Author: Sofien Cavagnol
Publisher:
ISBN:
Category :
Languages : fr
Pages : 197
Get Book Here
Book Description
La torréfaction est une étape nécessaire pour la production de gazoles à partir de biomasse lignocellulosique par voie thermochimique (chaîne Biomass To Liquid). Il s'agit d'un traitement thermique dans le domaine de température compris entre 200 et 300°C en milieu non oxydant ; le but de cette étape est de modifier la structure de la biomasse afin d'en faciliter le transport pneumatique après broyage. Cependant, des réactions exothermiques ont été observées et peuvent mener à un mauvais contrôle de la température au sein du réacteur et nuire à la qualité des produits, voire endommager l'installation. L'objectif de cette thèse est de quantifier la chaleur émise par les réactions exothermiques de torréfaction de la biomasse lignocellulosique, et d'en étudier les impactes lors du changement d'échelle, où les phénomènes de transfert de masse et de chaleur ne sont plus négligeables. Durant nos travaux, des mesures de perte de masse et de flux de chaleur ont été réalisées à l'échelle de la poudre (microparticule) sur trois types d'essence de bois (robinier, épicéa et eucalyptus) ainsi que sur les principaux constituants de la matière lignocellulosique (cellulose, xylane, glucomannane et lignine). Un modèle cinétique capable de reproduire la perte de masse ainsi que le flux de chaleur généré par les réactions exothermiques, a été développé. Il utilise le concept de distribution d'énergie d'activation. Tous les paramètres du modèle ont été identifiés par méthode inverse sur un ensemble de tests isothermes d'une durée de 10 heures. Cela permet de proposer des paramètres cinétiques robustes et des valeurs fiables d'énergie d'activation. Par la suite, des mesures de température pendant des essais de torréfaction sur des planches de bois (méso-échelle) et sur un lit fixe de particules (échelle macroscopique) ont permis de mesurer la propagation d'une onde thermique générée par les réactions exothermiques. Une modélisation macroscopique qui intègre le modèle cinétique développé permet de propager l'effet des réactions exothermiques à l'échelle de la macro particule. L'analyse de l'ensemble des résultats permet de mettre en exergue l'importance de l'échelle lit sur l'emballement thermique observé expérimentalement. L'ensemble du travail, mené à différentes échelles spatiales et complété par une analyse permettant de relier ces échelles entre-elles, constitue une avancée significative vers la prédiction de l'exothermicité de la torréfaction afin d'assurer la sécurité et la faisabilité à l'échelle industrielle.
Author: Cécile Casajus
Publisher:
ISBN:
Category :
Languages : fr
Pages : 208
Get Book Here
Book Description
La torréfaction est une opération de pyrolyse lente sur l’intervalle de température 220-280°C en milieu inerte. Cette technique appliquée aux résidus ligno-cellulosiques modifie leurs propriétés thermiques et les rend stables, broyables et exempts d’humidité. Ils peuvent alors être considérés comme une matière première intéressante pour les procédés de combustion et de gazéification. Avant le développement de cette technologie à l’échelle industrielle, il est nécessaire d’enrichir notre niveau de connaissance associé au procédé de torréfaction et de compléter les données existantes par des données propres aux échantillons étudiés dans le cadre de ce travail. Pour ce faire, plusieurs études expérimentales ont été menées afin d’identifier les paramètres opératoires clés de la torréfaction et de comprendre les mécanismes mis en jeux lors de ce traitement thermique. Parallèlement, un modèle numérique d’un réacteur de torréfaction de type lit fixe à contre courant a été développé. Ce modèle, basé sur une approche monodimensionnelle permet une meilleure compréhension des phénomènes se déroulant dans ce type d’installation. Il a également permis une aide au dimensionnement du pilote expérimental d’une capacité de deux kilogrammes par heure développé dans le cadre de cette thèse et du programme PREBIOM.
Author: Linda Strande
Publisher: IWA Publishing
ISBN: 1780404735
Category : Technology & Engineering
Languages : en
Pages : 428
Get Book Here
Book Description
It is estimated that literally billions of residents in urban and peri-urban areas of Africa, Asia, and Latin America are served by onsite sanitation systems (e.g. various types of latrines and septic tanks). Until recently, the management of faecal sludge from these onsite systems has been grossly neglected, partially as a result of them being considered temporary solutions until sewer-based systems could be implemented. However, the perception of onsite or decentralized sanitation technologies for urban areas is gradually changing, and is increasingly being considered as long-term, sustainable options in urban areas, especially in low- and middle-income countries that lack sewer infrastructures. This is the first book dedicated to faecal sludge management. It compiles the current state of knowledge of the rapidly evolving field of faecal sludge management, and presents an integrated approach that includes technology, management, and planning based on Sandecs 20 years of experience in the field. Faecal Sludge Management: Systems Approach for Implementation and Operation addresses the organization of the entire faecal sludge management service chain, from the collection and transport of sludge, and the current state of knowledge of treatment options, to the final end use or disposal of treated sludge. The book also presents important factors to consider when evaluating and upscaling new treatment technology options. The book is designed for undergraduate and graduate students, and engineers and practitioners in the field who have some basic knowledge of environmental and/or wastewater engineering.
Author: Lew Christopher
Publisher: Royal Society of Chemistry
ISBN: 1849735069
Category : Technology & Engineering
Languages : en
Pages : 323
Get Book Here
Book Description
This reference book describes how bioprocessing and biotechnology could enhance the value extracted from wood-based lignocellulosic fiber by employing both biochemical and thermochemical conversion processes. It documents recent accomplishments and suggests future prospects for research and development of integrated forest biorefineries (IFBR) as the path forward for the pulp, paper and other fiber-processing industries. This is the only book to cover this area of high economic, social, and environmental importance. It is aimed at industrialists and academics from diverse science and engineering backgrounds including chemical and biotechnology companies, governmental and professional bodies, and scholarly societies. The Editor and contributors are internationally recognized scientists and many are leaders in their respective fields. The book starts with an introductory overview of the current state of biorefining and a justification for future developments. The next four chapters deal with social, economic and environmental issues related to regulations, biomass production and supply, process modelling, and life cycle analysis. Subsequent chapters focus on the extraction of biochemicals from biomass and their potential utilization to add value to the IFBR prior to pulping. The book then presents, compares and evaluates two types of forest biorefineries based on kraft and organosolv pulping. Finally, the book assess the potential of waste biomass and streams, such paper mill sludge and black liquor, to serve as feedstock for biofuel production and value-added biomaterials through both the biochemical and thermochemical routes of biomass bioprocessing. The economics of the described IFBR processes and products, and their environmental impact, is a major focus in most of the chapters. Practical examples are presented where relevant and applicable.
Author: David M. Robbins
Publisher: IWA Publishing
ISBN: 178040476X
Category : Science
Languages : en
Pages : 148
Get Book Here
Book Description
This is a practical handbook providing a step-by-step approach to the techniques used for characterizing wastewater sources and investigating sites where collection, treatment and reuse/disposal technologies will be installed. It is intended to help enable local implementation of on-site and decentralized wastewater management system (DWMS)for wide scale use in development settings. How to Design Wastewater Systems for Local Conditions in Developing Countries helps local service providers and regulatory officials make informed decisions through the use of tools, checklists and case studies. It includes a link to a web based community of on-site and decentralized wastewater professionals, which contains related tools and case studies. This handbook serves as a reference for training classes, certification programs, and higher education programs in civil and sanitary engineering. There is an increasing interest on the part of local government officials and private sector service providers to implement wastewater treatment systems to solve sanitation problems. The model presented in this handbook promotes activities that first generate data related to source and site conditions that represent critical inputs, and then applies this information to the technology selection process. Matching the most appropriate technologies to the specific needs of the wastewater project is the key that leads to long term sustainability. How to Design Wastewater Systems for Local Conditions in Developing Countries is an invaluable resource for public sector decision makers and private sector service providers in developing countries. It is also a useful text for students at engineering colleges in developing countries interested in taking a class that teaches the methods of decentralized wastewater management system (DWMS) development.
Author: Elizabeth Tilley
Publisher:
ISBN: 9783906484570
Category :
Languages : en
Pages : 176
Get Book Here
Book Description
Author: Michael Cowen
Publisher:
ISBN:
Category : Literary Collections
Languages : en
Pages : 404
Get Book Here
Book Description
This volume contains electoral studies of multiparty politics in 14 African countries during the 1990s. Most are about national elections in Anglophone Africa. There are also less well-known examples from Sudan, Ethiopia and Guinea Bissau. The collection also features studies of the local elections in Namibia and of a significant by-election in Malawi. The multiparty period had been put, wherever possible, within the historical context of earlier elections in Africa. Questions addressed include: how did incumbent governing regimes learn to live with multiparty politics? Why have some elections been so closely fought and others have suffered from apathy? Why has there been relatively open political expression and activity when the elections have increased the political and economic manipulation by incumbent governments? Why have the elections of the 1990s been so marked by local and ethnic variations? To what extent did this wave of democracy result from pressure from donor countries?
Author: Clara Irazábal
Publisher: Routledge
ISBN: 1351951343
Category : Social Science
Languages : en
Pages : 389
Get Book Here
Book Description
Cities in both North and South America are confronting tremendous challenges in urban growth and management as they enter the new century. Curitiba in Brazil and Portland in Oregon, US are cities that have achieved recognition for exemplary urban planning programmes over the past three decades. As such, they provide particularly useful illustrations of the intense development pressures that many urban areas currently face. This book explores the dynamics of their urban governance, arguing that, in general, there has been a unique synergy derived from the combination of visionary leadership, innovative urban plans and effective citizen involvement. The book argues that, while urban design and architecture are key to the success in making cities livable and in augmenting the global reputations, such sensitive, innovative urban planning and design projects first need to be governed effectively and grounded within the specifics of their local cultures and existing built environments.
Author: Canada. Patent Office
Publisher:
ISBN:
Category : Copyright
Languages : en
Pages : 1070
Get Book Here
Book Description
Author: Claudia Haarmann
Publisher:
ISBN:
Category : Development projects
Languages : en
Pages : 112
Get Book Here
Book Description
