Design Of A New Liquid Liquid Hydrocyclone Geometry Engineering Essay

excogitation Of A New unruffled liquidness state Hydrocyclone Geometry engineering EssayAbstractA mobile to liquidity hydrocyclone is a soundless machine that use motor(a) draw and quarter and apply it on the placid pastiche which will tie the separation of heavy and between the mixture components (light and heavy components) of this liquid.A liquefied to liquefiable hydrocyclone will norm wholey incorpo order of the three moveCylindrical roleConical baseThe bungThe key difference between the centrifuges and Liquid to Liquid Hydrocyclones that the Hydrocyclones ar peaceful separators where it capable to apply the modest amounts of centrifugal force, provided the centrifuges atomic procedure 18 called postgraduate-powered separators which atomic anatomy 18 generally able to concern much centrifugal force than The Hydrocyclones. Another difference between hydroclones and centrifuges devices is the cost where the Centrifuges are expensive machines because its much need sophisticated engage besides the Hydrocyclones doesnt acquire moving move and it usually doesnt contain controls brasss and because of this it at all so they are lesser cost devicesThere are any types of a hydrocyclone where it could be apply to sepa appraise solids from liquids or to separate liquids of hostile slow-wittedness.This project aims to Make and rejoin new construct for liquid/liquid hydrocyclone to use it in the run of separation of light dispersed phases to overcome all disadvantageous of the anile public figures of similar systems the features and benefits of this design are to include a compact design with high efficiency with construction corporals that provide superior corrosion and brook resistance for longer design life.CHAPTER 1INTRODUCTIONIntroductionA Liquid to Liquid hydrocyclone is a static machine that use centrifugal force and apply it on the liquid mixture which will render the separation of heavy and between the mixture compon ents (light and heavy components) of this liquid.A Liquid to Liquid hydrocyclone will normally consist of the below three sort outs (see figure 1)Cylindrical secanttionConical baseThe angleDSeriesCyclone3 2 human body Diagrams of a HydrocyclonesThe key difference between the centrifuges and Liquid to Liquid Hydrocyclones that the Hydrocyclones are passive separators where it capable to apply the modest amounts of centrifugal force, but the centrifuges are called dynamic separators which are usually able to concern more centrifugal force than The Hydrocyclones. Another difference between hydroclones and centrifuges devices is the cost where the Centrifuges are expensive machines because its often need sophisticated control but the Hydrocyclones doesnt contain moving parts and it usually doesnt contain controls systems and because of this it at all so they are lesser cost devicesThere are any types of a hydrocyclone where it could be used to separate solids from liquids or to separ ate liquids mixture of unlike density.The hydrocyclone is used in various actions in many industries, from degritting sewage guck to removing vege instrument panel oil cut backlets from stupefyd piss. The governing regulations are difficult to quantify because of the complexity of the politic dynamics with multiple phases in highly swirling streams. The majority of applications are in the processing of mineral ores however, and experience has dished develop a basis for predicting the hydrocyclone miscellany performance in these duties. The factors that feign performance, two process and hydrocyclone design, will be covered in this paper. The focus will be on providing schooling that an engineer who is designing a hydrocylone system will find useful.A cutaway of a hydrocyclone is shown in count on 2. The slurry enters the playing field of the hydrocyclone called the respite fountain full point from the entre predate pipe. The slurry is introduced next to the wall of the cylindrical door, which induces a swirling action. foresee Hydrocyclone Cutaway1This action helps develop the inertial forces that enable the sorting of parts indoors the hydrocyclone. The slurry is further accelerated in the conical sections of the separator. The swirling action dumbfounds a nonaggressive go in the midpoint of the hydrocyclone where the finer, bring down-mass fragments migrate. The relatively light touchs are outside with the over judgment of conviction period stream by an upward swirling pay heed through the convolution lookout man. The heavier particles are removed with an under run away stream by a downward swirling flow through the superlative region of the hydrocyclone classifier. manakin Hydrocyclone, Tangential upper dissemination2 persona Hydrocyclone, Tangential Velocity distribution3Figure Hydrocyclone, Tangential Velocity Distribution4Figures 3 and 4 shows the mean axial and tangential components of the upper at different cross-sections in the upper portion of a 250-mm diam hydrocyclone (Petty et al., cc2). These integrity-phase numerical calculations were developed using the Reynolds averaged Navier-Stokes (RANS) equation, and standard transport equations for the Reynolds stress (RSM model) and the turbulence dissipation. The simulation imposes a back wedge on the invade and underflow streams to avoid the air core. The Reynolds look based on the military unitive diameter of the unravel entry and the loudnesstric flow rate of the feed stream is astir(predicate) 200,000. Figure 5 shows the pressure dispersion predicted by the simulation.The results, which are qualitatively similar to experiments by Kelsall (1952) and to multi-phase flow calculations declareed by Devulapalli and Rajamani (1994), predict a Rankine vortex flow with a maximum tangential stop number near the radius of the vortex finder (see Figure 4). This feature distinguishes hydrocyclone flows from other swirling flows enco untered in centrifugal separators. As illustrated by Figure 5, the swirling action of the flow field causes a lower pressure to develop in the core of the hydrocyclone. It is noteworthy that the Computational roving Dynamics (CFD) simulation captures the signifi push asidet qualitative flow features of a hydrocyclone classifier.Applications of Liquid to Liquid HydrocycloneIn pulp and paper mills.In the sector of water treatment industry.In petroleum industry sector to separate oil from water or water from oil.In Food industries.In chemicals industries. buttonic Parameters for Standard CycloneThe definition of a standard cyclone is that cyclone which has the victorian geometrical race between the cyclone diameter, deferral sector, vortex finder, peak curtain raising, and sufficient distance providing keeping time to proper(ip)ly classify particles. As with the involutes type design, the graphs and mathematical relationships shown for proper selection and sizing of cyclone s apply to the standard cyclone geometry. The principal(prenominal) parameter is the cyclone diameter. This is the internal diameter of the cylindrical feed sleeping accommodation. The next parameter is the area of the inlet nozzle at the record of entry into the feed chamber. This is normally a rectangular orifice, with the bigger belongings parallel to the cyclone axis. The basic area of the inlet nozzle skinnys 0.05 times the cyclone diameter squared. The next key parameter is the vortex finder. 3.jpgFigure Hydrocyclone Cutaway5The primary help of the vortex finder is to control both the separation and the flow leaving the cyclone. Also, the vortex finder is sufficiently extended below the feed entrance to forestall short circuiting of material involvely into the spill out. The surface of the vortex finder equals 0.35 times the cyclone diameter. The cylindrical section is the next basic part of the cyclone and is located between the feed chamber and the conical sectio n. It is the same diameter as the feed chamber and its function is to join on the cyclone and increase the retention time. For the basic cyclone, its length should be ascorbic acid% of the cyclone diameter. The next section is the conical section, typically referred to as the cone cell section. The include angle of the cone section is normally between 100 and 200 and, similar to the piston chamber section, provides retention time.Figure Involuted course vs. Tangential Feed6The termination of the cone section is the apex orifice and the full of life dimension is the inside diameter at the discharge point. The size of this orifice is headstrong by the application involved and must be large nice to permit the solids that entertain been classified to underflow to exit the cyclone without plugging. The normal minimal orifice size would be 10% of the cyclone diameter and can be as large as 35%. Below the apex is normally a splash skirt to help contain the underflow slurry.Const ruction of the Liquid to Liquid HydrocycloneA typical Liquid to Liquid hydrocyclone made of a conically shaped vessel this vessel open at its apex or underflow this is fixed to a cylindrical section which has feed inlet at the tangent. The top of the cylindrical section is congested with a plate which authorize through the axial mounted pipe of overflow and the pipe is leng hence into the body of the hydrocyclone by teentsy removable section known as the vortex finder the function of this vortex finder to prevent the short-circuiting provide directly into the overflow. The bottom of the vortex finder is protruding below the feed chamber. The feed chamber and the cones are seamed inside with the rubber or synthetic linings payable to the abrasive nature of most metallurgical slurries.The named material is made from hard rubber such as neoprene or urethane and the apex is fixed with a concentric hardwearing synthetic rubber (See Figure 8).Figure Construction of the HydrocycloneW orking Principle of Liquid to Liquid HydrocycloneThe Liquid to Liquid hydrocyclone generally is a closed vessel that knowing to make conversion for the incoming velocity of the liquid into rotary motion. This is gaind by direct inflow tangentially near to the top of a vertical cylinder where this will spins the entire contents of the cylinder and creating centrifugal force in the liquid so that the Heavy Liquid will go outward toward the cylinder wall, where they farm and a spiral down the wall to a port in the bottom of the ship and in the light of Liquid will move toward the axis of the hydrocyclone (see figure 9) where they will move toward the venthole which is exist at the top of the vessel.1Figure Working principle of the Liquid to Liquid HydrocycloneCHAPTER 2SIZING AND SELECTION OF HYDROCYCLONESPerformanceIn as real the proper size and number of cyclones required for a disposed(p) application, two main objectives must be considered. The first is the classification or s eparation that is required, and the second is the stack of feed slurry to be regaled. Before determining whether these objectives can be achieved, it is necessary to establish a base judicial admission as follows1. Feed liquid water at 20O C.2. Feed solids globular particles of 2.65 sp gr.3. Feed concentration less than 1% solids by volume4. gouge dispose 69 kPa (10psi).5. Cyclone geometry standard cyclone as described above sortHistorically, classification has been defined as the particle size of which 1% to 3% reports to the cyclone overflow with coarser particles reporting to the cyclone underflow. Recent investigations have defined classification as the particle size of which 50% reports to the overflow and 50% to the underflow, or the so-called D50C point. Figure 10 shows the typical relationship between particle diameter and the percent recovered to underflow. The portion of the skid near the 50% recuperation level is quite steep and lends itself readily to dete rmining an accurate particle diameter. Examination of the recovery curve near the 97% to 99% recovery level shows that the curve is nearly horizontal and a small derivative could change the micron diameter considerably.Figure 11 as well as shows that the positive recovery curve does not decrease below a certain level. This indicates that a certain amount of material is always recovered to the underflow and bypasses classification. If a comparison is made between the stripped-down recovery levels of solids to the liquid that is recovered, they are found to be equal. Therefore it is assumed that a percent of all size fractions reports directly to the underflow as bypassed solids in equal proportion to the liquid split. Then severally(prenominal) size fraction of the actual recovery curve is adjusted by an amount equal to the liquid recovery to produce the corrected recovery curve shown in Figure 10. As the D50C point changes from one application to another, the recovery curves respite, along the horizontal axis.Figure jot Diameter VS. Particle Recovery7In order to determine a single graph which represents the corrected recovery curve, the particle size of each size fraction is divided by the D50C value and a lessen recovery curve can be plotted, as shown in Figure 11. Investigations have shown that this curve remains constant over a tolerant range of cyclone diameters and operating conditions when applied to a slurry containing solids of a single particularized sobriety and a typical or normal size dissemination such as those encountered in most grinding circuits. equating 1 gives a mathematical relationship which can be used to get the lose weightd recovery. This recovery, along with the bypassed solids, is used to predict the complete size distribution for the underflow product.WhereRr = Recovery to underflow on corrected basis.X = Particle diameter /D50C particle diameter.Figure Reduce Recovery8In designing comminution circuits the objective is to produce an overflow from the cyclone which has a certain size distribution, normally defined as a given percent passing a specified micron size. An empirical relationship shown in flurry 1 is used to tie in the overflow size distribution to the D50C required producing the specified separation. The relationship of this table is for typical or average grinding size distributions and whitethorn neuter slightlyDepending upon the grinding characteristics of the ore itself. The separation a cyclone can achieve can be approximated using comparison 2. The D50C (base) for a given diameter cyclone is cipher times a series of rectification factors designated by C1, C2, and C3.Table race of D50C to Overflow Size DistributionRequired Overflow Size Distribution(percent Passing) of Specified micrometer caliper SizeMultiplies (To be Multiplied Times Micron Size)98.80.5495.00.390.00.9180.01.2570.01.6760.02.0850.02.78Example Produce an overflow of 80% passing 149 microns (100 meshes). Multiplier from Table 1 at 80% passing = 1.25.Micron size for application = 149 microns (100 mesh).D50C required = 1.25149 = 186 microns for application.This D50C (base) is the micron size that a standard cyclone can achieve operating under the base conditions and is given in Figure 12 or calculated from Equation 3. For example, a 25.4 cm (10 in.) diameter cyclone has a base D50C point of 24 microns.Figure Cyclone Diameter V.s D50 (For Typical Cyclones)9Where D = Cyclone diameter in cm. The first correction (C1) is for the decide of the concentration of solids contained in the feed slurry. The graphical representation of this correction is shown in Figure 13 and can be calculated using Equation 4. Figure 13 indicates that the level of percent solids is extremely important in determining the proper separation, as the higher(prenominal) the concentration the coarser the separation. It should be pointed out that this correction is a relative measure of slurry viscosity and is affecte d by such things as the size of particles present as comfortably as particle shape. For example, a feed that contains a large amount of clay would tend to breakout this curve to the left and result in a coarser separation, whereas the absence of fines would shift the curve to the right and result in a finer separation. numerous other variables such as liquid viscosity withal affect this correction.WhereC1 = Correction for the influence of cyclone feed concentration.V = Percent solids by volume of cyclone feed.Figure Correction for Feed Concentration10The second correction is for the influence of pressure repose across the cyclone as measurable by victorious the difference between the supply or feed pressure and with overflow pressure. Pressure drop is a measure of the energy being apply in the cyclone to achieve the separation. It is recommended that pressure drops, whenever workable, be designed in the 40 to 70 kPa (5 to 10 psi) range to minify energy requirements as wel l as reduce wear rates. This is especially true for coarse separations usually associated with primary or secondary grinding circuits. The correction for pressure drop is shown in Figure 14 and can be calculated from Equation 5. As indicated, a higher pressure drop would result in a finer separation and lower pressure drop in a coarser separation.WhereC2 = Correction for influence of pressure drop.P = Pressure drop in kPa.Figure Correction for Pressure reduce11The next correction is for the effect that specific gravity of the solids and liquid have on the separation. Since the cyclone does not actually achieve a size separation but quite a a mass separation, the specific gravity of the particle is extremely important in determining the separation. It is especially meaningful in applications where the mineral has a higher specific gravity than the gangue material which allows better liberation of mineral particles at a coarser overall separation size. It has been found that Stokes law can be applied to determine particle diameters which would produce the same ending settling velocity for a particle of known specific gravity in a liquid of known specific gravity as compared to a particle of 2.65 specific gravity in water. This relationship is shown in Figure 15 and can be calculated using Equation 6.WhereC3 = Correction for influence of specific gravityGS = ad hoc gravity of solidsGL = Specific gravity of liquid (normally 1.0)Figure Correction for Solids Specific Gravity (in water)12The cyclone diameter, along with the three corrections of percent solids, pressure drop, and specific gravity, are the main variables necessary for preliminary exam sizing and selection of cyclones. Other variables, such as the vortex finder and inlet size, also have an effect on separation. For example, a larger vortex finder size would tend to change the separation, whereas a smaller size would tend to achieve a finer separation. Due to this fact, most cyclones have a replac eable vortex finder with different sizes available. Vortex finder diameters vary from a minimum of about 25% of the cyclone diameter to a maximum of about 45%. The inlet area also shows the same effect as the vortex finder, but not as pronounced. The apex size also has an effect on separation but the effect is minor unless the apex is too small and becomes a physical constraint, forcing material into the overflow. Cyclone retention time is also a minor factor influencing cyclone performance. Within limits, increased retention time would help achieve a finer separation whereas reduced retention time would coarsen the separation. The retention time of the cyclone can be altered by either changing the length of the cylindrical section or by changing the cone angle.There are numerous other variables which also have an effect of separation however, these variables are relatively minor and may be neglected for the preliminary sizing and selection of cyclones.Flow consecrateThe second mai n objective which must be considered is to provide sufficient cyclone capacity for the application. The volume of feed slurry that a given cyclone can handle is related to the pressure drop across the cyclone. The relationship between flow rate and pressure drop for several different sizes of standard cyclones is shown in Figure 16. As shown, the flow rate increases as the pressure drop increases. In order to utilize this graph, the pressure drop used for cypher the separation is used to determine the flow rate for the cyclone diameter which was also used for determining the separation. The flow rate is then divided into the essential flow for a specific application to determine the number of units necessary. Since the flow rate given in Figure 16 is for water quite a than slurry, it should be mentioned that slurry normally increases the capacity of a cyclone over that shown for water however, for preliminary estimates this factor can be neglected. This will result in the number of cyclones calculated being slightly higher than those actually needed. Approximately 20% to 25% standby cyclones are recommended for operational as well as maintenance flexibility. The vortex finder size and inlet area of a cyclone also have an effect on the volumetric flow rate that a given cyclone can handle. Larger vortex finders or inlet areas would increase the capacity, whereas smaller vortex finders or inlet areas would decrease the capacity. The shaded area in Figure 17 corresponding to each standard cyclone gives the approximate range of capacity for each cyclone.Figure Pressure Drop V.s volumetrical Flow rate13Shown that an underflow density of 50% to 53% solids by volume is typical for primary grinding circuits, whereas an underflow density of 40% to 45% solids by volume is normal for regrind circuits. Therefore, an underflow density can be assumed which establishes the descend flow rate that must report through each cyclone apex. Figure 17 shows the approximate flow rate for a given diameter apex orifice.Figure Apex Capacity Diameter VS. Flow rate14Operational and Design ConsiderationsOne of the most important considerations is to insure that cyclones are installed properly. A lucubrate list of Dos and Donts is given in a later chapter.Feed Piping and DistributionA most important consideration for a given cyclone system is proper delivery of the slurry to the cyclone or cyclones. It has been found that a pipe size which produces a line velocity of 200 to 300cm/sec (7 to 10 ft/sec) is high enough to prevent particles from settling, even in horizontal sections, but low enough to minimize wear. Normally for a single cyclone installation the inlet pipe size of the manufacturers recommendation produces a velocity in this area. If the slurry is to be distributed to a number of cyclones operating in parallel, extreme care should be given to the design of the distribution system, and a radial type of heterogeneous is recommended. This is a system w here the cyclones are feed from a central circular chamber. When properly designed the central chamber becomes a mixing area and the line velocity should be lowered to approximately 60 to 90 cm/sec (2 to 3 ft/sec). This will help insure that each cyclone is fed with the same slurry concentration as well as the same particle size distribution and also will reduce wear rates. development the radial re-create also makes it easier to install standby cyclones. Should an inline type manifold be utilized, the cyclones do not receive good distribution. It is typical that the high mass particles or coarser particles tend to pass the first cyclones and report to the utmost cyclone. This results in the last cyclone receiving a higher feed concentration of coarser particles, which accelerates the wear of the last cyclone as well as produces a coarser separation due to the higher feed density. Also, the last cyclone, once shut off, becomes difficult to summarize because the solids will tend to pack into the feed pipe. For applications where the separation is not critical or one in which the feed concentration is extremely low, an inline manifold is acceptable and is much less expensive than the radial type.Pressure Drop CalculationAs mentioned earlier, the pressure drop across a cyclone is measured by taking the difference between the feed pressure and the overflow pressure. If the overflow is complete at near atmospherical pressure as recommended, the feed pressure is the same as the pressure drop. Cyclone selection provides the pressure drop required, and for pump calculations this must be converted to meters of slurry which can then be added to the static and friction heads to determine the total dynamic head for the pump. Equation 7 is used for conversion of pressure drop to meters of slurry.WhereM = Meters, slurry.P = Pressure drop, kPa.G = Sp gr of slurry.As stated, it is recommended that both the overflow and underflow products be discharged at atmospheric pre ssure. Should the overflow be discharged against a positive head, whatever of the fluid which normally reports to the overflow is forced to report to the underflow. This does not have a major effect on classification but does increase the amount of bypass solids and reduces underflow density. Should the overflow be discharged at a point lower than the feed entrance, a possible syphon can be established which would cause a dislocation in classification and could bring larger particles into the overflow. A large siphon effect could actually dislodge a worn liner which in turn would plug the overflow piping. Siphons can be prevented by instal a vent pipe on the overflow piping of each cyclone. The underflow should also be discharged at or near atmospheric pressure. Should the underflow be discharged at a negative pressure, the effect would be similar to a positive pressure at the cyclone overflow. If the underflow is discharged against a positive pressure, the amount of flow is redu ced and a larger apex must be selected in order to insure that theSUMP/ mettle DesignAnother chapter covers the selection and sizing of slurry pumps and should be consulted for more detailed information concerning cesspool/pump design. Specifically regarding cyclone applications, the feed slurry being delivered to a cyclone should be as steady as possible with regard to both volumetric flow rate and slurry density. Unsteady feed conditions such as severe pump surging or extreme variations in slurry density are very detrimental to good cyclone performance. In general, a sinkhole/pump system for a cyclone application should have a cesspool with as much depth as possible and a minimum cross-sectional area consistent with the pump manufacturers recommended retention time. A sump of this design will normally eliminate pump surging by allowing small variations in sump level well above the minimum pump suction level. The small cross-sectional area will reduce the buildup of solids in t he bottom of the sump and help prevent large sections of the colonized solids to slough into the pump suction and plug either the cyclone feed line or the cyclone apex. Therefore, a tall sump with a small crosssectional area provides much smoother operation.Apex Discharge PatternAn Important part of cyclone operation is being able to observe the type of pattern that the cyclone apex is producing. An apex operating at atmospheric pressure should produce a cone shaped discharge with an angle of 20O to 30O and a hollow center. If the cyclone consistently produces a high angle cone spray, the apex orifice should be reduced in size to maximize the slurry density being discharged. On the other hand, should the cone spray be void of the hollow center and resemble a rope, then the apex is too small and outsize material may be reporting to the cyclone overflow. In this case, a larger apex orifice should be installed.CHAPTER 3DESIGN VARIABLES, HYDROCYCLONE GEOMETRYHydrocyclone Inlet DesignHyd rocyclones designed prior to 1950 featured outer wall tangential feed entry and 12-15 mm thick rubber liners. This design was not comely for fine separations or for abrasive slurry applications. Most hydrocyclone manufacturers have redesigned their inlets to include some form of involutes, ramped or scrolled feed style and all of these provide a measured advantage in hydrocyclone performance compared to earlier tangential designs. Figure 18 illustrates the various types of hydrocyclone feed entries. The inlet opening or cross-sectional area of the orifice feeding into the cylindrical section of the inlet has an effect on capacity as well as D50, and most hydrocyclone models have several options to increase or decrease this area based on the desired flow rates and cutpoint. In general, the larger inlet area, the higher the hydrocyclone capacity and the larger predicted D50.piston chamber SectionTypically hydrocyclones have a cylinder section length equal to the hydrocyclone diameter . This can be a separate section or integral to the inlet head. Figure 19 illustrates a hydrocyclone without a cylinder section plus hydrocyclones with a single and double cylinder. While the longer cylinder section provided greater conformity time and thus more capacity, it also reduces the tangential velocity. The added cylinder length results in minimal improvement in hydrocyclone separation and will increase hydrocyclone capacity at the same pressure by 8-10%. Larger 660-840mm diameter hydrocyclones typically have shorter cylinder sections.Figure Hydrocyclone Inlet Styles15Figure Hydrocyclone Cylinder Length16Cone SectionFigure 20 illustrates the different hydrocyclone cone angles that are used in different applications. The 20-degree cones ha