# -*- 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.
"""
.. contents:: :local:
.. autoclass:: biosteam.units.mixing.Mixer
.. autoclass:: biosteam.units.mixing.SteamMixer
.. autoclass:: biosteam.units.mixing.MockMixer
"""
from .._unit import Unit
from thermosteam._graphics import mixer_graphics
import flexsolve as flx
import biosteam as bst
import numpy as np
from typing import Optional
__all__ = ('Mixer', 'SteamMixer', 'FakeMixer', 'MockMixer')
[docs]
class Mixer(Unit):
"""
Create a mixer that mixes any number of streams together.
Parameters
----------
ins :
Inlet fluids to be mixed.
outs :
Mixed outlet fluid.
rigorous :
Whether to perform vapor-liquid equilibrium.
Notes
-----
When streams at different pressures are mixed, BioSTEAM assumes valves
reduce the pressure of the streams being mixed to prevent backflow
(pressure needs to decrease in the direction of flow according to
Bernoulli's principle). The outlet pressure will be the minimum pressure
of all inlet streams.
Examples
--------
Mix two streams:
>>> from biosteam import units, settings, Stream
>>> settings.set_thermo(['Ethanol', 'Water'], cache=True)
>>> s1 = Stream('s1', Water=20, T=350)
>>> s2 = Stream('s2', Ethanol=30, T=300)
>>> M1 = units.Mixer('M1', ins=(s1, s2), outs='s3')
>>> M1.simulate()
>>> M1.show()
Mixer: M1
ins...
[0] s1
phase: 'l', T: 350 K, P: 101325 Pa
flow (kmol/hr): Water 20
[1] s2
phase: 'l', T: 300 K, P: 101325 Pa
flow (kmol/hr): Ethanol 30
outs...
[0] s3
phase: 'l', T: 315.14 K, P: 101325 Pa
flow (kmol/hr): Ethanol 30
Water 20
"""
_graphics = mixer_graphics
_N_outs = 1
_N_ins = 2
_ins_size_is_fixed = False
def _assert_compatible_property_package(self):
pass # Not necessary for mixing streams
def _init(self, rigorous: Optional[bool]=False,
conserve_phases: Optional[bool]=False):
self.rigorous = rigorous
self.conserve_phases = conserve_phases
def _run(self):
s_out, = self.outs
s_out.mix_from(self.ins, vle=self.rigorous,
conserve_phases=getattr(self, 'conserve_phases', None))
V = s_out.vapor_fraction
if V == 0:
self._B = 0
elif V == 1:
self._B = np.inf
else:
self._B = V / (1 - V)
def _get_energy_departure_coefficient(self, stream):
if stream.phases == ('g', 'l'):
vapor, liquid = stream
if vapor.isempty():
with liquid.temporary_phase('g'): coeff = liquid.H
else:
coeff = -vapor.h * liquid.F_mol
else:
coeff = -stream.C
return (self, coeff)
def _create_energy_departure_equations(self):
# Ll: C1dT1 - Ce2*dT2 - Cr0*dT0 - hv2*L2*dB2 = Q1 - H_out + H_in
# gl: hV1*L1*dB1 - hv2*L2*dB2 - Ce2*dT2 - Cr0*dT0 = Q1 + H_in - H_out
outlet = self.outs[0]
phases = outlet.phases
if phases == ('g', 'l'):
vapor, liquid = outlet
coeff = {}
if vapor.isempty():
with liquid.temporary_phase('g'): coeff[self] = liquid.H
else:
coeff[self] = vapor.h * liquid.F_mol
else:
coeff = {self: outlet.C}
for i in self.ins: i._update_energy_departure_coefficient(coeff)
return [(coeff, self.H_in - self.H_out)]
def _create_material_balance_equations(self, composition_sensitive):
fresh_inlets, process_inlets, equations = self._begin_equations(composition_sensitive)
outlet, = self.outs
if len(outlet) == 1:
ones = np.ones(self.chemicals.size)
minus_ones = -ones
zeros = np.zeros(self.chemicals.size)
# Overall flows
eq_overall = {outlet: ones}
for i in process_inlets: eq_overall[i] = minus_ones
equations.append(
(eq_overall, sum([i.mol for i in fresh_inlets], zeros))
)
else:
top, bottom = outlet
ones = np.ones(self.chemicals.size)
minus_ones = -ones
zeros = np.zeros(self.chemicals.size)
# Overall flows
eq_overall = {}
for i in outlet:
eq_overall[i] = ones
for i in process_inlets:
eq_overall[i] = minus_ones
equations.append(
(eq_overall, sum([i.mol for i in fresh_inlets], zeros))
)
# Top to bottom flows
B = self._B
eq_outs = {}
if B == np.inf:
eq_outs[bottom] = ones
elif B == 0:
eq_outs[top] = ones
else:
bp = outlet.bubble_point_at_P()
outlet.T = bp.T
S = bp.K * B
eq_outs[top] = ones
eq_outs[bottom] = -S
equations.append(
(eq_outs, zeros)
)
return equations
def _update_energy_variable(self, departure):
phases = self.outs[0].phases
if phases == ('g', 'l'):
self._B += departure
else:
self.outs[0].T += departure
def _update_nonlinearities(self): pass
[docs]
class SteamMixer(Unit):
"""
Create a mixer that varies the flow of steam to achieve a specified outlet
pressure and varies the flow of process water to achieve a specified
solids loading (by wt).
Parameters
----------
ins :
* [0] Feed
* [1] Steam
* [2] Process water
outs :
Mixed product.
P : float
Outlet pressure.
T : float
Outlet temperature.
solids_loading : float, optional
Final solids loading after mixing in process water.
soilds_loading_includes_steam : bool, optional
Whether to include steam in solids loading calculation.
Examples
--------
>>> import biosteam as bst
>>> bst.settings.set_thermo(['Water', 'Glucose'])
>>> feed = bst.Stream('feed', Water=10, Glucose=10)
>>> M1 = bst.SteamMixer(None, ins=[feed, 'steam', 'process_water'], outs='outlet', T=431.15, P=557287.5, solids_loading=0.3)
>>> M1.simulate()
>>> M1.show('cwt100') # Note that outlet solids loading is not exactly 0.3 because of the steam requirement.
SteamMixer
ins...
[0] feed
phase: 'l', T: 298.15 K, P: 101325 Pa
composition (%): Water 9.09
Glucose 90.9
------- 1.98e+03 kg/hr
[1] steam
phase: 'g', T: 454.77 K, P: 1.041e+06 Pa
composition (%): Water 100
----- 1.28e+03 kg/hr
[2] process_water
phase: 'l', T: 298.15 K, P: 101325 Pa
composition (%): Water 100
----- 4.02e+03 kg/hr
outs...
[0] outlet
phase: 'l', T: 431.15 K, P: 557288 Pa
composition (%): Water 75.3
Glucose 24.7
------- 7.29e+03 kg/hr
>>> M1.solids_loading_includes_steam = True
>>> M1.simulate()
>>> M1.show('cwt100') # Now the outlet solids content is exactly 0.3
SteamMixer
ins...
[0] feed
phase: 'l', T: 298.15 K, P: 101325 Pa
composition (%): Water 9.09
Glucose 90.9
------- 1.98e+03 kg/hr
[1] steam
phase: 'g', T: 454.77 K, P: 1.041e+06 Pa
composition (%): Water 100
----- 1.02e+03 kg/hr
[2] process_water
phase: 'l', T: 298.15 K, P: 101325 Pa
composition (%): Water 100
----- 3.01e+03 kg/hr
outs...
[0] outlet
phase: 'l', T: 431.15 K, P: 557288 Pa
composition (%): Water 70
Glucose 30
------- 6.01e+03 kg/hr
"""
_N_outs = 1
_N_ins = 3
_ins_size_is_fixed = False
_graphics = mixer_graphics
installation_cost = purchase_cost = 0.
def _init(self, P, T=None, solids_loading=None,
liquid_IDs=['7732-18-5'], solid_IDs=None,
solids_loading_includes_steam=None):
self.P = P
self.T = T
self.solids_loading = solids_loading
self.solids_loading_includes_steam = solids_loading_includes_steam
self.liquid_IDs = tuple(liquid_IDs)
self.solid_IDs = solid_IDs
@property
def steam(self):
return self.ins[1]
def reset_cache(self, isdynamic=None):
for utility in bst.HeatUtility.heating_agents:
if utility.P > self.P: break
self.steam.copy_like(utility)
def pressure_objective_function(self, steam_mol):
mixed = self.outs[0]
self.steam.imol['7732-18-5'] = steam_mol # Only change water
if self.P: mixed.P = self.P # Assume pumps take care of this
if self.solids_loading_includes_steam and self.solids_loading:
solids_loading = self.solids_loading
feed, steam, process_water, *others = self.ins
process_water.empty()
feeds = self.ins
chemicals = self.chemicals
index = chemicals.get_index(self.liquid_IDs)
available_water = 18.01528 * sum([(j.sum() if hasattr((j:=i.mol[index]), 'sum') else j) for i in feeds if i])
solid_IDs = self.solid_IDs
if solid_IDs:
F_mass_solids = sum([i.imass[solid_IDs].sum() for i in feeds if i])
else:
F_mass_feed = sum([i.F_mass for i in feeds if i])
F_mass_solids = F_mass_feed - available_water
required_water = F_mass_solids * (1. - solids_loading) / solids_loading
process_water.imol['7732-18-5'] = max(required_water - available_water, 0.) / 18.01528
mixed.mix_from(self.ins, energy_balance=False)
H = sum([i.H for i in self.ins])
Tmax = mixed.chemicals.Water.Tc - 1
mixed.T = Tmax
Hmax = mixed.H
if H > Hmax:
mixed.T = Tmax + (H - Hmax) / mixed.chemicals.Water.Cn('l', Tmax)
else:
mixed.H = H
if self.T:
return self.T - mixed.T
else: # If no pressure, assume it is at the boiling point
P_new = mixed.chemicals.Water.Psat(min(mixed.T, Tmax))
return self.P - P_new
def _setup(self):
super()._setup()
if self.steam.isempty(): self.reset_cache()
def _run(self):
solids_loading = self.solids_loading
if solids_loading is not None and not self.solids_loading_includes_steam:
# Solids loading need to be achieved first before mixing with steam
# to avoid pumping issues (see Humbird 2011 NREL report).
feed, steam, process_water, *others = self.ins
process_water.empty()
feeds = [feed, *others]
chemicals = self.chemicals
index = chemicals.get_index(self.liquid_IDs)
available_water = 18.01528 * sum([(j.sum() if hasattr((j:=i.mol[index]), 'sum') else j) for i in feeds if i])
solid_IDs = self.solid_IDs
if solid_IDs:
F_mass_solids = sum([i.imass[solid_IDs].sum() for i in feeds if i])
else:
F_mass_feed = sum([i.F_mass for i in feeds if i])
F_mass_solids = F_mass_feed - available_water
required_water = F_mass_solids * (1. - solids_loading) / solids_loading
process_water.imol['7732-18-5'] = max(required_water - available_water, 0.) / 18.01528
else:
steam = self.steam
steam_mol = steam.F_mol or 1.
f = self.pressure_objective_function
steam_mol = flx.IQ_interpolation(f, *flx.find_bracket(f, 0., steam_mol, None, None),
xtol=1e-2, ytol=1e-4,
maxiter=500, checkroot=False)
self.outs[0].P = self.P
def _design(self):
steam = self.ins[1]
warm_process_water = self.ins[2]
mixed = self.outs[0]
self.add_heat_utility(steam.H + warm_process_water.H, mixed.T)
[docs]
class MockMixer(Unit):
"""
Create a MockMixer object that does nothing when simulated.
"""
_graphics = Mixer._graphics
_N_ins = 2
_N_outs = 1
_ins_size_is_fixed = False
def _run(self): pass
MockMixer.line = 'Mixer'
FakeMixer = MockMixer
