Pasteurization: Oper. Conds Tab

PasteurizationOperConds.jpg
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

 

○ Pasteurization Temp. (°C)

72

Positive

○ Heat Transfer Coefficient (Watt/(m2-K))
Overall heat transfer coefficient of the heater.

2800

Positive

● Heating Duty (kcal/h)
The heat transfer rate of the heating agent.

0.0

Positive

○ Heating Agent Name
Indicates the heating agent that is used in the heater. Click on the list box to bring up a list of available heating agents in order to select one.

<Steam>

Any Heating Agent

● Heating Agent In Temp. (oC)
The inlet temperature of the heating agent.

152.0

Positive

● Heating Agent Out Temp. (oC)
The outlet temperature of the heating agent.

152.0

Positive

● Heating Agent 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)

○ Exit Temp. (oC)
The final exit temperature of the liquid from the pasteurizer.

8

Positive

○ Heat Transfer Coefficient (Watt/(m2-K))
Overall heat transfer coefficient of the cooler

2700

Positive

● Cooling Duty (kcal/h)
The heat transfer rate of the cooling agent.

0.0

Positive

○ Cooling Agent Name
Indicates the cooling agent used in the cooler. Click on the list box to bring up a list of available cooling agents in order to select one.

<Chilled Water>

Any Cooling Agent

● Cooling Agent In Temp. (oC)
The inlet temperature of the cooling agent.

5.0

Positive

● Cooling Agent Out Temp. (oC)
The outlet temperature of the cooling agent.

10.0

Positive

● Cooling Agent Rate (kg/h)
The mass flow rate of the cooling agent.

0.0

Positive

● Operating Throughput (m3/h)

0.0

Positive

○ 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).

240.0

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

◙ Reynolds Number
Reynolds number inside the holding tube.

12,000.0

Positive

○ Fluid Viscosity (cP)
Viscosity of the pasteurized fluid.

3.0

Positive

● Average Velocity (m/s)
Average velocity inside the holding tube.

0.0

Positive

○ Efficiency
The holding tube’s efficiency.

90%

0 - 99%

◙ Residence Time (min)
Average velocity inside the holding tube.

0.27

Positive

○ Heat Transfer Coefficient (Watt/(m2-K))
Overall heat transfer coefficient of the regenerator.

2.48

Positive

● Hot Stream exit Temp. (oC)
Exit temperature of the hot stream form the regenerator.

25.0

Positive

◙ Cold Stream exit Temp. (oC)
Exit temperature of the cold stream form the regenerator.

60.0

Positive

◙ Regenerator Efficiency

75%

0 - 99%

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

Specification Choices / Comments

In Design mode the model calculates the heat transfer areas of the heat exchangers and the volume of the holding tube. In Rating Mode, the Reynolds number and residence time in the holding tube are calculated by the model. For more details, see Pasteurization: Modeling Calculations.

•Duration Options...

In Design mode the user must specify the process time or match the duration of this operation to the duration of another operation by introducing a master-slave relationship. If you introduce a master-slave relationship, 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 details on how to setup a master-slave relationship, see The Scheduling Tab. In Rating Mode, the process time can either be specified or calculated based on the Throughput or the required Residence Time in the Holding Tube.