DIP_10.ppt p. 1 Diseño Integrado de Procesos (Simulador) DIP 10.ppt Separation of a mixture of methanol + water Property Method Selection Model parameters Experimental data correlation Optimization Columns specifications

DIP_10.ppt p. 2 Diseño Integrado de Procesos (Simulador) The problem... Separate a 100 kmol/h stream mixture of methanol + water in an atmospheric column. Property Method: a collection of methods and models to evaluate physical properties and phase equilibrium. The first step is choosing the appropriate property method.

DIP_10.ppt p. 3 Diseño Integrado de Procesos (Simulador) Property Method Selection

DIP_10.ppt p. 4 Diseño Integrado de Procesos (Simulador) Main characteristic: phase equilibria calculation. Classification: IDEAL EOS (PR, RK, BWR,....) Activity coefficient (NRTL, UNIFAC,...) Electrolites (ELECNRTL, PITZER) Special methods (AMINES, STEAMNBS,...) Selection: Help

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DIP_10.ppt p. 6 Diseño Integrado de Procesos (Simulador) 1

DIP_10.ppt p. 7 Diseño Integrado de Procesos (Simulador) 2

DIP_10.ppt p. 8 Diseño Integrado de Procesos (Simulador) 3

DIP_10.ppt p. 9 Diseño Integrado de Procesos (Simulador) More about Property Methods... APrSystem Help: /Data /Properties [F1]

DIP_10.ppt p. 10 Diseño Integrado de Procesos (Simulador) Separation of a mixture of methanol + water in an atmospheric column: Open a new file (General with metric units) and define components (METHANOL, WATER) and Property Method (NRTL). Polar ? Electrolyte ? Yes P < 10 bar ? No ij ? Yes LL ? Yes Wilson, NRTL, UNIQAC No

DIP_10.ppt p. 11 Diseño Integrado de Procesos (Simulador) How does the Property Method calculate a specific property? The properties used in the simulation are classified into categories depending on how they are evaluated: Some general concepts: 1.MODELS 2.METHODS 3.ROUTES

DIP_10.ppt p. 12 Diseño Integrado de Procesos (Simulador) How does the Property Method calculate a specific property? The properties used in the simulation are classified into categories depending on how they are evaluated: 1. MODELS: models calculate properties by direct use of an empirical expression or a theoretical model. For example: GAMMA: liquid mixture activity coefficients. Possible MODELS:GMRENON:NRTL original GMUFAC:UNIFAC GMUFDMD:UNIFAC, modif. Dormund.... (up to 32 MODELS)

DIP_10.ppt p. 13 Diseño Integrado de Procesos (Simulador) 2. METHODS: in this case the property is evaluated using a thermodynamic expression where required properties are evaluated with MODELS. Different thermodynamic expressions (METHODS) may be available to evaluate a specific property. For example, four METHODS are available to evaluate the enthalpy of a liquid mixture (HLMX) : METHOD 1:Empiric expression HLMX = f(T, P, x_i, parámetros) METHOD 2:From the ideal liquid mixture enthalpy (H i *L ) y the excess enthalpy (H EX ). HLMX = Σx i H i *L + H EX METHOD 3:From ideal gas mixture enthalpy (H m ig ) and departure enthalpy (H depart ): HLMX = H m ig + H depart METHOD 4:Electrolytes HLMX = f(x TRUE ) How does the Property Method calculate a specific property? The properties used in the simulation are classified into categories depending on how they are evaluated:

DIP_10.ppt p. 14 Diseño Integrado de Procesos (Simulador) 3. ROUTES: The group of specific METHOD and MODELS selected to evaluate a property is named a ROUTE. How does the Property Method calculate a specific property? The properties used in the simulation are classified into categories depending on how they are evaluated:

DIP_10.ppt p. 15 Diseño Integrado de Procesos (Simulador) /Properties / Property Methods /NRTL: Routes, Select HLMX, View View a ROUTE description

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DIP_10.ppt p. 17 Diseño Integrado de Procesos (Simulador) Types of properties depending on their use and how they are calculated: MAJOR: Are those properties required for calculations by unit operation models. They ere evaluated according to ROUTES, and may depend on other MAJOR, SUBORDINATE and INTERMEDIATE properties. Properties: PHI, H, G, S, V, MU, K, D, SIGMA (Pure and mixtures) SUBORDINATE: these properties are also calculated using ROUTES, but are not directly required for unit operation model calculations. They are used to calculate MAJOR properties. Ex.: HLXS (excess enthalpy),... INTERMEDIATE: calculated by MODELS, they are used to calculate MAJOR and SUBORDINATE properties. Ex.: GAMMA (activity coefficients),... How does the Property Method calculate a specific property?

DIP_10.ppt p. 18 Diseño Integrado de Procesos (Simulador) /Properties / Property Methods /NRTL: Models, Select GMRENON Check a MODEL F1

DIP_10.ppt p. 19 Diseño Integrado de Procesos (Simulador) Model Parameters Reid,Prausnitz y Pooling, The Properties of Gases & Liquids, 4th Ed, Cap. 8, p

DIP_10.ppt p. 20 Diseño Integrado de Procesos (Simulador) The recommended order of use of the parameters (the same one used by Aspen): 1) experimental values (parameters or data correlation) 2) bibliographic (literature or Aspen database) 3) Estimates (PCES) Points 2 and 3 have already been presented in previous classes. Check parameters: /Properties /Parameters /Binary interaction /NRTL-1 Check residuals from correlation (press button [Reg. Info] after selecting the parameter) Check parameters available from other Databanks.

DIP_10.ppt p. 21 Diseño Integrado de Procesos (Simulador) Add a second model (/Properties /Specifications: Referenced -> WILSON) and compare residuals with NRTL model (F1).

DIP_10.ppt p. 22 Diseño Integrado de Procesos (Simulador) Experimental data correlation Correlate equilibrium TXY values at 760 mmHg: Ramalho R.S. et al, Ind.Eng.Chem. 53, 89 (1961) Change Run Type in Setup form to Data Regression. /Properties /Data: New ID: D-1 Select type: MIXTURE Write literature citation in the comments form Write data

DIP_10.ppt p. 23 Diseño Integrado de Procesos (Simulador) /Properties /Regression: New

DIP_10.ppt p. 24 Diseño Integrado de Procesos (Simulador) Help on NRTL parameters (F1)

DIP_10.ppt p. 25 Diseño Integrado de Procesos (Simulador) Modify the selection of parameters to be regressed: a ij = 0 b ij regress c ij = 0.30 Metanol+Agua_01.apw

DIP_10.ppt p. 26 Diseño Integrado de Procesos (Simulador) Run: confirm parameters replacement when asked. Metanol+Agua_02.apw

DIP_10.ppt p. 27 Diseño Integrado de Procesos (Simulador) NRTL parameters have been replaced in /Properties /Parameters /Binary Interaction /NRTL-1

DIP_10.ppt p. 28 Diseño Integrado de Procesos (Simulador) Plot using Plot Wizard from form: /Regression /R-1 /Results: Profiles

DIP_10.ppt p. 29 Diseño Integrado de Procesos (Simulador) Check other results in /Regression /R-1 /Results

DIP_10.ppt p. 30 Diseño Integrado de Procesos (Simulador) Selection criteria: Choose the model giving the lowest Residual Root Mean Square. Non-trustable regressions: A standard deviation for a regressed parameter is 0.0, indicating the parameter is at a bound. A large residual root mean square error value. Normally, this value should be less than 10 for VLE data and less than 100 for LLE data. Your VLE data fail the thermodynamic consistency test.

DIP_10.ppt p. 31 Diseño Integrado de Procesos (Simulador) Optimization /Setup: Run Type -> Flowsheet. Draw PFD, stream 1 and column. It is intended to separate a 100 kmol/h stream containing a mixture of MeOH + water (60 mol% MeOH). The mixture is 1 bar and it is at its boiling point. Use first a shortcut (DSTWU) to design a tower with a recovery of 99% for further optimization. Corriente 1 Metanol+Agua_03.apw

DIP_10.ppt p. 32 Diseño Integrado de Procesos (Simulador) Results...

DIP_10.ppt p. 33 Diseño Integrado de Procesos (Simulador) Operation will be optimized using an objective function to minimize total costs:, where N is the number of theoretical stages, Q B the reboiler duty, Q C the condenser duty and LKR is the light key recovery. Perform a sensitivity analysis to study the behavior of the tower prior to the optimization. /Model Analysis Tools /Sensitivity: New, S-1

DIP_10.ppt p. 34 Diseño Integrado de Procesos (Simulador) Results: Metanol+Agua_04.apw

DIP_10.ppt p. 35 Diseño Integrado de Procesos (Simulador) /Model Analysis Tools /Sensitivity: S-1, Hide /Model Analysis Tools /Optimization: New, O-1 Optimization:

DIP_10.ppt p. 36 Diseño Integrado de Procesos (Simulador) /Convergence/Convergence/$OLVER01/Results Metanol+Agua_05.apw

DIP_10.ppt p. 37 Diseño Integrado de Procesos (Simulador) NOTE: although the optimization block is hidden (Hide) or deleted (Delete) the value of the optimized variable is preserved, if not Reinitialize' is performed. This is because the optimized value of the variable is retained in the results form. /Blocks /D-110 /Input/Blocks /D-110 /Results

DIP_10.ppt p. 38 Diseño Integrado de Procesos (Simulador) /Model Analysis Tools /Optimization: O-1 -> Hide Write calculated design and operating variables: 31 stages, feed stage=20, D/F=0.598, RR= Change to RADFRAC /Setup /Report Options /Stream: Fraction Basis – Mole: ON Replace the shortcut (DSTWU) for a rigorous (RADFRAC) unit operation. Resultados Metanol+Agua_06.apw

DIP_10.ppt p. 39 Diseño Integrado de Procesos (Simulador) /Blocks /D-110 /Design Specs: New = 1 Specify 99.2% mol MeOH in stream 2 Let's see now, forgetting the optimization, how purity may be specified in distillate and bottoms, allowing the software evaluate operating variables. /Blocks /D-110 /Design Specs /1

DIP_10.ppt p. 40 Diseño Integrado de Procesos (Simulador) /Blocks /D-110 /Vary: New = 1 Allow RR vary between 0.1 y 10 /Blocks /D-110 /Vary /1 Run /Blocks /D-110 /Design Spec /1/Blocks /D-1101 /Vary /1 Metanol+Agua_07.apw

DIP_10.ppt p. 41 Diseño Integrado de Procesos (Simulador) /Blocks /D-110 /Design Specs: New = 2 Specify 99% mol WATER in stream 3 Specify now 99% mol WATER in stream 3, varying another column specification /Blocks /D-110 /Design Specs /2 /Blocks /D-110 /Vary /2 Metanol+Agua_08.apw

DIP_10.ppt p. 42 Diseño Integrado de Procesos (Simulador) /Blocks /D-110 /Vary /2 /Blocks /D-110 /Results/Blocks /D-110 /Stream Results