CHARACTERISTICS

Aging equipment makes reliable load-following increasingly risky and inefficient. Plant personnel need tools and methods to pinpoint the causes of failures in boilers. On-line monitoring techniques have been developed to assist plant personnel in analyzing and improving boiler performance. Older boilers can be modified through capacity enhancement, repowering and/or fuel switching to be better positioned to compete in a competitive market.

Aspects of boiler performance that should be evaluated include: whether heat exchanger sections have been removed from service and/or bypassed; presence of boiler heat containment/insulation; the amount of high unburned carbon content in ash; off-design operation; high flue gas exhaust temperature; any acid dew point problems in rear gas passes including air heaters; if desuperheating systems are on manual control or inoperable; any excessive valve leakages; whether there is serious plugging of convective passes with unburned fuel and/or ash; manual control of boilers; and lack of accurate fuel measurement.

SIZE:
Boilers in any size range.

FEATURES:
To optimize boiler performance, actual vs. design operating characteristics can be compared for fuel consumption, efficiency, air flow, distribution losses, boiler controls. Also, comparisons can be made to similar units at other power plants throughout the world.

COST:
Varies significantly, although many improvements involve little or no cost.

CURRENT USAGE:
Considerable use throughout the world.

POTENTIAL USAGE:
Potential benefit from boiler improvements is substantial. For instance, if China's industrial boiler efficiency were raised from the current 65% average to the 80% average attained by developing countries, then energy waste could be reduced by 1.6 quadrillion Btu (1.7 EJ)/year.

ISSUES ASSOCIATED WITH IMPLEMENTING ACTION

• There is a lack of awareness as to the potential benefits of improving boiler conditions.

CLIMATE CHANGE IMPACT

EMISSION EFFECT:
    

CONDITIONS FOR EMISSIONS MITIGATION:

• Total emissions will vary according to the technologies employed, but the U.S. DOE has calculated that making boiler improvements results in an emissions reduction of 116.2 lbs/CO₂ for every million cubic feet (mcf) of gas or methane saved.

EMISSION ESTIMATE:
116.2 lbs/CO₂/mcf of gas or methane saved.² Emissions from coal-fired boilers: N/A.

COST-EFFECTIVENESS:
Costs will vary, but many improvements can be made at little or no cost.

SECONDARY EFFECTS:
Emissions of air pollutants will decrease in proportion to improvements in boiler performance.

RESOURCES

• Schweitzer, J., J. de Wit, M. Koot, and O. Paulsen, 1994, Annual Efficiency of Boilers; Development of an EU Harmonized Method of Calculation, Conference on the Specific Action on Vigorous Energy Efficiency (SAVE) Programme, Florence, (October). http://www.icgti.org/.
• The Electric Power Research Institute is developing technologies and software tools for improved coal-fired boilers; gas/oil-fired boilers, as well as boiler upgrades and diagnostic and life assessment tools. http://www.epri.com/gg/fossil/
• The 1999 First Quarter issue of the CADDET Energy Efficiency Newsletter focuses on boilers and burners, including information on technological advances and performance improvements. The newsletter is available at http://www.caddet-ee.org/991_co.htm, or by requesting a copy from CADDET.
• The Association of Energy Engineers presents workshops on optimizing boiler performance. http://www.aeecenter.org.

CONTACTS

Association of Energy Engineers
Atlanta, Georgia
Tel: (770) 447-5083
Fax: (770) 446-3969
http://www.aeecenter.org

CADDET Energy Efficiency
Sittard, The Netherlands
Tel: +31-46-420-2224
Fax: +31-46-451-0389
caddet@caddet-ee.org
http://www.caddet-ee.org

Electric Power Research Institute
Tony Armor
Fossil & Renewables Generation
Tel: (650) 855-2961
Fax: (650) 855-2954
AArmor@epri.com