Process and system for recovery of energy from geothermal brines and other water containing or hot water sources, which comprises direct contact heat exchange between the brine or hot water, and a working fluid, e.g. n-butane, in a heat transfer column, the heat transfer column being operated in the subcritical pressure region of the working fluid, preferably close to or approaching the apex of the saturated vapor curve for such working fluid on the Mollier enthalpy-entropy diagram for such fluid. The heated working fluid exiting the top of the heat transfer column is expanded through an expander to produce work. The discharge from the expander is cooled to condense working fluid which is separated in an accumulator, from condensed water vapor present in the working fluid, and the condensed working fluid is pressurized and fed back to the heat transfer column. Water from the accumulator can be fed to an H.sub.2 S removal system where good quality water can be recovered. Cooled brine or water from the bottom of the heat transfer column and water from the accumulator are fed to a flashing device such as a flash drum, and the working fluid flashed off is compressed and returned to the cooler at the expander discharge, for condensation and recovery. Also, entrained liquid phase working fluid can be separated from the cooled brine or water prior to flashing, and returned to the system. Uncondensible gases plus some working fluid losses are vented from the accumulator, and preferably the system can be operated under conditions to vent a minimum of uncondensible gases from the accumulator, and thereby reduce working fluid losses, Any accumulator vent gas can be fed to the H.sub.2 S removal system.

Process and system for recovery of energy from geothermal brines and other hot water sources, which comprises direct contact heat exchange between the brine or hot water, and a hydrocarbon working fluid, e.g. n-butane, in a heat transfer column, the heat transfer column being operated at or above the critical pressure of the working fluid, and the hot brine or hot water feed being at a temperature at or above the critical temperature of the working fluid. The heated working fluid exiting the top of the heat transfer column is expanded through an expander to produce work. The discharge from the expander is cooled to condense working fluid which is separated in an accumulator, from condensed water vapor present in the working fluid, and the condensed working fluid is pressurized and fed back to the heat transfer column. Water from the accumulator can be fed to an H.sub.2 S removal system where good quality water can be recovered. Cooled brine or water from the bottom of the heat transfer column is fed to a flashing device such as a flash drum and the working fluid flashed off is compressed and returned to the cooler at the expander discharge, for condensation and recovery. Such cooled brine or water can be fed to one or more liquid expanders prior to flashing to produce additional work. Also, entrained liquid phase working fluid can be separated from the cooled brine or water prior to flashing, and returned to the system. Uncondensible gases plus some working fluid losses are vented from the accumulator and preferably the system can be operated under conditions to vent a minimum of uncondensible gas from the accumulator, and thereby reduce working fluid losses. Any accumulator vent gas can be fed to the H.sub.2 S removal system. Cold brine or water is discharged from the flash drum. Alternatively, if the flash drum is employed as a stripping column, a portion of the vent gas from the accumulator can be recycled as stripping gas to the stripping column for recovery of working fluids therefrom. Preferably, the uncondensible gases are removed from the feed brine or hot water prior to entry into the heat transfer column, such degassing preferably being carried out by a simple flash followed by energy recovery in a steam expander. The steam from the steam expander can be fed to the H.sub.2 S removal system.

Disclosed is an apparatus for continuous measurement of the proportion of relatively non-condensable gases in a flow of mixed gases such as geothermal steam. The apparatus is an open system which detects the proportion of relatively non-condensable gases in a sample flow continuously. The sample flow is condensed and supplied in a tube which conditions the sample flow to consist of a series of segments of condensate and segments of uncondensed gases. The sensor senses the relative volume of the condensate and the uncondensed gases. The data processing means receives the output of the sensor and calculates the proportion of non-condensable gases in the flow of mixed gases. In the preferred embodiment, the sensor optically detects the ratio of the volume of the condensate to the volume of uncondensed gases. Also disclosed are applications of the apparatus for supplying the continuous measurement of the proportion of non-condensable gases in a flow of mixed gases for use in the monitoring of geothermal steam supplied to an end user.

Geothermally heated fluid is supplied to a nozzle of the first stage of a hydraulic turbine. The water constituent of the geothermally heated fluid is directed by the nozzle against the wheel of the hydraulic turbine to cause the wheel to rotate. A first generator is coupled to the wheel whereby rotation of the wheel results in the generation of electricity. A portion of the geothermally heated fluid passing through the nozzle flashes to a vapor phase. The vapor is delivered to the first stage of a vapor driven turbine. The vapor passes through the wheel of the turbine which results in rotation thereof. A second generator is coupled to the wheel of the vapor driven turbine whereby rotation of the wheel results in additional generation of electricity.

A power producing system includes a source of geothermally heated fluid having inorganic salts dissolved therein. The fluid is directed through a first direct contact heat exchanger in heat transfer relation with a working fluid of a type insoluble in a liquid including inorganic salts. The vaporous working fluid thus produced is expanded through a prime mover and then directed through a second direct contact heat exchanger. The vaporous fluid is condensed in said second direct contact heat exchanger by passing in heat transfer relation with a relatively cold heat exchange medium comprising a liquid brine solution. The condensed working fluid is thereafter returned to the first direct contact heat exchanger for repeated reuse in the cycle. Inorganic salts are mixed with either the geothermal heated fluid or the relatively cold heat exchange medium to maintain the percentage by weight of inorganic salt in each of the fluids above a predetermined value to prevent the working fluid from being absorbed therein.