Thermal and hydraulic performance tests of a sieve-tray direct-contact heat exchanger vaporizing pure and mixed-hydrocarbon Rankine-cycle working fluids

Technical Report · Mon Aug 01 04:00:00 EDT 1983

DOI:https://doi.org/10.2172/5791707· OSTI ID:5791707

Mines, G L; Demuth, O J; Wiggins, D J

Experiments investigating a sieve-tray direct-contact heat exchanger were conducted at the Raft River Geothermal Test Site in southeastern Idaho using the 60-kW Mobile Heat Cycle Research Facility operating in the thermal loop mode (without a turbine). Isobutane, propane, and several hydrocarbon mixtures were heated and boiled in the direct-contact column, which is approx. 12 in. in diameter and 19-1/2 ft. high, using the energy from a 280/sup 0/F geothermal resource. Using pure fluids, isobutane or propane, the column operated much as intended, with 17 trays used for preheating and one or two accomplishing the boiling. For the pure fluids, individual tray efficiencies were found to be 70% or higher for preheating, and close to 100% for boiling; column pinch points were projected to be well under 1/sup 0/F with some runs reaching values as low as approx. 0.02/sup 0/F. Maximum geofluid throughputs for the isobutane tests corresponded roughly to the terminal rise velocity of a 1/32 in. working fluid droplet in geofluid. Boiling was found to occur in as many as 12 trays for the mixtures having the highest concentrations of the minor component, with overall efficiencies in the boiling section estimated on the order of 25 or 30%. Preheating tray efficiencies appeared to be fairly independent of working fluid, with pinch points ranging from as low as approx. 0.03/sup 0/F for a 0.95 isobutane/0.05 hexane mixture to approx. 2.3/sup 0/F for a 0.85 isobutane/0.05 hexane mixture. Column operation was noticeably less stable for the mixtures than for the pure fluids, with maximum throughputs dropping to as low as 40 to 50% of those for the pure fluids.

• Research Organization: EG and G Idaho, Inc., Idaho Falls (USA)
• DOE Contract Number: AC07-76ID01570
• OSTI ID: 5791707
• Report Number(s): EGG-2253; ON: DE83016428
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150802* -- Geothermal Power Plants-- Power Plant Systems & Components
2-METHYLPROPANE
ALKANES
DIRECT CONTACT HEAT EXCHANGERS
FEDERAL REGION X
FLUIDS
GEOTHERMAL FLUIDS
Geothermal Legacy
HEAT EXCHANGERS
HEXANE
HYDROCARBONS
IDAHO
NORTH AMERICA
ORGANIC COMPOUNDS
PERFORMANCE TESTING
PROPANE
RAFT RIVER VALLEY
RANKINE CYCLE
TESTING
THERMODYNAMIC CYCLES
USA
WORKING FLUIDS