POWER October 2010 - 18

The guidelines are the second major output of NIST-coordinated
efforts to identify and develop standards needed to convert the
nation's aging electric grid into an advanced, digital infrastructure
with two-way capabilities for communicating information,
controlling equipment, and distributing energy.
To access the three-volume NISTIR 7628, go to http://csrc
.nist.gov/publications/PubsNISTIRs.html#NIST-IR-7628
http://tinyurl.com/32d66k4.
Innovative Cleaning of Air Preheater
Coils with Pressurized Liquid Nitrogen
Cleaning air heaters in power plants or recovery boilers has traditionally
involved using high-pressure water, chemicals, or steam.
These techniques, though effective on moderate airside fouling
of heat exchange surfaces, are usually ineffective on the more
tenacious deposits that can develop in coal-fired plants. If these
deposits are not removed by periodic cleaning, heat transfer in
the heaters is reduced, which in turn reduces boiler efficiency
and increases a unit's heat rate. Severe fouling on air preheaters
(APHs) can even reduce a unit's power output.
Air Heater Function and Performance
The role of a power plant's APH is to improve boiler efficiency by
heating the combustion air before it enters the furnace. For each 50F
increase in boiler inlet air temperature, boiler efficiency will be increased
1%. Air heaters can increase plant efficiency by up to 10%.
APH configurations can vary widely. Some units utilize a Ljungström-type
rotary regenerative air heater or a fixed recuperative
tubular air heater. Depending on the configuration, many units
Material Handling for
Biomass Power Generation
Biomass Handling Equipment
Complete Engineered Systems
Pulverized Coal Boiler Conversions
CFB Boiler Feed Systems
1. The NitroLance process. Source: Conco
Intensifier
-160F
LN2
or
supply
Pump
Control valve
-250F
Nozzle
Temp control
Nozzle
may also contain a finned tube steam coil APH immediately after
the forced draft fan. APHs play a critical role in increasing boiler
efficiency-but only when they are properly maintained and kept
clean of airside fouling (see " Air Preheater Seal Upgrades Renew
Plant Efficiency, " p. 54).
LN2 Cleaning Technology
NitroLance, developed by Conco Systems of Verona, Penn., uses
pressurized liquid nitrogen to clean various types of heat exchangers
and industrial surfaces. NitroLance can be used to clean
tube internals with small rotating jets or with larger specialized
manifolds for external heat exchanger surfaces, including delicate
finned heat exchanger tubes.
The NitroLance cleaning system delivers pressurized liquid
nitrogen to the cleaning surface and rapidly removes deposits
through three mechanisms: mechanical pressure, thermal expansion,
and supercooling. The typical NitroLance process flow is
UNITED STATES
UNITED STATES
CANADA
CANADA
SWEDEN
SWEDEN
Silos
Wood Hogs
Disc Screens
Open Storage
Closed Storage
See our Biomass video at www.jeffreyrader.com/videoB
USA: CORPORATE HEADQUARTERS
Jeffrey Rader Corporation
398 Willis Road
Woodruff, SC, USA 29388
Phone: 864.476.7523
Fax: 864.476.7510
CANADA: Montreal, Quebec
Jeffrey Rader Canada
2350 Place Trans-Canadienne
Dorval, Quebec H9P 2X5 Canada
Phone: 514.822.2660
Fax: 514.822.2699
CANADA: Vancouver, BC
Jeffrey Rader Canada
Unit 2, 62 Fawcett Road
Coquitlam, BC V3K 6V5 Canada
Phone: 604.299.0241
Fax: 604.299.1491
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Chain Conveyors
Bucket Elevators
Screw Conveyors
Screw Reclaimers
Pneumatic Conveying
SWEDEN: Stockholm
Jeffrey Rader AB
Domnarvsgatan 11, 163 53 SPÅNGA
Stockholm, Sweden
Phone: +46 8 56 47 57 47
Fax: +46 8 56 47 57 48
For information on how Jeffrey Rader Corporation can solve your Biomass Handling needs, visit us at www.jeffreyrader.com/pow
CIRCLE 30 ON READER SERVICE CARD
18
www.powermag.com
POWER | October 2010

http://csrc http://www.nist.gov/publications/PubsNISTIRs.html#NIST-IR-7628 http://www.tinyurl.com/32d66k4 http://www.jeffreyrader.com/videoB http://www.jeffreyrader.com/pow http://www.powermag.com

POWER October 2010

Table of Contents for the Digital Edition of POWER October 2010