#################################################################################
# WaterTAP Copyright (c) 2020-2024, The Regents of the University of California,
# through Lawrence Berkeley National Laboratory, Oak Ridge National Laboratory,
# National Renewable Energy Laboratory, and National Energy Technology
# Laboratory (subject to receipt of any required approvals from the U.S. Dept.
# of Energy). All rights reserved.
#
# Please see the files COPYRIGHT.md and LICENSE.md for full copyright and license
# information, respectively. These files are also available online at the URL
# "https://github.com/watertap-org/watertap/"
#################################################################################
from pyomo.environ import (
check_optimal_termination,
units as pyunits,
Var,
)
from pyomo.common.config import ConfigBlock, ConfigValue, In
from idaes.core import (
declare_process_block_class,
MaterialBalanceType,
EnergyBalanceType,
MomentumBalanceType,
UnitModelBlockData,
useDefault,
)
from idaes.core.util.model_statistics import degrees_of_freedom
from watertap.core.solvers import get_solver
from idaes.core.util.config import is_physical_parameter_block
from idaes.core.util.exceptions import InitializationError
from idaes.core.util.tables import create_stream_table_dataframe
import idaes.logger as idaeslog
from watertap.costing.unit_models.steam_ejector import (
cost_steam_ejector,
)
from watertap.core import InitializationMixin
_log = idaeslog.getLogger(__name__)
__author__ = "Elmira Shamlou"
[docs]@declare_process_block_class("SteamEjector")
class SteamEjectorData(InitializationMixin, UnitModelBlockData):
"""
Steam Ejector model for thermal vapor compression
"""
CONFIG = ConfigBlock()
CONFIG.declare(
"dynamic",
ConfigValue(
domain=In([False]),
default=False,
description="Dynamic model flag - must be False",
doc="""Indicates whether this model will be dynamic or not,
**default** = False. The filtration unit does not support dynamic
behavior, thus this must be False.""",
),
)
CONFIG.declare(
"has_holdup",
ConfigValue(
default=False,
domain=In([False]),
description="Holdup construction flag - must be False",
doc="""Indicates whether holdup terms should be constructed or not.
**default** - False. The filtration unit does not have defined volume, thus
this must be False.""",
),
)
CONFIG.declare(
"property_package",
ConfigValue(
default=useDefault,
domain=is_physical_parameter_block,
description="Property package to use for control volume",
doc="""Property parameter object used to define property calculations,
**default** - useDefault.
**Valid values:** {
**useDefault** - use default package from parent model or flowsheet,
**PhysicalParameterObject** - a PhysicalParameterBlock object.}""",
),
)
CONFIG.declare(
"property_package_args",
ConfigBlock(
implicit=True,
description="Arguments to use for constructing property packages",
doc="""A ConfigBlock with arguments to be passed to a property block(s)
and used when constructing these,
**default** - None.
**Valid values:** {
see property package for documentation.}""",
),
)
CONFIG.declare(
"material_balance_type",
ConfigValue(
default=MaterialBalanceType.useDefault,
domain=In(MaterialBalanceType),
description="Material balance construction flag",
doc="""Indicates what type of mass balance should be constructed,
**default** - MaterialBalanceType.useDefault.
**Valid values:** {
**MaterialBalanceType.useDefault - refer to property package for default
balance type
**MaterialBalanceType.none** - exclude material balances,
**MaterialBalanceType.componentPhase** - use phase component balances,
**MaterialBalanceType.componentTotal** - use total component balances,
**MaterialBalanceType.elementTotal** - use total element balances,
**MaterialBalanceType.total** - use total material balance.}""",
),
)
CONFIG.declare(
"energy_balance_type",
ConfigValue(
default=EnergyBalanceType.useDefault,
domain=In(EnergyBalanceType),
description="Energy balance construction flag",
doc="""Indicates what type of energy balance should be constructed,
**default** - EnergyBalanceType.useDefault.
**Valid values:** {
**EnergyBalanceType.useDefault - refer to property package for default
balance type
**EnergyBalanceType.none** - exclude energy balances,
**EnergyBalanceType.enthalpyTotal** - single enthalpy balance for material,
**EnergyBalanceType.enthalpyPhase** - enthalpy balances for each phase,
**EnergyBalanceType.energyTotal** - single energy balance for material,
**EnergyBalanceType.energyPhase** - energy balances for each phase.}""",
),
)
CONFIG.declare(
"momentum_balance_type",
ConfigValue(
default=MomentumBalanceType.pressureTotal,
domain=In(MomentumBalanceType),
description="Momentum balance construction flag",
doc="""Indicates what type of momentum balance should be constructed,
**default** - MomentumBalanceType.pressureTotal.
**Valid values:** {
**MomentumBalanceType.none** - exclude momentum balances,
**MomentumBalanceType.pressureTotal** - single pressure balance for material,
**MomentumBalanceType.pressurePhase** - pressure balances for each phase,
**MomentumBalanceType.momentumTotal** - single momentum balance for material,
**MomentumBalanceType.momentumPhase** - momentum balances for each phase.}""",
),
)
[docs] def build(self):
super().build()
# State blocks
tmp_dict = dict(**self.config.property_package_args)
tmp_dict["has_phase_equilibrium"] = False
tmp_dict["parameters"] = self.config.property_package
tmp_dict["defined_state"] = True # motive steam inlet
self.properties_motive_steam = self.config.property_package.state_block_class(
self.flowsheet().config.time,
doc="Material properties of motive steam inlet",
**tmp_dict,
)
tmp_dict["defined_state"] = True # entrained vapor inlet
self.properties_entrained_vapor = (
self.config.property_package.state_block_class(
self.flowsheet().config.time,
doc="Material properties of entrained vapor inlet",
**tmp_dict,
)
)
tmp_dict["defined_state"] = False
self.properties_discharge_mix = self.config.property_package.state_block_class(
self.flowsheet().config.time,
doc="Material properties of discharge mix",
**tmp_dict,
)
# Ports
self.add_port(name="inlet_motive_steam", block=self.properties_motive_steam)
self.add_port(
name="inlet_entrained_vapor", block=self.properties_entrained_vapor
)
self.add_port(name="outlet_discharge_mix", block=self.properties_discharge_mix)
self.PCF = Var(
initialize=1.0,
units=pyunits.dimensionless,
doc="Pressure correction factor",
)
self.TCF = Var(
initialize=1.0,
bounds=(None, 4),
units=pyunits.dimensionless,
doc="Temperature correction factor",
)
self.entrainment_ratio = Var(
initialize=0.5,
bounds=(0, 4),
units=pyunits.dimensionless,
doc="Entrainment ratio",
)
# The bounds of compression ratio variable corresponds to the validity range of entrainment ratio semi-empirical model
self.compression_ratio = Var(
initialize=2,
bounds=(1.89, None),
units=pyunits.dimensionless,
doc="Compression ratio",
)
# Empirical correlation constraints
@self.Constraint(doc="Pressure Correction Factor (El-Dessouky, 1997)")
def eq_PCF(b):
A_PCF = 3e-7 / pyunits.kPa**2
B_PCF = -0.0009 / pyunits.kPa
C_PCF = 1.6101
return (
b.PCF
== A_PCF
* pyunits.convert(
b.properties_motive_steam[0].pressure, to_units=pyunits.kPa
)
** 2
- B_PCF
* pyunits.convert(
b.properties_motive_steam[0].pressure, to_units=pyunits.kPa
)
+ C_PCF
)
@self.Constraint(doc="Temperature Correction Factor (El-Dessouky, 1997)")
def eq_TCF(b):
A_TCF = 2e-8 / (pyunits.K**2)
B_TCF = 0.0006 / pyunits.K
C_TCF = 1.0047
return (
b.TCF
== A_TCF
* (b.properties_entrained_vapor[0].temperature - 273.15 * pyunits.K)
** 2
- B_TCF
* (b.properties_entrained_vapor[0].temperature - 273.15 * pyunits.K)
+ C_TCF
)
@self.Constraint(
doc="Entrainment Ratio semi-empirical model (El-Dessouky, 1997)"
)
def eq_entrainment_ratio_model(b):
# Convert pressures to kPa
P_discharge_kPa = pyunits.convert(
b.properties_discharge_mix[0].pressure, to_units=pyunits.kPa
)
P_entrained_kPa = pyunits.convert(
b.properties_entrained_vapor[0].pressure, to_units=pyunits.kPa
)
P_motive_kPa = pyunits.convert(
b.properties_motive_steam[0].pressure, to_units=pyunits.kPa
)
P_discharge_dim = P_discharge_kPa / (1 * pyunits.kPa) # Dimensionless
P_entrained_dim = P_entrained_kPa / (1 * pyunits.kPa) # Dimensionless
P_motive_dim = P_motive_kPa / (1 * pyunits.kPa) # Dimensionless
return b.entrainment_ratio * b.TCF == (
0.296
* (P_discharge_dim**1.19)
/ (P_entrained_dim**1.04)
* (P_motive_dim / P_entrained_dim) ** 0.015
* b.PCF
)
@self.Constraint(doc="Entrainment Ratio Definition (El-Dessouky, 1997)")
def eq_entrainment_ratio(b):
return (
b.entrainment_ratio
== b.properties_motive_steam[0].flow_mass_phase_comp["Vap", "H2O"]
/ b.properties_entrained_vapor[0].flow_mass_phase_comp["Vap", "H2O"]
)
@self.Constraint(doc="Compression Ratio Definition")
def eq_compression_ratio(b):
return (
b.compression_ratio
== b.properties_discharge_mix[0].pressure
/ b.properties_entrained_vapor[0].pressure
)
@self.Constraint(self.flowsheet().time, doc="Mass Balance")
# assume vapor enters the ejector after passing through the demister
def eq_mass_balance(b, t):
lb = b.properties_discharge_mix[t].flow_mass_phase_comp["Liq", "H2O"].lb
b.properties_discharge_mix[t].flow_mass_phase_comp["Liq", "H2O"].fix(lb)
return b.properties_discharge_mix[t].flow_mass_phase_comp["Vap", "H2O"] == (
b.properties_motive_steam[t].flow_mass_phase_comp["Vap", "H2O"]
+ b.properties_entrained_vapor[t].flow_mass_phase_comp["Vap", "H2O"]
)
# Assumes the discharge mix pressure to be equal to its saturation pressure
@self.Constraint(
self.flowsheet().time, doc="Discharge Temperature and Pressure Relationship"
)
def eq_discharge_temperature_pressure(b, t):
return (
b.properties_discharge_mix[t].pressure
== b.properties_discharge_mix[t].pressure_sat
)
[docs] def initialize_build(
self, state_args=None, outlvl=idaeslog.NOTSET, solver=None, optarg=None
):
"""
General wrapper for steam ejector initialization routines
Keyword Arguments:
state_args : a dict of arguments to be passed to the property
package(s) to provide an initial state for
initialization (see documentation of the specific
property package) (default = {}).
outlvl : sets output level of initialization routine
optarg : solver options dictionary object (default=None)
solver : str indicating which solver to use during
initialization (default = None)
Returns: None
"""
init_log = idaeslog.getInitLogger(self.name, outlvl, tag="unit")
solve_log = idaeslog.getSolveLogger(self.name, outlvl, tag="unit")
# Set solver options
opt = get_solver(solver, optarg)
# ---------------------------------------------------------------------
# Initialize state blocks
self.properties_motive_steam.initialize(
solver=solver, optarg=optarg, outlvl=outlvl, state_args=state_args
)
init_log.info_high("Motive steam inlet initialization complete")
self.properties_entrained_vapor.initialize(
solver=solver, optarg=optarg, outlvl=outlvl, state_args=state_args
)
init_log.info_high("Entrained vapor inlet initialization complete")
state_args_discharge = {}
state_dict_motive = self.properties_motive_steam[
self.flowsheet().config.time.first()
].define_port_members()
state_dict_entrained = self.properties_entrained_vapor[
self.flowsheet().config.time.first()
].define_port_members()
for k in state_dict_motive.keys():
if state_dict_motive[k].is_indexed():
state_args_discharge[k] = {}
for m in state_dict_motive[k].keys():
state_args_discharge[k][m] = (
state_dict_motive[k][m].value + state_dict_entrained[k][m].value
)
else:
state_args_discharge[k] = 0.5 * (
state_dict_motive[k].value + state_dict_entrained[k].value
)
self.properties_discharge_mix.initialize(
solver=solver, optarg=optarg, outlvl=outlvl, state_args=state_args_discharge
)
init_log.info_high("Discharge mix initialization complete")
if degrees_of_freedom(self) != 0:
raise Exception(
f"{self.name} degrees of freedom were not 0 at the beginning "
f"of initialization. DoF = {degrees_of_freedom(self)}"
)
# Solve unit
with idaeslog.solver_log(solve_log, idaeslog.DEBUG) as slc:
res = opt.solve(self, tee=slc.tee)
init_log.info_high(
"Initialization steam ejector {}.".format(idaeslog.condition(res))
)
# ---------------------------------------------------------------------
# Release state
if not check_optimal_termination(res):
raise InitializationError(f"Unit model {self.name} failed to initialize")
init_log.info("Initialization Complete: {}".format(idaeslog.condition(res)))
def _get_performance_contents(self, time_point=0):
var_dict = {
"Entrainment ratio": self.entrainment_ratio,
"Compression ratio": self.compression_ratio,
}
return {"vars": var_dict}
def _get_stream_table_contents(self, time_point=0):
return create_stream_table_dataframe(
{
"Motive steam": self.inlet_motive_steam,
"inlet_entrained_vapor": self.inlet_entrained_vapor,
"outlet_discharge_mix": self.outlet_discharge_mix,
},
time_point=time_point,
)
def calculate_scaling_factors(self):
super().calculate_scaling_factors()
@property
def default_costing_method(self):
return cost_steam_ejector