Baffle Trays

FIG, 26-21 Quench tank with direct-contact baffle tray section. 

Mass-Transfer Contact Section Where there is a strong possi-bihty that not all of the incoming vapors will be condensed in the pool, a direct-contact mass-transfer section is superimposed on the quench tank. This can be a baffle-tray section (as shown in Fig. 26-21) or a packed column sec tiou. 

Fair [211] has presented and reviewed many studies of baffle tray, or splash/shower deck distillation columns. Figures 8-153 and Figure 8-154 illustrate a simple tray arrangement. The performance of the column is based on... 

Figure 8-153. Simple side-to-side baffle arrangement, with liquid flow cascades, for baffle tray column. Used by permission. Fair, J. R., Hydrocarbon Processing, V. 72, No. 5 (1993) p. 75, Gulf Pub. Co., all rights reserved.

Example 8-42 Mass Transfer Efficiency Calculation for Baffle Tray Column (used by permission [211])... 

Thus, a 20-foot baffle tray section, with 50% cut baffles on 24-in. spacing can contain 10 elements and produce 5.2 theoretical stages of separation. A corresponding crossflow sieve tray section, with 10 trays at 90% efficiency (16), can produce 9 theoretical stages. This ratio is about as expected. 

The three primary devices used in this service are (a) open spray columns,(b) packed columns, and (c) tray columns, which are perforated plates, baffle trays, etc. ... 

Figure 10-173. Direct contact tray column for heat transfer. This could be a baffle tray, sieve type tray, bubble or other contact device, or open spray or random packed column. (Symbols only used by permission Smith, J. H. Hydrocarbon Processing, Jan. 1979, p. 147. Gulf Publishing Company. All rights reserved.)...

E. Baffle Tray Column (or, Termed Shower Deck, No Holes, Caps, or Other Contact Devices)... 

M, = average molecular weight of vapor, m = exponent for baffle tray columns. 

Some types of scrubbers that can handle fouling streams, and baffle trays that can handle fouling and solids-containing streams. 

The column, pumps, and piping in contact with the hot fatty add are made from corrosion-resistant stainless steel. The column is a hollow vessel, containing no baffles, trays, or packing material of any kind The quality of the hydrolyzing operation is determined by the degree of split obtained on the fat. lbe fatty acid stream contains very little free glycerin, if any. 

Baffle Trays Baffle trays ( shed decks, shower decks ) (Fig. 14-28 ) are solid half-circle plates, sloped slightly in the direction of outlet flow, with weirs at the end. Gas contacts the liquid as it showers from the plate. This contact is inefficient, typically giving 30 to 40 percent of the efficiency of conventional trays. This limits their application mainly to heat-transfer and scrubbing services. The capacity is high and pressure drop is low due to the high open area (typically 50 percent of the tower cross-sectional area). Since there is not much... 

FIG. 14-28 Baffle tray variations, (a) Segmental, (b) Disk and doughnut, (c) Multipass, (d) Angle irons. 

Liquid-liquid extraction can take place in a column with various internals to foster contact between the dispersed and continuous liquid phases. Internals can include sieve trays, baffle trays and packing, as well as mechanical agitation and pulsing of the liquid. 

Several types of internals have been proposed so far. Some studies are presented by Volkct al. (VI2) and Grekelet al. (G15), who studied several arrangements of tubular internals and baffle trays. Volk suggested vertical tubes to increase the contact efficiency. For fluidized beds with diameter of 5-198 inches, conversions for beds of the same equivalent diameter (cf. Section I,C) were found equal. A large heat-exchange surface in the fluid bed is necessary for non-isothermal reactions, so the use of vertical tubes is quite practical. 

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