Optimization Objective

Objective Function Weights

This view contains the list of variables you may use to build the objective function, whose formula is shown in a Preview Pane.
The variables are displayed in the following categories:

Yields : All Yields defined in the Yield Calculations node for compounds and conserved pseudocompounds are listed here.
Selectivities : All Selectivities defined in the Yield Calculations node for compounds and conserved pseudocompounds are listed here.
Conversions : All Conversions defined in the Yield Calculations node for compounds and conserved pseudocompounds are listed here.
Total Moles : It displays all compounds and conserved pseudocompounds available in the project, to allow the optimization of their Total Moles values at end of the operation time (for Batch reactor) or at the reactor outlet (for PFR or CSTR reactors). For more information on how pseudocompound total moles are calculated, please see here.
Total Mass : Available when Mass Density is selected as units of concentration in the Units Configuration node. It allows the optimization of the Total Mass values at end of the operation time (for Batch reactor) or at the reactor outlet (for PFR or CSTR reactors)
Values : It shows all non-conserved pseudocompounds and derived quantities available in the project. Thus, you can optimize their values at end of the operation time (for Batch reactor) or at the reactor outlet (for PFR or CSTR reactors).
Basic Variables : It lists variables like Time, Temperature, Flow, Catalyst Mass, Pressure, Volume or Specific Membrane Area depending on the reactor type. By adding weights for them, you can optimize their values at end of the operation time (for Batch reactor) or at the reactor outlet (for PFR or CSTR reactors).

You may enter the Weights for all the variables above, to build the objective function that has the following expression:

where:
w_Y,c are the weights for Y_c (Yield of compound or conserved pseudocompound c)
w_S,c are the weights for S_c (Selectivity of compound or conserved pseudocompound c)
w_C,c are the weights for C_c (Conversion of compound or conserved pseudocompound c)
w_TM,c are the weights for TM_c (Total Moles or Mass of compound or conserved pseudocompound c)
w_Val,c are the weights for Val_c (Values of derived quantity or non-conserved pseudocompound c)
w_Val,s are the weights for Val_s (Values of Basic Variables s)

You may maximize Yields, Selectivities, Total Moles or Mass, values of a given variable and Basic Variables by loading weights for them. Typically, you may use larger values for those variables that are more important. If a weight value is zero, that variable will not be taken into account in the optimization. A negative weight will have the effect of minimizing the corresponding variable.
When only one variable has nonzero weight, the results will be independent of the weighting factor (except for Pressure Control cases). In pressure control reactors, the weights loaded in this node and the Optimization → Weights → Values node for pressure (used to tune the controller) should be balanced to get the desired objective.