How to run a zero-order model
The example script shown below is for the dual media filtration zero-order model. This example uses the default parameters defined in the watertap YAML database.
from pyomo.environ import ConcreteModel
from idaes.core import FlowsheetBlock
from watertap.core.solvers import get_solver
from watertap.core.wt_database import Database
from watertap.core.zero_order_properties import WaterParameterBlock
from watertap.unit_models.zero_order import DualMediaFiltrationZO
def main():
# Create a Pyomo model and initialize the YAML database
model = ConcreteModel()
model.db = Database()
# Create an IDAES flowsheet and define the solutes
model.fs = FlowsheetBlock(dynamic=False)
model.fs.params = WaterParameterBlock(solute_list=["nonvolatile_toc", "toc", "tss"])
# Setup the zero-order model and define inlet flows
model.fs.unit = DualMediaFiltrationZO(property_package=model.fs.params, database=model.db)
model.fs.unit.inlet.flow_mass_comp[0, "H2O"].fix(10)
model.fs.unit.inlet.flow_mass_comp[0, "nonvolatile_toc"].fix(1)
model.fs.unit.inlet.flow_mass_comp[0, "toc"].fix(1)
model.fs.unit.inlet.flow_mass_comp[0, "tss"].fix(1)
# Load default parameters from the YAML database
model.fs.unit.load_parameters_from_database()
# Access the solver and solve the model
solver = get_solver()
solver.solve(model)
# Display a report of the results
model.fs.unit.report()
if __name__ == "__main__":
main()
The output from running the example is shown below.
====================================================================================
Unit : fs.unit Time: 0.0
------------------------------------------------------------------------------------
Unit Performance
Variables:
Key : Value : Units : Fixed : Bounds
Electricity Demand : 2373.6 : watt : False : (0, None)
Electricity Intensity : 1.8259e+05 : pascal : True : (None, None)
Solute Removal [nonvolatile_toc] : 0.20000 : dimensionless : True : (0, None)
Solute Removal [toc] : 0.20000 : dimensionless : True : (0, None)
Solute Removal [tss] : 0.97000 : dimensionless : True : (0, None)
Water Recovery : 0.99000 : dimensionless : True : (0.0, 1.0000001)
------------------------------------------------------------------------------------
Stream Table
Units Inlet Treated Byproduct
Volumetric Flowrate meter ** 3 / second 0.013000 0.011530 0.0014700
Mass Concentration H2O kilogram / meter ** 3 769.23 858.63 68.027
Mass Concentration nonvolatile_toc kilogram / meter ** 3 76.923 69.384 136.05
Mass Concentration toc kilogram / meter ** 3 76.923 69.384 136.05
Mass Concentration tss kilogram / meter ** 3 76.923 2.6019 659.86
====================================================================================
The zero-order models rely on default model parameter values specified in YAML files. Users should supply their own values, if possible, instead of relying on the default parameter values. To use a local YAML database file, define the folder path to the file using the dbpath parameter for the Database() class. The line below defines the current working directory as the path for the YAML file.
model.db = Database(dbpath=".")
When using a local YAML file, the file name must be the same as the model name without the ZO letters. It must also use snake case style; for example, a YAML file for the DualMediaFiltrationZO() model must be named dual_media_filtration.yaml. See below for the contents of this YAML file.
# Contents of YAML file named dual_media_filtration.yaml
# This defines parameter values for the DualMediaFiltrationZO() zero-order model
default:
energy_electric_flow_vol_inlet:
value: 0.050718512
units: kWh/m^3
capital_cost:
basis: flow_vol
cost_factor: None
reference_state:
value: 4732.0
units: m^3/hr
capital_a_parameter:
value: 12.17829669e6
units: USD_2014
capital_b_parameter:
value: 0.5862
units: dimensionless
recovery_frac_mass_H2O:
value: 0.99
units: dimensionless
reference:
default_removal_frac_mass_comp:
value: 0
units: dimensionless
removal_frac_mass_comp:
nonvolatile_toc:
value: 0.2
units: dimensionless
constituent_longform: Nonvolatile TOC
toc:
value: 0.2
units: dimensionless
constituent_longform: Total Organic Carbon (TOC)
tss:
value: 0.97
units: dimensionless
constituent_longform: Total Suspended Solids (TSS)