Properties of Gases and Liquids 4th edition (RPP4)

Source

Methods for calculating pure component properties from:

The Properties of Gases & Liquids, 4th Edition Reid, Prausnitz and Polling, 1987, McGraw-Hill

All methods use SI units.

Ideal Gas Molar Heat Capacity (Constant Pressure)

Properties of Gases and Liquids uses the following correlation for the ideal gas molar heat capacity:

\[c_{\text{p ig}} = A + B \times T + C \times T^2 + D \times T^3\]

Parameters

Symbol	Parameter Name	Units	Description
\(A\)	cp_mol_ig_comp_coeff_A	\(\text{J/mol}\cdotp\text{K}\)
\(B\)	cp_mol_ig_comp_coeff_B	\(\text{J/mol}\cdotp\text{K}^2\)
\(C\)	cp_mol_ig_comp_coeff_C	\(\text{J/mol}\cdotp\text{K}^3\)
\(D\)	cp_mol_ig_comp_coeff_D	\(\text{J/mol}\cdotp\text{K}^4\)

Ideal Gas Molar Enthalpy

The correlation for the ideal gas molar enthalpy is derived from the correlation for the molar heat capacity and is given below:

\[h_{\text{ig}} - h_{\text{ig ref}} = A \times (T-T_{ref}) + \frac{B}{2} \times (T^2 - T_{ref}^2) + \frac{C}{3} \times (T^3 - T_{ref}^3) + \frac{D}{4} \times (T^4 - T_{ref}^4) + \Delta h_{\text{form, Vap}}\]

Parameters

Symbol	Parameter Name	Units	Description
\(A\)	cp_mol_ig_comp_coeff_A	\(\text{J/mol}\cdotp\text{K}\)
\(B\)	cp_mol_ig_comp_coeff_B	\(\text{J/mol}\cdotp\text{K}^2\)
\(C\)	cp_mol_ig_comp_coeff_C	\(\text{J/mol}\cdotp\text{K}^3\)
\(D\)	cp_mol_ig_comp_coeff_D	\(\text{J/mol}\cdotp\text{K}^4\)
\(\Delta h_{\text{form, Vap}}\)	enth_mol_form_vap_comp_ref	Base units	Molar heat of formation at reference state

Note

This correlation uses the same parameters as the ideal gas heat capacity correlation. Units of molar heat of formation will be derived from the base units defined for the property package.

Ideal Gas Molar Entropy

The correlation for the ideal gas molar entropy is derived from the correlation for the molar heat capacity and is given below:

\[s_{\text{ig}} = A \times ln(T/T_{ref}) + B \times (T - T_{ref}) + \frac{C}{2} \times (T^2 - T_{ref}^2) + \frac{D}{3} \times (T^3 - T_{ref}^3) + s_{\text{form, Vap}}\]

Parameters

Symbol	Parameter Name	Units	Description
\(A\)	cp_mol_ig_comp_coeff_A	\(\text{J/mol}\cdotp\text{K}\)
\(B\)	cp_mol_ig_comp_coeff_B	\(\text{J/mol}\cdotp\text{K}^2\)
\(C\)	cp_mol_ig_comp_coeff_C	\(\text{J/mol}\cdotp\text{K}^3\)
\(D\)	cp_mol_ig_comp_coeff_D	\(\text{J/mol}\cdotp\text{K}^4\)
\(s_{\text{form, Vap}}\)	entr_mol_form_vap_comp_ref	Base units	Standard molar entropy of formation at reference state

Note

This correlation uses the same parameters as the ideal gas heat capacity correlation . Units of molar entropy of formation will be derived from the base units defined for the property package.

Saturation (Vapor) Pressure

Properties of Gases and Liquids uses the following correlation to calculate the vapor pressure of a component:

\[ln(\frac{P_{sat}}{P_{crit}}) \times (1-x) = A \times x + B \times x^1.5 + C \times x^3 + D \times x^6\]

where \(x = 1 - \frac{T}{T_{crit}}\).

Symbol	Parameter Name	Units	Description
\(A\)	pressure_sat_comp_coeff_A	None
\(B\)	pressure_sat_comp_coeff_B	None
\(C\)	pressure_sat_comp_coeff_C	None
\(D\)	pressure_sat_comp_coeff_D	None
\(P_{crit}\)	pressure_crit_comp	Same as system pressure	Critical pressure
\(T_{crit}\)	temperature_crit_comp	Same as system temperature	Critical temperature

Note

This correlation is only valid at temperatures below the critical temperature. Above this point, there is no real solution to the equation.