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Unformatted text preview: Homework 1 Problem 5 SuperPro Designer™ Kinetic Fermentation 20 points possible due Friday September 2, 2011 Grader: Alan Problem Statement: Understanding cell growth rates and the effects of environmental conditions on growth is a key aspect of biological engineering. The most common and versatile method of cell growth analysis used throughout industry is batch fermentation in a bioreactor. The fermentation bioreactor enables cell growth to take place under well‐defined operating conditions. Below is a typical overall fermentation reaction. 100 Media + 70 Oxygen → 28 Biomass + 70 Carbon Dioxide + 10 Impurity + 2 MAB + 60 Water All of the feed streams enter the reactor at STP. 7,800 kg of water is fed to the reactor at a flowrate of 100 L/min with a setup time of 5 minutes. 380 kg of media is also fed to the reactor at a flowrate of 10 kg/min with a setup time of 20 minutes. This fermentation cycle occurs at a temperature of 37oC with a constant heat rate of 0.5oC/min. The calculated reaction rate refers to biomass formation (dX/dt) since biomass was selected as the Rate Reference Component with a max of 0.20 h‐1. Media is the only substrate with a Ks value of 35 mg/L. the reaction is first order in biomass and has an enthalpy of ‐3,697 kcal/kg at an oxygen reference temperature of 37oC. The product will be cooled to 5oC using glycol, which has a cooling rate of 0.5oC/min, and will be transferred out of the fermentor in a process time of 272 minutes. Determine the amount of time required to completely consume the reaction components and what is the rate limiting reactant for this system. Method of Solution: Use the SuperPro DesignerTM to simulate the batch process. Solution: 1) Open the SuperPro DesignerTM program and start a new process file. 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 biomass in the source box, highlight the appropriate component, and click the Register button in the center of the edit window. 5) Add carbon dioxide and sodium chloride to the selected component list. When adding these components a warning message will appear, click OK to ignore. Note: 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 the component impurity. 7) The New Component Definition window will appear. Type in the component name Impurity, which will automatically fill in the subsequent naming regions of this window, click OK to close. 8) Also add components MAB and media. 9) Click OK to close the Register/Edit Pure Components window. Save the case. 10) Add a fermentor to the PFD from the Unit Procedures BatchVessel Procedure menu on the toolbar. 11) Connect feed and product streams to the fermentor by clicking the Connect Mode button . Click in the empty PFD space and then click on an input arrow toadd a feed stream. Click on the output arrow and then in the empty PFD space to add a product stream. The process flow diagram should now look like the one shown below: 12) Change the name of stream S‐101 to Water by right clicking on the stream and select Edit Tag Name… Also, change the name of streams S‐102 to Media,
S-103 to Air, S-104 to Vent and S-105 to Broth. 13) Double click on the Water stream. Add water to the stream by highlighting . Enter a flowrate of 7,800 it and click the Register button, oC, and a pressure of 1.013 bar. Click OK to kg/batch, a temperature of 25
close. 14) The Media stream contains 5 kg/batch biomass and 375 kg/batch media also at 25oC and 1.013 bar. 15) Open the Air stream and click the Stock Mixtures radio button under the Registered Components box. Add air to the stream and click the Auto‐
Adjust radio button on the Total Flowrates box. Click OK to close the window. 16) Right click the fermentor and select Add/Remove Operations… 17) This process will require 2 charges, heating, kinetic fermentation, cooling and a transfer out. 18) Charge‐1: Water a. Right click the fermentor and select Charge‐1 from the Operation Data. b. Under the Oper. Cond’s tab, charge the Water stream with a mass of 7,800 kg, with a setup time of 5 minutes, and a volumetric flowrate of 100 L/min. c. Click the Next Operation button input sheet. to go to the next operation 19) Charge‐2 using the Media stream with a mass of 380 kg, a setup time of 20 minutes, and a mass flowrate of 10 kg/min. Click the Next Operation button to go to the next operation input sheet. 20) For the heating cycle, the fermentor should reach a temperature of 37°C with a constant heat rate of 0.50°C/minute and no set up time required. Click the Next Operation button to go to the next input sheet. 21) Kinetic Fermentation a. The operating conditions tab should remain the same with a final temperature of 37°C, no setup time, a 24 hour reaction time, and a specific power of 3 kW/m3. b. Click on the Volumes tab, enter a maximum allowable vessel volume of 90%. c. Add a stoichiometric reaction to the case by clicking the Edit button under the Reactions tab. Stoichiometry
i. The reaction for this case based on mass coefficients is: 100 Media + 70 Oxygen → 28 Biomass + 70 Carbon Dioxide + 10 Impurity + 2 MAb + 60 Water Add the components to the appropriate reactants or products box by clicking the button and selecting the component from the dropdown menu. The Stoichiometric Coefficients radio button should be set on mass coefficients. Enter the reaction stoichiometry. Click OK to close the reaction window and save the changes. ii. This reaction has an enthalpy of ‐3,697 kcal/kg. Uncheck the Ignore Reaction Heat radio button and enter the enthalpy. The oxygen reference temperature is 37oC. iii. Click the button in the Reaction Scheme box to open the kinetic equation window. Select media as the substrate using a Monad equation with a Ks of 35 mg/L. The reference component for this reaction is biomass with a max of 0.2 h‐1. The reaction is 1st order in biomass. Click OK to save and close the kinetic fermentation window. d. Under the Vent/Emissions tab, check the Emissions radio button to perform emission calculations. Then select carbon dioxide for emission calculations and enter a rate of 100%. Turnoff the vent condenser. e. The Profiles tab is used to collect data during the simulation, which can later be used to plot compositions in Excel. Open that tab and select store concentration of biomass, MAb, and media data to be stored. f. The fermentation cycle has been fully defined. Click OK to save the input and close the FERMENT‐1 window. 22) Save the case before moving on to the next operation step to prevent loss of data. 23) Right click the fermentor and select Cool‐1 from the Operation Data. 24) Enter a final temperature of 5°C to be cooled with glycol with a cooling rate of 0.50°C/min for the Cooling step. Click the Next Operation button to go to the next input sheet. 25) Transfer out 100% of the vessel contents over 272 minutes in the broth stream. This step will not require any setup time. 26) The process has been fully defined, click OK to save and close the Operation Data window. 27) Save the file before proceeding. 28) Click Task → Solve M&E Balances or the button from the toolbar to run the process. 29) Open the Vent product stream to check the simulation results. You should have similar compositions and flowrates as those shown in the figure below: 30) The Broth product stream should have the following compositions and flowrates: 31) To plot the composition results, right click on the fermentation unit and select Dynamic Data Records… → FERMENT‐1 → Save in an Excel Formatted File… If the following prompt arrears, click yes to proceed. Save the Excel file. 32) Open the Excel file, select the data and plot each component concentration in g/L versus time in hours. The MAb concentration is easier to see is placed on the secondary y‐axis since it only ranges from 0 to 1 g/L. 33) Back in SuperPro Designer™, right click on the fermentation unit and select Procedure Data… to see the cycle time calculated by SuperPro DesignerTM for this process. As shown below, this fermentation cycle requires 32.44 hours. 34) Select Reports → Materials & Streams from the toolbar to view and print a full report of the process results. Results/Considerations: This reaction is complete after 15.6 hours at which time the concentration of media is zero. Thus, media is the rate limiting reactant for this process. ...
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This note was uploaded on 11/14/2011 for the course CHEN 4520 taught by Professor Wiemer during the Fall '11 term at Colorado.
- Fall '11