Prospectus

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DST-31 Performance of Large Fixed-Valve Trays under Vacuum Expected Benefit toMembers: Improved confidence in designing fixed-valve trays for operation in vacuum-service, particularly for fouling applications. Present Situation and Proposed Research: Traditional Research Idea

Estimated Unit Time: Unknown. Estimated Additional Costs (Beyond Unit Time): Unknown. Background and Discussion: Figure 19 from TR-135, illustrates the relatively poor performance and narrow operating range of the one large fixed-valve tray that FRI has tested under vacuum. It would be very useful to have a more thorough understanding of how to design fouling-resistant trays for vacuum operation.

In clean services, packing is typically preferred for vacuum applications, because of its lower pressure drop per stage. However, in fouling services, packing is not a suitable choice, and fixed-valve trays (with relatively large valves) are often specified. Existing FRI data from tests of the Norton Triton Tray (TR 135R), which is typical of a large-valve design) show much poorer efficiency under vacuum than at pressure. It is not clear whether this performance is specific to the tray design tested, or inherent to the use of fixed-valve trays under vacuum. It is proposed to test a large fixed valve tray (e.g. Sulzer UFM AF, Koch-Glitsch Pro-Valve, or equivalent) with a design that is optimized for vacuum operation. The goal is to get insight into pressure drop and efficiency that would better enable members to design trays for these applications. This test would also give us insights into how well rules of thumb about turndown (minimum dry tray pressure drop, tray stability, etc. apply to these sorts of trays under vacuum operation conditions. Proposed Internals and Test System: Large fixed-valve trays (UFM-AF, ProValve, or equivalent), in C6/C7 service at 5 psia and 24 psia.

PROSPECTUS

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