The Dissolver unit operation models the dissolution of solids into liquid solutions. This mass transfer operation is widely used in the chemical industry in both organic as well as inorganic processes.
The dissolver transforms crystals in solution from the solid to the liquid phase. PRO/II models the most common type of dissolver which is the stirred tank dissolver. A feed heat exchanger may be included in the model if required.
A Solid-liquid equilibrium method must be defined in terms of solubility, which is calculated from either the Van't Hoff equation or user-supplied solubility data.
You must select Design or Rating calculations in the Dissolver Calculation Mode Window. In design mode, a specification is required and the volume is calculated for a given feed particle size distribution and operating conditions. In rating mode, the vessel volume is defined and the exit particle size distribution is determined.
The mass transfer coefficient may be specified in the Dissolver Dissolution Rate Window. Alternatively, you may specify that the coefficient should be calculated from diffusivity data entered in the Thermodynamic Data.
Full details of the calculation method can be found in the PRO/II Reference Manual.
The dissolver unit can have any number of feed streams. The inlet pressure is taken to be the lowest pressure of all the feed streams.
Both an overhead and bottoms product must be specified. The default allocation may be modified in the Dissolver Products Window. The bottoms contains the liquid product along with any remaining crystals. The overhead contains any vapor generated in the unit.
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