Capacity, packings upper limit

Based on the above, some designers argued (5,15,57) that the traditional approach of using the flood point as the upper capacity limit of a packed column is best abandoned. They recommended shifting to alternate criteria such as maximum operational capacity or maximum permissible pressure drop. Others (3,37,41,51,58-60) stick with the flood-point criterion while recognizing its limitations. There are strong, practical reasons for retaining the flood point as the prime criterion for the upper capacity limit. 

Linear dynamic range of the 30 ii TCD is good when used with a packed column. When the 30)ii TCD is coupled with WCOT columns, the limited sample capacity of the columns severely limits its analytical utility. While the dynamic range can be somewhat adjusted by judicious selection of the split ratio of a capillary Injector, major and trace components can not be both simultaneously determined. The upper end of linear range is always limited by column capacity. 

Normally, the upper surface of the packed bed is at least 6 in. below a liquid distributor or redistributor. The bed limiter or hold-down plate is located on top of the packed bed in this space. It is important to provide such a space to permit gas disengagement from the packed bed. Such a space allows the gas to accelerate to the velocity necessary to pass through the distributor without exceeding the capacity of the packing. 

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