Difference between revisions of "DWSIM/C2/Plug-Flow-Reactor/English"

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Revision as of 12:45, 17 April 2017

Visual Cue Narration
Slide Number 1

Title Slide

Welcome to this spoken tutorial on Simulating a Plug Flow Reactor(PFR) in DWSIM.
Slide Number 2

Learning Objective

In this tutorial, we will learn to:
  • Define a kinetic reaction
  • Simulate a Plug Flow Reactor (PFR)
  • Calculate Conversion and Residence time for a reaction in a PFR.
Slide Number 3

System Requirements

To record this tutorial, I am using


  • DWSIM 4.3 and
  • Windows 7

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
  • how to select thermodynamic packages
  • how to add material and energy streams and specify their properties.
Slide:

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 5


Reaction, Package and Inlet Condition


Reaction:

N2 + 3 H2 ⇌ 2 NH3

Inlet Stream:


Mass Flow: 3600 kg/h

Mole Fraction(N2): 0.5

Mole Fraction(H2): 0.5

Temperature: 425 degree C

Pressure: 200 bar


Property Package: Peng Robinson(PR)

We will develop a flowsheet to determine the exit composition from an Isothermal PFR.


Here we give reaction, inlet stream conditions and property package.

Slide Number 6


Reactor Parameters and Reaction Kinetics


PFR Dimensions:

Volume: 1 m3, length: 1.5 m


Reaction rate:

r A = KCan

K = 0.004, n = 1

Next, we give PFR dimensions and reaction kinetics.
File >> New Steady-state Simulation


Point to Simulation Configuration Wizard window


Click on Next.

I have already opened DWSIM on my machine.


Go to File menu and select New Steady-state Simulation.


Simulation Configuration Wizard window appears.


At the bottom, click on Next.

Type Nitrogen in the Search tab


ChemSep database >> Nitrogen


Click Add


Type Hydrogen in the Search tab


Type Ammonia in the Search tab


Click on Next.

First, we will add the compounds.


In the Compounds Search tab, type Nitrogen.


Select Nitrogen from ChemSep database.


Similarly, add Hydrogen from ChemSep database.


Next, add Ammonia from ChemSep database.


Now, all the compounds are added.


Click on Next.

Point to Property Packages


Property Packages >> Available Property Package


Double click on Peng-Robinson (PR)


Click on Next.

Now comes Property Packages.


From Available Property Package list, double-click on Peng-Robinson (PR).


Then click on Next.

Point to Flash Algorithm


Default Flash Algorithm >> Nested Loops (VLE)


Click Next

We are moved to Flash Algorithm.


From Default Flash Algorithm select Nested Loops(VLE)


Click on Next.

Point to System of Units


System of Units >> C5


Click on Finish

Next option is System of Units.


So we select C5.


This has the desired system of units according to our problem statement.


Then click on Finish.

Let us maximize the simulation window.
Point to Object Palette


Go to Streams Section

Click and drag Material Stream to the flowsheet

Now let’s insert a feed stream that enters the PFR.


On the right hand side of main simulation window, go to Object Palette.


From Streams section, drag and drop a Material Stream to the Flowsheet.

Click on MSTR-000 Click on Material Stream “MSTR-000” to view its properties.
Type Feed Let’s change the name of this stream to Feed.
Input Data>> Flash Spec>> Temperature and Pressure(TP) Now we will specify the Feed stream properties.


Under 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.


So let’s not change it.

Input Data >> Temperature >> 425 C

Press Enter

Change Temperature to 425 degC and press Enter to accept the new value.
Input Data >> Pressure >> 200 bar

Press Enter

Change Pressure to 200 bar and press Enter.
Input Data >> Mass Flow >> 3600 kg/h

Press Enter

Change Mass Flow to 3600 kg/h 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.


So, let’s not change it.

Nitrogen: 0.5


Hydrogen: 0.5


Ammonia: 0

Now for Nitrogen, enter the Amount as 0.5 and press Enter.


Similarly, for Hydrogen, enter it as 0.5 and press Enter.


For Ammonia, enter 0 and press Enter.

Click Accept Changes On the right, click on this green tick to Accept Changes.
Now we will define the Kinetic Reaction.
Tools >> Reactions Manager


Point to Chemical Reactions Manager

Under Tools, click on Reactions Manager.


Chemical Reactions Manager window opens.

Chemical Reactions >> Add Reaction Under Chemical Reactions tab, click on the green coloured Add Reaction button.
Click on Kinetic Then click on Kinetic.
Point to Add New Kinetic Reactions Add New Kinetic Reactions window opens.
Identification >> Name >> Ammonia Synthesis First part is Identification.


Under Identification, enter the Name as Ammonia Synthesis.

Description >> Irreversible reaction for synthesis of Ammonia from Nitrogen and Hydrogen Next, enter the Description.


“Irreversible reaction for synthesis of Ammonia from Nitrogen and Hydrogen”

Point to Components, Stoichiometry and Reaction Orders Next part is a table of Components, Stoichiometry and Reaction Orders.
Point to Name field First column Name, shows the available components here.
Point to Molar Weight Second column corresponds to its Molar Weight.
Point to Include Next column is Include.


It indicates the components which will take part in the reaction.


Under Include, check all the check boxes against all the components’ names.

Point to BC


Check Nitrogen check box

Fourth column is BC.


It indicates the base component of the reaction.


Under BC, check the Nitrogen check box as Nitrogen is the base component.

Point to Stoich. Coeff


Stoich. Coeff >> Nitrogen: -1, Hydrogen: -3, Ammonia: 2

Next column is Stoich. Coeff. (stoichiometric coefficients)


Under Stoic Coeff column, enter:


-1 for Nitrogen,

-3 for Hydrogen,

and 2 for Ammonia.

Then press Enter.


Negative sign is to indicate the components as Reactants.

Point to Stoichiometry field In the Stoichiometry field, we can see it is showing OK.


So the reaction is balanced after entering the stoichiometric coefficients.

Point to Equation field Here the Equation field shows the reaction equation.
Point to DO


DO >> Nitrogen: 1

Next column is DO, which indicates direct/forward reaction order.


We are considering the reaction to be First order with respect to Nitrogen.


So we will enter 1 in the DO column against Nitrogen.


And then press Enter.

Point to RO Next column is RO which indicates reverse reaction order.


Since we are considering an irreversible reaction, we will not enter anything here.

Point to Kinetic Reactions Parameters Then comes Kinetic Reactions Parameters.
Basis >> Molar Concentrations Our rate is in terms of molar concentration.


So, we will select Basis as Molar Concentrations.

Fase >> Vapor Select Fase as Vapor.
Point to Tmin and Tmax


Next is Tmin and Tmax.


It gives temperature range within which rate expression is assumed to be valid.

Tmin (K) >> 700


Tmax (K) >> 2000

So, enter Tmin (K) as 500 and Tmax (K) as 2000.
Point to Direct and Reverse Reactions Velocity Constant


Direct Reaction: A >> 0.004

Now go to Direct and Reverse Reactions Velocity Constant.


In Direct Reaction, enter A as 0.004

Click OK


Close Chemical Reactions Manager window.

Click OK and close the Chemical Reactions Manager window.
Go to Object Palette>>Unit Operations


Click and drag Plug-Flow Reactor (PFR) to the flowsheet


Now let us insert a Plug-Flow Reactor (PFR) into the flowsheet.


Go to Object Palette.


Under Unit Operations, click on Plug-Flow Reactor (PFR)


Click on it and drag it to the flowsheet.


Let us now arrange it as required.

Click and drag Material Stream to the flowsheet We will insert one Output Stream.


To do so, drag one Material Stream.


Let us once again arrange it.


As this is an output stream, we will leave it unspecified.

Type Product We will change the name of this stream to Product.
Click and drag Energy Stream to the flowsheet Next, we will insert one Energy Stream.
Type Energy. And name this stream as Energy.
Click Plug-Flow Reactor (PFR) We are now ready to specify the Plug-Flow Reactor.


Click on it.


On the left, we can see a tab displaying properties related to the PFR.


This tab is called Property Editor Window.

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


Select Product.

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


Select Energy.

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


By default, it is Default Set.


Since we have only one reaction, we leave it as it is.

Click drop down against Calculation Mode


Select Isothermic

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


Select Isothermic.

Reactor Volume >> 1 m3


Press Enter

Then click on the field against Reactor Volume and enter 1 m3.


Then press Enter.

Reactor Length >> 1.5 m


Press Enter

Click on the field against Reactor length and enter it as 1.5 m.


Then press Enter.

Now we will run the simulation.
Click Solve Flowsheet So, from the toolbar click on Solve Flowsheet button.
Click Plug-Flow Reactor When the calculations are completed, click on PFR in the Flowsheet.
Hover mouse at Results From the Property Editor Window of PFR locate Results section.
Results >> General Under General tab, check Residence time.


It is 0.013 h.

Results >> Conversions Under Conversions tab, check conversion for both the reacting compounds.


For Nitrogen, the conversion is 17.91% and for Hydrogen, it is 53.73%.

Insert >> Master Property Table Now we will check the material balances.


Go to Insert menu and select Master Property Table.

Double click on Master Property Table


Point to Configure Master Property Table

Double click on the Master Property Table to edit it.


Configure Master Property Table window opens.

Type Results - Plug Flow Reactor Enter Name as Results - Plug Flow Reactor
Type Material Stream Enter Object Type as Material Stream.

By default, Material Stream is already selected.


So we will not change it.

Object >> Feed and Product Under Properties to display, select Object as Feed and Product.
Configure Master Property Table>> Property Under Property, scroll down to see all the parameters.


Now select the properties as:


Temperature

Pressure

Mass Flow

Molar Flow

Vapor Phase Volumetric Fraction

Mass Flow (Mixture) / Nitrogen

Molar Flow (Mixture) / Nitrogen

Mass Flow (Mixture) / Hydrogen

Molar Flow (Mixture) / Hydrogen

Mass Flow (Mixture) / Ammonia

Molar Flow (Mixture) / Ammonia

Close this window.


Move the Master Property Table for better visibility.


Here we can see the corresponding results for Product and Feed.

Let us summarize.
Slide Number 7

Summary

In this tutorial, we have learnt to


  • Define a kinetic reaction
  • Simulate a Plug-Flow Reactor (PFR)
  • Calculate Conversion and Residence time for a reaction in a PFR
Slide Number 8


Assignment


Compounds:

Ethylene oxide, Water & Ethylene glycol


Property Package: Raoult's Law


Inlet stream:


Mass Flow: 1000kg/h

Mole Fraction(C2H4O): 0.2

Mole Fraction(H2O): 0.8

Temperature: 55 degree C

Pressure: 1 bar


PFR Dimensions:

Volume: 1 m3, Length: 1.2 m


Reaction rate:

r A = KCan, K = 0.005 1/s, n = 1

As an assignment,


Repeat this simulation with different compounds and thermodynamics.


Different feed conditions


Different PFR dimensions and reaction kinetics

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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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

TextBook Companion Project

The FOSSEE team coordinates coding of solved examples of popular books.


We give honorarium and certificates for those who do this.


For more details, please visit this site.

Slide Number 13

Lab Migration Project

The FOSSEE team helps migrate commercial simulator labs to DWSIM.


We give honorarium and certificates for those who do this.


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Slide Number 14

DWSIM Flowsheeting Project

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

We give honorarium and certificates for those who do this.

For more details, please visit this site.

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

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