Drop and give me 20!

By: Michael Camber

During a recent set up of a new controller installed to manage three compressors (two 40 hp and one 75 hp), our field rep mistakenly set the system pressure 20 psi lower than planned. A week or so later, during a system check, the technician discovered the error. Meanwhile, the plant equipment ran fine. Nobody in the plant noticed any production issues. So in addition to a 13% power reduction from better compressor management, the customer got another 10% power benefit by running at lower pressure.

We certainly don’t recommend this approach to finding your proper system pressure, but this incident highlights a very common mistake in compressed air systems: many compressed air systems are running at higher pressures than needed. A rule of thumb for typical plant air systems is that every 2 psig increase in pressure requires 1% more power. So turning up the compressors from 100 to 110 psig increases power consumption about 5%. This practice does not increase productivity. It just uses more energy— and often causes premature wear in pneumatic equipment.

If you have any doubts at all (or even if you don’t), we advise turning down the pressure to see if it affects production, but with a conservative approach. Try 1 psi per week until someone in production complains. This is a no-cost solution that immediately saves money. And the bigger the system and the higher your utility rates, the more you save. The added bonus is reducing the volume lost through leaks, and this also reduces flow demand and compressor run time.

If you are trying to overcome pressure drop between the compressor and points of use, the ideal solution is to minimize the source (s) of the pressure drop (e.g. replace clogged filters, make sure ball valves are fully open, replace undersized piping and fittings). And if it does become necessary to set pressure higher, do it incrementally. People tend to bump up the pressure 5 or 10 psi at a time without trying to adjust it back down.

This is a tip you can take to the bank.

For additional tips visit our website!

Root Cause Analysis and Compressed Air

By: Wayne Perry and Neil Mehltretter

Broadly speaking, industrial plants in the United States have been making great strides towards improving processes, reducing costs, and finding new ways to increase profit margins. The desire to reduce waste and better understand daily plant operations has spawned a number of strategies to accomplish these goals. One such strategy is Root Cause Analysis.

Root Cause Analysis (RCA) is a systematic approach to problem solving, commonly applied when there is a significant failure or issue with far-reaching impact. Its goal is to identify the factors of the negative event and determine what needs to change to prevent similar future occurrences. The spirit of RCA is investigative and collaborative in nature, whereby a team works together to discuss and carefully document the findings.

For compressed air, the common issue of wasted energy is a problem that warrants such analysis. According to a survey conducted by the US Department of Energy, approximately 10% of the electricity consumed at a typical industrial facility is for generating compressed air. In some facilities, this percentage can reach 30% or more. Much of this power is wasted in generation due to poor choices in compressor size and lack of controls. Additionally, it’s estimated that half of all compressed air generated is wasted. Despite the widespread waste of compressed air and the potential for optimizing a compressed air system, it is quite often neglected when plant efficiency initiatives are discussed.

In one example, a furniture manufacturer had grown its business and over the years, its compressed air system had grown into a 2400 hp system. Now, with a power bill for compressors over $1 million per year, management felt it was time to take a look at ways to improve the system. An in-depth assessment produced some eye-opening results. The total productive demand on the system could be satisfied with only half of the compressors currently being used. The manufacturer was losing about $500,000 per year on power, about $250,000 per year on maintenance, and had spent about $600,000 in capital for equipment that was not needed.

Unfortunately, this situation is all too common. The tendency in industrial plants is to throw equipment (and power) at compressed air system problems instead of trying to find the root cause of issues like pressure fluctuation. As it turned out for this furniture manufacturer, $500,000 of power costs could be eliminated for less money than they were spending every year on maintenance for equipment they did not need. Very few manufacturers would accept a 50% scrap rate for production inputs, yet it is quite common in compressed air.

This blog entry is an excerpt from our white paper, “Applying Root Cause Analysis to Compressed Air”. To learn more, download the full version of the white paper here.