| 摘要 |
A wet and dry distillative freezing process is provided which comprises (a) a first step of transforming a liquid feed mixture into a first solid-liquid mixture, denoted as K-1 mixture, by either a conventional freezing operation or a wet distillative freezing operation, (b) a second step of washing the K-1 mixture with a wash liquid to thereby form a second solid-liquid mixture, denoted as Ko mixture, and an impure liquid Lo, and (c) a third step of subjecting the Ko mixture to a dry distillative freezing operation to thereby form a mass of refined solid phase, denoted as S1, and a low pressure vapor V1. Various wash liquids may be used in the crystal washing step. It is important to note that the wash liquid used does not have to be a pure liquid but may contain some volatile impurities. This is so, because the volatile impurities in the wash liquid will be taken up in the Ko mixture and will be removed in the dry distillative freezing step. Convenient wash liquids to use are (a) a mass of the feed liquid, (b) a mass of the condensate liquid, and (c) a part of the product liquid. One may also use a solution containing the crystallizing component and a selected volatile component as a wash liquid. |
