Double Inlet - Single Outlet Helper Methods

The build_diso method is intended to be used to rapidly construct a standard set of material balance equations for zero-order type models with a double inlet and single outlet.

Usage

from idaes.core import declare_process_block_class
from watertap.core import build_diso, ZeroOrderBaseData

@declare_process_block_class("CofermentationZO")
class CofermentationZOData(ZeroOrderBaseData):

    CONFIG = ZeroOrderBaseData.CONFIG()

    def build(self):
        super().build()

        self._tech_type = "cofermentation"

        build_diso(self)

Model Structure

The build_diso method constructs a simple representation of unit operation with two inlets (named inlet1 and inlet2) and one outlet (named treated). A StateBlock is constructed for each inlet and outlet with a Port associated with each of these.

Variables

The build_diso method creates the following variables in addition to those created by the StateBlocks.

Variable	Name	Indices	Notes
\(r_{t}\)	recovery_frac_mass_H2O	time	Fraction of mass flow of water in inlet that goes to treated stream.
\(f_{t,j}\)	removal_frac_mass_solute	time, solutes	Fraction of mass flow of each solute that is removed from the inlet stream.

recovery_frac_mass_H2O is intended to be fixed to zero (e.g., for reactor that yields solid product at treated outlet) or 1 (e.g., for reactor that yields product stream without water losses), but the user can optionally set this to some fraction.

Constraints

The build_diso method writes the following constraints which relate the inlet states to those in the treated outlet stream. First, a water recovery equation is written for water to relate the flowrate at the treated outlet to that at the inlet:

water_recovery_equation(t):

\[r_t \times (M_{inlet1,t,H2O} + M_{inlet2,t,H2O}) = M_{treated,t,H2O}\]

where \(M_{t,H2O}\) is mass flowrate of water at time \(t\).

Note, a mass balance for water is ignored since build_diso is intended to only account for constituent removal/conversion at the treated outlet. Thus, a mass balance constraint is only written for each solute.

solute_treated_equation(t, j):

\[(1 - f_{t, j}) \times (M_{inlet1,t,j} + M_{inlet2,t,j}) = M_{treated,t,j}\]

Module Documentation

Helper method for constructing material balances for zero-order type models with DISO behavior.

Three StateBlocks are added with two corresponding Ports:

• properties_in1 –> inlet1

• properties_in2 –> inlet2

• properties_treated —> treated

Two additional variables are added:

• recovery_frac_mass_H2O (indexed by time)

• removal_frac_mass_solute (indexed by time and solute)

Two additional constraints are added to represent the material balances

• water_recovery_equation (indexed by time)

• solute_treated_equation (indexed by time and solute)

This method also sets private attributes on the unit model with references to the appropriate initialization and scaling methods to use and to return the inlet volumetric flow rate.