The failure of a plant’s instrument air system can result in serious malfunction, loss of control, and many safety issues. Most problems with instrument air systems can be resolved with proper understanding and maintenance of the system as a whole including air compressor packages, dryer systems, instrument air distribution system, and others. This article discusses air compressor packages for instrument air systems, specifically dry screw compressors, and provides insights into possible operation and maintenance difficulties and how to avoid them.
Oil-free reciprocating compressors for very small units and oil-free integrally-geared centrifugal compressors for very large packages have been used. For more on reciprocating compressors and considerations for their maintenance and reliability.
Air compressors are most often positive displacement compressors. Integrally-geared centrifugal compressors have sometimes been used for very large applications. But, the majority of air compressors are dry screw compressors for medium-sized applications. There should be no lubricant or oil within the compressor chambers regardless of what type of compressor is used. On this basis, dry screw compressors are employed for a wide range of small- and medium-sized (including some large-sized) applications.