Oil and Water Don’t Mix – Keeping Your Condensate Hydrocarbon-Free

We frequently discuss the differences between oil-free and oil-injected air compressors and their uses in various industries. While oil-free compressors are essential for pharmaceutical, food and beverage, and semiconductor production, oil-injected compressors are great for operation in harsh environmental conditions like those found in oil and gas, railway and marine applications. However, one issue that is often not considered is what happens to lubricant after it’s used in an oil-injected compressor.

How do I know if I need an oil-water separator?
If you have an oil-injected compressor, then you need an oil-water separator. When air is compressed by an oil-injected machine, it contains various contaminants that need to be filtered out including water vapors, oil aerosols and particulates. As the compressed air cools, the aerosols and vapors condense into a liquid mix of oil and water called condensate. Compressed air filters use specific methods for removing aerosols, vapors and particles, but condensate is caught and drained from the system.

Untreated, this condensate poses an environmental risk. Because of strict quality limits set by the EPA, any water reintroduced into the municipal system must meet certain regulations. To meet these regulations, the oil must be removed from the condensate before disposal. Oil-water separators are specially designed for this task, but it’s important to know whether one comes standard in your compressor system or if you will need to purchase one separately.

Many large oil-injected compressor skids include an oil-water separator. Smaller oil-injected compressors, like those used by hobbyists, might not include an oil-water separator. However, this does not mean they are not subject to local and federal water standards. To ensure condensate meets acceptable oil ppm (parts per million) levels, users of compressors without integrated oil-water separators must purchase them separately.

How does an oil-water separator work?
Oil-water separators operate on the principles of adsorption. Adsorption works on the molecular level to attract and hold on to specific elements or compounds. In oil-water separators, these adsorption filters are oleophilic, meaning they have an affinity for oils. The oils adsorb to the filter media as the rest of the condensate continues through the filter.

Most oil-water separators work in multiple stages to ensure all traces of lubricants are eliminated. Sometimes this is as simple as using two types of filter media to remove oils. Other times, the process involves sending condensate through towers, each one with a different oil removal method.

Atlas Copco’s new OSS oil-water separator
Atlas Copco’s new OSS oil-water separator is small enough to mount on walls next to oil-injected compressors, but still maintains excellent filtration capabilities. It’s easy to install and replace, and all materials are 100% recyclable to further protect the environment.

Are you properly treating your condensate before disposal? Work with a compressor expert to find an oil-water separator that will help keep your condensate – and our world – clean.

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Collecting and Removing Condensate Key to Compressor Health

Three Ways Your Air is Not as Fresh as You Think

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