Flash evaporation using surface active agent and immiscible liquid

Claim 1

A multiple cycle multiple stage flash evaporation and condensation system comprising a first series of flash evaporation stages arranged to permit a continuous flow therethrough of a solution having a volatile component and to subject said solution to progressively decreasing temperatures in each stage whereby vaporization of said component takes place at lower temperatures in each stage, a second similar series of evaporation stages, means for reheating said solution after its passage through said first series of stages and fOr transferring the heated solution to said second series of evaporation stages, a common series of condenser stages maintained at successively lower temperatures for condensing the vapors produced in each of said series of evaporation stages and vapor transfer means for transferring vapors from said evaporation stages to said condenser stages for condensation thereof, said vapor transfer means from said second series of evaporation stages being arranged to bypass at least the highest temperature portion of said series of condenser stages to compensate for increased boiling point elevation of the solution passing through said second series of evaporation stages.

Claim 3

A method for separately recovering sodium chloride and calcium salts from a concentrated brine solution containing water insoluble calcium salts and admixed with a heat carrying oil and further containing a surfactant capable of reducing the interfacial tension between the concentrated solution and said oil, the steps of stratifying as substantially separate entities, the oil, the concentrated brine solution, an interphase of the calcium salts plus surfactant and lastly, precipitated sodium chloride, separating the oil and the concentrated brine solution from the interphase, adding dilute brine solution to and mixing it with the separated interphase to form a first modified solution containing said interphase and said dilute brine solution, settling said calcium salts from said first modified solution to form a further modified solution comprising brine and dissolved surfactant forming a heated mixture of said further modified solution and oil, and vaporizing water from said heated mixture to concentrate said solution and precipitate sodium chloride.

Claim 5

A method for separating a volatile solvent from a liquid solution of non-volatile solute by evaporation which comprises contacting said solution in a vaporization zone with a liquid heat transfer medium substantially insoluble in said solution and a surface active agent for reducing interfacial tension between the solution and the medium said contacting being effected under conditions of pressure and temperature effective to vaporize a portion of said volatile solvent, thereby increasing the concentration of solute therein and decreasing the solubility of surface active agent in the remaining portion of the solvent by an amount such that at least the latter part of the evaporation is effected in the presence of dispersed particles of surface active agent, and, during said latter part of the evaporation, wherein neither the heat transfer medium nor the surface active agent is readily soluble in the remaining concentrated solution, promoting heat transfer from the heat transfer medium to the solution by maintaining the solution, the heat transfer medium and the surface active agent in a state of agitation to maintain said particles of surface active agent dispersed within the mixture of solution and heat transfer medium thereby to reduce the solution-liquid heat transfer medium interfacial tension.