Liquid-solid Contacting in Trickle-bed Reactors PDF Download
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Author: Arjan Van Houwelingen
Publisher:
ISBN:
Category : Colorimetric analysis
Languages : en
Pages : 204
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Book Description
Author: Arjan Van Houwelingen
Publisher:
ISBN:
Category : Colorimetric analysis
Languages : en
Pages : 204
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Book Description
Author: John Gerald Schwartz
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 512
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Book Description
Author: Karthik Balakrishnan
Publisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages : 7
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Book Description
Author: Vivek V. Ranade
Publisher: Elsevier
ISBN: 0080931448
Category : Technology & Engineering
Languages : en
Pages : 285
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Book Description
This book provides a hybrid methodology for engineering of trickle bed reactors by integrating conventional reaction engineering models with state-of-the-art computational flow models. The content may be used in several ways and at various stages in the engineering process: it may be used as a basic resource for making appropriate reactor engineering decisions in practice; as study material for a course on reactor design, operation, or optimization of trickle bed reactors; or in solving practical reactor engineering problems. The authors assume some background knowledge of reactor engineering and numerical techniques. - Facilitates development of high fidelity models for industrial applications - Facilitates selection and application of appropriate models - Guides development and application of computational models to trickle beds
Author: Patrick L. Mills
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 664
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Book Description
Author: Arjan J. Van Houwelingen
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Trickle-flow is traditionally modeled by means of hydrodynamic parameters such as liquid holdup, two-phase pressure drop and wetting efficiency. Several studies showed that these parameters are not only a function of flow conditions and bed properties, but also of the flow history and morphology of flow. These can have a major influence on the distribution in the bed. The effect of flow morphology on liquid holdup and pressure drop is widely discussed in literature, but little attention is paid to its effect on wetting efficiency. Trickle-bed reactor models suggest that not a only bed-averaged but also the distribution of wetting efficiency may be of importance for reactor performance. Both the average wetting efficiency and the distribution of wetting are probably a function flow history and morphology. The distribution of wetting efficiency for different flow morphologies were investigated by means of a colorometric method that was developed for this purpose. Representative wetting distributions could be obtained. Flow morphologies and liquid distributions were manipulated by means of the pre-wetting procedure that was performed prior to flow. Pulse and Levec pre-wetted beds were investigated. These distributions were explained in detail in terms of flow morphology. It was found that the average wetting efficiency in pulse pre-wetted beds are much higher than in Levec pre-wetted beds. All particles in the pulse pre-wetted beds at all investigated flow conditions were contacted by the flowing liquid. This was not the case for the Levec pre-wetted beds. It was found that the flow in Levec pre-wetted beds become similar to that in pulse pre-wetted beds at high liquid flow rates. It was investigated how these distributions can affect reactor modeling, based on popular particle-scale models that relate reactor efficiency to wetting efficiency. According to these models, the wetting efficiency distribution in pulse pre-wetted beds can be characterised by means of only its average value. This is not the case for Levec pre-wetted beds. These results are however a strong function of the models that were employed. Finally, some recommendations are made in terms of the preferred pre-wetting method or flow morphology for different types of reactions. These recommendations are also based on models and have not been verified with experiments.
Author: Hugo de Lasa
Publisher: Springer Science & Business Media
ISBN: 9400944004
Category : Science
Languages : en
Pages : 839
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Book Description
Today's frustrations and anxieties resulting from two energy crises in only one decade, show us the problems and fragility of a world built on high energy consumption, accustomed to the use of cheap non-renewable energy and to the acceptance of eXisting imbalances between the resources and demands of countries. Despite all these stressing factors, our world is still hesitatins about the urgency of undertaking new and decisive research that could stabilize our future, Could this trend change in the near future? In our view, two different scenarios are possible. A renewed energy tension could take place with an unpredictable timing mostly related to political and economic factors, This could bring again scientists and technologists to a new state of shock and awaken our talents, A second interesting and beneficial scenario could result from the positive influence of a new generation of researchers that with or without immediate crisis, acting both in industry and academia, will face the challenge of developing technologies and processes to pave the way to a less vulnerable society, Because Chemical Reactor Design and Technology activities are at the heart of these required new technologies the timeliness of the NATO-Advanced Study Institute at the University of Western Ontario, London, was very appropriate.
Author: P. A. Ramachandran
Publisher: Gordon & Breach Publishing Group
ISBN:
Category : Science
Languages : en
Pages : 448
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Author: Rita Joubert
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Hydrodynamic multiplicity in the trickle flow, or low interaction, regime is a well documented phenomenon. Multiple hydrodynamic states are often presented in the form of hysteresis loops where the hydrodynamic parameter studied are shown as a function of the operating history of the bed, i.e. liquid and gas flow rates. In extreme cases the lower leg, representing an increase in liquid flow rate on a pre-wetted and drained bed, is commonly referred to as the Levec mode. The upper extreme, referred to as the Kan-liquid mode, represents a decrease in liquid flow rate after operation in the high interaction regime. The many reported studies investigating liquid-solid mass transfer in trickle beds have generally used either the dissolution or electrochemical techniques. Numerous researchers have used their data to develop correlations predicting solid-liquid mass transfer coefficients. Most of these studies do not specify the multiplicity mode of operation. Only two studies (Sims et al. (1993) and Van der Merwe, Nicol & Al-Dahhan (2008)) use both the Levec and Kan-liquid operating modes. Both of these studies suggest that solid-liquid mass transfer also exhibit multiplicity behaviour although the trends suggested or speculated differ from each other. Sims et al. (1993) found that a Kan-liquid operated bed will outperform a Levec operated bed: however in contrast to this Van der Merwe et al. (2008) speculated that a Levec operated bed is better suited for liquid limited reactions due to enhanced liquid-solid mass transfer in the Levec mode as a result of faster interstitial velocity. This study showed that solid-liquid mass transfer coefficients, measured with both the dissolution and electrochemical technique, show multiplicity behaviour. Two distinct operating regions were found, which corresponds to the Levec and Kan-liquid modes. Measurements taken using the electrochemical technique yielded solid-liquid mass transfer coefficients larger than those measured using the dissolution method. The experimental results agree with the trend found by Sims et al. (1993) but the mass transfer coefficients in this study were significantly lower. Additionally it was shown that the difference in mass transfer coefficients, in the two modes, cannot be explained by merely compensating for the differences in wetting efficiency and interstitial velocity, suggesting that the Levec mode has a larger percentage of stagnant or poorly irrigated zones. It was also shown that mass transfer coefficients measured at the top of the column is higher than those measured at the bottom, suggesting that the flow structure is changing as a function of axial length. Lastly, with regards to electrochemical measurements of liquid-solid mass transfer, it was shown that measurements using a single particle electrode compared well to that of a multiple packing electrode.
Author: Sunil S Joshi
Publisher: Elsevier
ISBN: 0128016701
Category : Technology & Engineering
Languages : en
Pages : 784
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Book Description
Industrial Catalytic Processes for Fine and Specialty Chemicals provides a comprehensive methodology and state-of-the art toolbox for industrial catalysis. The book begins by introducing the reader to the interesting, challenging, and important field of catalysis and catalytic processes. The fundamentals of catalysis and catalytic processes are fully covered before delving into the important industrial applications of catalysis and catalytic processes, with an emphasis on green and sustainable technologies. Several case studies illustrate new and sustainable ways of designing catalysts and catalytic processes. The intended audience of the book includes researchers in academia and industry, as well as chemical engineers, process development chemists, and technologists working in chemical industries and industrial research laboratories. - Discusses the fundamentals of catalytic processes, catalyst preparation and characterization, and reaction engineering - Outlines the homogeneous catalytic processes as they apply to specialty chemicals - Introduces industrial catalysis and catalytic processes for fine chemicals - Includes a number of case studies to demonstrate the various processes and methods for designing green catalysts
