Collectors, centrifugal

Other Centrifugal Collectors. Cyclones and modified centrifugal collectors are often used to remove entrained Hquids from a gas stream. Cyclones for this purpose have been described (167—169). The rotary stream dust separator (170,171), a newer dry centrifugal collector with improved collection efficiency on particles down to 1—2 pm, is considered more expensive and hence has been found less attractive than cyclones unless improved collection in the 2—10-pm particle range is a necessity. A number of inertial centrifugal force devices as well as some others termed dynamic collectors have been described in the Hterature (170). 

Centrifugal collectors Separators for the removal of particulate matter from gas streams, classified as... 

Scroll collectors A centrifugal collector in which a scroll imparts a centrifugal motion to the dust stream, concentrating the dust in the peripheral layer, from where it is passed to a secondary collector, and then to exhaust. 

There are several types of wet collectors including spray towers, packed towers, and wet centrifugal collectors. The spray tower is a cylindrical or rectangular tower into which the incoming air is passed. Highspeed water sprays in the tower impact and remove the dust that is subsequently separated from the droplets by various types of eliminators. Spray towers are effective for all kinds of dust and even moisture-laden gases. 

A wet centrifugal collector is similar in principle to the dry centrifugal or cyclone collector except that the materials, gas, mist, vapor, or particulate is collected on wet surfaces. 

We will establish three internal structure physical models of wet centrifugal collector by Gambit 2.2 in this article, and then meshing. Solving three-dimensional velocity distribution, static pressure field distribution, turbulence characteristics of flow field of dust-laden air, the move track of different size of dust in the precipitator by Fluent 6.2. So as to choose optimal model. 

In a centrifugal collector the air stream moves in a cyclonic manner, resulting in a net centrifugal effect on the particle, causing it to move outward to the collection surface, from it drops into a dust collection... 

Inertial mechanisms used for particle removal depend on the fact that the radius of the path of a particle in a rapidly moving, curving airstream is larger than the path of the stream as a whole. Therefore, when a gas stream is spun by vanes, a fan, or a tangential gas inlet, the particulate matter may be collected on a separator wall because the particles are forced outward by centrifugal force. Devices utilizing this mode of operation are called dry centrifugal collectors. 

Fig. 16. Two-hquid flotation flow sheet (39). The original ROM is kaolin (white clay) that contains 11% impurity in the form of mica, anatase, and siUca. Treatment produces high purity kaolin and a Ti02-rich fraction. A, Kaolin stockpile D, dispersant (sodium siUcate plus alkah) W, water K, kerosene C, collector (sodium oleate) RK, recycled kerosene S, screen M, inline mixer SPR, separator CFG, centrifuge P, product and T, to waste.

FIG. 14-108 ( 7)Liqi lid entrainment from the bottom of a vessel by centrifugal flow. (Rietema and Veroer, Cyclones in Industry, Elsevier, Amsterdam, 1961. ) (h) Gas-oiitlet sldrt for liquid cyclones. (Stern et al. Cyclone Dust Collectors, Ametican Petroleum Institute, New York, 1955. )... 

All venturi scrubbers must be followed by an entrainment collector for the liquid spray. These collectors are usually centrifugal and will have an additional pressure drop of several centimeters of water, which must be added to that of the venturi itself. 

Mechanical Centrifugal Separators A number of collectors in which the centrifugal field is supphed by a rotating member are commercially available. In the typical unit shown in Fig. 17-45, the exhauster or fan and dust collector are combined as a single unit. The blades are especially shaped to direct the separated dust into an annular slot leading to the collec tion hopper while the cleaned gas continues to the scroll. 

For. 1 given cyclone collector, plot centrifugal force as a function of particle specific grav ity (0.5U-3.00), gas velocity (175-1750 m min ), and radius of curvature (30-250 cm)... 

Cyclone collectors are popularly used both for particle removal and for particle sampling (Fig. 13.1). The separation process of a cyclone relies on the centrifugal accelerations that are produced when particle-laden fluid experi-... 

Wet centrifugal A dust collector that uses water or other fluid in a centrifugal action in order to improve the particulate collection efficiency. 

A projection of this point of collector effluent vertically downward shows that a second high efficiency centrifugal trill be less than 50% efficient. A wet collector, fabric arrester and electro-static precipitator will be not less than... 

Cyclone and high efficiency centrifugals often act as primary collectors followed by fabric or wet type. 

Dust concentration determines need for dry centrifugal plant location, product value determines need for final collectors. High temperatures are usual and corrosive gases not unusual. 

Dry centrifugals used as primary collectors, followed by final cleaner. 

Operation Concen- tration Particle Sizes Cyclone High Eff. Centrifugal Wet Collector Fabric Arrester Hi-Volt Electrostatic See Remark No. 

Primary steam separators These devices are located horizontally, immediately above the top drum waterline and use baffles or chevrons and dry pipe collectors, or cyclone or centrifugal action to radically change the steam flow, resulting in the heavier water and contaminants separating out from the steam. 

He et al. (2002) used an off-line HPLC/CE method to map cancer cell extracts. Frozen ovarian cancer cells (containing 107 cells) were reconstituted in 300 pL of deionized water and placed in an ultrasonic bath to lyse the cells. Then the suspension was centrifuged and the solubilized proteins were collected for HPLC fractionation. The HPLC separation was carried out on an instrument equipped with a RP C-4 column, 250 mm x 4.6 mm, packed with 5-pm spherical silica particles. Extracted proteins were dissolved in 300 pL of DI water, and lOOpL was injected onto the column at a flow rate of 1 mL/min. Buffer A was 0.1% TEA in water and buffer B was 0.1% TFA in acetonitrile. A two-step gradient, 15-30% B in 15 min followed by 30-70% B in 105 min, was used. The column effluent was sampled every minute into a 96-well microtiter plate with the aid of an automatic fraction collector. After collection, the fractions were dried at room temperature under vacuum. The sample in each well was reconstituted before the CE analysis with 10 pL deionized water. The... 

---