Products, Environment, and Processes - ULiège

In the PEPs group, we are active in the fields of (bio-)chemical reaction engineering, thermal and mechanical unit operations, process simulation, low carbon energy systems, and sustainable development. This includes the corresponding fundamentals, especially mass and energy transfers, and multi-phase fluid dynamics.

A strength of our approach is to link the different scales in time and space:

• Starting from microscopic and even molecular level

• Having a strong focus on the equipment level in both experiments and modeling

• Reaching up to the simulation of entire processes

• And evaluating the preferred large-scale deployment pathway.

This allows us to reliably describe and optimize equipment performance based on physically sound modeling, which even includes extrapolation beyond the region of experiments. These tools permit knowledge-based optimization of equipment design and operation parameters, as a basis for safe, sustainable, and profitable scale-up of the processes. Indeed, the simulation of entire processes together with Life Cycle Assessment (LCA) as eco-design support guides optimization at the process level, where both economic and environmental parameters are included in the evaluation.

Experimental infrastructure is available for model development and validation, covering a wide range of applications, such as studying hydrodynamics in various equipment including trajectography, following the microstructure of materials and systems during their processing, especially in a product-oriented engineering approach with (micro-)tomography, lab-scale measuring devices for characterizing the behavior of drops and dispersions, as well as pilot-plant scale equipment for various unit operations like drying and distillation. Additionally, adequate chemical analysis equipment is used to determine gas and liquid phase compositions, including various chromatography and X-ray devices.

The future perspective of our research – besides further development of our fundamental methods – is to prepare chemical-engineering design tools for the future. Thus, our current research topics aim at allowing safe design of sustainable chemical and biobased processes, where process-specific material and energy transformations imply properties changes in the systems such as increased viscosity, posing challenges to the chemical engineer. Similarly, recycling used materials such as the recovery of phosphorus from sewage sludge or the separation of rare earth elements in urban mining creates new and challenging engineering tasks. In particular, both main and alternative routes need to be evaluated and compared for sustainability, which can be done with the methods we design.

The majority of our methods and applications are developed in cooperation or at least in close contact with industry, including essentially all major chemical companies and a variety of local and European SMEs.

Main Topics

• Life cycle assessment: Determination of the environmental impact associated with products or processes, support to ecodesign, implementation of environmental product declarations.

• Sludge management: Optimization of wastewater sludge treatment from conditioning and dewatering to drying.

• Drying of materials: Study of the drying kinetics and textural changes of materials using several drying technologies and advanced characterization tools such as X-ray microtomography to follow shrinkage and cracks.

• Solvent and reactive extraction: Develop and validate a design tool for extraction columns based on the drop-based simulation of the columns, where the parameters of the drop models are determined from lab experiments.

• Coalescence, liquid-liquid phase separation, and settlers: Settler design based on single-drop modeling, where the coalescence parameters are determined from a lab-scale settling experiment.

• Exergetic evaluation and advanced thermodynamic modeling: Exergo-economic comparison of entire process routes and individual process steps is performed, especially for bio-based substances, advanced thermodynamic models are derived.

• Reactor design: Experimental characterization and modeling of flow and mass transfer in stirred tank and packed bed (bio)reactors. Modeling of their global performances. Scale-up and scale-down models.

• Advanced experimental techniques: Development and adaptation of noninvasive visualization techniques to characterize hydrodynamics and mass transfer in (bio)reactors.

• Product-oriented engineering: Fabrication of porous polymer materials with controlled end-use properties based on the mastering of their microstructure through an optimal selection of the fabrication conditions.

• CO2 capture: Experimental study of solvent stability and optimization of the post-combustion CO2 capture process for emissions reduction in large industries and power plants. Negative CO2 emissions with air capture and bio-CCS.

• Power-to-fuel: Integration of CO2 capture with water electrolysis and synthesis of liquid fuels whose high energy density allows for long-term energy storage from variable renewables.

• Process simulation, optimization, and economic evaluation: Steady-state and dynamic modeling of large and complex processes to evaluate and improve their energy efficiency, environmental sustainability, and financial viability.