Thursday, February 6, 2014

UT membrane able to separate hot gases

Considerable potential energy savings for the chemical industry with hybrid gas separation membrane

Researchers at the MESA+ research institute at the University of Twente have developed a new type of membrane for separating gases in the chemical industry. What makes the hybrid unique is that it can also be used at high temperatures and high pressures. The polymer membranes that are currently used do not work at such conditions. This development potentially offers the chemical industry (which is responsible for more than a third of national energy consumption) considerable energy savings. The researchers published their research in the prestigious scientific periodical Journal of the American Chemical Society.
The chemical industry is responsible for one third of the energy consumption in the Netherlands. Approximately 40% of the energy is used for separation processes in which the products of chemical reactions are separated from each other. Researchers at the University of Twente have now developed a new type of membrane that allows to separate gases from each other in an energy-saving way, even under extreme conditions.


Currently, gases are separated via processes such as of cryogenic distillation, during which gases are liquefied by intensive cooling, or through absorption processes. The disadvantage of these methods is that they often require a large amount of energy.
Using membranes that selectively allow one gas through but retain another allows energy-efficient separation. However, up until now there were no suitable organic membranes available that also performed at high temperatures and high pressures. Conventional, organic membranes are made of polymers and are not stable enough at high temperatures. The membrane developed by researchers at the University of Twente, which comprises of both organic and inorganic components, remains effective at high temperatures (of up to 300 degrees Celsius) and high pressures. This offers advantages for gas separation in the chemical industry, as many processes involve high temperature and high pressure conditions. The researchers have applied for a patent for their invention. 


The membrane is approximately 100 nanometers thick (10,000 times thinner than a millimeter) and consist of ceramic nanoparticles that are bound to each other at multiple points by long-chain organic molecules. These then form a sort of three dimensional web (with the nanoparticles as the junctions) and this web allows certain gases to pass through and retains others. As it is possible to choose the length of the organic molecules used (and therefore how fine the web is), it is easy to design suitable membranes for all kinds of applications. An added advantage is that the hybrid membranes are relatively easy to produce on a large scale, as the techniques used are compatible with those for producing the conventional membranes often used in water purification.


Researchers from the Inorganic Membranes and Materials Science and Technology of Polymers departments at the MESA+ research institute at the University of Twente carried out the research as part of the UT's Green Energy Initiative. Researchers cooperated with Aachen University on this project. The research is part of the CARENA project funded by the European Union.