New filtration material could make petroleum refining cheaper, more efficient

May 23, 2013
This view of the molecular structure of the MOF shows the triangular channels that run through the material. The walls of these channels trap the lower-octane components of gas while allowing the higher-octane molecules to pass through, potentially providing a more efficient and cost effective way to refine high-octane gasoline. Credit: Science

A newly synthesized material might provide a dramatically improved method for separating the highest-octane components of gasoline. Measurements at the National Institute of Standards and Technology (NIST) have clarified why. The research team, which included scientists from NIST and several other universities, has published its findings in the journal Science.

Created in the laboratory of Jeffrey Long, professor of chemistry at the University of California, Berkeley, the material is a metal-organic framework, or MOF, which can be imagined as a sponge with microscopic holes. The innumerable interior walls of the MOF form triangular channels that selectively trap only the lower-octane components based on their shape, separating them easily from the higher-octane molecules in a way that could prove far less expensive than the industry's current method. The Long laboratory and UC Berkeley have applied for a patent on the MOF, which is known by its chemical formula, Fe2(bdp)3.

High-octane gasolines, the ultra or premium blends at fueling stations, are more expensive than regular unleaded gasoline due to the difficulty of separating out the right type of molecules from petroleum. Petroleum includes several slightly different versions of the same molecule that have identical molecular formulae but varying shapes—called . Creating premium fuel requires a refinery to boil the mixture at precise temperatures to separate the isomers with the most . The trouble is, four of these isomers—two of which are high octane, the other two far lower—have only slightly different boiling points, making the overall process both challenging and costly.

The new MOF, however, could allow to sidestep this problem by essentially trapping the lowest-octane isomers while letting the others pass through. The lowest-octane isomers are more linear and can nestle closer to the MOF walls, so when a mixture of isomers passes through the MOF, the less desired isomers stick to its surface—somewhat akin to the way a wet piece of paper sticks.

Matthew Hudson and his colleagues at the NIST Center for Neutron Research (NCNR) used neutron powder diffraction, a technique for determining molecular structure, to explore why the MOF has the right shape to selectively separate the isomers. Their research was essential to validate the team's model of how the MOF adsorbs the low-octane isomers.

"It's easier to separate the isomers with higher octane ratings this way rather than with the standard method, making it more efficient," says Hudson, a postdoctoral fellow at the NCNR. "And based on the lower temperatures needed, it's also far less energy-intensive, meaning it should be less expensive." Hudson says that while industrial scientists will need to work out how to apply the discovery in refineries, the new MOF appears to be robust enough in harsh conditions to be used repeatedly a great many times, potentially reducing the necessary investment by a petroleum company.

Explore further: A new dimension for 3-D protein structures

More information: Z.R. Herm, B.M. Wiers, J.A. Mason, J.M. van Baten, M.R. Hudson, P. Zajdel, C.M. Brown, N. Masciocchi, R. Krishna and J.R. Long. Separation of hexane isomers in a metal-organic framework with triangular channels. Science, May 24, 2013. DOI: 10.1126/science.12334071

Related Stories

Carbon sponge could soak up coal emissions

Feb 12, 2013

Emissions from coal power stations could be drastically reduced by a new, energy-efficient material that adsorbs large amounts of carbon dioxide, then releases it when exposed to sunlight.

A new dimension for 3-D protein structures

May 13, 2013

(Phys.org) —3D structures of biological molecules like proteins directly affect the way they behave in our bodies. EPFL scientists have developed a new infrared-UV laser method to more accurately determine ...

Recommended for you

A greener source of polyester—cork trees

6 hours ago

On the scale of earth-friendly materials, you'd be hard pressed to find two that are farther apart than polyester (not at all) and cork (very). In an unexpected twist, however, scientists are figuring out ...

A beautiful, peculiar molecule

9 hours ago

"Carbon is peculiar," said Nobel laureate Sir Harold Kroto. "More peculiar than you think." He was speaking to a standing-room-only audience that filled the Raytheon Amphitheater on Monday afternoon for the ...

Metals go from strength to strength

Apr 15, 2014

To the human hand, metal feels hard, but at the nanoscale it is surprisingly malleable. Push a lump of metal with brute force through a right-angle mould or die, and while it might look much the same to the ...

User comments : 0

More news stories

Breakthrough points to new drugs from nature

Researchers at Griffith University's Eskitis Institute have developed a new technique for discovering natural compounds which could form the basis of novel therapeutic drugs.

A greener source of polyester—cork trees

On the scale of earth-friendly materials, you'd be hard pressed to find two that are farther apart than polyester (not at all) and cork (very). In an unexpected twist, however, scientists are figuring out ...

A beautiful, peculiar molecule

"Carbon is peculiar," said Nobel laureate Sir Harold Kroto. "More peculiar than you think." He was speaking to a standing-room-only audience that filled the Raytheon Amphitheater on Monday afternoon for the ...

Down's chromosome cause genome-wide disruption

The extra copy of Chromosome 21 that causes Down's syndrome throws a spanner into the workings of all the other chromosomes as well, said a study published Wednesday that surprised its authors.

IBM posts lower 1Q earnings amid hardware slump

IBM's first-quarter earnings fell and revenue came in below Wall Street's expectations amid an ongoing decline in its hardware business, one that was exasperated by weaker demand in China and emerging markets.