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Introduction to Aspen Plus. Speaker: Zong -Yan Li( 李宗諺 ) r07524013@ntu.edu.tw PSE Laboratory Department of Chemical Engineering National Taiwan University ( 化工館 RM307, 02-33663068). Editors : 程建凱 / 吳義章 / 余柏毅 / 陳怡均 / 潘晧 人 / 李宗諺 Figures in the slides are based on Aspen Plus V10. Outline.
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Introduction to Aspen Plus Speaker: Zong-Yan Li(李宗諺) r07524013@ntu.edu.tw PSE Laboratory Department of Chemical Engineering National Taiwan University (化工館RM307,02-33663068) Editors : 程建凱/吳義章/余柏毅/陳怡均/潘晧人/李宗諺 Figures in the slides are based on Aspen Plus V10
Outline • Part 1 : Introduction and start-up Aspen Plus software • Part 2 : Properties analysis 2-1: Select compounds needed 2-2: Select thermodynamics model 2-3: Plotting phase diagram/ thermodynamics validation 2-4: System without build-in parameter • Part 3 : “Mixing-heating” process simulation • Part 4 : Reaction simulation • Part 5 : Simple distillation simulation • Part 6 : Separating azeotrope: Pressure Swing Distillation (PSD)
Part 1 Introduction & start-up of Aspen Plus software
What course Aspen Plus can be employed for • MASS AND ENERGY BALANCES • PHYSICAL CHEMISTRY • CHEMICAL ENGINEERING THERMODYNAMICS • CHEMICAL REACTION ENGINEERING • UNIT OPERATIONS • PROCESS DESIGN • PROCESS CONTROL
How Aspen Plus Work Process Inlet(s) Mass balance Energy balance Thermodynamics User define models outlet(s) Simulate a process based on principles above
Initializing Aspen Plus AspenTech>>Aspen Plus>>Aspen Plus V10
Guideline for starting a simulation Select chemical compound in the system we want to simulate Select suitable thermodynamics model to describe the system Try your best to validate thermodynamic data First rule of simulation: Garbage in, garbage out
Part 2 Property analysis
2-1 Select compounds needed Example: water & n-butanol (n-BUOH) mixture system 1 2 • Every compound with “water” appears in its name shows in searching result • Choose “Equals” instead!
Searching with compound name 1 2 Double click on the compound Or click “Add selected compounds” • Searching with chemical formula
Select n-butanol (n-BUOH) Add n-butanol, not replace You can change Component ID (name appears in simulation)
Example: Building Dimethyl Adipate (DIMA) Find DIMA (Dimethyl Adipate)
Example: Building Dimethyl Adipate (DIMA) No DIMA in the databanks
Example: Building Dimethyl Adipate (DIMA) • Check NIST chemistry webbook for those information you need to build a user defined component. (http://webbook.nist.gov/chemistry/) Searching Method
Example: Building Dimethyl Adipate (DIMA) Searching for DIMA
Example: Building Dimethyl Adipate (DIMA) All information you can find in NIST Download the 2-d molecular structure file
Example: Building Dimethyl Adipate (DIMA) Import the 2-d molecular file you downloaded from NIST
Example: Building Dimethyl Adipate (DIMA) (Calculate bond for UNIFAC model estimation)
Example: Building Dimethyl Adipate (DIMA) Check the formula again. Then the component is successfully built.
2-2 Select Thermodynamics Model Choose suitable model to describe behavior of liquid/gas phase Relationship between pressure/temperature/volume of gas Phase diagram of liquid mixture EOS: Equation of State (ex: Van der Waal equations)
Typical Equation of States Peng-Robinson (PR) EOS Redlich-Kwong (RK) EOS Haydon O’Conell (HOC) EOS
Typical Activity Coefficient Models Non-Random-Two Liquid Model (NRTL) UNIQUAC Model UNIFAC Model
Water & BuOH: polar compounds • Choose activity coefficient model; NRTL in this demonstration to describe liquid phase • Select NRTL in Methods: use ideal gas law to describe vapor phase 1 2
Check parameter pairs: • For N components system, there should be pairs of binary parameters 3 See one binary parameter set Red semicircle turns to blue circle with check 2 1 Click on red semicircle
2-3 Plotting Phase Diagram/ Thermodynamics Validation Analysis Binary Txy or Pxy Define x-axis
T-xy diagram for WATER/BUOH 118 x 1.0133 bar y 1.0133 bar 116 114 112 110 108 106 Temperature, K 104 102 100 98 96 94 92 0.000 0.025 0.050 0.075 0.100 0.125 0.150 0.175 0.200 0.225 0.250 0.275 0.300 0.325 0.350 0.375 0.400 0.425 0.450 0.475 0.500 0.525 0.550 0.575 0.600 0.625 0.650 0.675 0.700 0.725 0.750 0.775 0.800 0.825 0.850 0.875 0.900 0.925 0.950 0.975 1.000 Liquid/vapor mole fraction, WATER You can set unit of temperature/pressure (Please switch the temperature unit to K for next step) Liquid-liquid-vapor Phase equilibrium
Experimental Data Validation 1 2 3 4
1 Choose one experimental data Then double click on it (later in year; more data point) 2 Look up “Binary VLE”Isobaric (Txy plot)
2 3 1
Now the data have been saved! Click “T-xy” in “Plot” • T-xy diagram for WATER/BUOH • Temperature, K • Liquid/vapor mole fraction, WATER
Merge two plot (simulation/exp. data) 2 1 Switch to exp. data Txy plot Merge plots 3 You will see a plot with 2 y-axis; use “Y axis map” to merge them 4
T-xy diagram for WATER/BUOH 392 x 1.0133 bar y 1.0133 bar 390 Exp. y BVLE067 (101300 N/sqm) Exp. x BVLE067 (101300 N/sqm) 388 386 384 382 380 Temperature, K 378 376 374 372 370 368 366 364 0.000 0.025 0.050 0.075 0.100 0.125 0.150 0.175 0.200 0.225 0.250 0.275 0.300 0.325 0.350 0.375 0.400 0.425 0.450 0.475 0.500 0.525 0.550 0.575 0.600 0.625 0.650 0.675 0.700 0.725 0.750 0.775 0.800 0.825 0.850 0.875 0.900 0.925 0.950 0.975 1.000 Liquid/vapor mole fraction, WATER Simulation data fit the exp. ones fairly well!
Save the Simulation File Save the file in Aspen Plus Documents (.apw)
Error demonstration: If we intentionally delete the thermodynamics parameters… Aspen Plus treat the liquid phase as ideal liquid mixture Bad simulation result!
2-4 System without Build-in Parameter Practice: open a new file and choose glycerol, water, acetic acid (HAC)
Choose “NRTL-HOC” thermodynamics model Method filter: ALL NRTL-HOC: Use NRTL model to describe the liquid phase Use HOC equation of state to describe behavior of carboxylic acid dimer (acetic acid in this case)in gas phase
Check parameters… 3-components system: should have 3 sets of parameter, but no build-in parameter for GLYCEROL and HAC… “Required Properties Input Complete” still be at lower-left corner!