Maldistribution, trays multipass

Maldistribution Maldistribution can cause major efficiency reduction in multipass trays (>two passes). Further discussion is given under Number of Passes. ... 

Bolles (191) correlated the reduction in efficiency in terms of the distribution ratio, i.e., the maximum-pass LfV ratio divided by the minimum-pass LfV ratio. The L and V for each pass are determined from the normal pressure balance and hydraulic relationships, applied to each pass. At high distribution ratios, a substantial drop in tray efficiency occurs. Bolles shows that if this distribution ratio is kept lower than 1.2, the loss in efficiency due to maldistribution is negligible. Bolles recommends designing multipass trays for such low distribution ratios. Detailed guidelines for achieving low distribution ratios (<1.2), thus minimizing the effects of pass maldistribution on efficiency, are contained in a companion book (1) and in Bolles s paper (191). 

Unlevelness may induce liquid maldistribution, and thereby lower efficiency in multipass trays (177). Specifically, it has been stated (211, 399) that a series of multipass trays tilted in the seime direction will suffer a severe efficiency loss. 

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