Patent ID: 7686079

Claim:
A method for recovering oil and removing silica from produced water, the method comprising: a. recovering an oil-water mixture from an oil well; b. separating oil from the oil-water mixture to produce an oil product and produced water having silica; c. directing the produced water to an evaporator and producing a distillate and an evaporator concentrate having silica; d. directing the distillate to a steam generator, producing steam from the distillate, and directing the produced steam into the oil well; e. directing the evaporator concentrate to a first crystallizer; f. mixing an alkaline earth reagent with the evaporator concentrate and precipitating silica from the evaporator concentrate to form one or more alkaline earth silicate complexes, wherein the one or more alkaline earth silicate complexes form crystals in the evaporator concentrate; g. directing the evaporator concentrate having the one or more alkaline earth silicate complexes to a separator; h. separating the one or more alkaline earth silicate complexes from the evaporator concentrate and producing an aqueous solution and a slurry containing the one or more alkaline earth silicate complexes; i. directing at least a first portion of the slurry to a filter, filtering at least the first portion of the slurry to separate solids from the first portion of the slurry, and producing a filtrate; and j. disposing of the aqueous solution.