skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Co-production of silica from geothermal fluids

Authors:
; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
889998
Report Number(s):
UCRL-TR-216881
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; 58 GEOSCIENCES; 36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Geothermal Legacy

Citation Formats

Bourcier, W, Johnson, M, Wallace, A, Bruton, C, and Ralph, B. Co-production of silica from geothermal fluids. United States: N. p., 2005. Web. doi:10.2172/889998.
Bourcier, W, Johnson, M, Wallace, A, Bruton, C, & Ralph, B. Co-production of silica from geothermal fluids. United States. doi:10.2172/889998.
Bourcier, W, Johnson, M, Wallace, A, Bruton, C, and Ralph, B. Fri . "Co-production of silica from geothermal fluids". United States. doi:10.2172/889998. https://www.osti.gov/servlets/purl/889998.
@article{osti_889998,
title = {Co-production of silica from geothermal fluids},
author = {Bourcier, W and Johnson, M and Wallace, A and Bruton, C and Ralph, B},
abstractNote = {},
doi = {10.2172/889998},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Nov 04 00:00:00 EST 2005},
month = {Fri Nov 04 00:00:00 EST 2005}
}

Technical Report:

Save / Share:
  • The report summarizes the results of experiments dealing with the problem of removal of waste-silica from spent fluids at the experimental power generating facility in the Puna District of the island of Hawaii. Geothermal discharges from HGP-A represent a mixture of meteoric and seawaters which has reacted at depth with basalts from the Kilauea East Rift Zone under high pressure and temperature. After separation of the steam phase of the geothermal fluid from the liquid phase and a final flashing stage to 100 degrees Celsius and atmospheric pressure, the concentration of the silica increases to approximately 1100 mg/L. This concentrationmore » represents five to six times the solubility of amorphous silica in this temperature range. We have evaluated and successfully developed bench scale techniques utilizing adsorptive bubble flotation for the removal of colloidal silica from the spent brine discharge in the temperature range of 60 to 90 degrees C. The methods employed resulted in recovery of up to 90% of the silica present above its amorphous solubility in the experimental temperature range studied.« less
  • Demonstrate the technical and economic feasibility of small scale power generation from low temperature co-produced fluids. Phase I is to Develop, Design and Test an economically feasible low temperature ORC solution to generate power from lower temperature co-produced geothermal fluids. Phase II &III are to fabricate, test and site a fully operational demonstrator unit on a gold mine working site and operate, remotely monitor and collect data per the DOE recommended data package for one year.
  • A series of experiments was performed to investigate methods of controlling silica in waste geothermal brines produced at the HGP-A Generator Facility. Laboratory testing has shown that the rate of polymerization of silica in the geothermal fluids is highly pH dependent. At brine pH values in excess of 8.5 the suspension of silica polymers flocculated and rapidly precipitated a gelatinous silica mass. Optimum flocculation and precipitation rates were achieved at pH values in the range of 10.5 to 11.5. The addition of transition metal salts to the geothermal fluids similarly increased the rate of polymerization as well as the degreemore » of precipitation of the silica polymer from suspension. A series of experiments performed on the recovered silica solids demonstrated that methanol extraction of the water in the gels followed by critical point drying yielded surface areas in excess of 300 M{sup 2}/g and that treatment of the dried solids with 2 N HCl removed most of the adsorbed impurities in the recovered product. A series of experiments tested the response of the waste brines to mixing with steam condensate and non-condensable gases.The results demonstrated that the addition of condensate and NCG greatly increased the stability of the silica in the geothermal brines. They also indicated that the process could reduce the potential for plugging of reinjection wells receiving waste geothermal fluids from commercial geothermal facilities in Hawaii. Conceptual designs were proposed to apply the gas re-combination approach to the disposal of geothermal waste fluids having a range of chemical compositions. Finally, these designs were applied to the geothermal fluid compositions found at Cerro Prieto, Ahuachapan, and Salton Sea.« less
  • A series of experiments was performed to investigate methods of controlling silica in waste geothermal brines produced at the HGP-A Generator Facility. Laboratory testing has shown that the rate of polymerization of silica in the geothermal fluids is highly pH dependent. At brine pH values in excess of 8.5 the suspension of silica polymers flocculated and rapidly precipitated a gelatinous silica mass. Optimum flocculation and precipitation rates were achieved at pH values in the range of 10.5 to 11.5. The addition of transition metal salts to the geothermal fluids similarly increased the rate of polymerization as well as the degreemore » of precipitation of the silica polymer from suspension. A series of experiments performed on the recovered silica solids demonstrated that methanol extraction of the water in the gels followed by critical point drying yielded surface areas in excess of 300 M{sup 2}/g and that treatment of the dried solids with 2 N HCl removed most of the adsorbed impurities in the recovered product. A series of experiments tested the response of the waste brines to mixing with steam condensate and non-condensable gases.The results demonstrated that the addition of condensate and NCG greatly increased the stability of the silica in the geothermal brines. They also indicated that the process could reduce the potential for plugging of reinjection wells receiving waste geothermal fluids from commercial geothermal facilities in Hawaii. Conceptual designs were proposed to apply the gas re-combination approach to the disposal of geothermal waste fluids having a range of chemical compositions. Finally, these designs were applied to the geothermal fluid compositions found at Cerro Prieto, Ahuachapan, and Salton Sea.« less
  • The two-phase flow system is analyzed as it develops and changes in the well. The product of the study will be a calculational technique to allow the design of geothermal wells in two-phase flow. The overall approach to the project is summarized, and the nature of the two-phase flow problem is discussed. The various elements of the program are presented. (MHR)