Water, steam, and turbine deposit chemistries in phosphate-treated drum boiler units: Final report

Technical Report · Sat Aug 01 04:00:00 EDT 1987

OSTI ID:6131990

Jonas, O

This report presents results obtained in several EPRI projects under RP1886, The Effect of Phosphate on Turbine Components. The main thrust of this project was to investigate the possible role that the phosphate boiler water chemical treatment has on the integrity of steam turbine blades. Only drum boiler units using phosphate boiler water treatment are included in this study. Information on concentration and transport of chemical impurities and sodium phosphate around drum boiler cycles was collected and correlated with chemical composition of low pressure (LP) turbine deposits collected after the water and steam sampling. Correlation of results of turbine inspections (reported as blade and disc cracking) revealed that turbines which did not have cracking in LP turbines had a higher concentration of phosphate in deposits and higher carry-over and turbines with HP blade cracking had a high concentration of sodium in deposits. The effects of water and steam chemistry on blade corrosion were also assessed from the deposit chemistry combined with corrosion fatigue and other corrosion data on turbine materials reported elsewhere. About 50% of the turbines for which deposits were collected had chloride and sulfate in deposits at concentrations above 0.25 wt %, which can potentially be corrosive. A comparison of concentrations of impurities to the limits recommended in the EPRI Interim Consensus Guidelines (6) is also presented. It shows that the limits for chloride and sulfate for boiler water and steam can easily be met, but that the congruent or coordinated phosphate boiler water treatment control is difficult to maintain. 34 refs.

• Research Organization: Jonas, Inc., Wilmington, DE (USA); Electric Power Research Inst., Palo Alto, CA (USA)
• OSTI ID: 6131990
• Report Number(s): EPRI-CS-5275; ON: TI87920540
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
200101* -- Fossil-Fueled Power Plants-- Cooling & Heat Transfer Equipment & Systems
BOILERS
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
CORRELATIONS
CORROSION
CRACKING
DECOMPOSITION
DEPOSITS
FEEDWATER
FOSSIL-FUEL POWER PLANTS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
MACHINERY
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
POWER PLANTS
PYROLYSIS
STEAM
STEAM TURBINES
THERMAL POWER PLANTS
THERMOCHEMICAL PROCESSES
TURBINE BLADES
TURBINES
TURBOMACHINERY
WATER
WATER CHEMISTRY
WATER TREATMENT