Corrosivity of geothermal brines. Progress report for period ending September 1977. Final report
Results of studies carried out principally during FY 1976 and FY 1977 on the corrosion of ferrous materials in synthetic geothermal brines are summarized. A survey of prior work on electrochemical aspects of the corrosion of iron and carbon steel in chloride solutions is presented, and some of the results of these investigations are summarized. The principal results of the present studies are then recapitulated. Included are measurements of the corrosion potential, corrosion rate, and polarization behavior of iron and carbon steel in deaerated 4 M NaCl over the pH range from 1 to 11 at temperatures up to 100/sup 0/C in a conventional Pyrex electrochemical cell. The effect of pH on hydrolysis, precipitation, and electrochemical reactivity of ferrous and ferric ions in 4 M NaCl at 25/sup 0/C is presented, and implications for plant operation are discussed. Details of a refreshed, stirred titanium autoclave system are described; the system permits electrochemical measurements to be made up to at least 200/sup 0/in corrosive aqueous saline media. The effect of pH (from pH equals 7 to pH equals 2) and temperature (from 25/sup 0/ to 200/sup 0/C) on the corrosion rate of type A212B carbon steel in deaerated 4 M NaCl is described. A relatively simple numerical correlation describes the data over the entire temperature and pH range. The spontaneous corrosion potentials and pitting potentials of types 304 and 316 stainless steel were measured in deaerated 4 M NaCl at pH equals 5 from 25/sup 0/ to 200/sup 0/C, and the data demonstrate the borderline stability of austenitic stainless steel for brine service. Finally, conclusions and recommendations for further studies are presented.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 5101733
- Report Number(s):
- ORNL/TM-6308
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
BRINES
CORROSIVE EFFECTS
CARBON STEELS
CORROSION
ELECTROCHEMICAL CORROSION
GEOTHERMAL FLUIDS
SODIUM CHLORIDES
STEELS
AUSTENITIC STEELS
CHEMICAL REACTION KINETICS
ELECTROCHEMISTRY
HIGH TEMPERATURE
IRON
MEDIUM TEMPERATURE
PH VALUE
PITTING CORROSION
RESEARCH PROGRAMS
STAINLESS STEEL-304
STAINLESS STEEL-316
STAINLESS STEELS
TEMPERATURE EFFECTS
ALKALI METAL COMPOUNDS
ALLOYS
CHEMICAL REACTIONS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
ELEMENTS
FLUIDS
HALIDES
HALOGEN COMPOUNDS
HEAT RESISTING ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
KINETICS
METALS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
REACTION KINETICS
SODIUM COMPOUNDS
TRANSITION ELEMENTS
Geothermal Legacy
150903* - Geothermal Engineering- Corrosion
Scaling & Materials Development
360105 - Metals & Alloys- Corrosion & Erosion