Abstract
Krystal-Oslo type crystallizer on a pilot plant scale equipped with the evaporating heater was used to make ammonium sulfate crystals.
The operational characteristics were found from the performance data.
1. When the total crystal-bed was recycled in the state of suspension, violent formation of nuclei took place after heating, and the crystals from the bottom of suspension container were of poor growth and small diameter.
2. So long as the upward flow-velocity was controlled properly, the crystallization together with its classification was possible and approximately uniform crystals of larger diameter were easily obtained.
3. When the product particles are required to have a given length of diameter, the upward flow velocity, or the circulating flow rate cannot be varied arbitrarily. Increasing capacity is attainable by increasing the degree of supersaturation, but the preferable form of crystals can not be obtained beyond certain limits.
This pilot plant was operated most satisfactorily at the capacity of 0.4 [t/D].
4. Krystal-Oslo type crystallizer should be operated in the severely controlled range of V0, W and S.
