François Maréchal

François Maréchal
École Polytechnique Fédérale de Lausanne | EPFL · Energy polis

Ph D, Ms Chemical engineering

About

559
Publications
113,580
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Introduction
My field of research is Energy Systems Engineering. My research interests are to develop computer aided methods that help engineers to identify energy savings and efficiency improvement in processes and energy conversion systems. These methods combine thermodynamic analysis, process modelling, process integration and optimization techniques and are validated on real scale cases from the industry.
Additional affiliations
January 2001 - April 2013
École Polytechnique Fédérale de Lausanne
Position
  • MER

Publications

Publications (559)
Presentation
Full-text available
cole Polytechnique Fédérale de Lausanne  Large heating/cooling demands  Waste heat is an important byproduct  More stringent regulations (> 100 EUR/t CO2)  Need for decarbonization  NetZero 2050 roadmap IEA: 15-30% heating demand of light industries  Power-togas for grid-scale energy storage Multi-time integration of industrial complexes and...
Conference Paper
Full-text available
The energy integration of industrial complexes and urban agglomerations has many benefits in terms of rational energy use and reduced environmental impact, especially during scenarios of supply chain uncertainty and volatile market prices. In fact, the diversification of the energy inputs along with the waste heat upgrading through the implementati...
Article
Solid oxide fuel cell-gas turbine (SOFC-GT) hybrid system is an efficient and potential method for distributed energy supply. The system layout, component operating parameters, system-level heat integration, component selection and design, etc., determine the system performance. To further improve the performance and achieve zero CO2 emissions, a a...
Conference Paper
The pursuit of alternative energy sources for the nitrogen fertilizers sector has recently earned renewed interest due to increasing concerns regarding the world dependence on non-renewable energy resources and also motivated by the more stringent environmental regulations. The decarbonization of this sector, responsible for 2% of the global energy...
Presentation
Complex industrial processes are often modelled using flow-sheeting software, wherein any change in inputs may require significant computation time. For studying the integration of complex processes into industrial clusters and explore synergies among them, computationally inexpensive surrogate models proved to be a smart solution. This study devel...
Conference Paper
Heat pumps will play an important role in cutting down fuel consumption and increasing the efficiency of industrial processes, aiming to decarbonize heating applications, especially at high temperature. However, many challenges may arise when defining the best operating conditions and arrangements of those devices, and the effect of the energy inpu...
Conference Paper
Complex industrial processes are often modelled using flow-sheeting software, wherein any change in inputs may require significant computation time. For studying the integration of complex processes into industrial clusters and explore synergies among them, computationally inexpensive surrogate models proved to be a smart solution. This study devel...
Presentation
In this work, the conventional scenario of the black liquor (BL) concentration and combustion is compared with the BL upgrading gasification process for ammonia production. The chemical processes synthesis, modeling and simulation are performed by using Aspen Plus® software. The determination of the heat recovery and the solution of the energy inte...
Conference Paper
In this work, the conventional scenario of the black liquor (BL) concentration and combustion is compared with the BL upgrading gasification process for ammonia production. The chemical processes synthesis, modeling and simulation are performed by using Aspen Plus® software. The determination of the heat recovery and the solution of the energy inte...
Article
Full-text available
When it comes to residential buildings, there are several stochastic parameters, such as renewable energy production, outdoor air conditions, and occupants' behavior, that are hard to model and predict accurately, with some being unique in each specific building. This increases the complexity of developing a generalizable optimal control method tha...
Article
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The conventional configuration of a pulp mill, in which black liquor is concentrated and burnt, is compared with the upgrading gasification routes for methanol (MeOH) or dimethyl ether (DME) co-production. To this end, various exergy-based and environmental impact indicators are assessed in the light of different utility supply scenarios. The combi...
Article
The use of renewable energy sources has been promoted with concern about limited fossil fuels and increased environmental impact. Empty fruit bunch (EFB), which is a valuable biomass residual from palm oil milling processes, is one of the most promising renewable energy sources that can be used to increase the monetary value of EFB through the pyro...
Article
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Electricity markets are currently experiencing a period of rapid change. The intermittent nature of renewable energy is disrupting the conventional methods used in operational planning of the electrical grid, causing a shift from a day-ahead forecast policy to a real-time pricing of delivered electric power. A path towards a more renewable, robust...
Article
A large deployment of energy storage solutions will be required by the stochastic and non-controllable nature of most renewable energy sources when planning for higher penetration of renewable electricity into the energy mix. Various solutions have been suggested for dealing with medium-and long-term energy storage. Hydrogen and ammonia are two of...
Article
Integrated methanol synthesis and methanol-to-olefin systems are considered attractive and promising technologies to produce light olefins from syngas derived from biomass feedstock. In this study, a flowsheet model of a proposed system was developed and employed for system design and analysis. The system consists of four main parts: a methanol syn...
Article
The design of efficient energy systems, through the development of new technologies and the improvement of current ones, requires the use of rigorous process synthesis methods for generating and analysing design alternatives. We introduce a digital twin of process and energy system design that interactively translates needs and preferences of decis...
Article
In light of the energy transition, it becomes a widespread solution to decentralize and to decarbonize energy systems. However, limited transformer capacities are a hurdle for large-scale integration of solar energy in the electricity grid. The aim of this paper is to define a novel concept of renewable energy hubs and to optimize its design strate...
Chapter
In superstructure optimization of processes and energy systems, the design space is defined as the combination of unit considerations, process conditions and model parameters that might be subjected to uncertainty. Most of the time, decision makers are not looking for a single best solution, but rather are interested in analyzing a set of Pareto-op...
Chapter
Optimal design and scheduling of energy systems with a high share of renewables is a complex and computationally demanding task. The mismatch of supply and demand of energy requires the consideration of timeseries with a granularity of a few minutes, which is in contrast to the lifetime of the system of multiple decades. This paper proposes an algo...
Chapter
Municipal solid waste is a mixture of urban and industrial waste, consisting of biodegradable fractions, such as food waste, waste wood or paper, but also fossil-based fractions, among which plastics, textiles, metals, glass and aluminum. Depending on the type of waste and recovery technique, biogas, biofuels, heat, electricity and metals, are poss...
Chapter
Membrane separation may substitute conventional energy intensive technologies, and it could have cost benefits and lower environmental footprints. Several membrane processes have been developed to achieve higher purity and recovery of products. This study uses a generic membrane superstructure (or system) that facilitates all possible inter- and in...
Article
Full-text available
Simulation-based optimization models are widely applied to find optimal operating conditions of processes. Often, computational challenges arise from model complexity, making the generation of reliable design solutions difficult. We propose an algorithm for replacing non-linear process simulation models integrated in multi-level optimization of a p...
Article
The design of user-level integrated energy systems is challenged by a variety of combinations of energy converters, complex cascade utilization of multiple energy flows, as well as sequential matching between stochastic energy resources and periodic energy demands. These issues can be addressed by an optimal energy-hub based planning framework cons...
Article
Full-text available
The expected increase of the penetration of distributed renewable energy technologies into the electricity grid is expected to lead to major challenges. As a main stakeholder, authorities often lack the appropriate tools to frame and encourage the transition and monitor the impact of energy transition policies. This paper aims at combining relative...
Article
The biogas needs to be reformed before electro-chemical conversion in the solid-oxide fuel cell, which can be promoted efficiently with wise thermal management and reforming conditions. To ensure the system safety and catalysts durability, additional mineral-bearing water and carbon deposition should be avoided. This paper conducted a detailed biog...
Article
Full-text available
Biomass, bioenergy and negative emission technologies are inherent to the future design of energy systems. Urban clusters have a growing demand for fuel, heat and electricity, which is both a challenge and an opportunity for biomass-based technologies. Their deployment should meet demand, while minimizing environmental impact and staying cost-compe...
Conference Paper
Despite numerous energy system optimization models for long-term planning on a national level, the plausibility assessment of suggested pathways is seldom involved taking into consideration: 1) the impact of existing capacity stocks on the future energy system; 2) self-corrective functionality if the pathway diverges from the projected ones a poste...
Article
Full-text available
With a growing energy demand in a carbon-constrained society, fuels cells powered by renewable fuels, and specifically solid waste, are seen as interesting contributors to the energy portfolio. The alternative energy industry needs to reduce costs, enhance efficiency, and demonstrate durability and reliability to be economically feasible and attrac...
Article
Full-text available
Ancient Romans called urbs the set of buildings and infrastructures, and civitas the Roman citizens. Today instead, while the society is surfing the digital tsunami, urbs and civitas tend to become much closer, almost merging, that we might attempt to condensate these into a single concept: smart grid. Internet of things, artificial intelligence, b...
Article
Full-text available
This study investigates the technical and economic feasibility of replacing throttling valves with smale-scale, oil-free turbomachinery in industrial steam networks. This is done from the perspective of the turbomachine, which has to be integrated into a new or existing process. The considered machines have a power range of P=[0.5,…,250 kW] and hav...
Article
Full-text available
Electrical energy storage systems are indispensable for the electrical grid with high penetration renewables. Reversible solid-oxide cell stack based power-to-x-to-power systems, which can switch between power generation and power storage, can achieve a high round-trip efficiency and are technology neutral for, e.g., hydrogen, methane, methanol, am...
Article
Full-text available
Electricity production and consumption must be balanced for the electrical grid. However, the rapidly growing intermittent power sources are now challenging the supply-demand balance, leading to large flexibility needs for grid management. The plant integrating biomass gasification and reversible solid-oxide cell stacks can be potential means of fl...
Article
Lignocellulosic biomass is a potential renewable resource for production of high-value, sustainable products. Furfural is among the important bio-based chemicals in biorefineries. However, the conventional process of furfural production using a reaction-separation network entails low product yield but high fixed and operating costs owing to the com...
Article
Full-text available
In the context of increasing concern for anthropogenic CO 2 emissions, the residential building sector still represents a major contributor to energy demand. The integration of renewable energy sources, and particularly of photovoltaic (PV) panels, is becoming an increasingly widespread solution for reducing the carbon footprint of building energy...
Article
Urea is widely used in agriculture, industry, and food, while it is also a potential fuel. Large-scale urea production relies on fossil fuels, thus there is a strong need for green urea given the increasing penetration of renewable energy sources. A potential alternative is biomass-to-urea; however, it cannot fully convert the biomass carbon into u...
Article
Full-text available
The Solid-oxide fuel cell is a highly efficient prime mover for biogas conversion, but a part of biogas needs to be reformulated externally to facilitate the electrochemical conversion, easy control of reforming conditions, and thermal management of the stack. Carbon deposition and external mineralcarrying water should be avoided to ensure the dura...
Chapter
In this contribution, we propose an algorithm for replacing non-linear process simulation integrated in multi-level optimization of an energy system superstructure with surrogate models. With our approach, we demonstrate that surrogate models are a valid tool to replace simulation problems in multi-stage optimization frameworks and enable the impro...
Chapter
Failure in appropriately managing complex municipal solid waste systems in general and waste plastics in particular negatively affects public health and environment. A decision-making tool incorporating concepts of logistics and supply chain, considering different types of waste was developed. A multi-objective, multi-period mixed-integer linear pr...
Article
Full-text available
Industrial process integration based on mixed integer linear programming has been used for decades to design and improve industrial processes. The technique has later been extended to solve multi-period and multi-scale problems for the design of urban energy systems. Assistance is indeed required for the elaboration of coordinated investment schedu...
Article
Check our latest paper out about bioenergy routes using the exergy concept as an indicator for comparing the quality of the energy conversion processes. If you are interested you could access the paper here: https://authors.elsevier.com/a/1bLgk3iH4BmsJ (free access until August 24, 2020) -- Currently, electricity generation and second-generation et...
Article
Full-text available
Decarbonization gained prominence with the witnessed rise of temperature over recent years, particularly in the aftermath of the adoption of the Paris agreement for limiting the temperature increase within 2°C until 2050. Biogenic resources are explicitly indicated as carbon-neutral from Life Cycle Assessment perspective by the IPCC, shedding light...
Article
Full-text available
Biomass-to-electricity or-chemical via power-to-x can be potential flexibility means for future electrical grid with high penetration of variable renewable power. However, biomass-to-electricity will not be dispatched frequently and becomes less economically-beneficial due to low annual operating hours. This issue can be addressed by integrating bi...
Article
Full-text available
Wastewater treatment and sludge disposal are responsible for considerable costs and emissions in a global scale. With population and urbanization growing, tackling the rational and efficient use of energy while fulfilling the desired effluent standards are imperative. In this work, a superstructure-based approach is designed to incorporate alternat...
Article
A R T I C L E I N F O Keywords: Solid-oxide fuel cell Proton exchange membrane fuel cell Battery Hybrid power systems Off-grid energy supply Electrical mobility A B S T R A C T The global demand for fossil fuels in the transportation sector is increasing rapidly due to the continuous growth of internal combustion engine vehicles. This leads to seve...
Conference Paper
Distric Energy System (DES) represents a promising opportunity to improve energy efficiency and boost the decarbonization of the European energy sector. If most of the studies focus on small consumers typically located within urban areas, large energy users like hospitals, university campuses or airports, constitute complex and unique systems with...
Conference Paper
The Paris Agreement 2015 is a historic initiative taken by the global community to fight against climate change and steer the world towards clean energy transition and deep decarbonization. Switzerland has developed the Energy Strategy 2050 which is a strategic policy package for realizing the transition towards a low-carbon economy. Energy efficie...
Article
Full-text available
Data are essential to urban building energy models and yet, obtaining sufficient and accurate building data at a large-scale is challenging. Previous studies have highlighted that the data impact on urban case studies has not been sufficiently discussed. This paper addresses this gap by providing an analysis of the impact of input data on building...
Chapter
To address the large energy consumption of microalgae dewatering and to increase revenues from microalgae, a novel process for the prior sustainable extraction of carotenoids from wet microalgae biomass is proposed. Carotenoid-rich fraction as a co-product would be extracted prior to its further use for biofuel conversion. Different solvents rangin...
Article
Full-text available
The increasing penetration of variable renewable energies poses new challenges for grid management. The economic feasibility of grid-balancing plants may be limited by low annual operating hours if they work either only for power generation or only for power storage. This issue might be addressed by a dual-function power plant with power-to-x capab...
Article
Thermochemical biomass-to-fuel conversion requires an increased hydrogen concentration in the syngas derived from gasification, which is currently achieved by water–gas-shift reaction and CO2 removal. State-of-the-art biomass-to-fuels convert less than half of the biomass carbon with the remaining emitted as CO2. Full conversion of biomass carbon c...
Article
In this study, the performance of high-purity hydrogen production through the sorption-enhanced chemical looping gasification (SECLG) process, involving a gasifier, calciner, and air reactor, was investigated. In this process, the biomass feedstock was wood residue, and steam, calcium oxide (CaO), and nickel oxide (NiO) were used as a gasifying age...
Chapter
The use of supercritical CO2 (SC–CO2) as a solvent for the extraction of vanillin from organosolv media was proposed and evaluated. The use of sugarcane bagasse as a biomass source to product diversification has been gaining much attention recently and it is a very promising research topic. From sugarcane bagasse, it is already produced fuels as 2G...
Chapter
This work investigates a novel approach for turmeric rhizomes valorization for the obtaining of microparticles composed of curcuminoids ethanolic extract and fractionated volatile oils, using compressed carbon dioxide as an antisolvent and the recovery of phenolic compounds and carbohydrates with pressurized hot water. In addition, a cheap and vers...
Chapter
This chapter discusses the recent (2013–2018) applications on the use of supercritical CO2 (SC–CO2) antisolvent for micronization, coprecipitation, and fractionation of high-value products for the food, cosmetic, and pharmaceutical industries, most focusing on the applications of integrated techniques on the biorefining of plant matrices into marke...
Chapter
The use of supercritical CO2 (SC–CO2) antisolvent for micronization, coprecipitation, and fractionation of high-value products for biorefining of plant matrices into marketable products has been a promising and increasing research topic. These SC–CO2 antisolvent processes are able to microencapsulate many materials that are difficult to treat with...
Chapter
This chapter proposes an innovative biorefinery conceptual process for the production of carotenoids from microalgae using lignocellulose-based biorefinery products and/or by-products and pressurized fluids. The extraction process, which can be done also with microalgal biomass with high content of moisture avoiding high-cost downstream processes,...
Preprint
Ancient Romans called 'urbs' the set of buildings and infrastructures, and 'civitas' the Roman citizens. Today instead, while the society is surfing the digital tsunami, 'urbs' and 'civitas' tend to become much closer, almost merging, that we might attempt to condensate these into a single concept: 'smart grid'. Internet of things, artificial intel...
Article
Full-text available
This research presents a mathematical formulation for optimizing integration of complex industrial systems from the level of unit operations to processes, entire plants, and finally to considering industrial symbiosis opportunities between plants. The framework is constructed using mixed-integer linear programming (MILP) which exhibits rapid conver...
Chapter
Sustainability Assessment of Urban Systems - edited by Claudia R. Binder March 2020
Article
Full-text available
With rising concerns about emissions from shipping, fuel cells are expected to take an important role in ship propulsion. In particular, solid oxide fuel cells (SOFC) offer high efficiency with the possibility of combined heat and power production. In this paper, we investigate energy, cost, and emission savings on ships resulting from the use of S...