Laboratory. Additional computer resources were provided by the Minnesota Supercomputing Institute. The University of Minnesota filed a provisional patent application related to this research and hopes to license the technology in the near future. A manuscript describing this research has appeared online in Angewandte Chemie International Edition [10.1002/anie.201600612] and will also featured as a frontispiece in a future issue.