# -*- coding: utf-8 -*-
# BioSTEAM: The Biorefinery Simulation and Techno-Economic Analysis Modules
# Copyright (C) 2020, 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.
"""
"""
from .. import Unit, PowerUtility
from thermosteam import MultiStream, separations
from math import pi
import numpy as np
from . import design_tools as design
from .splitting import Splitter
from .heat_exchange import HX, HXutility
from thermosteam._graphics import vertical_vessel_graphics
import biosteam as bst
exp = np.exp
ln = np.log
# USDA Biodiesel:
#V = np.pi*D**2/4*Ht*0.3048**3
#if not (0.1 < V < 70):
# raise DesignError(f"Volume is out of bounds for costing")
#lambda V, CE: CE*13*V**0.62 # V (m3)
__all__ = ('Flash', 'SplitFlash')
# %% Flash
[docs]
class Flash(design.PressureVessel, Unit):
"""
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 :
Inlet fluid.
outs :
* [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
----------
.. [1] "Design Two-Phase Separators Within the Right Limits", Chemical
Engineering Progress Oct, 1993.
.. [2] Mulet, A., A. B. Corripio, and L. B. Evans, “Estimate Costs of
Pressure Vessels via Correlations,” Chem. Eng., 88(20), 145–150 (1981a).
.. [3] Mulet, A., A.B. Corripio, and L.B.Evans, “Estimate Costs of
Distillation and Absorption Towers via Correlations,” Chem. Eng., 88(26), 77–82 (1981b).
.. [4] Seider, W. D., Lewin, D. R., Seader, J. D., Widagdo, S., Gani,
R., & Ng, M. K. (2017). Product and Process Design Principles. Wiley.
Cost Accounting and Capital Cost Estimation (Chapter 16)
"""
auxiliary_unit_names = ('heat_exchanger', 'vacuum_system', 'vapor_condenser')
_auxin_index = {
'heat_exchanger': 0
}
_units = {'Length': 'ft',
'Diameter': 'ft',
'Weight': 'lb',
'Wall thickness': 'in',
'Total volume': 'ft3'}
_max_agile_design = (
'Length',
'Diameter',
'Weight',
'Wall thickness',
)
_F_BM_default = {'Liquid-ring pump': 1.0,
**design.PressureVessel._F_BM_default}
_graphics = vertical_vessel_graphics
_N_outs = 2
def _init(self,
V=None, T=None, Q=None, P=None, y=None, x=None,
vessel_material='Carbon steel',
vacuum_system_preference='Liquid-ring pump',
has_glycol_groups=False,
has_amine_groups=False,
vessel_type=None,
holdup_time=15,
surge_time=7.5,
has_mist_eliminator=False,
flash_inlet=True,
has_vapor_condenser=None,
):
#: Enforced molar vapor fraction
self.V = V
#: Enforced operating temperature (K)
self.T = T
#: [array_like] Molar composition of vapor (for binary mixture)
self.y = y
#: [array_like] Molar composition of liquid (for binary mixture)
self.x = x
#: Enforced duty (kJ/hr)
self.Q = Q
#: Operating pressure (Pa)
self.P = P
#: [str] Vessel construction material
self.vessel_material = vessel_material
#: [str] If a vacuum system is needed, it will choose one according to this preference.
self.vacuum_system_preference = vacuum_system_preference
#: [bool] True if glycol groups are present in the mixture
self.has_glycol_groups = has_glycol_groups
#: [bool] True if amine groups are present in the mixture
self.has_amine_groups = has_amine_groups
#: [str] 'Horizontal', 'Vertical', or 'Default'
self.vessel_type = vessel_type
#: [float] Time it takes to raise liquid to half full (min)
self.holdup_time = holdup_time
#: [float] Time it takes to reach from normal to maximum liquied level (min)
self.surge_time = surge_time
#: [bool] True if using a mist eliminator pad
self.has_mist_eliminator = has_mist_eliminator
#: [bool] Whether to flash inlet. If inlet is already flashed,
#: False can save simulation time.
self.flash_inlet = flash_inlet
#: [bool] Whether to condense the vapor leaving the flash. This allows
#: vacuum systems to operate more efficiently.
self.has_vapor_condenser = has_vapor_condenser
self._load_components()
def _load_components(self):
self._multi_stream = ms = MultiStream(None, thermo=self.thermo)
self.auxiliary(
'heat_exchanger', HXutility, ins=self.feed, outs=ms
)
if self.has_vapor_condenser:
self.auxiliary(
'vapor_condenser', HXutility, ins='vapor',
outs=self.outs[0], V=0, rigorous=True,
)
def reset_cache(self, isdynamic=None):
self._multi_stream.reset_cache()
self.heat_exchanger.reset_cache()
@property
def P(self):
"""Operating pressure (Pa)."""
return self._P
@P.setter
def P(self, P):
if P and P < 101325 and not self.power_utility:
self.power_utility = PowerUtility()
self._P = P
@property
def vapor(self):
"""Outlet vapor stream (equivalent to outs[0])."""
return self._outs[0]
@vapor.setter
def vapor(self, vapor):
self._outs[0] = vapor
@property
def liquid(self):
"""Outlet liquid stream (equivalent to outs[1])."""
return self._outs[1]
@liquid.setter
def liquid(self, liquid):
self._outs[1] = liquid
def _default_vessel_type(self):
vap, liq = self.outs
F_mass_vap = vap.F_mass
F_mass_liq = liq.F_mass
return 'Vertical' if F_mass_vap / F_mass_liq >= 1 else 'Horizontal'
def _run(self):
separations.vle(self.ins[0], *self.outs, self.T, self.P, self.V,
self.Q, self.x, self.y, self._multi_stream)
if self.has_vapor_condenser:
self.vapor_condenser.ins[0].copy_like(self.outs[0])
self.vapor_condenser.run()
def _size_flash_vessel(self):
vap, liq, *_ = self.outs
self.no_vessel_needed = vap.isempty() or liq.isempty()
if self.no_vessel_needed:
self.design_results.clear()
else:
vessel_type = self.vessel_type
if vessel_type == 'Vertical':
args = self._vertical_vessel_pressure_diameter_and_length()
elif vessel_type == 'Horizontal':
args = self._horizontal_vessel_pressure_diameter_and_length()
else: raise RuntimeError('unknown vessel type') # pragma: no cover
self.design_results.update(
self._vessel_design(*args)
)
def _design(self):
self._size_flash_vessel()
if self.Q == 0.:
self.heat_exchanger._setup() # Removes results
else:
self.heat_exchanger.simulate_as_auxiliary_exchanger(self.ins, self.outs, vle=self.flash_inlet)
def _cost(self):
D = self.design_results
if not self.no_vessel_needed:
self.baseline_purchase_costs.update(
self._vessel_purchase_cost(D['Weight'], D['Diameter'], D['Length'])
)
self._cost_vacuum()
def _cost_vacuum(self):
P = self.P
if not P or P > 101320:
self.vacuum_system = None
else:
Design = self.design_results
R = Design['Diameter'] * 0.5
volume = 0.02832 * np.pi * Design['Length'] * R * R # Volume ft3 to m3
self.vacuum_system = bst.VacuumSystem(
self, self.vacuum_system_preference, vessel_volume=volume,
)
def _design_parameters(self):
# Retrieve run_args and properties
vap, liq, *_ = self._outs
rhov = vap.get_property('rho', 'lb/ft3')
rhol = liq.get_property('rho', 'lb/ft3')
P = liq.get_property('P', 'psi') # Pressure (psi)
vessel_type = self.vessel_type
Th = self.holdup_time
Ts = self.surge_time
has_mist_eliminator = self.has_mist_eliminator
# Calculate the volumetric flowrate
Qv = vap.get_total_flow('ft^3 / s')
Qll = liq.get_total_flow('ft^3 / min')
# Calculate Ut and set Uv
K = design.compute_Stokes_law_York_Demister_K_value(P)
# Adjust K value
if not has_mist_eliminator and vessel_type == 'Vertical': K /= 2
# Adjust for amine or glycol groups:
if self.has_glycol_groups: K *= 0.6
elif self.has_amine_groups: K *= 0.8
Ut = K*((rhol - rhov) / rhov)**0.5
Uv = 0.75*Ut
# Calculate Holdup and Surge volume
Vh = Th*Qll
Vs = Ts*Qll
return rhov, rhol, P, Th, Ts, has_mist_eliminator, Qv, Qll, Ut, Uv, Vh, Vs
def _vertical_vessel_pressure_diameter_and_length(self):
rhov, rhol, P, Th, Ts, has_mist_eliminator, Qv, Qll, Ut, Uv, Vh, Vs = self._design_parameters()
# Calculate internal diameter, Dvd
Dvd = (4.0*Qv/(pi*Uv))**0.5
if has_mist_eliminator:
D = design.ceil_half_step(Dvd + 0.4)
else:
D = design.ceil_half_step(Dvd)
# Obtaining low liquid level height, Hlll
Hlll = 0.5
if P < 300:
Hlll = 1.25
# Calculate the height from Hlll to Normal liquid level, Hnll
Hh = Vh/(pi/4.0*Dvd**2)
if Hh < 1.0: Hh = 1.0
# Calculate the height from Hnll to High liquid level, Hhll
Hs = Vs/(pi/4.0*Dvd**2)
if Hs < 0.5: Hs = 0.5
# Calculate dN
Qm = Qll / 60 + Qv
lamda = Qll / 60 / Qm
rhoM = rhol * lamda + rhov * (1 - lamda)
dN = (4*Qm / (pi * 60.0 / (rhoM**0.5)))**0.5
dN = design.ceil_half_step(dN)
# Calculate Hlin, assume with inlet diverter
Hlin = 1.0 + dN
# Calculate the vapor disengagement height
Hv = 0.5*Dvd
Hv2 = (2.0 if has_mist_eliminator else 3.0) + dN/2.0 # pragma: no cover
if Hv2 < Hv: Hv = Hv2
Hv = Hv
# Calculate total height, Ht
Hme = 1.5 if has_mist_eliminator else 0.0
Ht = Hlll + Hh + Hs + Hlin + Hv + Hme
Ht = design.ceil_half_step(Ht)
# Find maximum and normal liquid level
# Hhll = Hs + Hh + Hlll
# Hnll = Hh + Hlll
return P, D, Ht
def _horizontal_vessel_pressure_diameter_and_length(self):
rhov, rhol, P, Th, Ts, has_mist_eliminator, Qv, Qll, Ut, Uv, Vh, Vs = self._design_parameters()
# Initialize LD
if P > 0 and P <= 264.7:
LD = 1.5/250.0*(P-14.7)+1.5
elif P > 264.7 and P <= 514.7: # pragma: no cover
LD = 1.0/250.0*(P-14.7)+2.0
elif P > 514.7: # pragma: no cover
LD = 5.0
D = (4.0*(Vh+Vs)/(0.6*pi*LD))**(1.0/3.0)
if D <= 4.0:
D = 4.0
else:
D = design.ceil_half_step(D)
for outerIter in range(50):
At = pi*(D**2)/4.0 # Total area
# Calculate Lower Liquid Area
Hlll = round(0.5*D + 7.0)
Hlll = Hlll/12.0 # D is in ft but Hlll is in inches
X = Hlll/D
Y = design.HNATable(1, X)
Alll = Y*At
# Calculate the Vapor disengagement area, Av
Hv = 0.2*D
if has_mist_eliminator and Hv <= 2.0: Hv = 2.0
elif Hv <= 1.0: Hv = 1.0
else: Hv = design.ceil_half_step(Hv)
Av = design.HNATable(1, Hv/D)*At
# Calculate minimum length for surge and holdup
L = (Vh + Vs)/(At - Av - Alll)
# Calculate liquid dropout
Phi = Hv/Uv
# Calculate actual vapor velocity
Uva = Qv/Av
# Calculate minimum length for vapor disengagement
Lmin = Uva*Phi
Li = L
for innerIter in range(50):
if L < 0.8*Lmin: Hv += 0.5
elif L > 1.2*Lmin:
if has_mist_eliminator and Hv <= 2.0: Hv = 2.0
elif not has_mist_eliminator and Hv <= 1.0: Hv = 1.0
else: Hv -= 0.5
else: break
Av = design.HNATable(1, Hv/D)*At
Alll = design.HNATable(1, Hlll/D)*At
Li = (Vh + Vs)/(At - Av - Alll)
Phi = Hv/Uv
Uva = Qv/Av
Lmin = Uva*Phi
L = Li
LD = L/D
# Check LD
if LD < 1.2:
if D <= 4.0: break
else: D -= 0.5
if LD > 7.2: # pragma: no cover
D += 0.5
else: break
# Recalculate LD so it lies between 1.5 - 6.0
while True:
LD = L / D
if (LD < 1.5) and D <= 4.0: L += 0.5
elif LD < 1.5: D -= 0.5
elif (LD > 6.0): D += 0.5
else: break
# # To check minimum Hv value
# if int(has_mist_eliminator) == 1 and Hv <= 2.0:
# Hv = 2.0
# if int(has_mist_eliminator) == 0 and Hv <= 1.0:
# Hv = 1.0
# Calculate normal liquid level and High liquid level
# Hhll = D - Hv
# if (Hhll < 0.0):
# Hhll = 0.0
# Anll = Alll + Vh/L
# X = Anll/At
# Y = HNATable(2, X)
# Hnll = Y*D
return P, D, L
# %% Special
class SplitFlash(Flash):
line = 'Flash'
def _init(self, split,
order=None, T=None, P=None, Q=None,
vessel_material='Carbon steel',
vacuum_system_preference='Liquid-ring pump',
has_glycol_groups=False,
has_amine_groups=False,
vessel_type=None,
holdup_time=15,
surge_time=7.5,
has_mist_eliminator=False,
has_vapor_condenser=False,
):
Splitter._init(self, split=split, order=order)
self.has_vapor_condenser = has_vapor_condenser
self._load_components()
self.T = T #: Operating temperature (K)
self.P = P #: Operating pressure (Pa)
self.Q = Q #: Duty (kJ/hr)
#: [str] Vessel construction material
self.vessel_material = vessel_material
#: [str] If a vacuum system is needed, it will choose one according to this preference.
self.vacuum_system_preference = vacuum_system_preference
#: [bool] True if glycol groups are present in the mixture
self.has_glycol_groups = has_glycol_groups
#: [bool] True if amine groups are present in the mixture
self.has_amine_groups = has_amine_groups
#: [str] 'Horizontal', 'Vertical', or 'Default'
self.vessel_type = vessel_type
#: [float] Time it takes to raise liquid to half full (min)
self.holdup_time = holdup_time
#: [float] Time it takes to reach from normal to maximum liquied level (min)
self.surge_time = surge_time
#: [bool] True if using a mist eliminator pad
self.has_mist_eliminator = has_mist_eliminator
self.flash_inlet = False
isplit = Splitter.isplit
split = Splitter.split
V = None
def _run(self):
top, bot = self.outs
feed, = self.ins
feed_mol = feed.mol
top.phase = 'g'
bot.phase = 'l'
top.mol[:] = top_mol = feed_mol * self.split
bot.mol[:] = feed_mol - top_mol
bot.T = top.T = self.T
bot.P = top.P = self.P
def _design(self):
self.heat_exchanger.simulate_as_auxiliary_exchanger(self.ins, self.outs, vle=False)
super()._design()
# %% Single Component for MultiEffectEvaporator
class Evaporator(Flash):
_ins_size_is_fixed = True
_N_ins = 2
_N_outs = 3
@property
def P(self):
return self._P
@P.setter
def P(self, P):
if P is None:
self._Hvap = self._P = self._T = None
else:
chemical = self.chemical
self._T = T = chemical.Tsat(P)
self._Hvap = chemical.Hvap(T)
self._P = P
@property
def T(self):
return self._T
@T.setter
def T(self, T): # pragma: no cover
if T is None:
self._Hvap = self._P = self._T = None
else:
chemical = self.chemical
self._P = chemical.Psat(T)
self._T = T
def _init(self, Q=None, V=None, P=101325, chemical='7732-18-5'):
super()._init(vessel_type='Vertical')
self.chemical = self.chemicals[chemical]
self.P = P
self.Q = Q
self.V = V
def _load_components(self): pass
def _run(self):
feed, utility_vapor = self.ins
vapor, liquid, utility_liquid = self.outs
u_given = not utility_vapor.isempty()
Q_given = self.Q is not None
V_given = self.V is not None
N_specs = u_given + Q_given + V_given
if N_specs > 1:
raise RuntimeError('can specify at most one of the following: Q, V, or utility vapor')
if Q_given:
Q = self.Q
elif u_given:
# Q can come from condensing a side stream
utility_liquid.copy_like(utility_vapor)
utility_liquid.phase = 'l'
Q = utility_vapor.Hvap
Q_given = True
elif V_given:
V = self.V
else:
# Default to no heat transfer
Q = 0
Q_given = True
feed_H = feed.H
# Set exit conditions
vapor.T = liquid.T = self.T
vapor.P = liquid.P = self.P
liquid.phase = 'l'
vapor.phase = 'g'
liquid.copy_flow(feed)
chemical_ID = self.chemical.ID
if Q_given:
# Energy balance to find vapor fraction
f = feed.imol[chemical_ID]
H = feed_H + Q
if f:
Hvap = f * self._Hvap
dH = (H - liquid.H)
V = dH / Hvap
if V < 0:
vapor.imol[chemical_ID] = 0
liquid.imol[chemical_ID] = f
liquid.H = H
elif V > 1:
vapor.imol[chemical_ID] = f
liquid.imol[chemical_ID] = 0
try:
vapor.H = H
except RuntimeError: # Extrapolation failed
vapor.phase = 'g'
vapor.T = vapor.chemicals[chemical_ID].Tc
else:
vapor.imol[chemical_ID] = f * V
liquid.imol[chemical_ID] = (1 - V) * f
else:
V = 0
Q = 0
elif V_given:
# Specify fraction evaporated and compute Q
V = self.V
chemical_mol = feed.imol[chemical_ID]
liquid.copy_flow(feed)
liquid.imol[chemical_ID] = (1 - V) * chemical_mol
vapor.imol[chemical_ID] = V * chemical_mol
Q = liquid.H + vapor.H - feed.H
self.design_results['Heat transfer'] = Q
