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François Maréchal  - - - 
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Zlatina Dimitrova

11 shared publications

PSA Groupe, Research and Innovation Department, 78943 Vélizy-Villacoublay, France

Publication Record
Distribution of Articles published per year 
(2003 - 2019)
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Article 0 Reads 0 Citations A Holistic Methodology for Optimizing Industrial Resource Efficiency Maziar Kermani, Ivan D. Kantor, Anna S. Wallerand, Julia Gra... Published: 05 April 2019
Energies, doi: 10.3390/en12071315
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Efficient consumption of energy and material resources, including water, is the primary focus for process industries to reduce their environmental impact. The Conference of Parties in Paris (COP21) highlighted the prominent role of industrial energy efficiency in combating climate change by reducing greenhouse gas emissions. Consumption of energy and material resources, especially water, are strongly interconnected and, therefore, must be treated simultaneously using a holistic approach to identify optimal solutions for efficient processing. Such approaches must consider energy and water recovery within a comprehensive process integration framework which includes options such as organic Rankine cycles for electricity generation from low–medium-temperature heat. This work addresses the importance of holistic approaches by proposing a methodology for simultaneous consideration of heat, mass, and power in industrial processes. The methodology is applied to a kraft pulp mill. In doing so, freshwater consumption is reduced by more than 60%, while net power output is increased by a factor of up to six (from 3.2 MW to between 10–26 MW). The results show that interactions among these elements are complex and therefore underline the necessity of such comprehensive methods to explore their optimal integration with industrial processes. The potential applications of this work are vast, extending from total site resource integration to addressing synergies in the context of industrial symbiosis.
Article 0 Reads 1 Citation Trade-off designs and comparative exergy evaluation of solid-oxide electrolyzer based power-to-methane plants Ligang Wang, Johannes Düll, François Maréchal, Jan Van Herle Published: 01 April 2019
International Journal of Hydrogen Energy, doi: 10.1016/j.ijhydene.2018.11.151
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Solid-oxide electrolyzer (SOE) based power-to-methane (PtM) system can efficiently store surplus renewable power into synthesis natural gas by electrolysis and methanation. The system performance depends on the operating point of the electrolyzer and system design, particularly the heat exchanger network. In this paper, we investigate a SOE based PtM plant with a fixed-bed catalytic methanator and a membrane module for methane upgrading. A top-down approach is first employed to derive optimal system designs step by step from the system concept, to optimal conceptual designs with the trade-off between system efficiency and methane yield, to design-point selection and heat exchanger network design. Then, exergy evaluation with the exergy calculated into thermal – mechanical – non-reactive – reactive parts is applied to the derived four specific system designs to understand how exergy dissipation and performance of the overall system and each component vary from one to another. The results show that the system efficiency can reach between 80 and 85% (HHV) or 75–80% (LHV) when operating SOE with an inlet temperature of 700 °C and a utilization factor over 60%, above which electrical steam generation can be avoided and the steam can be generated by the heat from methanation reaction (around 80–85%) and anode outlet (15–18%). The system's exergy efficiency can achieve around 75–80% with the input exergy mainly destructed within the SOE (25–35%), methanator (25–35%) and heat exchangers (10–17%). However, exergy efficiencies of the SOE and methanator are high, over 90%. Depending on the temperature level of the cold stream and the temperature difference, heat exchangers generally have an exergy efficiency of over 50–80%. The electrical steam generator can only achieve an efficiency of around 20% and leads to a significant drop of system efficiency if employed; however, small electrical heating to reach the desired SOE inlet temperature, although bad, is acceptable. Therefore, one preliminary design guideline for such systems should be the avoidance of electrical steam generation.
Article 0 Reads 0 Citations Biomass logistics and environmental impact modelling for sugar-ethanol production Jairo Alexander Lozano-Moreno, François Maréchal Published: 01 February 2019
Journal of Cleaner Production, doi: 10.1016/j.jclepro.2018.10.310
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Article 0 Reads 0 Citations Multi-objective optimization of sorption enhanced steam biomass gasification with solid oxide fuel cell Thanaphorn Detchusananard, Shivom Sharma, François Maréchal,... Published: 01 February 2019
Energy Conversion and Management, doi: 10.1016/j.enconman.2018.12.047
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Article 0 Reads 0 Citations A Cogeneration System Based on Solid Oxide and Proton Exchange Membrane Fuel Cells With Hybrid Storage for Off-Grid Appl... Francesco Baldi, Ligang Wang, Mar Pérez-Fortes, François Mar... Published: 18 January 2019
Frontiers in Energy Research, doi: 10.3389/fenrg.2018.00139
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Solid oxide fuel cells (SOFC) have developed to a mature technology, able to achieve electrical efficiencies beyond 60%. This makes them particularly suitable for off-grid applications, where SOFCs can supply both electricity and heat at high efficiency. Concerns related to lifetime, particularly when operated dynamically, and the high investment cost are however still the main obstacles toward a widespread adoption of this technology. In this paper, we propose a hybrid cogeneration system that attempts to overcome these limitations, in which the SOFC mainly provides the baseload of the system. Introducing a purification unit allows the production and storage of pure hydrogen from the SOFC anode off-gas. The hydrogen can be stored, and used in a proton exchange membrane fuel cell (PEMFC) during peak demands. The SOFC system is completed with a battery, used during periods of high electricity production. We propose the use of a mixed integer-linear optimization framework for the sizing of the different components of the system, and particularly for identifying the optimal trade-off between round-trip efficiency and investment cost of the battery-based and hydrogen-based storage systems. The proposed system is applied and optimized to two case studies: an off-grid dwelling, and a cruise ship. The results show that, if the SOFC is used as the main energy conversion technology of the system, the use of hydrogen storage in combination with a PEMFC and a battery is more economically convenient compared to the use of the SOFC in stand-alone mode, or of pure battery storage. The results show that the proposed hybrid storage solution makes it possible to reduce the investment cost of the system, while maintaining the use of the SOFC as the main energy source of the system.
Article 0 Reads 0 Citations Interactive Optimization With Parallel Coordinates: Exploring Multidimensional Spaces for Decision Support Sébastien Cajot, Nils Schüler, Markus Peter, Andreas Koch, F... Published: 14 January 2019
Frontiers in ICT, doi: 10.3389/fict.2018.00032
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Interactive optimization methods are particularly suited for letting human decision makers learn about a problem, while a computer learns about their preferences to generate relevant solutions. For interactive optimization methods to be adopted in practice, computational frameworks are required, which can handle and visualize many objectives simultaneously, provide optimal solutions quickly and representatively, all while remaining simple and intuitive to use and understand by practitioners. Addressing these issues, this work introduces SAGESSE (Systematic Analysis, Generation, Exploration, Steering and Synthesis Experience), a decision support methodology, which relies on interactive multiobjective optimization. Its innovative aspects reside in the combination of (i) parallel coordinates as a means to simultaneously explore and steer the underlying alternative generation process, (ii) a Sobol sequence to efficiently sample the points to explore in the objective space, and (iii) on-the-fly application of multiattribute decision analysis, cluster analysis and other data visualization techniques linked to the parallel coordinates. An illustrative example demonstrates the applicability of the methodology to a large, complex urban planning problem.