Forced circulation crystallizers are of the (Mixed Suspension Mixed Product Removal) MSMPR type and operate either on controlled or "natural" slurry density depending upon process requirements and/or unit material balance.
These systems can be either single or multiple effects and the vapor recompression concept (either thermal or mechanical) is often applied. Usually, they operate from low vacuum to atmosphere pressure.
As a rule, these units are used for high evaporation rates and when crystal size is not of the utmost importance or if crystal grows at a fair rate.
Almost any material of construction can be considered for the fabrication of these crystallizers.
It is worth bearing in mind that the heating element is omitted for vacuum cooling crystallizers.
Typical products are:
- NaCl (food or technical grade)
- Na2, SO4, K2 SO4
- Citric acid