Thermal and hydraulic performance of a sieve tray direct contact heat exchanger

Experiments investigating the thermal and hydraulic performance of a sieve tray direct contact heat exchanger (DCHX) were conducted using a 275/sup 0/ geothermal fluid as an energy source and different hydrocarbons as working fluids. The baseline performance tests with the direct contact unit were conducted with isobutane. The thermal performance of the unit met or exceeded the design goals for individual tray thermal efficiencies and pinch points. Hydraulically the column operated near recommended design fluid velocities. Following the completion of these tests, the DCHX was operated with different mixtures of hydrocarbon working fluids. Different combinations of the isobutane/hexane family were tested followed by a series with propane/isopentane fluids. The testing conducted with the direct contact unit showed that the sieve tray column is a very efficient heat exchange device although some degradation in boiling tray efficiency and column throughput were noted when mixtures were used.