Page 58 - Plastics News December 2017

TECHNOLOGY

New material lowers the energy consumption associated with ethylene

production

cientists from ExxonMobil and the Institute of Chemical industrial processes." Ethylene is a vital component in the
STechnology (ITQ) of Valencia's Polytechnic University production of chemical and plastic products frequently
and the Spanish National Research Council (CSIC) have used in day-to-day life, making the search for alternate
developed a new potentially revolutionary material which technologies to separate ethylene from ethane with a
could significantly reduce the amount of energy and low energetic consumption turn into a very active field of
emissions associated with the production of ethylene. investigation. Although chemical product manufacturers
This new material, along with other separation processes, have evaluated a series of alternatives to cryogenic
could lead to a reduction of up to 25 per cent of the energy distillation, including new adsorbents and separation
currently necessary for the separation of ethylene, as well processes, the majority of these alternate technologies
are hindered by low selectivity and efficiency, as
well as the impossibility to regenerate adsorbents
as they decompose with use due to the presence of
contaminants.
The new ITQ-55 material is capable of selectively
separating ethylene from ethane thanks to its exclusive
porous and flexible structure. Created by heart-shaped
units interconnected by large and flexible channels,
the new material enables flatter ethylene molecules
to pass, while negating access to the rounder ethane
molecules. Therefore, the new material acts as a flexible
molecular sieve.
as the associated carbon dioxide emissions. Researchers
at ExxonMobil and the ITQ have discovered that the new "The ITQ-55 is a very interesting material, whose
material, composed of a silica zeolite with a unique unique combination of pore sizes, topology, flexibility
structure, can be used in gas separation processes such as and chemical composition leads to a highly stable
recovering ethylene from currents that contain ethane and and chemically inert material which is able to adsorb
ethylene. Zeolites are microporous materials commonly ethylene and filter out ethane," explains CSIC research
used for adsorbent and catalytic purposes in chemical professor Avelino Corma, coauthor of the investigation.
processes. In the case of the ITQ-55 zeolite, separation is "We are thrilled with this discovery and hope to continue
performed with an unprecedented degree of selectivity at our fruitful collaboration with ExxonMobil," he adds.
room temperature. Investigation results could also apply
to the design of new materials to be used as adsorbents Additional research must still be done before the
or membranes in different applications of gas separation new material can be considered for large-scale
associated with the fabrication of chemical products. commercialisation. Further research will be centered
"Cryogenic distillation, the procedure which is currently on incorporating the material to a membrane for its
used to separate ethylene on a commercial scale, is a industrial use, as well as developing new materials for
process which consumes a lot of energy," explains Vijay gas separation. "Our end goal of replacing cryogenic
Swarup, research and development vicepresident for the distillation is a long-term challenge that will require
ExxonMobil Research and Engineering Company. "If this many more years of research and tests in and outside the
new material is applied at a commercial scale, it could laboratory," Gary Casty, head of ExxonMobil Research and
significantly reduce the amount of energy and emissions Engineering Company's catalysis section adds. "Our next
associated with ethylene production. This is another steps will be focused towards a better understanding of
excellent example of collaboration between industry and the potential of this new zeolitic material." ExxonMobil's
academy, centered on promoting solutions to improve goal is to improve industrial efficiency to meet the
energetic efficiency and reduce the carbon emissions of increasing energy requirements of the world.

Plastics News December 2017 58