GAS-DISTRIBUTION IN SHALLOW PACKED-BEDS

A shallow packed bed is defined as one where the bed diameter is great er than the packed height. Some shallow packed beds are more than 5-10 m in diameter. It is shown that gas distributors may be developed and evaluated in the laboratory by measurements of air flow through a geo metrically similar model of the full-scale plant. A maldistribution fa ctor is defined in terms of the velocity of the air emerging at 200 eq ually spaced positions at the top of the bed. Distributors are compare d in terms of the packed height required for the maldistribution facto r to reach its minimum value. In other experiments, measurements of th e air velocity below and above the bed and of the static pressure vari ation within the bed show how a rotating gas flow below a packed bed p roduces a maldistributed gas flow within the bed and how increasing th e depth of the bed reduces the maldistribution.