Effect of Inlet Diameter on the Performance of a Filtering Hydrocyclone Separator

Abstract

Hydrocyclones are separators used in several industry fields, such as mining, food and petrochemical. Our research group designed a new hydrocyclone, in which a conical filtering wall replaces the conical section, producing another liquid stream leaving the equipment, besides underflow and overflow streams. In the present work, the influence of inlet diameter (Di) of a filtering hydrocyclone was analyzed by an experimental and CFD study. Data from conventional hydrocyclones of the same configurations were also obtained. Under the same operating conditions and geometry, the filtering hydrocyclone presented a better performance than the conventional device. Under the experimental conditions evaluated, an increase in inlet diameter by a factor of 2.2 reduces the Euler number by 84%. Keywords: Hydrocyclones, solid-liquid separation, unit operations IntroductionHydrocyclones are very simple devices, that consist of a conical section, open at its apex (underflow), joined to a cylindrical section, which has a tangential feed inlet [1]. The top of the cylindrical section is closed with a plate with an axially mounted overflow pipe. Despite the apparent simplicity, hydrocyclones are very efficient to promote solid-liquid and liquid-liquid separations. These devices convert pressure generated by a centrifugal pump into centrifugal force, causing suspended solids in the mud to be separated from the fluid. This separation is actually accelerated settling due to the increased gravitational force cause by the centrifugal action inside the cone. The action inside the hydrocyclone can multiply gravitational force by as much as 200 times [2].Application of hydrocyclone for particles separation is widespread due to advantages such as low cost, simple structure, large capacity and low volume [3]. Despite its simplicity, the flow behavior in a hydrocyclone is quite complex. The internal flow in these devices is totally turbulent and presents high vorticity preservation, vortex breakdown, flow inversion, air core etc. However, advances in computational technology, over recent years, have led to models based on fundamental fluid flow to predict the performance of the equipment. Computational Fluid Dynamics (CFD) is an important www.cet-journal.com Page 2 Chemical Engineering & TechnologyThis article is protected by copyright. All rights reserved.technique to study the fluid dynamics of many physical systems and it has been used widely in several engineering applications [4,5], including modelling flow in hydrocyclones [6][7][8][9][10][11][12][13][14][15].The literature presents some classic designs of hydrocyclones (also called families), in which the main design variable is the cylindrical diameter (Dc), and the other geometric dimensions are related to this one. The use of a certain family of hydrocyclones is generally restricted to the demand for a specific application [16].For improving the performance of hydrocyclones, many modifications in the conventional configurations of this device have been proposed in the literatur...

Research on Structure Design of Dynamic Hydrocyclone on Board Ship

“…The larger rotating bowl diameter D is, the greater tangential velocity is, the bigger centrifugal force of separation is, and will be beneficial to oil-water separation; The longer bowl length L is, the greater the oil-water resides in the bowl is, the separation effect will be better. So, the length of the rotating bowl should be long enough in order to ensure the liquid resides in the bowl [4], [5], [6]. Normally reside time should be in 3 ~ 10 s. D and L of the rotary bowl affect the capacity of dynamic hydrocyclone, the greater the capacity is, the longer of the separation time should be.…”

Numerical Simulation of Flow Field Characteristics and Separation Performance Test of Multi-Product Hydrocyclone

“…Both experimental and theoretical studies by domestic and foreign scholars have generated a series of landmark research results in terms of research methods and content. In terms of the optimization of the structural parameters of the hydrocyclone, the representative studies include experimental studies on the hydrocyclone column height and diameter [14,15], feed inlet type and size [16,17], overflow pipe diameter, length, and shape, overflow pipe thickness [18][19][20], underflow outlet diameter, and shape, ratio relationship between the underflow outlet and overflow outlet [21][22][23]. A series of new hydrocyclone types have been designed, such as the built-in structural hydrocyclone [24,25], underflow outlet filled with flushing water [26], multi-stage series or parallel hydrocyclone [27][28][29], and three-product cyclone [30,31].…”

Effect of feed body geometry on separation performance of hydrocyclone

“…Delgadillo [14] explored alternative geometries of the cylinder using Computational Fluid Dynamics (CFD) modelling and observed great improvement during the classification of coarse particles, although there was a small increase in the by-pass of the very fine sizes. Also, some studies [15][16][17] paid attention to the influence on classification induced by inlet configuration and diameter.…”