Industrial Utility Efficiency    


In terms of compressed air systems, it’s not unusual to see a plant with 10 to 15 air compressors, each of which is rated to provide 3,000 to 4,000 scfm of air. The air is used for everything from moving product, to powering pneumatic tools, pumps, and fans, to cleaning. There are easily 1,500 pneumatic control valves at a single plant.
For many industrial sites the only indicator of compressed air performance is the big old pressure gauge right outside the maintenance manager’s office. Over the years someone may have penciled a red line on the gauge, and if the pressure falls below the line the manager will start shouting. This is an example of the saying “ What gets measured, gets managed”, definitely the plant pressure in a facility is a very important indicator of adequate compressed air system operation, but is it the only parameter that needs to be monitored? This article explores some important compressed air KPI’s and provides some examples of how they can be collected and used.
One of the strategies discussed in Compressed Air Challenge® seminars is to use remote sensing to better control multiple air compressors.  The use of a pressure signal from a common location downstream of air dryers and filters allows air compressor controls to “see” the downstream pressure better and provide more accurate pressure control. A characteristic of this strategy that is often missed is that remote sensing can also provide better pressure control for single compressor systems, where only one compressor normally runs to feed the plant loads, and can result in lower average compressor discharge pressure and lower more accurate plant pressure regulation, which saves energy.
To gain about one horsepower of mechanical energy from a compressed air powered motor it costs seven times as much at the input of the air compressor. And surprisingly between 20 and 30 percent of this valuable power is lost even before it gets to the end use. Further to this another 10 percent is lost to artificial demand caused by higher than required pressure, and to top that all off, another 10 percent is wasted by equipment that is either inappropriately supplied with compressed air or left to consume air even when the associated production machine has been turned off.  
Compressed Air Best Practices interviewed Gregory Rhames, Asset Reliability Manager/Energy Manager at Verallia. As background, Verallia is the packaging division of Saint-Gobain. Verallia employs 15,500 people globally and makes about 25 billion glass bottles and jars each year. We employ 350 people at Madera where we produce about 1 million wine, champagne and sake bottles per day.
Production and quality engineers in industries like the food & beverage, pharmaceutical, semiconductor, and chemical sectors have established internal specifications for oil-free compressed air. The product spoilage and safety issues at risk make oil-free compressed air an absolute necessity in certain processes.
Many times, the hierarchy of making improvements in your compressed air system will begin with the larger equipment. If your compressor is outdated, inefficient or sized improperly for your plant, the cost of replacing it may scare you away from proceeding down the efficiency path. It is also typical to first concentrate on updating the controls of a compressor to best match peak demands and lulls in the need for air and, while this is a very good step to take in your overall plan of attack, it can also burden your budget.  
Dewpoint is defined as the temperature to which a gas (e.g. air) must be cooled, at constant pressure, for water vapor to begin to condense to liquid water. In other words, when the dewpoint temperature has been reached, the gas is fully saturated with water vapor.
Sitting on his desk the day Brian began his new job as Plant Engineer for Carbo Ceramics’ McIntyre, GA facility was a proposal to purchase a new 150 HP air compressor as a backup machine. The facility already had six of these machines and, yes, all six ran almost continuously.
The secret to success is to understand the nature of what type of leak produces a detectible ultrasound and what does not, along with the techniques that can be used for effective leak identification.
Most facilities don’t prioritize the cost of operating compressed air systems—they just want to get the job done. A recent market study1 found that only 17 percent of compressed air users valued efficiency as a compressed air system management goal. Nine percent were concerned with containing energy costs. Seventy one percent simply wanted to deliver a consistent, reliable air supply.