Compressed Air Best Practices - June 2008 - (Page 38)

| 06–07/08 Compressed Air Industry PHARMACEUTICALS | UTILITY GRADE COMPRESSED AIR SYSTEMS Plant managers demand production uptime without regard for compressed air operational cost. This leads to maintenance personnel responding to problems from the production floor by adding compressors, modify piping and/or increasing compressed air pressure to keep their “customers” happy. Unfortunately, this “band-aid” approach unnecessarily drives up costs by not addressing root causes. These changes become part of the system adding complexity and inefficiency. A common practice is to turn on backup compressors when a pressure situation occurs on the production floor. These compressors often remain on even after the event is over, driving compressors to operate in a “modulated” mode. Air compressors are most efficient at 100% of full load or completely turned off. Air compressors are typically operated in a “modulated” mode (<100%). For example, a compressor running at 60% of its full load capacity may use 90% of its full load energy. Unloaded or idling compressors use 25% of their full load energy. This is an inefficient way to operate the system because of the amount of energy required to run in a modulated environment. Some facility personnel will modify an existing compressor by adding a variable speed/frequency drive (VSD/VFD) and operate this machine in a trim configuration to address the issue of modulation. Operating in a trim mode attempts to balance output with energy input. Unfortunately, without an overall control scheme, the remaining operating compressors run partially loaded (modulated mode) and continue to waste energy. Having multiple component manufacturers, maintenance and control personnel are at a disadvantage. This lack of standardization challenges maintenance staffs because they lack the extensive knowledge and expertise required to service and monitor the different machines. Without a central control system, it is necessary to rely on the individual controls of each machine. Machines from different manufacturers usually cannot communicate in an integrated, synchronous manner. This causes each machine to run independent of the other, leading to further significant pressure fluctuations in the distribution system and energy waste. Characteristics of a Utility Grade Compressed Air System The characteristics of a utility grade compressed air system are: Decoupled Supply from Demand p Pressure-Flow Controller and Adequate Storage • • • Allows compressors to operate and maintain storage pressure within a control band, independent of demand requirements Ensures that distribution headers remain at constant pressure regardless of demand Allows the efficient sequencing of base/trim load compressors Supply Side p Air Compressors • Trim unit(s) with VFD(s) modulate to ensure base units remain completely on or off p Filtration • • Pre-dryer filtration ensures impurities are removed prior to air entering the dryer Post-dryer filtration ensures impurities are removed prior to air entering the distribution system p Dryer • Adequately sized to ensure required dew point and flow rate p Storage • • • Adequately sized to allow control system to efficiently operate the compressor(s) Allows pressure-flow controller to stabilize pressure under high load conditions Allows system to ride through demand events minimizing the running of additional base load compressors p Auto-Drain and Oil Recovery • • Reduces air loss Protects environment p Heat Recovery • • Per needs of the facility Saves heating costs p Control and Monitoring System • • Ensures reliability, efficiency and cost savings by optimizing the operation of compressors May also be used for heat recovery, dryer operation, data collection and allocation of operating costs 38 www .aii rbe stp rac tic es.com ai b t p racti tices com http://www.airbestpractices.com

Table of Contents Feed for the Digital Edition of Compressed Air Best Practices - June 2008

Compressed Air Best Practices - June 2008 Contents From the Editor Utility-Air News A Pharmaceutical Compressed Air System Audit Talking Dew Point Puerto Rico, Pharmaceuticals and Airequipo Inc. Oil-Free Rotary and Oil-Free Centrifugal Compressor Comparison SMC: Managing Energy and Dew Point in Pneumatic Systems Utility Grade Compressed Air Systems Training Calendar & Product Picks Wall Street Watch Advertiser Index Job Market

Compressed Air Best Practices - June 2008

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