Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Solubility of selected secondary fluids for use in direct contact geothermal power cycles. [R-113, R-114, isobutane, and pentane]

Technical Report ·
OSTI ID:7099580
The use of a direct contact binary power cycle, in connection with a geothermal resource, makes it necessary to consider the solubility of the secondary fluid within the geothermal brine, at the outlet of the power plant. Four possible fluids for use in a direct contact binary cycle were considered. They were: pentane, isobutane, R-113 (trichloro-trifluoro ethane), and R-114 (dichloro-tetrafluoro ethane). The solubility was determined, using gas chromatography, for the temperature range 25 to 95/sup 0/C and also for sodium chloride concentrations ranging from 0 to 25 weight percent. The solubilities of these four fluids were compared as a function of various binary cycle parameters. It was found that isobutane has the lowest absolute solubility, if all the fluids are at the same pressure. Pentane is only slightly more soluble than isobutane, for the same pressure. It was found that pentane is less soluble than the other three fluids, if all four fluids are allowed to expand to their partial pressure for a given temperature. It was also found that pentane was the least expensive of the four fluids to operate at a given condenser temperature and brine outlet temperature.
Research Organization:
Utah Univ., Salt Lake City (USA). Dept. of Mechanical Engineering
OSTI ID:
7099580
Report Number(s):
IDO-1549-6
Country of Publication:
United States
Language:
English