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Title: On-line tests of organic additives for the inhibition of the precipitation of silica from hypersaline geothermal brine II. Tests of nitrogen-containing compounds, silanes, and additional ethoxylated compounds

Technical Report ·
DOI:https://doi.org/10.2172/6048498· OSTI ID:6048498

Several new classes of organic compounds have been screened as potential geothermal scale control agents by examining their effect on the precipitation of silica from Magmamax No. 1 brine. The substances were tested using the Lawrence Livermore Laboratory Brine Treatment Test System at the Niland, California, Test Site. Solutions of the test substances were injected into flowing brine at 210{sup 0}C, the brine was flashed to 125{sup 0}C, and then the kinetics of solids and silica precipitation from effluent brine held at 90{sup 0}C were measured. Three new types of compounds were shown to have activity as precipitation inhibitors: polyethylene imines, polyethyloxazalines, and quaternary ammonium compounds containing polyoxyethylene. Among the latter, Ethoquad 18/25, which is methyl-polyoxyethylene(15) octadecylammonium chloride, is the leading candidate antiscalant. It is a more powerful inhibitor of silica precipitation than the pure polyoxyethylene polymers, and it apparently has no high temperature solubility limitations. Measurements were made of the concentrations of monomeric silica and the effect of addition of inhibitor at various points in the Brine Treatment Test System. Five different silane compounds showed no activity toward silica.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6048498
Report Number(s):
UCID-18195
Country of Publication:
United States
Language:
English