Column Flush

General Description

This operation simulates a column flushing/pre-conditioning step in flow-through and bind-and-elute chromatographies. During this step the column is flushed with buffer in order to remove contaminants. The main objective of this operation is to determine buffer consumption. Any change that may occur in the column’s retained mass during this step (such as the removal of contaminants) is ignored.

Unit Procedure Availability

      Packed Bed Adsorption (PBA) Chromatography Procedure (Detailed) in Bind-and-Elute Mode

      Packed Bed Adsorption (PBA) Chromatography Procedure (Detailed) in Flow-Through Mode

Column Flush: Modeling Calculations

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.

Process Time

The process time can be either set by user or calculated based on the buffer volume and flowrate as follows:

ColumnFeedProcessTime00628.jpg 

eq. (A.166)

where ‘Feed Volume’ denotes the buffer volume in the context of this operation. If the process time is set by user then the above equation is used to calculate either the buffer flowrate (if the buffer volume is set) or the buffer volume (if the buffer flowrate is set).

Buffer Flowrate

If the process time is set and the buffer flowrate is set, or if the process time is calculated, 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:

ColumnFeedFlowAbs00631.jpg 

eq. (A.163)

ColumnFeedFlowRel00634.jpg 

eq. (A.164)

If the process time is set, the above two equations are used to calculate the linear velocity and relative flowrate, respectively.

Buffer Volume

If the process time is set and the buffer volume is set, or if the process time is calculated, then you can either set the absolute buffer volume (per batch cycle and equipment unit) or the relative buffer volume (in bed volumes). The buffer’s absolute volume is equal to its relative volume times the bed volume. This relation is used to determine the absolute volume based on a relative volume, and vice versa.

Inlet Stream Flow

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.

IconInfo00637.bmp 

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).

Material Balances

All components of the buffer’s inlet stream end up in the buffer’s outlet (waste) stream.

Column Flush: Interface

The interface of this operation has the following tabs:

      Oper. Cond’s, see Column Flush: 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