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.