Stoichiometric Reaction/Fermentation Operation: Reactions Tab

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

● Reaction Name The name of the selected reaction.	Reaction #1	User Defined Text
○ Parallel? Check this box to specify that the selected reaction is a parallel reaction.	No	Yes/No
● Reaction-Limiting Comp. The name of the reaction-limiting component for the selected reaction.	<none>	Any Pure Component
● Reaction-Limiting Comp. Conversion Achieved (%) The fractional conversion of the reaction-limiting component.	0.0	0-100
◙ Conversion (%) The conversion based either on the reaction limiting component or on the selected reference component.	0.0	0-100
○ Ref. Comp. Indicates the pure component that is used as reference for specifying the conversion.	<none>	Any Pure Component
● Ref. Comp. Conversion Achieved (%) The maximum possible fractional conversion that can be achieved for the selected reference component.	0.0	0-100
◙ Target Concentration (g/L) The target concentration of a pure component.	0.0	Positive
○ Target Component Indicates the pure component that is used as reference for specifying a target concentration.	<none>	Any Pure Component
○ Unknown Reaction Heat Check this box to assume zero reaction heat at the enthalpy calculation reference temperature.	No	Yes/No
○ Enthalpy (kcal/kg) The specific enthalpy of the selected reaction.	0.0	Any Value
○ Reference Component The pure component that is used as reference for the enthalpy of the selected reaction.	<none>	Any Pure Component
○ Reference Temp. (^oC) The reference temperature of enthalpy of the selected reaction.	25.0	Positive

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

Specification Choices / Comments

The following list describes the available specification choices in this tab; for more details on how these are implemented, please view see Stoichiometric Reaction Operations: Modeling Calculations.

•Parallel Reaction...

You can select whether reactions occur in parallel or sequentially. For reactions taking place in parallel the specified reaction extent is applied to the material amounts as existing at the beginning of the parallel. Notice that, in order for a parallel scheme to be meaningful, all reactions should have at least one common component with another reaction. Otherwise, the parallel scheme specification will not be allowed by the program. Note that this option is not available in the case of the Continuous Stoichiometric Reaction in an Electrowinning Cell.

•Conversion...

It represents the fractional conversion of the limiting or reference component. The limiting component for each reaction is displayed under the reaction name. If the conversion is specified based on a reference component and its value is not feasible, the program will use the max possible value (corresponding to extent of 0 or 100%). The conversion achieved is displayed in the dialog.

•Target Concentration...

Instead of specifying the extent of reaction, you may specify the desired concentration of a reactant or product at the end of the reaction and the program will calculate the required extent. If the specified value is note feasible, the program will use the max possible value (corresponding to extent of 0 or 100%).

•Reaction Heat...

Use negative enthalpy values for exothermic (heat releasing) reactions and positive for endothermic (heat absorbing). You can either supply a value here at a given reference temperature and along with the assumed state of participants (see next), or you can invoke the Reaction Enthalpy Calculator by clicking on the button. This button will bring up the Reaction Enthalpy Calculator Dialog interface which allows you to estimate the reaction enthalpy (heat of reaction) based on the formation enthalpies its participant (reactants and products). Notice that you cannot invoke the Reaction Enthalpy Calculator if:

a) a reaction enthalpy reference component has not been selected or,

b) at least one reaction participant component is in the vapor phase at the enthalpy of formation reference temperature (i.e., its normal boiling point is below 25°C) and its vapor parameters have been declared to be ‘Unknown/Irrelevant’.

•Assumed PS of Reaction Participants

SuperPro offers the option to specify the physical state of the reaction participants (at the reaction reference temperature) that corresponds to the user-defined reaction enthalpy. By default, the physical states of the participating components are inferred by the normal boiling point criterion at the reaction reference temperature. Click on the button to view and edit the physical state of the reaction participants. Please see Reaction Participants PS Dialog.

•Reaction Sequence...

You can use the following buttons for editing / rearranging reactions:

to view/edit the reaction stoichiometry of the selected reaction

to delete the selected reaction,

to rename the selected reaction,

to insert a reaction above the selected one,

to add a reaction at the end of the sequence,

to move the selected reaction up in the sequence,

to move the selected reaction down in the sequence,

to move the selected reaction to the top of the sequence, and

to move the selected reaction to the bottom of the sequence.

If this Reactions tab is part of a Fermentation operation, and the user has defined a Primary Biomass component (see “Special Components”) and the chosen primary biomass component is being produced by any of the reactions listed in the scheme, two more controls appear on the dialog:

1. A drop-down for the selection of ‘Water’ component.

2. The primary biomass water content value (a percentage between (0-100)).

If a ‘Water’ component is chosen (from the list of registered components), then the reaction’s simulation will automatically transform enough quantity of the chosen ‘Water’ component as intracellular to indicate that the live cells ‘contain’ that amount of ‘Water’. This may be important for further processing of the reaction’s product stream as any downstream step separating the biomass cells, will automatically take with it ‘Water’ in proportion as dictated by the water’s intracellular percentage. If not enough ‘Water’ is present to be associated with the live biomass cells, a warning will be produced. If you don’t want the program to automatically make that association and determine the intracellular percentage of water needed to satisfy the primary biomass water content specification, simply leave the choice for ‘Water’ component as ‘(none)’.

If this Reactions tab is part of an Electrowinning operation (see Continuous Stoichiometric Reaction in an Electrowinning Cell), then the buttons for deleting, moving, adding or inserting a reaction will be disabled since that operation only allows one reaction to be specified.

For information on reaction stoichiometry, see Reaction Stoichiometry Balance Dialog and for information on bio-reaction stoichiometry, such as fermentation reactions, see Bio-Reaction Stoichiometry Balance Dialog.