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Title: Session 3: A Status Report on PNL Programs on In-line Chemical and Corrosion Instrumentation and Geothermal Chemistry

Abstract

The direct causes of geothermal plant failures are obvious when they occur--the pipe or heat exchanger has holes in it, the lines are plugged or the injection well will not accept waste brine. The problem that led to the failure is often not obvious, and without any data recording it may not be possible to determine how the problem developed. In many cases these types of failures in hydrothermal power plants have caused multimillion dollar repair costs and extensive down time. In addition to financial losses (over $100,000/day for a 55 MWe plant), these failures cause doubts about the economic viability of geothermal power. In general, the causes of silica, calcite, and sulfide scaling are understood (attached diagrams). Scaling results from operating choices made by the plant designer or operator who has occasionally treated plant design as working with distilled water rather than ''rock soup''. Scale control involves understanding the behavior of minor elements in the brine, especially silica, calcium, and CO{sub 2} and their interactions with brine temperature, pressure and time after production. In the attached diagram the chemistry of two wells at Cerro Prieto is given; one scales up and one does not. The reason is related tomore » the interaction of CO{sub 2} contents and steam separator operating pressures. Uniform corrosion of carbon steel is also understood. Usually corrosion results from acidic (pH < 7) conditions or man-made air intrusions and the presence or absence of protective films on the metal. The monitoring instruments developed and tested with this program include: (1) corrosion rate meters for brine, isobutane and cooling water; (2) electrode less conductivity to monitor brine quality and detect gases; (3) redox meter to detect air intrusions; (4) pH meter to monitor acidity which is related to both corrosion and scaling; (5) suspended particle meter to monitor solids that could plug injection well; (6) CO{sub 2} sensor for brine; and (7) leak detectors for the Heber plant. Plans for FY84 and the instruments still funded are discussed.« less

Authors:
Publication Date:
Research Org.:
Pacific Northwest Lab., Richland, WA (US)
Sponsoring Org.:
U.S. Department of Energy Assistant Secretary, Conservation and Renewable Energy, Division of Geothermal and Hydropower Technologies; Washington, D.C. (US)
OSTI Identifier:
838143
Report Number(s):
CONF-8310177-3
TRN: US200508%%282
Resource Type:
Conference
Resource Relation:
Conference: Proceedings of the Geothermal Program Review II, Washington, DC (US), 10/11/1983--10/13/1983; Other Information: Page range is 76-116; Includes schedules, drawings, graphs; PBD: 1 Dec 1983
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; 36 MATERIALS SCIENCE; 2-METHYLPROPANE; CARBON STEELS; CHEMISTRY; CORROSION; HEAT EXCHANGERS; INJECTION WELLS; LEAK DETECTORS; MONITORS; PH VALUE; POWER PLANTS; SCALE CONTROL; SILICA; STEAM SEPARATORS; SULFIDES; GEOTHERMAL LEGACY

Citation Formats

Shannon, Donald K. Session 3: A Status Report on PNL Programs on In-line Chemical and Corrosion Instrumentation and Geothermal Chemistry. United States: N. p., 1983. Web.
Shannon, Donald K. Session 3: A Status Report on PNL Programs on In-line Chemical and Corrosion Instrumentation and Geothermal Chemistry. United States.
Shannon, Donald K. 1983. "Session 3: A Status Report on PNL Programs on In-line Chemical and Corrosion Instrumentation and Geothermal Chemistry". United States. https://www.osti.gov/servlets/purl/838143.
@article{osti_838143,
title = {Session 3: A Status Report on PNL Programs on In-line Chemical and Corrosion Instrumentation and Geothermal Chemistry},
author = {Shannon, Donald K},
abstractNote = {The direct causes of geothermal plant failures are obvious when they occur--the pipe or heat exchanger has holes in it, the lines are plugged or the injection well will not accept waste brine. The problem that led to the failure is often not obvious, and without any data recording it may not be possible to determine how the problem developed. In many cases these types of failures in hydrothermal power plants have caused multimillion dollar repair costs and extensive down time. In addition to financial losses (over $100,000/day for a 55 MWe plant), these failures cause doubts about the economic viability of geothermal power. In general, the causes of silica, calcite, and sulfide scaling are understood (attached diagrams). Scaling results from operating choices made by the plant designer or operator who has occasionally treated plant design as working with distilled water rather than ''rock soup''. Scale control involves understanding the behavior of minor elements in the brine, especially silica, calcium, and CO{sub 2} and their interactions with brine temperature, pressure and time after production. In the attached diagram the chemistry of two wells at Cerro Prieto is given; one scales up and one does not. The reason is related to the interaction of CO{sub 2} contents and steam separator operating pressures. Uniform corrosion of carbon steel is also understood. Usually corrosion results from acidic (pH < 7) conditions or man-made air intrusions and the presence or absence of protective films on the metal. The monitoring instruments developed and tested with this program include: (1) corrosion rate meters for brine, isobutane and cooling water; (2) electrode less conductivity to monitor brine quality and detect gases; (3) redox meter to detect air intrusions; (4) pH meter to monitor acidity which is related to both corrosion and scaling; (5) suspended particle meter to monitor solids that could plug injection well; (6) CO{sub 2} sensor for brine; and (7) leak detectors for the Heber plant. Plans for FY84 and the instruments still funded are discussed.},
doi = {},
url = {https://www.osti.gov/biblio/838143}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1983},
month = {12}
}

Conference:
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