Chemsep Database¶

Chemsep Databse is a library which hosts all the components of Chemsep Database along with their thermophysical properties to be used directly in Modelica language. There are 34 thermophysical properties which are available for the components listed under Chemsep Database.

All these thermophysical properties are defined as variables in the GeneralProperties model available under the package ChemsepDatabase.

General Properties¶

GeneralProperties model has been created to define the variables for all the thermophysical properties that are available for the components in Chemsep Database. These variables are to be remain constant during the course of simulation and therefore the keyword parameter is prefixed while defining the variables.

In this model, variables for the following constant thermophysical properties are defined:

Variables	Description	Units
SN	Serial Number	Not Applicable
name	Name of the Compound	Not Applicable
CAS	CAS ID	Not Applicable
Tc	Critical Temperature	K
Pc	Critical Pressure	Pa
Vc	Critical Volume	m3/kmol
Cc	Critical Compressibility Factor	No units
Tb	Boiling Point Temperature	K
Tm	Melting Point Temperature	K
TT	Triple Point Temperature	K
TP	Triple Point Pressure	Pa
MW	Molecular Weight	kg/kmol
LVB	Liquid Molar Volume at Normal Boiling Point	m3/kmol
AF	Accentric Factor	No units
SP	Solubility Parameter	J0.5/m1.5
DM	Dipole Moment	Columb.m
SH	Absolute Enthalpy	J/kmol
IGHF	Standard Heat of Formation	J/kmol
AS	Absolute Entropy	J/[kmol.K]
HFMP	Heat of Fusion at Melting Point	J/kmol
HOC	Heat of Combustion	J/kmol
UniquacR	UNIQUAC R	No Units
UniquacQ	UNIQUAC Q	No Units
Racketparam	Racket parameter	No Units
ChaoSeadAF	Chao-Seader Accentric Factor	No Units
ChaoSeadSP	Chao-Seader Solubility Parameter	J0.5/m1.5
ChaoSeadLV	Chao-Seader Liquid Volume	m3/kmol

Aditionally, array variables for the following temperature dependent properties are also defined.

Variables	Description	Units
LiqDen[6]	Liquid Density Coefficients	kmol/m3
VP[6]	Vapor Pressure Coefficients	Pa
LiqCp[6]	Liquid Heat Capacity Coefficients	J/[kmol.K]
HOV[6]	Heat of Vaporization Coefficients	J/kmol
VapCp[6]	Ideal Gas Heat Capacity Coefficients	J/[kmol.K]
LiqVis[6]	Liquid Viscosity Coefficients	Pa s
VapVis[6]	Vapor Viscosity Coefficients	Pa s
LiqK[6]	Liquid Thermal Conductivity Coefficients	W/[m.K]
VapK[6]	Vapor Thermal Conductivity Coefficients	W/[m.K]

The first indice of the array refers to the equation number from the Chemsep Database which is used to calculate the property value as function of temperature. Remaining indices are the actual coefficients that are used in the equation to calculate the property.

Every component of Chemsep Database is a separate model where the GeneralProperties model is then extended and then the property values are passed for the corresponding parameter variables.

For example, to define the thermophysical properties of component Air, the model Air is created as

model Air
...
extends GeneralProperties(SN = 1, name = "Air", CAS = "132259-10-0", Tc = 132.45, ...");
end Air;

While creating any unit operation model, GeneralProperties model of ChemsepDatabase must be instantiated so that the thermophysical properties of the components can be used and accessed by the unit operation model while using it during the course of simulation. This can be done by writing the below line of code

parameter Simulator.Files.ChemsepDatabase.GeneralProperties C[Nc];

Here, C[Nc] is an array variable which can be used to access all the thermophysical properties available in GeneralProperties model of ChemsepDatabase.

Using Components from Chemsep Database in a Simulation¶

Following are the steps that must be followed to use any component from ChemsepDatabase while creating a simulation:

1. First, ChemsepDatabase has to be imported and stored it in a variable. Here, it is stored in a variable called data. This can be done by writing the following line of code

import data = Simulator.Files.ChemsepDatabase;

2. Once the database is imported and stored in the variable data, then it can be called to create instances for the components required in the simulation. For example, if Methanol and Ethanol are the compounds to be used in the simulaation, its instances can be created by writing the following lines of codes

parameter data.Methanol meth;
parameter data.Ethanol eth;

Here, meth and eth are the instances created from the compound Methanol and Ethanol respectively.

3. Next step is to declare an integer variable to define the number of components to be used in the simulation. Here, varibale Nc is used to define the number of variables

parameter Interger Nc = 2;

4. Next step is to declare an array variable of size equal to number of components Nc and assign the general properties of the component instances created in step 2 to the array. Here, C is the array variable declared. This can be done by writing the following lines of code

parameter data.GeneralProperties C[Nc] = {meth, eth};