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• 1. [Image] Development of the high-temperature redox electrode. Interim report ending March 1980

  	The oxidation-reduction (known as redox) electrode was studied in a pH range corresponding to that found in a CO/sub 2/-silicate buffered system at temperatures ranging from 100 to 250/sup 0/C. Oxidizing ...
  	Citation × Citation Citation Abstract Copy Title: Development of the high-temperature redox electrode. Interim report ending March 1980 Author: Danielson, M.J. Year: 1980 The oxidation-reduction (known as redox) electrode was studied in a pH range corresponding to that found in a CO/sub 2/-silicate buffered system at temperatures ranging from 100 to 250/sup 0/C. Oxidizing conditions were created by injecting oxygen; the greatest reducing conditions, by using hydrogen. The sulfur system (H/sub 2/S, HS/sup -/, S/sup 2/) was not examined at this time, but future work will include this system since it is an important component of the geothermal brine. Both a platinized platinum (Pt-Pt) and a bare platinum (Pt-foil) electrode respond to the redox environment. The response does not appear to indicate thermodynamic equilibrium with the chemical environment; instead a mixed potential response is indicated. The difference in potential between a strong oxidizing environment (0.4-ppM O/sub 2/) and a strong reducing environment (0.5-atm H/sub 2/) is typically > 1 volt at all temperatures. The magnitude of this response makes the platinum electrode a suitable sensor for continuous monitoring of the geothermal environment for oxygen intrusions. The platinized platinum redox electrode is superior to the bare platinum electrode; PNL-3377 Title: Development of the high-temperature redox electrode. Interim report ending March 1980 Author: Danielson, M.J. Year: 1980 The oxidation-reduction (known as redox) electrode was studied in a pH range corresponding to that found in a CO/sub 2/-silicate buffered system at temperatures ranging from 100 to 250/sup 0/C. Oxidizing conditions were created by injecting oxygen; the greatest reducing conditions, by using hydrogen. The sulfur system (H/sub 2/S, HS/sup -/, S/sup 2/) was not examined at this time, but future work will include this system since it is an important component of the geothermal brine. Both a platinized platinum (Pt-Pt) and a bare platinum (Pt-foil) electrode respond to the redox environment. The response does not appear to indicate thermodynamic equilibrium with the chemical environment; instead a mixed potential response is indicated. The difference in potential between a strong oxidizing environment (0.4-ppM O/sub 2/) and a strong reducing environment (0.5-atm H/sub 2/) is typically > 1 volt at all temperatures. The magnitude of this response makes the platinum electrode a suitable sensor for continuous monitoring of the geothermal environment for oxygen intrusions. The platinized platinum redox electrode is superior to the bare platinum electrode; PNL-3377 Close

• 2. [Image] Monitoring instrument field experiments at Oregon Institute of Technology

  	The field tests were conducted under reducing and oxidizing conditions. Corrosion rates with zero oxygen were about 1.1 mils per year (mpy) for both copper and steel coupons, which is quite low for carbon ...
  	Citation × Citation Citation Abstract Copy Title: Monitoring instrument field experiments at Oregon Institute of Technology Author: Danielson, M.J. Year: 1980 The field tests were conducted under reducing and oxidizing conditions. Corrosion rates with zero oxygen were about 1.1 mils per year (mpy) for both copper and steel coupons, which is quite low for carbon steel. There was a problem controlling the oxygen level in the oxygenated experiments; however, it was found that corrosion rates increased with the presence of oxygen. Corrosion rates for the steel and copper coupons were 4 and 2 mpy, respectively; copper coupled to cast iron corroded at 8 mpy. Commercial corrosion rate measuring equipment determined the general corrosion rate of carbon steel farily well but overestimated copper corrosion rates. The redox electrode was a very sensitive indicator of the entry of oxygen; PNL-3385 Title: Monitoring instrument field experiments at Oregon Institute of Technology Author: Danielson, M.J. Year: 1980 The field tests were conducted under reducing and oxidizing conditions. Corrosion rates with zero oxygen were about 1.1 mils per year (mpy) for both copper and steel coupons, which is quite low for carbon steel. There was a problem controlling the oxygen level in the oxygenated experiments; however, it was found that corrosion rates increased with the presence of oxygen. Corrosion rates for the steel and copper coupons were 4 and 2 mpy, respectively; copper coupled to cast iron corroded at 8 mpy. Commercial corrosion rate measuring equipment determined the general corrosion rate of carbon steel farily well but overestimated copper corrosion rates. The redox electrode was a very sensitive indicator of the entry of oxygen; PNL-3385 Close