Abstract: The present invention relates to a process for removing dissolved silica from a high pH brine produced by an evaporator employed in treating a waste stream. The high pH brine is directed to a crystallizer reactor and an acid or CO2 is mixed therewith to reduce the pH of the brine, causing the silica in the brine to precipitate. The brine is then directed to a first solids-liquid separator which produces a slurry containing the precipitated silica. The slurry is split into first and second streams with one stream recycled to the crystallizer reactor while the other slurry stream is directed to a second solids-liquid separator which produces a wet cake containing the silica solids.

Abstract: A process for treating wastewater or waste brines that include sodium and chloride ions. The waste brine is concentrated and thereafter directed to a Mirabilite crystallizer that produces hydrated sulfate salt crystals and a first solution. The hydrated crystals are melted to form an aqueous sulfate solution that is directed to a sodium sulfate crystallizer which produces sodium sulfate salt crystals. The first solution produced by the Mirabilite crystallizer is directed to a nanofiltration device which produces a permeate stream and a reject stream containing sulfate removed by the nanofiltration device. The permeate stream is directed to a sodium chloride crystallizer that produces sodium chloride salt crystals. The reject stream is recycled to the Mirabilite crystallizer.

Abstract: A method of concentrating and/or producing lithium hydroxide in an evaporator entails feeding a stream comprising lithium, hydroxide and carbonate to the evaporator. In the evaporator, the feed is concentrated to form lithium hydroxide and lithium carbonate crystals. Further, the method entails reducing the tendency of lithium carbonate to scale the evaporator by increasing the concentration of lithium carbonate crystals in the evaporator by: (1) clarifying at least a portion of the concentrate in the evaporator to form a clarified solution; and (2) discharging the clarified solution as a clarified solution stream from the evaporator.

Abstract: The present invention relates to a process that uses one or more evaporators to treat produced water containing silica. To address silica scaling, a crystallizing reagent is mixed with the produced water upstream of the evaporator. The crystallizing reagent is designed to precipitate a silica adsorbing compound such as magnesium hydroxide. The feedwater with the adsorbed silica is directed to an evaporator that produces a distillate and a concentrate containing the adsorbed silica. At least a portion of the concentrate having the silica adsorbing compound is directed to a separator that separates the silica adsorbing compound from the concentrate and recycles it back to where it is mixed with the produced water.

Abstract: A method of producing potassium sulfate by employing sodium sulfate and potassium chloride sources is disclosed. The method includes a crystallization process that yields a mother liquor containing sulfate, sodium and chloride. The mother liquor is directed to an anion segregation unit that produces a reject or retentate rich in sulfate which is recycled and employed in the production of the potassium sulfate. Further, the anion segregation unit produces a permeate that is depleted in sulfate but includes sodium and chloride and is directed to a sodium chloride crystallizer for producing sodium chloride.

Abstract: A process is provided for producing potassium sulfate from potassium chloride and sulfuric acid. The process entails mixing potassium chloride with the water to form a potassium chloride slurry which is mixed with recycled sulfuric acid to form a K+, Ct?, SO42? acid mixture. This mixture is subjected to a crystallization process that produces potassium sulfate crystals and a hydrochloric acid-water vapor. The hydrochloric acid is separated from the hydrochloric acid-water vapor to form a hydrochloric acid solution.

Abstract: A method of producing potassium sulfate by employing sodium sulfate and potassium chloride sources is disclosed. The method includes a crystallization process that yields a mother liquor containing sulfate, sodium and chloride. The mother liquor is directed to an anion segregation unit that produces a reject or retentate rich in sulfate which is recycled and employed in the production of the potassium sulfate. Further, the anion segregation unit produces a permeate that is depleted in sulfate but includes sodium and chloride and is directed to a sodium chloride crystallizer for producing sodium chloride.

Abstract: A system and process is disclosed for treating foul condensate such as foul condensate produced in a Kraft pulp mill. Foul condensate is directed through a steam stripper to produce a clean condensate that is partially evaporated by a volatile rich vapor stream produced by the steam stripper in the course of treating the foul condensate. Vapor produced by the evaporation of the clean condensate is directed to one or more electrically driven mechanical vapor re-compressors that produce the steam that is used in the steam stripper.

Abstract: A process is provided for producing potassium sulfate from potassium chloride and sulfuric acid. The process entails mixing potassium chloride with the water to form a potassium chloride slurry which is mixed with recycled sulfuric acid to form a K?, Ct?, SO42? acid mixture. This mixture is subjected to a crystallization process that produces potassium sulfate crystals and a hydrochloric acid-water vapor. The hydrochloric acid is separated from the hydrochloric acid-water vapor to form a hydrochloric acid solution.

Abstract: A process for treating wastewater or waste brines that include sodium and chloride ions. The waste brine is concentrated and thereafter directed to a Mirabilite crystallizer that produces hydrated sulfate salt crystals and a first solution. The hydrated crystals are melted to form an aqueous sulfate solution that is directed to a sodium sulfate crystallizer which produces sodium sulfate salt crystals. The first solution produced by the Mirabilite crystallizer is directed to a nanofiltration device which produces a permeate stream and a reject stream containing sulfate removed by the nanofiltration device. The permeate stream is directed to a sodium chloride crystallizer that produces sodium chloride salt crystals. The reject stream is recycled to the Mirabilite crystallizer.

Abstract: The present invention relates to a process that uses one or more evaporators to treat produced water containing silica. To address silica scaling, a crystallizing reagent is mixed with the produced water upstream of the evaporator. The crystallizing reagent is designed to precipitate a silica adsorbing compound such as magnesium hydroxide. The feedwater with the adsorbed silica is directed to an evaporator that produces a distillate and a concentrate containing the adsorbed silica. At least a portion of the concentrate having the silica adsorbing compound is directed to a separator that separates the silica adsorbing compound from the concentrate and recycles it back to where it is mixed with the produced water.

Abstract: An evaporation system employs a thermocompressor to recover heat associated with a distillate produced by an evaporator and to use the recovered heat to preheat evaporator feedwater. In one example, the thermocompressor produces a thermocompressor discharge that is directed into the deaerator, contacting and preheating the evaporator feedwater passing therethrough. In another example, the thermocompressor discharge is directed through a barometric condenser which contacts evaporator feedwater therein and condenses and in the process preheats the evaporator feedwater.

Abstract: A process for treating wastewater or waste brines that include sodium and chloride ions. The waste brine is concentrated and thereafter directed to a Mirabilite crystallizer that produces hydrated sulfate salt crystals and a first solution. The hydrated crystals are melted to form an aqueous sulfate solution that is directed to a sodium sulfate crystallizer which produces sodium sulfate salt crystals. The first solution produced by the Mirabilite crystallizer is directed to a nanofiltration device which produces a permeate stream and a reject stream containing sulfate removed by the nanofiltration device. The permeate stream is directed to a sodium chloride crystallizer that produces sodium chloride salt crystals. The reject stream is recycled to the Mirabilite crystallizer.

Abstract: Wood pulping process including pulping wood to produce a pulping effluent or liquor. Pre-concentrating the liquor in a pre-concentration unit produces concentrated liquor, a contaminated condensate and a non-contaminated condensate. Directing the concentrated liquor to a multi-effect train of forced circulation solids concentrators that further concentrating the concentrated liquor to form a highly concentrated liquor. Directing the contaminated condensate produced by the pre-concentration unit to a steam stripper and stripping gases therefrom and in the process producing a contaminated vapor stream. Utilizing the contaminated vapor stream and its thermal energy to power the forced circulation solids concentrators of the multi-effect train.

Abstract: A method for treating produced water or a feedwater stream with an evaporator. The feedwater stream or produced water is directed to and through a deaerator located upstream of the evaporator. Steam produced by the evaporator is utilized to strip dissolved gases from the produced water or feedwater stream passing through the deaerator. To efficiently strip dissolved gases, the vapor pressure in the deaerator is maintained at below atmospheric pressure and the produced water or feedwater stream is heated to a temperature greater than the saturated vapor temperature in the deaerator.

Abstract: An evaporation system employs a thermocompressor to recover heat associated with a distillate produced by an evaporator and to use the recovered heat to preheat evaporator feedwater. In one example, the thermocompressor produces a thermocompressor discharge that is directed into the deaerator, contacting and preheating the evaporator feedwater passing therethrough. In another example, the thermocompressor discharge is directed through a barometric condenser which contacts evaporator feedwater therein and condenses and in the process preheats the evaporator feedwater.

Abstract: A method of concentrating and/or producing lithium hydroxide in an evaporator entails feeding a stream comprising lithium, hydroxide and carbonate to the evaporator. In the evaporator, the feed is concentrated to form lithium hydroxide and lithium carbonate crystals. Further, the method entails reducing the tendency of lithium carbonate to scale the evaporator by increasing the concentration of lithium carbonate crystals in the evaporator by: (1) clarifying at least a portion of the concentrate in the evaporator to form a clarified solution; and (2) discharging the clarified solution as a clarified solution stream from the evaporator.

Abstract: An oil recovery process includes recovering an oil-water mixture from an oil-bearing formation and separating the produced water from the oil-water mixture. The produced water includes dissolved gases and the method includes heating and pressurizing the produced water. After the produced water is heated and pressurized, it is flash vaporized through a lesser pressure which produces a vapor and residual produced water. The flash vaporization of the produced water evaporates dissolved gases and the dissolved gases are vented away with the vapor.

Abstract: A system and process is disclosed for treating foul condensate such as foul condensate produced in a Kraft pulp mill. Foul condensate is directed through a steam stripper to produce a clean condensate that is partially evaporated by a volatile rich vapor stream produced by the steam stripper in the course of treating the foul condensate. Vapor produced by the evaporation of the clean condensate is directed to one or more electrically driven mechanical vapor re-compressors that produce the steam that is used in the steam stripper.

Abstract: The present invention relates to a process for treating evaporator concentrate. The process includes generating or producing a vent stream that includes carbon dioxide and mixing the carbon dioxide with the evaporator blowdown to reduce the pH of the evaporator blowdown. In cases where the evaporator blowdown includes a significant concentration of silica, lowering the pH will precipitate silica from the evaporator blowdown.