Plate tower column

Packed vs Plate Columns. Relative to plate towers, packed towers are more useful for multipurpose distillations, usually in small (under 0.5 m) towers or for the following specific appHcations severe corrosion environment where some corrosion-resistant materials, such as plastics, ceramics, and certain metaUics, can easily be fabricated into packing but may be difficult to fabricate into plates vacuum operation where a low pressure drop per theoretical plate is a critical requirement high (eg, above 49,000 kg/(hm ) (- 10, 000 lb/(hft )) Hquid rates foaming systems or debottlenecking plate towers having plate spacings that are relatively close, under 0.3 m. 

However, in certain cases, the impingement plate design is preferred over packed-tower columns when either internal cooling is desired, or where low liquid flow rates would inadequately wet the packing. 

Platten-gewebe, n. lamellar tissue, -glimmer, m. sheet mica, -gummi, n. plate rubber sheet rubber, -kaik, m. slab limestone, -kautschuk, n. plate rubber sheet rubber, -kondensator, m. (Elec.) plate condenser, -kultur, /. plate culture, -kupfer, n. sheet copper, -pulver, n. (Expl.) rolled powder, flake powder, -achale, /. flat dish, specif. Petri dish, -turm, m. plate column, plate tower, -zink, n. slab zinc, plattgedriickt, a. flat-pressed, flattened, plattieren, jj.t. plate clad. 

Figure 24.1 Types of tower or column reactors for gas-liquid reactions (a) packed tower, (b) plate tower, (c) spray tower, (d) falling-film tower, (e) bubble column...

Absorption towers or columns 1 A7 packed tower 1 A7 plate tower 1 A7 spray towers 1 A7... 

For gas absorption, the equipment possibilities are generally packed columns plate distillation towers, possibly with mechanical agitation on every plate deep-bed contactors (bubble columns or sparged lagoons) and mechanically agitated vessels or lagoons. Packed towers and plate distillation columns are discussed elsewhere. Generally these... 

The absorption can be performed in different types of unit, for example spray tower, packed bed, plate tower, bubble column, static mixer, and bubble tank. Gas-liquid interfacial area and liquid fraction are criteria for equipment selection. 

Example 6 Determination of optimum reflux ratio. A sieve-plate distillation column is being designed to handle 700 lb mol (318 kg mol) of feed per hour. The unit is to operate continuously at a total pressure of 1 atm. The feed contains 45 mol% benzene and 55 mol% toluene, and the feed enters at its boiling temperature. The overhead product from the distillation tower must contain 92 mol% benzene, and the bottoms must contain 95 mol% toluene. Determine the following ... 

Countercurrent columns with additional kinetic energy input have found a broad range of industrial applications [42-48]. Examples of extraction towers with energy input are pulsed towers, pulsed packed columns and pulsed perforated-plate towers. A number of units with some form of mechanical agitation are also used (Karr column, Scheibel column, Oldshue-Rushton column, Ktihni column, RZE extractor, RDC and ARD extractor, Graesser contactor). 

In pulsed sieve-plate towers, the entire column cross-section is occupied with trays, and thus the lighter phase passes through the holes in the upward stroke and the heavy phase in the downward stroke. This will continuously create new interfaces, which improves the mass transfer. By low pulsation intensities the dispersed phase is discon-tinuously moving through the holes (mixer-settler mode). The appropriate relation... 

This led to the development of reciprocating plate towers which consist of a stack of perforated plates and baffle plates. The column developed by Karr (Fig. 2.18) reaches high maximum loads and is suitable for systems with low interfacial tension [44]. Here the perforated plates move up and down driven by an outside motor. The... 

Filters, heat exchangers, dryers, bubble cap columns, cyclones, etc., are ordinarily designed and built by process equipment manufacturers. However, units of special design for one-of-a-kind operations such as packed or plate towers are quite often designed and built under the supervision of plant engineers. Thus, there is a large variety of this type of equipment, none of it essentially standard. 

Venturi scrubbers are designed on the basis of the venturi flow-metering device. The flow channel is narrowed down so that the velocity will greatly increase at the throat. Then, as in the flow-metering device the flow channel widens ouf. For ease of fabricalion venturi scrubbers are designed with a rectangular cross section. The absorption fluid is injected into the Venturi at the throat where the velocity is the greatest. For particulate removal plain water could be used. As in the plate columns discussed above, for the simultaneous removal of particulate matter and sulfur dioxide, soda ash or caustic soda slurries could be used for absorption of the gas. Venturis are frequently used in conjunction with plate towers. They also serve as stand-alone removal devices in some cases. 

When column diameters are less than 0.6 m (2.0 ft) packed towers can be considerably cheaper. However, if alloy metals are necessary, plate towers may result in less cost. Using ceramic or other similar resistant materials for packing and materials of construction, packed towers can serve to handle corrosive materials and acids. Because the gas flow in packed towers may offer less degree of agitation, packed tower operation may be better for liquids that tend to foam. When liquids are thermally sensitive, packed columns may offer less holdup and thus prevent changes taking place in the liquids due to thermal reaction. 

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