Method and apparatus for fractional crystallization separation
AssigneeMetallwerk AG Buchs
InventorsRudolf Bischof, Heinz Rhyner, Kurt Saxer
Life of this patent
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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.
Claims33
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.
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.
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.
Dependencies are inferred from the claim text.