Flash Evaporation: Oper. Conds Tab

FlashOperConds.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

 

○ Feed Vaporization (% mol)

50.0

0 – 100

○ Component Vaporization (% mol)

0.0

0 – 100

○ Ref. Comp.
Indicates the component of the feed stream for which a reference component vaporization percentage is specified. Click on the list box to bring up a list of registered components in order to select one.

<None>

Any Pure Component

◙ (%) in Vapor Phase

0.0

0 – 100

○ Operating Temperature (C)

90.0

Positive

○ Operating Pressure (bar)

1.013

Positive

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

0.0

Positive

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

0.0

Positive

○ Agent Name
Indicates the heat transfer agent that is used by the operation. Click on the list box to bring up a list of available heat transfer agents in order to select one.

<Steam>

Any Heat Transfer Agent

● Inlet Temp. (oC)
The inlet temperature of the heat transfer agent.

152.0

Positive

● Outlet Temp. (oC)
The outlet temperature of the heat transfer agent.

152.0

Positive

● Rate (kg/h)
The mass flow rate of the heat transfer 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.

90.0

[0,100)

◙ Process Time (min)
The actual duration of the operation (per cycle).

60.0

Positive

● Operating Throughput (Per Unit) (m3/h)
The volumetric flow rate of the feed stream divided by the number of equipment units.

0.00

Positive

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

Specification Choices / Comments

•Vapor/Liquid Split...

You can set the vapor-liquid splits or let those be calculated by thermodynamic modeling (i.e., the  PS toolbox).

•Problem Specification...

In order to solve the system of equations eq. (A.273)- eq. (A.277), two variables need to be specified. In terms of flash problem specifications, the following flash problems are supported:

Flash Problem Type

Variables specified

 

 

Isothermal

T, P

Adiabatic

Q = 0, P

Feed vapor percentage

V/F, P

Component vapor percentage

yiV, P

•Process Time Options...

The process time controls appear only if the flowsheet and procedure are in batch mode. In Rating Mode, you can set the process time or allow the process time to be calculated based on the throughput. In Design mode, you must specify the process time.