Splash baffle

Some judgment is required in the use of these correlations because of construction features of the condenser. The tubes must be supported by baffles, usually with maximum cut (45 percent of the shell diameter) and maximum spacing to minimize pressure drop. The flow of the condensate is interruptea by the baffles, which may draw off or redistribute the liqmd and which will also cause some splashing of free-falling drops onto the tubes. 

Fill Packing Specially designed baffling used to provide a large surface area for heat transfer. Two classes of materials are used splash bars of wood, metal transite or plastic and film pack (cellular fill). The splash type cools the water as the droplets bounce down a series of bars in the air stream film packing converts droplets into a thin film. 

For center downcomers as in a two-pass design, the throw must be conservatively less than a distance that would cause the opposing streams entering the same downcomer to interfere with each other. Sometimes the installation of a splash baffle will help avoid conditions leading to flooding and loss of tray efficiency. 

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... 

Steam flow restrictions. Operating a boiler that has a restricted steam flow due to blockages or deposits in the chevrons, baffles, collecting pipes, splash plates, or pans (perhaps resulting from longterm adverse water chemistry conditions) may cause localized high steam velocities that lead to carryover. 

Poorly operating interface-level controllers can upset the interface level and cause a loss of water resulting in oil being dumped out. There is also the problem of improperly positioned inlet splash baffles within the vessel and this can cause problems regardless of the chemical. This, in most cases, can only be eliminated by removing or repositioning the baffle... 

Louvers—Baffles used for changing the direction of air flow into the tower in a uniform, parallel manner, and for preventing water droplets from splashing out of the tower as they fall through the structure. 

Low liquid rates. With the aid of serrated weirs, splash baffles, reverse-flow trays, and bubble-cap trays, low liquid rates can be handled better in trays. Random packings suffer from liquid dewetting and maldistribution sensitivity at low liquid rates. 

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. 

Picket fence weirs are also used to balance flow to the different passes on trays that have more than two flow paths. Splash baffles are an alternative to picket fence weirs when the major problem is blowing. 

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. 

Notes All runs with cyclohexane/n-heptane mixture at total reflux. The SRP column contained a splash baffle. FRI efficiencies are corrected from overall column to point. 

Picket fence splash baffles. These are placed on top of downcomers or weirs to break up foam entrainment or froth. 

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