Patent ID: 8469091

Claim:
A method for production of purified distillate from produced water used in heavy oil production, comprising: (a) providing produced water stream extracted from a heavy oil production well; (b) deoiling said produced water stream to provide a deoiled water stream; (c) increasing the pH of said deoiled water stream to provide a softened water stream by precipitating calcium and magnesium from the deoiled water stream; (d) preheating said softened water stream in a heat exchanger; (e) deaerating said softened water stream; (f) preconcentrating said softened water stream in a first evaporation stage in an evaporator vessel including a recirculating brine by generating a water vapor stream and a concentrated brine stream; (g) demisting said water vapor stream in a mist eliminator external to the evaporator vessel to reduce solids content prior to condensation thereby creating the high purity distillate stream, wherein the demisting step comprises the stages of treating a brine-containing water vapor in at least one coarse removal chevron, treating said brine-containing water vapor with at least one mesh agglomerator pad, and treating said brine-containing water vapor in at least one polishing chevron; (h) sending the high purity distillate to a high pressure boiler or steam generator for the production of steam and subsequent injection to a reservoir via an injection well.