Evonik’s membrane-based separation technologies act as a filter that allows certain gases to pass through while others remain behind. The design of its SEPURAN range features no moving parts and is considered less complex than techniques such as pressure swing adsorption (PSA).
Commenting on the advantages of its technology, Balster explained, “You don’t need auxiliaries, chemicals or anything.”
“So, if you have a pressurised airstream and you have a membrane, you automatically can produce nitrogen or oxygen enriched air. And this simple process makes it so you can use it for a lot of decentralised production.”
The technology is also useful for situations in which the supply of a particular gas is not enough for what it needs to do. Balster gave an example, saying, “If you have a big air separation tower, a cryogenic unit but then you see in the peak time that you just don’t have enough nitrogen, you can look at the processes where maybe you don’t need such high purity nitrogen, and there you can make just the nitrogen you need with a membrane process.”
The production plant for SEPURAN membrane fibres, Austria.
The advantage Evonik has in the membrane market is that by using its SEPURAN technology it makes its own polymer for different membranes designed for different applications.
“We try always to get the best separation efficiency in each application we serve by changing the polymer chemistry in the background,” explained Balster.
When asked about the growth opportunities in air gases and Evonik’s membrane technologies, Balster said that a lot of opportunities have arisen due to the high demand of air gases and the rising costs.
In addition to nitrogen, he added that demand has increased for oxygen enriched air processes as well as an increased need for carbon dioxide (CO2) separation from natural gas.
As focus shifts to the global energy transition, Balster revealed that Evonik is seeing more opportunities in the hydrogen market.
“Evonik is also making membranes now for electrolysis so that you can create hydrogen from water in principle, but also with our gas separation technology.”
“If hydrogen now in Europe is transported over the natural gas grid, we easily can extract some hydrogen at the end,” he explained.
The topic of conversation then moved on to real world applications of membrane technologies, such as the use of nitrogen generation in the aviation industry.
The SEPURAN nitrogen membrane.
There also exists technology that can create oxygen enriched air that can be used, for example, in the cabin of a plane which is filling with fumes, to ‘protect’ the pilot from suffering from hypoxia or other related conditions.
In addition to this, Balster explained that there are also technologies present on liquefied natural gas (LNG) tankers which generate nitrogen to blanket the LNG. This concept is used, at a smaller scale, within the food transport industry.
“Evonik is currently seeing a lot of requests from the refrigerated container industry, which uses a cold box, and they have nitrogen generation units installed init. You purge the system all the time with nitrogen basically.”
This purging is done to nullify gases given off by food during delivery, such as those emitted by fruits.
CO2 is also emitted, which must be moderated and kept at a certain level to maintain taste and freshness of the food. This moderation is capable of being conducted by using a membrane system.
“Another example is the wine industry, so thereby lowering the oxygen content in the fermentation process, you get the better tasting wine, who doesn’t like that? That’s a favourite of mine!”, remarked Balster.
Other sectors in which membrane systems are used include oxygen enrichment for fitness and health in gyms, this can allow individuals who have, for example, a heart condition to conduct physical training without having to worry about getting enough oxygen.
Because fires require oxygen to combust and to continue burning, such systems can also be used to reduce the oxygen content of a room for both fire prevention and fire reduction.
Balster sees a future in which he has a second button for the oxygen concentration at home, so it can be adjusted to 25% when he’s sleeping at night to optimise his rest, before turning it down to 17% before leaving the house.
“My health is safe, nothing can happen in terms of fire. It would be really great if such systems could be everywhere in the future.”
Part 1 and Part 2 of gasworld’s Air Gases webinar series can be accessed on demand here.