2 edition of Mixing and mass transfer in bubble columns containing drag reducing additives. found in the catalog.
Mixing and mass transfer in bubble columns containing drag reducing additives.
MSc thesis, Chemical Engineering.
is the surfactant at the interface (e.g., the air bubble surrounded by water) with the polar or charge end in the water and the non polar end protruding into the bubble. The net effect is to reduce oxygen transfer in the area around the bubble by reducing molecular diffusion of oxygen. The time required for adsorption varies with the surfactant. 29 Axial Dispersion Model Analysis of Homogeneous-Heterogeneous Reactions in a Tubular Reactor P.A. Ramachandran, R.A. Mashelkar Letters in Heat and Mass Transfer, , 2, 30 A New Model for Hollow Fibre Enzyme Reactor R A. Mashelkar, P.A. . The mixing of liquids, solids and gases is one of the most common unit operations in the food industry. Mixing increases the homogeneity of a system by reducing non-uniformity or gradients in composition, properties or temperature. Secondary objectives of mixing include control of rates of heat and mass transfer, reactions and structural changes. In food processing applications, additional. L.S. Fan, Samir Kumar and K. Kusakabe, , "Heat Transfer in Bubble Columns and Three-Phase Fluidized Beds Under High Gas Holdup Conditions." AIChE Jour -
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The mixing properties of bubble columns are usually described by the axial dispersed plug flow model. In order to determine the dispersion coefficients of BC I and BC 11 the Mixing and mass transfer in tall bubble columns Er 0,25 0,20 0,15 0,10 f- 0,05 stationary methods was by: Hydrodynamics, Mixing, and Mass Transfer in Bubble Columns with Internals Mohamed Hamed Washington University in St.
Louis Follow this and additional works at: This Dissertation is brought to you for free and open access by Washington University Open Scholarship. It has been accepted for inclusion in AllCited by: The effects of aliphatic alcohols on mass transfer and drag coefficients of a carbon dioxide bubble were investigated in very dilute aqueous solutions.
A high speed photography technique provided an almost continuous record of the bubble volume, shape, and oscillation, as related to the height of the bubble in the liquid and the time elapsed Cited by: Mixing time measurements have been carried out in a m I.D.
short bubble column (Hc/D ⩽ 5) with different spargers and for different clear liquid height to diameter (HC/D) ratios.
The productivity of a bubble column reactor (BCR) critically depends upon gas-liquid mass transfer coefficient, k L prediction of k L a as function of design and operating conditions is central to BCR scale up.
A large number of researchers have successfully characterized k L a experimentally in terms of superficial gas velocity, U sg using the power law relation k L a = α U sg β, Cited by: 3. Determination of gas-liquid mass transfer coefficient in a bubble column by an eigenvalue method.
Chemical Engineering Science43 (4), DOI: /(88) M. Moo-Young, Y. Kawase. Gas hold-up and mass transfer in a bubble column with viscoelastic fluids. Bubble motion and mass transfer in non‐Newtonian fluids: Part I. Single bubble in power law and Bingham fluids mass transfer and drag are found to increase with increase in the Bingham number N B El-Temtamy, S.
Khalil, A. Nour-El-Din and A. Gaber, Oxygen mass transfer in a bubble column bioreactor containing lysed yeast. Huahai Zhang, Kunyu Guo, Yuelin Wang, Ali Sayyar, Tiefeng Wang, Numerical simulations of the effect of liquid viscosity on gas-liquid mass transfer of a bubble column with a CFD-PBM coupled model, International Journal of Heat and Mass Transfer, /masstransfer,(), ().
Volumetric mass transfer coefficients (K L a) were measured. In water the introduction of the draft tube increased the K L a coefficient. The increase in K L a became larger with impeller speed.
On the other hand, mass transfer in dilute polymer solutions decreased due to the presence of the draft tube. However, most mass transfer systems contain moving fluid so that mass transfer by molecular motion is supplemented by convective transfer. There is an enormous variety of circumstances in which convective mass transfer takes Mixing and mass transfer in bubble columns containing drag reducing additives.
book. In this chapter, we will con-sider the theory of mass transfer with applications relevant to bioprocessing. Dispersion in bubble column reactors Rising bubbles promote liquid-phase hydrodynamic dispersion and influence mixing of the phases and mass transfer rates.
To date, most analyses have characterized liquid dispersion in bubble columns via a single Peclet number, though dispersion varies axially in bubble columns (Bischoff and Phillips ). Fig. exhibits an example plot of ln C o C vs.
t at a diverse N 2 superficial velocities, using a solution composition of M K 2 Cr 2 O 7 + M H 2 SO 4 and 50 ppm surfactant concentration with employing 5 actively exposed copper tube bundles.
The coefficient of mass transfer of chromates in the solution was determined in different and multiple conditions by calculating the.
The low mixing intensity in the bubble column was increased by an order of magnitude in the airlift reactors. Effect of Drag Reducing additives on Mass Transfer Characteristics in Gas–Liquid. Bubble columns and slurry bubble columns are considered reactors of choice for a wide range of applications in the chemical, biochemical, and petrochemical industries.
Most of the chemical applications of bubble columns include exothermic processes and hence they require some means of heat removal to maintain a steady process. The most practical means for heat removal in these reactors is the.
The influence of polymer additives upon the gas‐liquid mass transfer in stirred tanks is examined. While the addition of sodium carboxymethyl‐cellulose brings about a reduction of the overall liquid side mass transport coefficient which is in line with the predictions by earlier works, the reduction of k L a in polyacrylamide solutions of equal viscosity is much stronger.
phase gas–liquid ﬂow are the drag force, lift force and “Mixing and Mass Transfer. in Tall Bubble Columns DL, of a 14cm diameter and 98cm tall bubble column were studied. The mass. Mass transfer in bubble column with and without internals.
Multiphase reactions are backbone of chemical industry. They are frequently encountered in many petrochemical processes, biochemical processes, waste water treatment, and in production of various organic compounds. Fischer Tropsch (FT) synthesis is one of such complex widely used.
With cocurrent flow and a highly baffled column, the reactor has mass transfer characteristics similar to those of a static mixer. The reactor may sometimes contain a solid suspended in the liquid phase. IV.C.2 Classification. The bubble column is a typical gas–liquid heterogeneous reactor with the design also applicable to liquid–liquid.
the concentration field surrounding a single bubble in a bubble swarm has a crucial influence on the overall mass transfer in the reactor. Especially in case of mixing sensitive reactions in a chemical reaction networks with fast reactions the locally resolved concentration field is of special interest.
Mixing time in the presence of drag reducing agents was also the range of variables covered in this work mixing time in mechanically agitated contactors and bubble columns was.
mass transport in bubble columns and to provide reliable data of volumetric mass transfer coefﬁcient. Keywords: bubble column; mass transfer; dynamic pressure method 1.
Introduction Bubble columns are multiphase reactors/contactors which are widely used in chemical and biochemical industry [1–4]. In this study, the oxygen transfer rate (OTR), bubble size distribution, interfacial area per unit volume and liquid film mass transfer coefficient have all been measured in a m diameter pilot-scale bubble column operated at industrially relevant superficial velocities between and m s −1 for which few data exist in the literature.
• Large Bubble Mixing system installed in five cells in Train 10 • Existing HP submersible mechanical mixers with controls •Large Bubble Mixing system consisted of an HP rotary screw compressor, floor-mounted nozzles, piping, and controls. This work investigates the impact of fluid (CO2(g), water) flow rates, channel geometry, and the presence of a surfactant (ethanol) on the resulting gas–liquid flow regime (bubble, slug, annular), pressure drop, and interphase mass transfer coefficient (kla) in the FlowPlateTM LL (liquid-liquid) microreactor, which was originally designed for immiscible liquid systems.
Studies like fractional holdup, mixing time and mass transfer characteristics are needed (Ali Abdul R. Jasim, ). Many works on bubble column for holdup, mixing time and mass transfer characteristics have been reported in the literature (Shah et al., ; Pandit and Jo shi, ; Thorat et al., ; Mashelkar, ; Deckwer.
Key Words: Bioprocess Engineering, Bioreactors, Bubble Columns, Airlift-Loop-Reactors, Gas-Liquid Fluid Flow, Biochemical Reactions, Mixing, Mass Transfer, Heat Transfer Contents 1. Introduction 2. First characterization of bubble columns 3.
Mass transfer 4. Oxygen Transfer Efficiency 5. Examples of bubble column reactors 6. Airlift Loop. In bubble columns and air-lift reactors, similarly to the mass transfer, mixing is controlled via the flow rate (superficial aeration) and the rheological properties of the fluid.
Through a Bubble Column. Abd Ali, K. M.*. Abstract - In this investigation, CFD simulation is presented to study the hydrodynamic of bubbly flow and mass transfer in bubble column using Eulerian- Eulerian Multifluid approach with a standard k-ε turbulence model.
unsteady state method for modeling the. In both systems the knowledge of mass transfer rates from the liquid to the packing is important for the design of equipment. In the present investigation, the fluid dynamic behavior of a simple bubble column and a bubble column containing small size particles.
Peter Lobaccaro, Meenesh R. Singh, Ezra Lee Clark, Youngkook Kwon, Alexis T. Bell, Joel W. Ager, Effects of temperature and gas–liquid mass transfer on the operation of small electrochemical cells for the quantitative evaluation of CO 2 reduction electrocatalysts, Physical Chemistry Chemical Physics, /C6CPH, 18, 38, ( 1.
Introduction Bubble columns are extensively used as gas-liquid contactors in the chemical, petrochemical and biochemical industries. Effective phase mixing leading to improve heat and mass transfer characteristics and other various advantages of bubble column reactors render it an attractive choice of reactors for different chemical and bio-chemical processes.
By measuring the time at the maximum of residence time distribution in the multistage slurry bubble column and by using the relationships between gas holdup (ε G = approx. ), volumetric mass transfer coefficient, and the mean superficial gas velocity (ū G = approx.
cm/s) in a standard slurry bubble column, the concentration. Mixing, Bubble Column, Entropy, Two-Phase Flow. Introduction. Bubble columns are extensively used as gas-liquid contactors in the chemical, petrochemical and biochemical industries. Effective phase mixing leading to improve heat and mass transfer characteristics and other various advantages of bubble col umn reactors render it an attractive.
The independence of heat flux and effectiveness from liquid depth supports the assumption of negligible gas-side resistance to heat and mass transfer.
Despite the mass exchange, the bubble column dehumidifier performs like a typical heat exchanger: the heat flux decreases and effectiveness increases with increasing coil area.
Effects of Multiple Draft Tubes with Perforated Plates on Average Gas Holdup, Volumetric Mass Transfer Coefficient and Liquid Mixing Time in a Bubble Column. KAGAKU KOGAKU RONBUNSHU.
describe bubble column reactors. Some aspects to take into account when it is proposed a model are the mathematical nature of the equations and the degree of complex of their solution (Deckwer, ).
The liquid phase mixing has an important effect on mass transfer capabilities of bubble column. Mixing in bubble columns is due to liquid. Hydrodynamics and Mass Transfer in Bubble Columns by Onkar N.
Manjrekar A dissertation presented to the Graduate School of Arts & Sciences of Washington University in partial fulfillment of the requirements for the degree of Doctor of Philosophy May St.
Louis, Missouri. The mixing characteristics in bubble columns and airlift reactors are analyzed using computational fluid dynamics. In the simulations, an Eulerian-Eulerian approach was used to model air as the dispersed phase within a continuous phase of water using the commercial software FLUENT.
Scaling up of Fisher-Tropsh requires suitably accurate estimations of hydrodynamic and mass transfer parameters as a function of column size and slurry concentration. The present study focuses on gas holdup, volumetric mass. transfer and local mass transfer coefficients in a slurry bubble column employing a C.
9-C. Iraqi paraffin oil as a. Bubble column reactors belong to the general class of multiphase reactors which consist of three main categories namely, the trickle bed reactor (fixed or packed bed), fluidized bed reactor, and the bubble column reactor. Bubble columns are the devices in which gas, in.
Francisco J. Trujillo, Tomasz Safinski and Adesoji A. Adesina, Solid–liquid mass transfer analysis in a multi-phase tank reactor containing submerged coated inclined-plates: A computational fluid dynamics approach, Chemical Engineering Science, 64, 6, (), ().Gas hold‐up and volumetric mass transfer coefficient in bubble columns under foam control.
Satoshi Takesono. Graduate School of Science & Technology, Niigata University, Ikarashi 2, Niigata ZC ‐21, Japan. Search for more papers by this author. Masayuki Onodera. Mass transfer in the homogeneous flow regime of a bubble column.
Drag force of bubble swarms and numerical simulations of a bubble column with a CFD-PBM coupled model. CFD-based scale-up of hydrodynamics and mixing in bubble columns. Chemical Engineering Research and Design, DOI: /