| 摘要 |
1507034 Crystallisation process DEJ INTERNATIONAL RESEARCH CO BV 26 Nov 1975 [6 Dec 1974] 52900/74 Heading BIG A process for separating crystallisable material out of a multi - component liquid system comprises the following steps performed in sequence latchwise: (a) confining a batch of liquid in a heat exchanger, (b) applying cooling to the heat exchanger to crystallise at least part of the crystallisable material and create a substantially coherent matrix of crystals, (c) removing the material formed in step (b) from the heat exchanger, (d) breaking up the material from step (c) into a predetermined size and (e) separating crystallised material from the remainder of the multi - component system. Suitable aparatus, as shown in Fig. 1, for the freeze concentration of e.g. aqueous systems such as coffee extract and fruit juices, comprises a storage vessel (1), a number of shell and tube heat exchangers (3-12) mounted in parallel and connected to a central feed line, below the heat exchangers are an equal number of grinding means for breaking up the columns of ice and concentrate and simultaneously mixing the broken ice with recirculated concentrate and a washing column (13) for separating ice and concentrate. The process is carried out so that at the end of each freeze cycle the pump (2) pumps feed solution into the heat exchanger and so forces the columns of ice crystals and concentrate which have formed in the heat exchanger out of the exchanger, the columns of ice having first been released from the tube walls by briefly applying heat. A new freezing cycle starts when only a small frozen plug (28) remains in each tube (27). The frozen columns are broken up upon leaving the tubes by the knives (30) driven by a motor (33). The mixture of ice and concentrates enters the mixing vessel (32) at regular intervals and is transformed into a slurry for processing by the separating apparatus i.e. a washing column (13). |
