Top-Tray Feed and Reflux Inlet Arrangements

TABLE 2.1 Dimensions for Top Feed/Reflux Inlet Arrangements 

Note 3 Ensure nozzle enters behind the baffle. If it does not, hydraulic jiunp could be a problem. 

Internal inlet pipes should be removable for maintenance. 

Arrangement b (often referred to as the false downcomer) is popular. It offers better liquid distribution than the others, does not suffer from hydraulic jump, and provides some flexibility in inlet nozzle orientation. The width of the false downcomer should be the same as the width at the bottom of a downcomer (307). For feed into center or off-center downcomers it is recommended to make the x -f- y dimension 12 in (307). If entrainment due to liquid splashing in the false downcomer is a concern, a horizontal baffle, with dimensions of about 2d by Wrf can be installed directly above the nozzle entry into the false downcomer. This baffle is installed at some clearance above the false downcomer. In most cases, there is no need for this baffle. 

Arrangement e is also popular. It is one of the least expensive arrangements, does not suffer from hydraulic jump, and minimizes inlet splashing. The baffle is open both at its sides and bottom. 

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Figure 2.1 Top-tray feeds and reflux-inlet arrangements. Dimensions for x, y, and z are listed in Table 2.1. (Henry Z. Kister, excerpted by special permission from Chemical Engineering, May 19, 1980, copyright 1980, by McGraw-Hill, Inc., New York, NY, 10020.)...

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