Compressed Air Best Practices - January 2008 - (Page 17)

Focus Industry ENERGY MANAGEMENT | 01/08 | Operations has been adding pipe headers to protect themselves, Controls has been adding out-of-date compressor control interface schemes and Projects has been throwing money at the problem, only to make the system worse. Maintenance has been in a purely static mode just trying to keep the facility running every day. costs associated with running the plant air compressors totals $1,062,518 per year. The existing centrifugal compressor is using a control scheme known as turn-down. After 30% turn-down, the compressor provides no further electrical down-turn under partial load conditions. The centrifugal air compressor can never consume less than 450 hp even though it remains at roughly 40% of full-load most of a 24-hour day. The lubricated rotaries are worse in that they are set to a control scheme know as Modulation. This means that after you throttle back only 10% you cannot reduce electrical energy any further. This means at 50% of the unit’s output, the compressor is still consuming 90% of its rated energy. Keeping in mind that the 300 hp rotaries consume 330 BHP (Brake Horse Power) you never get below 90% or 300 actual hp consumed. Finally, we take note that the corporation has decided that all primary air compressors must be oil-free machines. This is due to years of having no air treatment equipment and then, when air dryers were installed, they were undersized, so problems with moisture and oil carry-over continued. The corporation has the The Air Compressors The system consists of two separate compressor powerhouses. The North compressor room had three 300 horsepower lubricated rotary screw compressors and one 800 horsepower oil-free centrifugal air compressor. Total installed horsepower is 1700 hp. The South compressor room has two 300 horsepower lubricated rotary screw compressors for a total of 600 hp. The total installed horsepower, therefore, at the smelter is 2,300 hp. It should be noted that two of the 300 hp rotaries were not in operating condition. The average cost per horsepower of the air compressors had risen from $460.00 in 2003 to $744.00 in 2007. Their energy costs were at $.105 per kWH in comparison to a rate of $.065 per kWH in 2003. The difference is staggering. In 2003 each hp cost $460.44 and in 2007 the very same hp costs $744.00 This is a $283.35 increase between 2003 and 2007, or a 61% increase in the cost of electricity between 2003 and 2007. After data logging the installation, we determined that the facility is using 1440 hp in installed air compressor capacity. The electrical energy AMERICAN INGENUITY DISCOVER W W W.DISCOVERCURTIS.COM ©2007 Curtis-Toledo, Inc. www.airbestpractices.com 19282c CTGNL GENRL American.ind1 1 9/4/07 17 4:20:20 PM http://WWW.DISCOVERCURTIS.COM http://WWW.DISCOVERCURTIS.COM http://www.airbestpractices.com

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

Compressed Air Best Practices - January 2008 Contents Focus Industry Features Compressed Air Industry Articles From the Editor Real World Best Practices: Selecting A VSD Rotary Compressor Audit of the Month: Energy Savings in Peru The Low-Hanging Fruit in Pneumatic Systems Mikropor America, Inc. Wireless Sensor Networks: Improve Efficiency in Compressed Air Systems Special Report: The Chicago Pneumatic Compressor Launch in North America The Importance of Measuring Vacuum The Comp-Air Service Co. Special Report: The 2007 NAACD Wall Street Watch Advertiser Index Job Market

Compressed Air Best Practices - January 2008

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