Column pipe liquid distributor type

Figure 1335. Packed column and internals, (a) Example packed column with a variety of internals [Chen, Chem. Eng. 40, (5 Mar. 1984)]. (b) Packing support and redistributor assembly, (c) Trough-type liquid distributor, (d) Perforated pipe distributor, (e) Rosette redistributor for small towers. (0 Hold-down plate, particularly for low density packing.

For single- or multiple-bed columns, a distributor is needed for each bed. A center-fed packed distillation column, for example, requires at least two beds. In some cases, the cost of the distrib-utor(s) can approach that of the packing. One can select from several different types of liquid distributors, including trough, orifice/riser, perforated pipe, and spray nozzle. These are illustrated in Figure 12.55 and described below. 

The perforated-pipe distributor is best suited where vapor mass velocities are high and where an open area in excess of 70 percent is needed to avoid localized flooding (305). Together with the spray type, the perforated-pipe distributor offers the highest vapor flow area. However, the maximum liquid flow recommended for this type of distributor is relatively low and should not exceed 10 gpm/ft of column area (305) with standard designs. 

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