Guidelines for Distributors and Multipass-Tray Inlets

Feed inlet distributors are recommended for large-diameter singlepass trays (207, 354). In multipass trays, feed and reflux distributors are essential to ensure uniform distribution. The only exceptions are 

Pure liquid feeds into two-pass trays, which can be introduced into the central downcomer by arrangements similar to those shown in Fig. 2.1 (arrangements a, b, d, g, h) and Fig. 2.2 (arrangement a). 

When feed to multipass trays is to be split unevenly, such as in a three-pass tray. In such cases, a feed trough (Fig. 2.4) is often preferred to a distributor (179, 307). 

The guidelines listed earlier for reflux, top-tray, and intermediate feed inlets apply whether a distributor is used or not. In addition, guidelines for avoiding operating problems unique to distributors are listed below. 

This guideline need not be adhered to when the quality of inlet stream distribution is not of major importance, e.g., when distributing feed to a single-pass tray or to the center area of a two-pass tray. 

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