View source for DWSIM/C3/Custom-Unit-Operation-using-Python/English-timed

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|| '''Time'''
|| '''Narration'''
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|| 00:01
|| Welcome to this tutorial on simulating a '''Custom Unit Operation '''using '''Python.'''
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|| 00:07
|| In this tutorial, we will learn to:

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|| 00:10
||  Create a custom unit operation using '''Python'''

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|| 00:14
||  Calculate '''Overall mass '''and '''mole flow rate'''

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|| 00:18
||  Calculate '''Enthalpy''' and '''outlet pressure'''
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|| 00:22
|| To record this tutorial, I am using

'''DWSIM 5. 6 update 8''' '''(Classic UI) '''and  '''Windows 10'''

|- 
||00:32
|| But, this process is identical in '''Linux, Mac OS X '''or '''FOSSEE OS on ARM'''.
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||00:40
|| To practice this tutorial, you should know to-

Add components to a '''flowsheet'''

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||00:46
||  Select '''thermodynamic''' packages

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||00:49
||  Add '''material''' streams and specify their properties

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|| 00:54
|| The prerequisite tutorials are available on our website.

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||00:58
|| You can access these tutorials and all the associated files from this site.
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||01:04
|| We will develop a '''flowsheet''' to determine the '''product stream temperature, pressure ''', '''Molar flowrate, compositions '''and '''molar enthalpy '''from a '''mixer model''' created using '''Python.'''
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|| 01:16
|| Here we give '''Inlet Stream Conditions''' and '''Pressure''' calculation parameter of the '''product stream.'''

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||01:22
|| '''DWSIM-Python''' file used in the tutorial is provided as a code file on our site.

Download the files from '''Code Files''' link.
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||01:33
|| I have already opened '''DWSIM''' on my machine.
|- 
|| 01:37
|| Please ensure that '''DWSIM''' opens as an '''administrator'''.

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||01:42
||  Please note:

If '''DWSIM''' is not opened with '''administrator privileges''', the '''Python unit operation''' will not work.

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||01:50
|| Go to '''File''' menu and click on '''Open File'''.

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|| 01:56
||I have already downloaded and extracted the file on my '''Desktop'''.

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||02:01
|| Select the file from the '''Desktop'''.

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||02:04
|| This file already contains all the material streams necessary for this tutorial.

|- 
|| 02:10
|| Let us maximize the simulation window.
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|| 02:13
|| Now at the bottom of the main simulation window, go to '''User Models '''tab.
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|| 02:19
|| Here we will add the '''Python script''' in the '''flowsheet'''.
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|| 02:23
|| Drag and drop '''Python Script''' to the '''flowsheet''' area.
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|| 02:27
|| Let us change the name of this '''Unit Operation '''to '''Custom Mixer'''.
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|| 02:32
|| Now, we will connect '''material streams''' to '''inlet''' and '''outlet ports''' of the '''Custom Mixer'''.
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|| 02:39
|| For this click on '''Custom Mixer.'''
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|| 02:42
|| Under '''Connections,''' click on the drop-down against '''Inlet Stream 1.'''

And select '''Methanol.'''
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|| 02:51
|| Next, click on the drop-down against '''Inlet Stream 2''' and select '''Water.'''
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|| 02:58
|| Then, click on the drop-down against '''Outlet Stream 1''' and select '''Mixed Product.'''
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|| 03:06
|| All the connections are now complete. 

Now we will write the code to perform the computation.
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|| 03:12
|| On the left of the window, click on '''Open Python Script Editor '''button.
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|| 03:18
|| '''Custom Mixer - Script Editor''' tab opens.
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|| 03:22
|| Here we will type the '''Python script''' to perform the '''mixer''' operations.
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|| 03:27
|| First, we will import the '''thermodynamics package''' and its related functions to the '''script'''.
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|| 03:34
|| Type this code in the '''script'''.

This is to import the '''Thermodynamics Packages''' and related '''functions''' to '''Python'''.
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|| 03:43
|| Now we will extract the '''input''' from the '''feed streams.''' 
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|| 03:48
|| Type this code in the '''script'''.

'''ims1 '''and '''ims2''' are the reference to '''material streams''' that are connected in '''Inlet Stream 1''' and '''Inlet Stream 2.'''

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||04:00
|| They get recorded as '''feed1''' and '''feed2.'''
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||04:05
|| Type this code in the '''script'''.

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||04:08
|| This is to read the '''pressure''' from '''inlet material streams.'''

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||04:12
|| Here, the variables '''P underscore 1''' and '''P underscore 2''' store the '''pressures''' of '''Methanol''' and '''Water streams'''.
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|| 04:21
|| '''GetProp''' is a '''function''' which is used to extract information from the '''inlet material stream.'''
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|| 04:28
|| '''GetProp function''' has 5 '''arguments'''.

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||04:32
|| These '''arguments''' have to be specified according to the information that needs to be '''extracted'''.
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|| 04:39
|| First '''argument''' is the '''property name'''. 

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||04:42
|| This is to specify the '''property''' which has to be stored in the '''variable'''.

Here '''pressure''' is specified.
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|| 04:50
|| Second '''argument''' is the '''phase'''.

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||04:53
|| This is to indicate the '''phase''' for which the '''property''' specified in the first '''argument''' has to be stored.

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||05:00
|| Here '''Overall''' is specified.
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|| 05:03
|| Third '''argument''' is the '''component ID'''.

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||05:07
|| Since we are storing the '''pressure''' of overall '''stream''' and not individual components, '''None''' is specified.
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|| 05:15
|| The fourth '''argument''' is the '''calculation type'''. 

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||05:19
|| Here we have to enter '''Pure '''or '''Mixture.'''

Since the '''property''' calculation '''type''' doesn’t apply to '''pressure''', we will leave blank here.
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|| 05:30
|| The fifth '''argument''' is the '''basis'''. 

|- 
||05:34
|| '''Mole''' or '''mass''' has to be entered here to specify the '''property''' basis.

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||05:40
|| Since the '''property''' basis doesn’t apply to '''pressure''', we will leave it blank here.
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|| 05:46
|| Type this code in the '''script'''.

This is to read the overall '''mass flow rates''' from the '''inlet material streams'''.

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||05:54
|| variables '''massflow underscore 1''' and '''massflow underscore 2''' store total '''mass flow rates''' of '''Methanol''' and '''Water''' streams.
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|| 06:04
|| Type this code in the '''script'''.

This code will read the '''mole fractions''' of the components from the '''inlet material streams'''.

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||06:13
|| Here, we see the variables '''molefrac_1''' and '''molefrac_2. '''

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||06:20
|| They''' '''store '''mole fractions''' of the components from the '''streams''' in form of '''1 Dimensional array.'''
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|| 06:27
|| Type this code in the '''script'''.

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||06:30
|| Here, variables '''moleflow underscore 1''' and '''moleflow underscore 2''' store total '''mole flow rates''' of the '''streams'''.
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|| 06:39
|| Type this code in the '''script'''.

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||06:42
|| This is to read the specific '''enthalpy''' from the '''inlet material streams.'''

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||06:47
|| Variables '''enthalpy underscore 1''' and '''enthalpy underscore 2''' store the specific '''enthalpies''' of the '''streams'''.
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|| 06:55
|| Please note that the fourth '''argument''' is specified as a '''Mixture'''.

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||07:00
|| Here we are storing the specific '''enthalpy''' of the '''overall stream'''.

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||07:05
|| So, calculation '''type''' is specified as '''Mixture.'''
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|| 07:10
|| Type this code in the '''script'''.

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||07:13
|| All the required '''properties''' for the '''outlet stream''' are initialized here. 

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||07:18
|| The '''variables''' are initialized as '''vectors'''.

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||07:22
|| This makes it easy to set the values in the '''outlet stream''' using the '''SetProp function.'''
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|| 07:29
|| Now we will code the calculation routine.
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|| 07:33
|| First we will calculate the overall '''mass flow rate''' of the '''outlet stream'''.
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|| 07:38
|| Type this code in the '''script'''.

Total '''mass flow rate''' of the '''outlet stream''' is calculated and stored in the variable '''massflow underscore 3.'''
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|| 07:49
|| Now we will calculate the overall '''mole flow rate''' of '''outlet stream'''.
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|| 07:55
|| Type this code in the '''script'''.

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||07:58
|| Total '''mole flow rate''' of '''outlet stream''' is calculated and stored in the variable '''moleflow underscore 3'''.
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|| 08:06
|| Next we will calculate the specific '''enthalpy''' of '''outlet stream'''.
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|| 08:11
|| Type this code in the '''script'''.

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||08:14
|| Total '''enthalpy''' of the '''outlet stream''' is calculated and stored in the variable '''totalenthalpy.'''

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||08:21
|| Similarly,''' '''specific '''enthalpy''' of the '''outlet stream''' is calculated and stored in the variable '''enthalpy underscore 3'''.
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|| 08:30
|| Next we will calculate the individual component '''mole flow rates''' in the '''outlet stream'''.
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|| 08:36
|| Type this code in the '''script'''.

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||08:39
|| Mole flow rates''' of component 1 and component 2 are calculated and stored in '''totalmolflow underscore comp1''' and '''totalmolflow underscore comp2'''.
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|| 08:50
|| Now we will calculate the '''mole fraction''' of components in the '''outlet stream'''.
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|| 08:56
|| Type this code in the '''script'''.

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||08:59
|| Component '''mole fractions''' are calculated and stored in the variable '''molfrac underscore 3'''.
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|| 09:06
|| Now we will calculate the '''outlet pressure.'''
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|| 09:10
|| Type this code in the '''script'''.

'''Outlet pressure''' is calculated and stored in the variable '''P underscore 3'''.
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|| 09:19
|| Now we will pass the calculated '''output variables''' to the '''Mixed Product material stream'''.
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|| 09:26
|| Type this code in the '''script'''.

'''oms1''' is the reference to the '''material stream''' connected to the '''Outlet Stream 1.'''
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||09:35
|| Type this code in the '''script'''.

This is to clear any calculated values stored during previous runs.
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||09:44
|| Now we will pass the calculated '''output variables''' to the '''Mixed Product material stream'''.
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|| 09:51
|| Type this code in the '''script'''.

This is to pass the calculated specific '''enthalpy''' to the '''Outlet Stream 1'''.
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|| 10:00
|| '''SetProp''' is a '''function''' used to assign values to the '''output stream'''. 

|- 
||10:06
|| It is a similar '''function''' to that of '''GetProp'''.

'''SetProp function''' has six '''arguments'''. 

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||10:14
|| First five '''arguments''' are same as that of '''GetProp function'''.
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||10:19
|| The sixth '''argument''' is the '''output variable'''. 

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||10:23
|| This is to specify the '''vector variable''' that we want to assign to that particular '''property'''.

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||10:29
|| We want to assign the '''vector enthalpy underscore 3''' to '''enthalpy''' of the '''Outlet Stream 1'''.
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|| 10:37
|| Similarly we will pass the remaining calculated '''variables''' to the '''Outlet Stream 1'''.
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|| 10:42
|| Type this code in the '''script'''.

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||10:45
|| This is to pass the calculated '''pressure, component mole fractions''' and '''total mass flowrate''' to the '''Outlet Stream 1'''.
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|| 10:53
|| Type this code in the '''script'''.

This is to set the flash calculation method for the '''Outlet Stream 1'''.
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|| 11:01
|| '''out.PropertyPackage.DW_CalcEquilibrium''' is a '''function''' used to set the method of '''flash''' calculation used. 

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||11:11
|| The default '''flash '''calculation method is done with the '''Temperature and Pressure (TP Flash)'''.

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||11:17
|| Here we do not know the '''outlet temperature'''.

So, we set the '''flash type''' to '''Pressure and Enthalpy Flash (PH Flash).'''
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|| 11:26
|| The '''variable''' at the end of the '''PropertyPackages.FlashSpec''' signifies which '''variable''' is used for '''flash''' calculation. 

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||11:35
|| Here in the first '''argument,''' we pass the '''Pressure''' and in the next we pass the '''Enthalpy.'''
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||11:43
|| With this, the '''Python script''' is completed.

Now we will run the '''simulation.'''
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|| 11:49
|| So, from the toolbar, click on '''Solve Flowsheet''' button.

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|| 11:53
||Switch to '''Flowsheet''' tab.
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|| 11:56
|| When the calculations are completed, click on the '''Mixed Product '''in the '''flowsheet'''.
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|| 12:01
|| Under '''Stream Conditions, '''check '''Temperature''', '''Pressure''' and '''Molar Flow'''.
|- 
|| 12:10
|| Let's summarize.
|- 
|| 12:12
|| In this tutorial, we have learnt to

|- 
||12:15
|| Create a custom unit operation using '''Python'''

|- 
||12:18
|| Calculate '''Overall mass '''and '''mole flow rate'''

|- 
||12:22
|| Calculate '''Enthalpy''' and '''outlet pressure'''
|- 
|| 12:26
|| As an assignment,

Create a custom model for a flash column to separate the gas-liquid phase for a mixture of compounds.

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|| 12:34
|| Calculate the amount of liquid and vapour generated at 0.075 bar.

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|| 12:40
|| Compare the results with in-built Gas-Liquid Separator available.
|- 
|| 12:45
|| Watch the video available at the following link.

It summarizes the Spoken Tutorial project.
|- 
|| 12:52
|| The Spoken Tutorial Project Team

Conducts workshops and Gives certificates.

|- 
||12:58
|| For more details, please write to us. 

|- 
|| 13:01
|| Please post your times queries in this forum.
|- 
|| 13:05
|| The '''FOSSEE''' team coordinates conversion of existing flow sheets into '''DWSIM.'''

|- 
|| 13:11
|| We give honorarium and certificates.

For more details, please visit this site.
|- 
|| 13:18
|| The '''FOSSEE''' team coordinates coding of solved examples of popular books.

|- 
|| 13:24
|| We give honorarium and certificates.

For more details, please visit this site.
|- 
|| 13:31
|| The '''FOSSEE''' team helps migrate commercial simulator labs to '''DWSIM.'''

|- 
|| 13:38
|| We give honorarium and certificates.

For more details, please visit this site.
|- 
|| 13:45
|| '''Spoken Tutorial''' and '''FOSSEE''' projects are funded by '''NMEICT, MHRD''', Government of India.
|- 
||13:53
|| This tutorial is contributed by Kaushik Datta and Priyam Nayak.

Thanks for joining.
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