Vacuum cooling of salt solutions in crystalliser - using steam ejectors to remove and re-compress water vapour which is then condensed in surface condenser

摘要

Aqueous salt solns. are cooled by a vacuum technique using steam ejectors to extract the vapour at low pressure. The water vapour extracted is simultaneously compressed in the ejector and finally condensed in a surface condenser. The condenser is cooled by brine or can be directly cooled by refrigerant. In the latter case, the condenser serves as the evaporator for the refrigeration circuit. For use in cooling crystalliser solns. to produce crystals. Vacuum cooling is generally limited to 5 degrees C because of difficulties in condensing the water vapour drawn off. The system described overcomes this by compressing the vapour and allowing it to be condensed at a higher temp.