Chemical Kinetics in Dispersed-Phase Reactors

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Ben J McCoy ◽  
Giridhar Madras
Keyword(s):  
Size Distribution ◽  
Chemical Reaction ◽  
Chemical Engineering ◽  
Numerical Solutions ◽  
Continuous Phase ◽  
Reaction Engineering ◽  
Dispersed Phase ◽  
Mass Balances ◽  
Distribution Dynamics ◽  
Phase Size

Many chemical engineering processes occur under conditions when a dispersed phase undergoes fragmentation (breakup) and/or aggregation (coalescence). It is of considerable interest to model a chemical process that occurs at the interface and therefore depends on the evolving size distribution of the dispersed phase. We apply distribution kinetics to represent the evolution of the dispersed-phase size distribution for simultaneous fragmentation and coalescence. The continuous phase with dissolved reactant enters and exits a continuous-flow stirred-tank reactor. When the dispersed phase contained within the vessel satisfies a similarity solution, several rate expressions, including one for interphase mass transfer, that depend on mass moments of the size distribution allow analytical or simple numerical solutions. The solutions demonstrate how chemical reaction mass balances can be combined with distribution dynamics to extend chemical reaction engineering analysis.

Effect of Shear and Water Cut on Phase Inversion and Droplet Size Distribution in Oil–Water Flow

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Mo Zhang ◽  
Ramin Dabirian ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Phase Inversion ◽  
Droplet Size Distribution ◽  
Continuous Phase ◽  
Dispersed Phase ◽  
Water Emulsion ◽  
Inversion Region ◽  
Oil Water ◽  
Water Cut

Oil–water dispersed flow occurs commonly in the petroleum industry during the production and transportation of crudes. Phase inversion occurs when the dispersed phase grows into the continuous phase and the continuous phase becomes the dispersed phase caused by changes in the composition, interfacial properties, and other factors. Production equipment, such as pumps and chokes, generates shear in oil–water mixture flow, which has a strong effect on phase inversion phenomena. The objective of this paper is to investigate the effects of shear intensity and water cut (WC) on the phase inversion region and also the droplet size distribution. A state-of-the-art closed-loop two phase (oil–water) flow facility including a multipass gear pump and a differential dielectric sensor (DDS) is used to identify the phase inversion region. Also, the facility utilizes an in-line droplet size analyzer (a high speed camera), to record real-time videos of oil–water emulsion to determine the droplet size distribution. The experimental data for phase inversion confirm that as shear intensity increases, the phase inversion occurs at relatively higher dispersed phase fractions. Also the data show that oil-in-water emulsion requires larger dispersed phase volumetric fraction for phase inversion as compared with that of water-in-oil emulsion under the same shear intensity conditions. Experiments for droplet size distribution confirm that larger droplets are obtained for the water continuous phase, and increasing the dispersed phase volume fraction leads to the creation of larger droplets.

Exploration of Chemical Reaction Effects on Entropy Generation in Heat and Mass Transfer of Magneto-Jeffery Liquid

2018 ◽  
Vol 16 (9) ◽  
Author(s):  
R. Mohapatra ◽  
B. Mahanthesh ◽  
B.J. Gireesha ◽  
S.R. Mishra
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Chemical Reaction ◽  
Chemical Engineering ◽  
Numerical Solutions ◽  
Ceramic Materials ◽  
Transverse Magnetic ◽  
Cross Diffusion ◽  
Order Chemical Reaction ◽  
First Order Chemical Reaction

AbstractIn many chemical engineering processes, a chemical reaction between a foreign mass and the fluid does occur. These processes find relevance in polymer production, oxidation of solid materials, ceramics or glassware manufacturing, tubular reactors, food processing, and synthesis of ceramic materials. Therefore, an exploration of homogeneous first-order chemical reaction effects on heat and mass transfer along with entropy analysis of Jeffrey liquid flow towards a stretched isothermal porous sheet is performed. Fluid is conducting electrically in the company of transverse magnetic field. Variations in heat and mass transfer mechanisms are accounted in the presence of viscous dissipation, heat source/sink and cross-diffusion aspects. The partial differential equations system governing the heat transfer of Jeffery liquid is reformed to the ordinary differential system through relevant transformations. Numerical solutions based on Runge-Kutta shooting method are obtained for the subsequent nonlinear problem. A parametric exploration is conducted to reveal the tendency of the solutions. The present study reveals that the Lorentz force due to magnetism can be used as a key parameter to control the flow fields. Entropy number is larger for higher values of Deborah and Brinkman numbers. It is also established that the concentration species field and its layer thickness of the Jeffery liquid decreases for a stronger chemical reaction aspect. To comprehend the legitimacy of numerical results a comparison with the existing results is made in this exploration and alleged an admirable agreement.

Modeling of the Dispersed-Phase Size Distribution in Bubble Columns

2002 ◽  
Vol 41 (10) ◽  
pp. 2560-2570 ◽  
Author(s):  
Lars Hagesaether ◽  
Hugo A. Jakobsen ◽  
Hallvard F. Svendsen
Keyword(s):  
Size Distribution ◽  
Bubble Columns ◽  
Dispersed Phase ◽  
Phase Size

Water Modeling Study on Dispersed Phase Size Distribution and Interface Areas in Metallurgical Multiphase Reactor

2014 ◽  
Vol 1052 ◽  
pp. 567-573
Author(s):  
Ren Chen ◽  
Yan Huang ◽  
Ling Ling Li ◽  
Zhi Guo Luo
Keyword(s):  
Size Distribution ◽  
Empirical Formula ◽  
Dispersed Phase ◽  
Water Modeling ◽  
Operation Conditions ◽  
Box Counting ◽  
Granularity Level ◽  
Phase Size ◽  
The Law ◽  
Modeling Study

The combined blowing process of metallurgical multiphase reactor was simulated by water modeling. The effects of operation conditions on dispersed phase size distribution were studied and an empirical formula was obtained. Based on the law of additive codimensions, the interface areas under different operation conditions were calculated by means of box counting and projection relationship. The results show that the frequency of dispersed phase with certain granularity level are in a certain proportion to its size level, and the dispersed phase areas are influenced by the top and bottom combined blowing.

Structural Changes in Alloy Anodes for Li-Ion Batteries

2018 ◽  
Author(s):  
Jacob N. Adams ◽  
Logan J. Ausderau ◽  
George J. Nelson
Keyword(s):  
Size Distribution ◽  
Structural Changes ◽  
Substantial Reduction ◽  
High Capacity ◽  
Continuous Phase ◽  
Microstructural Changes ◽  
Volumetric Expansion ◽  
Electrochemical Testing ◽  
Pristine Sample ◽  
Phase Size

Tin (Sn) alloy electrodes show great potential for advancing battery performance due to the high capacity of tin. To realize this potential, the volumetric expansion during the lithiation process must be mitigated. One means of mitigating volumetric expansion of tin is to alloy it with copper to create Cu6Sn5. Such alloy electrodes retain some of the high capacity of tin, while attempting to accommodate volumetric changes with the addition of the malleable copper. Lithiation and delithiation tests were conducted with the Cu6Sn5 pellet electrodes to produce microstructural changes at the electrode surface. To observe and quantify these microstructural changes, x-ray microtomography was performed on electrode samples after electrochemical testing. The microtomography data was reconstructed into a 3D image, segmented, and the continuous phase size distribution (PSD) of each electrode sample was analyzed. The electrodes lithiated to 0 V vs Li/Li+ and then delithiated to 0.2 V vs. Li/Li+ showed the most substantial reduction in overall PSD compared to the other samples. This suggests that full lithiation of the Sn present in the alloy electrodes followed by partial delithiation of the Li4.4Sn to Li2CuSn can cause substantial microstructural changes related to volume expansion on lithiation and structural collapse upon delithiation. The electrodes fully lithiated to 0 V vs Li/Li+ and not delithiated show a higher overall phase size distribution, including all solid phases, than the pristine sample and the electrode samples that were partially lithiated to 0.2 V vs. Li/Li+ and delithiated to 1.5 V vs. Li/Li+. The higher overall phase size distribution that is shown by the sample that was fully lithiated and not delithiated is evidence of the significant volumetric expansion of the Cu6Sn5 compound due to lithiation. During this process of volumetric expansion, the phase size distribution of the Cu6Sn5/Sn phase is shown to decrease. When the volumetric expansion of the lithiated electrode samples and the volumetric contraction of the delithiated electrode sample are considered together, it can be inferred that the microstructural changes that are observed, such as the decrease in phase size distribution of the Cu6Sn5/Sn phase, can be attributed to the volumetric expansion and contraction of the compound during the lithiation and delithiation process.

scholarly journals Corrigendum / Erratum / Retraction

2017 ◽  
Vol 12 (2) ◽  
pp. App.7
Author(s):  
Istadi Istadi
Keyword(s):  
Chemical Reaction ◽  
Scientific Community ◽  
Chemical Engineering ◽  
Reaction Engineering ◽  
State University ◽  
Scientific Publishing ◽  
Louisiana State University ◽  
Published Paper ◽  
Simultaneous Elimination ◽  
Chemical Reaction Engineering

RETRACTION TO:Dhal, G.C., Dey, S., Prasad, R., Mohan, D. (2017). Simultaneous Elimination of Soot and NOX through Silver-Barium Based Catalytic Materials. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (1): 71-80 (doi:10.9767/bcrec.12.1.647.71-80)This article has been retracted by Publisher based on the following reason:Letter to Editor from Prof. James J. Spivey (Department of Chemical Engineering, Louisiana State University) who reported that a comparison of this paper with a previously paper published in Catalysis Today (258 (2015) 405-415, doi:10.1016/j.cattod.2015.02.024) shows significant duplication according to analysis by iThenticate shows 73% similarity, which is far more than acceptable. The authors have plagiarized part of the paper that had already published in [Catalysis Today (258 (2015) 405-415, doi:10.1016/j.cattod.2015.02.024)]. Based on clarification via email, Authors of the above paper have admitted their plagiarism to the previously published paper by Catalysis Today.Editor of Bulletin of Chemical Reaction Engineering & Catalysis acknowledged Prof. James J. Spivey due to the valuable Letter to Editor.One of the conditions of submission of a paper for publication in this journal is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.  

Phase Inversion in Two-Phase Liquid Systems

1992 ◽  
Vol 57 (7) ◽  
pp. 1419-1423
Author(s):  
Jindřich Weiss
Keyword(s):  
Interfacial Tension ◽  
Phase Inversion ◽  
Continuous Phase ◽  
Considerable Effect ◽  
Weak Dependence ◽  
Dispersed Phase ◽  
Two Phase ◽  
Liquid Systems ◽  
Phase Liquid

New data on critical holdups of dispersed phase were measured at which the phase inversion took place. The systems studied differed in the ratio of phase viscosities and interfacial tension. A weak dependence was found of critical holdups on the impeller revolutions and on the material contactor; on the contrary, a considerable effect of viscosity was found out as far as the viscosity of continuous phase exceeded that of dispersed phase.

Sign in / Sign up

Export Citation Format

Share Document