Fed Batch Tab

Variable Definitions, Ranges and Default Values

The following table shows a brief description of the variables appearing in this tab. The table also displays their default values and their generally acceptable range:

Variable	Default Value	Range

○ Consider Fed-Batch Supply of Reactants Check this box to consider fed-batch supply of reactants.	No	Yes/No
○ Feed Stream Indicates the input stream that is used for fed-batch supply of reactants. Click on the list box to bring up a list of available input streams in order to select one.	<none>	Any Input Stream
○ Scalable Check this box to scale the fed-batch data.	Yes	Yes/No
○ Use Amount Available on Feed Stream Check this box to use the amount that is available on the feed stream.	No	Yes/No
◙ Mass (kg) The amount of material in the feed stream (in mass) per cycle.	0.0	Positive
◙ Volume (L) The amount of material in the feed stream (in volume) per cycle.	0.0	Positive
◙ Constant Mass Flow (kg/h) The mass flow rate of the feed stream.	0.0	Positive
◙ Constant Vol. Flow (L/h) The volumetric flow rate of the feed stream.	0.0	Positive
◙ Process Time (min) The actual duration of the operation.	60.0	Positive
● Key Reactant Concentration at Reaction Start (g/L) The concentration of a key reactant (that is desired to remain constant) at the start of the operation.	100.0	Positive

Symbol Key: ○ User-specified value (always input); ● Calculated value (always output); ◙ Sometimes input, sometimes output

Specification Choices / Comments

Specify whether there is simultaneous feed of material during the reaction, and select the feed stream. Then specify either the stream flowrate (mass/volume) or amount of material fed per cycle (mass/cycle) so that the flowrate is calculated. In all cases it is assumed that the feeding of material during the reaction is at a constant rate. The required flow of the feed stream is propagated backwards, through the network of connectivity.

If you check the ‘Scalable’ option, then the amounts you specify will be scaled with process throughput. That is if you choose to adjust the process throughput by a factor the user-specified flowrate or amount per cycle will also be adjusted by the same factor.

By selecting the Constant Reactant Concentration option the user can keep the concentration f a key reactant constant (equal to its initial value) by adjusting the flow rate of the fed-batch stream (variable feeding rate). This option is only available in batch kinetic reactions and fermentations.