This operation simulates a membrane washing step in bind-and-elute chromatography during which the membrane is washed with buffer in order to remove unwanted components retained in the system. The main objectives of this operation are to determine bufffer consumption and account for the release of retained mass from the membrane.
● Membrane Adsorption Procedure in Bind-and-Elute Mode
You need to specify the values of two out of the following three variables: buffer flowrate, buffer volume, and process time time. The value of the remaining variable will be calculated by the model as explained below.
If a buffer flowrate is set, you can specify any one of the following three variables: linear velocity, absolute flowrate, or relative flowrate. The other two variables will be calculated by the program according to the following equations:
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where ‘Bed Volume’ denotes the membrane’s volume in the context of this operation.
If a buffer flowrate is not set, then the absolute flowrate will be calculated by the program based on eq. (A.166).
If a buffer volume is set (per batch cycle and equipment unit), then you can either set an absolute volume or a relative volume (in membrane volumes). The buffer’s absolute volume is equal to its relative volume times the membrane’s volume. This relation is used to determine the absolute volume based on a relative volume, and vice versa. If a buffer volume is not set, then the absolute volume will be calculated by the program based on eq. (A.166).
The process time can be either set by user or calculated from the absolute values of buffer flowrate and volume as follows:
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where ‘Feed Volume’ denotes buffer volume in the context of this operation
The user must specify the buffer’s inlet and outlet (waste) stream ports and the inlet stream’s composition. The program will auto-adjust the total flow of the inlet stream (and, thereby, the flows of individual components in it) based on the buffer’s volume per batch cycle and per equipment unit.
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As far as the inlet stream is concerned, you only need to specify a valid composition for that stream and not worry about total stream flow (since the flowrate of the buffer’s inlet stream will be auto-adjusted by the program). |
All components of the buffer’s inlet stream end up in the buffer’s outlet (waste) stream. For each component, a percentage of the corresponding retained amount in the membrane equal to the specified release % for that component is also removed from the membrane and added to the buffer’s outlet (waste) stream.
The interface of this operation has the following tabs:
● Oper. Cond’s, see MA Wash: 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
