DWSIM/C2/Calculation-of-Bubble-Points-and-Dew-Points/English

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Visual Cue Narration
Slide Number 1

Title Slide

Welcome to this tutorial on Calculation of Bubble Points and Dew Points in DWSIM.
Slide Number 2

Learning Objective

In this tutorial, we will learn to generate:


  • Bubble Point Temperature at a given pressure
  • Dew Point Temperature at a given pressure
Slide Number 3

System Requirements

To record this tutorial, I am using


  • DWSIM 5.2 and
  • Windows 10

The process demonstrated in this tutorial is identical in other OS also, such as-

  • Linux,
  • Mac OS X or
  • FOSSEE OS on ARM.
Slide Number 4

Pre-requisites

To practice this tutorial, you should know how to


  • Add components to a flowsheet
  • Select thermodynamic packages and
  • Add material stream and specify their properties.
Slide Number 5


Prerequisite Tutorials and Files

The prerequisite tutorials are mentioned on our website, spoken-tutorial.org


You can access these tutorials and all the associated files from this site.

Slide Number 6


Feed Conditions


Inlet Stream:


Mole Fraction(Methane): 0.05

Mole Fraction(Ethane): 0.1

Mole Fraction(Propane): 0.15

Mole Fraction(Isobutane): 0.1

Mole Fraction(N-butane): 0.2

Mole Fraction(Isopentane): 0.25

Mole Fraction(N-pentane): 0.15

Temperature: 25 degree C

Pressure: 5 bar


Property Package: Soave-Redlich-Kwong (SRK)

In this tutorial, using DWSIM, we will calculate:


1) Bubble Point Temperature at 2 bar

2) Dew Point Temperature at 10 bar


Here we provide the compounds, inlet stream conditions and property package.

I have already opened DWSIM on my machine.
File >>New Steady-state Simulation Go to File menu and select New Steady-state Simulation.
Point to Simulation Configuration Wizard window Simulation Configuration Wizard window appears.
Click on Next. At the bottom, click on the Next button.
Type Methane in the Search tab Now, in the Compounds Search tab, type Methane.
ChemSep database >>Methane Select Methane from ChemSep database.
Type Ethane in the Search tab Next, we will add Ethane.
Type Propane in the Search tab Similarly, add Propane.
Type Isobutane in the Search tab Next, add Isobutane.
Type N-butane in the Search tab Followed by N-butane.
Type Isopentane in the Search tab Similarly, add Isopentane.
Type N-pentane in the Search tab Then add N-pentane.
Click on Next. At the bottom of the window, click on the Next button.
Point to Property Packages The Property Packages opens.
Property Packages>>Available Property Package


Double click on Soave-Redlich-Kwong (SRK)

From Available Property Package list, double-click on Soave-Redlich-Kwong (SRK).
Click on Next button. Then click on the Next button.
Point to Flash Algorithm We are moved to a new window named Flash Algorithm.
Default Flash Algorithm >>Nested Loops (VLE) From Default Flash Algorithm select Nested Loops(VLE)
Click Next button. Click on the Next button at the bottom.
Point to System of Units The next option is System of Units.
System of Units >>C5 Under System of Units, select C5.
Click on Finish button. At the bottom, click on the Finish button.
Click on Maximize button. Let us maximize the simulation window for better visibility.
Cursor on the simulation window. Now let’s insert a material stream for which we have to calculate Bubble points and Dew points.
Point to Flowsheet Objects. On the right hand side of the main simulation window, go to Flowsheet Objects.
In the Filter List tab, type Material Stream In the Filter List tab, type Material Stream.
Click and drag Material Stream to the flowsheet From the displayed list, drag and drop a Material Stream to the Flowsheet.
Click on MSTR-000 Click on the Material Stream MSTR-000” to view its properties.
Type Feed Let’s change the name of this stream to Feed.
Now we will specify the Feed stream properties.
Input Data>>Flash Spec>>Temperature and Pressure(TP) Go to the Input Data.

Select Flash Spec as Temperature and Pressure (TP), if not already selected.

By default, Temperature and Pressure are already selected as Flash Spec.

Input Data >>Temperature >>25 degree C

Press Enter

Change Temperature to 25 degree Celsius and press Enter.
Input Data >>Pressure >>5bar

Press Enter

Change Pressure to 5 bar and press Enter.
Now let us specify the feed stream compositions.
Composition >>Basis >>Mole Fractions Under Composition, choose the Basis as Mole Fractions, if not already selected.

By default, Mole Fractions is selected as Basis.

Methane: 0.05 Now for Methane, type the Amount as 0.05 and press Enter.
Ethane: 0.1 For Ethane, type it as 0.1 and press Enter.
Propane: 0.15 Similarly, for Propane, type 0.15 and press Enter.
Isobutane: 0.1 And for Isobutane, type 0.1 and press Enter.
N-butane: 0.2 Next, for N-butane, type 0.2 and press Enter.
Isopentane: 0.25 For Isopentane, type 0.25 and press Enter.
N-pentane: 0.15 Lastly, for N-pentane, type 0.15 and press Enter.
Point to the tick.

Click Accept Changes

On the right, click on this green tick to Accept Changes.
Click on Utilities Now we will see how property package calculates phase equilibrium data of compounds.

To do this, go to Utilities.

Click on Add Utility Click on Add Utility.
Object Type >> Material Streams In the Add Utility window under Object Type, select Material Streams.
Utility Type >> Phase Envelope Under Utility Type, select Phase Envelope.
Flowsheet Object >> Feed Under Flowsheet Object, select Feed.
Click Add Utility Then click on Add Utility.
Point to Phase Envelope window. Phase Envelope window opens.
Drag the phase envelope window. Let us adjust the Phase Envelope window for better visibility.
Name >> BubblePoint-DewPoint Enter Name as BubblePoint-DewPoint.
Settings >> Bubble Points Under Settings, Click on Bubble Points Tab.
Point to Custom Initialization Check the check box against Custom Initialization.
Initial Flash >> PVF We are going to calculate bubble point temperature against given pressure.

So, let Initial Flash method be PVF.

Here, we will change only Initial Pressure and Pressure Step.

Initial Pressure >> 1 bar Type Initial Pressure as 1 bar and press Enter.
Pressure Step >> 1 bar Type Pressure Step as 1 bar and press Enter.
We will not change any temperature values as we are doing a PVF Flash.
Settings >> Dew Points Now, go to Dew Points tab.
We will repeat the same process as Bubble Points Initialization.
Point to Custom Initialization Check the check box against Custom Initialization.
Initial Flash >> PVF We are going to calculate dew point temperature against given pressure.

So, here also, let Initial Flash method be PVF.

Hence we will change only Initial Pressure and Pressure Step

Initial Pressure >> 1 bar Type Initial Pressure as 1 bar and press Enter.
Pressure Step >> 1 bar Type Pressure Step as 1 bar and press Enter.
Click on Calculate button at the bottom. Now click on the Calculate button at the bottom.
Point to the calculation process. The calculation process is running in the background.
Point to the dew points and bubble points. We can see the dew points and bubble points generated at different pressure and temperatures.
Results >> Table Under Results, click on Table.
Point to the Pb column>>2 bar

Point to the pressure value.

In the column Pb, look for 2 bar at which we had to calculate the bubble point.

Here is 2 bar under Pb column.

Point to the Tb column

Point to bubble point temperature value

Look for temperature in Tb column corresponding to 2 bar.

We can see the bubble point temperature to be minus 91.9274 degree C

Point 10 bar. Next we have to find Dew point temperature at 10 bar.
Point to the Pd column>> 10 bar.

Point to the pressure value.

In the column Pd, look for 10 bar at which we have to find the dew point.

Here is 10 bar under Pd column.

Point to the Td column

Point to dew point temperature value

Look for temperature in Td column corresponding to 10 bar.

We can see the dew point temperature to be 87.396 degree C.

There is an alternative way by which we can verify the correctness of above results.
For this, let’s get back to flowsheet window.
Click on Feed. Click on Feed.
Flash Spec >> Pressure and Vapor Fraction (PVF) Under Input data, select Flash Spec as Pressure and Vapor Fraction (PVF)
Pressure >> 2 bar Type Vapor Phase Mole Fraction as 0
Vapor Phase Mole Fraction >> 0 And Pressure as 2 bar.
Point to the temperature value.

Point to the bubble point temperature.

Now check the temperature which is minus 91.9274 degree C.

This is the bubble point temperature at 2 bar pressure.

It matches the value obtained earlier from Phase envelope.

Similarly, let’s check for Dew point temperature.
Flash Spec >> Pressure and Vapor Fraction (PVF) Let the Flash Spec be same as Pressure and Vapor Fraction (PVF)
Pressure >> 10 bar Type Vapor Phase Mole Fraction as 1
Vapor Phase Mole Fraction >> 1 And Pressure as 10 bar.
Point to the temperature value

Point to the bubble point temperature.

Now check the temperature which is 87.396 degree C.

This is the dew point temperature at 10 bar pressure.

It matches the value obtained earlier from Phase envelope.

Let's summarize.
Slide Number 7


Summary

In this tutorial, we have learnt to generate:


  • Bubble Point Temperature at a given pressure
  • Dew Point Temperature at a given pressure
Slide Number 8


Assignment


Feed Conditions


Mass Flow: 100 kmol/h

Mole Fraction(Ethanol): 0.6

Mole Fraction(Water): 0.4

Temperature: 30 degree C

Pressure: 3 bar


Property Package: Soave-Redlich-Kwong (SRK)

As an assignment, repeat these calculations with different compounds and inlet stream conditions.
Slide Number 9

About the Spoken Tutorial Project

Watch the video available at following link.

http://spoken-tutorial.org/

It summarizes the Spoken Tutorial project.

Slide Number 10

Spoken Tutorial Workshops

The Spoken Tutorial Project Team
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  • Gives certificates
  • For more details, please write to contact@spoken-tutorial.org
Slide Number 11


Forum Slide

Do you have questions in this Spoken Tutorial?

Please visit this site

Choose the minute and second where you have the question.

Explain your question briefly.

Someone from the FOSSEE team will answer them.

Please post your times queries in this forum.
Slide Number 12

DWSIM Flowsheeting Project

The FOSSEE team coordinates conversion of existing flow sheets into DWSIM.

We give honorarium and certificates.

For more details, please visit this site.

Slide Number 13

TextBook Companion Project

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Slide Number 14

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Slide Number 15

Acknowledgements

Spoken Tutorial and FOSSEE projects are funded by NMEICT, MHRD, Government of India.
Slide Number 16

Thanks

This tutorial is contributed by Kaushik Datta and Priyam Nayak.


Thanks for joining.

Contributors and Content Editors

Kaushik Datta, Nancyvarkey