HDA Flowsheet Simulation and Optimization
HDA Flowsheet Simulation and Optimization
Author: Jaffer Ghouse
Maintainer: Tanner Polley
Updated: 2026-1-12
Learning outcomes
Construct a steady-state flowsheet using the IDAES unit model library
Connecting unit models in a flowsheet using Arcs
Using the SequentialDecomposition tool to initialize a flowsheet with recycle
Formulate and solve an optimization problem
The general workflow of setting up an IDAES flowsheet is the following:
1 Importing Modules
2 Building a Model
3 Scaling the Model
4 Specifying the Model
5 Initializing the Model
6 Solving the Model
7 Analyzing and Visualizing the Results
8 Optimizing the Model
We will complete each of these steps as well as demonstrate analyses on this model through some examples and exercises.
Problem Statement
Hydrodealkylation is a chemical reaction that often involves reacting
an aromatic hydrocarbon in the presence of hydrogen gas to form a
simpler aromatic hydrocarbon devoid of functional groups. In this
example, toluene will be reacted with hydrogen gas at high temperatures
to form benzene via the following reaction:
C6H5CH3 + H2 → C6H6 + CH4
This reaction is often accompanied by an equilibrium side reaction
which forms diphenyl, which we will neglect for this example.
This example is based on the 1967 AIChE Student Contest problem as
present by Douglas, J.M., Chemical Design of Chemical Processes, 1988,
McGraw-Hill.
The flowsheet that we will be using for this module is shown below with the stream conditions. We will be processing toluene and hydrogen to produce at least 370 TPY of benzene. As shown in the flowsheet, there are two flash tanks, F101 to separate out the non-condensibles and F102 to further separate the benzene-toluene mixture to improve the benzene purity. Note that typically a distillation column is required to obtain high purity benzene but that is beyond the scope of this workshop. The non-condensibles separated out in F101 will be partially recycled back to M101 and the rest will be either purged or combusted for power generation.We will assume ideal gas for this flowsheet. The properties required for this module are available in the same directory:
hda_ideal_VLE.py
hda_reaction.py
The state variables chosen for the property package are flows of component by phase, temperature and pressure. The components considered are: toluene, hydrogen, benzene and methane. Therefore, every stream has 8 flow variables, 1 temperature and 1 pressure variable.

1 Importing Modules
1.1 Importing required Pyomo and IDAES components
To construct a flowsheet, we will need several components from the Pyomo and IDAES package. Let us first import the following components from Pyomo:
Constraint (to write constraints)
Var (to declare variables)
ConcreteModel (to create the concrete model object)
Expression (to evaluate values as a function of variables defined in the model)
Objective (to define an objective function for optimization)
SolverFactory (to solve the problem)
TransformationFactory (to apply certain transformations)
Arc (to connect two unit models)
SequentialDecomposition (to initialize the flowsheet in a sequential mode)
For further details on these components, please refer to the Pyomo documentation: https://Pyomo.readthedocs.io/en/stable/
From IDAES, we will be needing the FlowsheetBlock and the following unit models:
Feed
Mixer
Heater
StoichiometricReactor
Flash
Separator (splitter)
PressureChanger
Product
Inline Exercise:
Now, import the remaining unit models highlighted in blue above and run the cell using `Shift+Enter` after typing in the code.
We will also be needing some utility tools to put together the flowsheet and calculate the degrees of freedom.
1.2 Importing required thermo and reaction package
The final set of imports are to import the thermo and reaction package for the HDA process. We have created a custom thermo package that assumes Ideal Gas with support for VLE.
The reaction package here is very simple as we will be using only a StochiometricReactor and the reaction package consists of the stochiometric coefficients for the reaction and the parameter for the heat of reaction.
Let us import the following modules and they are in the same directory as this jupyter notebook:
- hda_ideal_VLE as thermo_props
- hda_reaction as reaction_props
2 Constructing the Flowsheet
We have now imported all the components, unit models, and property modules we need to construct a flowsheet. Let us create a ConcreteModel and add the flowsheet block.
We now need to add the property packages to the flowsheet. Unlike Module 1, where we only had a thermo property package, for this flowsheet we will also need to add a reaction property package.
2.1 Adding Unit Models
Let us start adding the unit models we have imported to the flowsheet. Here, we are adding the Feed (assigned a name I101 for Inlet), Mixer (assigned a name M101) and a Heater (assigned a name H101). Note that, all unit models need to be given a property package argument. In addition to that, there are several arguments depending on the unit model, please refer to the documentation for more details (https://idaes-pse.readthedocs.io/en/stable/reference_guides/model_libraries/generic/unit_models/index.html). For example, the Mixer unit model here must be specified the number of inlets that it will take in and the Heater can have specific settings enabled such as has_pressure_change or has_phase_equilibrium.
Let us now add the Flash(assign the name F101) and pass the following arguments:
- ”property_package”: m.fs.thermo_params
- ”has_heat_transfer”: True
- ”has_pressure_change”: False
Let us now add the Splitter(S101) with specific names for its output (purge and recycle), PressureChanger(C101) and the second Flash(F102).
Last, we will add the three Product blocks (P101, P102, P103). We use Feed blocks and Product blocks for convenience with reporting stream summaries and consistency
2.2 Connecting Unit Models using Arcs
We have now added all the unit models we need to the flowsheet. However, we have not yet specified how the units are to be connected. To do this, we will be using the Arc which is a Pyomo component that takes in two arguments: source and destination. Let us connect the outlet of the inlets (I101, I102) to the inlet of the mixer (M101) and outlet of the mixer to the inlet of the heater(H101).

We will now be connecting the rest of the flowsheet as shown below. Notice how the outlet names are different for the flash tanks F101 and F102 as they have a vapor and a liquid outlet.
Last we will connect the outlet streams to the inlets of the Product blocks (P101, P102, P103)
We have now connected the unit model block using the arcs. However, each of these arcs link to ports on the two unit models that are connected. In this case, the ports consist of the state variables that need to be linked between the unit models. Pyomo provides a convenient method to write these equality constraints for us between two ports and this is done as follows:
2.3 Adding expressions to compute purity and operating costs
In this section, we will add a few Expressions that allows us to evaluate the performance. Expressions provide a convenient way of calculating certain values that are a function of the variables defined in the model. For more details on Expressions, please refer to: https://pyomo.readthedocs.io/en/stable/explanation/modeling/network.html.
For this flowsheet, we are interested in computing the purity of the product Benzene stream (i.e. the mole fraction) and the operating cost which is a sum of the cooling and heating cost.
Let us first add an Expression to compute the mole fraction of benzene in the vap_outlet of F102 which is our product stream. Please note that the var flow_mol_phase_comp has the index - [time, phase, component]. As this is a steady-state flowsheet, the time index by default is 0. The valid phases are [“Liq”, “Vap”]. Similarly the valid component list is [“benzene”, “toluene”, “hydrogen”, “methane”].
Now, let us add an expression to compute the cooling cost assuming a cost of 0.212E-4 $/kW. Note that cooling utility is required for the reactor (R101) and the first flash (F101).
Now, let us add an expression to compute the heating cost assuming the utility cost as follows:
- 2.2E-4 dollars/kW for H101
- 1.9E-4 dollars/kW for F102
Note that the heat duty is in units of watt (J/s).
Let us now add an expression to compute the total operating cost per year which is basically the sum of the cooling and heating cost we defined above.
4 Specifying the Model
4.1 Fixing feed conditions
Let us first check how many degrees of freedom exist for this flowsheet using the degrees_of_freedom tool we imported earlier.
We will now be fixing the toluene feed (I101) stream to the conditions shown in the flowsheet above. Please note
that though this is a pure toluene feed, the remaining components are still assigned a very small non-zero value to
help with convergence and initializing. We will be importing a function that will specify the inlet conditions for
this example.
4.2 Fixing unit model specifications
Now that we have fixed our inlet feed conditions, we will now be fixing the operating conditions for the unit models in the flowsheet. Let us set set the H101 outlet temperature to 600 K.
For the StoichiometricReactor, we have to define the conversion in terms of toluene. This requires us to create a new variable for specifying the conversion and adding a Constraint that defines the conversion with respect to toluene. The second degree of freedom for the reactor is to define the heat duty. In this case, let us assume the reactor to be adiabatic i.e. Q = 0.
The Flash conditions for F101 can be set as follows.
Let us fix the purge split fraction to 20% and the outlet pressure of the compressor is set to 350000 Pa.
5 Initializing the Model
When a flowsheet contains a recycle loop, the outlet of a downstream unit becomes the inlet of an upstream unit, creating a cyclic dependency that prevents straightforward calculation of all stream conditions. The tear‐stream method is necessary because it “breaks” this loop: you select one recycle stream as the tear, assign it an initial guess, and then solve the rest of the flowsheet as if it were acyclic. Once the downstream units compute their outputs, you compare the calculated value of the torn stream to your initial guess and iteratively adjust until they coincide. Without tearing, the solver cannot establish a proper topological sequence or drive the recycle to convergence, making initialization—and ultimately steady‐state convergence—impossible.
It is important to determine the tear stream for a flowsheet which will be demonstrated below.

Currently, there are two methods of initializing a full flowsheet: using the sequential decomposition tool, or
manually propagating through the flowsheet. The tear stream in this example will be the stream from the mixer to the heater since that is where the
recycle stream first enters back into the main process.
First, we will highlight some helpful functions that are used in the initialization process.
This first function will take any unit model and can either initialize the model with its respective default
initializer, or use a generic solver and the solve the current state of the unit model. Often times a direct
initialization method will fail while a solving method will converge so having the option for both is helpful.
5.1 Sequential Decomposition
This section will demonstrate how to use the built-in sequential decomposition tool to initialize our flowsheet. Sequential Decomposition is a tool from Pyomo where the documentation can be found here https://Pyomo.readthedocs.io/en/stable/explanation/modeling/network.html#sequential-decomposition
We are now ready to initialize our flowsheet in a sequential mode. Note that we specifically set the iteration limit
to be 5 as we are trying to use this tool only to get a good set of initial values such that IPOPT can then take over
and solve this flowsheet for us. Uncomment this function call to run the automatic propagation method
5.2 Manual Propagation Method
This method uses a more direct approach to initialize the flowsheet, using the updated initializer method and propagating manually through the flowsheet and solving for the tear stream directly.
Lets define the function that will help us manually propagate and step through the flowsheet
It will first show that the degrees of freedom is correctly at 0 before any streams are deactivated. Once the tear
stream is deactivated though, the degrees of freedom will be 10. That means 10 variables will have to be defined with
the tear guesses tear_guesses. Then each unit model can be initialized with our same helper function and then can
propagate the corresponding connection to the following unit models. At the end, the whole flowsheet is solved,
giving a much better chance for the recycle stream to be used correctly the flowsheet to converge.
The DOF is 0 initially
The DOF is 10 after deactivating the tear stream
The DOF is 0 after setting the tear stream
The DOF is 0 after unfixing the values and reactivating the tear stream
6 Solving the Model
We have now initialized the flowsheet. Lets set up some solving options before simulating the flowsheet. We want to specify the scaling method, number of iterations, and tolerance. More specific or advanced options can be found at the documentation for IPOPT https://coin-or.github.io/Ipopt/OPTIONS.html
Ipopt 3.13.2: linear_solver="ma57"
max_iter=1000
nlp_scaling_method="user-scaling"
tol=1e-08
option_file_name="C:\Users\Tanner\AppData\Local\Temp\tmpjzf4e172\unknown.31496.43076.opt"
Using option file "C:\Users\Tanner\AppData\Local\Temp\tmpjzf4e172\unknown.31496.43076.opt".
******************************************************************************
This program contains Ipopt, a library for large-scale nonlinear optimization.
Ipopt is released as open source code under the Eclipse Public License (EPL).
For more information visit http://projects.coin-or.org/Ipopt
This version of Ipopt was compiled from source code available at
https://github.com/IDAES/Ipopt as part of the Institute for the Design of
Advanced Energy Systems Process Systems Engineering Framework (IDAES PSE
Framework) Copyright (c) 2018-2019. See https://github.com/IDAES/idaes-pse.
This version of Ipopt was compiled using HSL, a collection of Fortran codes
for large-scale scientific computation. All technical papers, sales and
publicity material resulting from use of the HSL codes within IPOPT must
contain the following acknowledgement:
HSL, a collection of Fortran codes for large-scale scientific
computation. See http://www.hsl.rl.ac.uk.
******************************************************************************
This is Ipopt version 3.13.2, running with linear solver ma57.
Number of nonzeros in equality constraint Jacobian...: 920
Number of nonzeros in inequality constraint Jacobian.: 0
Number of nonzeros in Lagrangian Hessian.............: 456
Total number of variables............................: 218
variables with only lower bounds: 56
variables with lower and upper bounds: 155
variables with only upper bounds: 0
Total number of equality constraints.................: 218
Total number of inequality constraints...............: 0
inequality constraints with only lower bounds: 0
inequality constraints with lower and upper bounds: 0
inequality constraints with only upper bounds: 0
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
0 0.0000000e+00 8.17e+03 1.00e+00 -1.0 0.00e+00 - 0.00e+00 0.00e+00 0
Reallocating memory for MA57: lfact (10193)
1 0.0000000e+00 7.12e+03 2.01e+02 -1.0 4.35e+04 - 4.68e-02 1.56e-01h 1
2 0.0000000e+00 7.12e+03 2.74e+02 -1.0 4.20e+05 - 9.82e-04 5.24e-04h 1
3 0.0000000e+00 7.11e+03 2.06e+03 -1.0 4.26e+05 - 1.43e-05 1.49e-03f 1
4 0.0000000e+00 7.09e+03 1.83e+03 -1.0 3.65e+04 - 5.78e-03 2.02e-03h 1
5 0.0000000e+00 7.09e+03 1.82e+03 -1.0 1.61e+05 - 4.69e-04 1.23e-05h 1
6r 0.0000000e+00 7.09e+03 9.99e+02 3.9 0.00e+00 - 0.00e+00 6.02e-08R 2
7r 0.0000000e+00 6.68e+03 9.98e+02 3.9 7.11e+06 - 5.22e-04 1.63e-04f 1
8r 0.0000000e+00 4.74e+04 9.98e+02 3.9 3.89e+06 - 2.84e-04 7.21e-04f 1
9r 0.0000000e+00 4.77e+04 1.78e+04 3.9 1.73e+06 - 4.34e-02 5.81e-04f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
10r 0.0000000e+00 4.55e+04 4.83e+04 3.2 4.71e+04 - 2.92e-01 4.47e-02f 1
11r 0.0000000e+00 7.86e+04 3.48e+04 3.2 3.13e+02 - 4.51e-01 3.27e-01f 1
12r 0.0000000e+00 4.85e+04 2.80e+04 3.2 5.27e+01 - 5.22e-01 2.61e-01f 1
13r 0.0000000e+00 1.68e+05 1.76e+04 3.2 1.46e+02 - 8.30e-01 4.81e-01f 1
14r 0.0000000e+00 8.02e+04 3.21e+03 3.2 1.42e+02 - 7.28e-01 1.00e+00f 1
15r 0.0000000e+00 1.89e+05 6.22e+04 3.2 1.06e+02 - 4.83e-01 1.00e+00f 1
16r 0.0000000e+00 1.77e+05 5.95e+04 3.2 1.08e+02 0.0 9.89e-02 6.28e-02h 1
17r 0.0000000e+00 1.03e+05 3.98e+04 3.2 8.09e+01 - 7.18e-01 4.22e-01h 1
18r 0.0000000e+00 8.88e+04 8.50e+04 3.2 1.59e+02 - 2.14e-01 1.36e-01h 1
19r 0.0000000e+00 5.30e+04 1.71e+06 3.2 8.69e+01 - 3.02e-02 3.51e-01f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
20r 0.0000000e+00 1.40e+04 2.20e+05 3.2 1.08e+01 2.2 6.72e-01 8.78e-01f 1
21r 0.0000000e+00 9.61e+03 9.51e+04 2.5 1.06e+01 1.8 9.32e-01 4.27e-01f 1
22r 0.0000000e+00 1.83e+04 3.37e+04 2.5 1.51e+01 1.3 1.00e+00 6.41e-01f 1
23r 0.0000000e+00 3.76e+03 1.35e+03 2.5 4.90e+00 0.8 1.00e+00 1.00e+00f 1
24r 0.0000000e+00 1.38e+05 2.72e+04 2.5 1.06e+02 - 3.87e-01 1.00e+00f 1
25r 0.0000000e+00 1.06e+05 2.11e+04 2.5 5.11e+01 1.2 2.99e-01 2.35e-01h 1
26r 0.0000000e+00 9.35e+04 1.83e+04 2.5 3.27e+01 2.6 6.94e-02 1.19e-01h 1
27r 0.0000000e+00 9.23e+03 3.61e+03 2.5 2.06e+01 2.1 2.35e-01 1.00e+00h 1
28r 0.0000000e+00 9.21e+03 6.60e+03 2.5 9.05e+02 - 1.37e-01 3.89e-03f 1
29r 0.0000000e+00 6.69e+04 1.34e+04 2.5 1.58e+02 - 3.39e-01 2.01e-01f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
30r 0.0000000e+00 7.42e+01 3.52e+04 2.5 3.26e-01 1.6 4.89e-01 1.00e+00f 1
31r 0.0000000e+00 9.36e+03 1.66e+02 2.5 1.29e+01 - 1.00e+00 1.00e+00f 1
32r 0.0000000e+00 9.30e+01 3.75e+00 2.5 1.85e+00 - 1.00e+00 1.00e+00h 1
33r 0.0000000e+00 8.97e+03 9.16e+02 0.4 4.59e+01 - 7.14e-01 7.41e-01f 1
34r 0.0000000e+00 7.19e+03 3.37e+02 0.4 2.34e+03 - 7.23e-01 6.68e-01f 1
35r 0.0000000e+00 5.64e+03 5.42e+02 0.4 7.33e+02 - 6.81e-01 5.42e-01f 1
36r 0.0000000e+00 1.10e+03 1.79e+02 0.4 2.38e-01 2.0 6.12e-01 8.67e-01f 1
37r 0.0000000e+00 3.67e+02 1.23e+02 0.4 9.76e-02 2.5 9.90e-01 8.27e-01f 1
38r 0.0000000e+00 2.93e+01 3.80e+02 0.4 2.55e-01 2.0 5.41e-01 1.00e+00f 1
39r 0.0000000e+00 2.58e+01 7.52e+02 0.4 2.70e+00 2.4 4.08e-02 9.27e-02h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
40r 0.0000000e+00 1.03e+01 2.85e+02 0.4 8.74e-02 2.8 7.74e-01 6.78e-01f 1
41r 0.0000000e+00 4.85e+00 8.16e+01 0.4 2.96e-01 2.4 7.04e-01 7.21e-01f 1
42r 0.0000000e+00 1.15e+02 7.32e+01 -0.3 1.76e-01 1.9 7.14e-01 7.59e-01f 1
43r 0.0000000e+00 2.10e+02 3.61e+02 -0.3 4.28e-01 1.4 7.77e-01 1.77e-01f 1
44r 0.0000000e+00 1.51e+02 6.63e+01 -0.3 4.68e-01 0.9 1.00e+00 8.94e-01f 1
45r 0.0000000e+00 9.19e+00 1.85e+01 -0.3 1.49e-01 1.3 1.00e+00 1.00e+00f 1
46r 0.0000000e+00 5.62e+00 5.71e+01 -0.3 1.05e+00 0.9 4.17e-01 3.89e-01h 1
47r 0.0000000e+00 1.98e+01 3.77e+01 -0.3 7.16e-01 0.4 1.00e+00 1.00e+00f 1
48r 0.0000000e+00 1.82e+01 6.27e+02 -0.3 9.97e+00 -0.1 4.98e-02 8.93e-02h 1
49r 0.0000000e+00 1.72e+01 5.84e+02 -0.3 1.90e+00 1.2 4.67e-02 4.96e-02f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
50r 0.0000000e+00 1.16e+01 7.04e+02 -0.3 1.10e+00 0.8 6.53e-01 4.12e-01f 1
51r 0.0000000e+00 1.08e+01 6.28e+02 -0.3 2.94e-01 2.1 3.66e-01 6.78e-02f 1
52r 0.0000000e+00 6.69e+00 7.88e+02 -0.3 4.74e-01 1.6 5.14e-01 6.14e-01f 1
53r 0.0000000e+00 6.34e+00 1.39e+03 -0.3 6.49e-02 2.9 1.00e+00 5.17e-02h 1
54r 0.0000000e+00 5.30e-01 7.34e+02 -0.3 1.91e-01 2.5 5.47e-01 1.00e+00f 1
55r 0.0000000e+00 5.30e-01 8.37e+02 -0.3 1.09e-01 2.9 1.00e+00 1.86e-01f 1
56r 0.0000000e+00 6.24e-01 3.25e+02 -0.3 2.18e-01 2.4 7.22e-01 7.62e-01f 1
57r 0.0000000e+00 5.84e-01 1.25e+03 -0.3 1.10e-01 2.8 3.44e-01 6.58e-02f 1
58r 0.0000000e+00 1.84e+00 9.86e+02 -0.3 6.56e-01 2.4 4.76e-01 1.66e-01f 1
59r 0.0000000e+00 9.98e+00 7.31e+02 -0.3 2.98e-01 1.9 3.81e-01 1.96e-01f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
60r 0.0000000e+00 2.33e+01 6.73e+02 -0.3 2.93e+00 1.4 1.64e-03 2.62e-02f 1
61r 0.0000000e+00 2.09e+02 6.21e+02 -0.3 3.68e+00 1.8 2.80e-02 4.31e-02f 1
62r 0.0000000e+00 2.06e+02 4.81e+02 -0.3 4.45e-01 1.4 4.03e-01 1.68e-02h 1
63r 0.0000000e+00 1.65e+02 3.87e+02 -0.3 1.11e+00 0.9 1.92e-02 1.96e-01f 1
64r 0.0000000e+00 1.50e+02 3.08e+02 -0.3 1.85e+00 0.4 2.04e-01 2.07e-01f 1
65r 0.0000000e+00 1.42e+02 2.98e+02 -0.3 1.20e+00 1.7 3.04e-02 5.07e-02f 1
66r 0.0000000e+00 7.46e+01 5.29e+02 -0.3 5.27e-02 2.2 9.16e-01 4.78e-01f 1
67r 0.0000000e+00 5.57e+01 4.82e+02 -0.3 1.72e-01 1.7 9.61e-01 2.54e-01f 1
68r 0.0000000e+00 2.98e+00 1.46e+02 -0.3 2.22e-01 1.2 1.00e+00 9.79e-01f 1
69r 0.0000000e+00 6.01e+00 2.34e+02 -0.3 4.07e-01 0.7 5.24e-01 4.28e-01f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
70r 0.0000000e+00 1.07e+02 5.44e+02 -0.3 1.11e+00 0.3 7.04e-01 1.00e+00f 1
71r 0.0000000e+00 2.25e+01 7.39e+02 -0.3 1.39e-01 1.6 3.98e-01 7.90e-01f 1
72r 0.0000000e+00 2.07e+01 7.10e+02 -0.3 6.94e-01 1.1 2.42e-01 8.16e-02f 1
73r 0.0000000e+00 4.67e+01 3.79e+02 -0.3 3.86e-01 0.6 6.91e-01 1.00e+00f 1
74r 0.0000000e+00 7.77e+01 2.65e+02 -0.3 9.27e-01 0.2 4.94e-01 4.38e-01h 1
75r 0.0000000e+00 7.62e+01 2.61e+02 -0.3 3.81e+00 0.6 2.20e-02 3.06e-02f 2
76r 0.0000000e+00 5.81e+01 2.16e+02 -0.3 1.57e-01 1.9 3.64e-01 2.38e-01f 1
77r 0.0000000e+00 1.97e+01 1.33e+02 -0.3 1.61e-01 1.4 1.00e+00 6.92e-01f 1
78r 0.0000000e+00 4.47e+01 2.11e+02 -0.3 8.61e-01 1.0 7.64e-01 4.57e-01f 1
79r 0.0000000e+00 2.75e+02 1.68e+02 -0.3 2.89e+00 0.5 1.90e-01 1.97e-01f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
80r 0.0000000e+00 1.57e+01 5.93e+01 -0.3 1.06e-01 1.8 1.00e+00 1.00e+00f 1
81r 0.0000000e+00 4.52e+00 7.54e+00 -0.3 3.54e-01 1.3 1.00e+00 1.00e+00h 1
82r 0.0000000e+00 1.51e+01 6.83e+01 -1.0 1.48e-01 1.8 6.09e-01 6.86e-01f 1
83r 0.0000000e+00 9.47e+00 2.62e+01 -1.0 5.68e-02 2.2 1.00e+00 8.94e-01f 1
84r 0.0000000e+00 2.30e+01 2.17e+01 -1.0 4.35e-01 1.7 1.62e-01 1.76e-01f 1
85r 0.0000000e+00 1.67e+01 1.83e+02 -1.0 8.29e-02 2.1 1.00e+00 4.80e-01f 1
86r 0.0000000e+00 5.83e+01 5.12e+02 -1.0 3.20e-01 1.7 6.90e-01 3.58e-01f 1
87r 0.0000000e+00 1.07e+02 1.19e+03 -1.0 1.30e+01 1.2 2.99e-02 1.02e-02f 1
88r 0.0000000e+00 1.05e+02 3.60e+02 -1.0 2.66e+00 0.7 1.00e+00 2.59e-02f 1
89r 0.0000000e+00 4.13e+02 4.81e+02 -1.0 7.27e+00 0.2 1.00e+00 4.22e-01f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
90r 0.0000000e+00 4.12e+02 4.73e+02 -1.0 7.91e+01 -0.3 2.91e-03 3.88e-03f 1
91r 0.0000000e+00 3.90e+02 5.09e+02 -1.0 1.05e+00 1.1 1.00e+00 5.42e-02f 1
92r 0.0000000e+00 6.42e+02 1.96e+01 -1.0 3.03e+00 0.6 1.00e+00 1.00e+00f 1
93r 0.0000000e+00 1.54e+03 5.81e+02 -1.0 1.25e+01 0.1 9.40e-02 6.11e-01f 1
94r 0.0000000e+00 1.52e+03 5.61e+02 -1.0 9.43e+00 0.5 1.64e-02 8.32e-03f 1
95r 0.0000000e+00 1.38e+03 3.41e+02 -1.0 2.32e+01 0.1 3.92e-01 1.27e-01f 1
96r 0.0000000e+00 1.38e+03 3.72e+02 -1.0 5.95e+00 0.5 3.61e-01 4.34e-03h 1
97r 0.0000000e+00 1.28e+03 2.01e+02 -1.0 1.09e+01 0.0 4.23e-02 1.05e-01f 1
98r 0.0000000e+00 9.89e+02 4.20e+02 -1.0 4.94e+00 0.4 3.76e-02 2.66e-01f 1
99r 0.0000000e+00 8.96e+02 4.65e+02 -1.0 2.96e+00 0.9 2.83e-01 9.51e-02f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
100r 0.0000000e+00 8.38e+02 1.08e+03 -1.0 3.79e+00 0.4 5.07e-01 6.96e-02h 1
101r 0.0000000e+00 1.19e+03 6.44e+02 -1.0 9.81e+00 -0.1 3.71e-01 3.57e-01f 1
102r 0.0000000e+00 1.19e+03 5.28e+02 -1.0 1.78e+01 -0.6 7.44e-03 6.07e-02f 1
103r 0.0000000e+00 1.02e+03 3.34e+02 -1.0 2.10e+01 -1.0 4.17e-02 1.21e-01f 1
104r 0.0000000e+00 9.98e+02 8.36e+02 -1.0 8.35e+00 -0.6 4.71e-01 1.95e-02h 1
105r 0.0000000e+00 6.83e+02 6.45e+02 -1.0 1.30e+01 -1.1 5.71e-02 2.84e-01f 1
106r 0.0000000e+00 8.65e+02 1.14e+03 -1.0 8.25e+00 -0.7 1.61e-01 6.21e-01f 1
107r 0.0000000e+00 7.16e+02 9.70e+02 -1.0 4.28e+00 -0.2 1.93e-01 1.57e-01h 1
108r 0.0000000e+00 6.31e+02 8.28e+02 -1.0 6.49e+00 -0.7 6.61e-02 1.81e-01h 1
109r 0.0000000e+00 4.55e+02 1.19e+03 -1.0 2.95e+00 -0.3 1.88e-01 8.74e-01h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
110r 0.0000000e+00 1.83e+02 4.89e+02 -1.0 1.15e-01 1.9 6.47e-01 5.98e-01h 1
111r 0.0000000e+00 3.73e+01 1.31e+02 -1.0 8.98e-02 1.5 1.00e+00 7.95e-01h 1
112r 0.0000000e+00 7.86e+00 8.49e+01 -1.0 7.76e-02 1.9 9.93e-01 7.86e-01h 1
113r 0.0000000e+00 2.86e+00 1.42e+01 -1.0 1.00e-01 1.4 1.00e+00 1.00e+00h 1
114r 0.0000000e+00 2.89e+00 2.59e+00 -1.0 3.00e-01 0.9 1.00e+00 1.00e+00f 1
115r 0.0000000e+00 5.21e+01 6.10e+00 -1.0 8.19e-01 0.5 1.00e+00 1.00e+00f 1
116r 0.0000000e+00 1.36e+02 4.46e+02 -1.0 2.16e+00 -0.0 2.00e-01 5.43e-01f 1
117r 0.0000000e+00 2.35e+01 1.35e+02 -1.0 3.81e-02 2.2 6.64e-01 8.26e-01h 1
118r 0.0000000e+00 1.45e+01 6.04e+02 -1.0 4.14e-01 1.7 1.30e-01 6.39e-01f 1
119r 0.0000000e+00 7.09e+01 1.51e+03 -1.0 1.49e+00 2.2 9.44e-02 3.42e-01f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
120r 0.0000000e+00 6.91e+01 1.74e+03 -1.0 3.65e-01 2.6 2.02e-01 2.71e-02f 1
121r 0.0000000e+00 6.89e+01 1.47e+03 -1.0 1.29e+00 2.1 8.23e-04 3.05e-03f 1
122r 0.0000000e+00 6.81e+01 2.26e+03 -1.0 1.01e+00 1.6 5.80e-02 1.11e-02f 1
123r 0.0000000e+00 5.53e+01 8.13e+02 -1.0 9.48e-01 1.2 1.55e-02 1.67e-01f 1
124r 0.0000000e+00 4.39e+01 6.51e+02 -1.0 6.05e-01 0.7 2.20e-01 1.95e-01f 1
125r 0.0000000e+00 3.95e+01 5.85e+02 -1.0 1.15e+00 0.2 4.00e-01 9.82e-02f 1
126r 0.0000000e+00 5.31e+01 2.97e+02 -1.0 1.75e+00 -0.3 4.11e-03 3.31e-01f 1
127r 0.0000000e+00 5.22e+01 2.92e+02 -1.0 1.49e+00 0.2 4.34e-02 1.79e-02h 1
128r 0.0000000e+00 5.15e+01 2.70e+02 -1.0 9.28e+00 -0.3 1.26e-01 3.54e-02f 1
129r 0.0000000e+00 2.87e+01 8.41e+01 -1.0 1.20e+00 0.1 9.87e-01 7.24e-01h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
130r 0.0000000e+00 5.74e+01 7.12e+01 -1.0 2.02e+00 -0.4 1.00e+00 3.08e-01h 1
131r 0.0000000e+00 1.40e+03 2.57e+01 -1.0 6.81e+00 -0.9 6.75e-01 8.23e-01f 1
132r 0.0000000e+00 1.35e+03 2.54e+01 -1.0 1.62e+01 -1.3 1.03e-01 3.34e-02h 1
133r 0.0000000e+00 1.23e+03 3.95e+01 -1.0 7.83e+00 -0.9 7.40e-01 6.60e-01h 1
134r 0.0000000e+00 1.19e+03 3.30e+02 -1.0 1.81e+01 -1.4 3.93e-01 5.73e-02h 1
135r 0.0000000e+00 1.18e+03 3.16e+02 -1.0 1.12e+02 -1.9 2.06e-02 2.35e-02h 1
136r 0.0000000e+00 3.04e+03 1.74e+02 -1.0 1.66e+01 -1.4 6.20e-01 5.67e-01h 1
137r 0.0000000e+00 3.10e+03 7.86e+01 -1.0 4.18e+02 -1.9 4.32e-04 5.13e-03f 1
138r 0.0000000e+00 3.15e+03 8.59e+01 -1.0 2.08e+01 -1.5 6.10e-01 3.20e-01f 1
139r 0.0000000e+00 6.79e+03 9.92e+01 -1.0 6.29e+01 -2.0 5.13e-01 5.43e-01h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
140r 0.0000000e+00 1.99e+03 2.93e+02 -1.0 1.82e-01 1.2 9.52e-01 7.07e-01h 1
141r 0.0000000e+00 4.14e-01 6.19e+01 -1.0 4.03e-02 1.6 9.05e-01 1.00e+00h 1
142r 0.0000000e+00 5.40e-01 1.00e+01 -1.0 7.66e-02 1.1 1.00e+00 1.00e+00h 1
143r 0.0000000e+00 1.87e+00 7.98e-01 -1.0 1.80e-01 0.6 1.00e+00 1.00e+00h 1
144r 0.0000000e+00 1.04e+01 9.40e-01 -1.0 4.36e-01 0.2 1.00e+00 1.00e+00h 1
145r 0.0000000e+00 3.19e+01 4.06e+00 -1.0 9.89e-01 -0.3 1.00e+00 1.00e+00h 1
146r 0.0000000e+00 2.28e+02 6.27e+00 -1.0 3.02e+00 -0.8 1.00e+00 9.35e-01h 1
147r 0.0000000e+00 7.58e+02 1.93e+02 -1.0 1.17e+01 -1.3 1.00e+00 5.43e-01h 1
148r 0.0000000e+00 7.62e+02 6.49e+02 -1.0 5.17e+01 -1.7 4.76e-01 9.10e-02h 1
149r 0.0000000e+00 5.18e+03 4.98e+02 -1.0 3.35e+02 -2.2 2.78e-02 1.43e-01f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
150r 0.0000000e+00 5.19e+03 7.41e+02 -1.0 1.23e+03 -2.7 1.42e-02 2.95e-02f 1
151r 0.0000000e+00 6.87e+03 9.57e+02 -1.0 1.12e+03 -2.3 1.35e-03 3.17e-02f 1
152r 0.0000000e+00 6.85e+03 8.50e+02 -1.0 1.37e+02 -1.8 3.99e-01 4.06e-03h 1
153r 0.0000000e+00 6.72e+03 9.57e+02 -1.0 4.39e+02 -2.3 1.18e-01 1.81e-02h 1
154r 0.0000000e+00 6.40e+03 1.13e+03 -1.0 1.07e+04 - 1.49e-01 4.89e-02f 1
155r 0.0000000e+00 5.62e+03 9.92e+02 -1.0 9.94e+03 - 1.20e-01 1.22e-01f 1
156r 0.0000000e+00 5.58e+03 9.64e+02 -1.0 3.35e+03 - 1.73e-03 7.88e-03h 1
157r 0.0000000e+00 5.58e+03 9.64e+02 -1.0 2.55e+05 -2.8 2.32e-05 2.33e-05f 1
158r 0.0000000e+00 5.55e+03 1.02e+03 -1.0 4.99e+02 -3.3 2.90e-02 5.00e-03h 1
159r 0.0000000e+00 4.91e+03 9.36e+02 -1.0 1.06e+02 -3.8 1.63e-01 1.16e-01h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
160r 0.0000000e+00 4.19e+03 7.63e+02 -1.0 1.75e+02 -2.4 1.15e-02 1.48e-01h 1
161r 0.0000000e+00 4.18e+03 7.94e+02 -1.0 4.34e+02 -2.9 3.97e-02 1.46e-03h 1
162r 0.0000000e+00 2.31e+03 3.53e+02 -1.0 5.33e+03 - 1.01e-01 4.63e-01h 1
163r 0.0000000e+00 2.04e+03 5.97e+02 -1.0 3.18e+03 - 1.73e-01 1.20e-01h 1
164r 0.0000000e+00 1.26e+03 3.46e+02 -1.0 3.03e+03 - 4.18e-01 4.11e-01h 1
165r 0.0000000e+00 1.24e+03 3.20e+02 -1.0 2.32e+03 - 1.97e-03 1.44e-02h 1
166r 0.0000000e+00 1.17e+03 4.22e+02 -1.0 2.31e+03 - 3.37e-01 5.42e-02h 1
167r 0.0000000e+00 1.04e+03 6.87e+02 -1.0 1.74e+03 - 9.08e-01 1.16e-01h 1
168r 0.0000000e+00 3.09e+02 4.10e+02 -1.0 1.64e+03 - 4.91e-01 8.06e-01h 1
169r 0.0000000e+00 3.95e+02 5.59e+02 -1.0 2.46e+03 - 1.49e-02 2.83e-02f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
170r 0.0000000e+00 2.99e+02 7.69e+01 -1.0 4.31e+02 - 8.88e-01 1.00e+00f 1
171r 0.0000000e+00 1.65e+02 3.84e+02 -1.0 4.91e-01 0.2 1.00e+00 4.50e-01h 1
172r 0.0000000e+00 1.87e-01 5.61e+01 -1.0 2.62e+00 - 1.00e+00 1.00e+00h 1
173r 0.0000000e+00 1.87e-01 2.09e+01 -1.0 8.62e-01 - 1.00e+00 1.00e+00h 1
174r 0.0000000e+00 1.87e-01 1.77e+00 -1.0 9.94e-02 - 1.00e+00 1.00e+00h 1
175r 0.0000000e+00 7.96e+00 5.39e+00 -1.7 1.21e+01 - 1.00e+00 9.98e-01f 1
176r 0.0000000e+00 2.31e+02 1.33e+02 -1.7 1.26e+04 - 3.42e-01 1.24e-01f 1
177r 0.0000000e+00 2.38e+02 3.38e+02 -1.7 1.05e+04 - 6.40e-01 3.94e-02f 1
178r 0.0000000e+00 2.37e+02 3.35e+02 -1.7 7.28e+03 - 9.97e-02 1.97e-03h 1
179r 0.0000000e+00 2.11e+02 3.90e+02 -1.7 3.85e+03 - 5.39e-01 1.07e-01h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
180r 0.0000000e+00 3.16e+02 4.17e+02 -1.7 3.82e+03 - 1.28e-02 9.51e-01f 1
181r 0.0000000e+00 1.07e+03 2.19e+02 -1.7 3.96e+03 - 4.42e-01 4.76e-01h 1
182r 0.0000000e+00 1.05e+03 2.05e+02 -1.7 1.41e+03 - 4.64e-01 2.04e-02h 1
183r 0.0000000e+00 4.56e+02 1.83e+02 -1.7 1.51e+00 -0.2 4.60e-01 5.66e-01h 1
184r 0.0000000e+00 4.46e+02 4.37e+02 -1.7 1.26e+03 - 5.85e-01 2.25e-02h 1
185r 0.0000000e+00 3.62e+02 5.95e+02 -1.7 1.17e+03 - 3.15e-01 2.25e-01h 1
186r 0.0000000e+00 3.47e+02 2.11e+02 -1.7 6.54e-01 -0.7 4.90e-01 4.12e-02h 1
187r 0.0000000e+00 2.68e+02 4.10e+02 -1.7 9.73e+02 - 1.74e-01 2.84e-01h 1
188r 0.0000000e+00 2.32e+02 7.23e+02 -1.7 1.37e+03 - 7.54e-01 3.83e-01h 1
189r 0.0000000e+00 2.25e+02 1.95e+02 -1.7 7.05e+02 - 6.62e-01 3.01e-02h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
190r 0.0000000e+00 1.61e+02 3.01e+02 -1.7 4.09e+02 - 1.00e+00 3.03e-01h 1
191r 0.0000000e+00 9.61e-01 6.13e-01 -1.7 6.25e+01 - 1.00e+00 1.00e+00h 1
192r 0.0000000e+00 5.56e-02 3.83e-02 -1.7 6.74e+00 - 1.00e+00 1.00e+00h 1
193r 0.0000000e+00 3.80e-01 2.41e+01 -3.9 2.90e+01 - 9.11e-01 7.83e-01f 1
194r 0.0000000e+00 2.60e+00 2.67e+01 -3.9 4.29e+04 - 7.72e-02 5.58e-02f 1
195r 0.0000000e+00 2.60e+00 3.11e+02 -3.9 2.37e+04 - 6.85e-02 1.39e-05h 1
196r 0.0000000e+00 2.91e+00 2.90e+02 -3.9 3.11e+03 - 1.53e-01 3.55e-02f 1
197r 0.0000000e+00 1.00e+01 2.50e+02 -3.9 2.55e+03 - 1.71e-01 1.67e-01f 1
198r 0.0000000e+00 2.87e+01 3.43e+02 -3.9 2.12e+03 - 7.25e-02 3.31e-01f 1
199r 0.0000000e+00 4.82e+01 9.78e+02 -3.9 1.55e+03 - 5.38e-02 5.45e-01f 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
200r 0.0000000e+00 1.40e+02 6.78e+02 -3.9 3.21e+04 - 2.94e-02 1.88e-01f 1
201r 0.0000000e+00 1.38e+02 6.81e+02 -3.9 2.53e+04 - 4.87e-02 1.94e-02h 1
202r 0.0000000e+00 1.43e+02 6.07e+02 -3.9 2.53e+04 - 2.36e-02 7.13e-02f 1
203r 0.0000000e+00 2.17e+02 4.73e+02 -3.9 2.36e+04 - 9.43e-02 1.98e-01f 1
204r 0.0000000e+00 2.11e+02 5.82e+02 -3.9 1.89e+04 - 5.56e-01 6.52e-02h 1
205r 0.0000000e+00 2.11e+02 7.24e+02 -3.9 1.33e+04 - 8.62e-01 3.50e-03h 1
206r 0.0000000e+00 1.88e+02 8.64e+02 -3.9 3.55e+02 - 1.00e+00 1.09e-01h 1
207r 0.0000000e+00 3.04e+01 5.52e+02 -3.9 3.16e+02 - 2.11e-01 8.62e-01h 1
208r 0.0000000e+00 7.41e-01 1.91e+00 -3.9 4.38e+01 - 1.00e+00 9.97e-01h 1
209r 0.0000000e+00 7.13e-01 6.42e+02 -3.9 1.50e-01 - 7.36e-02 3.78e-02h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
210r 0.0000000e+00 5.37e-03 4.03e+02 -3.9 1.44e-01 - 5.86e-01 1.00e+00h 1
211r 0.0000000e+00 5.37e-03 2.68e-04 -3.9 2.52e-03 - 1.00e+00 1.00e+00h 1
212r 0.0000000e+00 5.37e-03 5.94e+01 -5.9 3.33e-01 - 1.00e+00 6.67e-01f 1
213r 0.0000000e+00 4.67e+01 1.51e+02 -5.9 2.60e+04 - 1.03e-01 2.28e-02f 1
214r 0.0000000e+00 4.67e+01 8.78e+02 -5.9 4.07e+02 - 8.75e-01 9.73e-07h 2
215r 0.0000000e+00 1.68e+01 2.98e+02 -5.9 1.59e-01 - 8.59e-01 6.40e-01h 1
216r 0.0000000e+00 2.59e+00 5.90e+01 -5.9 3.25e-02 - 1.00e+00 8.46e-01h 1
217r 0.0000000e+00 1.57e-04 3.42e-04 -5.9 3.65e-03 - 1.00e+00 1.00e+00h 1
218r 0.0000000e+00 2.69e-09 6.22e-06 -5.9 2.22e-04 - 1.00e+00 1.00e+00h 1
Number of Iterations....: 218
(scaled) (unscaled)
Objective...............: 0.0000000000000000e+00 0.0000000000000000e+00
Dual infeasibility......: 0.0000000000000000e+00 0.0000000000000000e+00
Constraint violation....: 2.6943874215090702e-09 2.6943874215090702e-09
Complementarity.........: 0.0000000000000000e+00 0.0000000000000000e+00
Overall NLP error.......: 2.6943874215090702e-09 2.6943874215090702e-09
Number of objective function evaluations = 225
Number of objective gradient evaluations = 8
Number of equality constraint evaluations = 225
Number of inequality constraint evaluations = 0
Number of equality constraint Jacobian evaluations = 220
Number of inequality constraint Jacobian evaluations = 0
Number of Lagrangian Hessian evaluations = 218
Total CPU secs in IPOPT (w/o function evaluations) = 0.347
Total CPU secs in NLP function evaluations = 0.036
EXIT: Optimal Solution Found.
7 Analyze the results
If the IDAES UI package was installed with the idaes-pse installation or installed separately, you can run the flowsheet visualizer to see a full diagram of the full process that is generated and displayed on a browser window.
Otherwise, we can run the m.fs.report() method to see a full summary of the solved flowsheet. It is recommended to adjust the width of the output as much as possible for the cleanest display.
====================================================================================
Flowsheet : fs Time: 0.0
------------------------------------------------------------------------------------
Stream Table
Units s01 s02 s03 s04 s05 s06 s07 s08 s09 s10 s11 s12
Total Molar Flowrate Liq mole / second 0.30001 2.0000e-05 0.34190 1.6073e-09 5.7340e-09 1.0000e-08 0.26712 1.1139e-06 1.1143e-06 1.0000e-08 0.094878 2.7856e-07
Total Molar Flowrate Vap mole / second 4.0000e-05 0.32002 1.6901 2.0320 2.0320 1.7648 1.0000e-08 1.4119 1.4119 0.17224 1.0000e-08 0.35297
Total Mole Fraction ('Liq', 'benzene') dimensionless 3.3332e-05 0.50000 0.22733 0.13374 0.63390 0.76595 0.76595 0.76595 0.76595 0.66001 0.66001 0.76595
Total Mole Fraction ('Liq', 'toluene') dimensionless 0.99997 0.50000 0.77267 0.86626 0.36610 0.23405 0.23405 0.23405 0.23405 0.33999 0.33999 0.23405
Total Mole Fraction ('Vap', 'benzene') dimensionless 0.25000 3.1248e-05 0.024624 0.058732 0.17408 0.084499 0.084499 0.084499 0.084499 0.82430 0.82430 0.084499
Total Mole Fraction ('Vap', 'toluene') dimensionless 0.25000 3.1248e-05 0.028601 0.15380 0.038450 0.0088437 0.0088437 0.0088435 0.0088435 0.17570 0.17570 0.0088435
Total Mole Fraction ('Vap', 'hydrogen') dimensionless 0.25000 0.93744 0.33283 0.27683 0.16148 0.18592 0.18592 0.18592 0.18592 1.7561e-08 1.7561e-08 0.18592
Total Mole Fraction ('Vap', 'methane') dimensionless 0.25000 0.062496 0.61394 0.51064 0.62599 0.72074 0.72074 0.72074 0.72074 4.3265e-08 4.3265e-08 0.72074
Temperature kelvin 303.20 303.20 324.51 600.00 771.86 325.00 325.00 325.00 325.00 375.00 375.00 325.00
Pressure pascal 3.5000e+05 3.5000e+05 3.5000e+05 3.5000e+05 3.5000e+05 3.5000e+05 3.5000e+05 3.5000e+05 3.5000e+05 1.5000e+05 1.5000e+05 3.5000e+05
====================================================================================
What is the total operating cost?
operating cost = $ 419008.281895999
For this operating cost, what is the amount of benzene we are able to produce and what purity we are able to achieve? We can look at a specific unit models stream table with the same report() method.
====================================================================================
Unit : fs.F102 Time: 0.0
------------------------------------------------------------------------------------
Unit Performance
Variables:
Key : Value : Units : Fixed : Bounds
Heat Duty : 7346.7 : watt : False : (None, None)
Pressure Change : -2.0000e+05 : pascal : True : (None, None)
------------------------------------------------------------------------------------
Stream Table
Units Inlet Vapor Outlet Liquid Outlet
Total Molar Flowrate Liq mole / second 0.26712 - -
Total Molar Flowrate Vap mole / second 1.0000e-08 - -
Total Mole Fraction ('Liq', 'benzene') dimensionless 0.76595 - -
Total Mole Fraction ('Liq', 'toluene') dimensionless 0.23405 - -
Total Mole Fraction ('Vap', 'benzene') dimensionless 0.084499 - -
Total Mole Fraction ('Vap', 'toluene') dimensionless 0.0088437 - -
Total Mole Fraction ('Vap', 'hydrogen') dimensionless 0.18592 - -
Total Mole Fraction ('Vap', 'methane') dimensionless 0.72074 - -
Temperature kelvin 325.00 - -
Pressure pascal 3.5000e+05 - -
flow_mol_phase Liq mole / second - 1.0000e-08 0.094878
flow_mol_phase Vap mole / second - 0.17224 1.0000e-08
mole_frac_phase_comp ('Liq', 'benzene') dimensionless - 0.66001 0.66001
mole_frac_phase_comp ('Liq', 'toluene') dimensionless - 0.33999 0.33999
mole_frac_phase_comp ('Vap', 'benzene') dimensionless - 0.82430 0.82430
mole_frac_phase_comp ('Vap', 'toluene') dimensionless - 0.17570 0.17570
mole_frac_phase_comp ('Vap', 'hydrogen') dimensionless - 1.7561e-08 1.7561e-08
mole_frac_phase_comp ('Vap', 'methane') dimensionless - 4.3265e-08 4.3265e-08
temperature kelvin - 375.00 375.00
pressure pascal - 1.5000e+05 1.5000e+05
====================================================================================
benzene purity = 0.8242963450787166
Next, let’s look at how much benzene we are losing with the light gases out of F101. IDAES has tools for creating stream tables based on the Arcs and/or Ports in a flowsheet. Let us create and print a simple stream table showing the stream leaving the reactor and the vapor stream from F101.
Units Reactor Light Gases
Total Molar Flowrate Liq mole / second 5.7340e-09 1.0000e-08
Total Molar Flowrate Vap mole / second 2.0320 1.7648
Total Mole Fraction ('Liq', 'benzene') dimensionless 0.63390 0.76595
Total Mole Fraction ('Liq', 'toluene') dimensionless 0.36610 0.23405
Total Mole Fraction ('Vap', 'benzene') dimensionless 0.17408 0.084499
Total Mole Fraction ('Vap', 'toluene') dimensionless 0.038450 0.0088437
Total Mole Fraction ('Vap', 'hydrogen') dimensionless 0.16148 0.18592
Total Mole Fraction ('Vap', 'methane') dimensionless 0.62599 0.72074
Temperature kelvin 771.86 325.00
Pressure pascal 3.5000e+05 3.5000e+05
8 Optimization
We saw from the results above that the total operating cost for the base case was $419,122 per year. We are producing 0.142 mol/s of benzene at a purity of 82%. However, we are losing around 42% of benzene in F101 vapor outlet stream.
Let us try to minimize this cost such that:
we are producing at least 0.15 mol/s of benzene in F102 vapor outlet i.e. our product stream
purity of benzene i.e. the mole fraction of benzene in F102 vapor outlet is at least 80%
restricting the benzene loss in F101 vapor outlet to less than 20%
For this problem, our decision variables are as follows:
Let us declare our objective function for this problem.
Now, we need to unfix the decision variables as we had solved a square problem (degrees of freedom = 0) until now.
Next, we need to set bounds on these decision variables to values shown below:
H101 outlet temperature [500, 600] K
R101 outlet temperature [600, 800] K
F101 outlet temperature [298, 450] K
F102 outlet temperature [298, 450] K
F102 outlet pressure [105000, 110000] Pa
Let us first set the variable bound for the H101 outlet temperature as shown below:
Let us fix the bounds for the rest of the decision variables.
Now, the only things left to define are our constraints on overhead loss in F101, product flow rate and purity in F102. Let us first look at defining a constraint for the overhead loss in F101 where we are restricting the benzene leaving the vapor stream to less than 20 % of the benzene available in the reactor outlet.
Let us add the final constraint on product purity or the mole fraction of benzene in the product stream such that it is at least greater than 80%.
We have now defined the optimization problem and we are now ready to solve this problem.
8.1 Optimization Results
Display the results and product specifications
operating cost = $ 312674.2367537996
Product flow rate and purity in F102
====================================================================================
Unit : fs.F102 Time: 0.0
------------------------------------------------------------------------------------
Unit Performance
Variables:
Key : Value : Units : Fixed : Bounds
Heat Duty : 8370.2 : watt : False : (None, None)
Pressure Change : -2.4500e+05 : pascal : False : (None, None)
------------------------------------------------------------------------------------
Stream Table
Units Inlet Vapor Outlet Liquid Outlet
Total Molar Flowrate Liq mole / second 0.28812 - -
Total Molar Flowrate Vap mole / second 1.0000e-08 - -
Total Mole Fraction ('Liq', 'benzene') dimensionless 0.75463 - -
Total Mole Fraction ('Liq', 'toluene') dimensionless 0.24537 - -
Total Mole Fraction ('Vap', 'benzene') dimensionless 0.032748 - -
Total Mole Fraction ('Vap', 'toluene') dimensionless 0.0032478 - -
Total Mole Fraction ('Vap', 'hydrogen') dimensionless 0.21614 - -
Total Mole Fraction ('Vap', 'methane') dimensionless 0.74786 - -
Temperature kelvin 301.88 - -
Pressure pascal 3.5000e+05 - -
flow_mol_phase Liq mole / second - 1.0000e-08 0.10493
flow_mol_phase Vap mole / second - 0.18319 1.0000e-08
mole_frac_phase_comp ('Liq', 'benzene') dimensionless - 0.64256 0.64256
mole_frac_phase_comp ('Liq', 'toluene') dimensionless - 0.35744 0.35744
mole_frac_phase_comp ('Vap', 'benzene') dimensionless - 0.81883 0.81883
mole_frac_phase_comp ('Vap', 'toluene') dimensionless - 0.18117 0.18117
mole_frac_phase_comp ('Vap', 'hydrogen') dimensionless - 1.1799e-08 1.1799e-08
mole_frac_phase_comp ('Vap', 'methane') dimensionless - 4.0825e-08 4.0825e-08
temperature kelvin - 362.93 362.93
pressure pascal - 1.0500e+05 1.0500e+05
====================================================================================
benzene purity = 0.8188295888412465
Overhead loss in F101
====================================================================================
Unit : fs.F101 Time: 0.0
------------------------------------------------------------------------------------
Unit Performance
Variables:
Key : Value : Units : Fixed : Bounds
Heat Duty : -68347. : watt : False : (None, None)
Pressure Change : 0.0000 : pascal : True : (None, None)
------------------------------------------------------------------------------------
Stream Table
Units Inlet Vapor Outlet Liquid Outlet
Total Molar Flowrate Liq mole / second 1.5819e-12 - -
Total Molar Flowrate Vap mole / second 1.9480 - -
Total Mole Fraction ('Liq', 'benzene') dimensionless 0.57381 - -
Total Mole Fraction ('Liq', 'toluene') dimensionless 0.42619 - -
Total Mole Fraction ('Vap', 'benzene') dimensionless 0.13952 - -
Total Mole Fraction ('Vap', 'toluene') dimensionless 0.039059 - -
Total Mole Fraction ('Vap', 'hydrogen') dimensionless 0.18417 - -
Total Mole Fraction ('Vap', 'methane') dimensionless 0.63725 - -
Temperature kelvin 775.95 - -
Pressure pascal 3.5000e+05 - -
flow_mol_phase Liq mole / second - 1.0000e-08 0.28812
flow_mol_phase Vap mole / second - 1.6598 1.0000e-08
mole_frac_phase_comp ('Liq', 'benzene') dimensionless - 0.75463 0.75463
mole_frac_phase_comp ('Liq', 'toluene') dimensionless - 0.24537 0.24537
mole_frac_phase_comp ('Vap', 'benzene') dimensionless - 0.032748 0.032748
mole_frac_phase_comp ('Vap', 'toluene') dimensionless - 0.0032478 0.0032478
mole_frac_phase_comp ('Vap', 'hydrogen') dimensionless - 0.21614 0.21614
mole_frac_phase_comp ('Vap', 'methane') dimensionless - 0.74786 0.74786
temperature kelvin - 301.88 301.88
pressure pascal - 3.5000e+05 3.5000e+05
====================================================================================
Display optimal values for the decision variables
Optimal Values:
H101 outlet temperature = 500.000 K
R101 outlet temperature = 775.947 K
F101 outlet temperature = 301.881 K
F102 outlet temperature = 362.935 K
F102 outlet pressure = 105000.000 Pa