Splash decks

Counterflow Trays Dualflow Multiple downcomer Baffle trays (splash decks) ... 

The internals for these columns have also been called splash decks or shower decks, descriptive terms to indicate the type of phase contacting expected. Vapor (or gas) flows upward through the baffle openings and there contacts the liquid showering down from one baffle to the next. Figure 12.42 shows a representative baffle tray column containing segmental baffles. 

The absorber is a simple splash-deck tower. Because the back pressure of hydrogen sulfide over Stretford solution is negligible, the absorber can be sized to reduce the inlet hydrogen sulfide concentration by a factor of 100,000. Commercial absorbers have met this design criterion. 

In a typical design, this tower will contain at least four open-type trays in the lower section and a minimum of seven fractionating trays in the upper section. The function of the lower section is to cool the incoming gas by sensible heat transfer with a pumparound of cooled quench oil (bottoms). This quench oil will leave the column at 350° to 400°F, and the pumparound will be cooled to between 270° and 330°F before being returned to irrigate the lower section trays. At least 90% of the components in the cracked gas feed that are heavier than C-lOs will be condensed by these angle trays, baffle trays, or splash decks. A small slip-stream of bottoms is sent to a stripper to remove the C-8 and lighter components, because the stripped bottoms have only fuel value. 

The lower sections of water quench towers typically employ baffle trays, splash decks, or angle trays. These devices have a very low efficiency, so that 6 to 12 actual trays are installed, which develop a pressure drop of only 0.02 psi per actual tray. If the effluent liquid from this lower section of the tower could be heated an additional 5°F, the useful heat available for cold section reboilers would increase from 77% to 82% of the total heat load on the water quench column. When this section is equipped with high capacity packing, the exit liquid temperature can be raised to within about 5°F of the inlet vapor adiabatic saturation temperature. This can be done without increasing the pressure drop compared to the trays. Normally a 10-ft to 14-ft depth of 70IMTP pacldng is specified for the lower section. Such a packed depth provides a 70% to 100% increase in theoretical stages compared to the trays that are replaced. 

Splash deck—Row of separated horizontal slats onto which liquid rains. 

Removable porcelain distribution nozzles Diffusion deck Splash board... 

The difficulties of such operations on the research platform Nordsee are described in Ref. 9. The Murchison platform was provided with a combination of impressed current protection and galvanic anodes because there was a limit to the load to be transported [12]. The anodes for platforms are installed and provided with cables at the yard. They are installed with redundancy and excess capacity so that no repairs are necessary if there is a breakdown. The lower part of the platform up to the splash zone is usually placed in position in the designated location at least 1 year before the erection of the deck structure so that impressed current protection cannot initially be put in operation. This requires cathodic protection with galvanic anodes for this period. This also means that the impressed current protection is more expensive than the galvanic anodes. 

Another type of crossflow cooling tower is the wet-dry tower, which consists of a normal crossflow tower over which a few air coils are placed. The hot water is first cooled by an air cooled heat exchanger and then drops to the wet cooling tower where more cooling is obtained by the evaporative mechanism. Figures 5 and 6 provide examples. In contrast, deck-filled towers contain tiers of splash bars or decks to aid in the breakup of water drops to increase the total water surface and, subsequently, the evaporation rate. 

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... 

In an atmospheric spray tower the air movement - is dependent on atmospheric conditions and the aspirating effect of the spray nozzles. Natural-draft cooling tower operation depends on a chimney or stack to induce air movement. Mechanical-draft cboling towers utilize fans to move ambient air through the tower. Deck-filled towers contain tiers of splash bars or decks to assist in the breakup of water drops to increase the total water surface and subsequently the evaporation rate. Spray-filled towers depend only on spray nozzles for water breakup. Coil shed towers are comprised of a combination structure of a cooling tower installed on top of a substructure that contains atmospheric section coils. Hyperbolic natural-draft cooling towers are typically large-capacity systems. 

These contain tiers of splash bars or decks to aid in the breakup of water drops to increase the total water surface and, subsequently, the evaporation rate. 

Picket fence weirs are used in low-liquid-rate applications (Fig. 8). Picket fence weirs can serve two purposes at low liquid rates. First, they reduce the effective length of the weir for liquid flow increases the liquid height over the weir. This makes tray operation less sensitive to out-of-level installation. Second, pickets can prevent liquid loss (blowing) into the downcomer by spraying. This occurs at low liquid rates when the vapor is the continuous phase on the tray deck. Picket fence weirs should be considered if the liquid load is less than 1 gpm per inch of weir (0.0267 ft /sec/ft, 0.00248 m /sec/m). At liquid rates lower than 0.25 gpm per inch of weir (0.00668 ft / sec/ft, 0.000620 m /sec/m) even picket fence weirs and splash baffles have a mixed record in improving tray efficiency. Operation at liquid rates this low strongly favors the selection of structured packing. 

Jetties are individual or multiple piles interconnected together to form a structure in the seabed and support a deck. The piles of a jetty usually have half of their length in the seabed and the rest in the high tide and splash zones up to the jetty deck. They are often concrete structures reinforced with steel. Cathodic protection using sacrificial zinc or aluminum anodes is installed after the completion of the jetty. With a deepwater jetty the suspension of more than a single anode or placing of alternate anodes at different levels is necessary. A few and larger anodes are necessary while impressed current method is employed. An... 

Similar studies have been carried out for the bottom of the deck, which has a cover thickness of 7.62 cm, and the results are shown in Fig. 12.10. The chloride concentration at the rebar surface increases more rapidly for 5.08 cm cover thickness compared to 7.62 cm. Because the top of the deck is not in the splash zone, the surface chloride content is lower than the bottom part. Corrosion onset will start at the bottom deck first and lead to eventual structure failure. 

Waterfront structures are exposed to a variety of marine environments. The resistance of materials to each of these environments may vary considerably, as weU as appHcabil-ity of various forms of corrosion control in mitigating the anticipated corrosion. The waterfront environment can be divided into five exposure zones sediment, immersion, intertidal, splash/spray, and atmospheric. In most cases, a single type of material will be used for the sediment, immersion, and intertidal zones. In some cases another material may be used for the splash and spray and atmospheric zones of the structure. An example of this would be the use of a reinforced concrete deck over steel pilings. Due to differences in corrosion activity between these zones, the corrosion performance of many materials is substantially different when exposed to two or more of these zones. Figure 1, taken from Ref 4, shows the result of a classical experiment where the corrosion of a continuous strip of... 

Conductive concrete splash zone deck, substructure... 

Precisely, the mass transfer undertaken in the vertical direction above the tray deck is complicated as shown typically in Fig. 4.25, involving jetting, dispersed bubbles, splashing as well as the generation of liquid drops as entrainment in the tray spacing. Usually, it is divided into three zones, i.e. 

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