Investigation of a novel scraped surface crystallizer with included ice-pressing section as new purification technology

Abstract Freeze desalination as a sustainable concept to produce potable water can be a useful and an additional method to overcome the water crisis, especially with ongoing global warming in focus. Therefore, a scraped surface crystallizer in combination with a post-treatment pressing cone has been built on a laboratory scale to investigate any dependencies of ice purity and throughput on operational conditions. Furthermore, a new designed screw conveyor and an additionally installed force sensor led to a better understanding of mass flow, mass fraction and ice purity. Changing the mean coolant temperature and rotational speed of the screw showed their influences on the ability to separate brine from ice and thus on the overall efficiency of the test plant. The influence of one parameter can be compensated by adjusting another, which leaves more flexibility for the operator of such a plant. Additionally, several Nusselt correlations were checked for suitability as helpful tools to design an upscale.