This crystallizer style is used for medium to large capacity projects employing large circulation rates, large crystallizer bodies, and usually employs axial flow circulation pumps.
Boiling on the tubes of the vertical calandria (heated section) is suppressed by the height of liquid above the top tubesheet. Superheated liquid releases its vapor within the crystallizer body submerged zone creating a supersaturated mass of liquid at the vapor liquid interface promoting crystal growth. Crystal size and distribution are controlled by magma density (crystal population), residence time and removal of fines in a settler and centrifuge sub-system. Selective crystal size distribution is not controlled by elutriation legs as in the case of the more specialized crystallizer body alternate designs. This design has been used for anhydrous sodium sulfate production and many other inorganic mined and chemically produced salts.
Evaporative crystallizers tend to yield larger average crystal size and narrows the crystal size distribution curve.