Fioul

Résumé

thumb|Un réservoir de fioul en Australie. Le fioul ou mazout est un combustible dérivé du pétrole, utilisé notamment dans les chaudières. Il est classé dans les ressources énergétiques fossiles. Il présente des rendements élevés mais, compte tenu de sa très large utilisation pour la production d'énergie thermique (pour le chauffage en chaudière) et mécanique (moteurs dits thermiques), il contribue notablement à la pollution de l'air par l'émission de particules fines cancérigènes et au réchauffement climatique par l'émission de . Terminologie Le nom masculin « fioul », surtout utilisé en France et recommandé par la délégation générale à la langue française et aux langues de France (DGLFLF), est issu de la francisation du mot anglais fuel, lequel désigne tout combustible (bois, bois énergie, charbon, etc.) ou carburant. Le mot anglais fuel provient sans doute du franco-normand fouaille (ce qui alimente le feu, ou bien, l'action de frapper/fouetter), et a peut-être une loint

Source officielle

https://fr.wikipedia.org/wiki/Fioul

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alt=Flasque comprenant du pétrole brut|vignette|Pétrole brut Le pétrole (en latin , du grec petra, « roche », et du latin , « huile »), dit aussi naphte dans l'Antiquité, est une huile minérale d’or

thumb|Le combustible consommé dans une cheminée traditionnelle est généralement du bois. Un combustible est un composé chimique qui, avec un comburant (comme le dioxygène) et de l'énergie, se consume

Le gazole, gasoil, gas-oil, diesel (par antonomase), ou encore diésel (orthographe rectifiée de 1990), est un carburant pour moteur à allumage par compression (moteur Diesel). Physiquement, c'est un

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Optimal Integration of Renewable Energy in Buildings Using Predictive Control

Tomasz Kaminski

Today’s world faces a large problem which is global warming. Glaciers melting see, and oceans water level rising, and droughts in Africa. According to [1] there are seven main sources of CO2 emissions from fossil fuels combustion: 1. Solid fuels (e.g. coal) – 35% of CO2 emission 2. Liquid fuels (e.g. gasoline, fuel oil) – 36% of CO2 emission 3. Gaseous fuels (e.g. natural gas) – 20% of CO2 emission 4. Flaring gas industrially and at wells:

2009

Chargement

With the unsustainable use of fossil fuels increasing strains on human institutions and ecosystems, the development of a renewable energy alternative is of paramount importance. Second generation biorefineries, based on the production of fuels and chemicals from lignocellulosic biomass, appear as attractive alternative to their non-renewable counterparts. Within the multiplicity of existing valorisation routes, enzymatic hydrolysis of lignocellulosic biomass into its constituent sugars has generated considerable interest, notably in the context of biofuels production. However, major hurdles stemming from the intricate structure of the lignocellulosic feedstocks still impede large-scale deployment of this process. The multiplicity of highly intertwined spatiotemporal factors impacting the enzymatic hydrolysis of lignocellulosic biomass represents a challenge to rationally design efficient hydrolysis process. Here, we propose a theory-based modelling framework relying on pore-diffusion and surface reaction to explore the effects of recognised bottlenecks on the enzymatic hydrolysis of lignocellulosic substrates. The model is based on a set of partial differential equations describing the evolution of the substrate morphology to investigate the interplay between experimental conditions and the physical characteristics of biomass particles as the reaction proceeds. The overall quantity of cellulase present in the hydrolysis mixture is carefully considered to investigate its interplay with the available accessible cellulose surface. Also, non-uniformity in terms of cellulose accessibility and cellulose digestibility are introduced in the model to weight their influence on observed hydrolysis rates. Finally, deactivation mechanisms are considered through unproductive adsorption of cellulases on both cellulose and lignin fractions, with the existence of such phenomena alleged to be critical in the efficiency of the hydrolysis process. Based on predictions of our model, we were able to confirm the critical role of cellulose accessibility, as defined by the combination of particle size, porosity and accessible cellulose surface, in dictating early reaction rates for a range of pretreated beech wood substrates. While high biomass loading should be favoured to improve enzyme penetration in the substrates, high enzyme loadings going beyond the initial number of cellulose adsorption appeared beneficial in notably two cases: (i) to promote internal diffusion in large particles and (ii) counteract undesired enzyme adsorption on lignin. For the latter, a relatively low increase in enzyme loading was sufficient to offset the resulting slowdown. We also showed that the existence of structural heterogeneities, and in particular non-uniform pore volume distribution within the lignocellulosic samples, contribute to the rate slowdown observed at later stage of the hydrolysis, while not explaining it in its entirety. Unproductive adsorption to cellulose, coupled to decrease in the cellulase efficiency at the cellulose surface, appeared as major contributor to the rate slowdown. Overall, we show how the use of a theory-based model can help decouple and evaluate the effects of key factors in the enzymatic hydrolysis of lignocellulosic biomass. As such, our model can help pave the way towards efficient integrated rational design strategies for enzyme process engineering for biomass conversion.

EPFL2021

Chargement

Immobilization of rapeseed press-cake in an alginate matrix for the sorption of atrazine

Julien Boucher, Véronique Breguet, Ian William Marison, Urs von Stockar

Due to residual oil retained within it, rapeseed press-cake has been shown to be effective for the removal of atrazine from water through an absorption mechanism. However, it is difficult to put this into practice due to the hygroscopic nature of the press-cake resulting in considerable swelling, together with the formation of a thick paste which hinders phase separation. In order to overcome this, press-cake has been immobilized in an alginate matrix. The kinetics and sorption efficiency of this immobilized press-cake to absorb the model pesticide atrazine, has been studied. The results show that the rate of atrazine removal is slower than for free press-cake, although the total amount of atrazine removed is the same (K-pc/w = 0.25). Phase separation was greatly simplified. The alginate immobilized press-cake could be dried, in order to reduce volume and weight, with no adverse effect on atrazine removal kinetics or sorption properties. (c) 2007 Elsevier Ltd. All rights reserved.

2008

Chargement

EPFL2021