Triple Effect Evaporator Simulation CHEN 4130 Senior Lab Fall 2007 MEMORANDUM for: Process Engineering Teams, CHEN 4130 From: The Instructors, CHEN 4130 The triple effect evaporator uses a saturated steam input to heat solutions to boiling. As the solvent is boiled off, the solution becomes more concentrated in each successive evaporator, and the boiling point elevation caused by the increase in solute concentration can become an important issue. Evaluate the flow rate needed to achieve a product composition of 15% (wt.) for the following feed stocks: 8% (wt.) sucrose / 92% (wt.) H2O and 8% (wt.)/ 92%(wt.) Na2OH. 1. Using AspenPlus or HYSYS, simulate the sucrose experiment using to specify the heat duty and pressure of each effect for the range of feed rates specified below. Note the heat duty and pressure of each effect. In reporting your investigations, please address the following items, including any additional points based upon your study of the problem: Compare the boiling point elevation when operating with sucrose and sodium hydroxide. Compare the results of your simulations with information from the literature. Discuss the operating conditions (Ti, Pi, qfeed, qcool,) needed to run the process with each solution. Simulate the operation with two effects at the same flow rate obtained in Part 1 above for both the aqueous sugar and sodium hydroxide feeds? Can it be operated in a countercurrent flow configuration? Can the unit be operated under vacuum? Would a vacuum configuration be helpful in reaching the target composition for any of the feeds? Aspen Plus and HYSYS Notes AspenPlus is available on the computers in the Borgmann Lab. HYSYS is available on the the computers in the Borgmann and ITLL-HP Labs. View the AspenPlus and HYSYS tutorials, which can be found on the web at: http://optimal.colorado.edu/aspen http://optimal.colorado.edu/hysys Use the University of Colorado Plus System to create your student accounts in the Magellan computing center. *HYSYS will be available on the computers in the Borgmann and ITLL-HP lab, but it is unable to model electrolytes. Consult with the instructor before attempting to use HYSYS. (HYSYS hint: each effect can be modeled using an appropriate combination of a cooler and a separator.) Operational Guidelines: Use a steam pressure of 30 psig. Do not exceed steam pressures of 40 psig. Use a feed flow rate from 0.2 to 0.4 gpm to achieve the targeted product for the sugar solution. Other data that may be useful for the sugar solution: Patm = ~13 psia T1 = ~122.1˚C Water Density: 998.23 kg/m3 at 20˚C Reference: Felder, R.M. and Rousseau, R.W., Elementary Principles of Chemical Processes, Wiley (1986).