DWSIM-3.4/C2/Shortcut-Distillation/English
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Welcome to the spoken tutorial on Simulating a Shortcut distillation column in DWSIM.
I am Kannan Moudgalya |
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In this tutorial, we will simulate a Shortcut distillation column.
We will learn to calculate Minimum number of stages Minimum reflux ratio Feed stage location Condenser and reboiler duty To achieve a particular product specification |
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To record this tutorial, I am using DWSIM 3.4 |
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To practice this tutorial you should know
How to add components to a flowsheet How to select thermodynamic packages How to add material streams and specify their properties The prerequisite tutorials are mentioned on our website, spoken hyphen tutorial dot org. |
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In the next two slides, we give specifications for the distillation problem.
This problem statement is given by Prof. Bill Luyben of Lehigh University. |
I have already opened DWSIM. | |
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Click on System of Units menu.
Select Custom 1. This allows us to customise units, which we will do next. |
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Let us click on Configure Simulation button.
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Add Benzene from the ChemSep Database
Next Toluene |
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We will next click Thermodynamics and then Property Packages.
Scroll down and select Raoult’s Law. |
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Below the Thermodynamics option, you see Options menu.
Click this. |
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Click Units System.
Let me bring this inside. |
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Pressure menu appears at the top of this list.
Click and choose atm for atmosphere. |
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Below the Pressure menu is the Molar flow rate menu.
Click it and select kmol/h. |
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Click on Back to simulation. |
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Let us insert a feed stream that has to be distilled.
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Enter 0.4 for benzene and 0.6 for toluene. |
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Apply and Close. |
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We will change the name of this stream to Feed. |
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Click on Properties.
Scroll to the top. |
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Click on Specification.
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Choose Pressure and Vapor Fraction.
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Locate the Molar flow rate option.
It has the units of kmol/h. |
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Click on this field.
Enter 100. |
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Locate Molar Fraction (Vapor Phase).
The default value is 0. This indicates saturated liquid. Let us leave it as it is. |
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Let us insert a Shortcut column to the flowsheet.
Locate it from the Object palette. The Shortcut Column is based on Fenske-Underwood-Gilliland method. Click on it and drag it to the flowsheet. Let us arrange it. |
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Now let us insert two output streams.
One will be distillate and the other is Bottoms. To do that let us drag two material streams. As they are output streams. We will leave them unspecified. |
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We will change the name of these streams to Distillate and Bottoms. |
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Let us now insert two Energy streams.
For Condenser duty and Reboiler duty. |
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Name these streams as C-Duty and R-Duty. |
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We are now ready to specify the Shortcut distillation column.
Click on it and select it. |
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Go to the Selected Object window.
Under Properties tab, locate Connections menu.
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The first option is Feed.
Let me click on Feed menu. A down arrow appears, indicating a menu. Click this arrow. Here we choose Feed. |
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Now click on the next option which says Distillate.
Click on the drop down arrow and select Distillate. |
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Similarly for bottoms choose Bottoms |
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The next option is Condenser Duty.
Let me click on it and select C-Duty. |
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Similarly choose R-Duty for Reboiler.
This completes the connectivity of the flowsheet. |
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Under Properties tab, locate Parameters section.
This section is used to specify various attributes of a Shortcut Column. In this section, the first option is Condenser. By default, it is total condenser. If a partial condenser is required, you can change it here. Here we leave it as it is. |
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Let us enter the reflux ratio.
Click on it. |
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Here we enter the value 2 in the field next to it. |
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We will specify the Product composition.
Let us first specify light key details in bottoms. To do this, let me click light key. Click the arrow and choose Benzene. |
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In the given field on the next row, enter 0.05. |
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Similarly for the heavy key, choose Toluene.
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Now we specify the heavy key in Distillate.
We enter 0.05. |
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Next in the list is the Condenser Pressure.
The default value is 0 atmosphere. |
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We will change it to 1 atmosphere. |
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Similarly we will change reboiler pressure to 1 atmosphere |
Now we will run the simulation. | |
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To do this, go to the calculator options.
Click on the Play button. |
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Now click on the Recalculate button. |
click Shortcut column | When the calculations are completed, click on the Shortcut column. |
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Under Properties tab, locate Results menu.
This shows all the required results like Minimum Reflux Ratio Minimum Number of Stages Actual Number of Stages Optimal Feed Stage, etc. |
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I have tabulated these results in a slide. |
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Let me save this simulation.
I have saved this as shortcut end. |
Let me summarise. | |
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We learnt how to specify a shortcut distillation column.
To specify key components, purities, and minimum reflux ratio. To use custom units. To calculate minimum reflux ratio optimal feed location and total number of trays |
Let me give some assignments. | |
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The assignment in this slide has to do with mass balances.
I use blue colour to indicate streams and equipment. |
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Let us go to the next Assignment.
Carry out energy balance as mentioned. |
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Repeat the simulation with different product purities.
Determine how the energy requirement changes. |
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Repeat this simulation with different thermodynamics.
Repeat this simulation with different feed conditions. Try to reason your results. |
We have come to the end of this tutorial | |
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Thanks for joining. Good bye. |