Compressed Air Best Practices - January 2009 - (Page 12)

| 01/09 Focus Industry ENERGY REBATES | COMPRESSED AIR AUDIT OF THE MONTH Nitrogen System Innovation at Boeing Large Storage Because of this very high peak flow, Boeing had installed a large 30,000-gallon receiver to stabilize pressures and reduce the required size of the nitrogen generator. The plan was to charge this receiver to high pressure using the main screw compressor as a booster. This strategy required that all of the gases, even the waste stream vented to atmosphere, be boosted to high enough pressure to provide an adequate reserve. This pushed the specially designed screw compressor to its design limits and forced it into modulation mode, where it produced less and less air as the storage receiver filled up. Due to the characteristics of membrane style generators, this lower air flow increased the purity of the nitrogen produced, but also significantly increased the losses of the system, with the membranes venting more and more gas per unit output. In fact, much of the time the unit operated with no nitrogen output, with all the produced gas being vented directly to atmosphere. Variable Speed Compressor efficiently matches the nitrogen generator demand Old System Pressure Limited This system was at a real disadvantage in terms of Nitrogen storage. The high-pressure screw compressor was limited to an output of about 175 psi. Since the required pressure for the autoclaves was 100 psi, this left only 75 psi of differential in the large storage tank that could be used to supplement peak flows. This equates to about 20,700 cubic feet of reserve, far short of the 69,000 cubic feet that was needed for an autoclave fill to the maximum pressure. Since the old nitrogen generator could only produce about 150 cubic feet per minute of nitrogen, the shortfall had to be covered by expensive liquid nitrogen reserves. Innovative Solution To solve their nitrogen production shortfall, and provide increased capacity for future production expansion, Boeing approached Air Liquide, a leading supplier of industrial and medical gases, for a new solution to its nitrogen needs. Boeing challenged the company’s engineering team to not only design a system with increased output capacity, but to do it at reduced energy costs. The team successfully met the capacity requirements and greatly exceeded Boeing’s energy cost reduction expectations. A new system was installed that could produce enough gas to supply Boeing’s peak nitrogen demand for the foreseeable future and provide an innovative staged production process that can be shed in steps to take the nitrogen production “off peak” — saving significant utility peak demand charges. 12 www.airbestpractices.com http://www.airbestpractices.com

Table of Contents Feed for the Digital Edition of Compressed Air Best Practices - January 2009

Compressed Air Best Practices - January 2009 Contents From the Editor Utility-Air News Compressed Air Audit of the Month: A Nitrogen Audit at Boeing Air Standards: New ASME & ISO Standards for Compressed Air System Assessments Energy Rebates Assist Industrial Sustainability Initiatives Seven Sustainability Projects for Industrial Energy Savings: Project #1: Lighting Optimization Minimum Supply Wire Size Recommendations for Compressor Packages Utilizing Variable Frequency Drives The Pneumatic Advantage: Pneumatics Bring Precision and Reliability to Furniture Industry Specialist Personal Productivity: Is Afternoon Fatigue Influencing Your Job Performance? The Explanation and Some Solutions. Resources for Energy Engineers: Training Calendar & Product Picks Wall Street Watch Advertiser Index Classifieds

Compressed Air Best Practices - January 2009

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