WILSON_K_VALUE

This function estimates the vapor-liquid equilibrium ratio for a component with Wilson’s correlation, commonly used to initialize flash and stability calculations.

The correlation is:

K_i = \frac{P_c}{P}\exp\left(5.37(1+\omega)\left[1-\frac{T_c}{T}\right]\right)

Excel Usage

=WILSON_K_VALUE(temperature, pressure, critical_temperature, critical_pressure, omega)

temperature (float, required): System temperature (K).
pressure (float, required): System pressure (Pa).
critical_temperature (float, required): Component critical temperature (K).
critical_pressure (float, required): Component critical pressure (Pa).
omega (float, required): Acentric factor (-).

Returns (float): Wilson-estimated equilibrium K-value.

Example 1: Ethane-like reference case

Inputs:

temperature	pressure	critical_temperature	critical_pressure	omega
270	7600000	305.4	4880000	0.098

Excel formula:

=WILSON_K_VALUE(270, 7600000, 305.4, 4880000, 0.098)

Expected output:

0.296393

Example 2: Lower pressure increases K-value

Inputs:

temperature	pressure	critical_temperature	critical_pressure	omega
270	101325	305.4	4880000	0.098

Excel formula:

=WILSON_K_VALUE(270, 101325, 305.4, 4880000, 0.098)

Expected output:

22.2313

Example 3: Methane-like component

Inputs:

temperature	pressure	critical_temperature	critical_pressure	omega
190	5000000	190.6	4604000	0.011

Excel formula:

=WILSON_K_VALUE(190, 5000000, 190.6, 4604000, 0.011)

Expected output:

0.905148

Example 4: Heavier component with larger omega

Inputs:

temperature	pressure	critical_temperature	critical_pressure	omega
370	3000000	540.2	2736000	0.349

Excel formula:

=WILSON_K_VALUE(370, 3000000, 540.2, 2736000, 0.349)

Expected output:

0.0325683

Python Code

Show Code

from chemicals.flash_basic import Wilson_K_value as chemicals_wilson_k_value

def wilson_k_value(temperature, pressure, critical_temperature, critical_pressure, omega):
    """
    Estimate a component equilibrium K-value using Wilson's correlation.

    See: https://chemicals.readthedocs.io/chemicals.flash_basic.html#chemicals.flash_basic.Wilson_K_value

    This example function is provided as-is without any representation of accuracy.

    Args:
        temperature (float): System temperature (K).
        pressure (float): System pressure (Pa).
        critical_temperature (float): Component critical temperature (K).
        critical_pressure (float): Component critical pressure (Pa).
        omega (float): Acentric factor (-).

    Returns:
        float: Wilson-estimated equilibrium K-value.
    """
    try:
        return chemicals_wilson_k_value(temperature, pressure, critical_temperature, critical_pressure, omega)
    except Exception as e:
        return f"Error: {str(e)}"

Online Calculator

temperature *

System temperature (K).

pressure *

System pressure (Pa).

critical_temperature *

Component critical temperature (K).

critical_pressure *

Component critical pressure (Pa).

omega *

Acentric factor (-).