DWSIM/C2/Gibbs-Reactor/English

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Visual Cue Narration
Slide Number 1

Title Slide

Welcome to this tutorial on simulating a Gibbs Reactor in DWSIM.
Slide Number 2

Learning Objective

In this tutorial, we will learn to:
  • Simulate a Gibbs Reactor
  • Use different Minimization Methods
  • Calculate Conversion percentage and Reaction extent
  • Compare Equilibrium and Gibbs Reactor values
Slide Number 3

System Requirements

To record this tutorial, I am using
  • DWSIM 5.2 (Classic UI) update 22 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 to-
  • Add components to a flowsheet
  • Select thermodynamic packages
  • Add material and energy streams and specify their properties
Slide:

Prerequisite Tutorials and Files

www.spoken-tutorial.org

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 5


Reaction and Inlet Condition


Reaction:

CO (g) + H2O (g) ⇔ H2 (g) + CO2 (g)


Inlet Stream:


Mass Flow: 3600 kg/h

Mole Fraction(CO): 0.5

Mole Fraction(H2O): 0.5

Mole Fraction(H2): 0

Mole Fraction(CO2): 0

Temperature: 25 degree C

Pressure: 1.01325 bar

Here we can see the problem statement of the earlier tutorial.

Slide Number 6

Property Package: Raoult’s Law

Reaction Temperature: 225 degree C

This was solved using Equilibrium Reactor.
Cursor on the DWSIM interface.

Cursor on Equilibrium_reactor. dwxmz file.

Let us open the corresponding file in DWSIM.

I have already opened DWSIM on my machine.

I have already opened Equilibrium_reactor. dwxmz file.

This file can also be downloaded from the Code files link.

Save As >> Gibbs_reactor. Let me save this as Gibbs_reactor.

You can see that the file name has changed now to Gibbs_reactor.

Point to Gibbs Reactor. We will solve the same problem using Gibbs Reactor as solved in Equilibrium Reactor.

And compare results with that solved in Equilibrium Reactor.

Right click on Equilibrium Reactor >> Delete Let us begin by replacing the Equilibrium Reactor with a Gibbs Reactor.

Right click on the Equilibrium Reactor and select Delete.

Delete Equilibrium Reactor >> Yes Click Yes to the prompt Delete Equilibrium Reactor.
Now let us insert a Gibbs Reactor into the flowsheet.
Go to Flowsheet Objects>>Filter List tab

Click and drag Gibbs Reactor to the flowsheet

Go to Flowsheet Objects.

In the Filter List tab, type Gibbs Reactor.

Drag and drop it to the flowsheet in the place of Equilibrium Reactor.

Let us now arrange it as required.
Point to the reaction. The reaction required to simulate Gibbs Reactor is already present.

This is because the reaction was already defined while simulating the Equilibrium Reactor.

So we need not define any new reaction.

Click Gibbs Reactor We are now ready to specify the Gibbs Reactor.

So let’s click on it.

Point to displaying properties. On the left, we can see a tab displaying properties related to the Gibbs Reactor.
Go to Connections

Click on drop down arrow against Inlet Stream

Select Feed.

Under Connections, click on the drop-down against Inlet Stream and select Feed.
Click on drop down arrow against Outlet Stream 1

Select Vapour Product.

Next, click on the drop-down against Outlet Stream 1 and select Vapour Product.
Click on drop down arrow against Outlet Stream 2

Select Liquid Product.

Then, click on the drop-down against Outlet Stream 2 and select Liquid Product.
Click on the drop down against Energy Stream

Select Energy.

After this, click on the drop-down against Energy Stream and select Energy.
Hover mouse at Calculation Parameters Now go to the next section, Calculation Parameters.
Parameters >> Reaction Set >> Default Set Under the tab Parameters, the first option is Reaction Set.

By default, it is Default Set.

Click drop down against Calculation Mode

Select Define Outlet Temperature

Next, click on the drop-down against Calculation Mode.

Select Define Outlet Temperature.

Click drop down against Minimization Method

Select Calculate Reaction Extents

Next, click on the drop-down against Minimization Method.

Select Calculate Reaction Extents.

Point to Calculate Reaction Extents. This procedure is similar to Equilibrium Reactor.
Outlet Temperature >> 225 degree C Enter 225 degree C against Outlet Temperature.
Calculation Parameters >> Compounds Next, click on Compounds tab.
Point to Compounds This is to indicate the compounds that will react in the reaction.

Under Compounds, check all the boxes against all the compounds.

Now we will run the simulation.
Click Solve Flowsheet So, from the toolbar, click on Solve Flowsheet button.
Click Gibbs Reactor When the calculations are completed, click on the Gibbs Reactor in the flowsheet.
Point to Property Editor Window

Hover mouse at Results

Go to the Property Editor Window of the Gibbs Reactor.

Locate the Results section.

Results >> Reactions Under the Reactions tab, check Extent.

It is 20.043.

This is the extent of the water gas shift reaction at 225 degree C.

For the Equilibrium Reactor, it was 20.043 as well.

Results >> Conversions Now, go to Conversions tab.

We will look into the individual conversion of all the reactants.

Here for Carbon monoxide, the conversion is 92.2478% and for Water, it is 92.2478%.

For the Equilibrium Reactor, the conversions for both the compounds were 92.2478% as well.

Let us now redo the simulation with the other available Minimization Method.

This Minimization Method is called Direct Gibbs Energy Minimization.


Let us go back to the slides.
Slide Number 7

Direct Gibbs Energy Minimization method

In this method, Equilibrium composition for the final Gibbs energy is at minimum.

This method does not use any reaction to calculate the Gibbs energy.

Rather it uses an Element Matrix that we are going to define later.

Let us verify this.
Go to Calculations Parameters >> Parameters >> Reaction Set

Point to Reaction Set option

The default reaction which is already set, has a reaction in it.

So, let’s create a reaction set with no reaction.

Tools >> Reactions Manager

Point to Chemical Reactions Manager

Under Tools, click on Reactions Manager.

Chemical Reactions Manager window opens.

Reaction Sets >> Add New Reaction Set Under Reaction Sets tab, click on the green coloured Add New Reaction Set button.
Point to DWSIM – Reaction Set Editor DWSIM – Reaction Set Editor window opens.
Identification >> Name >> No Reaction Under Identification, enter the Name as No Reaction.
At the bottom, Click on OK button

Close Chemical Reactions Manager window.

At the bottom, click on OK button.

And then close the Chemical Reactions Manager window.

Press Solve Flowsheet button. Now press Solve Flowsheet button.
Point to Reaction set. A reaction set with no reaction is created.
Note that, this step of creating a reaction set with no reaction is not required.

I am doing this to demonstrate that Direct Gibbs Energy Minimization method works without any reaction.

Click Gibbs Reactor Once again click on the Gibbs Reactor.
Point to Calculation Parameters Go to Calculation Parameters section.
Click drop down against Reaction Set

Select No Reaction.

Then click on the drop-down against Reaction Set and select No Reaction.
Point to Calculation Mode There will be no change in Calculation Mode.

It will remain the same as Define Outlet Temperature.

Click drop down against Minimization Method

Select Direct Gibbs Energy Minimization.

Next, click on the drop-down against Minimization Mode.

Select Direct Gibbs Energy Minimization.

Point to Outlet Temperature Again, there will be no change in Outlet Temperature.

It will remain as 225 degree C.

Calculation Parameters >> Compounds After this, go to Compounds tab.

Note that, all the checkboxes are already selected.

Calculation Parameters >> Elements Now go to Elements tab.

In this tab, we will enter the required elements for the reaction.

They are Hydrogen. Oxygen and Carbon.

We will also specify the number of elements present in the selected compounds.

Configuration >> Add Element Under Configuration, click on Add Element three times.
Matrix >> Element >> H Under Matrix, we can see that three blank rows has been inserted.

For the first blank row, enter H for Hydrogen.

Matrix >> Element >> O For the next blank row, enter O for Oxygen.
Matrix >> Element >> C For the last blank row, enter C for Carbon.
Point to the elements All the elements have been added.

Now, we will enter the number of elements for all the selected compounds.

Carbon monoxide >> H: 0, O: 1, C: 1. Under Carbon monoxide column, enter:

0 for H

1 for O

and 1 for C

Then press Enter.

Water >> H: 2, O: 1, C: 0. Similarly, under Water column, enter:

2 for H

1 for O

and 0 for C

Then press Enter.

Hydrogen >> H: 2, O: 0, C: 0. Next, under Hydrogen column, enter:

2 for H

0 for O

and 0 for C

Then press Enter.

Carbon dioxide >> H: 0, O: 2, C: 1. Similarly, under Carbon dioxide column, enter:

0 for H

2 for O

and 1 for C

Then press Enter.

Click on Save Changes button. Click on Save Changes button.
The element matrix is now complete.
Now we will run the simulation.
Click Solve Flowsheet So, from the toolbar, click on Solve Flowsheet button.
Click Gibbs Reactor When the calculations are completed, click on the Gibbs Reactor in the flowsheet.
Point to Property Editor Window

Hover mouse at Results

Go to the Property Editor Window of the Gibbs Reactor.

Locate the Results section.

Results >> Conversions Under Conversions tab, check the individual compounds conversion.

Here for Carbon monoxide, the conversion is 92.2478% and for Water, it is 92.2478%.

Equilibrium Reactor

other Minimization Methods in Gibbs Reactor.

In all the above explained methods, conversions for both the compounds was found to be 92.2478%
Let's summarize.
Slide Number 6


Summary

In this tutorial, we have learnt to
  • Simulate a Gibbs Reactor
  • Use different Minimization Methods
  • Calculate Conversion percentage and Reaction extent
  • Compare Equilibrium and Gibbs Reactor values
Slide Number 7


Assignment


Compounds:


Nitrogen (N2)

Hydrogen (H2)

Ammonia (NH3)


Property Package: Peng-Robinson


Inlet stream:


Mass Flow: 1000kg/h

Mole Fraction(N2): 0.5

Mole Fraction(H2): 0.5

Mole Fraction(NH3): 0


Temperature: 425 degree C

Pressure: 200 bar

Reaction: N2 +3 H2 = 2 NH3

As an assignment,



Repeat this simulation with different compounds and thermodynamics.




Different feed conditions



Different Minimization Methods

Slide Number 8About the Spoken Tutorial Project Watch the video available at the following link.

http://spoken-tutorial.org/

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Slide Number 9

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Slide Number 10


Forum Slide

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Explain your question briefly.

Someone from the FOSSEE team will answer them.

Please post your times queries in this forum.
Slide Number 11

DWSIM Flowsheeting Project

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Slide Number 14

Acknowledgements

Spoken Tutorial and FOSSEE projects are funded by NMEICT, MHRD, Government of India.
Slide Number 15

Thanks

This tutorial is contributed by Kaushik Datta and Priyam Nayak.

Thanks for joining.

Contributors and Content Editors

Kaushik Datta, Nancyvarkey