Download or read book Effects of Configurations of External Loop Airlift Contactor on Hydrodynamics and Gas liquid Mass Transfer written by and published by . This book was released on 2007 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various configurations of external loop airlift contactor (ELALC) were examined for their hydrodynamic and mass transfer behavior using tap water. These behaviors was manipulated by changing the length of connection tubes (L[subscript c]), height of riser and downcmoer (L[subscript h]) and other configurations while keeping the ratio between downcomer and riser cross sectional area constant at 0.269. The results showed that the change of configuration could have effects on: gas holdup, liquid velocity, and gas-liquid mass transfer. Increasing L[subscript c] and L[subscript h] seemed to pose the same effect on the airlift performance. For instance, an increase in L[subscript c] from 20 to 40 cm, and Lp[subscript h] from 100 to 140 cm, could increase liquid velocity at 11.3 and 7.2%, decreased overall gas holdup at 8.6 and 3.3% and decreased the overall volumetric mass transfer coefficient at 8.2 and 5.6%, respectively. The effect of configurations on ELALC was investigated. ELALCs with inclined connection tubes and with close downcomer were compared with regular ELALC in terms of hydrodynamic and gas-liquid mass transfer behaviors. The two configurations presented large agglomerate of gas bubbles on the top connection tubes which resulted in more gas holdups and less downcomer liquid velocity when compared with regular ELALC. The mathematical model was developed based on the mass conservation principals to predict the gas-liquid mass transfer in the ELALC. Basically ELALC was represented by a series of reactors, i.e. the riser, downcomer, top and bottom connection tubes were represented by the dispersion model, and the two gas separators represented by the stirred tank model. The simulation results were found to be reasonably accurate for all experimental conditions employed in this work.
Download or read book Hydrodynamics and Mass Transfer in Internal Loop Airlift Contactor with Annulus Sparger in Saline Water written by and published by . This book was released on 2006 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation of the effect of salinity on the performance of airlift contactor was achieved using the 17L internal loop airlift system with a column height of 1.2 m, and 0.137 m diameter, and a draft tube height of 1 m. The diameters of the draft tubes were altered to vary the ratio between downcomer and riser cross sectional areas (A[subscript d]/A[subscript r]) from 0.061-1.01. The aeration was supplied in the superficial gas velocity (U[subscript sg]) from 0.01-0.07 m/s and the salinity levels were altered from 0, 15, 30, and 45 ppt. The Sauter mean diameter of the bubble appeared to be smaller in saline water than in fresh water due to two main reasons. The first one was the presence of hydrophilic repulsive force which inhibited bubble coalescence, and the second was the high Laplace pressure which promoted the breakup of the bubbles. The range of pressure difference, [delta]P, acting on the bubble which was found to promote bubble coalescence was between 15-20 N/m[superscript 2]. In saline water, the bubble size decreased with superficial gas velocity, u[subscript sg], where a reduction from 6 to 1 mm was observed with an increase in U[subscript sg] from 0.02-0.07 m/s. This was caused by the collision of bubbles at high gas hold-up in the system at higher gas flow rate which occurred at [delta]P greater than 20 N/m[superscript 2] and consequently supported bubble break-up. Axial variation in bubble size was only observed at low u[subscript sg] (less than 0.04 m/s) where bubbles in the bottom section of the airlift was larger than those in the middle and top sections. This was because the conditions in the middle and top sections were turbulent and with high [delta]P (27-65 N/m[superscript 2]), bubble break-up occurred. The effect of downcomer to riser area ratio was quite important and the highest range of [delta]P (approx. 50-97 N/m[superscript 2]) was found at the smallest downcomer area configuration which led to bubble break-up conditions. The overall volumetric mass transfer coefficient appeared lower in the saline water than in the fresh water where the levels of k[subscript L]a could be ordered from high to low as 0 ppt > 30 ppt > 15 ppt > 45 ppt. The specific area was found to be high in the saline water systems, however, the mass transfer coefficient was much higher in the fresh water system than in the saline water. The mass transfer coefficient was controlled by both natural and forced convections which were related significantly to the diameter and slip velocity of the gas bubbles.
Download or read book Airlift Bioreactors written by M. Y. Chisti and published by Springer. This book was released on 1989-02-28 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mass Transfer and Hydrodynamics in Stirred Gas liquid liquid Contactors written by Antonius Harold Gerrit Cents and published by . This book was released on 2003 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrodynamic and Mass Transfer Characteristics of an Airlift Contactor written by Diaa el Din H. El Gabbani and published by . This book was released on 1977 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Sparger Position on Bubble Size Distribution and Gas liquid Mass Transfer in Internal Airlift Contactors written by and published by . This book was released on 2009 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: To investigate the influence of sparger position on the bubble size distribution in internal loop airlift contactors. To complete the examination, the effects of other main design/operating parameters, i.e. the ratio between cross-sectional areas of downcomer and riser (A[subscript d]/A[subscript r]) and the superficial gas velocity, were also considered. The aeration in the ALC was achieved via the PVC ring sparger. The number of holes in the sparger was fixed at 60. The air flow rate was controlled in a range of superficial gas velocity, u[subscript sg] , from 4 to 10 cm s[superscript -1] . The ratios between cross-sectional areas were varying from 1.4 to 0.9. The sparger position was varied by changing the position of annulus sparger (0, 6 and 12 cm above the bottom of the contactor). A photographic technique was used to measure the bubble size and its distribution. The results revealed that the Sauter mean diameter of bubble was the smallest when the sparger was located at base of the reactor, and became larger when the sparger was moved to higher positions. It should be noted that at the lowest position, the sparger position was lower than the draft tube, therefore the recirculating fluid from the downcomer pushed the new-born bubbles towards the wall of the reactor and bubble breakage was observed. In addition, bubble size was also controlled by other flow conditions in the system, especially the superficial gas velocity (u[subscript sg] ), where an increase in u[subscript sg] decreased the bubble size due to the induction of high turbulence which rendered the bubble breakup. The system operated with smaller riser area had a higher level of turbulence, thus, the average bubble size was found to be smaller than system with larger riser area. At the bottom section of the reactor, the Sauter mean bubble diameter appeared to be larger than those at the middle and top sections. In terms of gas-liquid mass transfer, the sparger at its lowest position provided the highest level of overall volumetric mass transfer coefficient in the system. The specific interfacial area at the lowest sparger position was also found to be higher that other positions which suggested that this specific interfacial area could have strong positive impact on the gas-liquid mass transfer.
Download or read book Hydrodynamics and Mass Transfer Studies in High Pressure Gas liquid and Gas liquid solid Fluidization written by Wai Man R. Lau and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Slurry bubble columns and gas-solid fluidized bed reactors are some of the most commonly used industrial processes. Considerable interests have been recognized in the field of physical, chemical, petrochemical, electrochemical, and biochemical operations (Fan, 1989). In these reactor systems, large axial dispersion of phases and high flow patterns can be achieved by the excellent macromixing characteristics. It also provides excellent heat and mass transfer without the aid of external mechanisms and relatively easy operation. Despite the advantages of operations, the transport behavior in these systems is very complex and a comprehensive knowledge of the hydrodynamics, heat and mass transfer and mixing are required for successful application of these systems. Some aspects of the fundamental characteristics of evaporative liquid jets in gas-liquid-solid flows are studied and some pertinent literature is reviewed. It is found that the injection of an evaporative liquid jet decreases the minimum fluidization velocity at a high pressure due to the additional gas flow generated from liquid evaporation. Fluidizing gas velocities have no significant effect on the jet penetration length in a dense phase fluidized bed while it reduces the radial dispersed distance of the evaporative liquid. The tomographic images of liquid nitrogen injection in a dense phase fluidized bed indicate a distribution of reduced bubble sizes compared to a dry bed. The hydrodynamics, gas-liquid mass transfer properties and liquid entrainment phenomena in a high pressure and high temperature bubble column is investigated. Effects of pressure on hydrodynamics and mass transfer properties are mainly through the change in gas and liquid physical properties, which in turn changes the bubble dynamics that govern the transport phenomena. Experimental results show that liquid velocities have a direct influence on kl while other factors have a dominant effect on the interfacial area over kl. Liquid entrainment in bubble columns is controlled by the droplet formation during bubble bursting at interface. Effect of pressure on liquid entrainment is to due to the higher drag force exerted on the liquid droplet with higher gas density and the formation of smaller droplet by the smaller bubbles at high pressure.
Download or read book Chemical Engineering Abstracts written by and published by . This book was released on 1985 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design of Multiphase Reactors written by Vishwas G. Pangarkar and published by John Wiley & Sons. This book was released on 2015-01-27 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: Details simple design methods for multiphase reactors in the chemical process industries Includes basic aspects of transport in multiphase reactors and the importance of relatively reliable and simple procedures for predicting mass transfer parameters Details of design and scale up aspects of several important types of multiphase reactors Examples illustrated through design methodologies presenting different reactors for reactions that are industrially important Includes simple spreadsheet packages rather than complex algorithms / programs or computational aid
Download or read book Bubbly Flows written by Martin Sommerfeld and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book summarises the outcom of a priority research programme: 'Analysis, Modelling and Computation of Multiphase Flows'. The results of 24 individual research projects are presented. The main objective of the research programme was to provide a better understanding of the physical basis for multiphase gas-liquid flows as they are found in numerous chemical and biochemical reactors. The research comprises steady and unsteady multiphase flows in three frequently found reactor configurations, namely bubble columns without interiors, airlift loop reactors, and aerated stirred vessels. For this purpose new and improved measurement techniques were developed. From the resulting knowledge and data, new and refined models for describing the underlying physical processes were developed, which were used for the establishment and improvement of analytic as well as numerical methods for predicting multiphase reactors. Thereby, the development, lay-out and scale-up of such processes should be possible on a more reliable basis.
Download or read book Biofilms in Wastewater Treatment written by Stefan Wuertz and published by IWA Publishing. This book was released on 2003-04-30 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: The central theme of the book is the flow of information from experimental approaches in biofilm research to simulation and modeling of complex wastewater systems. Probably the greatest challenge in wastewater research lies in using the methods and the results obtained in one scientific discipline to design intelligent experiments in other disciplines, and eventually to improve the knowledge base the practitioner needs to run wastewater treatment plants. The purpose of Biofilms in Wastewater Treatment is to provide engineers with the knowledge needed to apply the new insights gained by researchers. The authors provide an authoritative insight into the function of biofilms on a technical and on a lab-scale, cover some of the exciting new basic microbiological and wastewater engineering research involving molecular biology techniques and microscopy, and discuss recent attempts to predict the development of biofilms. This book is divided into 3 sections: Modeling and Simulation; Architecture, Population Structure and Function; and From Fundamentals to Practical Application, which all start with a scientific question. Individual chapters attempt to answer the question and present different angles of looking at problems. In addition there is an extensive glossary to familiarize the non-expert with unfamiliar terminology used by microbiologists and computational scientists. The colour plate section of this book can be downloaded by clicking here. (PDF Format 1 MB)
Download or read book 11th International Symposium on Process Systems Engineering PSE2012 written by Iftekhar A Karimi and published by Elsevier. This book was released on 2012-09-09 with total page 1804 pages. Available in PDF, EPUB and Kindle. Book excerpt: While the PSE community continues its focus on understanding, synthesizing, modeling, designing, simulating, analyzing, diagnosing, operating, controlling, managing, and optimizing a host of chemical and related industries using the systems approach, the boundaries of PSE research have expanded considerably over the years. While early PSE research was largely concerned with individual units and plants, the current research spans wide ranges of scales in size (molecules to processing units to plants to global multinational enterprises to global supply chain networks; biological cells to ecological webs) and time (instantaneous molecular interactions to months of plant operation to years of strategic planning). The changes and challenges brought about by increasing globalization and the the common global issues of energy, sustainability, and environment provide the motivation for the theme of PSE2012: Process Systems Engineering and Decision Support for the Flat World. Each theme includes an invited chapter based on the plenary presentation by an eminent academic or industrial researcher Reports on the state-of-the-art advances in the various fields of process systems engineering Addresses common global problems and the research being done to solve them
Download or read book Numerical Simulation of Multiphase Reactors with Continuous Liquid written by Chao Yang and published by Academic Press. This book was released on 2014-06-13 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical simulation of multiphase reactors with continuous liquid phase provides current research and findings in multiphase problems, which will assist researchers and engineers to advance this field. This is an ideal reference book for readers who are interested in design and scale-up of multiphase reactors and crystallizers, and using mathematical model and numerical simulation as tools. Yang and Mao's book focuses on modeling and numerical applications directly in the chemical, petrochemical, and hydrometallurgical industries, rather than theories of multiphase flow. The content will help you to solve reacting flow problems and/or system design/optimization problems. The fundamentals and principles of flow and mass transfer in multiphase reactors with continuous liquid phase are covered, which will aid the reader's understanding of multiphase reaction engineering. Provides practical applications for using multiphase stirred tanks, reactors, and microreactors, with detailed explanation of investigation methods. Presents the most recent research efforts in this highly active field on multiphase reactors and crystallizers. Covers mathematical models, numerical methods and experimental techniques for multiphase flow and mass transfer in reactors and crystallizers.
Download or read book Gas Liquid Solid Fluidization Engineering written by Liang-Shih Fan and published by Butterworth-Heinemann. This book was released on 2013-10-22 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive mechanistic interpretation of the transport phenomena involved in various basic modes of gas-liquid-solid fluidization. These modes include, for example, those for three-phase fluidized beds, slurry columns, turbulent contact absorbers, and three-phase fluidized beds, slurry columns, turbulent contact absorbers, and three-phase transport. It summarizes the empirical correlations useful for predicting transport properties for each mode of of operation.Gas-Liquid-Solid Fluidization Engineering provides a comprehensive account of the state-of-the-art applications of the three-phase fluidization systems that are important in both small-and large-scale operations. These applications include fermentation,biological wastewater treatment, flue gas desulfurization and particulates removal, and resid hydrotreating. This book highlights the industrial implications of these applications. In addition, it discusses information gaps and future directions forresearch in this field.
Download or read book Innovative Wastewater Treatment Resource Recovery Technologies Impacts on Energy Economy and Environment written by Juan M. Lema and published by IWA Publishing. This book was released on 2017-06-15 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the 3R concept applied to wastewater treatment and resource recovery under a double perspective. Firstly, it deals with innovative technologies leading to: Reducing energy requirements, space and impacts; Reusing water and sludge of sufficient quality; and Recovering resources such as energy, nutrients, metals and chemicals, including biopolymers. Besides targeting effective C,N&P removal, other issues such as organic micropollutants, gases and odours emissions are considered. Most of the technologies analysed have been tested at pilot- or at full-scale. Tools and methods for their Economic, Environmental, Legal and Social impact assessment are described. The 3R concept is also applied to Innovative Processes design, considering different levels of innovation: Retrofitting, where novel units are included in more conventional processes; Re-Thinking, which implies a substantial flowsheet modification; and Re-Imagining, with completely new conceptions. Tools are presented for Modelling, Optimising and Selecting the most suitable plant layout for each particular scenario from a holistic technical, economic and environmental point of view.
Download or read book Bioprocess Engineering Principles written by Pauline M. Doran and published by Elsevier. This book was released on 1995-04-03 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emergence and refinement of techniques in molecular biology has changed our perceptions of medicine, agriculture and environmental management. Scientific breakthroughs in gene expression, protein engineering and cell fusion are being translated by a strengthening biotechnology industry into revolutionary new products and services. Many a student has been enticed by the promise of biotechnology and the excitement of being near the cutting edge of scientific advancement. However, graduates trained in molecular biology and cell manipulation soon realise that these techniques are only part of the picture. Reaping the full benefits of biotechnology requires manufacturing capability involving the large-scale processing of biological material. Increasingly, biotechnologists are being employed by companies to work in co-operation with chemical engineers to achieve pragmatic commercial goals. For many years aspects of biochemistry and molecular genetics have been included in chemical engineering curricula, yet there has been little attempt until recently to teach aspects of engineering applicable to process design to biotechnologists.This textbook is the first to present the principles of bioprocess engineering in a way that is accessible to biological scientists. Other texts on bioprocess engineering currently available assume that the reader already has engineering training. On the other hand, chemical engineering textbooks do not consider examples from bioprocessing, and are written almost exclusively with the petroleum and chemical industries in mind. This publication explains process analysis from an engineering point of view, but refers exclusively to the treatment of biological systems. Over 170 problems and worked examples encompass a wide range of applications, including recombinant cells, plant and animal cell cultures, immobilised catalysts as well as traditional fermentation systems.* * First book to present the principles of bioprocess engineering in a way that is accessible to biological scientists* Explains process analysis from an engineering point of view, but uses worked examples relating to biological systems* Comprehensive, single-authored* 170 problems and worked examples encompass a wide range of applications, involving recombinant plant and animal cell cultures, immobilized catalysts, and traditional fermentation systems* 13 chapters, organized according to engineering sub-disciplines, are groupled in four sections - Introduction, Material and Energy Balances, Physical Processes, and Reactions and Reactors* Each chapter includes a set of problems and exercises for the student, key references, and a list of suggestions for further reading* Includes useful appendices, detailing conversion factors, physical and chemical property data, steam tables, mathematical rules, and a list of symbols used* Suitable for course adoption - follows closely curricula used on most bioprocessing and process biotechnology courses at senior undergraduate and graduate levels.
Download or read book Innovative and Integrated Technologies for the Treatment of Industrial Wastewater written by Antonio Lopez and published by IWA Publishing. This book was released on 2011-12-15 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Innovative and Integrated Technologies for the Treatment of Industrial Wastewater deals with advanced technological solutions for the treatment of industrial wastewater such as aerobic granular biomass based systems, advanced oxidation processes integrated with biological treatments, membrane contactors and membrane chemical reactors. Wastewater from pharmaceutical, chemical and food industries as well as landfill leachates are specifically considered as representative of major problems encountered when treating industrial streams. The economic and environmental sustainability of the above solutions are also reported in the book and compared with the alternatives currently available in the market by life cycle assessment (LCA) and life cycle costing (LCC) methodologies. The implementation of the considered solutions at large scale could support and enhance the competitiveness of different industrial sectors, including the water technology sector, in the global market. Innovative and Integrated Technologies for the Treatment of Industrial Wastewater also makes a contribution towards defining: new concepts, processes and technologies in wastewater treatment with potential benefits for the stable quality of effluents, energy and operational costs saving, and the protection of the environment new sets of advanced standards for wastewater treatment new methodologies for the definition of wastewater treatment needs and framework conditions new information supporting development and implementation of water legislation.
