Research Philippe Nimmegeers

Abstract

Polyurethanes (PU) are widely used in mattresses, upholstery, furniture, automotive, construction, and insulation. They are mostly thermoset foams, made by reacting isocyanates (MDI, TDI, or HDI) with polyols. Their thermoset nature limits mechanical recycling, making chemical recycling crucial for circularity. The resulting aromatic molecules, ureas, amines and polyols from depolymerization have varied physicochemical characteristics, impacting separation during recycling. This doctorate aims to use thermodynamic modeling tools to predict the ease of separating depolymerized PU mixtures. Methods include activity coefficient based models (NRTL, UNIFAC, HANSEN) that are accompanied by computational chemistry methods to optimize the models and fill in unknown gaps. Modeling results will inform engineering software for process design, optimizing recycling for recyclers and informing circular design for PU formulators and recyclers. The focus is primarily on predicting interactions between different polyols used in PU, considering monomer composition, degree of branching, molecular weight distribution, and functionality, to facilitate efficient separations. Later, other constituents are covered in more detail as well. The goal is to provide recyclers and formulators with insights for process optimization and improved circularity of PU materials.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Cunha Ana
• Co-promoter: Nimmegeers Philippe
• Fellow: de Graaf Christophe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

The process of resource extraction takes a significant toll on the environment, climate, biodiversity, and the overall livability of our planet. Through proper processing of end-of-life products and material flows for reintegration into the forward supply chain, defined as circular supply chain management, this impact can be drastically reduced. Circularity considerations, however, are expensive and require the collaboration of various stakeholders, including, among others, manufacturers, customers, recycling plants, and the government. The CIRCUS project aims to develop generic circular supply chain optimization models to facilitate the development and deployment of cost-effective and environmentally friendly circular supply chains. The envisaged models are simple (i.e., avoiding all unnecessary complexity), generic (i.e., applicable within a broad range of industries and circularity strategies), and aligned with a multi-stakeholder reality. As such, we will provide decision-makers at various levels and aiming for different objectives with clear guidance on how to seize benefits and engage in circular supply chain practices.

Researcher(s)

• Promoter: Defryn Christof
• Co-promoter: Nimmegeers Philippe
• Fellow: Langenaeker Alix

Research team(s)

• Engineering Management

Project type(s)

• Research Project

Abstract

Novel electrolyser technologies that improve cost-efficiency through reductions in electricity and component costs will be needed for delivering hydrogen from renewables at scale. In this project we aim to develop a breakthrough photoelectrolysis device that will (a) reduce the electricity demand of clean hydrogen production; (b) eliminate use of critical raw materials (CRM) in electrodes/electrocatalysts; and (c) couple hydrogen generation to valorization of a biomass- derived stream, thus improving technoeconomic performance and circularity. The aim is to deliver plasmon-enhanced, hybrid photoelectrolysis under alkaline conditions for hydrogen generation. Cell voltages will be lowered, first, via replacement of oxygen evolution at the anode with an organic oxidation reaction (OOR) that will offer thermodynamic advantages, benefits associated with component and operational costs and added-value chemicals from bio-waste via selective anodic processes. Second, photoelectrolysis enhanced by plasmon-ENZ (Epsilon Near- Zero) systems will be adopted to reduce cell overpotential and enhance energy efficiency. Third, computationally guided design of CRM-free plasmon-enhanced electrocatalysts will enable delivery of activity and selectivity without reliance on precious and/or scarce metals. We will demonstrate breakthrough improvements relative to state-of-the-art using three key performance indicators defined to accurately reflect trade-offs in energy efficiency and cost arising from the OOR and from materials choices that depart from state-of-the-art, while weighting the benefits of a transition to CRM-free strategies and consequent improvements in criticality. The mainstreaming of technoeconomic and life cycle analysis will guide materials choices to deliver a prototype CRM-free photoelectrolyser at lab scale, and will chart a path to cost-competitive application scenarios for exploitation beyond proof-of-concept. Within this project, the UAntwerp partner will particularly focus on the synthesis of noble metal- free plasmonic nanostructures based on ZrN, and explore new types of photoelectrochemical cell design. In close interaction with the EnvEcon research group, a detailed techno-economic assessment will be performed, which will reveal the best opportunities towards valorization. Unique in the setting of the valorization roadmap is that not only cost reductions in device construction or sales volumes of produced hydrogen will be accounted for, but also profits made by up-conversion of bio-waste streams used a the feed, and environmental and related cost impacts by avoiding the use of critical raw materials.

Researcher(s)

• Promoter: Verbruggen Sammy
• Co-promoter: Bals Sara
• Co-promoter: Nimmegeers Philippe
• Co-promoter: Van Passel Steven

Research team(s)

• Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)

Project type(s)

• Research Project

Abstract

Circular economy strategies are gaining attention within companies to reduce their environmental impact and meet government targets. In this context, companies in different sectors are investigating and implementing different strategies to reuse, repair, refurbish, remanufacture, reuse, recycle and recover end-of-life products, components, parts or materials. Deciding which strategy to choose requires case-specific life cycle and techno-economic assessments, which typically require a lot of data, expertise and time. Furthermore, there is no single quantitative definition of circularity that can be directly used to assess, monitor and optimize the circularity of product designs or value chains. Therefore, there is a need for generic tools/methods that can be used to assess circularity based on generic information that is commonly available. To address this knowledge gap, we present three central hypotheses, in which we argue that energy consumption provides an adequate projection of circularity and that entropy is a valid parameter to move from process-specific assessment methods to more generic state-based assessment methods: Hypothesis 1: The relationship between the embodied energy of materials and products and their carbon footprint is linear. This has already been demonstrated in several studies, Hypothesis 2: The relationship between the embodied energy of materials and their economic value (as raw materials) is linear. This has already been demonstrated by the work of Tim Gutowski and others. Hypothesis 3: The relationship between resource dilution (reciprocal concentration in deposits) and embodied energy of materials is linear. Dilution here can be interpreted directly as entropy, cf. the description above. This has already been demonstrated for metals, while we have calculated a similar relationship for post-consumer packaging waste in preliminary work. Evidence supporting these three hypothesis would for the first time establish a direct and quantitative link between materials circularity and climate change. That way entropy can be used as a proxy for energy expenditure over the life cycle of a material, and in turn for the carbon footprint. We would further provide basic evidence, that can convince companies and policy makers using simple case studies. In this project, we will further demonstrate hypotheses 2 and 3, by focusing on the value versus entropy of waste materials, and by looking at bioresources. As a result, using this framework, waste sorting and (bio-)refining processes can be judged on the performance of individual unit operations rather than only on the end results of a complete plant configuration. The scope for this project will be restricted to different fossil-based polymers and bio-based polymers, to ensure feasibility and complementarity with the group's expertise. The anticipated results will accelerate the deployment and valorization of the novel circularity assessment methodology and make it more accessible to the main target audience, i.e. product and process designers. In this way, the foundations will be laid for a circularity quantification and optimization tool based on generic thermodynamic principles.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Nimmegeers Philippe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

The continuously rising demand for resources is pushing us to exceed the planetary boundaries. At present, methods as life cycle assessment and techno-economic assessment have been proposed to develop sustainable systems and processes. However, these traditional methods do not allow us to predict the sustainability of disruptive technologies starting from a blank canvas, as these rely on very specific information that only becomes available at higher technology readiness levels (TRL) and a background system. Hence, methods are needed that solely rely on generic information available at any TRL. This is exactly what I aim to achieve in this research project: I will create an innovative design-for-sustainability paradigm that can deliver forecasts and can optimize the development of novel processes and systems in view of economic and environmental sustainability at any TRL. To this end, I will connect statistical entropy to generic energy calculations and generic capital cost estimates and I will define multi-objective optimization problem formulations and solution strategies. As validation, three applications will be studied: (i) the design of lignocellulosic biorefineries, (ii) polyolefin plastic waste management and (iii) phosphorous management. The proposed groundbreaking research will open avenues towards my future career as an independent academic principal investigator working on process-based modeling, control and optimization for the development of sustainable systems.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Van Passel Steven
• Fellow: Nimmegeers Philippe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Plastics are an integral part of our daily lives, however, they are difficult to recycle. Nevertheless, the diversity of polymeric materials is still increasing, despite societal and legislative pressure to reduce their complexity. Unfortunately life cycle assessment and techno-economic assessment always start from enthalpic considerations, i.e. material and energy balances, rather than entropic considerations, i.e. product complexity and structure. This leads to the paradoxical situation that we do not know which waste material is of enough high value to recycle taking into account any (future) market conditions, and that we do not exactly know how to produce plastics to optimize the value of post-consumer recyclate. Moreover, the (macro)molecular level, which determines macroscopic properties, is never addressed, although it is well-recognized that industrial polymer synthesis is characterized by significant inter-and intramolecular variations. A linking of polymer reaction eng (PRE; Ghent University expertise) and generic sustainability assessment (SA) methods (University of Antwerp) is thus almost absent but highly recommendable, justifying the scope. We aim at a generic method for the prediction and optimization of the recyclability of economic goods starting at the molecular level. In the long run the method can predict on the fly whether chemical modifications are not only worthwhile application wise but also in view of recyclability.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Nimmegeers Philippe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

To address climate change and environmental degradation, the EU has set objectives with net zero greenhouse gas (GHG) emissions by 2050 to become the first climate-neutral continent. Carbon Capture, Utilization and Storage (CCUS) is expected to be one of the key technological solutions as it allows to address inevitable GHG emissions. To establish CCUS value chains and stimulate investments to ensure adequate scale and availability of the technology, it is crucial to understand, develop and implement measures to prioritize the development of the technologies with the highest potential potential (as well economically). Current state-of-the-art techno-economic and environmental impact assessments of CCUS are limited due to following reasons: (i) heterogeneity in potential CCUS value chains, point sources, capture methods, transport, storage, and utilization, (ii) their dependence on specific information related to background systems of specific technologies, specific geographic conditions and time period, (iii) the current lack of accepted benchmarks, best practices and integrated sustainability assessments for CCUS and (iv) the social dimension that is not addressed in current assessments. This makes current state-of-the-art methods data-intensive and the obtained results very specific. Thus, there is a need for a standardized, harmonized, generic methodological framework to stimulate the design and deployment of economically feasible, environmentally desirable and socially acceptable CCUS value chains. This requires a multidisciplinary and interdisciplinary approach involving expertise from different fields: chemical engineering, economics, sociology, quantitative sustainability assessments, process systems engineering and stakeholders along the value chain. The proposed postdoc challenge is as follows: "How can we create understanding about the levers that are needed to design and deploy economically feasible, environmentally desirable and socially acceptable carbon dioxide capture, transport, utilization and storage (CCUS) value chains ?" The following aspects are expected to be addressed : - Advances beyond the current state-of-the-art research on the sustainability impacts of CCUS. - Provide a harmonized, holistic, integrated prospective/ex-ante sustainability assessment framework on the full CCUS system and CCUS value chains, facilitating development of the most technologically, economically feasible, environmentally desirable and socially acceptable CCUS technologies and value chains. - Involvement of different stakeholders in the CCUS value chains - Reproducibility and honest benchmarking of CCUS technologies - Sound assessments to guide R&D in the most optimal direction and pinpoint those areas of technologies and systems that have the highest potential and where improvement is required.

Researcher(s)

• Promoter: Compernolle Tine
• Co-promoter: Nimmegeers Philippe

Research team(s)

• Engineering Management

Project type(s)

• Research Project

Abstract

The circular economy action plan adopted in March 2020 is one of the main building blocks of the European Green Deal that aims for the EU to become climate neutral by 2050 and to reduce other environmental impacts (e.g. nitrogen pollution, air pollution, biodiversity loss). The circular economy will require the increased utilization of residual streams (e.g. wastes and side streams) by creating new high value products from them. This may include the production of fertilizers, proteins or construction materials from waste streams as well as the substitution of fossil-based plastics by renewable alternatives. However, in pursuing the circular economy, it needs to be ensured that the environmental impacts of the novel goods are indeed lowered or that environmental impacts are not simply swapped between impact domains. In addition, by reusing waste streams new methodological challenges for the environmental assessments emerge including how to account for the impacts of waste generated upstream, what the systemic impact of new value chains based on waste/side stream products is and how to account for the difference in the quality of recyclates as compared to virgin materials. The objective of the MAZE project is to develop novel methods and approaches to improve the (prospective) evaluation of environmental impacts of products in the circular economy. The principal methods to be used in the project are life cycle assessment and material flow analysis. The research will address how upstream impacts of waste products can be accounted for, how product quality can be evaluated in environmental and material flow assessments and subsequently how information can be used in prospective decision making. Methods will be applied to a selected number of biobased materials/products to demonstrate their applicability. Thereby, outcomes of the project are in strategic alignment with the EU's circular economy action plan.

Researcher(s)

• Promoter: Nimmegeers Philippe
• Promoter: Spiller Marc
• Co-promoter: Buyle Matthias
• Co-promoter: Nimmegeers Philippe
• Co-promoter: Spiller Marc

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Plastics are versatile and paramount in our daily lives. However, this versatility makes plastics difficult to recycle due to their complexity in terms of geospatial distribution, substance/monomer/oligomer composition and molecular distribution. This complexity, later referred to as entropic considerations, is barely acknowledged in the traditional, state-of-the-art recyclability and sustainability assessments such as life cycle analysis (LCA) and techno-economic assessment (TEA). And yet, in order to design recyclable and therefore sustainable materials, and implement supporting policy, having this knowledge via an easily accessible methodology is imperative. Polyurethanes (PU) are highly versatile polymeric materials used in a plethora of applications. To date, the main end-of-life waste management steps for PU are incineration and landfilling, with only limited recycling. Therefore, I will study the following research question: "How does the complexity of polyurethanes affect the recyclability of related applications, and how can we quantify this?". In this blue sky small research project, I combine my expertise on statistical entropy analysis and generic recyclability predictions with the expertise on chemical recycling of plastics at the iPRACS research team to: (i) develop a generic methodology for the evaluation of the recyclability of plastic waste including information on the compositional complexity, complexity in terms of geospatial distribution of products over society and monomer composition and molecular distributions based on MSEA and (ii) validate the methodology by quantifying the limitations to the recyclability of PU. The resulting fully validated recyclability assessment paradigm will serve as a stepping stone for my independent research track. The proposed research project could give sufficient demonstration of the methodology to make it accessible for future applications and projects.

Researcher(s)

• Promoter: Nimmegeers Philippe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project