FeOs-CAMPD

Computer-aided molecular and process design based on the FeOs framework.

The package provides infrastructure to perform a computer-aided molecular and process design. It consists of

• Implementation of a custom outer-approximation algorithms to solve the resulting MINLP
• Molecular representations (group counts (CoMT-CAMD) and molecule superstructures)
• Property models (PC-SAFT and (heterosegmented) gc-PC-SAFT)

The underlying NLP subproblems are solved using IPOPT via the ipopt-ad crate. For the solution of th MILP master problems, the solver is linked to the good_lp crate that offers a common interface to various open-source MILP solvers.

Installation

Rust

Just add the dependency to your Cargo.toml

feos-campd = "0.3"

Usage

The following sections demonstrates the usage of the framework, for the API details, check out the documentation.

Molecular representation

// define the molecular representation using a molecule superstructure
let molecule = SuperMolecule::alkane(min_size, size);
// or a combination of superstructures
let molecule = SuperMolecule::non_associating(min_size, size);
// or use group and structure definitions for CoMT-CAMD
// (currently not further customizable)
let molecule = CoMTCAMD;

Property model

// The property model for heterosegmented gc-PC-SAFT is not customizable. It does not include association.
let property_model = GcPcSaftPropertyModel;
// For homosegmented PC-SAFT, the group parameters can be passes as arguments
// and it is available as the full model
let property_model = PcSaftPropertyModel::full("rehner2023_homo.json", Some("rehner2023_homo_binary.json"));
// or non-associating (ignoring all associating groups)
let property_model = PcSaftPropertyModel::non_associating("rehner2023_homo.json", Some("rehner2023_homo_binary.json"));

Process model

//To define a process model in Rust, implement the `ProcessModel` trait for your struct.
impl<E: TotalHelmholtzEnergy<N: ...>> ProcessModel<E, N_X: ..., N: ...> for YourModel {
    fn variables(&self) -> [ContinuousVariable; N_X] {
        [
            ContinuousVariable::new(..., ..., ...),
            ...
        ]
    }

    fn constraints(&self) -> Vec<GeneralConstraint> {
        vec![
            GeneralConstraint::Inequality(..., ...),
            GeneralConstraint::Equality(...),
            ...
        ]
    }

    fn evaluate<D: DualNum<f64> + Copy>(
        &self,
        eos: &HelmholtzEnergyWrapper<E, D, N>,
        chemical_records: [&ChemicalRecord<D>; N],
        x: [D; 3],
    ) -> EosResult<(D, Vec<D>)> {
        ...
    }
}

Optimization problem

// combine molecular representation, property model, and process model in an optimization problem
let campd = IntegratedDesign::new(molecule, property_model, process);

// and pass it to the outer approximation solver
let solver = OuterApproximation::new(&campd);

// to determine a ranking of the optimal molecules for a pur component
solver.solve_ranking(y0, highs, runs, options);
// where highs can be replaced with any of the other MILP solvers provided by the good_lp crate.

Molecular representations and property models can be combined according to:

	PC-SAFT	gc-PC-SAFT
CoMTCAMD	yes	no
SuperMolecule	yes	yes

Cite us

If you find FeOs-torch useful for your own research, consider citing our publication from which this library resulted.

@article{rehner2023molecule_superstructures,
  author = {Rehner, Philipp and Schilling, Johannes and Bardow, André},
  title = {Molecule superstructures for computer-aided molecular and process design}
  journal = {Molecular Systems Design & Engineering},
  volume = {8},
  issue = {4},
  number = {12},
  pages = {488-499},
  year = {2023}
}