Superstructure Optimization with OUTDOOR: Brewer's Spent Grain Case Study

This repository contains scripts and data used to perform techno-economic and environmental optimization of biorefinery configurations based on Brewer’s Spent Grain (BSG), using the OUTDOOR (Open Superstructure Modeling and Optimization Framework).

OUTDOOR is a tool to construct superstructure optimization models and solve them using MILP solvers.

The project focuses on evaluating different processing pathways and product portfolios through:

• Single-objective optimization
• Multi-objective optimization (economic vs environmental trade-offs)
• Process cascade analysis

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Main Components

1. Superstructure Modeling
   Predefined superstructures are stored as serialized .pkl files in the superstructures/ directory, representing different processing configurations for BSG valorisation.

2. Optimization Workflows
   The scripts in the code/ folder allow running:

• Single-objective optimization (e.g. cost or environmental impact)
• Multi-objective optimization (Pareto front analysis)
• Cascade-based process evaluations

3. Results Processing
   Simulation outputs are stored as .outdr files and post-processed into:

• Process flowsheets
• Superstructure visualizations
• Economic and environmental indicators (e.g. CAPEX, OPEX, GWP)

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Related Publication

This repository contains the code associated with the following publication:

Andrea Penedo et al. (2026).
"Pathway development for brewer’s spent grain valorization using multi-objective optimization".
Waste Management.
https://doi.org/10.1016/j.wasman.2026.115558

If you use this code, please cite the associated publication.