def test_mixer2():
m = pyo.ConcreteModel()
m.fs = idaes.core.FlowsheetBlock(default={"dynamic": False})
m.fs.properties = iapws95.Iapws95ParameterBlock()
m.fs.unit = HelmMixer(
default={
"momentum_mixing_type": MomentumMixingType.equality,
"property_package": m.fs.properties,
"inlet_list": ["i1", "i2", "i3"]
})
Fin1 = 1.1e4 # mol/s
hin1 = 4000 # J/mol
Pin1 = 1.2e5 # Pa
Fin2 = 1e4 # mol/s
hin2 = 5000 # J/mol
Pin2 = 2e5 # Pa
Fin3 = 1.3e4 # mol/s
hin3 = 6000 # J/mol
Pin3 = 3e5 # Pa
Pout = 1.5e5 # Pa
m.fs.unit.i1.flow_mol[0].fix(Fin1)
m.fs.unit.i1.enth_mol[0].fix(hin1)
m.fs.unit.i1.pressure[0] = Pin1
m.fs.unit.i2.flow_mol[0].fix(Fin2)
m.fs.unit.i2.enth_mol[0].fix(hin2)
m.fs.unit.i2.pressure[0] = Pin2
m.fs.unit.i3.flow_mol[0].fix(Fin3)
m.fs.unit.i3.enth_mol[0].fix(hin3)
m.fs.unit.i3.pressure[0] = Pin3
m.fs.unit.outlet.pressure[0].fix(Pout)
m.fs.unit.initialize()
Fout = Fin1 + Fin2 + Fin3
hout = (hin1 * Fin1 + hin2 * Fin2 + hin3 * Fin3) / Fout
assert pyo.value(m.fs.unit.outlet.flow_mol[0]) == pytest.approx(Fout,
rel=1e-7)
assert pyo.value(m.fs.unit.outlet.enth_mol[0]) == pytest.approx(hout,
rel=1e-7)
assert pyo.value(m.fs.unit.outlet.pressure[0]) == pytest.approx(Pout,
rel=1e-7)
assert pyo.value(m.fs.unit.i1.pressure[0]) == pytest.approx(Pout, rel=1e-7)
assert pyo.value(m.fs.unit.i2.pressure[0]) == pytest.approx(Pout, rel=1e-7)
assert pyo.value(m.fs.unit.i3.pressure[0]) == pytest.approx(Pout, rel=1e-7)
def create_model():
"""Create the flowsheet and add unit models. Fixing model inputs is done
in a separate function to try to keep this fairly clean and easy to follow.
Args:
None
Returns:
(ConcreteModel) Steam cycle model
"""
############################################################################
# Flowsheet and Properties #
############################################################################
m = pyo.ConcreteModel(name="Steam Cycle Model")
m.fs = FlowsheetBlock(default={"dynamic":
False}) # Add steady state flowsheet
# A physical property parameter block for IAPWS-95 with pressure and enthalpy
# (PH) state variables. Usually pressure and enthalpy state variables are
# more robust especially when the phases are unknown.
m.fs.prop_water = iapws95.Iapws95ParameterBlock(
default={"phase_presentation": iapws95.PhaseType.MIX})
# A physical property parameter block with temperature, pressure and vapor
# fraction (TPx) state variables. There are a few instances where the vapor
# fraction is known and the temperature and pressure state variables are
# preferable.
m.fs.prop_water_tpx = iapws95.Iapws95ParameterBlock(
default={
"phase_presentation": iapws95.PhaseType.LG,
"state_vars": iapws95.StateVars.TPX,
})
############################################################################
# Turbine with fill-in reheat constraints #
############################################################################
# The TurbineMultistage class allows creation of the full turbine model by
# providing several configuration options, including: throttle valves;
# high-, intermediate-, and low-pressure sections; steam extractions; and
# pressure driven flow. See the IDAES documentation for details.
m.fs.turb = HelmTurbineMultistage(
default={
"property_package": m.fs.prop_water,
"num_parallel_inlet_stages": 4, # number of admission arcs
"num_hp": 7, # number of high-pressure stages
"num_ip": 10, # number of intermediate-pressure stages
"num_lp": 11, # number of low-pressure stages
"hp_split_locations": [4, 7], # hp steam extraction locations
"ip_split_locations": [5, 10], # ip steam extraction locations
"lp_split_locations": [4, 8, 10, 11
], # lp steam extraction locations
"hp_disconnect": [7], # disconnect hp from ip to insert reheater
"ip_split_num_outlets": {
10: 3
}, # number of split streams (default is 2)
})
# This model is only the steam cycle, and the reheater is part of the boiler.
# To fill in the reheater gap, a few constraints for the flow, pressure drop,
# and outlet temperature are added. A detailed boiler model can be coupled later.
#
# hp_split[7] is the splitter directly after the last HP stage. The splitter
# outlet "outlet_1" is always taken to be the main steam flow through the turbine.
# When the turbine model was instantiated the stream from the HP section to the IP
# section was omitted, so the reheater could be inserted.
# The flow constraint sets flow from outlet_1 of the splitter equal to
# flow into the IP turbine.
@m.fs.turb.Constraint(m.fs.time)
def constraint_reheat_flow(b, t):
return b.ip_stages[1].inlet.flow_mol[t] == b.hp_split[
7].outlet_1.flow_mol[t]
# Create a variable for pressure change in the reheater (assuming
# reheat_delta_p should be negative).
m.fs.turb.reheat_delta_p = pyo.Var(m.fs.time,
initialize=0,
units=pyo.units.Pa)
# Add a constraint to calculate the IP section inlet pressure based on the
# pressure drop in the reheater and the outlet pressure of the HP section.
@m.fs.turb.Constraint(m.fs.time)
def constraint_reheat_press(b, t):
return (b.ip_stages[1].inlet.pressure[t] ==
b.hp_split[7].outlet_1.pressure[t] + b.reheat_delta_p[t])
# Create a variable for reheat temperature and fix it to the desired reheater
# outlet temperature
m.fs.turb.reheat_out_T = pyo.Var(m.fs.time,
initialize=866,
units=pyo.units.K)
# Create a constraint for the IP section inlet temperature.
@m.fs.turb.Constraint(m.fs.time)
def constraint_reheat_temp(b, t):
return (b.ip_stages[1].control_volume.properties_in[t].temperature ==
b.reheat_out_T[t])
############################################################################
# Add Condenser/hotwell/condensate pump #
############################################################################
# Add a mixer for all the streams coming into the condenser. In this case the
# main steam, and the boiler feed pump turbine outlet go to the condenser
m.fs.condenser_mix = HelmMixer(
default={
"momentum_mixing_type": MomentumMixingType.none,
"inlet_list": ["main", "bfpt"],
"property_package": m.fs.prop_water,
})
# The pressure in the mixer comes from the connection to the condenser. All
# the streams coming in and going out of the mixer are equal, but we created
# the mixer with no calculation for the unit pressure. Here a constraint that
# specifies that the mixer pressure is equal to the main steam pressure is
# added. There is also a constraint that specifies the that BFP turbine outlet
# pressure is the same as the condenser pressure. Combined with the stream
# connections between units, these constraints effectively specify that the
# mixer inlet and outlet streams all have the same pressure.
@m.fs.condenser_mix.Constraint(m.fs.time)
def mixer_pressure_constraint(b, t):
return b.main_state[t].pressure == b.mixed_state[t].pressure
# The condenser model uses the physical property model with TPx state
# variables, while the rest of the model uses PH state variables. To
# translate between the two property calculations, an extra port is added to
# the mixer which contains temperature, pressure, and vapor fraction
# quantities.
m.fs.condenser_mix.outlet_tpx = Port(
initialize={
"flow_mol":
pyo.Reference(m.fs.condenser_mix.mixed_state[:].flow_mol),
"temperature":
pyo.Reference(m.fs.condenser_mix.mixed_state[:].temperature),
"pressure":
pyo.Reference(m.fs.condenser_mix.mixed_state[:].pressure),
"vapor_frac":
pyo.Reference(m.fs.condenser_mix.mixed_state[:].vapor_frac),
})
# Add the heat exchanger model for the condenser.
m.fs.condenser = HeatExchanger(
default={
"delta_temperature_callback": delta_temperature_underwood_callback,
"shell": {
"property_package": m.fs.prop_water_tpx
},
"tube": {
"property_package": m.fs.prop_water
},
})
m.fs.condenser.delta_temperature_out.fix(5)
# Everything condenses so the saturation pressure determines the condenser
# pressure. Deactivate the constraint that is used in the TPx version vapor
# fraction constraint and fix vapor fraction to 0.
m.fs.condenser.shell.properties_out[:].eq_complementarity.deactivate()
m.fs.condenser.shell.properties_out[:].vapor_frac.fix(0)
# There is some subcooling in the condenser, so we assume the condenser
# pressure is actually going to be slightly higher than the saturation
# pressure.
m.fs.condenser.pressure_over_sat = pyo.Var(
m.fs.time,
initialize=500,
doc="Pressure added to Psat in the condeser. This is to account for"
"some subcooling. (Pa)",
units=pyo.units.Pa)
# Add a constraint for condenser pressure
@m.fs.condenser.Constraint(m.fs.time)
def eq_pressure(b, t):
return (b.shell.properties_out[t].pressure ==
b.shell.properties_out[t].pressure_sat +
b.pressure_over_sat[t])
# Extra port on condenser to hook back up to pressure-enthalpy properties
m.fs.condenser.outlet_1_ph = Port(
initialize={
"flow_mol":
pyo.Reference(m.fs.condenser.shell.properties_out[:].flow_mol),
"pressure":
pyo.Reference(m.fs.condenser.shell.properties_out[:].pressure),
"enth_mol":
pyo.Reference(m.fs.condenser.shell.properties_out[:].enth_mol),
})
# Add the condenser hotwell. In steady state a mixer will work. This is
# where makeup water is added if needed.
m.fs.hotwell = HelmMixer(
default={
"momentum_mixing_type": MomentumMixingType.none,
"inlet_list": ["condensate", "makeup"],
"property_package": m.fs.prop_water,
})
# The hotwell is assumed to be at the same pressure as the condenser.
@m.fs.hotwell.Constraint(m.fs.time)
def mixer_pressure_constraint(b, t):
return b.condensate_state[t].pressure == b.mixed_state[t].pressure
# Condensate pump (Use compressor model, since it is more robust if vapor form)
m.fs.cond_pump = HelmIsentropicCompressor(
default={"property_package": m.fs.prop_water})
############################################################################
# Add low pressure feedwater heaters #
############################################################################
# All the feedwater heater sections will be set to use the Underwood
# approximation for LMTD, so create the fwh_config dict to make the config
# slightly cleaner
fwh_config = {
"delta_temperature_callback": delta_temperature_underwood_callback
}
# The feedwater heater model allows feedwater heaters with a desuperheat,
# condensing, and subcooling section to be added an a reasonably simple way.
# See the IDAES documentation for more information of configuring feedwater
# heaters
m.fs.fwh1 = FWH0D(
default={
"has_desuperheat": False,
"has_drain_cooling": False,
"has_drain_mixer": True,
"property_package": m.fs.prop_water,
"condense": fwh_config,
})
# pump for fwh1 condensate, to pump it ahead and mix with feedwater
m.fs.fwh1_pump = HelmIsentropicCompressor(
default={"property_package": m.fs.prop_water})
# Mix the FWH1 drain back into the feedwater
m.fs.fwh1_return = HelmMixer(
default={
"momentum_mixing_type": MomentumMixingType.none,
"inlet_list": ["feedwater", "fwh1_drain"],
"property_package": m.fs.prop_water,
})
# Set the mixer pressure to the feedwater pressure
@m.fs.fwh1_return.Constraint(m.fs.time)
def mixer_pressure_constraint(b, t):
return b.feedwater_state[t].pressure == b.mixed_state[t].pressure
# Add the rest of the low pressure feedwater heaters
m.fs.fwh2 = FWH0D(
default={
"has_desuperheat": True,
"has_drain_cooling": True,
"has_drain_mixer": True,
"property_package": m.fs.prop_water,
"desuperheat": fwh_config,
"cooling": fwh_config,
"condense": fwh_config,
})
m.fs.fwh3 = FWH0D(
default={
"has_desuperheat": True,
"has_drain_cooling": True,
"has_drain_mixer": True,
"property_package": m.fs.prop_water,
"desuperheat": fwh_config,
"cooling": fwh_config,
"condense": fwh_config,
})
m.fs.fwh4 = FWH0D(
default={
"has_desuperheat": True,
"has_drain_cooling": True,
"has_drain_mixer": False,
"property_package": m.fs.prop_water,
"desuperheat": fwh_config,
"cooling": fwh_config,
"condense": fwh_config,
})
############################################################################
# Add deaerator and boiler feed pump (BFP) #
############################################################################
# The deaerator is basically an open tank with multiple inlets. For steady-
# state, a mixer model is sufficient.
m.fs.fwh5_da = HelmMixer(
default={
"momentum_mixing_type": MomentumMixingType.none,
"inlet_list": ["steam", "drain", "feedwater"],
"property_package": m.fs.prop_water,
})
@m.fs.fwh5_da.Constraint(m.fs.time)
def mixer_pressure_constraint(b, t):
# Not sure about deaerator pressure, so assume same as feedwater inlet
return b.feedwater_state[t].pressure == b.mixed_state[t].pressure
# Add the boiler feed pump and boiler feed pump turbine
m.fs.bfp = HelmIsentropicCompressor(
default={"property_package": m.fs.prop_water})
m.fs.bfpt = HelmTurbineStage(default={"property_package": m.fs.prop_water})
# The boiler feed pump outlet pressure is the same as the condenser
@m.fs.Constraint(m.fs.time)
def constraint_out_pressure(b, t):
return (b.bfpt.control_volume.properties_out[t].pressure ==
b.condenser.shell.properties_out[t].pressure)
# Instead of specifying a fixed efficiency, specify that the steam is just
# starting to condense at the outlet of the boiler feed pump turbine. This
# ensures approximately the right behavior in the turbine. With a fixed
# efficiency, depending on the conditions you can get odd things like steam
# fully condensing in the turbine.
@m.fs.Constraint(m.fs.time)
def constraint_out_enthalpy(b, t):
return (
b.bfpt.control_volume.properties_out[t].enth_mol ==
b.bfpt.control_volume.properties_out[t].enth_mol_sat_phase["Vap"] -
200 * pyo.units.J / pyo.units.mol)
# The boiler feed pump power is the same as the power generated by the
# boiler feed pump turbine. This constraint determines the steam flow to the
# BFP turbine. The turbine work is negative for power out, while pump work
# is positive for power in.
@m.fs.Constraint(m.fs.time)
def constraint_bfp_power(b, t):
return 0 == b.bfp.control_volume.work[t] + b.bfpt.control_volume.work[t]
############################################################################
# Add high pressure feedwater heaters #
############################################################################
m.fs.fwh6 = FWH0D(
default={
"has_desuperheat": True,
"has_drain_cooling": True,
"has_drain_mixer": True,
"property_package": m.fs.prop_water,
"desuperheat": fwh_config,
"cooling": fwh_config,
"condense": fwh_config,
})
m.fs.fwh7 = FWH0D(
default={
"has_desuperheat": True,
"has_drain_cooling": True,
"has_drain_mixer": True,
"property_package": m.fs.prop_water,
"desuperheat": fwh_config,
"cooling": fwh_config,
"condense": fwh_config,
})
m.fs.fwh8 = FWH0D(
default={
"has_desuperheat": True,
"has_drain_cooling": True,
"has_drain_mixer": False,
"property_package": m.fs.prop_water,
"desuperheat": fwh_config,
"cooling": fwh_config,
"condense": fwh_config,
})
############################################################################
# Additional Constraints/Expressions #
############################################################################
# Add a few constraints to allow a for complete plant results despite the
# lack of a detailed boiler model.
# Boiler pressure drop
m.fs.boiler_pressure_drop_fraction = pyo.Var(
m.fs.time,
initialize=0.01,
doc="Fraction of pressure lost from boiler feed pump and turbine inlet",
)
@m.fs.Constraint(m.fs.time)
def boiler_pressure_drop(b, t):
return (m.fs.bfp.control_volume.properties_out[t].pressure *
(1 - b.boiler_pressure_drop_fraction[t]) ==
m.fs.turb.inlet_split.mixed_state[t].pressure)
# Again, since the boiler is missing, set the flow of steam into the turbine
# equal to the flow of feedwater out of the last feedwater heater.
@m.fs.Constraint(m.fs.time)
def close_flow(b, t):
return (m.fs.bfp.control_volume.properties_out[t].flow_mol ==
m.fs.turb.inlet_split.mixed_state[t].flow_mol)
# Calculate the amount of heat that is added in the boiler, including the
# reheater.
@m.fs.Expression(m.fs.time)
def boiler_heat(b, t):
return (b.turb.inlet_split.mixed_state[t].enth_mol *
b.turb.inlet_split.mixed_state[t].flow_mol -
b.fwh8.desuperheat.tube.properties_out[t].enth_mol *
b.fwh8.desuperheat.tube.properties_out[t].flow_mol +
b.turb.ip_stages[1].control_volume.properties_in[t].enth_mol *
b.turb.ip_stages[1].control_volume.properties_in[t].flow_mol -
b.turb.hp_split[7].outlet_1.enth_mol[t] *
b.turb.hp_split[7].outlet_1.flow_mol[t])
# Calculate the efficiency of the steam cycle. This doesn't account for
# heat loss in the boiler, so actual plant efficiency would be lower.
@m.fs.Expression(m.fs.time)
def steam_cycle_eff(b, t):
return -100 * b.turb.power[t] / b.boiler_heat[t]
############################################################################
## Create the stream Arcs ##
############################################################################
############################################################################
# Connect turbine and condenser units #
############################################################################
m.fs.EXHST_MAIN = Arc(source=m.fs.turb.outlet_stage.outlet,
destination=m.fs.condenser_mix.main)
m.fs.condenser_mix_to_condenser = Arc(source=m.fs.condenser_mix.outlet_tpx,
destination=m.fs.condenser.inlet_1)
m.fs.COND_01 = Arc(source=m.fs.condenser.outlet_1_ph,
destination=m.fs.hotwell.condensate)
m.fs.COND_02 = Arc(source=m.fs.hotwell.outlet,
destination=m.fs.cond_pump.inlet)
############################################################################
# Low pressure FWHs #
############################################################################
m.fs.EXTR_LP11 = Arc(source=m.fs.turb.lp_split[11].outlet_2,
destination=m.fs.fwh1.drain_mix.steam)
m.fs.COND_03 = Arc(source=m.fs.cond_pump.outlet,
destination=m.fs.fwh1.condense.inlet_2)
m.fs.FWH1_DRN1 = Arc(source=m.fs.fwh1.condense.outlet_1,
destination=m.fs.fwh1_pump.inlet)
m.fs.FWH1_DRN2 = Arc(source=m.fs.fwh1_pump.outlet,
destination=m.fs.fwh1_return.fwh1_drain)
m.fs.FW01A = Arc(source=m.fs.fwh1.condense.outlet_2,
destination=m.fs.fwh1_return.feedwater)
# fwh2
m.fs.FW01B = Arc(source=m.fs.fwh1_return.outlet,
destination=m.fs.fwh2.cooling.inlet_2)
m.fs.FWH2_DRN = Arc(source=m.fs.fwh2.cooling.outlet_1,
destination=m.fs.fwh1.drain_mix.drain)
m.fs.EXTR_LP10 = Arc(
source=m.fs.turb.lp_split[10].outlet_2,
destination=m.fs.fwh2.desuperheat.inlet_1,
)
# fwh3
m.fs.FW02 = Arc(source=m.fs.fwh2.desuperheat.outlet_2,
destination=m.fs.fwh3.cooling.inlet_2)
m.fs.FWH3_DRN = Arc(source=m.fs.fwh3.cooling.outlet_1,
destination=m.fs.fwh2.drain_mix.drain)
m.fs.EXTR_LP8 = Arc(source=m.fs.turb.lp_split[8].outlet_2,
destination=m.fs.fwh3.desuperheat.inlet_1)
# fwh4
m.fs.FW03 = Arc(source=m.fs.fwh3.desuperheat.outlet_2,
destination=m.fs.fwh4.cooling.inlet_2)
m.fs.FWH4_DRN = Arc(source=m.fs.fwh4.cooling.outlet_1,
destination=m.fs.fwh3.drain_mix.drain)
m.fs.EXTR_LP4 = Arc(source=m.fs.turb.lp_split[4].outlet_2,
destination=m.fs.fwh4.desuperheat.inlet_1)
############################################################################
# FWH5 (Deaerator) and boiler feed pump (BFP) #
############################################################################
m.fs.FW04 = Arc(source=m.fs.fwh4.desuperheat.outlet_2,
destination=m.fs.fwh5_da.feedwater)
m.fs.EXTR_IP10 = Arc(source=m.fs.turb.ip_split[10].outlet_2,
destination=m.fs.fwh5_da.steam)
m.fs.FW05A = Arc(source=m.fs.fwh5_da.outlet, destination=m.fs.bfp.inlet)
m.fs.EXTR_BFPT_A = Arc(source=m.fs.turb.ip_split[10].outlet_3,
destination=m.fs.bfpt.inlet)
m.fs.EXHST_BFPT = Arc(source=m.fs.bfpt.outlet,
destination=m.fs.condenser_mix.bfpt)
############################################################################
# High-pressure feedwater heaters #
############################################################################
# fwh6
m.fs.FW05B = Arc(source=m.fs.bfp.outlet,
destination=m.fs.fwh6.cooling.inlet_2)
m.fs.FWH6_DRN = Arc(source=m.fs.fwh6.cooling.outlet_1,
destination=m.fs.fwh5_da.drain)
m.fs.EXTR_IP5 = Arc(source=m.fs.turb.ip_split[5].outlet_2,
destination=m.fs.fwh6.desuperheat.inlet_1)
# fwh7
m.fs.FW06 = Arc(source=m.fs.fwh6.desuperheat.outlet_2,
destination=m.fs.fwh7.cooling.inlet_2)
m.fs.FWH7_DRN = Arc(source=m.fs.fwh7.cooling.outlet_1,
destination=m.fs.fwh6.drain_mix.drain)
m.fs.EXTR_HP7 = Arc(source=m.fs.turb.hp_split[7].outlet_2,
destination=m.fs.fwh7.desuperheat.inlet_1)
# fwh8
m.fs.FW07 = Arc(source=m.fs.fwh7.desuperheat.outlet_2,
destination=m.fs.fwh8.cooling.inlet_2)
m.fs.FWH8_DRN = Arc(source=m.fs.fwh8.cooling.outlet_1,
destination=m.fs.fwh7.drain_mix.drain)
m.fs.EXTR_HP4 = Arc(source=m.fs.turb.hp_split[4].outlet_2,
destination=m.fs.fwh8.desuperheat.inlet_1)
############################################################################
# Turn the Arcs into constraints and return the model #
############################################################################
pyo.TransformationFactory("network.expand_arcs").apply_to(m.fs)
return m
def build(self):
super().build()
config = self.config
unit_cfg = { # general unit model config
"dynamic": config.dynamic,
"has_holdup": config.has_holdup,
"property_package": config.property_package,
"property_package_args": config.property_package_args,
}
ni = self.config.num_parallel_inlet_stages
inlet_idx = self.inlet_stage_idx = pyo.RangeSet(ni)
thrtl_cfg = unit_cfg.copy()
thrtl_cfg["valve_function"] = self.config.throttle_valve_function
thrtl_cfg["valve_function_callback"] = \
self.config.throttle_valve_function_callback
# Adding unit models
# ------------------------
# Splitter to inlet that splits main flow into parallel flows for
# paritial arc admission to the turbine
self.inlet_split = HelmSplitter(default=self._split_cfg(unit_cfg, ni))
self.throttle_valve = SteamValve(inlet_idx, default=thrtl_cfg)
self.inlet_stage = HelmTurbineInletStage(inlet_idx, default=unit_cfg)
# mixer to combine the parallel flows back together
self.inlet_mix = HelmMixer(default=self._mix_cfg(unit_cfg, ni))
# add turbine sections.
# inlet stage -> hp stages -> ip stages -> lp stages -> outlet stage
self.hp_stages = HelmTurbineStage(pyo.RangeSet(config.num_hp),
default=unit_cfg)
self.ip_stages = HelmTurbineStage(pyo.RangeSet(config.num_ip),
default=unit_cfg)
self.lp_stages = HelmTurbineStage(pyo.RangeSet(config.num_lp),
default=unit_cfg)
self.outlet_stage = HelmTurbineOutletStage(default=unit_cfg)
for i in self.hp_stages:
self.hp_stages[i].ratioP.fix()
self.hp_stages[i].efficiency_isentropic.fix()
for i in self.ip_stages:
self.ip_stages[i].ratioP.fix()
self.ip_stages[i].efficiency_isentropic.fix()
for i in self.lp_stages:
self.lp_stages[i].ratioP.fix()
self.lp_stages[i].efficiency_isentropic.fix()
# Then make splitter config. If number of outlets is specified
# make a specific config, otherwise use default with 2 outlets
s_sfg_default = self._split_cfg(unit_cfg, 2)
hp_splt_cfg = {}
ip_splt_cfg = {}
lp_splt_cfg = {}
# Now to finish up if there are more than two outlets, set that
for i, v in config.hp_split_num_outlets.items():
hp_splt_cfg[i] = self._split_cfg(unit_cfg, v)
for i, v in config.ip_split_num_outlets.items():
ip_splt_cfg[i] = self._split_cfg(unit_cfg, v)
for i, v in config.lp_split_num_outlets.items():
lp_splt_cfg[i] = self._split_cfg(unit_cfg, v)
# put in splitters for turbine steam extractions
if config.hp_split_locations:
self.hp_split = HelmSplitter(config.hp_split_locations,
default=s_sfg_default,
initialize=hp_splt_cfg)
else:
self.hp_split = {}
if config.ip_split_locations:
self.ip_split = HelmSplitter(config.ip_split_locations,
default=s_sfg_default,
initialize=ip_splt_cfg)
else:
self.ip_split = {}
if config.lp_split_locations:
self.lp_split = HelmSplitter(config.lp_split_locations,
default=s_sfg_default,
initialize=lp_splt_cfg)
else:
self.lp_split = {}
# Done with unit models. Adding Arcs (streams).
# ------------------------------------------------
# First up add streams in the inlet section
def _split_to_rule(b, i):
return {
"source": getattr(self.inlet_split, "outlet_{}".format(i)),
"destination": self.throttle_valve[i].inlet,
}
def _valve_to_rule(b, i):
return {
"source": self.throttle_valve[i].outlet,
"destination": self.inlet_stage[i].inlet,
}
def _inlet_to_rule(b, i):
return {
"source": self.inlet_stage[i].outlet,
"destination": getattr(self.inlet_mix, "inlet_{}".format(i)),
}
self.stream_throttle_inlet = Arc(inlet_idx, rule=_split_to_rule)
self.stream_throttle_outlet = Arc(inlet_idx, rule=_valve_to_rule)
self.stream_inlet_mix_inlet = Arc(inlet_idx, rule=_inlet_to_rule)
# There are three sections HP, IP, and LP which all have the same sort
# of internal connctions, so the functions below provide some generic
# capcbilities for adding the internal Arcs (streams).
def _arc_indexes(nstages, index_set, discon, splits):
"""
This takes the index set of all possible streams in a turbine
section and throws out arc indexes for stages that are disconnected
and arc indexes that are not needed because there is no splitter
after a stage.
Args:
nstages (int): Number of stages in section
index_set (Set): Index set for arcs in the section
discon (list): Disconnected stages in the section
splits (list): Spliter locations
"""
sr = set() # set of things to remove from the Arc index set
for i in index_set:
if (i[0] in discon or i[0] == nstages) and i[0] in splits:
# don't connect stage i to next remove stream after split
sr.add((i[0], 2))
elif (i[0] in discon
or i[0] == nstages) and i[0] not in splits:
# no splitter and disconnect so remove both streams
sr.add((i[0], 1))
sr.add((i[0], 2))
elif i[0] not in splits:
# no splitter and not disconnected so just second stream
sr.add((i[0], 2))
else:
# has splitter so need both streams don't remove anything
pass
for i in sr: # remove the unneeded Arc indexes
index_set.remove(i)
def _arc_rule(turbines, splitters):
"""
This creates a rule function for arcs in a turbine section. When
this is used, the indexes for nonexistant stream will have already
been removed, so any indexes the rule will get should have a stream
associated.
Args:
turbines (TurbineStage): Indexed block with turbine section stages
splitters (Separator): Indexed block of splitters
"""
def _rule(b, i, j):
if i in splitters and j == 1: # stage to splitter
return {
"source": turbines[i].outlet,
"destination": splitters[i].inlet,
}
elif j == 2: # splitter to next stage
return {
"source": splitters[i].outlet_1,
"destination": turbines[i + 1].inlet,
}
else: # no splitter, stage to next stage
return {
"source": turbines[i].outlet,
"destination": turbines[i + 1].inlet,
}
return _rule
# Create initial arcs index sets with all possible streams
self.hp_stream_idx = pyo.Set(initialize=self.hp_stages.index_set() *
[1, 2])
self.ip_stream_idx = pyo.Set(initialize=self.ip_stages.index_set() *
[1, 2])
self.lp_stream_idx = pyo.Set(initialize=self.lp_stages.index_set() *
[1, 2])
# Throw out unneeded streams for disconnected stages or no splitter
_arc_indexes(
config.num_hp,
self.hp_stream_idx,
config.hp_disconnect,
config.hp_split_locations,
)
_arc_indexes(
config.num_ip,
self.ip_stream_idx,
config.ip_disconnect,
config.ip_split_locations,
)
_arc_indexes(
config.num_lp,
self.lp_stream_idx,
config.lp_disconnect,
config.lp_split_locations,
)
# Create connections internal to each turbine section (hp, ip, and lp)
self.hp_stream = Arc(self.hp_stream_idx,
rule=_arc_rule(self.hp_stages, self.hp_split))
self.ip_stream = Arc(self.ip_stream_idx,
rule=_arc_rule(self.ip_stages, self.ip_split))
self.lp_stream = Arc(self.lp_stream_idx,
rule=_arc_rule(self.lp_stages, self.lp_split))
# Connect hp section to ip section unless its a disconnect location
last_hp = config.num_hp
if 0 not in config.ip_disconnect and last_hp not in config.hp_disconnect:
# Not disconnected stage so add stream, depending on splitter existance
if last_hp in config.hp_split_locations: # connect splitter to ip
self.hp_to_ip_stream = Arc(
source=self.hp_split[last_hp].outlet_1,
destination=self.ip_stages[1].inlet,
)
else: # connect last hp to ip
self.hp_to_ip_stream = Arc(
source=self.hp_stages[last_hp].outlet,
destination=self.ip_stages[1].inlet,
)
# Connect ip section to lp section unless its a disconnect location
last_ip = config.num_ip
if 0 not in config.lp_disconnect and last_ip not in config.ip_disconnect:
if last_ip in config.ip_split_locations: # connect splitter to ip
self.ip_to_lp_stream = Arc(
source=self.ip_split[last_ip].outlet_1,
destination=self.lp_stages[1].inlet,
)
else: # connect last hp to ip
self.ip_to_lp_stream = Arc(
source=self.ip_stages[last_ip].outlet,
destination=self.lp_stages[1].inlet,
)
# Connect inlet stage to hp section
# not allowing disconnection of inlet and first regular hp stage
if 0 in config.hp_split_locations:
# connect inlet mix to splitter and splitter to hp section
self.inlet_to_splitter_stream = Arc(
source=self.inlet_mix.outlet,
destination=self.hp_split[0].inlet)
self.splitter_to_hp_stream = Arc(
source=self.hp_split[0].outlet_1,
destination=self.hp_stages[1].inlet)
else: # connect mixer to first hp turbine stage
self.inlet_to_hp_stream = Arc(source=self.inlet_mix.outlet,
destination=self.hp_stages[1].inlet)
self.power = pyo.Var(self.flowsheet().time,
initialize=-1e8,
doc="power (W)")
@self.Constraint(self.flowsheet().time)
def power_eqn(b, t):
return (b.power[t] == b.outlet_stage.control_volume.work[t] *
b.outlet_stage.efficiency_mech +
sum(b.inlet_stage[i].control_volume.work[t] *
b.inlet_stage[i].efficiency_mech
for i in b.inlet_stage) +
sum(b.hp_stages[i].control_volume.work[t] *
b.hp_stages[i].efficiency_mech for i in b.hp_stages) +
sum(b.ip_stages[i].control_volume.work[t] *
b.ip_stages[i].efficiency_mech for i in b.ip_stages) +
sum(b.lp_stages[i].control_volume.work[t] *
b.lp_stages[i].efficiency_mech for i in b.lp_stages))
# Connect lp section to outlet stage, not allowing outlet stage to be
# disconnected
last_lp = config.num_lp
if last_lp in config.lp_split_locations: # connect splitter to outlet
self.lp_to_outlet_stream = Arc(
source=self.lp_split[last_lp].outlet_1,
destination=self.outlet_stage.inlet,
)
else: # connect last lpstage to outlet
self.lp_to_outlet_stream = Arc(
source=self.lp_stages[last_lp].outlet,
destination=self.outlet_stage.inlet,
)
pyo.TransformationFactory("network.expand_arcs").apply_to(self)
def add_unit_models(m):
fs = m.fs_main.fs_blr
prop_water = m.fs_main.prop_water
prop_gas = m.fs_main.prop_gas
fs.num_mills = pyo.Var()
fs.num_mills.fix(4)
# 14 waterwall zones
fs.ww_zones = pyo.RangeSet(14)
# boiler based on surrogate
fs.aBoiler = BoilerSurrogate(default={"dynamic": False,
"side_1_property_package": prop_gas,
"side_2_property_package": prop_gas,
"has_heat_transfer": False,
"has_pressure_change": False,
"has_holdup": False})
# model a drum by a WaterFlash, a Mixer and a Drum model
fs.aFlash = WaterFlash(default={"dynamic": False,
"property_package": prop_water,
"has_phase_equilibrium": False,
"has_heat_transfer": False,
"has_pressure_change": False})
fs.aMixer = HelmMixer(default={"dynamic": False,
"property_package": prop_water,
"momentum_mixing_type": MomentumMixingType.equality,
"inlet_list": ["FeedWater", "SatWater"]})
fs.aDrum = Drum1D(default={"property_package": prop_water,
"has_holdup": True,
"has_heat_transfer": True,
"has_pressure_change": True,
"finite_elements": 4,
"inside_diameter": 1.778,
"thickness": 0.127})
fs.blowdown_split = HelmSplitter(
default={
"dynamic": False,
"property_package": prop_water,
"outlet_list": ["FW_Downcomer", "FW_Blowdown"],
}
)
# downcomer
fs.aDowncomer = Downcomer(default={
"dynamic": False,
"property_package": prop_water,
"has_holdup": True,
"has_heat_transfer": True,
"has_pressure_change": True})
# 14 WaterwallSection units
fs.Waterwalls = WaterwallSection(fs.ww_zones,
default={
"has_holdup": True,
"property_package": prop_water,
"has_equilibrium_reactions": False,
"has_heat_of_reaction": False,
"has_heat_transfer": True,
"has_pressure_change": True})
# roof superheater
fs.aRoof = SteamHeater(default={
"dynamic": False,
"property_package": prop_water,
"has_holdup": True,
"has_equilibrium_reactions": False,
"has_heat_of_reaction": False,
"has_heat_transfer": True,
"has_pressure_change": True,
"single_side_only" : True})
# platen superheater
fs.aPlaten = SteamHeater(default={
"dynamic": False,
"property_package": prop_water,
"has_holdup": True,
"has_equilibrium_reactions": False,
"has_heat_of_reaction": False,
"has_heat_transfer": True,
"has_pressure_change": True,
"single_side_only" : False})
# 1st reheater
fs.aRH1 = HeatExchangerCrossFlow2D(default={
"tube_side":{"property_package": prop_water, "has_holdup": False,
"has_pressure_change": True},
"shell_side":{"property_package": prop_gas, "has_holdup": False,
"has_pressure_change": True},
"finite_elements": 4,
"flow_type": "counter_current",
"tube_arrangement": "in-line",
"tube_side_water_phase": "Vap",
"has_radiation": True,
"radial_elements": 5,
"inside_diameter": 2.202*0.0254,
"thickness": 0.149*0.0254})
# 2nd reheater
fs.aRH2 = HeatExchangerCrossFlow2D(default={
"tube_side":{"property_package": prop_water, "has_holdup": False,
"has_pressure_change": True},
"shell_side":{"property_package": prop_gas, "has_holdup": False,
"has_pressure_change": True},
"finite_elements": 2,
"flow_type": "counter_current",
"tube_arrangement": "in-line",
"tube_side_water_phase": "Vap",
"has_radiation": True,
"radial_elements": 5,
"inside_diameter": 2.217*0.0254,
"thickness": 0.1415*0.0254})
# primary superheater
fs.aPSH = HeatExchangerCrossFlow2D(default={
"tube_side":{"property_package": prop_water, "has_holdup": False,
"has_pressure_change": True},
"shell_side":{"property_package": prop_gas, "has_holdup": False,
"has_pressure_change": True},
"finite_elements": 5,
"flow_type": "counter_current",
"tube_arrangement": "in-line",
"tube_side_water_phase": "Vap",
"has_radiation": True,
"radial_elements": 5,
"inside_diameter": 1.45*0.0254,
"thickness": 0.15*0.0254})
# economizer
fs.aECON = HeatExchangerCrossFlow2D(default={
"tube_side":{"property_package": prop_water, "has_holdup": False,
"has_pressure_change": True},
"shell_side":{"property_package": prop_gas, "has_holdup": False,
"has_pressure_change": True},
"finite_elements": 5,
"flow_type": "counter_current",
"tube_arrangement": "in-line",
"tube_side_water_phase": "Liq",
"has_radiation": False,
"radial_elements": 5,
"inside_diameter": 1.452*0.0254,
"thickness": 0.149*0.0254})
# water pipe from economizer outlet to drum
fs.aPipe = WaterPipe(default={
"dynamic": False,
"property_package": prop_water,
"has_holdup": True,
"has_heat_transfer": False,
"has_pressure_change": True,
"water_phase": 'Liq',
"contraction_expansion_at_end": 'None'})
# a mixer to mix hot primary air with tempering air
fs.Mixer_PA = Mixer(
default={
"dynamic": False,
"property_package": prop_gas,
"momentum_mixing_type": MomentumMixingType.equality,
"inlet_list": ["PA_inlet", "TA_inlet"],
}
)
# attemperator for main steam before platen SH
fs.Attemp = HelmMixer(
default={
"dynamic": False,
"property_package": prop_water,
"momentum_mixing_type": MomentumMixingType.equality,
"inlet_list": ["Steam_inlet", "Water_inlet"],
}
)
# air preheater as three-stream heat exchanger with heat loss to ambient,
# side_1: flue gas
# side_2:PA (priamry air?)
# side_3:PA (priamry air?)
fs.aAPH = HeatExchangerWith3Streams(
default={"dynamic": False,
"side_1_property_package": prop_gas,
"side_2_property_package": prop_gas,
"side_3_property_package": prop_gas,
"has_heat_transfer": True,
"has_pressure_change": True,
"has_holdup": False,
"flow_type_side_2": "counter-current",
"flow_type_side_3": "counter-current",
}
)
return m