VLE#

class VLE(imol=None, thermal_condition=None, thermo=None, bubble_point_cache=None, dew_point_cache=None)[source]#

Create a VLE object that performs vapor-liquid equilibrium when called.

Parameters:

  • imol=None (MaterialIndexer, optional) – Molar chemical phase data is stored here.

  • thermal_condition=None (ThermalCondition, optional) – Temperature and pressure results are stored here.

  • thermo=None (Thermo, optional) – Themodynamic property package for equilibrium calculations. Defaults to thermosteam.settings.get_thermo().

  • bubble_point_cache=None (Cache, optional) – Cache to retrieve bubble point object.

  • dew_point_cache=None (Cache, optional) – Cache to retrieve dew point object

Examples

First create a VLE object:

>>> from thermosteam import indexer, equilibrium, settings
>>> settings.set_thermo(['Water', 'Ethanol', 'Methanol', 'Propanol'], cache=True)
>>> imol = indexer.MolarFlowIndexer(
...             l=[('Water', 304), ('Ethanol', 30)],
...             g=[('Methanol', 40), ('Propanol', 1)])
>>> vle = equilibrium.VLE(imol)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Methanol', 40), ('Propanol', 1)],
        l=[('Water', 304), ('Ethanol', 30)]),
    thermal_condition=ThermalCondition(T=298.15, P=101325))

Equilibrium given vapor fraction and pressure:

>>> vle(V=0.5, P=101325)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 126.7), ('Ethanol', 26.38), ('Methanol', 33.49), ('Propanol', 0.8958)],
        l=[('Water', 177.3), ('Ethanol', 3.622), ('Methanol', 6.509), ('Propanol', 0.1042)]),
    thermal_condition=ThermalCondition(T=363.85, P=101325))

Equilibrium given temperature and pressure:

>>> vle(T=363.88, P=101325)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 127.4), ('Ethanol', 26.41), ('Methanol', 33.54), ('Propanol', 0.8968)],
        l=[('Water', 176.6), ('Ethanol', 3.59), ('Methanol', 6.456), ('Propanol', 0.1032)]),
    thermal_condition=ThermalCondition(T=363.88, P=101325))

Equilibrium given enthalpy and pressure:

>>> H = vle.thermo.mixture.xH(vle.imol, T=363.88, P=101325)
>>> vle(H=H, P=101325)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 127.4), ('Ethanol', 26.41), ('Methanol', 33.54), ('Propanol', 0.8968)],
        l=[('Water', 176.6), ('Ethanol', 3.59), ('Methanol', 6.456), ('Propanol', 0.1032)]),
    thermal_condition=ThermalCondition(T=363.88, P=101325))

Equilibrium given entropy and pressure:

>>> S = vle.thermo.mixture.xS(vle.imol, T=363.88, P=101325)
>>> vle(S=S, P=101325)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 127.4), ('Ethanol', 26.41), ('Methanol', 33.54), ('Propanol', 0.8968)],
        l=[('Water', 176.6), ('Ethanol', 3.59), ('Methanol', 6.456), ('Propanol', 0.1032)]),
    thermal_condition=ThermalCondition(T=363.88, P=101325))

Equilibrium given vapor fraction and temperature:

>>> vle(V=0.5, T=363.88)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 126.7), ('Ethanol', 26.38), ('Methanol', 33.49), ('Propanol', 0.8958)],
        l=[('Water', 177.3), ('Ethanol', 3.622), ('Methanol', 6.509), ('Propanol', 0.1042)]),
    thermal_condition=ThermalCondition(T=363.88, P=101431))

Equilibrium given enthalpy and temperature:

>>> vle(H=H, T=363.88)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 127.4), ('Ethanol', 26.41), ('Methanol', 33.54), ('Propanol', 0.8968)],
        l=[('Water', 176.6), ('Ethanol', 3.59), ('Methanol', 6.456), ('Propanol', 0.1032)]),
    thermal_condition=ThermalCondition(T=363.88, P=101325))

Non-partitioning heavy and gaseous chemicals also affect VLE. Calculation are repeated with non-partitioning chemicals:

>>> from thermosteam import indexer, equilibrium, settings, Chemical
>>> O2 = Chemical('O2', phase='g')
>>> Glucose = Chemical('Glucose', phase='l', default=True)
>>> settings.set_thermo(['Water', 'Ethanol', 'Methanol', 'Propanol', O2, Glucose], cache=True)
>>> imol = indexer.MolarFlowIndexer(
...             l=[('Water', 304), ('Ethanol', 30), ('Glucose', 5)],
...             g=[('Methanol', 40), ('Propanol', 1), ('O2', 10)])
>>> vle = equilibrium.VLE(imol)
>>> vle(T=363.88, P=101325)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 159.5), ('Ethanol', 27.65), ('Methanol', 35.63), ('Propanol', 0.9337), ('O2', 10)],
        l=[('Water', 144.5), ('Ethanol', 2.352), ('Methanol', 4.369), ('Propanol', 0.0663), ('Glucose', 5)]),
    thermal_condition=ThermalCondition(T=363.88, P=101325))

>>> vle(V=0.5, P=101325)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 126.7), ('Ethanol', 26.38), ('Methanol', 33.52), ('Propanol', 0.8957), ('O2', 10)],
        l=[('Water', 177.3), ('Ethanol', 3.618), ('Methanol', 6.478), ('Propanol', 0.1043), ('Glucose', 5)]),
    thermal_condition=ThermalCondition(T=362.47, P=101325))

>>> H = vle.thermo.mixture.xH(vle.imol, T=363.88, P=101325)
>>> vle(H=H, P=101325)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 127.4), ('Ethanol', 26.42), ('Methanol', 33.58), ('Propanol', 0.8968), ('O2', 10)],
        l=[('Water', 176.6), ('Ethanol', 3.583), ('Methanol', 6.421), ('Propanol', 0.1032), ('Glucose', 5)]),
    thermal_condition=ThermalCondition(T=362.51, P=101325))

>>> S = vle.thermo.mixture.xS(vle.imol, T=363.88, P=101325)
>>> vle(S=S, P=101325)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 128.2), ('Ethanol', 26.45), ('Methanol', 33.63), ('Propanol', 0.8979), ('O2', 10)],
        l=[('Water', 175.8), ('Ethanol', 3.548), ('Methanol', 6.365), ('Propanol', 0.1021), ('Glucose', 5)]),
    thermal_condition=ThermalCondition(T=362.54, P=101325))

>>> vle(V=0.5, T=363.88)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 126.7), ('Ethanol', 26.38), ('Methanol', 33.49), ('Propanol', 0.8958), ('O2', 10)],
        l=[('Water', 177.3), ('Ethanol', 3.622), ('Methanol', 6.509), ('Propanol', 0.1042), ('Glucose', 5)]),
    thermal_condition=ThermalCondition(T=363.88, P=106841))

>>> vle(H=H, T=363.88)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 126.7), ('Ethanol', 26.38), ('Methanol', 33.49), ('Propanol', 0.8958), ('O2', 10)],
        l=[('Water', 177.3), ('Ethanol', 3.622), ('Methanol', 6.51), ('Propanol', 0.1042), ('Glucose', 5)]),
    thermal_condition=ThermalCondition(T=363.88, P=106842))

>>> vle(S=S, T=363.88)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 128.1), ('Ethanol', 26.45), ('Methanol', 33.6), ('Propanol', 0.8978), ('O2', 10)],
        l=[('Water', 175.9), ('Ethanol', 3.555), ('Methanol', 6.399), ('Propanol', 0.1022), ('Glucose', 5)]),
    thermal_condition=ThermalCondition(T=363.88, P=106562))

The presence of a non-partitioning gaseous chemical will result in some evaporation, even if the tempeture is below the saturated bubble point:

>>> from thermosteam import indexer, equilibrium, settings, Chemical
>>> O2 = Chemical('O2', phase='g')
>>> settings.set_thermo(['Water', O2], cache=True)
>>> imol = indexer.MolarFlowIndexer(
...             l=[('Water', 30)],
...             g=[('O2', 10)])
>>> vle = equilibrium.VLE(imol)
>>> vle(T=300., P=101325)
>>> vle
VLE(imol=MolarFlowIndexer(
        g=[('Water', 0.3617), ('O2', 10)],
        l=[('Water', 29.64)]),
    thermal_condition=ThermalCondition(T=300.00, P=101325))
__call__(*, T=None, P=None, V=None, H=None, S=None, x=None, y=None)[source]#

Perform vapor-liquid equilibrium.

Parameters:

  • T (float, optional) – Operating temperature [K].

  • P (float, optional) – Operating pressure [Pa].

  • V (float, optional) – Molar vapor fraction.

  • H (float, optional) – Enthalpy [kJ/hr].

  • S (float, optional) – Entropy [kJ/hr/K]

  • x (float, optional) – Molar composition of liquid (for binary mixtures).

  • y (float, optional) – Molar composition of vapor (for binary mixtures).

Notes

You may only specify two of the following parameters: P, H, T, V, x, and y. Additionally, If x or y is specified, the other parameter must be either P or T (e.g., x and V is invalid).

property imol#

[MaterialIndexer] Chemical phase data.

property thermal_condition#

[ThermalCondition] Temperature and pressure data.