Flash#

class Flash(ID='', ins=None, outs=(), thermo=None, **kwargs)[source]#

Create an equlibrium based flash drum with the option of having light non-keys and heavy non-keys completly separate into their respective phases. Design procedure is based on heuristics by Wayne D. Monnery & William Y. Svrcek [1]. Purchase costs are based on correlations by Mulet et al. [2] [3] as compiled by Warren et. al. [4].

Parameters:

  • ins (Sequence[Stream | str], optional) – Inlet fluid.

  • outs (Sequence[Stream | str], optional) –

    • [0] Vapor product

    • [1] Liquid product

  • P=None (float) – Operating pressure [Pa].

  • Q=None (float) – Duty [kJ/hr].

  • T=None (float) – Operating temperature [K].

  • V=None (float) – Molar vapor fraction.

  • x=None (float) – Molar composition of liquid (for binary mixtures).

  • y=None (float) – Molar composition of vapor (for binary mixtures).

  • vessel_material (str, optional) – Vessel construction material. Defaults to ‘Carbon steel’.

  • vacuum_system_preference ('Liquid-ring pump', 'Steam-jet ejector', or 'Dry-vacuum pump') – If a vacuum system is needed, it will choose one according to this preference. Defaults to ‘Liquid-ring pump’.

  • has_glycol_groups=False (bool) – True if glycol groups are present in the mixture.

  • has_amine_groups=False (bool) – True if amine groups are present in the mixture.

  • vessel_type=None ('Horizontal' or 'Vertical', optional) – Vessel separation type. If not specified, the vessel type will be chosen according to heuristics.

  • holdup_time=15.0 (float) – Time it takes to raise liquid to half full [min].

  • surge_time=7.5 (float) – Time it takes to reach from normal to maximum liquied level [min].

  • has_mist_eliminator (bool) – True if using a mist eliminator pad.

Notes

You may only specify two of the following parameters: P, Q, 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).

Examples

>>> from biosteam.units import Flash
>>> from biosteam import Stream, settings
>>> settings.set_thermo(['Water', 'Glycerol'], cache=True)
>>> feed = Stream('feed', Glycerol=300, Water=1000)
>>> bp = feed.bubble_point_at_P() # Feed at bubble point T
>>> feed.T = bp.T
>>> F1 = Flash('F1',
...            ins=feed,
...            outs=('vapor', 'crude_glycerin'),
...            P=101325, # Pa
...            T=410.15) # K
>>> F1.simulate()
>>> F1.show(T='degC', P='atm')
Flash: F1
ins...
[0] feed
    phase: 'l', T: 100.67 degC, P: 1 atm
    flow (kmol/hr): Water     1e+03
                    Glycerol  300
outs...
[0] vapor
    phase: 'g', T: 137 degC, P: 1 atm
    flow (kmol/hr): Water     958
                    Glycerol  2.32
[1] crude_glycerin
    phase: 'l', T: 137 degC, P: 1 atm
    flow (kmol/hr): Water     42.4
                    Glycerol  298
>>> F1.results()
Flash                                                   Units            F1
Medium pressure steam Duty                              kJ/hr      4.81e+07
                      Flow                            kmol/hr      1.33e+03
                      Cost                             USD/hr           366
Design                Vessel type                                Horizontal
                      Length                               ft          8.46
                      Diameter                             ft           5.5
                      Weight                               lb      2.51e+03
                      Wall thickness                       in         0.312
                      Vessel material                          Carbon steel
Purchase cost         Horizontal pressure vessel          USD      1.47e+04
                      Platform and ladders                USD      3.22e+03
                      Heat exchanger - Floating head      USD      4.48e+04
Total purchase cost                                       USD      6.26e+04
Utility cost                                           USD/hr           366

References

auxiliary_unit_names: tuple[str, ...] = ('heat_exchanger', 'vacuum_system', 'vapor_condenser')#

Auxiliary unit operation names.

property P#

Operating pressure (Pa).

property vapor#

Outlet vapor stream (equivalent to outs[0]).

property liquid#

Outlet liquid stream (equivalent to outs[1]).

line: str = 'Flash'#

class-attribute Name denoting the type of Unit class. Defaults to the class name of the first child class

run()#

Run mass and energy balance. This method also runs specifications user defined specifications unless it is being run within a specification (to avoid infinite loops).

See also

_run, specifications, add_specification, add_bounded_numerical_specification

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