| 摘要 |
The present invention is related to a separation process by which a substance can be separated in a more or less purified state from a solution containing it. In the process, the solution is partially solidified by an indirect contact cooling operation and the deposited solid is then melted in situ to yield the purified substance. High quality deposit is obtained by maintaining an appropriate flow of the solution over the surface of the deposited solid during the solidification operation and by growing the deposit at a low growth rate. Heat reuse in these operations is accomplished by the help of an auxiliary working medium which undergoes a cyclic change. The medium undergoes an endothermic transformation, such as melting, vaporization, etc., to absorb the heat liberated during the partial solidification operation and undergoes the corresponding reverse operation, which is exothermic, to supply the heat required in melting the deposited solid. Since the transformation temperatures of both the main system and the auxiliary system during the operations described above are functions of the respective applied pressures, the temperature differentials required in these heat exchange operations between the main and the auxiliary systems can be obtained by selecting a suitable working medium and by maintaining the pressure applied to these systems during the operations or appropriate values. Work is supplied to the process through the necessary pressurization operations.
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