Heat transfer in scraped eutectic crystallizers

Heat transfer phenomena in two types of eutectic crystallizers have been analyzed. This equipment is equipped with rotating scraper blades and the effect of the blade action on heat transfer phenomena in both crystallizing and non-crystallizing conditions is studied. It was found that the coolant flow in the equipment can be described by fitted Dittus-Boelter relations. In both crystallizers the transport of heat from process liquid to cooled wall surfaces at various rotational speeds of the scrapers can generally be accurately described with penetration theory. Exceptions are approximated with fitted Re-Pr-relations. Both increasing and decreasing heat transfer rates have been found in crystallizing conditions at increasing scraping rates. Differences are attributed to geometrical crystallizer characteristics and solid content.