fix MVC single stage

watertap/examples/flowsheets/mvc/mvc_single_stage.py

@@ -457,7 +457,7 @@ def initialize_system(m, solver=None):
 
     # initialize feed pump
     propagate_state(m.fs.s01)
-    m.fs.pump_feed.initialize(optarg=optarg)
+    m.fs.pump_feed.initialize(optarg=optarg, solver="ipopt-watertap")
 
     # initialize separator
     propagate_state(m.fs.s02)
@@ -466,11 +466,11 @@ def initialize_system(m, solver=None):
     m.fs.separator_feed.split_fraction[0, "hx_distillate_cold"].fix(
         m.fs.recovery[0].value
     )
-    m.fs.separator_feed.mixed_state.initialize(optarg=optarg)
+    m.fs.separator_feed.mixed_state.initialize(optarg=optarg, solver="ipopt-watertap")
     # Touch properties for initialization
     m.fs.separator_feed.hx_brine_cold_state[0].mass_frac_phase_comp["Liq", "TDS"]
     m.fs.separator_feed.hx_distillate_cold_state[0].mass_frac_phase_comp["Liq", "TDS"]
-    m.fs.separator_feed.initialize(optarg=optarg)
+    m.fs.separator_feed.initialize(optarg=optarg, solver="ipopt-watertap")
     m.fs.separator_feed.split_fraction[0, "hx_distillate_cold"].unfix()
 
     # initialize distillate heat exchanger
@@ -489,7 +489,7 @@ def initialize_system(m, solver=None):
         m.fs.evaporator.outlet_brine.temperature[0].value
     )
     m.fs.hx_distillate.hot_inlet.pressure[0] = 101325
-    m.fs.hx_distillate.initialize()
+    m.fs.hx_distillate.initialize(solver="ipopt-watertap")
 
     # initialize brine heat exchanger
     propagate_state(m.fs.s04)
@@ -507,34 +507,36 @@ def initialize_system(m, solver=None):
         0
     ].value
     m.fs.hx_brine.hot_inlet.pressure[0] = 101325
-    m.fs.hx_brine.initialize()
+    m.fs.hx_brine.initialize(solver="ipopt-watertap")
 
     # initialize mixer
     propagate_state(m.fs.s05)
     propagate_state(m.fs.s06)
-    m.fs.mixer_feed.initialize()
+    m.fs.mixer_feed.initialize(solver="ipopt-watertap")
     m.fs.mixer_feed.pressure_equality_constraints[0, 2].deactivate()
 
     # initialize evaporator
     propagate_state(m.fs.s07)
     m.fs.Q_ext[0].fix()
     m.fs.evaporator.properties_vapor[0].flow_mass_phase_comp["Vap", "H2O"].fix()
     # fixes and unfixes those values
-    m.fs.evaporator.initialize(delta_temperature_in=60)
+    m.fs.evaporator.initialize(delta_temperature_in=60, solver="ipopt-watertap")
     m.fs.Q_ext[0].unfix()
     m.fs.evaporator.properties_vapor[0].flow_mass_phase_comp["Vap", "H2O"].unfix()
 
     # initialize compressor
     propagate_state(m.fs.s08)
-    m.fs.compressor.initialize()
+    m.fs.compressor.initialize(solver="ipopt-watertap")
 
     # initialize condenser
     propagate_state(m.fs.s09)
-    m.fs.condenser.initialize(heat=-m.fs.evaporator.heat_transfer.value)
+    m.fs.condenser.initialize(
+        heat=-m.fs.evaporator.heat_transfer.value, solver="ipopt-watertap"
+    )
 
     # initialize brine pump
     propagate_state(m.fs.s10)
-    m.fs.pump_brine.initialize(optarg=optarg)
+    m.fs.pump_brine.initialize(optarg=optarg, solver="ipopt-watertap")
 
     # initialize distillate pump
     propagate_state(m.fs.s13)  # to translator block
@@ -545,7 +547,7 @@ def initialize_system(m, solver=None):
     m.fs.pump_distillate.control_volume.properties_in[0].pressure = (
         m.fs.condenser.control_volume.properties_out[0].pressure.value
     )
-    m.fs.pump_distillate.initialize(optarg=optarg)
+    m.fs.pump_distillate.initialize(optarg=optarg, solver="ipopt-watertap")
 
     # propagate brine state
     propagate_state(m.fs.s12)
@@ -562,24 +564,25 @@ def func_initialize(unit):
             unit.initialize(
                 heat=-unit.flowsheet().evaporator.heat_transfer.value,
                 optarg=solver.options,
+                solver="ipopt-watertap",
             )
         elif unit.local_name == "evaporator":
             unit.flowsheet().Q_ext[0].fix()
             unit.properties_vapor[0].flow_mass_phase_comp["Vap", "H2O"].fix()
-            unit.initialize(delta_temperature_in=60)
+            unit.initialize(delta_temperature_in=60, solver="ipopt-watertap")
             unit.flowsheet().Q_ext[0].unfix()
             unit.properties_vapor[0].flow_mass_phase_comp["Vap", "H2O"].unfix()
         elif unit.local_name == "separator_feed":
             unit.split_fraction[0, "hx_distillate_cold"].fix(
                 unit.flowsheet().recovery[0].value
             )
-            unit.initialize()
+            unit.initialize(solver="ipopt-watertap")
             unit.split_fraction[0, "hx_distillate_cold"].unfix()
         elif unit.local_name == "mixer_feed":
-            unit.initialize()
+            unit.initialize(solver="ipopt-watertap")
             unit.pressure_equality_constraints[0, 2].deactivate()
         else:
-            unit.initialize()
+            unit.initialize(solver="ipopt-watertap")
 
     seq.run(m, func_initialize)