The Molecular Sieves market today is finding new outlets with the emergence of medical oxygen concentrators for home use. CECA, via its R&D activity, offers its customers increasingly innovative solutions for miniaturizing devices.
To have an oxygen rich air supply on hand is a necessity for a large number of people suffering from chronic respiratory failure. As a result of smoking, pollution and an ageing population, demand is on the rise for devices that are capable of producing this “precious” gas.
Medical Oxygen concentrators for home use trap the ambient air and release a flow of >90% pure oxygen. This is not as easy as seems when we take into account the fact that this molecule represents only 21% of the air we breath (while nitrogen accounts for 78%). The explanation is in the way these devices use molecular sieves, an area which has become a specialty for scientists working at the Lacq Research Center (GRL).
These Molecular Sieves are capable of separating the various gases in the air. This is thanks to the highly porous material they are made of called Zeolithe. A combination of silica and aluminum organized into a crystalline network, Zeolithe preferentially traps nitrogen molecules in its nanometer-scale cavities, while letting O² molecules through. This process, linked to polar interactions, whereby nitrogen is retained within the zeolithe, corresponds to the physical phenomenon of adsorption on the basis of which the molecular cartridges fitted inside oxygen concentrators operate.
The development of these Molecular Sieves is the result of CECA’s long-standing experience in this field. Since the late 1980s, a number of industrial sectors, like the iron and steel industry, have already benefited from the technological solutions to produce oxygen. In order to make possible the switch to medical applications, several technological barriers had to be overcome. Tens of tons of zeolithe beads are needed to fill the columns of industrial concentrators, whereas just a few kilograms are sufficient in medical concentrators.
One of the technological challenges met by CECA was reducing the size of its beads, while still retaining their manufacturing principle of zeolithe powder agglomeration.
Development work by CECA teams had also made it possible to enhance the performance of molecular sieves. “We are seeking to produce zeolithes with superior adsorption capacity, superior selectivity, and superior kinetics”, explains Cécile Lutz, Research Engineer at GRL. So our role consists in identifying the type of zeolithe to be used: what chemical nature to select, what morphology for crystals, what size beads, what type of binder and in what quantity, etc.” After taking up these scientific and technical challenges in the late 1990s, CECA’s Research and Development teams have developed new Molecular Sieve grades intended for emerging applications.
In the end, patients will be able to have their own truly portable devices. A prospect which, for them, will mean much greater autonomy. Current devices still present a certain constraint because of their size. They weigh on average 20 kilograms, 2 of which are zeolithe beads. In the future, these concentrators will also be less noisy and more energy-efficient. The group’s R&D is pursuing its drive for innovation while focusing on client requirements. “We are now working on even smaller beads, with much smaller quantities of product per concentrator that, in the future, could be of the order of 100 grams or so only” adds Cécile Lutz.
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