Centrifugal separation force

Higher flow rates, q, increase the intensity of the centrifugal separation forces. 

In most cases, Murchison and Hutton being no exception, very high oil-removal efficiencies can be achieved with a reject ratio of -1 %. However, while this holds true for the majority of cases, the required reject rate is obviously influenced by the level of inlet contamination and may be related to the volumetric throughput and centrifugal separation forces. At lower flow rates, lower specific-gravity differences, or with small droplet sizes, it is likely that the central core will be less dense and some of the smaller, slower-moving droplets would not be captured In these cases, an increase in the reject rate beyond the characteristic breakpoint previously mentioned is likely to be of more benefit... 

A certain minimum flow rate is necessary to set up the vortex motion and to establish centrifugal separation forces that grow in intensity as the flow rate increases and improve the separation efficiency. A point will be reached for a given set of conditions, however, beyond which further increases in flow rate will cause performance deterioration. This is caused principally by the following. 

On the lower end of the flow range, efficiency falls off when the flow rate is reduced below 318 m3/d water [2,000 BWPD]. As discussed, this results because insufficient flow is available to set up the vortex motion and to produce the strong centrifugal separation forces required for optimum performance. These two points define the lower and upper flow-rate limits for acceptable performance. 

Adopting 60-mm [2.4-in.] cyclones, which operate at lower spin speeds for the same flow rate, resulted in smaller centrifugal separation forces. This probably results in a less dense central core, which requires a higher reject ratio to allow complete oil removal. Additionally, the TLP crude exhibits a high tendency to foam, which, when combined with the flash gas that exists preferentially in the reject stream, creates a foamy gassy mixture. This in effect reduces the Vortoil capacity because the flow rate needs to be limited to reduce Ato ensure that sufficient driving force exists. 

Particles entering a cyclone are subjected to a substantial centrifugal separating force, the force exerted... 

Centrifugal separators make use of the common principle that an object whirled about an axis at a constant radial distance from the point is acted on by a force. Use of centrifugal forces increases the force acting on the particles. Particles that do not settle readily in gravity settlers often can be separated from fluids by centrifugal force. 

Centrifugal Separation Centrifugal force can be utilized to enhance particle collection to several hundredfold that of gravity. The design of cyclone separators for dust removal is treated in detail in Sec. 17 under Gas-Solids Separations, and typical cyclone designs are shown in Fig. 17-43. Dimension ratios for one family of cyclones are given in Fig. 17-36. Cyclones, if carefully designed, can be more efficient on hquids than on solids since liquids coalesce on capture and are easy to drain from the unit. However, some precautions not needed for solid cyclones are necessary to prevent reentrainment. 

In a filtering centrifuge, separating sohds from liquid does not require a density difference between the two phases. Should a density difference exist between the two phases, sedimentation is usually at a much more rapid rate compared to filtration. In both cases, the solid and liquid phases move toward the bowl under centrifugal force. The sohds are retained by the filter medium, while the liqmd flows through the cake solids and the filter. This is illustrated in Fig. 18-138/ . 

Gas separation can be achieved with centrifugal separation techniques. Gas is forced through a... 

Centrifugal A driving force chat causes a body to move in a circular path, for example, a centrifugal fan, centrifugal separator, or centrifugal pump. 

Zentrifugal-abscheider, m. centrifugal separator. -geblUse, n. centrifugal blower or fan. -kraft, /. centrifugal force. -stoffmUhle, /. (Paper) centrifugal beater. 

Among many specialist types of centrifuge is the multistage machine which consists of series of bowls mounted concentrically on a vertical axis. The feed suspension is introduced into the innermost bowl and the overflow then passes successively to each larger bowl in turn. As the separating force is directly proportional to the radius of... 

In the case of a centrifugal separator (i.e., a centrifuge), the acceleration due to centrifugal force, which should be used in place ofg, is given as ra>, where r is the radial distance from the central rotating axis (m) and co is the angular velocity of rotation (radian s -). Thus, the terminal velocity Vj (ms ) is given as... 

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