Bechtel International Corporation

Electric Power Research Institute Incorporated

Bechtel Group, Inc.

Bechtel Power Corporation

Leon Awerbuch

Alfred N Rogers

Jack Z Abrams

August D Benz

Sherman C May

Charles T Draney

Victor Van Der Mast

Stanley J Zaczek

John Haidinger

Victor C Van Der Mast

David P McGrath

Efficient removal of sulfur dioxide from a flue gas stream is achieved in a scrubber using a recirculating aqueous stream containing magnesium hydroxide and magnesium sulfite which together act as SO.sub.2 absorbents. Magnesium sulfite is derived from magnesium hydroxide, which is the product of a reaction between soluble magnesium from the seawater and calcium hydroxide added to the scrubbing system. Magnesium sulfite and bisulfite are oxidized to magnesium sulfate by the introduction of air. Magnesium sulfate is converted back to magnesium hydroxide by reaction with additional calcium hydroxide, with gypsum as a by-product. Gypsum is soluble in large amounts of seawater and may be returned to the ocean without adverse environmental impact.

Use of seawater in flue gas desulfurization

Improved apparatus and method in which brine of the geothermal and geopressured types is directed into one or more flash-crystallizer-separator units from a geothermal well. Such brine is separated into a gaseous fraction, a liquid fraction and a solids fraction. The gaseous fraction is used to provide useful work, such as driving a turbine, while the liquid and solids fractions are treated to remove the mineral values therefrom. The liquid fraction, following the mineral recovery therefrom, is directed back into the earth through an injection well. An important aspect of the invention is the injection of chemicals into one or more of the process vessels of the apparatus of the present invention. This causes additional mineral growth, such as the growth of heavy metal sulfide, in the brine. This is achieved by injecting sulfide ions into the brine, preferably in the form of sodium sulfide. The resulting brine slurry formed in the vessels can be sent to a thickener and then to a filter press for dewatering. The resulting filter cake contains the mineral values in the form of heavy metals, primarily lead, silver and zinc, and the filter cake can be sold to a smelter for extraction of the metals or the metals can be extracted on site.

Apparatus and method for mineral recovery from geothermal and

Apparatus and a method for separating gases and vapors from a geopressure or hydropressured brine without allowing precipitation of scale deposits on the walls of vessels and pipes. The apparatus includes a reactor having an inlet pipe provided with a Venturi throat and an expansion nozzle coupled with the throat to depressurize the brine to cause separation of the gases and vapors from the liquid and solid fractions of the brine. The gases and vapors travel out of the reactor through a central pipe extending downwardly and through the reactor. The brine in the form of a slurry gravitates in the reactor toward a first outlet pipe while clarified brine rises past an internal baffle and leaves the reactor through a second outlet pipe. A third pipe coupled to the reactor near the lower end thereof draws slurry into the Venturi throat by suction to cause mixing of incoming brine and slurry so that the solids in the slurry provide nuclei for crystallization to prevent scale deposit on the walls of adjacent structure. A part of the clarified brine is taken from the second outlet pipe and pumped to the bottom of the reactor to elutriate the finer crystals in the slurry in the reactor.

Separating gases from geopressured or hydropressured brine

Apparatus and a method for separating gases and vapors from a geopressure or hydropressured brine without allowing precipitation of scale deposits on the walls of vessels and pipes. The apparatus includes a reactor having an inlet pipe provided with a Venturi throat and an expansion nozzle coupled with the throat to depressurize the brine to cause separation of the gases and vapors from the liquid and solid fractions of the brine. The gases and vapors travel out of the reactor through a central pipe extending downwardly and through the reactor. The brine in the form of a slurry gravitates in the reactor toward a first outlet pipe while clarified brine rises past in internal baffle and leaves the reactor through a second outlet pipe. A third pipe coupled to the reactor near the lower end thereof draws slurry into the Venturi throat by suction to cause mixing of incoming brine and slurry so that the solids in the slurry provide nuclei for crystallization to prevent scale deposit on the walls of adjacent structure. A part of the clarified brine is taken from the second outlet pipe and pumped to the bottom of the reactor to elutriate the finer crystals in the slurry in the reactor.

Gas separating-crystallizer

Apparatus and method for handling geothermal brine containing high non-condensible gas concentrations. The brine is directed into a pre-flash chamber where a vapor fraction is separated from a liquid fraction, the vapor fraction including steam and a non-condensible gas. The vapor fraction is directed into and through a reboiler in countercurrent flow relationship to a condensate. This action causes the steam of the vapor fraction to be stripped from the non-condensible gas and also causes the condensate to be heated by the steam. The non-condensible gas flows out of the reboiler to a gas expander collection station, or to the atmosphere while the condensate flows to a flash chamber where it flashes to obtain clean steam for driving a work producing apparatus, such as a turbine. The condensate from the flash chamber is returned by a pump to the condensate inlet of the reboiler to form a closed system.

Geothermal reboiler apparatus and method

An improved method and apparatus for disposal of spent brine after the energy and mineral values have been extracted from the brine, taking advantage of the basic thermodynamic properties of suspended and dissolved scalars in geothermal fluids. A controlled portion of the extracted steam energy value from the brine is used to reheat spent brine before reinjection. The spent brine thereby ceases to be supersaturated with respect to solids, and stabilized silicas therein do not precipitate out and deposit themselves upon the entrance of a reinjection well. Means for using a controlled portion of the extracted steam energy from a plurality of serially connected flasher reactors is shown.

Silica stabilization and reinjection for geothermal method and apparatus

Apparatus and method for improved circulation and solid fraction removal in geothermal energy recovery. Geothermal fluid is directed into an integrated flasher-crystallizer-separator reactor, used in one or more flash stages, for substantially continuous recovery of the energy values of the incoming geothermal fluid while simultaneously allowing for growth of crystals and separation of the liquid fraction of fluid from the solid fraction. The geothermal fluid flows through a vertical Venturi tube, thereby creating a low pressure area near the entrance to the tube. The low pressure area draws in the liquid containing seed crystals from the surrounding bath, thereby presenting the incoming brine with a large population of seed crystals and also promoting vigorous agitation in the reactor without the use of mechanical agitators. In a second aspect of the invention, a small stream of partially flashed fluid is reintroduced to the reactor at a solids disengaging section, sweeping smaller crystals therein back into the agitated brine for use as seed crystals in the reactor. In a third aspect of the invention, a downstream reactor has larger and slower clarification means than upstream reactor for efficient clarification of the liquid fraction before reinjection into a disposal well.

Venturi flash circulator for geothermal apparatus

Apparatus and method for using the vapor fraction of geothermal or geopressured fluid to produce useful work and for using the solid fraction of the fluid for producing minerals of commercial value while providing protection from scaling. The fluid is directed into a first chamber in which the fluid flashes to generate the vapor fraction. A circulatory flow through the first chamber occurs as a result of the flashing of the vapor fraction, causing the vapor fraction to separate from the solid and liquid fractions and allowing the vapor fraction to pass to a fluid-actuated, work-producing apparatus. The solid and liquid fractions gravitate into a second chamber adjacent to the first chamber and extending below the first chamber. The second chamber permits at least a portion of the liquid fraction to separate from the solid fraction by clarification. Crystal growth continuously occurs in the first and second chambers as the circulation of the fluid continues through the first chamber. When the crystals become large enough, they gravitate to the bottom of the second chamber and can be removed therefrom. The separated liquid fraction of the fluid can be directed to a point of disposal or through one or more additional reactor stages to recover the remaining energy and mineral values therefrom. Several embodiments of the apparatus as disclosed.

Apparatus and method for energy production and mineral recovery from

Apparatus and a method of adding CO.sub.2 to softened water flowing through a series of interconnected flash chambers after the softened water has been directed out of a settler. The inlet of the settler receives preheated hard water after the hard water has passed through a series of interconnected preheating chambers, there being a preheating chamber for each flash chamber, respectively. Each preheating chamber and the corresponding flash chamber comprise a stage of a multi-stage water softening system, the preheating and flash chambers of each stage being separated by a partition defining an opening near the top portion of the stage to place the respective first and second chambers of each stage in fluid communication with each other and to allow flashed, heated water vapor from the flash chamber to pass into direct, admixing contact with cooler, hard water sprayed into the preheating chamber to preheat the hard water. As the hard water is preheated by the flashed water vapor in each preheating chamber, CO.sub.2 is evolved and then directed into a predetermined flash chamber, such as the flash chamber of the next downstream stage with reference to the direction of flow of softened water through the stages. The CO.sub.2 stabilizes the softened water and reduces its pH. The CO.sub.2 evolved from the settler is also directed into a flash chamber, such as the upstream flash chamber for stabilization and pH lowering purposes.

Stabilization of softened water with self-generated CO.sub.2

A multi-effect system for using the heat, water and solids content of geothermal brine to produce useful work, fresh product water and inorganic salts. A flash separator receives brine from a geothermal well and provides the initial steam forming the heat source for the brine flowing through a first effect of the system. The system has a number of effects in series with each effect having means for generating steam from the brine flowing through it, and using the generated steam to provide the heat source for the next adjacent effect. Steam from each effect is also moved in heat exchange relationship to a binary fluid in a closed loop containing a gas turbine so that the binary fluid can be heated sufficiently to drive the turbine, the latter, in turn, being coupled to a work-producing apparatus, such as a generator. In one form of the invention, the steam to heat the binary fluid is the uncondensed part of the steam used as a heat source for each effect. In another form of the invention, this steam is part of the steam generated in each effect. Condensate formed in each effect from the steam received thereby is transferred to the next adjacent effect and, from the last effect, the condensate is drawn off as fresh product water. Brine blowdown removed from one or more of the effects provides the source of inorganic salts. As disclosed herein, the effects are vertical tube evaporators.

Energy transfer apparatus and method using geothermal brine

A system using a number of flash chambers for converting the heat energy of geothermal brine to useful work. The system uses steam from flashed brine to vaporize a portion of distilled water or distillate in one or more heat exchangers to produce steam to drive a turbine which, in turn, operates a generator or the like to produce useful work. Before the distillate reaches the heat exchanger, it is preheated as it flows through a series of flash chambers in countercurrent relationship to the flow of geothermal brine therethrough. The brine flashes in each flash chamber and the flashed vapor mixes with the distillate flowing through the flash chamber to pre-heat the distillate. The heat energy of the unvaporized part of the distillate in the heat exchanger can form additional steam which is also supplied to the turbine. The heat content of the unflashed part of the distillate can be used in several ways to heat a working fluid in a closed loop containing a second turbine. The unflashed distillate can either be directed through a second heat exchanger which also receives a second working fluid so as to heat the latter, or the unflashed distillate can be flashed and the flashed vapor is placed in heat exchange relationship to the working fluid. Condensate formed in the latter case can be used as fresh product water. Inorganic salts from the brine can also be derived from the system.

Apparatus and method of geothermal energy conversion

A system for softening of water in a manner to minimize heat requirements in the water softener unit of the system. Flashed water vapor from a flash box coupled to the downstream end of the softener unit is used to preheat incoming hard feed water by directly contacting the feed water in respective preheating chambers upstream of the softener unit. The system is suitable for use in a distillation plant to produce potable water.

Thermal softening and distillation by regenerative method

A system and method for utilizing the heat energy of the effluent from a geothermal well. The system includes a surface evaporator which allows a preheated distillate, freed of impurities, to be vaporized by the heat energy of the steam and/or brine from the geothermal well. The resulting vapor is used to drive a power unit such as a multi-stage turbine. The vapor exhausted from the power unit is condensed by any of a number of conventional means. A portion of the condensate is then recycled through the system, wherein it becomes the direct contact condensing medium for the vapor produced by flashing hot geothermal brine in a multi-stage flash evaporator through which the brine and the condensate are passing countercurrently. The vapor thus condensed augments the aforesaid recycled condensate and, together, they constitute the aforementioned distillate entering the surface evaporator and carrying with it the heat energy extracted from the brine in the flash evaporator. The remainder of the condensate from the condenser may be withdrawn from the system and constitutes a product resulting from the practice of the desalination process of the invention. Residual brine is carried off from the multi-stage flash evaporator and contains retrievable salts and other valuable minerals.

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San Francisco, CA, United States of America

Leon Awerbuch