Search results for " Njs"

showing 3 items of 3 documents

Measurements of Njs and Power Requirements in Unbaffled Bioslurry Reactors

2012

The remediation of urban/industrial polluted lands is a topic of crucial importance nowadays. Bioremediation techniques are widely employed to remove organic pollutants from contaminated soils because of their simplicity and cheapness. The bioslurry reactors mechanically agitated by stirrers represent one of the most promising bioremediation techniques. In the present work an unbaffled stirred vessel filled with solids and water is experimentally investigated from a fluid dynamic point of view. Air presence within the tank is guaranteed by the central vortex formation (typical occurrence concerning stirred vessels unprovided with baffles) instead of an intrinsically more expensive insufflat…

Settore ING-IND/26 - Teoria Dello Sviluppo Dei Processi Chimicilcsh:Computer engineering. Computer hardwareSettore ING-IND/25 - Impianti Chimicilcsh:TP155-156lcsh:TK7885-7895Mixing Solid-liquid suspension Njs Unbaffled Stirred tanks Bioslurry reactorslcsh:Chemical engineering
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Solid–Liquid Suspensions in Top-Covered Unbaffled Vessels: Influence of Particle Size, Liquid Viscosity, Impeller Size, and Clearance

2014

Particle suspension in liquids is a unit operation commonly encountered in the process industry. Although it is usually carried out in baffled stirred tanks, there are some specific applications where the presence of baffles may be undesirable. In the present work solid-liquid suspensions are investigated in a radially stirred unbaffled tank provided with a top cover. The minimum impeller speed at which all solid particles get suspended (Njs) and the relevant power requirements (Pjs) are assessed. The dependence of these two parameters on physical properties (liquid viscosity, particle concentration, and size) and system geometrical configurations (impeller diameter and clearance) is invest…

Work (thermodynamics)Settore ING-IND/26 - Teoria Dello Sviluppo Dei Processi ChimiciMaterials scienceChromatographyGeneral Chemical EngineeringSettore ING-IND/25 - Impianti ChimiciLiquid viscosityBaffleGeneral ChemistryMechanicsUnit operationSOLID-LIQUID SUSPENSIONIndustrial and Manufacturing EngineeringImpellerSOLID-LIQUID MIXINGParticlesolid liquid suspension stirred tank Njs unbaffled vessel complete suspension power requirementsParticle sizeUNBAFFLED STIRRED VESSELSSolid liquid
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SOLID-LIQUID SUSPENSIONS IN UNBAFFLED TANKS

2009

Unbaffled stirred tanks are seldom employed in the process industry as they are considered poorer mixers than baffled tanks. However, they might provide significant advantages in a wide range of applications like crystallization processes as well as for food and pharmaceutical industries, where the presence of baffles is often undesirable. In the present work solid-liquid suspension in an unbaffled stirred tank was investigated. A novel experimental method (steady cone radius method) was devised to ease the evaluation of the minimum impeller speed for complete particle suspension (Njs). Experiments encompassed a quite wide range of particle sizes, densities and solids concentration. The Njs…

unbaffled tanks solid-liquid systems particle suspension Njs
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