25 metres long, 6 metres wide and 7 metres high: These are the dimensions of the largest system segment delivered from the Donaldson workshop in Haan. And this segment was just one of several parts of the adsorption dryer unit that was installed in a large chemical plant which now processes 66,000 Nm³/h of compressed air. Adsorption technology even withstands the test with extremely large flow rates to eliminate moisture and gaseous contaminants from compressed air and technical gases.
In the case of standard applications, standard adsorption dryers (Chart 1) are used. Donaldson offers an extensive range of products, ranging from the economic and compact “terminal dryers” through the new high pressure dryers up to the highly efficient heat regeneration “heat of compression” adsorption dryers.
Extensive experience
With this range of products, nearly all requirements of compressed air processing can be covered to provide dry, clean, and oil-free compressed air even for challenging applications such as semiconductor production. There are, however, applications where the systems must be individually adapted to the operational conditions – and exactly this is the task of our business division “Systems Engineering”.
Processing of technical gases
Special installations are for example required if – as described above – extremely large amounts of compressed air must be processed. One single
“tailored” large-scale system performs this task much more economically than several standard dryers. Frequently, the engineers of the Systems Engineering division also develop solutions for processing technical gases and gaseous energy sources such as carbon dioxide and natural gas.
Optimum integration into the system
Independent of the medium to be processed, an optimum integration of the dryer into the total system requires comprehensive know-how. Klaus Michel, Technical Manager of Systems Engineering, says: “If the adsorption system is individually developed, it is often possible to remove the regeneration gas as well as the required regeneration heat from the process – thus saving lots of energy. Therefore, the additional costs for a special installation often amortise in a very short period of time. And the extensive experience that we have gathered during many years of systems engineering, ensures that the systems optimally fulfil their tasks. Therefore, we often take unconventional paths and for example build systems with three adsorption vessels in order to conserve the adsorbents and guarantee long life cycles.”
Current projects
One of the most recent projects is e.g. drying systems installed on oiltankers, which process the volatile organic compounds (VOCs) emanating when the ships are unloaded. Donaldson recently commissioned a special installation for a chemical company, which eliminates water, methanol and ammoniac from about 1,200 kg/h of gaseous carbon dioxide at a pressure of 21 bar down to the ppm range. And for the natural gas condensation system (Chart 2) of a Norwegian energy-producing company, our engineers in Haan developed an adsorption dryer which not only extracts moisture from the natural gas, but also CO2 and trace elements such as mercury. The Donaldson systems engineering division is therefore working in a technological field with high growth potential, as liquid natural gas is an energy source with an important future.
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