DWSIM/C2/Shortcut-Distillation/English

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Visual Cue Narration
Slide Number 1

Title Slide

Welcome to this tutorial on Simulating a Shortcut Distillation column in DWSIM.
Slide Number 2


Learning Objectives

In this tutorial, we will learn to:
  • Simulate a Shortcut distillation column
  • Calculate Minimum number of stages
  • Calculate Minimum reflux ratio
  • Calculate Optimal Feed stage location
  • Calculate Condenser and Reboiler duty
Slide Number 3

System Requirements

This tutorial is recorded using
  • DWSIM version 5. 8 (Classic UI) Update 3
  • Windows 10 OS

But, this process is identical in Linux, Mac OS X or FOSSEE OS on ARM.

Slide Number 4

Prerequisites

To practise this tutorial, you should know to-
  • Add components to a flowsheet
  • Select thermodynamic packages
  • Add material and energy streams and specify their properties.
Slide Number 5

Prerequisite Tutorials and Files

https:\\spoken-tutorial.org

The prerequisite DWSIM tutorials are available on this website.

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

Slide Number 6

Compounds: Benzene & Toluene

Thermodynamics: Raoult’s Law

Inlet Stream:

Flow Rate: 100 Kmol/h

Pressure: 1 atm

Mole Fractions:

Benzene = 0.4, Toluene = 0.6

Method: Fenske-Underwood-Gilliland

We will develop a flowsheet to determine Outlet stream properties after Shortcut Distillation.

Here we give Compounds, Thermodynamics and Inlet stream conditions.

Slide Number 7

Column Properties

Reflux Ratio: 1.4 times minimum reflux ratio.

Product:

Light: Benzene, Heavy: Toluene

Distillate: XD = 0.99

Bottams: XB = 0.01

Next, we give Shortcut Column Properties.
Switch to DWSIM. I have already opened DWSIM.
File >> New Steady-state Simulation Go to File menu and select New Steady-state Simulation.
Cursor to Simulation Configuration Wizard window Simulation Configuration Wizard window opens.
Click on Next button at the bottom. Click on Next button at the bottom.
Type Benzene in the search tab In the Compounds Search tab, type Benzene.
ChemSep database >> Benzene Select Benzene from ChemSep database.
Type Toluene in the Search tab Similarly, add Toluene.
At the bottom, Click on Next. Click the Next button at the bottom.
Point to Property Packages Now comes Property Packages.
Property Packages >> Available Property Package

Double click on Raoult’s Law

From Available Property Packages list, double-click on Raoult’s Law.
At the bottom, Click on the Next button. At the bottom, click on the Next button.
Point to System of Units Next option is System of Units.
System of Units >> C5 Under System of Units, select C5.
Click Pressure and choose atm Pressure menu appears at the top of this list.

Select atm for atmosphere and press Enter.

Click on Finish Lastly, at the bottom, click on the Finish button.
Now maximize the Simulation window.
Click and drag Material Stream to the flowsheet Now let’s insert a feed stream that has to be distilled.
Point to Streams. At the bottom of the main simulation window, go to Streams.
Click and drag Material Stream to the flowsheet From the displayed list, drag and drop a Material Stream to the Flowsheet.
Click MSTR-000 Click on the material stream named MSTR-000.
Type Feed

Press Enter.

Let’s change the name of this stream to Feed.

Press Enter.

Now we will specify the Feed stream compositions.
Input Data >> Compound Amounts For this under Input Data click on Compound Amounts tab.
Basis >> Mole Fractions Choose the Basis as Mole Fractions, if not already selected.

By default, Mole Fractions is already selected as Basis.

Benzene: 0.4 and press Enter. For Benzene enter 0.4 and press Enter.
Toluene: 0.6 and press Enter. For Toluene enter 0.6 and press Enter.
Click Accept Changes button On the right, click on the Accept Changes button.
Now we will specify the Feed stream properties.
Go to Input Data.

Stream Conditions >> Flash Spec >> Pressure and Vapor Fraction. (PVF)

Go to Input Data.

Under Stream Conditions tab, select Flash Spec as Pressure and Vapor Fraction. (PVF)

Change Pressure Change Pressure to 1 atm and press Enter.
Click Molar flow Change Molar flow to 100 Kmol/h and press Enter.
Click Vapor Phase Mole Fraction Now locate Vapor Phase Mole Fraction.

Here the default value is 0.

This indicates that the liquid is saturated.

Let us leave it as it is.

Now let us insert a Shortcut Column into the flowsheet.
Click and drag Shortcut column to the flowsheet At the bottom of the main simulation window, go to Columns tab.

The Shortcut Column is based on Fenske-Underwood-Gilliland method.

Click and drag Shortcut Column to the flowsheet From the displayed list, drag and drop a Shortcut Column to the Flowsheet
Now let us insert two output streams.
Click and Drag Material Stream to the flowsheet To do that, let us drag one Material Stream.
Leave that stream as unspecified.
Type Distillate Then we will change the name of this stream to Distillate.
Click and drag Material Stream to the flowsheet Next, we will insert another Material Stream.
Leave that stream as unspecified.
Type Bottoms

Press Enter.

Let us change the name of this stream to Bottoms.

Press Enter.

Click and drag Energy Streams to the flowsheet Let us now insert two Energy streams for Condenser duty and Reboiler duty.
Click and drag material stream to flowsheet Go to Streams tab.

From the displayed list, drag and drop two Energy Streams to the Flowsheet.

Let us now arrange it as required.
Click on stream.

Go to the Property Editor Window

Type C-Duty and R-Duty

Name these streams as C-Duty and R-Duty.
Click Shortcut distillation column We are now ready to specify the Shortcut distillation column.

So let’s click on it.

Point to the tab on the left. On the left, we can see a tab displaying properties related to the Shortcut Column.
Go to Connections

Click on drop down arrow against Feed Stream

Select Feed.

Under Connections, click on the drop-down against Feed Stream.

Select Feed.

Click on drop down arrow against Distillate Stream

Select Distillate.

Click on the drop-down against Distillate Stream and select Distillate.
Click on drop down arrow against Bottoms Stream

Select Bottoms.

Click on the drop-down against Bottoms Stream and select Bottoms.
Click on drop down arrow against Condenser Duty

Select C-Duty.

Click on the drop-down against Condenser Duty and select C-Duty.
Click on drop down arrow against Reboiler Duty

Select R-Duty.

Click on the drop-down against Reboiler Duty and select R-Duty.
This completes the connectivity of the flowsheet.
Point to Calculation Parameters Now, go to the Calculation Parameters.

This section is used to specify various attributes of a Shortcut Column.

Click on drop down arrow against Light Key Compound (LK)

Select Benzene.

Click on the drop-down against Light Key Compound (LK) and select Benzene.
Click on drop down arrow against Heavy Key Compound (HK)

Select Toluene.

Click on the drop-down against Heavy Key Compound (HK) and select Toluene.
Hover mouse at Properties, Parameters, Condenser type Now go to Condenser Type.

By default, it is Total Condenser.

If a partial condenser is required, we can change it here.

LK Mole Fraction in Bottoms >> 0.01

Press Enter

Click on the field against LK Mole Fraction in Bottoms and enter it as 0.01 and press Enter.
HK Mole Fraction in Distillate >> 0.01

Press Enter

Click on the field against HK Mole Fraction in Distillate and enter it as 0.01

Then press Enter.

Let us go back to the slides.
Show Slide

Highlight 1.4

Recall that we want our reflux ratio to be 1.4 times the minimum reflux ratio.

So let us check the minimum reflux ratio.

For this, let us run simulation once.
Click Solve Flowsheet To do this, click on Solve Flowsheet button.
Click on the Distillation Column.
From the Property Editor Window, locate Results section.
Results >> Minimum Reflux Ratio

Actual Reflux Ratio = 1.655*1.4 = 2.317

Now we can see that Minimum Reflux Ratio is 1.655.

So the actual Reflux Ratio will become 2.317.

Hover mouse at Results >> Actual Number of Stages, Optimal Feed Stage Next let us enter the reflux ratio.

Look at the Shortcut Column results.

Here note the Actual Number of Stages and Optimal Feed Stage.

We can see that these values are NaN.

This is because the default value of reflux ratio is 1.5.

It is less than minimum reflux ratio.

Reflux Ratio >> 1.655*1.4 and ress Enter

Reflux Ratio: 2.317

Now let us enter the Reflux Ratio.

Enter the value as 1.655*1.4 and press Enter.

Now the Reflux Ratio is 2.317.

Condenser Pressure >> 1 atm

Press Enter

Click on the field against Condenser Pressure and enter it as 1 atm

and press Enter.

Reboiler Pressure >> 1 atm

Press Enter

Click on the field against Reboiler Pressure and enter it as 1 atm .

Then press Enter.

Now we will run the simulation.
Click Solve Flowsheet To do this, click on the Solve Flowsheet button on the toolbar.
Click on the Shortcut column When calculations are completed, click on the Shortcut column.
Hover mouse at Properties, Results From the Property Editor Window, locate Results section.

This shows the all required results like:

Minimum Reflux Ratio

Minimum Number of Stages

Actual Number of Stages

Optimal Feed Stage

Condenser Duty, Reboiler Duty, etc

Slide Number 8

Results

I have tabulated these results in a slide.
Let us go back to the simulation.
Click File and Save As >> File name = shortcut-end Let me save this.

I will save it as shortcut-end.

Let's summarize.
Slide Number 9

Summary

In this tutorial, we have learnt to:
  • Simulate a Shortcut distillation column
  • Calculate Minimum number of stages
  • Calculate Minimum reflux ratio
  • Calculate Optimal Feed stage location
  • Calculate Condenser and Reboiler duty
Slide Number 10

Compounds: Ethanol & Water

Thermodynamics: Raoult’s Law

Inlet Stream:

Flow Rate: 100 kmol/h

Pressure: 1 atm

Mole Fractions:

Ethanol = 0.5, Water = 0.5

Method: Fenske-Underwood-Gilliland

As an assignment,

Repeat this simulation with different compounds.

Different feed conditions.

Slide Number 11

Column Properties

Reflux Ratio: 1.5 times the minimum reflux ratio.

Product:

Light: Ethanol, Heavy: Water

Distillate: XD = 0.99

Bottams: XB = 0.01

Different Column Properties.
This brings us to the end of this tutorial.
Slide Number 12

About the Spoken Tutorial Project

Watch the video available at the following link.

http://spoken-tutorial.org/

It summarizes the Spoken Tutorial project.

Slide Number 13

Spoken Tutorial Workshops

The Spoken Tutorial Project Team
  • Conducts workshops and
  • Gives certificates.
  • For more details, please write to us.
Slide Number 14

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 time queries in this forum.
Slide Number 15

DWSIM Flowsheeting Project

The FOSSEE team coordinates conversion of existing flowsheets into DWSIM.

We give honorarium and certificates for those who do this.

For more details, please visit this site.

Slide Number 16

Lab Migration Project

The FOSSEE team helps migrate commercial simulator labs to DWSIM.

We give honorarium and certificates for those who do this.

For more details, please visit this site

Slide Number 17

Acknowledgements

Spoken Tutorial and FOSSEE projects are funded by NMEICT, MHRD, Government of India.
Slide Number 18

Thanks

We thank the DWSIM team for making it as an open source software.

This tutorial was originally recorded by Prof Kannan Moudgalya in May 2015.

This is Kaushik Datta from IIT Bombay.

Thanks for joining.

Contributors and Content Editors

Kaushik Datta, Nancyvarkey