By Ron Marshall for the Compressed Air Challenge
A grain products company was increasing their production capacity and needed a new compressor and dryer. The budget was tight, so the company searched and found some used equipment to meet the need.
Rather than running the lubricated compressor in modulating mode like the previous compressor, the company purchased very large storage receiver capacity to enable the compressor to operate in load/unload mode with timed shutoff. This enabled the compressor to turn off between cycles during light loads, saving energy.
Since the compressed air piping was run outdoors, a used desiccant dryer was purchased to maintain -40 dew point. A dryer with dew point dependent switching was selected to reduce the amount of purge air required, saving even more energy and qualifying for a substantial power utility incentive.
The equipment was installed and a compressed air verification measurement was done to ensure the expected savings was being realized. The audit showed that the air compressor loading was much higher than expected and an investigation was conducted to determine the cause.
Careful measurements showed that the plant flow was actually within expectations, but the air dryer was unexpectedly consuming about 5 times the rated purge flow! An inspection of the dryer revealed that a purge flow orifice (which, in this case, is just a washer with a hole drilled in it, installed in a union) was missing, it had been lost when the air dryer was disassembled and moved to the new location. Repairs were done and the compressed air loading returned to normal.
Learn more about air dryers in our next Compressed Air Challenge seminar in your area. Visit www.compressedairchallenge.org for more information.