The ambient conditions at the installation site have a very important impact on the performance of a PSA generator:
Higher ambient temperatures = higher feed air temperatures.
Gases expand with higher temperatures, so less feed air mass can be loaded into the PSA adsorption tower during each cycle, as tower volume and adsorption pressure remain constant;
The adsorption efficiency of any molecular sieve for non-cryogenic air separation (also those applied by other PSA generator manufacturers) decreases with increasing adsorption temperatures;
The size of the air compressor for a PSA generator has to be factored in for site elevation. Higher elevations will require a larger air compressor;
So, the produced mass flow of the PSA oxygen or nitrogen generator (expressed in Nm3/h) strongly depends on the actual ambient temperature at the installation site, as can be seen in the following graph:
Assumption: 65% Relative Humidity for all ambient temperatures, installation site at sea level.
As can be observed, the product mass flow of any PSA nitrogen or oxygen generator, independent from its manufacturer, decreases at increasing ambient temperatures. But the feed air consumption expressed in the generally applied performance unit for air compressors, m3/min FAD (Free Air Delivery) at ambient temperature, remains constant or even increases, which is very important to know for the selection of the right air compressor. And this situation even deteriorates at higher relative humidity values!
The consideration of this behavior during the dimensioning of a PSA system is essential, not only to select the correct PSA generator but also to select a feed air compressor with sufficient capacity. We want to supply you with a system that always works. That's why we need to know the altitude and the highest ambient temperature and corresponding relative humidity value at your installation site to supply you with a correctly dimensioned PSA system, which can supply your gas requirements even under the toughest conditions.
