Compressed Air Best Practices - March 2008 - (Page 29)

Compressed Air Industry FOOD PROCESSING | 03/08 | With a multitude of individual dryers in the system, there is a good probability that one of the dryers can be serviced or maintained without significant disruption to the compressed air system. That is, of course, dependent upon how the dryers are connected within the air system and whether the offline dryer is of particularly large capacity. It is plausible that such a system may only use the dryers that are needed for a given load situation. This may require manual activation of the standby dryers to address increases in compressed air usage if an automated control system is not in place. The shortcomings of this approach are numerous. With dedicated power, air and possible water connections, this scenario is the most expensive to install. In addition, without being able to take advantage of economies of scale with the equipment, this approach also has a very high capital cost. Lastly, taking into account not only the physical size of the dryers but the access area required around each, this approach predictably uses the most real estate in the compressor room. b) One Large Non-Cycling Dryer Initial Capital Cost 5 Cost of Operation 3 Installed Cost 5 Footprint 5 Continuity of Operation 0 Maintainability 0 Ranking Total 18 Purchasing the exact amount of dryer for a given compressor output will translate into the optimal capital cost. With a single connection, installed costs are also quite favorable for this approach. Taking into account the service area requirements for a single dryer, this approach is among those that consume the least amount of floor space in the compressor room. Provided the sizing of the dryer matches the compressor capacity and provided the air usage does not vary, the cost of operating this dryer would be very desirable. However, most all facilities have varying load profiles, taking into account varied processes, shift changes, reduced workload, etc. A non-cycling dryer will continue to operate at full load regardless of the compressed air load. Such operation can result in significant energy consumption during times of low compressed air usage. With the economical upfront cost of this approach, it may be difficult at first to see its shortcomings. That is until one considers the “what if” of component failure or maintenance requirements for the dryer. By using this all-eggs-in-one-basket approach, failure of even a simple component in the dryer could shut the entire compressed air system down. Similarly, if the compressed air system approaches a 24-hour per day, 7 day a week operation, opportunities to conduct preventative maintenance on the dryer are minimal. Avoiding preventative maintenance will only result in more frequent and unpredictable component failure. c) Two Large Non-Cycling Dryers Initial Capital Cost 1 Cost of Operation 3 Installed Cost 2 Footprint 2 Continuity of Operation 4 Maintainability 5 Ranking Total 17 With 100% backup, this approach takes into account the peril that can result from poor planning for maintenance and component failure. However, with the dryer valved off from the air system, it will only be after a failure has occurred and the downstream process is interrupted that the standby dryer is operational. Conceivably, sensitive processes may be severely impacted during the time between the dryer failure and the activation of the standby dryer. This approach does, however, allow for preventative maintenance on the standby dryer — a measure that will likely have a positive effect on the continuity of operation of the online dryer. Since the design of the dryers in this approach match those of scenario “b),” the same operational cost caveats apply. d) One Multi-Module Cycling Dryer Initial Capital Cost 4 Cost of Operation 5 Installed Cost 5 Footprint 5 Continuity of Operation 5 Maintainability 5 Ranking Total 29 This approach ranks highest when considering the comprehensive requirements of a well-designed system. ZEKS Compressed Air Solutions, West Chester, Pennsylvania examined the broad requirements and associated implications faced by large-scale manufacturers and used the findings to guide development of the MultiPlex™ multi-module dryer concept. What resulted is a large capacity dryer composed of multiple modules, each of which is comprised of a dedicated refrigeration www.airbestpractices.com 29 http://www.airbestpractices.com

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

Compressed Air Best Practices - March 2008 Contents From the Editor Utility-Air News The Compressed Air Audit of the Month: Saving Energy with Blowers in Canada Do You Provide World-Class Service? Managing Rotary Screw Air Compressors at Midwest Bakery The Difference Between Acfm and Scfm for Proper Vacuum Sizing Best Practices — Multi-Module Process Air Dryers The Vacuum Formation Process in Building Compressed Air Filter Elements Solberg Manufacturing Real World Best Practices: Measuring Pressure Dewpoint in a Compressed Air System Resources for Energy Engineers: Training Calendar & Product Picks Wall Street Watch Advertiser Index Job Market

Compressed Air Best Practices - March 2008

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