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This two‐part series describes an integrated experimental investigation. The first part is concerned with the determination of axial and radial solids concentration profiles at different superficial gas velocities for three columns having I.D. of 2.5, 6.5, and 9.5 in. respectively. The second part is concerned with steady state point source gas tracer experiments carried out in the 9.5‐in. column and in which the tracer concentration was measured at different radial positions above and below the injection source at various gas velocities Both parts are complimentary to each other for describing the internal flow behavior of the gas‐solid fluidized system.

Within the context of biogas R & D and demonstration project undertaken by the Egyptian National Resarch Centre, village demonstrations are of paramount importance. In this paper, a case study of a pioneering village demonstration is presented. Based on a preliminary sociological survey, “Al Manawat” ‐ a traditional Egyptian village was selected for the first demonstration. After a short orientation phase through which the biogas technology was introduced to a group of village representatives, a family was selected to conduct the demonstration experiment. Concomitant with the family energy requirements, availability of digester feed materials, site characteristics and other relevant factors, a family‐size unit of a modified Indian type was designed and erected by the side of the farmer's house. The digester effective volume is 9 cu.m. and is connected to both a latrine and animal shed. The unit has been successfully operated since May 1981. The highlights of the construction stage as well as the unit performance characteristics are discussed. A preliminary techno‐economic appraisal is also outlined. Finally, social impacts are assessed. Initial results indicate that under the Egyptian village conditions, and particularly with the heavily subsidized fuel prices, the high saving in manure transport attained through the introduction of the biogas unit, appears to be the main benefit from the farmer's point of view. Dans le cadre de la recherche et du développement du gaz de fermentation et d'un projet pilote entrepris par le Centre national de recherche égyptien, les démonstrations faites dans les villages occupent une place prépondérante. Dans cet article, l'auteur présente le cas‐type d'une démonstration pilote faite dans un village. En se basant sur une enquêue sociologique préliminaire, “Al Manawat”, qui est un village égyptien traditionnel, a été choisi comme lieu de la première démonstration. Après une courte phase d'orientation au cours de laquelle le technologie du gaz de fermentation a été présentée à un groupe de notables du village, on a choisi une famille pour effectuer la démonstration expérimentale. En même temps que l'on étudiait les besoins énergétiques de cette famille, la disponibilité de matières de base de fermentation, les caractéristiques de l'emplacement et tous autres facteurs pertinents, une unité familiale de type indien modifié a été conĉue et érigée à côté de la ferme. Le composteur, d'un volume utile de matières premières de 9 m3, est relié à la fois aux latrines et à l‘étable. Cette unité fonctionne avec satisfaction depuis le mois de mai 1981. L'article met en avant les points essentiels des étapes de la construction et les caractéristiques de rendement de l'unité de fermentation. Il esquisse une évaluation technico‐économique préliminaire et fait l'estimation des retombées sociales. Les premiers résultats montrent que, dans le cadre du village égyptien et particulièrement du fait que les prix du fuel sont largement subventionnés, les économies importantes réalisées dans le transport d...

The objective of this work is to develop a systematic approach to the optimal design and integration of seawater cooling systems in industrial facilities along with the usage and discharge of biocides. Specifically, the paper will address the following tasks: 2 A. B. Mahfouz et al. 1 identification of the reaction pathways for the biocide from the mixing basin to the discharge points 2 kinetic modelling of the biocide and by-products throughout the process 3 a process integration framework to provide a holistic approach to optimising the design and operation of the seawater cooling systems, along with the dosage and discharge systems.A hierarchical procedure is developed to first identify design modifications for heat integration and energy efficiency. Then, a multi-period, multi-segment optimisation formulation is developed and solved to identify the optimal operation and scheduling of biocide usage and discharge. A case study is solved to illustrate the applicability of the devised approach. (2012) 'A systems integration approach to the optimum operation and scheduling of biocide usage and discharge for seawater cooling systems', Int. Biographical notes: Abdullah Bin Mahfouz has obtained his PhD in ChemicalEngineering from Texas A&M University. His research is in the areas of sustainability, process integration, systems optimisation, resource and water conservation, and simultaneous energy and mass integration. He developed a novel approach to the design of seawater cooling systems and performing energy integration while optimising biocide usage and discharge. This state-of-the-art process integration research involves innovative optimisation formulations that reconcile the economic, energy and environmental objectives of the cooling system. Selma Atilhan has successfully defended her PhD in Water Resources Engineering Group at Texas A&M University. His research focuses on chemical processes associated with treatment of water, wastewater and hazardous wastes. His work includes development of innovative extensions of lime softening for removal of scalants for treatment of cooling water and desalination concentrates; discovery and development of a new class of treatment processes for chemical reduction of contaminants called advanced reduction processes; redox processes for destruction of chlorinated organics, nitrate and perchlorate; kinetic models for formation of halogenated by-products in drinking water and cooling water.Patrick Linke is a Professor of Chemical Engineering at Texas A&M University at Qatar and the Managing Director and Co-founder of the Qatar Sustainable Water and Energy Utilization Initiative (QWE), a centre of excellence for research and capacity building at Texas A&M University in A systems integration approach 3 Education City. He is a Process Systems Engineer and his activities focus on the design of efficient processes, integrated systems and associated infrastructures. He obtained his PhD from the University of Manchester (UMIST) in the UK.Ahmed Abdel-Wahab is an Associate Professor ...