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Solid Residues (Biochar, Bottom Ash, Fly Ash, …)
No full textInternational audienceSolid co-products from biochemical, chemical and thermochemical processes of biomass and biowaste have gained momentum in utilization as secondary raw materials. These solids are carbon-based or mineral-based materials, and for their suitable use in a number of fields, various properties should be determined. This chapter addresses advanced techniques used to determine physical and chemical properties of these solid residues. For each technique, the basics and protocols are described. Post-treatment procedures and interpretation of the results obtained are also provided for some residues
Municipal Solid Waste
No full textInternational audienceIn this chapter, the sampling, preconditioning, as well as physico-chemical, biochemical and thermal characterization methods for municipal solid waste are introduced. The typical equipment used in the sample preparation and characterization are illustrated. Furthermore, an overview of the characteristics of municipal solid waste is presented which provides a useful starting database
Hydrogen spillover in the Fischer‐Tropsch synthesis on carbon‐supported cobalt catalysts
No full textInternational audienceThe Fischer‐Tropsch reaction transforms syngas into high added value products, among which liquid fuels. Numerous parameters determine catalytic activity and selectivity towards the most desired hydrocarbons. The performances of cobalt‐based catalysts used in the reaction are known to depend critically on Co particle size and crystallographic phase. Here, we present a comparative study of Co‐based catalysts supported on three carbon supports: multi‐wall carbon nanotubes, carbon nanofibers and a fibrous material. Our results show that, while the selectivity towards C5+ follows the expected tendency with respect to Co particle size, this is not the case for the TOF. These results can be rationalized considering that the amount of H 2 uptake on each catalyst increases with oxygen and defect concentration on the support. The catalyst, on the support presenting many edges and oxygen surface groups, necessary for H 2 spillover, presents the highest activity. Furthermore, the hydrogen spillover contributes to the enhancement of olefin hydrogenation and methane production
The Distinctive Effects of Glucose-Derived Carbon on the Performance of Ni-Based Catalysts in Methane Dry Reforming
No full textInternational audienceThis study aimed to investigate the effect of carbon derived from glucose (C) on the physicochemical characteristics and catalytic activity of Ni, supported over SiO2, ZSM-5, and TiO2 in methane dry reforming. Among the Ni catalysts without C, Ni/SiO2 exhibited the highest CH4-CO2 conversion and stability at all experimented temperatures. On the other hand, the C-incorporated catalysts prepared by glucose impregnation, followed by pyrolysis, showed dissimilar performances. C improved the stability of Ni/SiO2 in the reforming at 650 °C and 750 °C and increased the CH4 and CO2 conversion to the level close to the thermodynamic equilibrium at 850 °C. However, this element did not substantially affect the activity of Ni/ZSM-5 and exerted a retarding effect on Ni/TiO2. Characterizations with H2-TPD, XRD, EXAFS, and STEM-EDS revealed that the different influences of C by the supports were attributed to the extent of metal dispersion and metal-support interaction
Supporting group decision makers to locate temporary relief distribution centres after sudden-onset disasters: A case study of the 2015 Nepal earthquake
No full textInternational audienceIn the humanitarian response, multiple decision-makers (DMs) need to collaborate in various problems, such as locating temporary relief distribution centres (RDCs). Several studies have argued that maximising demand coverage, reducing logistics costs and minimising response time are among the critical objectives when locating RDCs after a sudden-onset disaster. However, these objectives are often conflicting and the trade-offs can considerably complicate the situation for finding a consensus.To address the challenge and support the DMs, we suggest investigating the stability of non-dominated alternatives derived from a multi-objective model based on Monte Carlo Simulations. Our approach supports determining what trade-offs actually matter to facilitate discussions in the presence of multiple stakeholders. To validate our proposal, we extend a location-allocation model and apply our approach to an actual data-set from the 2015 Nepal earthquake response. Our analyses show that with the relative importance of covering demands, the trade-offs between logistics costs and response time affects the numbers and locations of RDCs considerably. We show through a small experiment that the outputs of our approach can effectively support group decision-making to develop relief plans in disasters response
Prediction of Oil Yield from Oil Palm Mesocarp Using Thermally Assisted Mechanical Dewatering (TAMD)
No full textInternational audienceThermally assisted mechanical dewatering (TAMD) is a new technology for the separation of solid/liquid. When applied to “nature-wet” biomass, the TAMD process significantly enhances the separation yield. In the present study, TAMD was used to extract the crude palm oil (CPO) from mesocarp. The CPO yield of 70.77 wt% was achieved at optimum parameters of 73.0 °C, 6.7 bar and 60 min of extraction time. This CPO yield was comparable with previous works on the enzymatic extraction and hot compressed water extraction (HCWE) with CPO yield of 71.0 and 70.50 wt% respectively. Apart from that, this value was higher for about 13.80% compared to commercial CPO extracted using screw press which obtained the oil yield of 61.0 wt%. Based on the literatures, the highest CPO yield was obtained from supercritical CO2 extraction at 77.0 wt% whereas the lowest CPO yield was extracted using subcritical R134a which gave 66.0 wt% of oil yield. Nevertheless, the operational conditions of supercritical CO2 were 300 bar and 80 °C which were higher than that of TAMD. In conclusion, TAMD extraction has a potential to be an alternative method to extract CPO by producing higher oil yield
Microstructural characterization of IN625 - NiCrAlY bond coat system fabricated by additive manufacturing
No full textInternational audienceThis research is conducted on the IN625 superalloy as a substrate fabricated by selective laser melting method, which is coated with bond coat. The microstructure and chemical composition are investigated using optical microscopy and Field Emission Scanning Electron Microscopy (FE-SEM) coupled to an Energy Dispersive Spectroscopy (EDS) detector. The bond coat and substrate present a homogeneous microstructure, strong metallurgical bond and good adherence between substrate and bond coat. Moreover, the microstructure is difficult to distinguish between the bond coat and substrate using optical microscopy. Furthermore, the selective laser melting has a low level of Oxygen, indicating a low diffusion and oxidation rate during manufacturing process
Introduction to a Physics-Based Theory to Manage Risks and Opportunities in Supply Chains
No full textInternational audienceCurrently, the management of risks and opportunities is highly depending on the ability of managers: to analyze complex situations (with a lack of common vision and decision on the whole supply network), to mobilize their experience and their knowledge. The goal of this article is to introduce a new vision for collaborative network management, especially dedicated to supply chain management. It deals with an innovative and original approach for supply chain management, based on physical principles. With that theory, risks and opportunities can be seen as forces pushing and pulling a system according to its key performance indicators (KPIs)
Simultaneous Control of Two Robotics Arms Sharing Workspace via Visual Predictive Control
No full textInternational audienceThis work addresses the problem of simultaneously controlling two robotic arms to automatically pick up fruits in an orchard. When considering such a scenario, the design of the controller has to face several challenges: (i) the arms share the same workspace, (ii) the presence of obstacles such as branches and other fruits, and (iii) the system evolves in a dynamic environment, i.e., the positions of the fruits and branches change over time. In this paper, it is proposed to control the two robotic arms relying on a Visual Predictive Control (VPC) scheme. It allows to control the system in a reactive fashion while taking into account a large number of constraints. The global and local models of the VPC scheme as well as constraints dealing with collisions or joint boundaries are presented. Finally, the efficiency of the proposed approach is highlighted with numerous simulation results using the PR2 arms model
Fuel flexibility of a pilot plant gasifier using torrefied pellets as feedstock
No full textInternational audienceThe aim of this study is to investigate the possibility of enhancing the gasification process using a pretreated biomass that presents higher heating value, higher C/O ratio and less moisture content than untreated biomass. The aim is to assess the gasification parameters that can be modified in order to achieve the best performance of the gasification system. These research studies have been carried out in collaboration with the Centre RAPSODEE (UMR CNRS 5302, IMT Ecole de mines Albi-Carmaux, France) and the Free University of Bolzano (Italy). The torrefaction of standard pellets is realized using a lab scale rotary kiln unit at RAPSODEE. On the contrary, the gasification tests are carried out at the Free University of Bozen-Bolzano by means of a fixed bed open top gasifier. The tests of pellets torrefaction has been carried out at 250°C and 270°C with two repetitions in order to obtain about 60 kg of pellets for each torrefied condition. The used feedstock is a standard French pellets produced from sawdust of oak and beech following the standard EN 14961-2 (“Wood pellets for non-industrial use”). The pellets are characterized before and after the torrefaction pre-treatment. The gasifier used for the gasification tests is an open top pilot-scale gasifier placed at the Bioenergy and Biofuel Lab of the Free University of Bolzano. The plant is an open top downdraft system, where both gas and feedstock move downward as the reactions proceed. The main difference between un-treated and torrefied pellets is the moisture content. In addition, a slight increase in terms of carbon content and LHV and a slight decrease in terms of volatile matter are observed by moving from standard to torrefied pellets. The torrefied pellets seem to reach lower performances in terms of cold gas efficiency (CGE) and char yield with respect to the standard pellets. However, the trends in terms of ER and CGE suggest that moving toward higher values of ER, higher values of CGE could be reached independently of the material used