Simulation of a spouted bed reactor for solid catalyst alkylation

Nieto, Osmary; Niño, Mariana; Martínez, Roxana; Tailleur, Roberto Galiasso

doi:10.1016/j.fuel.2006.12.007

Cited by 9 publications

(1 citation statement)

References 9 publications

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“…Two processes are in use worldwide, using respectively hydrogen fluoride (HF) and sulphuric acid as catalyst (Wood et al, 2001;Nieto et al, 2007); globally, total outputs from the two processes are almost equal (DuPont STRATCO, 2006). There are relatively few configurations of alkylation units, the primary differences being between the major licensors: UOP and ConocoPhillips (previously Phillips) for HF units, and DuPont/STRATCO and ExxonMobil for H 2 SO 4 units.…”

Section: Existing Alkylation Process and Waste Managementmentioning

confidence: 99%

Assessment of cleaner process options: A case study from petroleum refining

et al. 2008

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Assessment of process changes to reduce, recycle or avoid wastes requires attention to systems which are broader than the immediate process; that is, it is necessary to take a life cycle perspective. Definition of the system boundary for such an assessment can be problematic in itself. A real case study is presented to illustrate the problem of assessing clean technologies: possible modifications to an alkylation unit at a UK refinery. The process uses hydrogen fluoride as alkylation catalyst, and generates fluoridic wastes which are hazardous and require treatment both onand off-site. Possible changes to avoid, reduce or enable partial recycling of the waste are identified, representing different levels of change in the process and therefore requiring assessment with different system boundaries. The different system definitions lead to differences in the ways data must be compiled for quantitative environmental life cycle assessment, and in the range of stakeholders explicitly or implicitly involved in assessing and implementing the changes. The case study demonstrates some of the less familiar challenges introduced by the "pollution prevention" or "clean technology" paradigms of chemical processing.L'évaluation des modifications apportées dans les procédés dans le but de réduire, recycler ouéviter les gaspillages nécessite qu'on prête attention aux systèmes plutôt qu'aux procédés eux-mêmes, en ce sens qu'il faut travailler dans une perspective de cycle de vie. La définition de la limite de système pour une telleévaluation peutêtre problématique en soi. Uneétude de cas réelle est présentée pour illustrer le problème de l'évaluation de techniques propres; il s'agit de modifications possiblesà une unité d'alkylation dans une usine du Royaume-Uni. Le procédé emploie du fluorure d'hydrogène comme catalyseur d'alkylation et produit des déchets fluorés qui sont dangereux et qui nécessitent un traitement sur le site et en-dehors du site. Des changements possibles pouréviter ou réduire les déchets ou permettre leur recyclage sont identifiés; ils correspondentà différents niveaux de changements dans le procédé, et par conséquent, requièrent l'évaluation de différentes limites de systèmes. Les différentes définitions de système mènentà des différences dans la manière de compiler les données pour l'évaluation des cycles de vie environnementaux quantitatifs, et dans la manière de traiter les parties prenantes explicitement ou implicitement impliquées dans l'évaluation et la mise en oeuvre de ces changements. L'étude de cas illustre certains des défis les moins familiers introduits par les concepts prévention de la pollution ou technologie propre dans le génie des procédés.Keywords: clean technology, waste minimization, process selection, life cycle management, alkylation INTRODUCTIONThe Paradigm Shift in Chemical Processing O ver roughly the last two decades, there has been a shift in both thinking and practice away from the "clean-up" or "end-of-pipe" technology approach which had replaced the "dilute-and-disperse" approac...

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Section: Existing Alkylation Process and Waste Managementmentioning

confidence: 99%

Assessment of cleaner process options: A case study from petroleum refining

et al. 2008

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Alkylation—Heterogeneous

Martı́nez

Corma

Prieto

et al. 2011

Encyclopedia of Catalysis

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Alkylate or alkylation gasoline is produced by reacting isobutane with light olefins, generally the C 3 –C 4 cut from catalytic cracking (FCC) units, in the presence of a strong acid catalyst. The alkylate product is mostly composed of a mixture of high octane isoparaffins being almost free of sulfur, olefins, and aromatics, thus making it a valuable component of reformulated gasoline. Unfortunately, today's commercial alkylation processes rely on the use of noxious HF and H 2 SO 4 liquid acids as catalysts and this imposes serious limitations, especially in the case of HF‐catalyzed processes, to expanding the worldwide alkylation capacity to the levels one might ideally envisage. This prompted to an intensive research work in the past 30 years in both academy and industry looking for alternative environment friendly solid acid catalysts that overcome the limitations of the current alkylation technologies. Since then, different types of solid acids, among which zeolites have deserved particular attention, have been investigated leading to outstanding advances in both catalyst and process design as well as in fundamental knowledge (nature of active sites, mechanism, etc.) that allowed several solid acid alkylation technologies being, at present, offered for commercialization. Unfortunately, refiners are still reluctant to assume the economic risks associated with the installation of a new alkylation technology, even if competitive, unless tighter environmental regulations become operational. In this article, the latest achievements in the use of green solid acid catalysts as potential alkylation catalysts are reviewed. After a short introduction, the main features of the different solid acids so far studied, including supported Brønsted and Lewis acids, acid resins both supported and unsupported, zeolites, sulfated and tungstated transition metal oxides, and heteropolyacids and related materials, in the alkylation reaction are addressed. Although they cannot be considered as true solid acids, the potential of ionic liquids as alkylation catalysts is also discussed. Finally, a brief description of the different solid acid alkylation processes so far developed is included, with special emphasis on the catalyst and reactor designs.

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Computational investigation of contraction behavior in a liquid-solid fluidized bed

et al. 2012

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Contraction beha ior of a liquid-solid fluidized bed has been in estigated numerically. ased on a sim le hydrodynamic model ro osed by randani and hang (2006), a case study for solid articles with a density of ,000 g m and a diameter of 2.5 10m is simulated in a two-dimensional uidized bed (0.50 m height and 0.10 m width). Due to the continuity of numerical com utation, there is a transition region between two zones of different solid holdu s when the liquid elocity is suddenly changed. he to , middle and bottom interfaces are e lored to obtain a reasonable interface height. he simulated results show that the steady time of the middle interface is more close to Gibilaro's theory and suitable for describing the contraction rocess of a hase interface. urthermore, the effect of liquid elocity and article diameter is simulated in the other two-dimensional fluidized bed (0.10 m height and 0.02 m width) where the solid articles are glass beads whose ro erties are similar to those of the catalyst articles used in the al ylation rocess. he results also show good agreement with Gibilaro's theory, and that larger articles lead to a more ob ious bed contraction.

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Simulation of a spouted bed reactor for solid catalyst alkylation

Cited by 9 publications

References 9 publications

Assessment of cleaner process options: A case study from petroleum refining

Assessment of cleaner process options: A case study from petroleum refining

Alkylation—Heterogeneous

Computational investigation of contraction behavior in a liquid-solid fluidized bed

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