# -*- coding: utf-8 -*-
# BioSTEAM: The Biorefinery Simulation and Techno-Economic Analysis Modules
# Copyright (C) 2020-2023, Yoel Cortes-Pena <yoelcortes@gmail.com>
#
# This module is under the UIUC open-source license. See
# github.com/BioSTEAMDevelopmentGroup/biosteam/blob/master/LICENSE.txt
# for license details.
"""
"""
import numpy as np
import flexsolve as flx
from .fugacity_coefficients import IdealFugacityCoefficients
from .domain import vle_domain
from ..exceptions import InfeasibleRegion
from .. import functional as fn
from ..utils import fill_like, Cache
from .._settings import settings
__all__ = (
'BubblePoint', 'BubblePointValues', 'BubblePointCache',
'BubblePointBeta'
)
# %% Solvers
def y_iter(y, y_phi, phi, T, P):
y = fn.normalize(y)
return y_phi / phi(y, T, P)
def solve_y(y_phi, phi, T, P, y_guess):
if isinstance(phi, IdealFugacityCoefficients): return y_phi
return flx.wegstein(y_iter, y_phi, 1e-9, args=(y_phi, phi, T, P),
checkiter=False,
checkconvergence=False,
convergenceiter=3)
# %% Bubble point values container
class BubblePointValues:
__slots__ = ('T', 'P', 'IDs', 'z', 'y')
def __init__(self, T, P, IDs, z, y):
self.T = T
self.P = P
self.IDs = IDs
self.z = z
self.y = y
@property
def x(self): return self.z
def __repr__(self):
return f"{type(self).__name__}(T={self.T:.2f}, P={self.P:.0f}, IDs={self.IDs}, z={self.z}, y={self.y})"
# %% Bubble point calculation
[docs]
class BubblePoint:
"""
Create a BubblePoint object that returns bubble point values when
called with a composition and either a temperture (T) or pressure (P).
Parameters
----------
chemicals=() : Iterable[:class:`~thermosteam.Chemical`], optional
thermo=None : :class:`~thermosteam.Thermo`, optional
Examples
--------
>>> import thermosteam as tmo
>>> chemicals = tmo.Chemicals(['Water', 'Ethanol'], cache=True)
>>> tmo.settings.set_thermo(chemicals)
>>> BP = tmo.equilibrium.BubblePoint(chemicals)
>>> molar_composition = (0.5, 0.5)
>>> # Solve bubble point at constant temperature
>>> bp = BP(z=molar_composition, T=355)
>>> bp
BubblePointValues(T=355.00, P=109407, IDs=('Water', 'Ethanol'), z=[0.5 0.5], y=[0.344 0.656])
>>> # Note that the result is a BubblePointValues object which contain all results as attibutes
>>> (bp.T, round(bp.P), bp.IDs, bp.z, bp.y)
(355, 109407, ('Water', 'Ethanol'), array([0.5, 0.5]), array([0.344, 0.656]))
>>> # Solve bubble point at constant pressure
>>> BP(z=molar_composition, P=101325)
BubblePointValues(T=353.03, P=101325, IDs=('Water', 'Ethanol'), z=[0.5 0.5], y=[0.343 0.657])
"""
__slots__ = ('chemicals', 'IDs', 'gamma', 'phi', 'pcf',
'Psats', 'Tmin', 'Tmax', 'Pmin', 'Pmax')
_cached = {}
T_tol = 1e-9
P_tol = 1e-3
def __init__(self, chemicals=(), thermo=None):
thermo = settings.get_default_thermo(thermo)
chemicals = tuple(chemicals)
key = (chemicals, thermo.Gamma, thermo.Phi, thermo.PCF)
cached = self._cached
if key in cached:
other = cached[key]
fill_like(self, other, self.__slots__)
else:
self.IDs = tuple([i.ID for i in chemicals])
self.gamma = thermo.Gamma(chemicals)
self.phi = thermo.Phi(chemicals)
self.pcf = thermo.PCF(chemicals)
self.Psats = Psats = [i.Psat for i in chemicals]
Tmin, Tmax = vle_domain(chemicals)
self.Tmin = Tmin
self.Tmax = Tmax
self.Pmin = min([i(Tmin) for i in Psats])
self.Pmax = max([i(Tmax) for i in Psats])
self.chemicals = chemicals
cached[key] = self
def _T_error(self, T, P, z_over_P, z_norm, y):
if T <= 0: raise InfeasibleRegion('negative temperature')
Psats = np.array([i(T) for i in self.Psats], dtype=float)
y_phi = (z_over_P
* Psats
* self.gamma(z_norm, T)
* self.pcf(T, P, Psats))
y[:] = solve_y(y_phi, self.phi, T, P, y)
return 1. - y.sum()
def _P_error(self, P, T, z_Psat_gamma, Psats, y):
if P <= 0: raise InfeasibleRegion('negative pressure')
y_phi = z_Psat_gamma * self.pcf(T, P, Psats) / P
y[:] = solve_y(y_phi, self.phi, T, P, y)
return 1. - y.sum()
def _T_error_ideal(self, T, z_over_P, y):
y[:] = z_over_P * np.array([i(T) for i in self.Psats], dtype=float)
return 1 - y.sum()
def _Ty_ideal(self, z_over_P):
f = self._T_error_ideal
y = z_over_P.copy()
args = (z_over_P, y)
Tmin = self.Tmin + 10
Tmax = self.Tmax - 10
fmax = f(Tmin, *args)
if fmax < 0.: return Tmin, y
fmin = f(Tmax, *args)
if fmin > 0.: return Tmax, y
T = flx.IQ_interpolation(f, Tmin, Tmax, fmax, fmin,
None, self.T_tol, 5e-12, args,
checkiter=False,
checkbounds=False)
return T, y
def _Py_ideal(self, z_Psat_gamma_pcf):
P = z_Psat_gamma_pcf.sum()
y = z_Psat_gamma_pcf / P
return P, y
[docs]
def __call__(self, z, *, T=None, P=None):
z = np.asarray(z, float)
if T:
if P: raise ValueError("may specify either T or P, not both")
P, y = self.solve_Py(z, T)
elif P:
T, y = self.solve_Ty(z, P)
else:
raise ValueError("must specify either T or P")
return BubblePointValues(T, P, self.IDs, z, y)
[docs]
def solve_Ty(self, z, P):
"""
Bubble point at given composition and pressure.
Parameters
----------
z : ndarray
Molar composition.
P : float
Pressure [Pa].
Returns
-------
T : float
Bubble point temperature [K].
y : ndarray
Vapor phase molar composition.
Examples
--------
>>> import thermosteam as tmo
>>> import numpy as np
>>> chemicals = tmo.Chemicals(['Water', 'Ethanol'], cache=True)
>>> tmo.settings.set_thermo(chemicals)
>>> BP = tmo.equilibrium.BubblePoint(chemicals)
>>> tmo.docround(BP.solve_Ty(z=np.array([0.6, 0.4]), P=101325))
(353.8284, array([0.383, 0.617]))
"""
positives = z > 0.
N = positives.sum()
if N == 0:
raise ValueError('no components present')
if N == 1:
chemical = self.chemicals[fn.first_true_index(positives)]
T = chemical.Tsat(P, check_validity=False) if P <= chemical.Pc else chemical.Tc
y = z.copy()
else:
f = self._T_error
z_norm = z / z.sum()
z_over_P = z/P
T_guess, y = self._Ty_ideal(z_over_P)
args = (P, z_over_P, z_norm, y)
try:
T = flx.aitken_secant(f, T_guess, T_guess + 1e-3,
self.T_tol, 5e-12, args,
checkiter=False)
except RuntimeError:
Tmin = self.Tmin; Tmax = self.Tmax
T = flx.IQ_interpolation(f, Tmin, Tmax,
f(Tmin, *args), f(Tmax, *args),
T_guess, self.T_tol, 5e-12, args,
checkiter=False, checkbounds=False)
return T, fn.normalize(y)
[docs]
def solve_Py(self, z, T):
"""
Bubble point at given composition and temperature.
Parameters
----------
z : ndarray
Molar composition.
T : float
Temperature [K].
Returns
-------
P : float
Bubble point pressure [Pa].
y : ndarray
Vapor phase molar composition.
Examples
--------
>>> import thermosteam as tmo
>>> import numpy as np
>>> chemicals = tmo.Chemicals(['Water', 'Ethanol'], cache=True)
>>> tmo.settings.set_thermo(chemicals)
>>> BP = tmo.equilibrium.BubblePoint(chemicals)
>>> tmo.docround(BP.solve_Py(z=np.array([0.703, 0.297]), T=352.28))
(91592.781, array([0.42, 0.58]))
"""
positives = z > 0.
N = positives.sum()
if N == 0:
raise ValueError('no components present')
if N == 1:
chemical = self.chemicals[fn.first_true_index(positives)]
P = chemical.Psat(T) if T <= chemical.Tc else chemical.Pc
y = z.copy()
else:
if T > self.Tmax: T = self.Tmax
elif T < self.Tmin: T = self.Tmin
Psat = np.array([i(T) for i in self.Psats])
z_norm = z / z.sum()
z_Psat_gamma = z * Psat * self.gamma(z_norm, T)
f = self._P_error
P_guess, y = self._Py_ideal(z_Psat_gamma)
args = (T, z_Psat_gamma, Psat, y)
try:
P = flx.aitken_secant(f, P_guess, P_guess-1, self.P_tol, 1e-9,
args, checkiter=False)
except RuntimeError:
Pmin = self.Pmin; Pmax = self.Pmax
P = flx.IQ_interpolation(f, Pmin, Pmax,
f(Pmin, *args), f(Pmax, *args),
P_guess, self.P_tol, 5e-12, args,
checkiter=False, checkbounds=False)
return P, fn.normalize(y)
def __repr__(self):
chemicals = ", ".join([i.ID for i in self.chemicals])
return f"{type(self).__name__}([{chemicals}])"
class BubblePointBeta:
"""
Create a BubblePointBeta object that returns bubble point values when
called with a composition and either a temperture (T) or pressure (P).
Parameters
----------
flasher=None : :class:`~thermo.Flash`, optional
Examples
--------
>>> import thermosteam as tmo
>>> chemicals = tmo.Chemicals(['Water', 'Ethanol'], cache=True)
>>> tmo.settings.set_thermo(chemicals)
>>> BP = tmo.equilibrium.BubblePointBeta(chemicals)
>>> molar_composition = (0.5, 0.5)
>>> # Solve bubble point at constant temperature
>>> bp = BP(z=molar_composition, T=355)
>>> # bp
>>> # BubblePointValues(T=355.00, P=111447, IDs=['Water', 'Ethanol'], z=[0.5 0.5], y=[0.341 0.659])
>>> # Note that the result is a BubblePointValues object which contain all results as attibutes
>>> # (bp.T, round(bp.P), bp.IDs, bp.z, bp.y)
>>> # (355, 111447, ['Water', 'Ethanol'], array([0.5, 0.5]), array([0.341, 0.659]))
>>> # Solve bubble point at constant pressure
>>> # BP(z=molar_composition, P=101325)
>>> # BubblePointValues(T=352.59, P=101325, IDs=['Water', 'Ethanol'], z=[0.5 0.5], y=[0.34 0.66])
"""
__slots__ = ('chemicals', 'IDs', 'flasher')
_cached = {}
def __init__(self, chemicals=(), flasher=None):
self.chemicals = chemicals
self.IDs = [i.ID for i in chemicals]
self.flasher = flasher or settings.flasher()
__call__ = BubblePoint.__call__
def solve_Ty(self, z, P):
"""
Bubble point at given composition and pressure.
Parameters
----------
z : ndarray
Molar composition.
P : float
Pressure [Pa].
Returns
-------
T : float
Bubble point temperature [K].
y : ndarray
Vapor phase molar composition.
Examples
--------
>>> import thermosteam as tmo
>>> import numpy as np
>>> chemicals = tmo.Chemicals(['Water', 'Ethanol'], cache=True)
>>> tmo.settings.set_thermo(chemicals)
>>> BP = tmo.equilibrium.BubblePointBeta(chemicals)
>>> # tmo.docround(BP.solve_Ty(z=np.array([0.6, 0.4]), P=101325))
>>> # (353.4052, array([0.38, 0.62]))
"""
positives = z > 0.
N = positives.sum()
if N == 0:
raise ValueError('no components present')
if N == 1:
T = self.chemicals.tuple[fn.first_true_index(positives)].Tsat(P, check_validity=False)
y = z.copy()
else:
results = self.flasher.flash(P=P, VF=0., zs=z.tolist())
y = np.array(results.gas.zs)
T = results.T
return T, fn.normalize(y)
def solve_Py(self, z, T):
"""
Bubble point at given composition and temperature.
Parameters
----------
z : ndarray
Molar composition.
T : float
Temperature [K].
Returns
-------
P : float
Bubble point pressure [Pa].
y : ndarray
Vapor phase molar composition.
Examples
--------
>>> import thermosteam as tmo
>>> import numpy as np
>>> chemicals = tmo.Chemicals(['Water', 'Ethanol'], cache=True)
>>> tmo.settings.set_thermo(chemicals)
>>> BP = tmo.equilibrium.BubblePoint(chemicals)
>>> # tmo.docround(BP.solve_Py(z=np.array([0.703, 0.297]), T=352.28))
>>> # (92966.9114, array([0.418, 0.582]))
"""
positives = z > 0.
N = positives.sum()
if N == 0:
raise ValueError('no components present')
if N == 1:
T = self.chemicals.tuple[fn.first_true_index(positives)].Psat(T)
y = z.copy()
else:
results = self.flasher.flash(T=T, VF=0., zs=z.tolist())
y = np.array(results.gas.zs)
P = results.P
return P, fn.normalize(y)
def __repr__(self):
chemicals = ", ".join([i.ID for i in self.chemicals])
return f"{type(self).__name__}([{chemicals}])"
class BubblePointCache(Cache): load = BubblePoint
del Cache