Industrial Utility Efficiency    

Air Compressors

As an end user, have you ever heard the message to put in the biggest VFD air compressor, and the system will always be reliable and efficient.  Why do an audit?  Just add up the compressors on site and put one VFD for that size or larger.  Why have the complexity of multiple compressors, storage, sequencing, etc?  Even better, put in two of them, one for the whole system, and one for back-up.  If you could wave a wand, wouldn’t that be what every system should look like?  Perfect peace and efficiency, with 100% confidence of reliability.
Having set a goal to reduce their own energy intensity by 20 percent by the year 2020, Atlas Copco has also set the ambitious target for the energy consumption of the products they sell. Using the Global Reporting Index as the way to establish metrics, there is real substance behind the sustainability program at Atlas Copco.
Any time you troubleshoot a large motor drive, you run the risk of both electric arc and electrical shock. Arc blasts are less frequent but deadly. They’re most commonly caused by a dropped wrench or other tool that lands across high-energy bus bars in an open cabinet. This kind of short circuit is upstream of protective fuse links and lets loose thousands of amperes of fault current.
Most P.E.T. bottle-blowing machines require anywhere from 550 psig (38 barg) to 580 psig (40 barg) and an air flow of 247 cfm FAD (420 m3/hr) to 3700 cfm FAD (6290 m3/hr). The air compressor technology used most prevalently for this application is the double-acting, oil-free, water-cooled, reciprocating air compressor. With the higher pressures and air flows that are required, the P.E.T. bottle blowing market is a strong niche market for the double-acting oil-free reciprocating (piston) compressors.  
Several days prior to our visit, during a cold winter evening, the lead air compressor in one mechanical room tripped off (apparently due to a fouled intake filter and low air flow through the machine). A crucial situation then developed: The "stand-by" unit did not start. Maintenance folks had to be called in to get a compressor running. That delay caused low plant air pressure, production curtailment and some defective product. They had yet to determine the conditions that caused the "no-start".
Production processes get their energy from the air stored at higher pressure in the piping distribution system. The air compressors simply replenish the air that is consumed. It is an important distinction to make. The energy input in compressing the air is supplied to the connecting pipes for delivery to the various demands throughout the facility.
In the realm of pharmaceutical production and packaging, the two most important factors with compressed air are reliability and quality. In pharmaceutical plants, our customers have emphasized this reoccurring theme over and over to paint the clear picture that reliable and high-quality air are king.
The $mart Sequencer® is an air compressor control system designed to reduce a plant’s energy costs by continuously monitoring system demand and automatically selecting the most energy efficient combination of available air compressors.
Compressed air system controls match the compressed air supply with system demand and are one of the most important determinants of overall system energy efficiency. This article discusses both individual compressor control and overall system control of plants with multiple compressors. Proper control is essential to efficient system operation and high performance.  
The goals of this article are to show why sequencers often have problems, and to demonstrate how avoid problems by proper system integration and controls design.
When was the last time you visited your compressor room? A week ago? Several weeks ago? If you are like many, you went in for the last scheduled maintenance interval and have rarely been back since. Air compressors, dryers and other air system components have become more reliable and self sustaining from a maintenance standpoint with each generation, requiring less and less human intervention.