Adding attributes to hold units used by MSContactor (#1396)

* Adding attributes to hold units used by MSContactor

* Removing unneccessary argument and fixing tests

idaes/models/unit_models/mscontactor.py

@@ -385,17 +385,21 @@ def build(self):
         # Call UnitModel.build
         super().build()
 
+        # Placeholders for things we will get from first StateBlock
+        self.flow_basis = None
+        self.uom = None
+
         self._verify_inputs()
-        flow_basis, uom = self._build_state_blocks()
+        self._build_state_blocks()
 
         if self.config.heterogeneous_reactions is not None:
             self._build_heterogeneous_reaction_blocks()
 
-        self._add_geometry(uom)
+        self._add_geometry()
 
-        self._build_material_balance_constraints(flow_basis, uom)
-        self._build_energy_balance_constraints(uom)
-        self._build_pressure_balance_constraints(uom)
+        self._build_material_balance_constraints()
+        self._build_energy_balance_constraints()
+        self._build_pressure_balance_constraints()
         self._build_ports()
 
     def _verify_inputs(self):
@@ -461,10 +465,6 @@ def _verify_inputs(self):
 
     def _build_state_blocks(self):
         # Build state blocks
-        # Placeholders for things we will get from first StateBlock
-        flow_basis = None
-        uom = None
-
         for stream, pconfig in self.config.streams.items():
             ppack = pconfig.property_package
 
@@ -514,19 +514,19 @@ def _build_state_blocks(self):
 
             tref = self.flowsheet().time.first()
             sref = self.elements.first()
-            if flow_basis is None:
+            if self.flow_basis is None:
                 # Set unit level flow basis and units from first stream
 
-                flow_basis = state[tref, sref].get_material_flow_basis()
-                uom = state[tref, sref].params.get_metadata().derived_units
+                self.flow_basis = state[tref, sref].get_material_flow_basis()
+                self.uom = state[tref, sref].params.get_metadata().derived_units
             else:
                 # Check that flow bases are consistent
-                if not state[tref, sref].get_material_flow_basis() == flow_basis:
+                if not state[tref, sref].get_material_flow_basis() == self.flow_basis:
                     raise ConfigurationError(
                         f"Property packages use different flow bases: ExtractionCascade "
                         f"requires all property packages to use the same basis. "
                         f"{stream} uses {state[tref, sref].get_material_flow_basis()}, "
-                        f"whilst first stream uses {flow_basis}."
+                        f"whilst first stream uses {self.flow_basis}."
                     )
 
             # Build reactions blocks if provided
@@ -543,8 +543,6 @@ def _build_state_blocks(self):
                 )
                 self.add_component(stream + "_reactions", reactions)
 
-        return flow_basis, uom
-
     def _build_heterogeneous_reaction_blocks(self):
         rpack = self.config.heterogeneous_reactions
         rpack_args = self.config.heterogeneous_reactions_args
@@ -569,14 +567,14 @@ def _build_heterogeneous_reaction_blocks(self):
                 "reactions (reaction_idx)."
             )
 
-    def _add_geometry(self, uom):
+    def _add_geometry(self):
         if self.config.has_holdup:
             # Add volume for each element
             # TODO: Assuming constant volume for now
             self.volume = Var(
                 self.elements,
                 initialize=1,
-                units=uom.VOLUME,
+                units=self.uom.VOLUME,
                 doc="Volume of element",
             )
             self.volume_frac_stream = Var(
@@ -600,14 +598,14 @@ def sum_volume_frac(b, t, e):
                 phase_list = getattr(self, stream).phase_list
                 _add_phase_fractions(self, stream, phase_list)
 
-    def _build_material_balance_constraints(self, flow_basis, uom):
+    def _build_material_balance_constraints(self):
         # Get units for transfer terms
-        if flow_basis is MaterialFlowBasis.molar:
-            mb_units = uom.FLOW_MOLE
-            hu_units = uom.AMOUNT
-        elif flow_basis is MaterialFlowBasis.mass:
-            mb_units = uom.FLOW_MASS
-            hu_units = uom.MASS
+        if self.flow_basis is MaterialFlowBasis.molar:
+            mb_units = self.uom.FLOW_MOLE
+            hu_units = self.uom.AMOUNT
+        elif self.flow_basis is MaterialFlowBasis.mass:
+            mb_units = self.uom.FLOW_MASS
+            hu_units = self.uom.MASS
         else:
             # Flow type other, so cannot determine units
             mb_units = None
@@ -895,9 +893,8 @@ def _build_material_balance_constraints(self, flow_basis, uom):
             )
             self.add_component(stream + "_material_balance", mbal)
 
-    def _build_energy_balance_constraints(self, uom):
+    def _build_energy_balance_constraints(self):
         # Energy Balances
-
         for stream, pconfig in self.config.streams.items():
             if pconfig.has_energy_balance:
                 state_block = getattr(self, stream)
@@ -912,7 +909,7 @@ def _build_energy_balance_constraints(self, uom):
                         domain=Reals,
                         initialize=1.0,
                         doc="Energy holdup of stream in element",
-                        units=uom.ENERGY,
+                        units=self.uom.ENERGY,
                     )
                     self.add_component(
                         stream + "_energy_holdup",
@@ -939,7 +936,7 @@ def _build_energy_balance_constraints(self, uom):
                         energy_holdup,
                         wrt=self.flowsheet().time,
                         doc="Energy accumulation for in element",
-                        units=uom.POWER,
+                        units=self.uom.POWER,
                     )
                     self.add_component(
                         stream + "_energy_accumulation",
@@ -951,7 +948,7 @@ def _build_energy_balance_constraints(self, uom):
                         self.flowsheet().time,
                         self.elements,
                         initialize=0,
-                        units=uom.POWER,
+                        units=self.uom.POWER,
                         doc=f"External heat transfer term for stream {stream}",
                     )
                     self.add_component(stream + "_heat", heat)
@@ -962,12 +959,12 @@ def _build_energy_balance_constraints(self, uom):
                     rule=partial(
                         _energy_balance_rule,
                         stream=stream,
-                        uom=uom,
+                        uom=self.uom,
                     ),
                 )
                 self.add_component(stream + "_energy_balance", ebal)
 
-    def _build_pressure_balance_constraints(self, uom):
+    def _build_pressure_balance_constraints(self):
         # Pressure Balances
         for stream, pconfig in self.config.streams.items():
             if pconfig.has_pressure_balance:
@@ -977,7 +974,7 @@ def _build_pressure_balance_constraints(self, uom):
                         self.flowsheet().time,
                         self.elements,
                         initialize=0,
-                        units=uom.PRESSURE,
+                        units=self.uom.PRESSURE,
                         doc=f"DeltaP term for stream {stream}",
                     )
                     self.add_component(stream + "_deltaP", deltaP)
@@ -988,7 +985,7 @@ def _build_pressure_balance_constraints(self, uom):
                     rule=partial(
                         _pressure_balance_rule,
                         stream=stream,
-                        uom=uom,
+                        uom=self.uom,
                     ),
                 )
                 self.add_component(stream + "_pressure_balance", pbal)