Sieve tray design procedure

Bolles s (1976) design procedure uses the sieve tray design procedure as a basis and modifies it as necessary. One major difference between valve and sieve trays is in their pressure drop characteristics. The dry tray pressure drop in a valve tray is shown in Figure 10-23 fBolles. 19761. As the gas velocity increases, Ap first increases and then levels off at a plateau level. In the first range of increasing Ap, all valves are closed. At the closed balance point, some of the valves open. Additional valves open in the plateau region until all valves are open at the open balance point. With all valves open, Ap increases as the gas velocity increases further. The head loss in inches of liquid for both closed and open valves can be e q)ressed in terms of the kinetic energy. 

Because of their proprietary nature, valve trays are usually designed by their respective vendors based on process specifications supplied by the customer. However, most fabricators publish technical manuals that make it possible to estimate some of the design parameters. The procedure for calculating valve-tray pressure drop outlined here has been adapted from the Koch Design Manual. As for the other column specifications required, they can be obtained via the same calculation procedures outlined above for the sieve-tray design. 

These items are covered in detail in texts on the subject such as Tribal (1980), Van Winkle (1969), Bolles (1963), Fair (1963), and Perry s Chemical Engineers Handbook (Perry and Green, 1984). Design data and procedures have also been published for specific tray column types. Sieve trays are reviewed by Chase (1967). Economopoulos (1978), and Bamicld and Davis (1989) valve trays by Bolles (1976) and slotted sieve trays by Smith and Delnicki (197S). 

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