Unformatted text preview: Homework 5 Problem 4 Aspen HYSYS™ Bubble Point Tutorial & Seider
Problem 5.15 p.149
20 points possible due Friday September 30, 2011 Grader: Israel Problem Statement: Following the tutorial determine the bubble point temperature, Tb, for a binary mixture of 80 mol% hexane and 20 mol% octane at 2 atm. Then complete problem 5.15 on page 149 of the Seider class textbook. Method of Solution: Use HYSYS to calculate the properties of a material stream at the given conditions. The temperature corresponding to a saturated liquid at the given composition is the bubble point temperature. Solution: 1) Open the HYSYSTM program: Start/ All Programs/AspenTech/Process Modeling
V7.2/Aspen HYSYS /Aspen HYSYS 2) Set the default units by selecting Tools / Preferences. In the Session Preferences window select the Variables tab and select SI in the Available Unit Sets box. 3) Open a new case by either clicking the New Case icon on the toolbar, or by selecting File / New / Case from the top menu bar. Page 1 of 9 4) The Simulation Basis Manager window will appear. First we must add a fluid property package to estimate the physical properties of our process components. Click on the Fluid Pkgs tab and then the Add… button. 5) Select the Peng‐Robinson equation of state from the Property Package Selection list. Now, let’s add our components. Click View (next to Component List Selection box) to open the Component List View window. 6) Now, let’s add our components. Click View to open the Component List View window. In the Match field, type “hexane”. Highlight “n‐Hexane”, and then click Add Pure to add it to the Selected Components List. Add normal octane in the same way, as shown below. Page 2 of 9 7) Once both components have been added, close the Component List View and Fluid Package windows by clicking the in the upper‐right‐hand corner of the window. [Notice that should appear under Current Fluid Packages; that is, the PR equation of state is to be used with 2 components.] 8) Click Enter Simulation Environment. 9) The PFD workspace will open. Notice the menu bar and tool bar functions. Also, the Object Palette should automatically appear in the workspace. If the Object Palette does not appear, open it by clicking the icon on the toolbar or pressing F4. 10) Add a material stream to the workspace by clicking on the blue arrow icon on the Object Palette (the red arrow corresponds to an energy stream) and then clicking again in the workspace. 11) Double‐click on the stream you just placed in the workspace. A window appears that allows you to specify the material stream. Type in the field next to Stream Name to name the stream “Hexane/Octane Mix”. Then press ENTER. Page 3 of 9 12) In the Vapour/Phase Fraction field input “0” since we want to determine the stream properties as a saturated liquid (the bubble point). Then press ENTER. 13) In the Pressure field input “2” and then use the drop down options to choose the appropriate units – atm. 14) To be fully specified, HYSYSTM also requires us to input a flow rate for the Hexane/Octane Mix. We can assume any flow rate without affecting the Page 4 of 9 temperature calculated for the stream; therefore, input a Mass Flow of 100 kg/h. Conditions option: Allows the
user to specify conditions (such as
T, P, flow rate, vapor fraction,
etc.) of the stream.
Composition option: Allows the
user to specify the composition of
the stream. 15) In most cases, when a material stream needs to be specified, the required information is input into the Conditions and Composition sections of the stream window. Since we have already specified the stream conditions, click on the Composition option on the left‐side of the window. Input “0.8” for the mole fraction of n‐Hexane. Press ENTER. An Input Composition window will appear. Complete inputting the given composition of the hexane‐octane mixture, as below. When finished, click OK. Notice the variety of ways that
stream compositions can be
entered. Since we were given
mole fractions in the problem
statement, we have the Mole
Fraction radio button selected.
However, sometimes it is more
convenient to enter composition
data using a different basis. Page 5 of 9 16) Your material stream should now be fully specified and converged. The status bar on the bottom of the window should turn green and display “OK”. 17) Open the Conditions section. Notice that the information that you specified is in blue, and the information that HYSYSTM has calculated is in black. Being able to recognize the information that you have entered versus that calculated will be important in more complex simulations. Also, if you close the stream window, you will see that the material stream has changed from a light shade of blue to a darker one. Light blue signifies a stream that is underspecified; dark blue indicates that a stream is fully specified and has converged. Under‐Specified Specified/Converged 18) Right‐click anywhere in the workspace, and select Add Workbook Table from the menu options. Page 6 of 9 19) Highlight the “Material Streams” option and click Select. Notice that a table displaying the conditions of the stream appears. Workbook tables are very useful for displaying results in HYSYSTM. 20) You can also add a title, your name, the date, etc. to the workspace by using the Text Annotation function. Click on the icon on the tool bar, and then click again to place the text box in the workspace. A Text Props View window appears where you can type the contents of your text box. When finished, click OK. To resize the text box, click the Size Mode icon on the tool bar, click on the text box, and modify to the desired dimensions. 21) Your final PFD should be similar to the figure below: Page 7 of 9 Tb = 99.9994 oC If you need to increase the number of significant figures shown in the workbook
table, open Tools/Preferences and select the Variables tab. Open the Formats
view on the left-hand side of the window and scroll to temperature. Click the Format button, enter 6 significant figures and click OK to save the
changes. Page 8 of 9 Close the Preferences window. Your workbook should automatically reflect the change. If the workbook does not automatically update, delete the table and repeat steps 18‐19 above. 22) To save your HYSYSTM file, select File/Save from the menu bar. 23) Complete problem 5.15 on page 149 of the Seider class textbook. Page 9 of 9 ...
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