NaCl Property Package with Temperature Dependence

This package implements property relationships for an NaCl solution.

This NaCl property package:
  • supports only H2O (solvent) and NaCl (solute) components

  • supports only liquid phase

  • is formulated on a mass basis

  • is intended for non-isothermal applications

  • does not support dynamics

Sets

Description

Symbol

Indices

Components

\(j\)

[‘H2O’, ‘NaCl’]

Phases

\(p\)

[‘Liq’]

State variables

Description

Symbol

Variable

Index

Units

Component mass flowrate

\(M_j\)

flow_mass_phase_comp

[p, j]

\(\text{kg/s}\)

Temperature

\(T\)

temperature

None

\(\text{K}\)

Pressure

\(P\)

pressure

None

\(\text{Pa}\)

Properties

Description

Symbol

Variable

Index

Units

Component mass fraction

\(x_j\)

mass_frac_phase_comp

[p, j]

\(\text{dimensionless}\)

Mass density

\(\rho\)

dens_mass_phase

[p]

\(\text{kg/}\text{m}^3\)

Phase volumetric flowrate

\(Q_p\)

flow_vol_phase

[p]

\(\text{m}^3\text{/s}\)

Volumetric flowrate

\(Q\)

flow_vol

None

\(\text{m}^3\text{/s}\)

Mass concentration

\(C_j\)

conc_mass_phase_comp

[p, j]

\(\text{kg/}\text{m}^3\)

Component mole flowrate

\(N_j\)

flow_mol_phase_comp

[p, j]

\(\text{mole/s}\)

Component mole fraction

\(y_j\)

mole_frac_phase_comp

[p, j]

\(\text{dimensionless}\)

Molality

\(Cm_{NaCl}\)

molality_comp

[‘NaCl’]

\(\text{mole/kg}\)

Solubility

\(x_{sat_{NaCl}}\)

solubility_comp

[‘NaCl’]

\(\text{dimensionless}\)

Vapor Pressure

\(P_{sat}\)

pressure_sat

None

\(\text{Pa}\)

Dynamic viscosity

\(\mu\)

visc_d_phase

[p]

\(\text{Pa/s}\)

Thermal Conductivity

\(k\)

therm_cond_phase

[p]

\(\text{W/m/K}\)

Specific Heat Capacity

\(C_p\)

cp_mass_phase

[p]

\(\text{J/kg/K}\)

Solute diffusivity

\(D\)

diffus_phase_comp

[p,’NaCl’]

\(\text{m}^2\text{/s}\)

Osmotic coefficient

\(\phi\)

osm_coeff

None

\(\text{dimensionless}\)

Osmotic pressure

\(\pi\)

pressure_osm

None

\(\text{Pa}\)

Specific enthalpy

\(\widehat{H}\)

enth_mass_phase

[p]

\(\text{J/kg}\)

Enthalpy flow

\(H\)

enth_flow

None

\(\text{J/s}\)

Relationships

Description

Equation

Component mass fraction

\(X_j = \frac{M_j}{\sum_{j} M_j}\)

Mass density

Equation 7 in Sparrow (2003)

Volumetric flowrate

\(Q = \frac{\sum_{j} M_j}{\rho}\)

Mass concentration

\(C_j = X_j \rho\)

Component mole flowrate

\(N_j = \frac{M_j}{MW_j}\)

Component mole fraction

\(y_j = \frac{N_j}{\sum_{j} N_j}\)

Molality

\(Cm_{NaCl} = \frac{x_{NaCl}}{(1-x_{NaCl}) MW_{NaCl}}\)

Solubility

Equation 5 in Sparrow (2003)

Vapor Pressure

Equation 6 in Sparrow (2003)

Dynamic viscosity

Regressed from Zaytsev & Aseev (1992)

Thermal Conductivity

Regressed from Zaytsev & Aseev (1992)

Specific Heat Capacity

Regressed from Zaytsev & Aseev (1992)

Solute diffusivity

Regressed from Zaytsev & Aseev (1992)

Osmotic coefficient

Regressed from Pitzer et. al. (1984)

Osmotic pressure

\(\pi = i \phi Cm_{NaCl} \rho_w R T\) [See note 1 below]

Specific enthalpy

Equation 8 in Sparrow (2003)

Enthalpy flow

\(H = \sum_{j} M_j \widehat{H}\)

Note 1: Osmotic pressure calculation uses the van ‘t Hoff factor (\(i\text{, assumed to be 2}\)), density of water (as a function of temperature), gas constant (\(R\text{, 8.314 J/mol}\text{K}\)) in addition to previously defined variables.

Scaling

This NaCl property package includes support for scaling, such as providing default or calculating scaling factors for almost all variables. The only variables that do not have scaling factors are the component mass flowrate and the user must set them or the user will receive a warning.

The user can specify the scaling factors for component mass flowrates with the following:

The default scaling factors are as follows:

  • 1e-2 for temperature

  • 1e-6 for pressure

  • 1e-3 for mass density

  • 1e3 for dynamic viscosity

  • 1e9 for solute diffusivity

  • 1 for the osmotic coefficient

  • 1e-5 for the specific enthalpy

  • 1e-4 for the specific heat capacity

  • 1e-5 for vapor pressure

  • 1 for thermal conductivity

  • 1 for solubility

The scaling factors for other variables can be calculated based on their relationships with the other variables with the user supplied or default scaling factors.

References

Pitzer, Kenneth S., J. Christopher Peiper, and R. H. Busey. (1984). Thermodynamic Properties of Aqueous Sodium Chloride Solutions, Journal of Physical and Chemical Reference Data 13, no. 1 , 1–102. DOI: 10.1063/1.555709

Sparrow, Benjamin S. (2003). Empirical Equations for the Thermodynamic Properties of Aqueous Sodium Chloride, Desalination 159, no. 2, 161–70. DOI: 10.1016/S0011-9164(03)90068-3

Zaytsev Ivan Dmitrievich & Aseev G. G. (1992). Properties of aqueous solutions of electrolytes, CRC Press.