Method and apparatus for the counter-current mass exchange between two phases having different densities

• US 4,623,466 A
• Filed: 03/11/1982
• Issued: 11/18/1986
• Est. Priority Date: 03/24/1981
• Status: Expired due to Fees

• Current Assignee: Degrémont (Suez Environnement Company)
• Original Assignee: Degrémont (Suez Environnement Company)
• Inventors: Savall, Vincent
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/357,316
• Time in Patent Office: 1,713 Days
• Field of Search: 210/634, 210/673, 210/674, 210/675, 210/676, 210/264, 210/268, 210/277, 210/278, 210/189
• US Class Current: 210/634
• CPC Class Codes: B01D 11/0242 in towers, e.g. comprising contacting elements
• CPC Class Codes: B01D 11/0426 Counter-current multistage extraction towers in a vertical or sloping position
• CPC Class Codes: B01J 47/11 in rotating beds

Abstract

This invention provides a method and an apparatus for effecting counter-current mass exchange between two non-miscible phases A and B, for example a liquid phase A and a liquid or solid phase B, circulating in opposite directions from one end to an opposite end of a vertical tower comprising a plurality of superposed chambers in which the first phase A is caused to circulate continuously and the second phase B is caused to circulate discontinuously. One chamber is empty and is adapted to receive the phase B contained in the next chamber thereabove, the two chambers being isolated from any supply of phases A and B. A small fraction of the liquid phase A is diverted for directing continuously this phase to the other chambers of the tower, the thus diverted fraction being introduced into the next chamber above the empty chamber for carrying away the phase B contained in the lower empty chamber, this diverted fraction being reintroduced into the circuit.

Claims

1. A method for the counter-current mass exchange between first and second non-miscible phases have different densities, said method comprising the steps of:

(a) providing a vertical tower having opposite vertically spaced ends and defining a plurality of separate superposed chambers;

(b) continuously circulating said first phase, serially in a first direction from a first end of said tower to a second end of said tower, through all of said chambers except first and second adjacent said chambers;

(c) discontinuously circulating said second phase, serially in a second direction opposite to said first direction and from said second end of said tower to said first end of said tower, through all of said chambers except said first chamber of said adjacent chambers closest to said first end of said tower, whereby said first chamber is free of both said first phase and said second phase, said discontinuous circulation comprising;

(d) diverting a small portion of said first phase from said serial circulation thereof and introducing said small portion into said second chamber of said adjacent chambers closest to said second end of said tower, and by said small portion of said first phase carrying away said second phase in said second chamber from said second chamber and transferring it in said second direction to said first chamber, whereby said second chamber then is free of both said first phase and said second phase;

(e) reintroducing said small portion of said first phase into the supply of said first phase to thereby again be continuously circulated in said first direction;

(f) adjusting said serial continuous circulation of said first phase to be through all of said chambers except said second chamber and a third chamber adjacent said second chamber in said first direction toward said second end of said tower;

(g) periodically repeating said steps (d) through (f) to sequentially and discontinuously transfer said second phase in said second direction through said chambers;

(h) periodically discharging said second phase from the endmost said chamber at said first end of said tower; and

(i) continuously discharging said first phase from a said chamber adjacent said second end of said tower.

2. A method as claimed in claim 1, wherein said diverted small portion of said first phase comprises from 5% to 20% of the total circulation of said first phase.

3. A method as claimed in claim 1, wherein the density of said second phase is greater than the density of said first phase, said first phase is circulated continuously upwardly through said chambers of said tower, and said second phase is circulated discontinuously downwardly through said chambers of said tower.

4. A method as claimed in claim 1, wherein the density of said first phase is greater than the density of said second phase, said first phase is circulated continuously downwardly through said chambers of said tower, and said second phase is circulated discontinuously upwardly through said chambers of said tower.

5. A method as claimed in claim 1, wherein said second phase comprises an ion exchange resin.

6. A method as claimed in claim 5, wherein said ion exchange resin is discharged periodically from said endmost chamber of said tower for regeneration of said ion exchange resin.

7. A method as claimed in claim 5, wherein mass exchange takes place in fluidized beds of said ion exchange resin and said first phase in said chambers.

8. An apparatus for achieving counter-current mass exchange between first and second non-miscible phases having different densities, said apparatus comprising:

a vertical tower having opposite vertically spaced ends and defining a plurality of separate superposed chambers;

each said chamber having first inlet means and outlet means for the respective introduction and discharge of a first phase;

each said chamber having second inlet means and outlet means for the respective introduction and discharge of a second phase;

circulation means, including a single pump, for continuously circulating a predetermined quantity of said first phase in a first direction from a first end of said tower to a second end of said tower;

first valve means, associated with said first inlet means and outlet means and with said circulation means, for passing said continuous circulation of said first phase serially through said chambers in said first direction;

second valve means, associated with said circulation means and with said first inlet means and outlet means, for isolating at a given time selected first and second adjacent said chambers from said continuous circulation of said first phase;

means for discontinuously circulating said second phase, serially in a second direction opposite to said first direction and from said second end of said tower to said first end of said tower, through said chambers except for said first chamber of said selected adjacent chambers closest to said first end of said tower, said second phase circulating means comprising;

means for diverting a small portion of said first phase from said continuous circulation thereof and introducing said small portion into said second chamber of said selected adjacent chambers closest to said second end of said tower, such that said small portion of said first phase under the influence of said single pump carries away said second phase in said second chamber from said second chamber and transfers it through the respective second outlet means and inlet means in said second direction to said first chamber, whereby said second chamber then is free of both said first phase and said second phase; and

means, associated with said respective second outlet means and inlet means, for reintroducing said small portion of said first phase into the supply of said first phase to thereby again be continuously circulated in said first direction;

means for periodically discharging said second phase from the endmost said chamber at said first end of said tower; and

means for continuously discharging said first phase from a said chamber adjacent said second end of said tower.

9. An apparatus as claimed in claim 8, wherein said first inlet means and outlet means comprise perforated members having perforations of a size several times larger than the largest particle size of said second phase.

10. An apparatus as claimed in claim 8, wherein each said chamber has a flat bottom.

11. An apparatus as claimed in claim 8, wherein each said chamber has a bulged bottom.

12. An apparatus as claimed in claim 8, wherein each said chamber has a frusto-conical bottom.

13. An apparatus as claimed in claim 8, wherein each said second inlet means and outlet means comprises a respective valved conduit extending from one said chamber to the next adjacent lower said chamber.

14. An apparatus as claimed in claim 8, wherein said reintroducing means comprises, for each said chamber, a valved conduit extending from the respective chamber, a balancing conduit connected to said valved conduits of all said chambers, and a buffer tank receiving said small portion of said first phase from a discharge of said balancing conduit, said single pump withdrawing said first phase from said buffer tank.