Dead-end filtration is usually a polishing step after centrifugation or before a chromatography unit. The filter medium is usually mounted on a cartridge that is replaced periodically.
● Dead End Filtration Procedure
The material balances are based on the removal percentage of particulate components and the cake dryness (Particle Conc. in Retentate). The removal percentage is either specified by the user or calculated by the program based on the filter medium pore size (0.45 microns by default). The removal percentage of particulate components determines the amount of those components that is retained by the filter. The cake dryness (Particle Conc. in Retentate) expressed in v/v, determines the amount of solvent and soluble components retained in the retentate.
In design mode of calculation, the process (filtration) time (tp) is specified by the user and the filter area (A) is calculated using the following equation:
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where Vslurry is the volume of slurry processed per batch, Ncycles is the number of cycles per batch, and J is the average filtrate flux. If the process operating mode is batch and the filtrate volume per area is set, then the average filtrate flux is calculated by dividing the filtrate volume per area by the process time. Otherwise, the filtrate volume per area is calculated by multiplying the average filtrate flux by the process time. If the calculated filter area exceeds the maximum that the user specifies, the program automatically assumes multiple units of equal size with a total filter area equal to the calculated.
In rating mode, the user specifies the filter area and the number of units and the program calculates either the average filtrate flux (when the filtration time is specified) or the filtration time (when the flux is specified). The filtrate volume per area is then calculated by multiplying the average filtrate flux by the process time.
The cost associated with the periodic replacement of the cartridges contributes to cost of Consumables. This cost is calculated based on the replacement frequency (in Operating Hours or Number of Cycles), the cartridge cost (in $/cartridge or $/m2 fitter area), and the filtration time (specified by the user or calculated by the program).
The interface of this operation has the following tabs:
● Oper. Cond’s, see Dead End Filtration: Oper. Conds 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