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Balances M&E Rutinas operaciones Diseño de Equipos SIMULACIÓN Equilibrio Fases Reacción Propiedades Termodinámicas CÁLCULO PROPIEDADES Propiedades Transporte Propiedades Intermedias Relaciones Termodinámicas ECUACIONES Ecuaciones numéricas Variables de operación (x i, P, T, V) Propiedades Puros PARÁMETROS Parámetros de mezclas Escalares Función T Binarios Ternarios Valores Experimentales Regresión Base de datos Usuario Estimación Models (Routes) Models Major Subordinate CÁLCULO DE PROPIEDADES FÍSICAS EN UN SIMULADOR ANÁLISIS Intermediate
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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
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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)
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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:
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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:
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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?
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Property Method Property Method: a collection of methods and models to evaluate physical properties and phase equilibrium. The first step is choosing the appropriate property method.
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Select a Property Model Template, General with metric units. /Data /Setup: Run Type Property Analysys /Data /Components: METHANOL, WATER /Data /Properties: Base Method NRTL
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/Properties / Property Methods /NRTL: Routes, Select HLMX, View View a ROUTE description Descripción en ENERGIA LIBRE NRTL.docx
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/Properties / Property Methods /NRTL: Models, Select GMRENON Check a MODEL F1 EJERCICIO: Explicar la ruta para calcular la entalpía molar de un componente puro en fase líquida cuando se selecciona el Property Package NRTL, con una mezcla Methanol+Agua
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Property Method Selection
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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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More about Property Methods... APrSystem Help: /Data /Properties [F1]
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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
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Model Parameters Reid,Prausnitz y Pooling, The Properties of Gases & Liquids, 4th Ed, Cap. 8, p. 380-1.
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