Continuous Cooling Crystallization: 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

◙ Operating Temperature (°C) The temperature at which the crystallization takes place.	25.0	Positive
◙ Crystallization Yield (%) The crystallization yield of the reference component.	90.0	(0,100)
○ Operating Pressure Set by User? Check this box to set the operating pressure of the equipment.	No	Yes/No
◙ Pressure (atm) The operating pressure of the equipment.	1.0	Positive
○ Vacuum Pump Indicates the name of the engaged vacuum pump (a type of auxiliary equipment). Click on the list box to bring up a list of available vacuum pumps in order to select one.	<none>	Any Vacuum Pump
○ Vacuum Pump Power (kW) The power consumption of the engaged vacuum pump.	0.0	Positive
○ Operating Pressure Set by User? Check this box to set the operating pressure of the equipment.	No	Yes/No
◙ Pressure (atm) The operating pressure of the equipment.	1.0	Positive
● Inlet Temp. (^oC) The inlet temperature of the cooling agent.	5.0	Positive
● Cooling Duty (kcal/h) The cooling duty required.	0.0	Positive
○ Cooling Agent Name Indicates the cooling agent used for the operation. Click on the list box to bring up a list of available cooling agents in order to select one.	<Chilled Water>	Any Cooling Agent
● Inlet Temp. (^oC) The inlet temperature of the cooling agent.	5.0	Positive
● Outlet Temp. (^oC) The outlet temperature of the cooling agent.	10.0	Positive
● Rate (kcal/h) The heat transfer rate of the cooling agent.	0.0	Positive
○ Heat Transfer Efficiency(%) The heating agent consumption efficiency. Specify a value below 100% to account for heat losses to the surroundings when a heating agent is used.	100.0	[0,100)
● Crystallization Duty (kcal/h) The duty corresponding to the crystallization enthalpy(ies).	0.0	Positive
○ Power Type Indicates the power type that is used by the operation. Click on the list box to bring up a list of available power types in order to select one.	<Std Power>	Any Power Type
◙ Specific Power (Per Volume) (kW/m³) The power consumed for the operation per volume.	0.0	Positive
◙ Total Power (kW) The total power consumed for the operation (per cycle).	0.0	Positive
◙ Power Per Unit (kW) The power consumed for the operation per equipment unit.	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 Continuous Cooling Crystallization: Modeling Calculations.

•Crystal Formation...

This selection pertains to whether a single or multiple components are crystallized.

•Solubility Curve...

If the solubility curve is known (or can be deducted by available experimental measurements) then select the ‘Known’ option to incorporate a physical background into the calculations. Otherwise chose ‘Unknown’ in which case both the temperature and the design component crystallization yield must be specified.

•Pressure...

The pressure of the system, if not specified by the user, is set equal to the pressure of the input stream.

•Vacuum Pump Controls...

Note that the vacuum pump controls are only displayed if the operating pressure is less than the ambient pressure (specified through the flowsheet’s Reference Conditions dialog).

Click on the vacuum pump list box to bring up a list of available vacuum pumps in order to select one, or select “(none)” (default) if equipment sizing, costing and scheduling calculations are not important.

To create a new vacuum pump and add it to the list of available vacuum pumps, click on the New button (). This will open the Auxiliary Equipment Properties dialog for auxiliary equipment of the vacuum pump type (see Auxiliary Equipment Properties Dialog: Aux. Equipment tab (Vacuum Pump)). Through this dialog, you can view or edit the properties of the auxiliary equipment resource (e.g., name, size, purchase cost, consumables, scheduling).

The same dialog is displayed if you select one of the available vacuum pumps from the list and click on the View/Edit Properties button ().

Click on the Setup button to display the Vacuum Pump Consumption dialog (see Vacuum Pump Power Consumption Dialog), and select different options for specifying the power consumption of the vacuum pump. By default, the vacuum pump power specification option is “Set Total Power” and the total power consumption of the vacuum pump can be set by the user (the default value is zero). For more information, see Vacuum Pump Auxiliary Equipment Calculations.