Mixing & drying is used for the mixing & drying of solids and pastes in a double cone dryer, cone screw dryer or sphere dryer operating in batch mode. Frequent applications include drying of valuable products in the pharmaceutical, chemical and food industry. The advantage of this operation over the tray drying operation is that the drying, homogenizing and storing steps in a vessel are combined in one method (instead of using a dryer and silo), reducing labor requirement and contamination risks. In addition the simultaneous stirring / agitation can reduce the drying batch time.
● Double Cone Drying Procedure
The material balances are done based on the evaporation percentage of the solvent components. The specific heating requirement along with the amount of solvents that evaporate are used to calculate the total heating requirement. The specific power requirement is used to calculate the overall power requirement. The Drying Gas Requirement along with the amount of solvents that evaporate is used to calculate and adjust the flowrate of the drying gas.
The equipment is sized based on its volume. In Design Mode, the user specifies the maximum equipment volume and the maximum allowable working to vessel volume. The user specified Final Solids Bulk Density is used to calculate the dried solids volume (working volume). If calculated volume exceeds the maximum allowable per unit, the program assumes multiple identical units operating in parallel with a total tray area equal to the calculated. In Rating Mode, the user specifies the number of parallel units their volume, and the maximum allowable working to vessel volume. If the calculated working volume exceeds the maximum allowable value, the user is warned.
The drying time is either specified by the user or calculated based on the evaporation rate (in kg evap./h).
See Vacuum Pump Auxiliary Equipment Calculations.
The interface of this operation has the following tabs:
● Oper. Cond’s, see Mixing & Drying: Oper. Conds Tab
● Volumes, see Mixing & Drying Operations: Volumes Tab
● Utility Data, see Drying Operations: 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