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Predicting the transport properties of acid gases in Aqueous MEA solutions using molecular simulation
No full textInternational audienc
An innovative approach for ongoing assessment of critical infrastructures’ resilience based on a nonfunctional requirement ecosystem
No full textInternational audienceGeopolitical context or climate change induced more and more disasters in the two last decades. Particularly, Critical Infrastructures (CI - e.g., water distribution, health care) that support the daily life of societies are impacted by these disasters. These CI are indeed essential. By their various interactions and links, they become more fragile when facing complex situations. For instance, a local event, occurring in a CI (e.g., an accident), can propagate throughout these interactions, impacting other CI, leading to a higher intensity and to a global impact. Classical risks analysis is limited in terms of global and dynamic vision of these CI, to manage these events efficiently and to recover to an acceptable functioning state for the end users. To this purpose, resilience is a useful concept, highlighted by numerous research works and organizations to characterize the best way a CI has to react to an undesirable event and avoid, if possible, its propagation. The purpose of this paper is to present the main principles of a methodology to assess and analyze resilience of a CI based on a multi views and systemic model formalized as a digital twin. This work is done in the frame of the project RESIIST supported by the French research agency ANR (Résilience des infrastructures et systèmes interconnectés, 18-CE39-0018-05) to provide scenarios to test and evaluate the proposed methodology
Effets de taille et de nature des charges sur les propriétés thermiques et mécaniques des composites à matrice PEEK
No full textInternational audienceLes rôles de la taille et de la nature des charges dans les composites sont mis en évidence en comparant quatre types de charges : carbure de silicium, alumine, nitrure de bore et graphite. Leur nature chimique semble être prépondérante sur la taille car elle gouverne les interactions interfaciales charge/matrice qui se traduisent par de meilleures propriétés mécaniques
Hydrochar derived from municipal sludge through hydrothermal processing: A critical review on its formation, characterization, and valorization: Review
No full textInternational audienceAdditional options for the sustainable treatment of municipal sludge are required due to the significant amounts of sludge, high levels of nutrients (e.g., C, N, and P), and trace constituents it contains. Hydrothermal processing of municipal sludge has recently been recognized as a promising technology to efficiently reduce waste volume, recover bioenergy, destroy organic contaminants, and eliminate pathogens. However, a considerable amount of solid residue, called hydrochar, could remain after hydrothermal treatment. This hydrochar can contain abundant amounts of energy (with a higher heating value up to 24 MJ/kg, dry basis), nutrients, and trace elements, as well as surface functional groups. The valorization of sludge-derived hydrochar can facilitate the development and application of hydrothermal technologies. This review summarizes the formation pathways from municipal sludge to hydrochar, specifically, the impact of hydrothermal conditions on reaction mechanisms and product distribution. Moreover, this study comprehensively encapsulates the described characteristics of hydrochar produced under a wide range of conditions: Yield, energy density, physicochemical properties, elemental distribution, contaminants of concern, surface functionality, and morphology. More importantly, this review compares and evaluates the current state of applications of hydrochar: Energy production, agricultural application, adsorption, heterogeneous catalysis, and nutrient recovery. Ultimately, along with the identified challenges and prospects of valorization approaches for sludge-derived hydrochar, conceptual designs of sustainable municipal sludge management are proposed
Phosphorus recovery from municipal sludge-derived ash and hydrochar through wet-chemical technology: A review towards sustainable waste management: Review
No full textInternational audiencePhosphorus (P) is a non-renewable resource, and its recovery and recycling are necessary for meeting future P demands and environmental conservation. Ash and hydrochar from incineration and hydrothermal liquefaction (HTL) of municipal sludge, respectively, represent promising sources for efficient P recovery. The full-scale application of wet-chemical techniques has proven their technical feasibility for P recovery from sludge-derived ash. HTL for sludge treatment has received significant attention for producing biocrude with net-positive energy recovery. P recovery from the solid by-product of sludge HTL, hydrochar, is a critical step in holistic sustainable sludge management. This review aims to guide P recovery from sludge-derived ash and hydrochar by presenting recent advances in wet-chemical extraction and precipitation. By comparing their characteristics, ash and hydrochar derived from municipal sludge exhibit similar feasibilities and challenges for P recovery. Extraction is recognized as the critical step for P recovery. The advantages and disadvantages of various P extraction approaches are provided. Acidic extraction achieves high efficiency (up to 100%) but requires removal of co-extracted heavy metals. Alkaline extraction prevents metals contamination but shows low efficiency (<70%). Sequential extraction is first identified as an important advance in this review, with promising P extraction efficiencies (70–91%) and low metal interferences. Three possible fertilizers (struvite, calcium phosphates, and vivianite) are recommended through the final precipitation, given their pros and cons of recovery. Ultimately, this review highlights the need for a wastewater biorefinery integrating wastewater treatment, HTL (energy recovery), and nutrient recovery for sustainable sludge management
Beyond confinement effects in Fischer-Tropsch Co/CNT catalysts
No full textInternational audienceFischer-Tropsch catalyst preparation parameters, such as cobalt precursor and impregnation solvent, determine structure and in fine catalytic performances of Co-based catalysts. Co particles of 3-7 nm mean size were prepared by incipient wetness impregnation on surface-oxidized CNT. In this work the crucial impact of the chemistry operating between the Co precursor and the support during catalyst preparation on the catalyst properties is demonstrated and the influence of CNT surface chemistry on catalyst characteristics has been assessed. Very good correlations were found between: i) the reduction degree of the catalysts and the concentration of the Co(OOC-) surface species; ii) the Cohcp/Cofcc ratio and the amount of CO-releasing groups on the support surface; iii) the extent of hydrogen spillover and the concentration of quinone surface groups. The initial catalytic activity could only be correlated to a combination of catalyst features: percentage of Cohcp, Co confinement, hydrogen spillover, and surprisingly the inverse of the Co initial particle size. No significant differences in SC5+ selectivity were observed, in accordance with comparable final Co particle size. Finally, the stability of the catalyst can be correlated with the initial Co particle size and the percentage of Cohcp in the catalyst. These results confirm the significant impact of the precursor/support couple on the structure and performance of Co/CNT catalysts, and reveal for the first time an inverse correlation between Co particle size and activity, which is attributed to the confined Cohcp phase
Review of the utilization of waste biomaterial resources of selected food crops: rice, cassava, cocoa, sorghum and oil palm
No full textThe Federal Ministry of Agriculture and Rural Development (Nigeria) in its Minna 2011 Staff Retreat, unveiled an Agricultural Transformational Agenda in which rice, cassava, cocoa, oil palm, and sorghum were identified as target commodity value chain with which to drive the nation’s economy. One of the transformational policies in view of this development is thefinancing of value chains for the processing of these target crops. However, alongthe value chain, Rice husks, Cassava peels, Cocoa pods, Oil Palm Empty Fruit Bunches (EFB), and Sorghum bagasse, each in millions of metric tons per annum are either inefficiently used, underutilized, or totally wasted. In this paper therefore, the authorpresents a review of simple processing techniques to convert these biomaterials (wastes) into value added products (materials) and sustainable energy sources. Furthermore, the economic cost and environmental benefits of the effective biomaterial utilization of these waste resources is drawn-out
Assessing Physical Internet potential for Humanitarian Supply Chains
No full textInternational audienceNowadays, Humanitarian Supply Chain stakes are changing drastically, implying a need for new methods and tools. One of the most promising evolution is definitively "Physical Internet". The current research work investigates how to assess the potential benefits and limits of using the Physical Internet paradigm within Humanitarian Supply Chains. Practically, the proposal provides (i) a systems engineering-oriented framework and (ii) a set of specific modeling features. This contribution will allow assessing efficiently and accurately, impacts of Physical Internet in Humanitarian context. Finally, the paper develops avenues for further research based on the proposal
3E analysis of a biomass-to-liquids production system based on solar gasification
No full textInternational audienceThe solar gasification system (SGS) and traditional system are modeled by Aspen Plus. And their energetic, economic as well as ecologic (3E) performance are compared. The effects of different feedstocks and Direct Normal Irradiance (DNI) to the productivity and efficiency of SGS are also carried out. The results show that a biomass-based, solar-assisted liquid fuel production system offers a productivity increasing potential of 49.44% more refined syngas and 65.74% more liquid fuels due to its higher utilization of feedstock. And for the same reason, the energetic performance of SGS increases from 40.22% to 40.66% for thermal efficiency and from 38.35% to 41.35% for exergy efficiency compared with those of reference system. The final price of products in SGS could only be equal to that of reference system when the carbon tax is under considering, while both of them shows no superiority to that of petroleum products. SGS has a better ecology performance contributed by less total carbon and water footprints which are only 55.27% and 61.34% of those of the reference system