def test_tear_selection(self):
m = self.simple_recycle_model()
seq = SequentialDecomposition()
G = seq.create_graph(m)
heu_result = seq.select_tear_heuristic(G)
self.assertEqual(heu_result[1], 1)
self.assertEqual(heu_result[2], 1)
all_tsets = []
for tset in heu_result[0]:
all_tsets.append(seq.indexes_to_arcs(G, tset))
for arc in (m.stream_mixer_to_unit, m.stream_unit_to_splitter,
m.stream_splitter_to_mixer):
self.assertIn([arc], all_tsets)
tset_mip = seq.tear_set_arcs(G, "mip", solver="gams")
self.assertIn(tset_mip, all_tsets)
tset_heu = seq.tear_set_arcs(G, "heuristic")
self.assertIn(tset_heu, all_tsets)
def main():
# Create a Concrete Model as the top level object
m = ConcreteModel()
# Add a flowsheet object to the model
m.fs = FlowsheetBlock(default={"dynamic": False})
# Add property packages to flowsheet library
m.fs.thermo_params = thermo_props.HDAParameterBlock()
m.fs.reaction_params = reaction_props.HDAReactionParameterBlock(
default={"property_package": m.fs.thermo_params})
# Create unit models
m.fs.M101 = Mixer(
default={
"property_package": m.fs.thermo_params,
"inlet_list": ["toluene_feed", "hydrogen_feed", "vapor_recycle"]
})
m.fs.H101 = Heater(
default={
"property_package": m.fs.thermo_params,
"has_pressure_change": False,
"has_phase_equilibrium": True
})
m.fs.R101 = StoichiometricReactor(
default={
"property_package": m.fs.thermo_params,
"reaction_package": m.fs.reaction_params,
"has_heat_of_reaction": True,
"has_heat_transfer": True,
"has_pressure_change": False
})
m.fs.F101 = Flash(
default={
"property_package": m.fs.thermo_params,
"has_heat_transfer": True,
"has_pressure_change": True
})
m.fs.S101 = Splitter(
default={
"property_package": m.fs.thermo_params,
"ideal_separation": False,
"outlet_list": ["purge", "recycle"]
})
# This is needed to avoid pressure degeneracy in recylce loop
m.fs.C101 = PressureChanger(
default={
"property_package": m.fs.thermo_params,
"compressor": True,
"thermodynamic_assumption": ThermodynamicAssumption.isothermal
})
m.fs.F102 = Flash(
default={
"property_package": m.fs.thermo_params,
"has_heat_transfer": True,
"has_pressure_change": True
})
m.fs.H101.control_volume.scaling_factor_energy = 1e-3
m.fs.R101.control_volume.scaling_factor_energy = 1e-3
m.fs.F101.control_volume.scaling_factor_energy = 1e-3
m.fs.C101.control_volume.scaling_factor_energy = 1e-3
m.fs.F102.control_volume.scaling_factor_energy = 1e-3
# Connect units
m.fs.s03 = Arc(source=m.fs.M101.outlet, destination=m.fs.H101.inlet)
m.fs.s04 = Arc(source=m.fs.H101.outlet, destination=m.fs.R101.inlet)
m.fs.s05 = Arc(source=m.fs.R101.outlet, destination=m.fs.F101.inlet)
m.fs.s06 = Arc(source=m.fs.F101.vap_outlet, destination=m.fs.S101.inlet)
m.fs.s08 = Arc(source=m.fs.S101.recycle, destination=m.fs.C101.inlet)
m.fs.s09 = Arc(source=m.fs.C101.outlet,
destination=m.fs.M101.vapor_recycle)
m.fs.s10 = Arc(source=m.fs.F101.liq_outlet, destination=m.fs.F102.inlet)
TransformationFactory("network.expand_arcs").apply_to(m)
# Set operating conditions
m.fs.M101.toluene_feed.flow_mol_phase_comp[0, "Vap", "benzene"].fix(1e-5)
m.fs.M101.toluene_feed.flow_mol_phase_comp[0, "Vap", "toluene"].fix(1e-5)
m.fs.M101.toluene_feed.flow_mol_phase_comp[0, "Vap", "hydrogen"].fix(1e-5)
m.fs.M101.toluene_feed.flow_mol_phase_comp[0, "Vap", "methane"].fix(1e-5)
m.fs.M101.toluene_feed.flow_mol_phase_comp[0, "Liq", "benzene"].fix(1e-5)
m.fs.M101.toluene_feed.flow_mol_phase_comp[0, "Liq", "toluene"].fix(0.30)
m.fs.M101.toluene_feed.flow_mol_phase_comp[0, "Liq", "hydrogen"].fix(1e-5)
m.fs.M101.toluene_feed.flow_mol_phase_comp[0, "Liq", "methane"].fix(1e-5)
m.fs.M101.toluene_feed.temperature.fix(303.2)
m.fs.M101.toluene_feed.pressure.fix(350000)
m.fs.M101.hydrogen_feed.flow_mol_phase_comp[0, "Vap", "benzene"].fix(1e-5)
m.fs.M101.hydrogen_feed.flow_mol_phase_comp[0, "Vap", "toluene"].fix(1e-5)
m.fs.M101.hydrogen_feed.flow_mol_phase_comp[0, "Vap", "hydrogen"].fix(0.30)
m.fs.M101.hydrogen_feed.flow_mol_phase_comp[0, "Vap", "methane"].fix(0.02)
m.fs.M101.hydrogen_feed.flow_mol_phase_comp[0, "Liq", "benzene"].fix(1e-5)
m.fs.M101.hydrogen_feed.flow_mol_phase_comp[0, "Liq", "toluene"].fix(1e-5)
m.fs.M101.hydrogen_feed.flow_mol_phase_comp[0, "Liq", "hydrogen"].fix(1e-5)
m.fs.M101.hydrogen_feed.flow_mol_phase_comp[0, "Liq", "methane"].fix(1e-5)
m.fs.M101.hydrogen_feed.temperature.fix(303.2)
m.fs.M101.hydrogen_feed.pressure.fix(350000)
m.fs.H101.outlet.temperature.fix(600)
m.fs.R101.conversion = Var(initialize=0.75, bounds=(0, 1))
m.fs.R101.conv_constraint = Constraint(
expr=m.fs.R101.conversion *
m.fs.R101.inlet.flow_mol_phase_comp[0, "Vap", "toluene"] == (
m.fs.R101.inlet.flow_mol_phase_comp[0, "Vap", "toluene"] -
m.fs.R101.outlet.flow_mol_phase_comp[0, "Vap", "toluene"]))
m.fs.R101.conversion.fix(0.75)
m.fs.R101.heat_duty.fix(0)
m.fs.F101.vap_outlet.temperature.fix(325.0)
m.fs.F101.deltaP.fix(0)
m.fs.S101.split_fraction[0, "purge"].fix(0.2)
m.fs.C101.outlet.pressure.fix(350000)
m.fs.F102.vap_outlet.temperature.fix(375)
m.fs.F102.deltaP.fix(-200000)
# Define expressions
# Product purity
m.fs.purity = Expression(
expr=m.fs.F102.vap_outlet.flow_mol_phase_comp[0, "Vap", "benzene"] /
(m.fs.F102.vap_outlet.flow_mol_phase_comp[0, "Vap", "benzene"] +
m.fs.F102.vap_outlet.flow_mol_phase_comp[0, "Vap", "toluene"]))
# Operating cost ($/yr)
m.fs.cooling_cost = Expression(expr=0.212e-7 * -m.fs.F101.heat_duty[0] +
0.212e-7 * -m.fs.R101.heat_duty[0])
m.fs.heating_cost = Expression(expr=2.2e-7 * m.fs.H101.heat_duty[0] +
1.9e-7 * m.fs.F102.heat_duty[0])
m.fs.operating_cost = Expression(
expr=(3600 * 24 * 365 * (m.fs.heating_cost + m.fs.cooling_cost)))
print(degrees_of_freedom(m))
# Initialize Units
# Define method for initialising each block
def function(unit):
unit.initialize(outlvl=1)
# Create instance of sequential decomposition tool
seq = SequentialDecomposition()
seq.options.select_tear_method = "heuristic"
seq.options.tear_method = "Wegstein"
seq.options.iterLim = 5
# Determine tear stream and calculation order
G = seq.create_graph(m)
heu_result = seq.tear_set_arcs(G, method="heuristic")
order = seq.calculation_order(G)
# Display tear stream and calculation order
for o in heu_result:
print(o.name)
for o in order:
for oo in o:
print(oo.name)
# Set guesses for tear stream
tear_guesses = {
"flow_mol_phase_comp": {
(0, "Vap", "benzene"): 1e-5,
(0, "Vap", "toluene"): 1e-5,
(0, "Vap", "hydrogen"): 0.30,
(0, "Vap", "methane"): 0.02,
(0, "Liq", "benzene"): 1e-5,
(0, "Liq", "toluene"): 0.30,
(0, "Liq", "hydrogen"): 1e-5,
(0, "Liq", "methane"): 1e-5
},
"temperature": {
0: 303
},
"pressure": {
0: 350000
}
}
seq.set_guesses_for(m.fs.H101.inlet, tear_guesses)
# Run sequential initialization
seq.run(m, function)
# # Create a solver
solver = SolverFactory('ipopt')
solver.options = {'tol': 1e-6}
solver.options = {'tol': 1e-6, 'max_iter': 5000}
results = solver.solve(m, tee=True)
# Print results
print("M101 Outlet")
m.fs.M101.outlet.display()
print("H101 Outlet")
m.fs.H101.outlet.display()
print("R101 Outlet")
m.fs.R101.outlet.display()
print("F101")
m.fs.F101.liq_outlet.display()
m.fs.F101.vap_outlet.display()
print("F102")
m.fs.F102.liq_outlet.display()
m.fs.F102.vap_outlet.display()
print("Purge")
m.fs.S101.purge.display()
print("Purity:", value(m.fs.purity))
# Optimize process
m.fs.objective = Objective(sense=minimize, expr=m.fs.operating_cost)
# Decision variables
m.fs.H101.outlet.temperature.unfix()
m.fs.R101.heat_duty.unfix()
m.fs.F101.vap_outlet.temperature.unfix()
m.fs.F102.vap_outlet.temperature.unfix()
m.fs.F102.deltaP.unfix()
# Variable bounds
m.fs.H101.outlet.temperature[0].setlb(500)
m.fs.H101.outlet.temperature[0].setub(600)
m.fs.R101.outlet.temperature[0].setlb(600)
m.fs.R101.outlet.temperature[0].setub(800)
m.fs.F101.vap_outlet.temperature[0].setlb(298.0)
m.fs.F101.vap_outlet.temperature[0].setub(450.0)
m.fs.F102.vap_outlet.temperature[0].setlb(298.0)
m.fs.F102.vap_outlet.temperature[0].setub(450.0)
m.fs.F102.vap_outlet.pressure[0].setlb(105000)
m.fs.F102.vap_outlet.pressure[0].setub(110000)
# Additional Constraints
m.fs.overhead_loss = Constraint(
expr=m.fs.F101.vap_outlet.flow_mol_phase_comp[0, "Vap",
"benzene"] <= 0.20 *
m.fs.R101.outlet.flow_mol_phase_comp[0, "Vap", "benzene"])
m.fs.product_flow = Constraint(
expr=m.fs.F102.vap_outlet.flow_mol_phase_comp[0, "Vap",
"benzene"] >= 0.15)
m.fs.product_purity = Constraint(expr=m.fs.purity >= 0.80)
# Create a solver
solver = SolverFactory('ipopt')
solver.options = {'tol': 1e-6}
solver.options = {'tol': 1e-6, 'max_iter': 5000}
results = solver.solve(m, tee=True)
# Print optimization results
print()
print("Optimal Solution")
m.fs.operating_cost.display()
m.fs.H101.heat_duty.display()
m.fs.R101.heat_duty.display()
m.fs.F101.heat_duty.display()
m.fs.F102.heat_duty.display()
# Print results
print("M101 Outlet")
m.fs.M101.outlet.display()
print("H101 Outlet")
m.fs.H101.outlet.display()
print("R101 Outlet")
m.fs.R101.outlet.display()
print("F101")
m.fs.F101.liq_outlet.display()
m.fs.F101.vap_outlet.display()
print("F102")
m.fs.F102.liq_outlet.display()
m.fs.F102.vap_outlet.display()
print("Purge")
m.fs.S101.purge.display()
print("Recycle")
m.fs.S101.recycle.display()
print("Purity:", value(m.fs.purity))
# For testing purposes
return (m, results)