# -*- 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.stirred_tank_reactor.StirredTankReactor
References
----------
.. [1] Seider, W. D.; Lewin, D. R.; Seader, J. D.; Widagdo, S.; Gani, R.;
Ng, M. K. Product and Process Design Principles. Wiley 2017.
"""
from .. import Unit
from typing import Optional
from math import ceil
from biosteam.units.design_tools.geometry import cylinder_diameter_from_volume
import biosteam as bst
from biosteam.units.design_tools import (
PressureVessel, compute_closed_vessel_turbine_purchase_cost, size_batch
)
__all__ = (
'StirredTankReactor', 'STR',
'ContinuousStirredTankReactor', 'CSTR',
)
[docs]
class StirredTankReactor(PressureVessel, Unit, isabstract=True):
'''
Abstract class for a stirred tank reactor, modeled as a pressure vessel with
a given aspect ratio and residence time. A pump-heat exchanger recirculation
loop is used to satisfy the duty, if any. By default, a turbine agitator is
also included if the power usage,`kW_per_m3` , is positive. A vacuum
system is also automatically added if the operating pressure is at a vacuum.
Parameters
----------
tau :
Residence time [hr].
T :
Operating temperature [K].
P :
Operating pressure [Pa].
dT_hx_loop :
Maximum change in temperature for the heat exchanger loop. Defaults to 5 K.
V_wf :
Fraction of working volume over total volume. Defaults to 0.8.
V_max :
Maximum volume of a reactor [m3]. Defaults to 355.
kW_per_m3:
Power usage of agitator. Defaults to 0.985 [kW / m3] converted from
5 hp/1000 gal as in [1]_, for liquid–liquid reaction or extraction.
vessel_material :
Vessel material. Defaults to 'Stainless steel 316'.
vessel_type :
Vessel type. Valid options are 'Horizontal' or 'Vertical'. Defaults to 'Vertical'
batch :
Whether to use batch operation mode. If False, operation mode is continuous.
Defaults to `continuous`.
tau_0 :
Cleaning and unloading time (if batch mode). Defaults to 3 hr.
Notes
-----
The recirculation loop takes into account the required flow rate needed to
reach the maximum temperature change of the heat exchanger, `dT_hx_loop`.
Increasing `dT_hx_loop` decreases the required recirculation flow rate and
therefore decreases pump costs.
When parallel reactors are required, one recirculation loop (each with a
pump and heat exchanger) is assumed. Although it is possible to use the
same recirculation loop for all reactors, this conservative assumption allows
for each reactor to be operated independently from each other.
The capital cost for agitators are not yet included in
Examples
--------
Inherit from StirredTankReactor to create a new class that
simulates the continuous fermentative production of ethanol from sugarcane
juice:
>>> import biosteam as bst
>>> class ContinuousFermentation(bst.CSTR):
... _N_ins = 1
... _N_outs = 2
... T_default = 32. + 273.15
... P_default = 101325.
... tau_default = 8.
...
... def _setup(self):
... super()._setup()
... chemicals = self.chemicals
... self.hydrolysis_reaction = bst.Reaction('Sucrose + Water -> 2Glucose', 'Sucrose', 1.00, chemicals)
... self.fermentation_reaction = bst.Reaction('Glucose -> 2Ethanol + 2CO2', 'Glucose', 0.9, chemicals)
... self.cell_growth_reaction = cell_growth = bst.Reaction('Glucose -> Yeast', 'Glucose', 0.70, chemicals, basis='wt')
...
... def _run(self):
... vent, effluent = self.outs
... effluent.mix_from(self.ins, energy_balance=False)
... self.hydrolysis_reaction(effluent)
... self.fermentation_reaction(effluent)
... self.cell_growth_reaction(effluent)
... effluent.T = vent.T = self.T
... effluent.P = vent.P = self.P
... vent.phase = 'g'
... vent.empty()
... vent.receive_vent(effluent, energy_balance=False)
...
>>> from biorefineries.sugarcane import chemicals
>>> bst.settings.set_thermo(chemicals)
>>> feed = bst.Stream('feed',
... Water=1.20e+05,
... Glucose=1.89e+03,
... Sucrose=2.14e+04,
... DryYeast=1.03e+04,
... units='kg/hr',
... T=32+273.15)
>>> R1 = ContinuousFermentation('R1', ins=feed, outs=('CO2', 'product'))
>>> R1.simulate()
>>> R1.show()
ContinuousFermentation: R1
ins...
[0] feed
phase: 'l', T: 305.15 K, P: 101325 Pa
flow (kmol/hr): Water 6.66e+03
Glucose 10.5
Sucrose 62.5
Yeast 456
outs...
[0] CO2
phase: 'g', T: 305.15 K, P: 101325 Pa
flow (kmol/hr): Water 9.95
Ethanol 3.71
CO2 244
[1] product
phase: 'l', T: 305.15 K, P: 101325 Pa
flow (kmol/hr): Water 6.59e+03
Ethanol 240
Glucose 4.07
Yeast 532
>>> R1.results()
Continuous fermentation Units R1
Electricity Power kW 1.04e+03
Cost USD/hr 81.5
Chilled water Duty kJ/hr -1.41e+07
Flow kmol/hr 9.42e+03
Cost USD/hr 70.3
Design Reactor volume m3 319
Residence time hr 8
Vessel type Vertical
Length ft 50.5
Diameter ft 16.8
Weight lb 5.39e+04
Wall thickness in 0.363
Vessel material Stainless steel 316
Purchase cost Vertical pressure vessel (x4) USD 1.18e+06
Platform and ladders (x4) USD 2.12e+05
Heat exchanger - Floating head (x4) USD 1.61e+05
Recirculation pump - Pump (x4) USD 3.9e+04
Recirculation pump - Motor (x4) USD 2.78e+03
Agitator - Agitator (x4) USD 4.53e+05
Total purchase cost USD 2.05e+06
Utility cost USD/hr 152
'''
auxiliary_unit_names = (
'heat_exchanger',
'vacuum_system',
'recirculation_pump',
'splitter',
'agitator',
'scaler',
)
_units = {**PressureVessel._units,
'Batch time': 'hr',
'Loading time': 'hr',
'Residence time': 'hr',
'Total volume': 'm3',
'Reactor volume': 'm3'}
#: Default operating temperature [K]
T_default: Optional[float] = None
#: Default operating pressure [K]
P_default: Optional[float] = None
#: Default residence time [hr]
tau_default: Optional[float] = None
#: Default maximum change in temperature for the heat exchanger loop.
dT_hx_loop_default: Optional[float] = 5
#: Default fraction of working volume over total volume.
V_wf_default: Optional[float] = 0.8
#: Default maximum volume of a reactor in m3.
V_max_default: Optional[float] = 355
#: Default length to diameter ratio.
length_to_diameter_default: Optional[float] = 3
#: Default power consumption for agitation [kW/m3].
kW_per_m3_default: Optional[float] = 0.985
#: Default cleaning and unloading time (hr).
tau_0_default: Optional[float] = 3
#: Whether to default operation in batch mode or continuous
batch_default = False
@property
def effluent(self):
return self.outs[-1]
product = effluent
def _init(
self,
T: Optional[float]=None,
P: Optional[float]=None,
dT_hx_loop: Optional[float]=None,
tau: Optional[float]=None,
V_wf: Optional[float]=None,
V_max: Optional[float]=None,
length_to_diameter: Optional[float]=None,
kW_per_m3: Optional[float]=None,
vessel_material: Optional[str]=None,
vessel_type: Optional[str]=None,
batch: Optional[bool]=None,
tau_0: Optional[float]=None,
adiabatic: Optional[bool]=None,
):
if adiabatic is None: adiabatic = False
self.T = self.T_default if (T is None and not adiabatic) else T
self.adiabatic = adiabatic
self.P = self.P_default if P is None else P
self.dT_hx_loop = self.dT_hx_loop_default if dT_hx_loop is None else abs(dT_hx_loop)
self.tau = self.tau_default if tau is None else tau
self.V_wf = self.V_wf_default if V_wf is None else V_wf
self.V_max = self.V_max_default if V_max is None else V_max
self.length_to_diameter = self.length_to_diameter_default if length_to_diameter is None else length_to_diameter
self.kW_per_m3 = self.kW_per_m3_default if kW_per_m3 is None else kW_per_m3
self.vessel_material = 'Stainless steel 316' if vessel_material is None else vessel_material
self.vessel_type = 'Vertical' if vessel_type is None else vessel_type
self.tau_0 = self.tau_0_default if tau_0 is None else tau_0
self.batch = self.batch_default if batch is None else batch
self.load_auxiliaries()
def load_auxiliaries(self):
if self.adiabatic: return
pump = self.auxiliary('recirculation_pump', bst.Pump)
if self.batch:
self.auxiliary('heat_exchanger', bst.HXutility, pump-0)
else:
# Split is updated later
splitter = self.auxiliary('splitter', bst.Splitter, pump-0, split=0.5)
self.auxiliary('heat_exchanger', bst.HXutility, splitter-0)
self.auxiliary('scaler', bst.Scaler, splitter-1, self.outs[-1])
def _get_duty(self):
return self.Hnet
def _design(self):
Design = self.design_results
ins_F_vol = sum([i.F_vol for i in self.ins if i.phase != 'g'])
P_pascal = (self.P if self.P else self.outs[0].P)
P_psi = P_pascal * 0.000145038 # Pa to psi
length_to_diameter = self.length_to_diameter
if self.batch:
v_0 = ins_F_vol
tau = self.tau
tau_0 = self.tau_0
V_wf = self.V_wf
Design = self.design_results
V_max = self.V_max
N = v_0 / V_max / V_wf * (tau + tau_0) + 1
if N < 2:
N = 2
else:
N = ceil(N)
Design.update(size_batch(v_0, tau, tau_0, N, V_wf))
V_reactor = Design['Reactor volume']
else:
V_total = ins_F_vol * self.tau / self.V_wf
N = ceil(V_total/self.V_max)
if N == 0:
V_reactor = 0
else:
V_reactor = V_total / N
Design['Reactor volume'] = V_reactor
D = cylinder_diameter_from_volume(V_reactor, self.length_to_diameter)
D *= 3.28084 # Convert from m to ft
L = D * length_to_diameter
Design['Residence time'] = self.tau
Design.update(self._vessel_design(float(P_psi), float(D), float(L)))
self.vacuum_system = bst.VacuumSystem(self) if P_pascal < 1e5 else None
self.parallel['self'] = N
self.parallel['vacuum_system'] = 1 # Not in parallel
if self.adiabatic: return
duty = self._get_duty()
if duty:
# Note: Flow and duty are rescaled to simulate an individual
# heat exchanger, then BioSTEAM accounts for number of units in parallel
# through the `parallel` attribute.
if N == 0:
raise RuntimeError(
'stirred tank reactor has heating/cooling duty but no '
'liquid to recirculate to heat exchanger'
)
reactor_duty = duty / N
dT_hx_loop = self.dT_hx_loop
reactor_product = self.effluent.copy()
reactor_product.scale(1 / N)
hx_inlet = reactor_product.copy()
hx_outlet = hx_inlet.copy()
hx_outlet.T += (dT_hx_loop if duty > 0. else -dT_hx_loop)
dH = hx_outlet.H - hx_inlet.H
recirculation_ratio = reactor_duty / dH # Recirculated flow over net product flow
hx_inlet.scale(recirculation_ratio)
hx_outlet.scale(recirculation_ratio)
if self.batch:
self.recirculation_pump.ins[0].copy_like(hx_inlet)
self.recirculation_pump.simulate()
else:
self.recirculation_pump.ins[0].mix_from([hx_inlet, reactor_product])
self.recirculation_pump.simulate()
self.splitter.split = recirculation_ratio / (1 + recirculation_ratio)
self.splitter.simulate()
self.scaler.scale = N
self.scaler.simulate()
self.heat_exchanger.T = hx_outlet.T
self.heat_exchanger.simulate()
def _cost(self):
Design = self.design_results
baseline_purchase_costs = self.baseline_purchase_costs
volume = Design['Reactor volume']
if volume != 0:
baseline_purchase_costs.update(
self._vessel_purchase_cost(
Design['Weight'], Design['Diameter'], Design['Length'],
)
)
kW = self.kW_per_m3 * volume * self.V_wf
if kW > 0: self.agitator = bst.Agitator(kW)
ContinuousStirredTankReactor = CSTR = STR = StirredTankReactor