Guidelines for the prevention of economizer inlet header cracking in fossil boilers

Technical Report · Wed Nov 01 04:00:00 EST 1989

OSTI ID:5382492

Stephenson, G G ^[1]

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1. Ontario Hydro, Toronto, ON (Canada)

A large number of utilities are experiencing cracking of the inlet headers of economizers in fossil boilers. The first evidence of its occurrence is generally a pinhole leak in the header/stub tube attachment weld. Inspection of the tube bore hole in the header will reveal numerous longitudinally oriented cracks which may propagate across the ID ligament spacing between bore holes. The mechanism is associated with the introduction of relatively cold feedwater to the hot header during start-up and off-line drum top-up periods producing thermal fatigue damage. State-of-the-art techniques for the prevention and control of economizer inlet headers have been identified from utilities' and boiler manufacturers' experience. This data has been used to produce a comprehensive and practical guideline for utility use. The guideline has been set-up to lead the user through a step-by-step process, indicating what information needs to be obtained at each step, how it should be analyzed, and the conclusions to draw. Inspection techniques to determine the extent of the damage and temperature monitoring tests to correlate the damage with operating parameters are important first steps in the analysis. Operating procedure modifications to reduce thermal stresses are discussed which will alleviate the problem. 20 refs., 53 figs.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (USA); Ontario Hydro, Toronto, ON (Canada)
• Sponsoring Organization: EPRI
• OSTI ID: 5382492
• Report Number(s): EPRI-GS-5949
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
200104* -- Fossil-Fueled Power Plants-- Components
ALLOYS
AVAILABILITY
BOILERS
COMMINUTION
CRACK PROPAGATION
DIAGRAMS
DOCUMENT TYPES
ECONOMIZERS
FATIGUE
FEEDWATER
FERRITIC STEELS
FLOWSHEETS
FOSSIL-FUEL POWER PLANTS
FRACTURING
HYDROGEN COMPOUNDS
INSPECTION
IRON ALLOYS
IRON BASE ALLOYS
MECHANICAL PROPERTIES
MONITORING
OXYGEN COMPOUNDS
POWER PLANTS
PROGRESS REPORT
STEELS
TEMPERATURE MONITORING
THERMAL FATIGUE
THERMAL POWER PLANTS
TUBES
WATER