Abstract: NORMs are inhibited or prevented from precipitating with scale produced by a hot aqueous solution by adding multiple portions of a crystal structure modifier to the aqueous solution as it cools before and during removal of silicon containing components by precipitation. Preferred crystal structure modifiers include polyacrylate crystal structure modifiers and phosphonomethylated amines.

Abstract: Radioactivity and fluoride ion are inhibited or prevented from precipitating in scale formed from a geothermal brine by adding a scale inhibitor to the cooling brine solution. Preferred scale inhibitors include polyacrylate dispersants and phosphonomethylated amines.

Abstract: Radioactivity and fluoride ion are inhibited or prevented from precipitating in scale formed from a geothermal brine by adding a dispersant to the cooling brine solution. Preferred dispersants include polyacrylates and polyphosphonic acids.

Abstract: Geothermal brine is passed through a zone containing a packing metal so as to reduce its tendency to deposit iron/silica scale, reduce corrosivity of the brine, and/or remove and recover metals from the brine. The method polishes the geothermal brine by contacting the brine with a packing metal higher in the electromotive series than silver for a time sufficient for a precious metals to precipitate onto the packing at brine temperature and pH conditions which inhibit iron-rich silica scale. Most preferably, the contacting is accomplished near an injection well at the end of a heat extraction process and the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to also act as a filter for suspended particles. Alternatively, contacting is also accomplished near the production well. Dissolving the packing in a suitable acid leaves a precious metal-rich residue behind for subsequent recovery.

Abstract: A process is provided for controlling the emission of nitrogen dioxide from, and the growth of living organisms in, steam condensate cooling towers and catch basins used in conjunction with a condensate of steam derived from an ammonia containing geothermal brine. The process comprises contacting the condensate, in a substantially continuous manner, with a less-than-stoichiometric amount of an oxidizing agent, which results in the oxidation of nitrite in the condensate to a nitrate. The process optionally provides for periodically introducing a biocide into the condensate in an amount which controls organism growth in the cooling tower and catch basin. To prevent system corrosion, the process may include treating the condensate with a non-organic, phosphate-based corrosion inhibitor and scale dispersant.

Abstract: A process for abating the emission of hydrogen sulfide and nitrogen oxide from a condensate of steam, derived from a sulfide- and nitrite-containing geothermal brine, comprising introducing an oxidizing agent into the condensate in an amount less than that which would be required to directly oxidize all the sulfide and nitrite to sulfate and nitrate. The process optionally provides for periodically introducing a biocide into the condensate to control the growth of organism therein.

Abstract: A method is disclosed for polishing geothermal brines containing iron-rich silica scale and silica particles suspended therein while removing and recovering copper, silver and other precious metals dissolved therein. The method comprises passing brine having a pH just below about 5.0 through a conduit packed with a metal higher in the electromotive series than silver for a time sufficient for a substantial portion of the copper and silver therein to precipitate onto the packing. Preferably, the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to act as a filter for said suspended particles. Dissolving the packing in a suitable acid will leave a precious metal-rich residue behind for subsequent recovery. When the brine is treated in accordance with this method, the useful life of injection wells used to return cooled brine back to the geothermal field is extended by at least about 3 time as compared to that observed with untreated brine.

Abstract: Geothermal brine is passed through a zone containing a packing metal so as to reduce its tendency to deposit iron/silica scale, reduce corrosivity of the brine, and/or remove and recover metals from the brine. The method polished the geothermal brine by contacting the brine with a packing metal higher in the electromotive series than silver for a time sufficient for a precious metals to precipitate onto the packing at brine temperature and pH conditions which inhibit iron-rich silica scale. Most preferably, the contacting is accomplished near an injection well at the end of a heat extraction process and the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to also act as a filter for suspended particles. Alternatively, contacting is also accomplished near the production well. Dissolving the packing in a suitable acid leaves a precious metal-rich residue behind for subsequent recovery.

Abstract: A method of precipitating metals from a spent geothermal brine containing the same comprises admixing the geothermal brine with a condensate of steam, derived from the brine, in a volume ratio of brine to condensate of 1:2 to 1:10. The invention is particularly applicable to geothermal brine processes for the production of electric power, such as are practiced at the Salton Sea.

Abstract: A method is disclosed for polishing geothermal brines containing iron-rich silica scale and silica particles suspended therein while removing and recovering copper, silver and other precious metals dissolved therein. The method comprises passing brine having a pH just below about 5.0 through a conduit packed with a metal higher in the electromotive series than silver for a time to sufficient for substantially all of the silver and other precious metals therein to precipitate onto the packing. Preferably, the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to act as a filter for said suspended particles. Dissolving the packing in a suitable acid will leave a precious metal-rich residue behind for subsequent recovery. When the brine is treated this process, the useful life of injection wells used to return cooled brine back to the geothrmal field is extended by at least about 3 times as compared to that observed with untreated brine.

Abstract: A process is provided for controlling the emission of nitrogen dioxide from, and the growth of living organisms in, steam condensate cooling towers and catch basins used in conjunction with steam and condensate of steam derived from ammonia and geothermal brine containing dissolved iron. The process comprises contacting the condensate, in a substantially continuous manner, with a small, substantially less-than-stoichiometric amount of an oxidizing biocide, such as trichloroisocyanuric acid or 1-bromo-3-chloro-5,5-dimethyl-hydantoin, which results in the oxidation of said nitrite formed by activity of bacterial in the condensate to a non-reactive nitrate, and which slows the growth of said bacteria in the cooling tower and catch basin. The process additionally includes periodically introducing into the condensate with amounts of a second biocide, such as dodecylguanidine hydrochloride or isothiazalone, which provides most of the control or organism growth in the cooling tower and catch basin.

Abstract: Condensate of steam derived from a geothermal brine is treated to enhance its utility as wash water for a brine filter. The condensate is sprayed into a tank in the presence of air to effect substantial oxidation of oxidizable sulfur species contained therein, and the pH of the condensate is adjusted to be within about 1.0 pH units of the pH of the brine. Such treatment substantially extends the life of the filter media used in the brine filter.

Abstract: A process and apparatus is provided for reducing the concentration of fine, residual solids still remaining suspended in clarified geothermal brine overflow from a primary brine clarification stage in which hot, flashed, silica-rich geothermal brine, containing suspended siliceous material, is gravity separated, comprises flowing the brine overflow from the primary clarification stage into a closed secondary clarifier vessel having an internal reaction well. Capacity of the secondary clarifier vessel provides a brine residence time in the vessel of between about 45 and about 150 minutes, the brine residence time in the reaction well being between about 10 and about 20 minutes. Brine in the vessel is blanketed with steam flashed from the brine to exclude air from the vessel. In the reaction well, the brine is contacted with a flocculating agent, such as a cationic, anionic, or non-ionic polyacrylamide having a molecular weight of at least about 1 million, in an amount of between about 0.

Abstract: A method is provided for producing electric power from hot, pressurized geothermal brine containing dissolved toxic elements without significant precipitation of toxic solids. When sludge produced by the process is washed, non-toxic solids are produced which can be disposed of or utilized in an environmentally acceptable manner. The method includes removing geothermal brine from an underground aquifer, separating non-condensable gases therefrom, and handling the non-condensable gases separately from the processing of the non-condensable gas-free brine to prevent reactions therebetween. An air-free flashed brine handling system is established to prevent contact of air with the flashed brine, and all brine contacted with air is injected into the geothermal brine aquifer through a separate, corrosion-protected injection well. Steam derived from the brine is used to produce electric power, the steam being condensed in the process. The steam condensate is air-cooled, and is used in the steam condensation process.

Abstract: A process for treating hot, pressurized geothermal brine in a liquid-vapor phase separator comprises contacting the brine in the separator with between about 0.2 and about 1.5 parts per million of a defoaming agent so as to substantially reduce the amount of foaming in the separator caused, in part, by steam bubbling through the brine. The preferred defoaming agents are polyglycols having molecular weights between about 1000 and about 2500, those agents having molecular weights below about 1000 being too volatile and those above about 2500 being too difficult to solubilize in the brine.

Abstract: A process is provided for reducing the silica content in silica-rich geothermal brine having dissolved heavy metals, particularly from brine which is flashed from a high natural pressure to a reduced pressure to convert some of the brine into steam, the flashing causing the brine to become supersaturated in silica. The process comprises combining a base material with the brine, in the brine flashing stage, to increase the brine pH from its natural range of about 5 to 5.5 to a range of between about 6.2 and about 6.6, with a pH of about 6.4 being preferred. The added base, which is preferably selected from ammonia, sodium or calcium hydroxide and sodium sulfide or polysulfide, reacts with heavy metals, notably iron, copper and lead in the brine to form a finely divided, insoluble compound or compounds which function as seed crystals onto which supersaturated amounts of silica are precipitated from the brine. The base may be added to the brine in an amount of between about 200 and about 400 ppm by weight.

Abstract: A method is provided for producing power from geothermal brine comprising dissolved toxic elements without significant precipitation of toxic solids. When sludge produced by the process is washed, non-toxic solids are produced which can be disposed or utilized in an environmentally acceptable manner. The method includes removing geothermal brine, separating non-condensable gases therefrom, and handling the non-condensable gases separate from the processing of the non-condensable gas-free brine to prevent reaction therebetween. An air-free flashed brine handling system is established to prevent contact of air with the flashed brine, and all brine contacted with air including condensate from steam turbines producing electrical power is injected into the aquifer from which the geothermal brine was extracted through the use of separate injection wells.

Abstract: A process for reducing the concentration of fine, residual solids still remaining suspended in clarified geothermal brine overflow from a primary brine clarification stage in which hot, flashed, silica-rich geothermal brine, containing suspended silicious material, is gravity separated, comprises flowing the brine overflow from the primary clarification stage into a closed secondary clarifier vessel having an internal reaction well. Capacity of the secondary clarifier vessel provides a brine residence time in the vessel of between about 45 and about 150 minutes, the brine residence time in the reaction well being between about 10 and about 20 minutes. Brine in the vessel is blanketed with steam flashed from the brine to exclude air from the vessel. In the reaction well, the brine is contacted with a flocculating agent, preferably a cationic polyacrylamide having a molecular weight of at least about 1 million, in an amount of between about 0.25 and about 2 parts per million.

Abstract: A method is provided for combining a high pH steam condensate with a flow of a acidic geothermal brine from which the steam is extracted so as to inhibit the formation of suspended particulate matter, such as heavy metal sulfides, calcium carbonate and iron hydroxide, by the chemical reacting of such impurities as hydrogen sulfide and ammonia in the condensate with such impurities as heavy metals, iron and calcium in the brine. The method includes acidifying the steam condensate, preferably by hydrochloric acid, to reduce the pH to between about 7 and about 4.5 and then combining the acidified condensate with the brine. In a silica crystallizer stage in which flashed brine is contacted with a silica seed material to cause silica removal from the brine, the treated condensate is combined with the brine in a low pressure crystallizer upstream of brine clarification and reinjection stages.

Abstract: A nozzle of especial usefulness for injecting corrosive acids into geothermal brines and the like comprises a substantially straight, tubular injector body and a plurality of pairs of injection tubes connected such that the axial bores of the injection tubes are in fluid communication with the axial bore of the tubular injector body. The injection tubes of each pair extend in radial directions from, and in the same plane normal to, the axis of the tubular injector body. Moreover, all injection tubes are in one of two planes coincident to the axis of the tubular body and all pass through a plane parallel to the axis of the injector body.