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Olive mill solid waste gasification in a pilot-scale downdraft gasifier with three-stage air supply: performance, mass-energy balance and fate of inorganic elements

Fuel

Model development for the gasification of olive mill solid waste

HAL (Le Centre pour la Communication Scientifique Directe), Sep 15, 2019

A new continuous fixed bed reactor to study wood char gasification

HAL (Le Centre pour la Communication Scientifique Directe), Oct 17, 2005

Refonctionnalisation de sols en vue de la production d’une biomasse saine à vocation énergétique (projet Biosaine)

HAL (Le Centre pour la Communication Scientifique Directe), Nov 26, 2019

Caractérisation de grignons d’olives en vue d’une valorisation thermochimique par gazéification

Environnement, Ingénierie & Développement, 2019

La biomasse est une source d’énergie renouvelable qui peut contribuer de manière significative à ... more La biomasse est une source d’énergie renouvelable qui peut contribuer de manière significative à la réduction de la consommation de combustibles fossiles. L’utilisation de déchets agricoles ou agro-industriels tels que les grignons d’olives est particulièrement pertinente. La gazéification est une technique prometteuse de valorisation énergétique des déchets pour ce type de résidus lignocellulosiques. La technologie est cependant adaptée à un panel relativement limité de combustibles solides ayant des spécifications définies, qui doivent donc être caractérisées correctement. Le but de cette étude était d’analyser et de comparer des grignons d’olives de 3 origines différentes par des techniques complémentaires telles que la spectroscopie infrarouge à transformer de Fourier, la thermogravimétrie couplée à l’analyse calorimétrique différentielle et la pyrolyse suivie d’une chromatographie en phase gazeuse / spectrométrie de masse (Py-CG/SM). Les résultats soulignent la nature complexe ...

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Comparative analyses of three olive mill solid residues from different countries and processes for energy recovery by gasification

Renewable Energy, 2019

Biomass is a renewable energy source which may provide a significant contribution to the reductio... more Biomass is a renewable energy source which may provide a significant contribution to the reduction of fossil fuels consumption and the associated environmental impacts. The use of agricultural or agro-industrial waste such as solid residues from olive oil production is particularly relevant since it may combine several benefits. Gasification is a promising waste-to-energy technique for this type of lignocellulosic residues. The technology however is adapted to a relatively limited panel of solid waste fuels of defined specifications, which must therefore be characterized properly to assess their adaptation. The purpose of this research was to analyze and compare three different olive mill solid residues by complementary techniques such as Fourier transform infrared spectroscopy (FTIR) and thermochemical methods, in order to characterize these residues as potential fuels for gasification. The results obtained underlined the complex nature of the residues and indicated that they were mainly organic, with very little mineral matter. In addition to the major organic components (cellulose, hemicelluloses and lignin), the presence of several minor organic constituents was shown by thermogravimetry coupled to differential scanning calorimetry and FTIR. The gas produced from pyrolysis was analyzed by gas chromatography and mass spectrometry. It was found to contain several degradation products from lignocellulosic material and olive oil, such as hydroxyacetone, furfural and methoxyphenols. The influence of the olive oil extraction process (two-phase or threephase) was also demonstrated. It was shown that the thermochemical degradation of olive mill residues followed a complex pathway but the composition of the residues met the requirements for gasification for most parameters.

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Valorisation des coques d’anacarde par pyrolyse au Bénin

Environnement, Ingénierie & Développement, 2015

Faced to difficulties to energy access and management of waste from the processing of cashew nuts... more Faced to difficulties to energy access and management of waste from the processing of cashew nuts in Benin, the shells stored in cashew nuts processing plants are directly used as fuel. They are therefore burned in kilns to provide the energy required to produce the heat for embrittlement of nuts, steaming and drying almonds. This non controlled combustion generates significant pollution because CNSL, substance contained in the shells, produces abundant and acrid smoke irritating to eyes. To overcome this problem, we have constructed in Benin two pyrolysis plants on the basis of a reactor designed by CEFREPADE and RON-GEAD. Those reactors have been used in Benin for energy recovery from cashew nut shells. This experiment of promotion of cashew nuts showed that the pyrolysis reactor used can be able to produce gaseous energy of approximately 82% of the hull mass processed and produces about 18% of charcoal. Furthermore, on the energy point of view, the recovered gas corresponds to 74...

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Caractérisation et traitement thermochimique des coques d’anacarde en vue de leur valorisation énergétique dans les procédés de transformation artisanale de noix de cajou

Environnement, Ingénierie & Développement, 2012

The use of wood and natural gas to cover the energy needs in transformation process of cashew nut... more The use of wood and natural gas to cover the energy needs in transformation process of cashew nuts has a negative impact on the environment protection. Ligneous shells stemming from nuts shelling are soaked with CNSL and require an intermediate treatment before their energy valuation.The small scale transformation units of Burkina Faso face this problem of deficit of technical solutions efficiently applicable in their context. The objective of this study thus aims at characterizing cashew shells and at proposing possible ways of valuation. After an initial characterization of shells, thermochemical comparative study was realized in conditions of torrefaction (250°C) and of pyrolysis (450°C). The results of the realized tests show that the thermochemical treatment allows to obtain three types of products: solid (char), liquid (oil or condensable fraction of gases) and gaseous (incondensable gas), in proportions and quality relatively different proportions and quality according to the...

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A new experimental Continuous Fixed Bed Reactor to characterise wood char gasification

Fuel, 2010

Two-stage fixed bed gasification is one of the most promising technologies for low and medium ene... more Two-stage fixed bed gasification is one of the most promising technologies for low and medium energy production from biomass. In industrial processes, control and optimisation is often based on constructor know-how rather than on an understanding of the mechanisms involved. We present a new original tool, the Continuous Fixed Bed Reactor (CFiBR), which was specifically designed and built to enable a fine understanding of the limiting stage of a gasifier: the char bed gasification zone. The reactor, the instrumentation, the operating procedure and setup tests are described in detail. The potential of the reactor is demonstrated through the characterisation of the gasification of a continuous wood char bed. Temperature profiles and gas concentrations along the 65 cm bed were established and showed that the most reactive zone was the first 10 cm of the char bed. Accurate energy and mass balances provided relevant information regarding the contributions of the main reactions involved in the fixed char bed gasification process.

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Gasification of Wood Char in Single and Mixed Atmospheres of H2O and CO2

Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2013

In gasification processes, char-H 2 O and char-CO 2 are the main heterogenous reactions that are ... more In gasification processes, char-H 2 O and char-CO 2 are the main heterogenous reactions that are responsible for carbon conversion into H 2 and CO. These two reactions are generally looked at independently without considering interactions between them. The objective of this work was to compare kinetics of each reaction alone to kinetics of each reaction in a mixed atmosphere of H 2 O and CO 2. A char particle was gasified in a macro thermo gravimetry reactor at 900 ı C successively in H 2 O/N 2 , CO 2 /N 2 , and H 2 O/CO 2 /N 2 atmospheres.

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Gasification of woodchip particles: Experimental and numerical study of char–H2O, char–CO2, and char–O2 reactions

Chemical Engineering Science, 2011

In wood gasification, oxidation of char particles by H 2 O, CO 2 or O 2 plays a major role in the... more In wood gasification, oxidation of char particles by H 2 O, CO 2 or O 2 plays a major role in the performance and efficiency of air gasifiers. These reactions are generally analyzed under carefully design and controlled laboratory conditions, using either micro-samples to focus on the reaction kinetics or large spherical particles, but rarely using the real shape encountered in industrial processes. The objective of this work was to conduct a complete parametric study on char gasification kinetics at particle scale in operating conditions like those of industrial applications. Experimental results from a macro-Thermo Gravimetric reactor are compared to those from a char particle model, which analyzes reactivity versus conversion through the surface function F(X). We first show that particle thickness is a representative dimension of a char particle with respect to its apparent kinetics. Second, considering the three reactions independently, we compared the influence of temperature (800-1050 1C) and reacting gas partial pressure (0.03-0.4 atm) and determined the intrinsic kinetic parameters and surface function F(X). Simulations provided profiles of temperature and gas concentrations within the particle, mainly revealing internal mass diffusion limitation. The experimental data base proposed and the model results improve our understanding of the gasification reaction and support the elaboration of process models.

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Gazéification du charbon de plaquettes forestières : particule isolée et lit fixe continu

La gazeification de la biomasse se positionne aujourd'hui comme une filiere pertinente pour l... more La gazeification de la biomasse se positionne aujourd'hui comme une filiere pertinente pour la production d'energie de type electricite, gaz naturel de synthese ou encore biocarburants. Les mecanismes mis en jeu dans ce procede restent aujourd'hui encore mal connus. Dans les procedes a lit etage, la zone de gazeification du residu carbone conditionne significativement les rendements energetiques et la qualite des gaz produits. Cette these vise a ameliorer la comprehension de cette zone reactionnelle afin d'optimiser la conception et le fonctionnement de ces reacteurs. La gazeification d'un charbon de plaquettes forestieres a ete caracterisee a l'echelle de la particule isolee, puis a l'echelle du lit fixe continu. Nous avons mesure les vitesses de gazeification de particules de differentes tailles et sous plusieurs atmospheres, au moyen d'un reacteur de type "macro-ATG". Entre 800 et 1000°C, l'epaisseur de la particule est la dimension c...