Overview
The overall goal of our research is to develop safe, economically and environmentally sustainable chemical and biological processes through the synergistic use of advanced computational modelling and optimisation methods and process data. Our vision of process systems engineering has a strong focus on rigorous computation to predict the performance at scale of both existing and novel technology and empower decision-making, and we work in close collaboration with experimentalists. We furthermore develop software tools that implement these methods to ensure their dissemination (https://github.com/omega-icl).
The principal areas of our research are currently threefold, with about identical emphasis on each area.
Analysis, optimization and Control of UNCERTAIN PROCESSES

This entails making optimal decisions, either off-line or in real-time, despite limited or uncertain process knowledge. A particular focus has been on set-theoretic approaches for rigorous uncertainty propagation in nonlinear dynamic systems, including their implementation into software packages (MC and CRONOS). This unique capability can be exploited in algorithms to provide global optimality or robustness certificates. Another main focus has been on real-time optimization methods that rely on process data and feedback to drive an uncertain system to optimality. We have recently set out to extend this paradigm by embedding machine learning to compensate for the lack of physical process understanding.
Recent papers:
- Rio-Chanona EAD, Petsagkourakis P, Bradford E, Modifier adaptation meets Bayesian optimization and derivative-free optimization, arXiv:2009.08819v1 , 2020,
- Sun M, Villanueva ME, Pistikopoulos EN, Methodology for robust multi-parametric control in linear continuous-time systems, Journal of Process Control 73:58-74, 2019 ,
- Houska B, Chachuat B, Global optimization in Hilbert space, Mathematical Programming 173:221-249, 2019
- Houska B, Li JC, Chachuat B, Towards rigorous robust optimal control via generalized high-order moment expansion, Optimal Control Applications & Methods 39:489-502, 2017
- Peric ND, Villanueva ME, Chachuat B, Sensitivity analysis of uncertain dynamic systems using set-valued integration, SIAM Journal on Scientific Computing 39:A3014-A3039, 2017
- Villanueva ME, Quirynen R, Diehl M, Robust MPC via min-max differential inequalities, Automatica 77:311-321, 2017 ,
- Chachuat B, Houska B, Paulen R, Set-theoretic approaches in analysis, estimation and control of nonlinear systems, IFAC-PapersOnLine 48(8):981-995, 2015 ,
- Houska B, Villanueva ME, Chachuat B, Stable set-valued integration of nonlinear dynamic systems using affine set-parameterizations, SIAM Journal of Numerical Analysis 53:2307-2328, 2015
- Villanueva ME, Houska B, Chachuat B, Unified framework for the propagation of continuous-time enclosures for parametric nonlinear ODEs, Journal of Global Optimization 62:575-613, 2014
Design of Multiscale Systems

This involves the transformation of trial-and-error practice for designing complex processes into systematic methods and tools. Our approach has relied on the combination of detailed process modelling with economic / environmental life-cycle assessment and risk management. The use of superstructure-based optimisation offers a natural and powerful framework in this context, but it remains a formidable computational challenge due to the combinatorial and nonlinear nature of these problems (MINLP) and the presence of uncertainty. On-going applications in our group have now widened to polygeneration from natural resources (wastewater, algal biomass, sugarcane, natural gas), catalytic CO2 conversion systems (methanol, higher hydrocarbons), and more recently vaccine manufacturing.
Recent papers:
- Mutran VM, Ribeiro CO, Nascimento CO, Risk-conscious optimization model to support bioenergy investment in the Brazilian sugarcane industry, Applied Energy 258:1-15, 2020 ,
- Uribe-Rodriguez A, Castro PM, Gonzalo G-G, Global optimization of large-scale MIQCQPs via cluster decomposition: Application to short-term planning of an integrated refinery-petrochemical complex, Computers & Chemical Engineering 140:106883, 2020 ,
- Baqeel H, Diaz I, Tulus V, Role of life-cycle externalities in the valuation of protic ionic liquids – a case study in biomass pretreatment solvents, Green Chemistry 22:3132-3140, 2020 ,
- Rodríguez-Vallejo DF, Guillén-Gosálbez G, Chachuat B, What is the true cost of producing propylene from methanol? the role of externalities, ACS Sustainable Chemistry & Engineering 8:3072-3081, 2020
- Rodríguez-Vallejo DF, Galán-Martín Á, Guillén-Gosálbez G, Data envelopment analysis approach to targeting in sustainable chemical process design: Application to liquid fuels, AIChE Journal 65(7):e16480, 2018 ,
- Graciano JEA, Chachuat B, Alves RMB, Enviro-economic assessment of thermochemical polygeneration from microalgal biomass, Journal of Cleaner Production 203:1132-1142, 2018
- Puchongkawarin C, Gomez-Mont C, Stuckey DC, Optimization-based methodology for the development of wastewater facilities for energy and nutrient recovery, Chemosphere 140:150-158, 2015 ,
Process ModelLING and Model Development Tools

This entails constructing predictive mathematical models for novel process technology via the combination of mechanistic knowledge and process data. Our approach aims to strike the right balance between development effort, run-time complexity, and extrapolability. We have pioneered novel methods to support such model development: global optimisation and set-membership estimation (C package CRONOS), and more recently Bayesian estimation (python package DEUS) and optimal experiment design (python package pyDex). Another area of research is hybrid modelling, which combines parametric and nonparametric submodels based on different knowledge sources.
Recent papers:
- Kusumo KP, Gomoescu L, Paulen R, Bayesian approach to probabilistic design space characterization: a nested sampling strategy, Industrial & Engineering Chemistry Research 59:2396-2408, 2019 ,
- Bernardi A, Gomoescu L, Wang J, Kinetic Model Discrimination for Methanol and DME Synthesis using Bayesian Estimation, IFAC-PapersOnLine 52(1):335-340, 2019 ,
- Peric N, Paulen R, Villanueva ME, Set-membership nonlinear regression approach to parameter estimation, Journal of Process Control 70:80-95, 2018 ,
- Pitt JA, Gomoescu L, Pantelides CC, Critical assessment of parameter estimation methods in models of biological oscillators, IFAC-PapersOnLine 51(19):72-75, 2018 ,
- Quek V, Shah N, Chachuat B, Modeling for design and operation of high-pressure membrane contactors in natural gas sweetening, Chemical Engineering Research and Design 132:1005-1019, 2018
- Chachuat B, Houska B, Paulen R, Set-theoretic approaches in analysis, estimation and control of nonlinear systems, IFAC-PapersOnLine 48(8):981-995, 2015 ,
- Bernard O, Mairet F, Chachuat B, Modelling of Microalgae Culture Systems with Applications to Control and Optimization, Advances in Biochemical Engineering/Biotechnology 153:59-87, 2016
- Paulen R, Villanueva ME, Chachuat B, Guaranteed parameter estimation of non-linear dynamic systems using high-order bounding techniques with domain and CPU-time reduction strategies, IMA Journal of Mathematical Control & Information 33(3):563-587, 2015
- Nikolaou A, Bernardi A, Meneghesso A, A model of chlorophyll fluorescence in microalgae integrating photoproduction, photoinhibition and photoregulation, Journal of Biotechnology 194:91-99, 2014 ,