Literature Review on Pressure Drop, Hold-up, Hydrodynamics and Mass Transfer in Trickle-bed Reactors PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Literature Review on Pressure Drop, Hold-up, Hydrodynamics and Mass Transfer in Trickle-bed Reactors PDF full book. Access full book title Literature Review on Pressure Drop, Hold-up, Hydrodynamics and Mass Transfer in Trickle-bed Reactors by V. Tarvo. Download full books in PDF and EPUB format.
Author: V. Tarvo
Publisher:
ISBN: 9789512260119
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: V. Tarvo
Publisher:
ISBN: 9789512260119
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Dylan Loudon
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
The prewetting of a trickle-bed reactor has important implications in the design and operation of these reactors. This is because the prewetting changes the flow morphology (shape and texture) of the liquid flowing through the bed and leads to the existence of multiple hydrodynamic states. The extent of this change in flow morphology can be seen in the effect the prewetting of the reactor has on the pressure drop, liquid holdup and gas-liquid mass transfer. The following prewetting procedures were used: -- Levec-wetted: the bed is flooded and drained and after residual holdup stabilisation the gas and liquid flow is reintroduced -- Kan-wetted: the bed is operated in the pulse flow regime and liquid and gas flow rates are reduced to the desired set point -- Super-wetted: the bed is flooded and gas and liquid flow are introduced once draining commences For the pressure drop: -- The different prewetting procedures resulted in two distinct regions (Upper region Kan and Super-wetted, Lower region Dry and Levec-wetted) -- There was no significant difference between the Dry and Levec-wetted beds -- The pressure drop in the Kan and Super-wetted beds can be as much as seven times greater than the pressure drop in the Dry and Levec-wetted beds For the liquid holdup: -- The different prewetting procedures resulted in four distinct regions (Kan-wetted, Super-wetted, Levec-wetted, Dry bed) -- The liquid holdup in the Kan-wetted bed can be as much as four times greater than the liquid holdup in the Dry bed -- The liquid holdup in the Levec-wetted can be as much as thirty percent lower than the liquid holdup in the Kan-wetted bed For the gas-liquid mass transfer: -- The different prewetting procedures resulted in three distinct regions (Kan and Super-wetted, Levec-wetted, Dry bed) -- The volumetric gas-liquid mass transfer coefficient in the Kan and Super-wetted beds can be as much as six times greater than the mass transfer coefficient in the Dry bed -- The volumetric gas-liquid mass transfer coefficient in the Kan and Super-wetted beds can be as much as two and a half times greater than the mass transfer coefficient in the Levec-wetted bed While an increase in the liquid flow rate results in an increase in the pressure drop, liquid holdup and gas-liquid mass transfer for all of the experiments, the effect of increasing gas flow on the measured variables were more pronounced for the prewetted beds. In a prewetted bed (Kan, Super and Levec-wetted) an increase in the gas flow rate causes an increase in the volumetric gas-liquid mass transfer coefficient and a decrease in the liquid holdup. The decrease in the liquid holdup is due to the fact that the increased gas flow rate causes the films around the particles to thin and spread out. In the dry bed the flow is predominantly in the form of rivulets and the increase in gas flow rate does not affect the liquid holdup. In the case of the volumetric gas-liquid mass transfer coefficient the increased gas flow rate causes an increase in the mass transfer coefficient regardless of the prewetting procedure. This increase is due to the effect that the gas flow rate has on the liquid holdup as well as the increase in the gas-liquid interfacial area due to the increased gas-liquid interaction. If the pulsing in the Kan-wetted bed is induced by increasing the gas flow rate and keeping the liquid flow rate constant the results are significantly different. The pressure drop in the gas-pulsing experiments was lower than the pressure drop in the recorded in the Kan and Super-wetted beds, but higher than the pressure drop in the dry and Levec-wetted beds. However, the liquid holdup in the gas-pulsing experiments was higher than the liquid holdup in any of the other beds. The volumetric gas-liquid mass transfer coefficient in the gas-pulsing experiments was lower than the mass transfer coefficients of the Kan and Super-wetted beds, but higher than the mass transfer coefficients in the dry and Levec-wetted beds. The multiple operating points obtained from the different prewetting procedures are by no means the only possible operating points. By simply decreasing the draining time in the Levec-wetted bed steady state operating points can be found between those of the Super and Levec-wetted beds. This alludes to the fact that the operating conditions determined from the different prewetting modes are only boundaries and that the actual operating point can lie anywhere between these boundaries. The existence of these multiple hydrodynamic states complicates things further when a correlation is developed to determine the pressure drop, liquid holdup or the volumetric gas-liquid mass transfer coefficient. No correlation tested was able to accurately predict the pressure drop, liquid holdup or volumetric gas-liquid mass transfer coefficient in the dry or prewetted beds.
Author: Subrata Kumar Majumder
Publisher: CRC Press
ISBN: 1351249851
Category : Science
Languages : en
Pages : 244
Get Book Here
Book Description
Slurry bubble column reactors are intensively used as a multiphase reactor in the chemical, biochemical, and petrochemical industries for carrying out reactions and mass transfer operations in which a gas, made up of one or several reactive components, comes into contact or reacts with a liquid. This volume describes the hydrodynamics of three-phase gas-liquid-solid flow in a downflow slurry bubble column. The efficiency of the downflow gas interacting system is characterized by the self-entrainment of secondary gas. The book covers the gas entrainment phenomena, gas holdup characteristics, pressure drop, gasliquid mixing characteristics, bubble size distribution, interfacial phenomena, and the mass transfer phenomena in the downflow slurry system. This volume will be useful in chemical and biochemical industries and in industrial research and development sectors, as well as in advanced education courses in this area. The book will be helpful for further understanding the multiphase behavior in gas interacting multiphase systems for research and development. The hydrodynamic and mass transfer characteristics discussed will be useful in the design and installation of the modified slurry bubble column in industry for specific applications.
Author: Nikolai Kolev
Publisher: Elsevier
ISBN: 0080463924
Category : Technology & Engineering
Languages : en
Pages : 709
Get Book Here
Book Description
Packed bed columns are largely employed for absorption, desorption, rectification and direct heat transfer processes in chemical and food industry, environmental protection and also processes in thermal power stations like water purification, flue gas heat utilization and SO2 removal. These Separation processes, are estimated to account for 40%-70% of capital and operating costs in process industry. Packed bed columns are widely employed in this area. Their usage also for direct heat transfer between gas and liquid, enlarge their importance. They are the best apparatuses, from thermodynamical point of view, for mass and heat transfer processes between gas and liquid phase. Their wide spreading is due to low capital investments and operating costs. Since 1995 there has not been published a specialised book in this area, and this is a period of quick development of packed columns. Packed Bed Columns reflects the state of this field including the author's experience on creating and investigating of new packings, column internals and industrial columns. - Considers the theories of mass transfer processes and shows how they help the construction of highly effective packings - Complete information about the performance characteristics of different modern types of highly effective packings - Considers the models for calculation and areas of their application
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721802395
Category :
Languages : en
Pages : 28
Get Book Here
Book Description
Packed bed reactors are well known for their vast and diverse applications in the chemical industry; from gas absorption, to stripping, to catalytic conversion. Use of this type of reactor in terrestrial applications has been rather extensive because of its simplicity and relative ease of operation. Developing similar reactors for use in microgravity is critical to many space-based advanced life support systems. However, the hydrodynamics of two-phase flow packed bed reactors in this new environment and the effects of one physiochemical process on another has not been adequately assessed. Surface tension or capillary forces play a much greater role which results in a shifting in flow regime transitions and pressure drop. Results from low gravity experiments related to flow regimes and two-phase pressure drop models are presented in this paper along with a description of plans for a flight experiment on the International Space Station (ISS). Understanding the packed bed hydrodynamics and its effects on mass transfer processes in microgravity is crucial for the design of packed bed chemical or biological reactors to be used for water reclamation and other life support processes involving water purification. Motil, Brian J. and Nahra, Henry K. and Balakotaiah, Vemuri Glenn Research Center NASA/TM-2005-213806, E-15145, Rept-2005-01-3035
Author: P. A. Ramachandran
Publisher: Gordon & Breach Publishing Group
ISBN:
Category : Science
Languages : en
Pages : 448
Get Book Here
Book Description
Author: Volker Hessel
Publisher: John Wiley & Sons
ISBN: 3527606270
Category : Science
Languages : en
Pages : 681
Get Book Here
Book Description
Micro process engineering is approaching both academia and industry. With the provision of micro devices, systems and whole plants by commercial suppliers, one main barrier for using these units has been eliminated. This book focuses on processes and their plants rather than on devices: what is 'before', 'behind' and 'around' micro device fabrication - and gives a comprehensive and detailed overview on the micro-reactor plants and three topic-class applications which are mixing, fuel processing, and catalyst screening. Thus, the book reflects the current level of development from 'micro-reactor design' to 'micro-reactor process design'.
Author: Vivek V. Ranade
Publisher: Elsevier
ISBN: 0080931448
Category : Technology & Engineering
Languages : en
Pages : 285
Get Book Here
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: A. Tamir
Publisher: Elsevier
ISBN: 1483297551
Category : Technology & Engineering
Languages : en
Pages : 780
Get Book Here
Book Description
Impinging streams is a unique and multipurpose configuration of a two-phase suspension for intensifying transfer processes in heterogeneous systems, viz. gas-solid, gas-liquid, solid-liquid and liquid-liquid. The essence of the method lies in the collision which results from bringing two streams of a suspension flowing on the same axis in opposite directions. Following the impact of the streams, a relatively narrow zone is created, which offers excellent conditions for enhancing the heat and mass transfer between the phases in the suspension.The following processes are considered in the light of the method of impinging streams: drying of particles, solid-solid and gas-gas mixing, absorption and desorption of gases from liquids, combustion of gas and coal, calcination of phosphate, creation of emulsions, liquid-liquid extraction, dissolution of solids, ion exchange, dust collection and granulation as well as evaporative cooling of air. Additional aspects considered in the book are: power input in performing the above processes, heat and mass transfer coefficient and its correlation, mixing properties of impinging stream reactors, residence time of the particles in the reactors, scale-up of impinging-stream reactors with respect to pressure, drop, hold-up and mean residence time of the particles as well as the heat transfer.The aim of the book is to review the state-of-the-art in the field of impinging streams, to present results of theoretical and experimental research, and to stimulate research and industrial application of the method so that reactors employing impinging streams will become a common tool in chemical engineering and other disciplines of engineering. The major conclusion of this work is that almost any process in chemical engineering can be conducted by impinging streams, resulting in higher efficiency and less power input in comparison with conventional methods.
Author: Hugo de Lasa
Publisher: Springer Science & Business Media
ISBN: 9400944004
Category : Science
Languages : en
Pages : 839
Get Book Here
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.
