Crystallization process and Crystal growth is a unique combination of ‘Science and Art’ controlled by concentrations , cooling gradient and residence time under supersaturated conditions.
Continuous crystallizers is always preferable as its provides the steady state conditions at reasonably constant temperature , concentration and residence time delivering larger size crystals.
Heat removal system for crystallization is largely controlled by chemistry and behavior of the solids Heat transfer depend upon the nature of the crystals deposited on the heat exchange area .Periodic cleaning of heat transfer surface is tricky issue to be handled .When incrustation of heat transfer surface is inevitable , we have to opt for different heat removal system . The heat removal system determine the choice between continuous atmospheric crystallization and vacuum crystallization.
In both the systems the mass of crystallizer is circulated by a pump and suitable heat recovery system . The feed is introduced at appropriate place to release it’s supersaturation on the Nuclei available in the mass Technologies like Forced Circulation / Draft Tube / OSLO /IFC and Controlled Turbulence are used to achieve right level of agitation creating suspension of solids leading to ‘Crystal Growth’.
Continuous crystallization system operating under Atmospheric pressure and Vacuum system are successfully operating and developing larger crystals.