A method for recovering energy from a geothermal reservoir in which brine from the reservoir is first employed to heat an immiscible fluid, such as a hydrocarbon in direct heat exchange and the heated hydrocarbon is then utilized in direct heat exchange to heat a second fluid, such as boiler feed water, to raise steam as the actual working fluid in the power cycle.
A method for producing mechanical energy from geothermal fluids in which a heat transfer fluid (HTF) is heated by direct contact with the hot geothermal fluids, thereby partially cooling the geothermal fluids. A working fluid is heated by direct contact with the partially cooled geothermal fluid and is heated further by indirect heat exchange with the hot HTF. The heated working fluid is utilized in a heat engine for the production of mechanical energy.
A small power plant utilizing waste heat wherein: an intermediate heat transfer medium being thermally stable and capable of lubricating bearings is interposed between a heat source and a turbine operating medium; heat of said intermediate heat transfer medium is taken off through a direct contact heat exchanger to change said turbine operating medium in phase from a liquid state to a gaseous state; and a portion of said intermediate heat transfer medium is supplied as the lubricant for the bearings of the turbine and generator.
A process and system for recovery of energy from geothermal brines or other hot aqueous solutions of a non-volatile solute, by direct contact heat transfer using staged evaporator-condenser units operating with a low boiling water-immiscible liquid hydrocarbon. Each stage comprises a closed vessel divided into two compartments, an evaporator and a condenser, by a bubble cap tray similar in construction to those used in distillation. Hot geothermal brine or other hot aqueous liuqid is introduced into the liquid hydrocarbon contained in the lower compartment of each stage, causing boiling of the hydrocarbon at a temperature difference of 2.degree.-4.degree. F. Hydrocarbon vapors pass from the evaporator compartment through the bubble caps to the upper condenser compartment where they are condensed in contact with a cooler water stream, and the condensed hydrocarbon is returned to the lower compartment. The heated water stream under substantial pressure is fed to an expander or turbine to produce work, and the expander discharge, after cooling and condensation of any steam therein, is reintroduced into the evaporator compartments of the staged units. Such recycled water, together with make-up water is introduced as feed into the condenser compartment of the last stage and passes into the respective condenser compartments of each of the preceding stages, and is further heated in each stage, and the hot brine, or the like, introduced into the evaporator compartment of the first stage is passed through the evaporator compartments of each successive stage and is further cooled in each successive stage, and is finally passed to waste.
A low boiling point medium power plant in which heated waste gas, such as furnace gas, geothermic steam, etc., is used as a heat source for heating an intermediate thermal medium by means of an indirect heat exchanger, and the intermediate thermal medium is used as a heat source for heating a turbine driving low boiling point medium by means of a direct heat exchanger. The indirect heat exchanger and the direct heat exchanger are rendered into a unitary structure and contained in a sealed housing together with a turbine, a generator and a condenser, whereby a compact overall size can be obtained in a low boiling point medium power plant.
4315402 - Heat transfer process and system - Owned by Occidental Research Corporation (Irvine, CA) [*] Notice:The portion of the term of this patent subsequent to December 9, 1997 has been disclaimed.
Direct contact heat transfer process and system for recovery of energy from geothermal brines or other hot aqueous solutions of a non-volatile solute, or for desalination, using staged evaporator-condenser units operating with a low boiling water-immiscible liquid hydrocarbon. Each stage comprises a closed vessel divided into two compartments, an evaporator and a condenser, by a bubble cap tray similar in construction to those used in distillation. In one embodiment, hot geothermal brine or other hot aqueous liquid is introduced into the liquid hydrocarbon contained in the lower compartment of each stage, causing boiling of the hydrocarbon. Hydrocarbon vapors pass from the evaporator compartment through the bubble caps to the upper condenser compartment where they are condensed in contact with a cooler water stream. The heated water stream under substantial pressure is fed to an expander or turbine to produce work. In another embodiment using the same staged heat transfer system for desalination, relatively hot fresh water is introduced into the liquid hydrocarbon contained in the lower compartment of each stage, causing boiling of the hydrocarbon, and the hydrocarbon vapors pass from the evaporator compartment to the upper condenser compartment where they are condensed in contact with a colder saline stream. The heated saline stream is flash evaporated and the vapors are condensed with a portion of this condensed stream taken off as product.
