Radial counterflow inductive desalination
Simultaneous source-sink flow, or radial counterflow, is driven by a centrifugal pump disposed within a casing. Radially outward source flow of brine goes into a shrouding tank and concentrates while a radially inward sink flow of fresh water flows back over the pump to axial extraction. An axial pump drives sink flow and axial extraction. Convergent sink flow passes under an inductor to an axial exhaust port. Induced viscosity and inductive repulsion hinder the passage of brine in sink flow, so only fresh water can reach the axial exhaust port. Crystallization of scale-forming salts is aided by Joule heating from the inductor. Solvent and gases are continuously axially extracted in sink flow, favoring crystallization. Sodium chloride is cooled and crystallized in the shrouding tank. Brine comprising other salts flows out of the tank to treatment by suitable means. Thus brine is separated into fresh water, crystallized salt, and concentrated brine.
1. An apparatus for separating a brine, comprising:
a casing having a centerline, the casing comprising an axial feed port and an axial exhaust port, both ports being coaxial with the centerline;
a rotatable centrifugal pump disposed within the casing and connected to a driver, the centrifugal pump having an axis of rotation at said centerline and the centrifugal pump configured to draw brine into the casing through the axial feed port;
a tank communicating with the interior of the casing and configured such that brine from the axial feed port, when advected radially outward from the centerline by the centrifugal pump, collects and concentrates in the tank;
a rotatable baffle disposed between the axial feed port and the axial exhaust port and spaced apart from the casing so as to define a high-shear radially inward sink flow passage for water from the brine to be extracted from the casing through the axial exhaust port; and
at least one radio frequency bifilar pancake coil adapted to repel brine from flow in the sink flow passage into brine advected radially outward by the centrifugal pump when the apparatus is operative, the coil disposed above the sink flow passage.
2. The apparatus of claim 1 , further comprising an axial pump communicating with the sink flow passage through the axial exhaust port, the axial pump configured such that flow through the sink flow passage goes through the axial exhaust port and through the axial pump.
3. The apparatus of claim 1 , wherein the tank comprises means for evacuating solids and concentrated brine contained therein.
4. The apparatus of claim 1 , wherein the baffle is connected to the centrifugal pump and rotates therewith.
5. The apparatus of claim 1 , wherein the centrifugal pump comprises at least one runner having grooves transverse to the flow over the runner.
6. The apparatus of claim 1 , further comprising means for collecting metals, said metal collecting means disposed below the axial feed port.
7. The apparatus of claim 1 wherein the radially inward sink flow passage extends substantially between the tank and the axis.
8. The apparatus of claim 1 wherein the tank is substantially annular in shape and wherein the tank communicates with the interior of the casing at the radially inward side of the tank.
9. The apparatus of claim 8 wherein the tank communicates with the interior of the casing substantially entirely along the radially inward side of the tank.
10. The apparatus of claim 1 wherein a portion of the casing comprises substantially parallel plates that define a substantially planar space, the pump having blades that are contained within the space.
11. The apparatus of claim 1 wherein the casing adjacent the sink flow passage is made from dielectric material.
12. The apparatus of claim 1 , comprising a passage for sink flow of solids below the baffle and over a bottom wall of the casing into the axial feed port.
13. The apparatus of claim 1 , further comprising a chilling jacket for cooling brine in the tank.
14. The apparatus of claim 3 , wherein said means for evacuating solids and concentrated brine comprise a concentrated brine port and a crystallized solids port.
15. The apparatus of claim 1 , wherein said sink flow passage above the baffle has a radius at least twice its height.