Balances M&E

Rutinas operaciones

Diseño de Equipos

SIMULACIÓN

Equilibrio Fases

ReacciónPropiedades

Termodinámicas

CÁLCULO PROPIEDADES

Propiedades Transporte

Propiedades Intermedias

Relaciones Termodinámicas

ECUACIONES

Ecuaciones numéricas

Variables de operación(xi, P, T, V)

Propiedades Puros

PARÁMETROS

Parámetros de mezclas

Escalares

Función T

Binarios

Ternarios

Valores ExperimentalesRegresión

Base de datos

Usuario

Estimación

Models (Routes)

Models

Major

Subordinate

CÁLCULO DE PROPIEDADES FÍSICAS EN UN SIMULADOR ANÁLISIS

Intermediate

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

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)

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 expressionHLMX = f(T, P, x_i, parámetros)

METHOD 2: From the ideal liquid mixture enthalpy (Hi*L) y the excess

enthalpy (HEX).HLMX = Σxi Hi

*L + HEX

METHOD 3: From ideal gas mixture enthalpy (Hmig) and departure

enthalpy (Hdepart):HLMX = Hm

ig + Hdepart

METHOD 4: ElectrolytesHLMX = f(xTRUE)

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:

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:

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?

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.

Select a Property Model

• Template, General with metric units.•/Data /Setup: Run Type Property Analysys• /Data /Components: METHANOL, WATER• /Data /Properties: Base Method NRTL

FlowsheetProperty

EstimationProperty Analysis

Data Regression

Assay data analysis

Flowsheet simulation

Property constant estimation (PCES)

Properties tables calculation

Experimental data correlation

Oil fractions characterization

• /Properties / Property Methods /NRTL: Routes , Select HLMX, View

View a ROUTE description

Descripción en ENERGIA LIBRE NRTL.docx

• /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

Property Method Selection

• Main characteristic: phase equilibria calculation. Classification:

• IDEAL• EOS (PR, RK, BWR,....)• Activity coefficient (NRTL, UNIFAC, ...)• Electrolites (ELECNRTL, PITZER)• Special methods (AMINES, STEAMNBS,...)

• Selection: Help

1

2

3

More about Property Methods ... APrSystem Help: /Data /Properties [F1]

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

Model Parameters

Reid,Prausnitz y Pooling, The Properties of Gases & Liquids, 4th Ed, Cap. 8, p. 380-1.