Custom Mixing: Oper. Conds 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

◙ Input Ratio Based On Mass The ratio of the mass of the mix-in (top) stream to the mass of the process (bottom) stream.	0.0	Positive
◙ Input Ratio Based On Volume The ratio of the volume of the mix-in (top) stream to the volume of the process (bottom) stream.	0.0	Positive
○ Mix-in Amount Reference Component Indicates the component that corresponds to the nominator of the specified mass or volume ratio. Click on the list box to bring up a list of registered components in order to select one.	<None>	Any Pure Component
○ Process Amount Reference Component Indicates the component that corresponds to the denominator of the specified mass or volume ratio. Click on the list box to bring up a list of registered components in order to select one.	<None>	Any Pure Component
◙ Output Temperature (^oC) The temperature of the mixture.	25.0	Positive
○ Scalable Output Flow Check this box to scale the flow of the mixture.	Yes	Yes/No
◙ Output Mass Flow (kg/h or kg/batch) The mass flow of the mixture.	0.0	Positive
◙ Output Volume Flow (L/h or L/batch) The volumetric flow of the mixture.	0.0	Positive
○ Max Number of Iterations (Set Output Flow Option) If the output volume flow is set, an iterative solution algorithm is employed in order to determine the flow of the mix-in stream. The maximum number of iterations corresponds to the maximum number of times that this algorithm can be repeated till it reaches convergence.	1000	Positive Integer
○ Relative Error (Set Output Flow Option) If the output volume flow is set, an iterative solution algorithm is employed in order to determine the flow of the mix-in stream. The relative error of the solution algorithm is defined in terms of the specified (V) and calculated (V) output volume flows as \|1- V/V\|. The solution is considered to have reached convergence if the calculated relative error is less than or equal to the specified value.	0.00001	Positive
○ Output Composition Reference Component Indicates the design component whose composition in the mixture is specified. Click on the list box to bring up a list of registered components in order to select one.	<None>	Any Pure Component
○ Output Component Mass % The mass% of the selected component in the output stream.	0.0	0 – 100
○ Output Component Concentration (g/L) The concentration of the selected component in the output stream.	0.0	Positive
○ Max Number of Iterations If the output composition for a selected component is set, an iterative solution algorithm is employed in order to determine the flow of the mix-in stream. The maximum number of iterations corresponds to the maximum number of times that this algorithm can be repeated till it reaches convergence.	1000	Positive Integer
○ Relative Error If the output composition for a selected component is set, an iterative solution algorithm is employed in order to determine the flow of the mix-in stream. The relative error of the solution algorithm is defined in terms of the specified (C) and calculated (C) component output concentration as \|1- C/C\|. The solution is considered to have reached convergence if the calculated relative error is less than or equal to the specified value.	0.00001	Positive
● Mix-in (Adjustable) Stream Indicates the name of the input stream that is connected to the mix-in (top) input port. If an input stream is already present at that port, then the button next to the selection is active. Click on the button to bring up the attached stream’s simulation dialog in order to provide the composition of the material being charged.	<None>	Dedicated Input Port
○ Setup Time (min) The amount of time (per cycle) spent before each operation is carried in preparation for the actual execution of the operation. It may involve actions like cleaning, vacuuming, setting up of equipment, etc. which the user opted not to model explicitly.	0.0	Positive
◙ Process Time (min) The actual duration of the operation (per cycle).	60.0	Positive
○ Ignore Labor? Check this box to ignore labor for this operation. This option is used only if the process time is set by a master-slave relationship.	Yes	Yes/No
● Operating Throughput per Unit (kg/h) The mass flow rate of the mixture in the equipment.	0.0	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, see Custom Mixing: Modeling Calculations.

•Mixing specifications...

Select one of the following mixing specifications:

a) Set Input Ratio (Mix-in Amount /Process Stream): In this case you can specify either the mass ratio or the volume ratio between the mix-in and the process stream. Furthermore you can ask the numerator of the ratio to be either the mass/volume of the total stream or just one (user-selected) component in the mix-in stream. In the same spirit, the denominator used to calculate the specified ratio, may be either the total mass (or volume) of the process stream or the mass (or volume) of a specific (user-selected) component in that stream.

b) Set Output Flow: In this case you can specify either the mass flow or the volume flow of the output stream.

c) Set Output Temperature: In this case you set the temperature of the output stream.

d) Set Output Composition for Component: In this case you specify a reference component and either its outlet concentration or its outlet mass percentage.

e) Output Flow Set by Process: In this case the flow of the output stream is specified by a downstream process.

The model will set the mass flowrate of the adjustable mix-in inlet stream (top stream) in order to meet the mixing specification set by the user. If the mixing specification cannot be met, then a warning message will be displayed during simulation.

•Operating Throughput per Unit...

The operating throughput per unit is based on the mass flowrate of the output stream.

•Scalable Output Flow...

If the selected mixing specification is to set the output flow, specify whether that is scalable with process throughput adjustment. (This implies that if the user chooses to adjust the process throughput by a factor the output flow will also be adjusted by the same factor.)

•Time Reference...

Choose the time reference for flowrate. The flowrate can be specified by the user to be per Batch, per Cycle, or per Time Average. Depending on whether the procedure is in batch mode or continuous, and the whether process is in batch mode or continuous, certain options may not be available. Specifically the availability of time reference flows depending on the mode of procedure / process is:

Process Mode	Procedure Mode	Time Reference for Flow

Batch	Batch	Batch / Cycle
Batch	Continuous	Batch / Time Average
Continuous	Continuous	Time Average
Continuous	Batch	Cycle / Time Average

•Duration Options...

The duration controls appear only if the procedure is in batch mode. In Rating Mode, you can set the process time (and the setup time), allow the process time to be calculated (based on the throughput of the units), or allow the duration to match exactly the duration of another operation either in the same procedure or in another procedure. In Design mode, you must either specify the process time (and the setup time) or allow the duration to match exactly the duration of another operation (either in the same procedure or in another procedure).

If you choose to match the duration of this operation with the duration of another operation, you introduce a master-slave relationship between the two operations. The program will match the setup-time, the process time and the turnaround time of this operation (the ‘slave’) with the corresponding times of the reference operation (the ‘master’ operation). For more on master-slave relationship, see The Scheduling Tab.