Multitubular Reactor Exchanger For Fcc: Design And Kinetic Modelling

A pilot plant unit, namely Multicrackex, for the catalytic cracking of hydrocarbons with the riser and regenerator units under direct heat exchange conditions was designed, built and operated. The heat transfer process, between regenerator and reactor, was achieved by placing the riser reactor inside the regenerator, with an arrangement similar to the one of a bundle of tubes in a heat exchanger.;The regenerator of the Multicrackex unit had an outside diameter of 0.2667 m and a height of 3.25 m. The riser had an outside diameter of 0.0334 m and a total height of 3.460 m.;A two levels pseudo-factorial design was selected for the experimental program. Targeted factor levels were: (i) 580-730{dollar}\sp\circ{dollar}C temperature range in the regenerator, (ii) 1.5-4.0 s contact times, defined at riser entry conditions and (iii) 1.0-12.0 catalyst-to-oil ratios. A synthetic gas oil SF-135 (CANMET) and a commercial equilibrium catalyst, Octaboost 6XX Series (Akzo) were used during the operation of the unit.;Superimposing the experimental temperature profile inside the riser, reaction rate constants and activations energies, associated with three and four lumps models, were simultaneously evaluated with a high degree of precision ({dollar}\pm{dollar}7% average) and relatively low correlation.;It was successfully demonstrated that given heat transfer conditions, both endothermic effects of the cracking reactions and gas oil vaporization were substantially neutralized by the heat fluxes from the regenerator. Thus, the significant heat exchange was represented with a film coefficient assigned to the gas-solid suspension (riser side) of the riser-regenerator system. A heat transfer correlation was proposed to model this coefficient. Simulation results obtained from the simultaneous application of kinetic and heat transfer parameters were inside the {dollar}\pm{dollar}15 to 20% relative errors range.;Results obtained demonstrate that heat transfer conditions in the Multicrackex unit provide a unit of extreme flexibility. High temperature conditions can be selected to produce a high fraction of light gases with significant amounts of C{dollar}\sb3{dollar}-C{dollar}\sb4{dollar} olefin and a controlled coke yield. On the other hand, model predictions indicated that operating conditions can be adjusted to maximize gasoline yields at high temperatures and short contact times (about 150 milliseconds).;Consequently, heat transfer conditions between riser and regenerator made it possible to control selectivity to gasoline or light gases formation. Moreover, light gases fractions with high content of butenes were also obtained in encouraging amounts. These fractions are excellent feedstock for alkylation units and consequently for the production of reformulated gasolines

Diabete tipo 2 e obesità pediatrica: rassegna a cura dei Gruppi di Studio Obesità Infantile e Diabete della Società Italiana di Endocrinologia e Diabetologia Pediatrica

L’obesità pediatrica è una condizione a elevato rischio di alterazioni del metabolismo glicidico, che con il tempo possono evolvere in diabete tipo 2 (T2D). Tali condizioni, prevalentemente caratterizzate in età pediatrica da alterata glicemia a digiuno e/o ridotta tolleranza al glucosio, sono definite come “prediabete”. Un panel di esperti dei gruppi di studio Obesità Infantile e Diabete della Società Italiana di Endocrinologia e Diabetologia pediatrica ha condotto una revisione delle più recenti evidenze scientifiche sulla condizione di prediabete e di diabete tipo 2 nell’obesità pediatrica. In questa rassegna sono descritti i fattori di rischio del prediabete e del T2D, l’epidemiologia, la diagnosi, il trattamento, le complicanze associate e la prevenzione. La prevenzione e la cura dell’obesità pediatrica rappresentano obiettivi di fondamentale importanza al fine di ridurre le alterazioni del metabolismo glicidico associate. Studi futuri dovranno identificare marcatori predittivi di T2D, in aggiunta al dato anamnestico della familiarità, che rimane di grande supporto per tale diagnosi

Diabete tipo 2 e obesit\ue0 pediatrica: rassegna a cura dei Gruppi di Studio Obesit\ue0 Infantile e Diabete della Societ\ue0 Italiana di Endocrinologia e Diabetologia Pediatrica

L\u2019obesit\ue0 pediatrica \ue8 una condizione a elevato rischio di alterazioni del metabolismo glicidico, che con il tempo possono evolvere in diabete tipo 2 (T2D). Tali condizioni, prevalentemente caratterizzate in et\ue0 pediatrica da alterata glicemia a digiuno e/o ridotta tolleranza al glucosio, sono definite come \u201cprediabete\u201d. Un panel di esperti dei gruppi di studio Obesit\ue0 Infantile e Diabete della Societ\ue0 Italiana di Endocrinologia e Diabetologia pediatrica ha condotto una revisione delle pi\uf9 recenti evidenze scientifiche sulla condizione di prediabete e di diabete tipo 2 nell\u2019obesit\ue0 pediatrica. In questa rassegna sono descritti i fattori di rischio del prediabete e del T2D, l\u2019epidemiologia, la diagnosi, il trattamento, le complicanze associate e la prevenzione. La prevenzione e la cura dell\u2019obesit\ue0 pediatrica rappresentano obiettivi di fondamentale importanza al fine di ridurre le alterazioni del metabolismo glicidico associate. Studi futuri dovranno identificare marcatori predittivi di T2D, in aggiunta al dato anamnestico della familiarit\ue0, che rimane di grande supporto per tale diagnosi

Signos Distintivos Colectivos en Latinoamérica: Fomento del Desarrollo Valorando Origen y Calidad (Distinctive Signs for Collective Use in Latin America: Development Promotion by Valuing Origin and Quality)

La producción desarrollada localmente, incluyendo la manufactura, la artesanía y especialmente la producción de alimentos en los países latinoamericanos, es esencial para sus economías. Los sistemas de diferenciación de la calidad, como las indicaciones geográficas, las denominaciones de origen, las marcas colectivas y de certificación, y los sellos de calidad, entre otros, pueden desempeñar un doble papel, tanto para el desarrollo económico y social de la región como para añadir valor a sus productos con el consiguiente impacto en el comercio. Sin embargo, estos sistemas tienen particularidades en cada país debido a las múltiples realidades existentes. Es por ello que constituye un desafío promover a integración, la armonización y/o la cooperación al interior de la región. Es en este sentido que el presente documento ofrece un estudio comparado de las reglas jurídicas vigentes y de cómo funcionan estos sistemas en Argentina, Brasil, Chile, Colombia, Costa Rica, México, Paraguay, Perú y Uruguay para respaldar la investigación y la elaboración de leyes y políticas públicas en la materia. El resultado indica las posibles vías de avance, centrándose especialmente (a) en el potencial de un sistema regional de reconocimiento mutuo de la protección dada a nivel nacional (b) en la mejora del sistema a nivel nacional, según la realidad de cada país y las necesidades de los productores.Origin-based production, including manufacturing, handicraft, and especially food production in Latin American countries, is essential to their economies. Quality differentiation systems such as geographical indications, designations of origin, collective and certification marks, and quality labels, among others, can play a dual role in the economic and social development of the region and in adding value to their products with the consequent impact on trade. However, those systems are quite particular to each country due to multiple realities. Therefore, it is challenging to promote integration, harmonisation, and /or cooperation within the region. Therefore, this paper aims to offer a comprehensive legal comparative understanding of how those systems work in Argentina, Brazil, Chile, Colombia, Costa Rica, Mexico, Paraguay, Peru, and Uruguay to back up further research, law, and policy-making on this field. The outcome indicates potential ways forward, targeting especially (a) the potential of a regional system of mutual recognition of the protection granted at the national level and (b) the improvement of the system at the domestic level, according to each country's reality and producer's needs

Distinctive Signs for Collective Use in Latin America: Development Promotion by Valuing Origin and Quality

Origin-based production, including manufacturing, handicraft, and especially food production in Latin American countries, is essential to their economies. Quality differentiation systems such as geographical indications, designations of origin, collective and certification marks, and quality labels, among others, can play a dual role in the economic and social development of the region and in adding value to their products with the consequent impact on trade. However, those systems are quite particular to each country due to multiple realities. Therefore, it is challenging to promote integration, harmonisation, and /or cooperation within the region. Therefore, this paper aims to offer a comprehensive legal comparative understanding of how those systems work in Argentina, Brazil, Chile, Colombia, Costa Rica, Mexico, Paraguay, Peru, and Uruguay to back up further research, law, and policy-making on this field. The outcome indicates potential ways forward, targeting especially (a) the potential of a regional system of mutual recognition of the protection granted at the national level and (b) the improvement of the system at the domestic level, according to each country's reality and producer's needs