Development of a high temperature pH electrode for geothermal fluids
This work demonstrates the applicability of a stabilized zirconia pH sensor to high temperature measurements on brines containing as much as 20 weight percent NaCl and 100 ppm hydrogen sulfide. Throughout the program, stable operation was achieved, and measured pH values from 3 to 9 were in good agreement with calculated values. Differences were generally less than 0.5 pH unit at 285/sup 0/C, and it is not yet certain whether the discrepancies are associated with the measured or calculated values of the pH. Two sensors were operated at 285/sup 0/C for periods of 11 days, and one was employed in successive tests for a total of 37 days. At the end of this period, the sensor was still satisfactory, and it was forwarded to the sponsoring laboratory, PNL, for further tests. Although most of the work was performed at 285/sup 0/C, a limited amount of testing was done at lower temperatures: 95/sup 0/, 150/sup 0/, and 225/sup 0/C. Sensors prepared from in-house tubes and from tubes obtained from an outside supplier performed well at 95/sup 0/C for extended periods, in spite of earlier difficulties with the standard ceramic at this temperature. There is still, however, some uncertainty concerning the adequacy of our seals, particularly in cycling between 285/sup 0/C and lower temperatures. In a brief experiment, one sensor was operated satisfactorily at 285/sup 0/C and 5000 psi pressure. (Normal operation was at 1200 psi.)
- Research Organization:
- General Electric Company, Corporate Research and Development Center, Schenectady, New York
- OSTI ID:
- 6562379
- Journal Information:
- J. Electrochem. Soc.; (United States), Vol. 131:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
47 OTHER INSTRUMENTATION
ELECTRODES
DESIGN
PERFORMANCE
GEOTHERMAL FLUIDS
TEMPERATURE MEASUREMENT
HIGH TEMPERATURE
HYDROGEN SULFIDES
MEASURING INSTRUMENTS
PH VALUE
SODIUM CHLORIDES
ZIRCONIUM
ALKALI METAL COMPOUNDS
CHALCOGENIDES
CHLORIDES
CHLORINE COMPOUNDS
ELEMENTS
FLUIDS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
METALS
SODIUM COMPOUNDS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENTS
150301* - Geothermal Exploration & Exploration Technology- Geophysical Techniques & Surveys
440300 - Miscellaneous Instruments- (-1989)