DWSIM/C2/Sensitivity-Analysis-and-Adjust/English-timed
Time | Narration |
00:01 | Welcome to this tutorial on Sensitivity Analysis and Adjust in DWSIM. |
00:08 | In this tutorial, we will learn to: |
00:11 | Determine the exact Reflux Ratio for a separation |
00:15 | Perform Sensitivity Analysis and Adjust operation |
00:19 | This tutorial is recorded using,
DWSIM 5. 8 (Classic UI) Update 3and Windows 10 OS |
00:30 | But, this process is identical in Linux, Mac OS X or FOSSEE OS on ARM. |
00:38 | To practise this tutorial you should know to -
Open a simulation file in DWSIM |
00:45 | Carry out rigorous distillation simulation |
00:48 | Add components to a flowsheet |
00:51 | The prerequisite tutorials are available on this website. |
00:55 | You can access these tutorials and all the associated files from this site. |
01:01 | rigorous.dwxmz file used in the tutorial is provided as a Code file on this tutorial page. |
01:09 | Download the file from the Code Files link. |
01:13 | This slide shows the problem solved using Rigorous Distillation. |
01:18 | The purity achieved was less than what was desired. |
01:23 | To improve the purity, we need to increase the reflux ratio. |
01:28 | I have already opened DWSIM on my machine. |
01:32 | Open the file rigorous dot dwxmz. |
01:38 | Click on Distillate in the flowsheet. |
01:41 | Go to Property Editor Window. |
01:44 | Under Input Data, click on Compound Amounts tab. |
01:48 | Here the Benzene mole fraction is 0.988. |
01:53 | We would like to increase this to 0.99. |
01:57 | Let us attempt this by increasing the reflux ratio. |
02:01 | To do so, click on Optimization option on the menu bar. |
02:07 | Now click on Sensitivity Analysis option.
Sensitivity Analysis tab opens. |
02:14 | Here we can see five menus in the menu bar of Sensitivity Analysis. |
02:20 | Now click on Sensitivity Studies, if not already selected.
On my system, by default, it is already selected. |
02:30 | Under Case Manager, we can see four buttons. |
02:34 | Click on New button. |
02:36 | This will help in creating a new Sensitivity Analysis case. |
02:41 | We see the name SACase0. |
02:45 | Here we want to increase the reflux ratio so as to get better purity. |
02:50 | Thus, reflux ratio is the independent variable. |
02:54 | Let us do this through the Independent Variables. |
02:58 | Under Sensitivity Analysis, click on Independent Variables tab. |
03:04 | Under Independent Variable 1, click on the drop-down against Object. |
03:10 | Select DC-005, the name of our distillation column. |
03:16 | On the right hand side, click on the drop-down against Property. |
03:22 | Now scroll down and select Condenser Specification Value. |
03:28 | It plays the role of the reflux ratio. |
03:31 | Recall that we want our reflux ratio to be greater than 2.317. |
03:38 | So, we will enter the Lower limit as 2.317 |
03:43 | Change the Upper limit to 2.5 |
03:47 | Change the Number of Points to 6 |
03:51 | Now under Sensitivity Analysis, click on Dependent Variables tab. |
03:57 | On the left hand side, we can see a column named Variables. |
04:03 | Below that, locate a green coloured plus button to Add new variables. |
04:09 | Click on it. A new row appears. |
04:12 | Click on the drop-down against Object.
Select Distillate. |
04:20 | Now click on the drop-down against Property. |
04:25 | Scroll down and select Molar Fraction (Mixture) – Benzene. |
04:32 | Next click on the Results tab to the right of the Dependent Variables tab. |
04:38 | Then click on Start Sensitivity Analysis button. |
04:42 | We see the column getting simulated for reflux ratios, one by one. |
04:47 | At the end of the simulation, we get the message Done. |
04:52 | Here we can see results for six reflux ratios, from 2.317 to 2.5 |
05:00 | We also see the corresponding benzene compositions. |
05:05 | Now under Sensitivity Analysis, click on Independent Variables tab.
Change the Number of Points to 11. |
05:15 | Again click on Results tab. |
05:18 | Click on Start Sensitivity Analysis button once again. |
05:22 | You can see that simulation runs to show eleven results this time. |
05:28 | We can see that the desired purity of 0.99 will be achieved between 2.3719 and 2.3902 |
05:37 | Choose these as the lower and upper limits in Independent Variables. |
05:43 | Again click on Results tab. |
05:46 | Click on Start Sensitivity Analysis button once again. |
05:51 | Here we get the reflux ratio value as 2.382. |
05:56 | This way we can determine the exact reflux ratio required for 0.99 purity. |
06:03 | We can also see these results in a graphical form.
Now under Sensitivity Analysis, click on Chart tab. |
06:13 | On the left of the window, click on the Draw button. |
06:17 | On the right, we can see the chart here. |
06:21 | This graph plots between Distillate composition vs condenser specification value.
That is, the reflux ratio. |
06:30 | Let me save this simulation as sensitivity. |
06:37 | Now close the Sensitivity Analysis tab.. |
06:42 | We have learnt to calculate the desired reflux ratio by trial and error method. |
06;46 | DWSIM has a powerful method to directly calculate the reflux ratio.
It is called Adjust. |
06:55 | Now at the bottom of the main simulation window, click on Logical Ops tab. |
07:01 | Click on Controller Block.
Drag and drop it outside the column, below the distillate. Now, click on it. |
07:11 | On the left, we can see a tab displaying properties related to Adjust. |
07:17 | Under Linked Objects, click on the drop-down against Manipulated Object.
Now select DC-005. |
07:28 | Next, click on the drop-down against Manipulated Property. |
07:34 | Then select Condenser Specification Value. |
07:38 | Next, click on the drop-down against Controlled Object and select Distillate. |
07:46 | Next, click on the drop-down against Controlled Property.
And select Molar Fraction(Mixture) / Benzene. |
07:57 | Now, go to Parameters. |
08:00 | Enter Set-Point/Offset (Controlled Property) as 0.9901 and press Enter. |
08:09 | I shall enter a slightly larger number 0.9901. |
08:14 | I want you to think about why I have entered a slightly larger number. |
08:19 | Now, select the check-box against Solve Globally. |
08:24 | Then we will run the simulation. |
08:27 | So, from the toolbar, click on Solve Flowsheet button. |
08:31 | Let us check the distillate purity.
Click on Distillate in the flowsheet. |
08:37 | From the Property Editor window, go to Input Data tab. |
08:41 | Under Compound Amounts tab, we can see that the benzene composition is 0.99. |
08:49 | Let us now check what reflux ratio is required for this.
To do this, click on the Distillation column. |
08:58 | Under Column Specs, click on Condenser tab. |
09:02 | Under Compound, we see a value of 2.382 |
09:07 | It is the same as what we obtained in the Sensitivity Analysis. |
09:13 | Let me save this simulation as adjust. |
09:20 | Let's summarize. |
09:22 | In this tutorial, we have learnt to:
Determine the exact Reflux Ratio for a separation |
09:29 | Performed Sensitivity Analysis and Adjust operation |
09:33 | I have some assignments for you. |
09:36 | Simulate this problem statement using a Distillation column. |
09:40 | Here we give different Compounds, feed conditions and Thermodynamics. |
09:46 | Different Column Configuration |
09:49 | Let us go to the next assignment. |
09:52 | Perform sensitivity analysis on the simulated distillation column. |
09:57 | To find the reflux ratio such that mole fraction of water in bottoms is 0.99 |
10:05 | Using Adjust/Controller Block, verify the results obtained using the analysis. |
10:12 | Watch the video available at the following link.
It summarizes the Spoken Tutorial project. |
10:19 | The Spoken Tutorial Project Team conducts workshops and gives certificates.
For more details, please write to us. |
10:29 | Please post your timed queries in this forum. |
10:33 | The FOSSEE team coordinates conversion of existing flowsheets into DWSIM. |
10:39 | We give honorarium and certificates for those who do this.
For more details, please visit this site. |
10:48 | The FOSSEE team helps migrate commercial simulator labs to DWSIM. |
10:55 | We give honorarium and certificates for those who do this.
For more details, please visit this site |
11:04 | Spoken Tutorial and FOSSEE projects are funded by NMEICT, MHRD, Government of India. |
11:13 | We thank the DWSIM team for making it as an open source software. |
11:20 | This tutorial was originally recorded by Prof Kannan Moudgalya in September 2015.
This is Kaushik Datta from IIT Bombay. Thanks for joining. |