Unformatted text preview: Homework 6 Problem 4 SuperPro Designer™ Batch Distillation
20 points possible due Monday October 10, 2011 Grader: Israel Problem Statement: A batch distillation column is to be used for fractionating a solvent mixture containing Acetone, Heptane, Water and small amounts of non‐volatile solutes (A, B, and C). The multicomponent feed to the column enters at a flowrate of 3226 kg/batch at 25oC and 1.013 bar. The feed compositions are shown below. A Mass Comp (%) 0.89 B 3.62 C 0.10 Acetone 68.29 Heptane 24.57 Water 2.53 Component It is desired to obtain a product with an acetone concentration of at least 99.85 mol percent with a reflux ratio of 2.0. Determine the minimum number of trays required for this process. The non‐volatile solute A has a molecular weight of 20 g/mol, B is 30 g/mol, and C is 31.98 g/mol. Method of Solution: Use the SuperPro Designer to simulate the batch process. Solution: 1) Open the SuperPro DesignerTM program. 2) Select “Batch Mode” and click OK. 3) To register the process components select Tasks → Pure Components →
Register, Edit/View Properties… from the toolbar. 4) Type acetone in the source box, highlight the appropriate component, and click the Register button in the center of the edit window. 5) Now add heptane to the selected component list. If you add a component by mistake, click on the component number and delete the selection by clicking the delete button in the upper right hand corner of the Registered Pure Components box. 6) Components that are not found in the SuperPro Designer databank must be added into the simulation by the user and are therefore considered user define components. To enter a user defined component, click the Add a New Component button , which is in the upper right hand corner of the Registered Pure Components box. Do so now to add components A, B and C. 7) The New Component Definition window will appear. Type in the component name A, which will automatically fill in the subsequent naming regions of this window, click OK. 8) Highlight component A and click the View/Edit the Selected Component Properties button . Under the Physical (Constant) tab, enter a molecular weight of 20 g/mol. 9) Repeat step 9 for component B, which has a molecular weight of 30 g/mol, and component C, which has a molecular weight of 31.98 g/mol. 10) Click OK to close the Register/Edit Pure Components window. Save the case. 11) Add a batch distillation column to the PFD from the Unit Procedures Distillation menu on the toolbar. 12) Connect feed and product streams to the distillation column by clicking the Connect Mode button like the one shown below: . The process flow diagram should now look 13) Change the name of stream S‐101 to Feed by clicking Edit → Stream Options → Edit Tag Name… Also, change the name of streams S‐102 to Vapor and S-103 to Liquid. 14) Double click on the Feed stream. Enter a flowrate of 3226 kg/batch, a temperature of 25oC, and a pressure of 1.013 bar. This stream contains 0.89% A, 3.62% B, 0.10% C, 68.29% acetone, 24.57% heptane and 2.53% water. When all specifications have been entered, click OK to exit. IMPORTANT NOTE – If gaseous components (e.g., O2, N2) are present in the feed to the distillation column, the distillation algorithm may take longer or even fail to converge. If you run into thatproblem, you may want to remove the gaseous components from the feed stream using a Component Splitter. 15) Right click the distillation column and select Operation Data… 16) Under the Operating Conditions tab, enter reboiler temperature of 70oC. This column takes 12 hours to complete the separation process and does not require any set up time. Components A, B, and C are non‐volatile. 17) Under the Operating Period tab, enter a reflux ratio of 2 with a 50% distillate rate, which will exit the column as the Vapor product stream. 18) The Profiles tab is used to generate a graph in Excel of component composition profiles throughout the column. For this simulation, generate a plot of time versus the molar compositions of acetone, heptane and water in the receiver and bottoms. 19) The distillation column is fully defined, click OK to close the data input window. 20) The process has been fully defined. Save the file. Click Task → Solve M&E Balances to run the process. 21) Open the Vapor product stream to check the simulation results. You should have the following compositions and flowrates. 22) The Liquid product stream should have the following compositions and flowrates. 23) To plot the composition results, right click the distillation column and select Dynamic Data Records… → DISTILL‐1 → Save in an Excel Formatted File… 24) Open the Excel file saved in the previous step. Locate the appropriate data and plot each component versus time in minutes. 25) Check the column specifications by right clicking on the column and select Equipment Data… Results/Considerations: SuperPro DesignerTM determined that in order to achieve a 99.86% acetone product in the vapor stream, a 5 tray batch distillation column is required for this process. A column with 4 trays will produce a 99.59% acetone product and 3 trays result in 98.87% acetone in the vapor stream. ...
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