US4228089A
Expired / Lapsed
US
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Method and apparatus for fractional crystallization separation
Assignee: Sulzer AG
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Filing: 1978-05-24
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Granted: 1980-10-14
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Expires: 1998-05-24
Abstract
Abstract A method for separating components of a substance, for example, a fatty acid ester such as palm oil, by dissolving the substance in a solvent. The resultant solution is circulated and cooled in a circuit with crystals being formed in the solution as the temperature is lowered. The crystals are continuously separated from the circulating solution during the crystal separation phase of the process. The crystals are then preferably washed and recovered. Preferably there is a second crystallization phase in the process. The invention includes the apparatus used to carry out the process and, particularly, novel fractionating columns and filter surfaces within said columns used in the preferred embodiments of the process.
Inventors
- 👤 Rudolf Bischof
- 👤 Heinz Rhyner
- 👤 Kurt Saxer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:49
CPC Classifications
C; C11; C11B; C11B7/00; C11B7/0008; B; B01; B01D; B01D35/00; B01D35/18; B01D35/22; B01D9/00; B01D9/0004; B01D9/004; B01D9/0059; C07; C07C; C07C67/00; C07C67/48; C07C67/52
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
160 words
A method for fractionation of a mixture of fatty acid esters materials dissolved in a solvent, said method comprising circulating and cooling the solution in a circuit, said circuit comprising a circulating pump, a cooler, a heater, a storage tank and a fractionation column, said fractionation column further comprising at least one filter surface, stage (1) lowering the temperature gradually, causing formation of crystals suspended within said solution, said crystals forming while totally suspended within the solution, and continuously separating the crystals from the circulating solution by passing the crystal-containing solution in contact with said at least one filter surface whereby crystals are collected on said at least one crystal surface and then recovering the material forming said crystals, and stage (2) further lowering the temperature of said solution and repeating the procedure of stage (1) whereby crystals having a lower crystallization temperature than those formed in stage (1) are formed and collected on said at least one filter surface.
Claim 2
Independent Claim
160 words
A method for fractionation of a mixture of fatty acid esters materials dissolved in a solvent, said method comprising circulating and cooling the solution in a circuit, said circuit comprising a circulating pump, a cooler, a heater, a storage tank and a fractionation column, said fractionation column further comprising at least one filter surface, stage (1) lowering the temperature gradually, causing formation of crystals suspended within said solution, said crystals forming while totally suspended within the solution, and continuously separating the crystals from the circulating solution by passing the crystal-containing solution in contact with said at least one filter surface whereby crystals are collected on said at least one crystal surface and then recovering the material forming said crystals, and stage (2) further lowering the temperature of said solution and repeating the procedure of stage (1) whereby crystals having a lower crystallization temperature than those formed in stage (1) are formed and collected on said at least one filter surface.
Claim 3
Dependent Claim
18 words
The method of claim 1, wherein the separation of the crystals is carried out in a fractionating column.
Claim 4
Dependent Claim
14 words
The method of claim 2, wherein the separated crystals are washed with cold solvent.
Claim 5
Dependent Claim
14 words
The method of claim 2, wherein the separated crystals are removed with hot solvent.
Claim 6
Dependent Claim
14 words
The method of claim 3, wherein the separated crystals are removed with hot solvent.
Claim 7
Dependent Claim
22 words
The method of claim 3, wherein after fractionation, the solvent is recovered from the fractions by distillation and reintroduced into the circuit.
Claim 8
Dependent Claim
27 words
The method of claim 3, wherein the solvent used for washing is stored in a tank and is fed to the circuit on a subsequent crystallization cycle.
Claim 9
Dependent Claim
17 words
The method of claim 1, wherein said mixture of materials is a mixture of fatty acid glycerides.
Claim 10
Dependent Claim
13 words
The method of claim 1, wherein said mixture of materials is palm oil.
Claim 11
Dependent Claim
12 words
The method of claim 1, wherein said solvent is a liquid alkane.
Claim 12
Dependent Claim
10 words
The method of claim 10, wherein said solvent is hexane.
Claim 13
Dependent Claim
40 words
The method of claim 9 or 11, wherein the run takes place for a short time at 20° C. and then the temperature is slowly and linearly lowered to minus 15° C. to form the crystals of the first fraction.
Claim 14
Dependent Claim
17 words
The method of claim 12, wherein the crystals are washed with solvent at about minus 15° C.
Claim 15
Dependent Claim
27 words
The method of claim 13, wherein the temperature is lowered from about minus 15° C. to about minus 24° C. to form crystals of a second fraction.
Claim 16
Dependent Claim
19 words
The method of claim 14, wherein the crystals of said second fraction are washed at about minus 24° C.
Claim 17
Independent Claim
93 words
An apparatus for crystal fractionation of a mixture of materials dissolved in a solvent, said apparatus comprising in a circuit a circulation pump, a cooler, a heater, a storage tank and a fractionating column for separating the crystals from the circulated solution, said fractionating column comprising a plurality of filter surfaces located one above the other, said filter surfaces comprising spaced holes permitting a fluid flowing through or over the filter material to drop to the next lower filter surface, said holes of adjacent filter surfaces being off-set with respect to each other.
Claim 18
Independent Claim
93 words
An apparatus for crystal fractionation of a mixture of materials dissolved in a solvent, said apparatus comprising in a circuit a circulation pump, a cooler, a heater, a storage tank and a fractionating column for separating the crystals from the circulated solution, said fractionating column comprising a plurality of filter surfaces located one above the other, said filter surfaces comprising spaced holes permitting a fluid flowing through or over the filter material to drop to the next lower filter surface, said holes of adjacent filter surfaces being off-set with respect to each other.
Claim 19
Dependent Claim
18 words
An apparatus as claimed in claim 16, wherein the cooler and the heater are a combined cooling/heating unit.
Claim 20
Dependent Claim
12 words
The apparatus of claim 16, wherein the filter surfaces are horizontally located.
Claim 21
Dependent Claim
19 words
The apparatus of claim 18, wherein the filter surfaces are mounted on spacer means being spaced from each other.
Claim 22
Dependent Claim
30 words
The apparatus of claim 16, wherein said fractionating column contains a distributor plate above the filter surfaces, and wherein said spacer means are tubes extending somewhat above the distributor plate.
Claim 23
Dependent Claim
32 words
The apparatus of claim 16, wherein each filter surface comprises a layer of a filter material and a support for said layer, said support having a flat sieve or perforated sheet surface.
Claim 24
Dependent Claim
16 words
The apparatus of claim 21, having a wire mesh on the upper surface of said layer.
Claim 25
Dependent Claim
41 words
The apparatus of claim 21, wherein said perforated sheet surface contains a plurality of closely spaced small holes, distributed substantially over its whole surface, and on said sheet, another layer having a plurality of holes being larger than said small holes.
Claim 26
Dependent Claim
15 words
The apparatus of claim 21, wherein said layer comprises a felt consisting of synthetic fibres.
Claim 27
Dependent Claim
19 words
The apparatus of claim 24, wherein the pores of the felt have a diameter of 10 to 100 microns.
Claim 28
Dependent Claim
11 words
The apparatus of claim 24, wherein the synthetic fibres are polypropylene.
Claim 29
Dependent Claim
12 words
The apparatus of claim 24, wherein the synthetic fibres are of polyester.
Claim 30
Dependent Claim
18 words
The apparatus of claim 16, wherein the fractionating column comprises slightly inclined filter surfaces connected for crosscurrent flow.
Claim 31
Dependent Claim
20 words
The apparatus of claim 28, characterized in that a distributing device is provided at the top of the fractionating column.
Claim 32
Dependent Claim
23 words
The apparatus of claim 16, wherein the fractionating column comprises at least one filter in the form of a vertically arranged archimedic screw.
Claim 33
Dependent Claim
31 words
The apparatus of claim 16, wherein at least one intermediary tank is provided to store the solvent used for washing and to feed it to the circuit on a consecutive fractionating.
Claim 34
Dependent Claim
16 words
The apparatus of claim 21, wherein said spacer means are tubes extending above said distributor plate.
Claim 35
Independent Claim
126 words
A method for fractionation of a mixture of materials dissolved in a solvent, said method comprising circulating and cooling the solution in a circuit, said circuit comprising a circulating pump, a cooler, a heater, a storage tank and a fractionation column, said fractionating column further comprising a plurality of filter surfaces located one above the other, said filter surfaces comprising spaced holes permitting a fluid flowing through or over the filter material to drop to the next lower filter surface, said holes of adjacent filter surfaces being off-set with respect to each other; lowering the temperature gradually, causing formation of crystals suspended within said solution, said crystals forming while totally suspended within the solution; and continuously separating the crystals from the circulated solution fatty acid esters.
Claim 36
Independent Claim
126 words
A method for fractionation of a mixture of materials dissolved in a solvent, said method comprising circulating and cooling the solution in a circuit, said circuit comprising a circulating pump, a cooler, a heater, a storage tank and a fractionation column, said fractionating column further comprising a plurality of filter surfaces located one above the other, said filter surfaces comprising spaced holes permitting a fluid flowing through or over the filter material to drop to the next lower filter surface, said holes of adjacent filter surfaces being off-set with respect to each other; lowering the temperature gradually, causing formation of crystals suspended within said solution, said crystals forming while totally suspended within the solution; and continuously separating the crystals from the circulated solution fatty acid esters.
References Cited (Backward Citations)
US2576841A
Cited
US3621664A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |