Compressed Air Best Practices - February 2009 - (Page 10)

| 02/09 Focus ndus Focus Industry POWER PLANTS Foc s Industry POWER PLANTS Focus Indus ry POWER PLANTS str O ANTS AN | CO2 O C onth of the M Air Audit d ompresse ler Soot Boi lowing in B r Plants Powe , an Ormer y Hank V er USA B Air Pow kW Be Best Practice Guidelines for Boiler Soot Blowing Uti Utilities have been cleaning their boilers for many years using either steam or high-pressure air air. In the past, when air was used, due to the size of the boilers and the reasonable quality of fuel used, a relatively small amount of cleaning was required. In the past decades, larger power-generating stations were built and the quality of fuel deteriorated requiring a greater amount of cleaning with shorter cleaning cycles. With these changes, larger compressors became a necessity when air cleaning. Reciprocating compressors were unable to compete on an economic basis in the larger capacities due to their relatively small capacities, initial cost, high installation costs and spa space requirements for multiple compressor installations. Centrifugal compressors have been used in utility soot blowing in a limited amount since the early 1950s, but the reliability and efficiency of early high-pressure designs left a great deal to be desired. From the late 1960s through the early 1980s, compressor manufacturers made great strides in the development of the high-pressure, multi-stage, centrifugal air compressors, utilizing the advances in centrifugal technology and manufacturing capabilities. They extended these advances in efficiency, reliability and compactness to the high-pressure units (300 to 500 psig). This makes them the most viable option for economic, large-volume, high-pressure compressed air, such as required in a soot blowing system. February Audit of the Month Where: Midwest, United States Industry: Coal-Fired Power Plant Issues: Older Compressor Technology Audit Type: Supply and Demand Side System Before Audit Operating Hours: 8,760 hours Power Cost (kWh): $0.06 Low-Pressure Air (100 psig): Ash Air: Control Air: Station Air: Subtotal: High-Pressure Air (300 psig): Total Air Flow: 1,469 scfm 1,212 scfm 2,334 scfm 5,020 scfm 7,480 scfm 12,500 scfm Air vs. Steam for Soot Blowing in Boilers Generally speaking, soot blower manufacturer’s lances, with some modifications, will handle either cleaning media steam or compressed air. Cleaning energy is usually defined as: Fluid horsepower = WV (Px 144) 33,000 Where: W is V is P is flow in lbs/min specific volume in ft3/lb psig at the nozzle Total Energy Cost: $2,449,876 Audit Actions: 1. Boiler soot blowing best practices 2. Install new 1,500 horsepower, centrifugal air compressor with more effective turndown for 300 psig air Audit Results: Low-Pressure Air (100 psig): 4,020 scfm High-Pressure Air (300 psig): 6,730 scfm Total Air Flow: 10,750 scfm Air Flow Reduction: 1,750 scfm Total Energy Cost: $1,062,238 Total Energy Savings: $1,387,638 Energy Savings %: 43% Project Cost: $1,462,700 Simple Payback: 12.6 months 10 www.airbestpractices.com http://www.airbestpractices.com

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

Compressed Air Best Practices - February 2009 Contents From the Editor Utility-Air News Compressed Air Audit of the Month Air Standards Instrument Air in Nuclear Power Plants Seven Sustainability Projects for Industrial Energy Savings The Pneumatic Advantage Personal Productivity Resources for Energy Engineers Wall Street Watch Advertiser Index Classifieds

Compressed Air Best Practices - February 2009

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