This operation simulates the coating of tablets or other discrete entities; this process takes place in the final stages of the product formulation in the pharmaceutical industry. The tablets are fed to the coater and a finite amount of bulk liquid is sprayed and added to the tablet. Air is simultaneously spayed, and the volatile components are removed.
The user specifies the amount of spraying solution that is used for coating each tablet (either in mass and volume per entity) and the amount of liquid solution needed is calculated. The user also specifies the relative / absolute flowrate. The amount of volatile components removed from the tablets is calculated based on the evaporation fraction defined by the user. The volatile components and the air exit from the vent stream, the coated tablets from the main output.
The equipment is sized based on its volume. The bulk volume of the coated tablets is calculated based on the option selected by the user. The user defines in the volumes tab whether the bulk volume is calculated based on a user-defined bulk density or on a user-defined volume per entity.
In Design Mode of calculation, the user specifies the working to vessel volume ratio (through the Volumes tab) and the program sets the working volume (Vw) equal to the bulk volume of material that is processed per cycle. The number of cycles per batch is specified through the Scheduling tab. The vessel volume (V) is calculated using the following equation:
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If the calculated volume exceeds its maximum possible value (specified through the Equipment tab), the program assumes multiple (identical) units operating in parallel with a total vessel volume equal to the calculated.
In Rating Mode, the user specifies the vessel volume and the number of units. The program calculates the working to vessel volume ratio and warns the user if its value is outside of its minimum and maximum limits.
The interface of this operation has the following tabs:
● Oper. Cond’s, see Tablet Coating: Oper. Conds Tab
● Volumes, see Discrete Operations: Volumes Tab
● Utility Data, see Tablet Coating: Utility Data Tab
● Labor, etc, see Operations Dialog: Labor etc. Tab
● Description, see Operations Dialog: Description Tab
● Batch Sheet, see Operations Dialog: Batch Sheet Tab
● Scheduling, see Operations Dialog: Scheduling Tab