Abstract: In a geothermal electrical power generating plant of the type employing one or more flash crystallizers and one or more reactor clarifiers for processing a large quantity of particulate silica that precipitates out of the hot geothermal brine as thermal energy is extracted during power production, method and apparatus for continuously separating toxic particulate scale out of the nontoxic particulate silica. A portion of the clarifier sludge underflow is treated to cause vertical separation of the scale particles from the silica particles by means of a continuous vertical countercurrent decantation process in which a liquid slurry of the silica and scale particles is flowed upwardly at a velocity greater than the terminal settling velocity of the silica and less than the terminal settling velocity of the scale.

Abstract: In a geothermal electric power generating plant of the type wherein a flow stream of hot geothermal brine from a production well is partially flashed to steam for turbine motive power, system and method for removing most of the entrained noncondensable gas content of the brine proximate the high temperature end of the plant, while at the same time recovering most of the heat energy from steam necessarily released with the noncondensable gases. The noncondensable gases such as carbon dioxide, hydrogen sulfide, ammonia, and boric acid, together with a substantial amount of high pressure, high temperature steam, are separated from the brine flow stream before its entry into conventional flash portions of the plant. A heat exchange system is employed to transfer heat from the separated steam and its condensate and from the separated gases to substantially pure turbine exhaust water condensate so as to boil the pure water for turbine motive steam.

Abstract: In a geothermal electric power generating plant of the type wherein a flow stream of hot geothermal brine is partially flashed to steam for turbine motive power, a system and method for removing entrained brine droplets and particulates from the flashed steam so as to protect turbine components from being fouled and damaged, and also to protect flash vessel demisters from being clogged and corroded. The hot geothermal brine is flashed to steam in flash crystallizer vessels, each of which receives the hot geothermal brine flow stream in its lower portion and has a baffle tray system in its upper portion through which the flashed steam passes. The baffle tray system provides a sinuous path for the flashed steam which produces a series of centripetal accelerations of the steam so as to centrifugally separate the entrained materials from the steam onto surface portions of the baffle tray system and wall portions of the upper portion of the flash crystallizer vessel.

Abstract: Apparatus and method for minimizing silica scaling in steam flash vessels employed in a geothermal power plant energized by steam flashed from high temperature geothermal brine derived from a source such as the Salton Sea Geothermal Field or the Brawley Geothermal Field where the brine is substantially saturated with dissolved silica. The silica is preferentially precipitated upon silica seeds that are introduced into one or more flash crystallizer steam separators. The seeded brine is recirculated through each flash crystallizer a plurality of times under thermal power provided by the effects of flashing the incoming brine into an external draft tube so as to provide a sufficient residency time of the seeded brine in the flash crystallizer for the silica solution, which has become supersaturated because of the temperature reduction associated with the flashing, to be precipitated down to approximately saturation.

Abstract: Highly saline geothermal brine, such as that produced from the lower geothermal reserve of the Salton Sea geothermal field, is diluted with non-geothermal water of much lower salinity in a mixing zone proximate the high temperature end of a geothermal power plant, and preferably down in the production well just above the production zone, so as to reduce the chloride salt content of the production brine to a level that is at or below the saturated level at reinjection temperatures, thereby preventing any material chloride salt scaling at any location in the plant through reinjection. The permanent cemented-in production casing in the well is protected against the corrosive effects of the hot production brine by means of a removable production liner that is generally coextensive with the casing.

Abstract: A system for reducing silica scaling in a geothermal power plant energized by high temperature, high silica content geothermal brine from a source such as the Salton Sea geothermal field or the Brawley geothermal field. Particulate material capable of seeding silica precipitation thereon is injected into one or more zones in heat extraction equipment such as steam separators where substantial temperature drops occur, so as to seed the precipitation of dissolved silica from the brine in suspended, particulate form rather than as scaling in the heat extraction equipment. The silica precipitation seeding may be accomplished in flash crystallizer type steam separators, and the particulate seed material may be silica particles recovered from a reactor clarifier downstream of the heat extraction equipment.

Abstract: A system for extending the operational life of the reinjection system of a geothermal power plant energized by high temperature, high silica content geothermal brine from a source such as the Salton Sea geothermal field or the Brawley geothermal field. The stream of geothermal brine which flows through the plant is passed slowly through a zone of particulate material having a large cumulative surface area in contact with the brine to seed the precipitation of dissolved silica from the brine onto the particles so as to reduce the amount of dissolved silica available for precipitation in the reinjection system. The zone of particulate material may be established as a floating silica sludge blanket in a reactor clarifier which also has a reaction zone in which silica precipitation is initiated.