Energy effectiveness and working characteristics of different tower reactors for aerated slurry systems

1987 ◽  
Vol 52 (11) ◽  
pp. 2624-2639 ◽  
Author(s):  
Serafim D. Vlaev ◽  
Jindřich Zahradník
Keyword(s):  
Mass Transfer ◽  
Solid Phase ◽  
Bubble Column ◽  
Design Parameters ◽  
Achievable Rate ◽  
Energetic Efficiency ◽  
Rotating Disc ◽  
Energy Effectiveness ◽  
Wide Range ◽  
Reaction Processes

Decisive hydrodynamic and mass transfer characteristics of different types of tower reactors (rotating disc reactor, single and multistage sieve-tray bubble columns, tower reactor with ejector gas distributor) as well as the energy effectiveness of their performance were compared with the purpose to establish a quantitative basis for the qualified choice of the proper reactor type according to demands of specific reaction processes. Selected design parameters included gas and solid phase holdup, kLaL, liquid phase residence time distribution, and axial distribution of the solid phase, the experiments were carried out in a wide range of solid phase concentration (0-20 wt. %) and particle sizes (2.3-280 μm). The experimental results proved that due to their favourable suspension characteristics and operation stability the rotating disc reactors can be advantageously used for slow reaction processes with low demands on the intensity of interfacial gas-liquid contact which can be carried out at low gas flow rates. On the other hand the multistage bubble column reactors proved to be superior devices for transport–controlled reaction processes regarding both the achievable rate of interfacial mass transfer and the overall energetic efficiency of phase contacting.

scholarly journals Demonstration of Mass Transfer Using Aeration of Water

1970 ◽  
pp. 56-60
Author(s):  
Sultana R Syeda ◽  
BMS Arifin ◽  
Md M Islam ◽  
Anup Kumar
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Dimensional Analysis ◽  
Engineering Students ◽  
Chemical Engineering ◽  
Bubble Column ◽  
Mass Transfer Process ◽  
Design Parameters ◽  
Sieve Tray

An experiment was developed using aeration of water for demonstrating the phenomenon of mass transfer. The demonstration was designed to provide both conceptual and practical insight of the mass transfer process. A bubble column fitted with a sieve tray was used to carry out the experiment. The air flow rate and hole size of the sieve tray were varied. Mass transfer coefficient was obtained from the initial and final oxygen concentrations of the aerated water. A dimensionless correlation for mass transfer coefficient in terms of the experimental variables was developed by dimensional analysis and regression of the experimental data. The demonstration is suitable for chemical and other engineering students and can be fit in one laboratory session of three hours. The experimental setup is simple and inexpensive, and can be developed in-house. In addition to the laboratory demonstration, the experiment can also be used for optimizing design parameters of industrial aeration tanks. Keywords mass transfer coefficient; aeration; bubble column; dimensional analysis; Stanton number. DOI: 10.3329/jce.v25i0.7239Journal of Chemical Engineering, IEB Vol. ChE. 25, No. 1, December 2010 pp.56-60

A Controlled Composition Study of Calcium Carbonate Crystal Growth: The Influence of Scale Inhibitors

CORROSION ◽  
1981 ◽  
Vol 37 (2) ◽  
pp. 76-81 ◽  
Author(s):  
George H. Nancollas ◽  
Thomas F. Kazmierczak ◽  
Eric Schuttringer
Keyword(s):  
Crystal Growth ◽  
Calcium Carbonate ◽  
Solid Phase ◽  
Ionic Species ◽  
Constant Composition ◽  
Rotating Disc ◽  
Active Growth ◽  
Ambient Temperatures ◽  
Composition Method ◽  
Wide Range

Abstract The precipitation of calcium carbonate is of considerable importance in a wide variety of scale forming situations since carbonate concentrations in the environment are usually quite appreciable. As a first-formed solid phase, calcium carbonate may induce the growth of other scale minerals on its surface. Since the solubility of calcium carbonate polymorphs decreases with increasing temperature, the problem is also aggravated by the relatively high ambient temperatures in many processes. This paper describes a new highly reproducible, seeded crystal growth method in which the activity of ion species is automatically maintained constant during the crystal growth reaction so that the kinetics can be studied over a wide range of supersaturation. The rate of calcite growth, over a 30X range of ionic strength, is proportional to the square of the relative supersaturation ([{Ca2+}{CO32−}]1/2−Kso1/2)2 expressed in terms of the activities of the ionic species. The rate is directly proportional to the seed concentration over a 3X range of the latter. The constant composition method has also been used to investigate the mineralization rate of a rotating disc of calcite (∼ 1 cm2 area) having very well defined hydrodynamic parameters. The rate of reaction (per m seed surface) is in striking agreement with that obtained using seed crystals (typically 500 cm2) despite the large difference in available growth sites. The evidence points to a surface controlled crystallization mechanism. Traces of orthophosphate and typical phosphonate scale inhibitors markedly inhibit the rate of calcium carbonate scale formation. Even with the sustained driving force provided by the constant composition method, a concentration of 9.1×10−8 M hydroxyethylidene-1, 1-diphosphonic acid completely inhibits the crystallization of calcite for more than 100 hours. The effectiveness of this scale inhibitor is clearly due to adsorption at active growth sites on the developing crystal surfaces.

Monte Carlo calculation of the energy parameters and spatial distribution of the cathodic arc ions while passing through the macro-particles filters

2018 ◽  
Vol 1 (1) ◽  
pp. 30-34 ◽  
Author(s):  
Alexey Chernogor ◽  
Igor Blinkov ◽  
Alexey Volkhonskiy
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Monte Carlo ◽  
Monte Carlo Calculation ◽  
Inhomogeneous Magnetic Field ◽  
Flow Energy ◽  
Wide Range ◽  
Field Concentrator ◽  
Cathodic Arc ◽  
The Magnetic Field

The flow, energy distribution and concentrations profiles of Ti ions in cathodic arc are studied by test particle Monte Carlo simulations with considering the mass transfer through the macro-particles filters with inhomogeneous magnetic field. The loss of ions due to their deposition on filter walls was calculated as a function of electric current and number of turns in the coil. The magnetic field concentrator that arises in the bending region of the filters leads to increase the loss of the ions component of cathodic arc. The ions loss up to 80 % of their energy resulted by the paired elastic collisions which correspond to the experimental results. The ion fluxes arriving at the surface of the substrates during planetary rotating of them opposite the evaporators mounted to each other at an angle of 120° characterized by the wide range of mutual overlapping.

Analysis of Aromatic Amines in Industrial Wastewater by Capillary Gas Chromatography-Mass Spectrometry

2000 ◽  
Vol 35 (2) ◽  
pp. 245-262 ◽  
Author(s):  
Francis I. Onuska ◽  
Ken A. Terry ◽  
R. James Maguire
Keyword(s):  
Gas Chromatography ◽  
Aromatic Amines ◽  
Methylene Chloride ◽  
Solid Phase ◽  
Stationary Phases ◽  
Gas Chromatography Mass Spectrometry ◽  
Substituted Anilines ◽  
Environmental Media ◽  
Solid Phase Extraction Cartridge ◽  
Wide Range

Abstract The analysis of aromatic amines, particularly benzidines, at trace levels in environmental media has been difficult because of the lack of suitable deactivated capillary column stationary phases for gas chromatography. This report describes the use of an improved type of column as well as a method for the analysis of anilines and benzidines in water, wastewater and sewage samples. Extraction procedures are applicable to a wide range of compounds that are effectively partitioned from an aqueous matrix into methylene chloride, or onto a solid-phase extraction cartridge. The extracted analytes are also amenable to separation on a capillary gas chromatographic column and transferable to the mass spectrometer. These contaminants are converted to their N-trifluoroacetyl derivatives. Aniline and some substituted anilines, and 3,3’-dichlorobenzidine and benzidine were determined in 24-h composite industrial water, wastewater, primary sludge and final effluent samples at concentrations from 0.03 up to 2760 µg/L.

Recent Application of Polystyrene-supported Triphenylphosphine in Solid-Phase Organic Synthesis

2019 ◽  
Vol 23 (6) ◽  
pp. 643-678
Author(s):  
Lalthazuala Rokhum ◽  
Ghanashyam Bez
Keyword(s):  
Organic Synthesis ◽  
Combinatorial Chemistry ◽  
Solid Phase ◽  
Recent Application ◽  
Organic Transformations ◽  
Solid Phase Organic Synthesis ◽  
Wide Range ◽  
Fast Development ◽  
Polymer Supported

Recent years have witnessed a fast development of solid phase synthetic pathways, a variety of solid-supported reagent and its applications in diverse synthetic strategies and pharmaceutical applicability’s. Polymer-supported triphenylphosphine is getting a lot of applications owing to the speed and simplicity in the process. Furthermore, ease of recyclability and reuse of polymer-supported triphenylphosphine added its advantages. This review covers a wide range of useful organic transformations which are accomplished using cross-linked polystyrene-supported triphenylphosphine with the aim of giving renewed interest in the field of organic and medicinal-combinatorial chemistry.

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