# -*- 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 biosteam as bst
from .. import Unit
from .mixing import Mixer
from .heat_exchange import HXutility
from ._flash import Flash, Evaporator
from .design_tools import (
compute_vacuum_system_power_and_cost,
compute_heat_transfer_area
)
from thermosteam import MultiStream, settings
import flexsolve as flx
from warnings import warn
import numpy as np
from .design_tools import heat_transfer as ht
__all__ = ('MultiEffectEvaporator',)
log = np.log
exp = np.exp
# Table 22.32 Product process and design (pg 592)
# Name: ('Area range (m2)', 'Cost(A) (USD)', 'U (kJ/(hr*m2*K)))', 'Material')
evaporators = {'Horizontal tube':
((9.29, 743.224),
lambda A, CE: CE*2.304*A**0.53,
4906.02,
'Carbon steel'),
'Long-tube vertical':
((9.29, 743.224),
lambda A, CE: CE*3.086*A**0.55,
8176.699,
'Carbon steel'),
'Forced circulation':
((13.935, 8000),
lambda A, CE: CE/500*exp(8.2986 + 0.5329*log(A*0.0929)-0.000196*log(A*0.0929)**2),
10731.918,
'Carbon steel'),
'Falling film':
((13.935, 371.612),
lambda A, CE: CE*7.416*A**0.55,
10220.874,
'Stainless steel tubes/Carbon steel shell')}
[docs]
class MultiEffectEvaporator(Unit):
"""
Creates evaporatorators with pressures given by P (a list of pressures).
Adjusts first evaporator vapor fraction to satisfy an overall fraction
evaporated. All evaporators after the first have zero duty. Condenses
the vapor coming out of the last evaporator. Pumps all liquid streams
to prevent back flow in later parts. All liquid evaporated is ultimately
recondensed. Cost is based on required heat transfer area. Vacuum system
is based on air leakage. Air leakage is based on volume, as given by
residence time `tau` and flow rate to each evaporator.
Parameters
----------
ins :
Inlet.
outs :
* [0] Solid-rich stream.
* [1] Condensate stream.
P : tuple[float]
Pressures describing each evaporator (Pa).
V : float
Molar fraction evaporated as specified in `V_definition`
(either overall or in the first effect).
V_definition : str, optional
* 'Overall' - `V` is the overall molar fraction evaporated.
* 'First-effect' - `V` is the molar fraction evaporated in the first effect.
Examples
--------
Concentrate sugar setting vapor fraction at the first effect:
>>> import biosteam as bst
>>> bst.process_tools.default()
>>> from biorefineries.cellulosic import create_cellulosic_ethanol_chemicals
>>> bst.settings.set_thermo(create_cellulosic_ethanol_chemicals())
>>> feed = bst.Stream('feed', Water=1000, Glucose=100,
... AceticAcid=0.5, HMF=0.1, Furfural=0.1,
... units='kg/hr')
>>> E1 = bst.MultiEffectEvaporator('E1', ins=feed, outs=('solids', 'liquid'),
... V=0.1, V_definition='First-effect',
... P=(101325, 73581, 50892, 32777, 20000))
>>> E1.simulate()
>>> E1.show()
MultiEffectEvaporator: E1
ins...
[0] feed
phase: 'l', T: 298.15 K, P: 101325 Pa
flow (kmol/hr): Water 55.5
AceticAcid 0.00833
Furfural 0.00104
HMF 0.000793
Glucose 0.555
outs...
[0] solids
phase: 'l', T: 333.21 K, P: 20000 Pa
flow (kmol/hr): Water 20.5
AceticAcid 0.00183
Furfural 5.96e-05
HMF 0.000793
Glucose 0.555
[1] liquid
phase: 'l', T: 352.11 K, P: 20000 Pa
flow (kmol/hr): Water 35
AceticAcid 0.0065
Furfural 0.000981
>>> E1.results()
Multi-effect evaporator Units E1
Electricity Power kW 5.72
Cost USD/hr 0.447
Low pressure steam Duty kJ/hr 5.83e+05
Flow kmol/hr 15.1
Cost USD/hr 3.58
Cooling water Duty kJ/hr -3.5e+05
Flow kmol/hr 239
Cost USD/hr 0.117
Design Area m^2 11
Volume m^3 3.51
Purchase cost Evaporators (x5) USD 9.56e+03
Condenser - Double pipe USD 5.36e+03
Vacuum system - Liquid-ring pump... USD 1.07e+04
Total purchase cost USD 2.56e+04
Utility cost USD/hr 4.15
Concentrate sugar setting overall vapor fraction:
>>> import biosteam as bst
>>> from biorefineries.cellulosic import create_cellulosic_ethanol_chemicals
>>> bst.settings.set_thermo(create_cellulosic_ethanol_chemicals())
>>> feed = bst.Stream('feed', Water=1000, Glucose=100,
... AceticAcid=0.5, HMF=0.1, Furfural=0.1,
... units='kg/hr')
>>> E1 = bst.MultiEffectEvaporator('E1', ins=feed, outs=('solids', 'liquid'),
... V=0.1, V_definition='Overall',
... P=(101325, 73581, 50892, 32777, 20000))
>>> E1.simulate()
>>> E1.show()
MultiEffectEvaporator: E1
ins...
[0] feed
phase: 'l', T: 298.15 K, P: 101325 Pa
flow (kmol/hr): Water 55.5
AceticAcid 0.00833
Furfural 0.00104
HMF 0.000793
Glucose 0.555
outs...
[0] solids
phase: 'l', T: 354.91 K, P: 50892 Pa
flow (kmol/hr): Water 50
AceticAcid 0.00683
Furfural 0.000535
HMF 0.000793
Glucose 0.555
[1] liquid
phase: 'l', T: 361.13 K, P: 50892 Pa
flow (kmol/hr): Water 5.55
AceticAcid 0.0015
Furfural 0.000506
>>> E1.results()
Multi-effect evaporator Units E1
Electricity Power kW 5.72
Cost USD/hr 0.447
Low pressure steam Duty kJ/hr 3.84e+05
Flow kmol/hr 9.94
Cost USD/hr 2.36
Cooling water Duty kJ/hr -1.15e+05
Flow kmol/hr 78.8
Cost USD/hr 0.0384
Design Area m^2 1.62
Volume m^3 3.07
Purchase cost Evaporators (x3) USD 2.74e+03
Condenser - Double pipe USD 3.9e+03
Vacuum system - Liquid-ring pump... USD 1.08e+04
Total purchase cost USD 1.74e+04
Utility cost USD/hr 2.85
Concentrate sugar setting overall vapor fraction:
>>> import biosteam as bst
>>> from biorefineries.cellulosic import create_cellulosic_ethanol_chemicals
>>> bst.settings.set_thermo(create_cellulosic_ethanol_chemicals())
>>> feed = bst.Stream('feed', Water=1000, Glucose=100,
... AceticAcid=0.5, HMF=0.1, Furfural=0.1,
... units='kg/hr')
>>> E1 = bst.MultiEffectEvaporator('E1', ins=feed, outs=('solids', 'liquid'),
... V=0.1, V_definition='Overall',
... P=(101325, 73581, 50892, 32777, 20000))
>>> E1.simulate()
>>> E1.show()
MultiEffectEvaporator: E1
ins...
[0] feed
phase: 'l', T: 298.15 K, P: 101325 Pa
flow (kmol/hr): Water 55.5
AceticAcid 0.00833
Furfural 0.00104
HMF 0.000793
Glucose 0.555
outs...
[0] solids
phase: 'l', T: 354.91 K, P: 50892 Pa
flow (kmol/hr): Water 50
AceticAcid 0.00683
Furfural 0.000535
HMF 0.000793
Glucose 0.555
[1] liquid
phase: 'l', T: 361.13 K, P: 50892 Pa
flow (kmol/hr): Water 5.55
AceticAcid 0.0015
Furfural 0.000506
>>> E1.results()
Multi-effect evaporator Units E1
Electricity Power kW 5.72
Cost USD/hr 0.447
Low pressure steam Duty kJ/hr 3.84e+05
Flow kmol/hr 9.94
Cost USD/hr 2.36
Cooling water Duty kJ/hr -1.15e+05
Flow kmol/hr 78.8
Cost USD/hr 0.0384
Design Area m^2 1.62
Volume m^3 3.07
Purchase cost Evaporators (x3) USD 2.74e+03
Condenser - Double pipe USD 3.9e+03
Vacuum system - Liquid-ring pump... USD 1.08e+04
Total purchase cost USD 1.74e+04
Utility cost USD/hr 2.85
"""
line = 'Multi-effect evaporator'
vacuum_system_preference = 'Liquid-ring pump'
auxiliary_unit_names = ('condenser', 'mixer', 'vacuum_system', 'evaporators')
_units = {'Area': 'm^2',
'Volume': 'm^3'}
_F_BM_default = {'Evaporators': 2.45,
'Vacuum system': 1.0,
'Condenser': 3.17}
_N_outs = 2
# Evaporator type
_Type = 'Forced circulation'
# Data for simmulation and costing
_evap_data = evaporators[_Type]
@property
def Type(self):
"""Evaporation type."""
return self._Type
@Type.setter
def Type(self, evap_type):
try:
self._evap_data = evaporators[evap_type]
except KeyError:
dummy = str(evaporators.keys())[11:-2]
raise ValueError(f"Type must be one of the following: {dummy}")
self._Type = evap_type
@property
def V_definition(self):
"""[str] Must be one of the following:
* 'Overall' - Defines attribute `V` as the overall molar fraction evaporated.
* 'First-effect' - Defines attribute `V` as the molar fraction evaporated in the first effect.
* 'First-effect duty' - Defines attribute `V` as the supplied duty over the total duty required to achived a vapor fraction of 1 at the first effect .
"""
return self._V_definition
@V_definition.setter
def V_definition(self, V_definition):
V_definition = V_definition.capitalize()
if V_definition in ('Overall', 'First-effect', 'First-effect duty'):
self._reload_components = True
self._V_definition = V_definition
else:
raise ValueError("V_definition must be either 'Overall', 'First-effect', or 'First-effect duty'")
def _init(self, P, V, V_definition='Overall',
flash=True, chemical='7732-18-5'):
self.P = P #: tuple[float] Pressures describing each evaporator (Pa).
self.V = V #: [float] Molar fraction evaporated.
self.V_definition = V_definition
self.flash = flash #: [bool] Whether to perform a flash calculation to account for volatile components.
self._V_first_effect = None
self.chemical = chemical
def reset_cache(self, isdynamic=None):
self._reload_components = True
def _load_components(self):
P = self.P
self._N_evap = n = len(P) # Number of evaporators
self.evaporators = []
if self.flash:
evaporator = self.auxiliary(
'evaporators', Flash,
ins=self.ins,
outs=(None, self.outs[0] if n == 1 else None), P=P[0],
)
else:
evaporator = self.auxiliary(
'evaporators', Evaporator,
ins=self.ins,
outs=(None, self.outs[0] if n == 1 else None), P=P[0],
chemical=self.chemical,
)
for i in range(1, n):
evaporator = self.auxiliary(
'evaporators', Evaporator,
# Put liquid first, then vapor side stream
ins=(evaporator.outs[1], evaporator.outs[0]),
outs=(None, self.outs[0] if i == n-1 else None, None),
P=P[i], chemical=self.chemical,
)
condenser = self.auxiliary(
'condenser', HXutility, ins=evaporator.outs[0], outs=[None], V=0
)
self.auxiliary(
'mixer', Mixer,
ins=[condenser.outs[0], *[i.outs[2] for i in self.evaporators[1:]]],
outs=self.outs[1]
)
def _V_overall(self, V_first_effect):
first_evaporator, *other_evaporators = self.evaporators
V_definition = self.V_definition
chemical = self.chemical
feed = first_evaporator.ins[0]
if V_definition in ('First-effect', 'Overall'):
first_evaporator.V = V_overall = V_first_effect
elif V_definition == 'First-effect duty':
if isinstance(first_evaporator, Flash):
stream = feed.copy()
stream.vle(P=first_evaporator.P, V=1)
Hvap = stream.H - feed.H
Q = V_first_effect * Hvap
else:
Hvap = first_evaporator.Hvap * first_evaporator.ins[0].imol[chemical]
Q = V_first_effect * Hvap
first_evaporator.Q = Q
first_evaporator._run()
for evap in other_evaporators: evap._run()
evaporated = self.evaporators[-1].outs[1]
V_overall = 1. - evaporated.imol[chemical] / feed.imol[chemical]
return V_overall
def _V_overall_objective_function(self, V_first_effect):
return self._V_overall(V_first_effect) - self.V
def _run(self):
out_wt_solids, liq = self.outs
ins = self.ins
if self.V == 0:
out_wt_solids.copy_like(ins[0])
liq.empty()
self._reload_components = True
return
if self._reload_components:
self._load_components()
self._reload_components = False
if self.V_definition == 'Overall':
P = tuple(self.P)
self.P = list(P)
for i in range(self._N_evap - 1):
if self._V_overall(0.) > self.V:
self.P.pop()
self._load_components()
self._reload_components = True
else:
break
self.P = P
self._V_first_effect = flx.IQ_interpolation(self._V_overall_objective_function,
0., 1., None, None, self._V_first_effect,
xtol=1e-9, ytol=1e-6,
checkiter=False)
V_overall = self.V
else:
V_overall = self._V_overall(self.V)
evaporators = self.evaporators
condenser = self.condenser
mixer = self.mixer
last_evaporator = evaporators[-1]
# Condense vapor from last effector
condenser._run()
# Mix liquid streams
liq = mixer.outs[0]
liq.P = self.ins[0].P
liq.mix_from(mixer.ins, conserve_phases=True)
if self.flash:
mixed_stream = MultiStream(None, thermo=self.thermo)
mixed_stream.copy_flow(self.ins[0])
mixed_stream.vle(P=last_evaporator.P, V=V_overall)
out_wt_solids.mol = mixed_stream.imol['l']
if liq.phase == 'l':
liq.phase = 'l'
liq.mol = mixed_stream.imol['g']
else:
H = liq.H
liq.copy_like(mixed_stream['g'])
liq.vle(H=H, P=self.ins[0].P)
liq.P = out_wt_solids.P
def _design(self):
if self.V == 0:
for i in self.auxiliary_units: i._setup()
return
# This functions also finds the cost
A_range, C_func, U, _ = self._evap_data
evaporators = self.evaporators
Design = self.design_results
Cost = self.baseline_purchase_costs
CE = bst.CE
first_evaporator = evaporators[0]
if self.flash:
duty = first_evaporator.H_out - first_evaporator.H_in
else:
duty = first_evaporator.design_results['Heat transfer']
# Cost first evaporators
Q = abs(duty)
Tci = first_evaporator.ins[0].T
Tco = first_evaporator.outs[0].T
hu = self.create_heat_utility()
hu(duty, Tci, Tco)
Th = hu.inlet_utility_stream.T
LMTD = ht.compute_LMTD(Th, Th, Tci, Tco)
ft = 1
A = abs(compute_heat_transfer_area(LMTD, U, Q, ft))
self._evap_costs = evap_costs = [C_func(A, CE)]
# Find condenser requirements
condenser = self.condenser
condenser.simulate(run=False)
# Find area and cost of evaporators
As = [A]
evap = evaporators[-1]
bounds_warning = bst.exceptions.bounds_warning
for evap in evaporators[1:]:
Q = evap.design_results['Heat transfer']
if Q <= 1e-12:
As.append(0.)
evap_costs.append(0.)
else:
Tc = evap.outs[0].T
Th = evap.outs[2].T
LMTD = Th - Tc
A = compute_heat_transfer_area(LMTD, U, Q, 1.)
As.append(A)
bounds_warning(self, 'heat transfer area requirement', A, 'ft2', A_range, 'cost')
evap_costs.append(C_func(A, CE))
self._As = As
Design['Area'] = A = sum(As)
total_volume = 0
for evap in evaporators:
if evap.outs[0].isempty(): continue
evap._size_flash_vessel()
vapor_sep_design = evap.design_results
L = vapor_sep_design['Length']
D = vapor_sep_design['Diameter']
R = D / 2.
total_volume += 0.0283168466 * np.pi * L * R * R # m3
Design['Volume'] = total_volume
Cost['Evaporators'] = sum(evap_costs)
self.vacuum_system = bst.VacuumSystem(
self, self.vacuum_system_preference, vessel_volume=total_volume, P_suction=self.outs[0].P,
)