Plant Services - December 2007 - (Page 23)

EFFICIENCY Steam Systems the boiler is leaking, heavily scaled, or has outdated burners and controls, Steamer has made it his home and it’s probably time for replacement. If the boiler is in good shape, it might only need efficiency retrofits such as an updated burner or combustion control system, which can save 50% on capital costs compared to a new boiler unit and provide significant fuel savings at least equal to the retrofit cost during the first year. Auditors also investigate whether the boiler has been overheating. If the boiler overheats, there might be problems with either the boiler’s insulation or gasketing, which could lead to damaged and unsafe equipment. The cost of repairs to correct these types of problems are relatively nominal when compared to the serious safety or mechanical repair issues that can result if you let the Steamer flex his energysapping muscles unchecked. The auditor will perform a combustion test using stack gas analysis equipment to quantify boiler efficiency. This could lead to the recommendation of an oxygen sensor/transmitter in the exhaust gas. The sensor/transmitter continuously senses oxygen content and provides a signal to the controller, which adjusts the air damper and gas valve to maintain a consistent oxygen concentration in the flue. This minimizes excess air while optimizing the air-to-fuel ratio and puts the Steamer on the run. Oxygen trim systems typically increase efficiency by 1% to 2%, which, if you’re looking at energy bills in the millions, means saving $10,000 or more each year. the diameters of the piping, controls, steam traps and control valves allow operation at lower pressure, knowing velocities and pressure differentials will be changing. If it’s concluded the pressure can be reduced, fewer BTUs will be used per hour in the process, saving the facility those energy dollars. Minimize stack temperature Stack temperature also is something to consider when looking for ways to be more efficient. A well-tuned boiler should operate between 50° to 100° above saturated steam temperature. If it operates at higher levels, fixing the problem begins with maintenance and cleaning. From an efficiency standpoint, every 40°F in temperature reduction results in a 1% fuel savings and provides much frustration for the Steamer. Sometimes, the stack temperature is higher because there’s soot on the fireside surfaces caused by improper air/fuel ratio control. This means the burner was operating with excess fuel (rich), causing fine black particles, How is steam applied? EMERGING MARKET CONTENT The next step in the audit process is to determine what the steam is used for, how it’s applied and if it’s possible to reduce the operating pressure to reduce the sensible heat required to produce a pound of steam. To determine this, the heating process is reviewed along with the existing piping layout to see whether December 2007 DISCOVER W W W.DISCOVERCURTIS.COM ©2007 Curtis-Toledo, Inc. www.PLANTSERVICES.com 17638_2 07 CTGNL GENRL Emerging.indd 1 23 9/19/07 7:30 http://www.discovercurtis.com http://www.discovercurtis.com http://www.PLANTSERVICES.com

Table of Contents Feed for the Digital Edition of Plant Services - December 2007

Plant Services - December 2007 Contents From the Editor: Orange Alert The PS Files: Pressed into Innovation Up and Running What Works: Samuel Adams Facility Refreshed in Cincinnati Energy Expert: Energy's "Perfect Storm" Technology Toolbox: Know Your Position Cover Story: Get a Grip on the Steamer Piping: Outside Looking In Web Hunter: Potpourri X In the Trenches: Making a Big Stink Boiler Room: Getting Educated

Plant Services - December 2007

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