Reactive distillation:The front-runner of industrial process intensification - A full review of commercial applications, research, scale-up, design and operation

Most industrial scale reactive distillations (presently more than 150), operated worldwide today at capacities of 100-3000 ktonnes/y, and are reported in this paper. Most of these plants started up less than 15 years ago. The drivers, processes, systems, scale-up methods and partner collaborations for this rapid invasion of a new process intensified technique are explained in this paper. The business drivers are (a) economical (prosperity): variable cost, capital expenditure and energy requirement reduction. In all cases these are reduced by 20% or more, when compared to the classic set-up of a reactor followed by distillation. (b) Environmental (planet): lower emissions to the environment. In all cases carbon dioxide and diffusive emissions are reduced and (c) social (people): improvements on safely, health and society impact are obtained by lower reactive content, lower run away sensitivity and lower space occupation. These industrial reactive distillation systems comprise homogeneous and heterogeneous catalysed, irreversible and reversible reactions, covering large ranges of reactions, notably hydrogenations, hydrodesulfurisation, esterifications and etherification. Various commercial methods for packing heterogeneous catalyst in columns are now available. The systems comprise amongst others: multiple catalyst systems, gas and liquid internal recycle traffic over these catalyst systems, separation, mass flow, and enthalpy exchange. These are integrated optimally in a single vessel, a characteristic feature of process intensification. The scale-up methods applied from pilot plants to commercial scale are brute force and modelling. Technology providers CDTECH and Sulzer Chemtech have used these scale-up methods successfully. Barriers perceived and real have also been removed by these companies. Chemical manufacturing companies have also developed their own specific reactive distillations by their own research and development. These companies, both on their own and in consortia, also developed heuristic process synthesis rules and expert software to identify the attractiveness and technical feasibility of reactive distillation. Heuristic rules and expert software will be presented and supported by examples. Academic research also produced design methods to identify the feasibility of reactive distillation, to determine the feed locations, to select packing types, to sequence columns optimally and also produced methods to design, optimise and control the columns with steady state and dynamic simulation models. The rapid commercial scale implementation of reactive distillation by co-operation of partners in research, scale-up, design and reliable operation can also be seen as a model for rapid implementation of other process intensification techniques in the chemical industry. (C) 2007 Elsevier B.V. All fights reserved

Gravitino fields in Schwarzschild black hole spacetimes

The analysis of gravitino fields in curved spacetimes is usually carried out using the Newman-Penrose formalism. In this paper we consider a more direct approach with eigenspinor-vectors on spheres, to separate out the angular parts of the fields in a Schwarzschild background. The radial equations of the corresponding gauge invariant variable obtained are shown to be the same as in the Newman-Penrose formalism. These equations are then applied to the evaluation of the quasinormal mode frequencies, as well as the absorption probabilities of the gravitino field scattering in this background.Comment: 21 pages, 2 figures. arXiv admin note: text overlap with arXiv:1006.3327 by other author

Industrial best practices of conceptual process design

Abstract The chemical process industry aims particularly at energy, capital expenditure and variable feedstock cost savings due to fierce global competition, the Kyoto Protocol and requirements for sustainable development. Increasingly conceptual process design methods are used in the industry to achieve these aims. They are used in: • existing processes to renew parts; • process re-designs based on existing feedstocks and catalysts; • innovative processes (new feed stocks, new catalysts, new process routes, new multifunctional equipment). This article is focused on the best industrial conceptual design practices applied for these application areas. To this end we have reviewed methods, which are used in the chemical process industry in the last 15 years. Capital, energy and variable cost savings are indicated for each method. Specific attention is paid to: • functional integration to multi-functional equipment; • heuristic based selection of unit operations and recycle structure; • superstructure based design optimisation with mixed-integer-non-linear programming (MINLP)

Desarrollo de modelos lineales para la determinación del área foliar en habichuela (Phaseolus vulgaris L.) a partir de medidas directas de hojas

Plant leaf area is an important physiological trait, and direct, non-destructive methods for estimating leaf area have been shown to be effective while allowing for repeated plant sampling.The objective of this study was to evaluate direct, non-destructive leaflet measurements as predictors of actual leaflet area (LA), to test previously developed models, and to develop genotype-specific linear models for leaflet area estimation in common bean (Phaseolus vulgaris L.). For development of appropriate regression models for leaflet area estimation, four common bean genotypes were evaluated under greenhouse conditions: BAT 477, 'Morales', SER 16, and SER 21. The greenhouse-derived models were evaluated under field conditions. Previously developed models were tested and found to overestimate or underestimate leaflet area. Leaflet measurements included maximum leaflet width (W) and maximum leaflet length (L) and L X W. The measurements with the highest values for the coefficient of determination (R2) were W or L X W for BAT 477, SER 16, and Morales (0.97, 0.95, and 0.95, respectively), and L X W for SER 21 (R2 = 0.96). The linear models developed were shown to be effective and robust for predicting leaflet area under both greenhouse and field conditions during both vegetative and reproductive stages of plant development.El área foliar es una medida importante de la fisiología de las plantas, y los métodos indirectos y no-destructivos para medir el área foliar han demostrado ser muy eficientes a la vez que permiten la toma de medidas repetidas en el tiempo. El objetivo del presente estudio fue evaluar directamente métodos no destructivos para la estimación del área foliar en habichuelas (Phaseolus vulgaris L.) a partir de la medida de las hojas, probar modelos previos, y desarrollar modelos lineales específicos para cada genotipo. Se evaluaron cuatro genotipos: BAT 477, Morales, SER 16, y SER 21, bajo condiciones de invernadero y de campo. Los modelos desarrollados en invernadero se aplicaron y evaluaron bajo condiciones de campo durante dos años. Los modelos previos reportados por otros autores fueron evaluados, y se encontró que sobre-o sub-estimaban el área foliar. Los modelos desarrollados en este estudio incluyeron el ancho máximo de la hoja (W), y la longitud máxima (L), los que fueron empleados para calcular un tercer factor, L X W. Los modelos con mayores coeficientes de determinación (R2) fueron W or L X W para BAT 477, SER 16 y Morales (0.97, 0.95, y 0.95, respectivamente) y L X W para SER 21 (R2 = 0.96). Los modelos de regresión desarrollados mostraron ser eficientes en la predicción del área foliar bajo condiciones de campo e invernadero, en las fases vegetativas y reproductivas, para cada uno de los genotipos evaluados

Descripción de una nueva especie del género Arganiella Giusti y Pezzoli, 1980 (Mollusca, Gastropoda, Hydrobiidae) en la Península Ibérica

10 pages, 4 figures, 5 tables.[EN] A new species of Arganiella Giusti & Pezzoli, 1980, up to now a monotypic genus, thought to be endemic to the Italian Central Apennines, is described from the Iberian Peninsula. This new species, named Arganiella tartessica, is located in southwestern Spain, provinces of Huelva and Badajoz. In this paper, a detailed description of its morphological characters is given and new data of nervous system and ciliated areas in the cephalic region are provided.[ES] Se describe una especie ibérica de Arganiella Giusti y Pezzoli, 1980, un género que hasta ahora se consideraba monotípico y endémico de los Apeninos centrales italianos. Esta nueva especie, denominada Arganiella tartessica, ha sido localizada en el sureste español, en las provincias de Huelva y Badajoz. En este artículo se describen en detalle sus caracteres morfológicos y se presentan datos, hasta la fecha desconocidos en el género Arganiella, del sistema nervioso y de áreas ciliadas en la región cefálica.This work was funded by the “Fauna Ibérica” Project (DGES PB95–0235).Peer reviewe