Rotary Drying: Oper. Conds Tab

This tab appears on the interface data dialogs of the following operations:

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

○ Heat the Feed Using Heating Gas? Check the box to simulate heating (and drying) of the feed stream using a heating gas in the dryer’s heating section. If this option is checked you must add heating gas i/o streams using the designated heating gas i/o ports (hover the mouse pointer over a input or output port to display a description for that port). Also, if this option is checked, the “Heating” tab is displayed on the operation’s data dialog.	<No>	Yes/No
○ Use Heating Agent to Preheat the Gas? Check the box to simulate preheating of heating gas using a heating agent.	<No>	Yes/No
○ Hot Gas Temperature (°C) The temperature of heating gas after preheating.	150.0	Positive
○ Perform Liquid Phase Reaction Calculations? Check the box to perform one or more liquid phase reactions on the hot product isothermally (at the specified hot product temperature) . If this box is checked, the “Reactions” tab is displayed on the operation’s data dialog.	<No>	Yes/No
○ Radiation Losses (% of Total Heat Input) The heat losses to the vessel’s walls and surroundings expressed as a percentage of the total heat input (which is the sum of sensitive enthalpies of input streams and reaction enthalpies).	0.0	0-100
○ Cool Down the Hot Feed Using Cooling Gas? Check the box to simulate cooling (and drying) of the feed stream (or of the feed stream after heating, if the option to heat the feed using heating gas is also checked) using a cooling gas in the cooling section. If this option is checked you must add cooling gas i/o streams using the designated i/o ports (hover the mouse pointer over a input or output port to display a description for that port). Also, if this option is checked, the “Cooling” tab is displayed on the operation’s data dialog.	<No>	Yes/No
○ Heating Agent Name Indicates the heating agent used for the operation. Click on the list box to bring up a list of available heating agents in order to select one.	<Steam>	Any Heating Agent
● Inlet Temperature (^oC) The inlet temperature of the heating agent.	152.0	Positive
● Outlet Temperature (^oC) The outlet temperature of the heating agent.	152.0	Positive
● Duty (kcal/h) The heating duty (i.e., the heat transfer rate from the heating agent to the heating gas inlet stream).	0.0	Positive
● Rate (kg/h) The mass flow rate of the heating 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)
◙ Specific Evaporation Rate (kg/m³-h) The mass flow rate of evaporating components per unit vessel volume.	20.0	Positive
◙ Specific Feed Rate (kg/m³-h) The mass flow rate of feed stream components per unit vessel volume.	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 (kW/m² of vessel area) The power consumed for the operation per unit vessel area.	0.0	Positive
◙ Power (kW) The total power consumed for the operation (per cycle, if the procedure operating mode is set to batch).	0.0	Positive
◙ Power Per Unit (kW) The power consumed for the operation per equipment unit (and per cycle, if the procedure operating mode is set to batch).	0.0	Positive
○ Pressure Set by User Check this box to set the pressure.	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
○ Setup Time 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
● Drying Time (h) The actual duration of the operation (per cycle).	6.0	Positive
◙ Vacuum Pump Power (kW) The power consumption of the vacuum pump used to evacuate the gas when the operating pressure is lower than the ambient pressure. Note that this parameter is available only when the operating pressure setting is lower than the ambient pressure setting (which is defined at the flowsheet level).	0.0	Positive
● Drying Gas Inlet Stream Indicates the input port that is connected to the drying gas inlet stream. If an input stream is already present at the selected 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

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 Rotary Drying: Modeling Calculations.

•Heating/Cooling Options...

If the “Heat the Feed Using Heating Gas” option is checked, the Heating Gas In Stream will be used to heat and dry the wet feed stream. If the Heating Gas In Stream is not preheated already, you may check the option “Use Heating Agent to Preheat the Gas” to simulate preheating using a suitable heating agent. In that case, you must select a suitable heating agent and you must also specify the temperature of the heating gas stream after preheating (“Hot Gas Temp.”). Also, if the “Heat the Feed Using Heating Gas” option is checked, the “Heating” tab will appear on the operation’s data dialog. Through this tab you may specify the inlet gas flow requirement, component evaporation data, solids entrainment data, and the temperature of the product stream after heating. In addition, if this option is checked, you must add a Heating Gas In stream and a Heating Gas Out stream (hover the mouse pointer over the procedure icon’s i/o ports to find the “Heating Gas In” and “Heating Gas Out” ports). Moreover, if you check the option “Perform Liquid Phase Reaction Calculations”, the “Reactions” tab will appear. Through this tab, you can specify one or more reactions to be performed on the dried product isothermally (at the specified hot product temperature).

If the “Cool Down the Hot Feed Using Cooling Gas” option is checked, the Cooling Gas In Stream will be used to cool down and dry either the wet feed stream (if the “Heat the Feed Using Heating Gas” option is not checked) or the dried feed stream (if the “Heat the Feed Using Heating Gas” option is checked). In other words, if both the “Heat the Feed Using Heating Gas” and “Cool Down the Hot Feed Using Cooling Gas” options are checked, the wet feed stream will be heated first using a heating gas stream, and then it will be cooled down using a cooling gas stream. If the “Cool Down the Hot Feed Using Cooling Gas” option is checked, the “Cooling” tab, which is similar to the “Heating” tab, will appear on the operation’s data dialog.In addition, if this option is checked, you must add a Cooling Gas In stream and a Cooling Gas Out stream (hover the mouse pointer over the procedure icon’s i/o ports to find the “Cooling Gas In” and “Cooling Gas Out” ports).

•Sizing/Rating Options...

Two options are available for sizing in design mode: you may size the equipment either based on specific evaporation rate (default) or based on specific feed mass flow rate. In the latter case, you do not need to set component evaporation percentages through the “Heating” tab or through the “Cooling” tab (i.e., the evaporation can be assumed zero). This can be useful, e..g, if you want to simulate cooling and the evaporation during cooling is not significant.

If the process operating mode and procedure operating mode are set to batch, then: if the equipment is in design mode you must specify one of the two sizing/rating options available (either the specific evaporation rate or the specific feed rate); if the equipment is in rating mode, you can either specify the drying time or one of the above sizing/rating options.

If the process operating mode or procedure operating mode is continuous, then: if the equipment is in design mode, you must specify one of the two above sizing/rating options; if the equipment is in rating mode, the specific evaporation rate and specific feed rate will be calculated by the program.

•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.

•Duration Options...

The duration options are only displayed if the procedure operating mode is set to batch. If the process operating mode is also batch and the equipment is in rating mode, you can either specify the drying time or the specific evaporation rate. If the process operating mode is continuous or the equipment is in design mode, you must specify the drying time.