Skip to content

polykin.properties.vaporization_enthalpy¤

DHVL_Pitzer ¤

DHVL_Pitzer(T: float, Tc: float, w: float) -> float

Calculate the enthalpy of vaporization of a pure compound at a given temperature, \(\Delta H_v(T)\), using the Pitzer acentric factor method.

\[ \frac{\Delta H_v}{R T_c}=7.08(1-T_r)^{0.354} + 10.95 \omega (1-T_r)^{0.456} \]

where \(T_c\) is the critical temperature and \(T_r=T/T_c\) is the reduced temperature, and \(\omega\) is the acentric factor. The equation is valid in the range \(0.6<T_r<1\).

References

  • RC Reid, JM Prausniz, and BE Poling. The properties of gases & liquids 4th edition, 1986, p. 220.
PARAMETER DESCRIPTION
T

Temperature. Unit = K.

TYPE: float

Tc

Critical temperature. Unit = K.

TYPE: float

w

Acentric factor.

TYPE: float

RETURNS DESCRIPTION
float

Vaporization enthalpy. Unit = J/mol.
See also

Examples:

Estimate the vaporization enthalpy of vinyl chloride at 50°C.

>>> from polykin.properties.vaporization_enthalpy import DHVL_Pitzer
>>> DHVL = DHVL_Pitzer(T=273.15+50, Tc=425., w=0.122)
>>> print(f"{DHVL/1e3:.1f} kJ/mol")
17.5 kJ/mol
Source code in src/polykin/properties/vaporization_enthalpy.py 
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
def DHVL_Pitzer(T: float,
                Tc: float,
                w: float
                ) -> float:
    r"""Calculate the enthalpy of vaporization of a pure compound at a given
    temperature, $\Delta H_v(T)$, using the Pitzer acentric factor method.

    $$
    \frac{\Delta H_v}{R T_c}=7.08(1-T_r)^{0.354} + 10.95 \omega (1-T_r)^{0.456}
    $$

    where $T_c$ is the critical temperature and $T_r=T/T_c$ is the reduced
    temperature, and $\omega$ is the acentric factor. The equation is valid in
    the range $0.6<T_r<1$.

    **References**

    *   RC Reid, JM Prausniz, and BE Poling. The properties of gases & liquids
        4th edition, 1986, p. 220.

    Parameters
    ----------
    T : float
        Temperature. Unit = K.
    Tc : float
        Critical temperature. Unit = K.
    w : float
        Acentric factor.

    Returns
    -------
    float
        Vaporization enthalpy. Unit = J/mol.

    See also
    --------
    * [`DHVL_Kistiakowsky_Vetere`](DHVL_Kistiakowsky_Vetere.md): alternative method.
    * [`DHVL_Vetere`](DHVL_Vetere.md): alternative method.

    Examples
    --------
    Estimate the vaporization enthalpy of vinyl chloride at 50°C.
    >>> from polykin.properties.vaporization_enthalpy import DHVL_Pitzer
    >>> DHVL = DHVL_Pitzer(T=273.15+50, Tc=425., w=0.122)
    >>> print(f"{DHVL/1e3:.1f} kJ/mol")
    17.5 kJ/mol
    """
    Tr = T/Tc
    return R*Tc*(7.08*(1 - Tr)**0.354 + 10.95*w*(1 - Tr)**0.456)