Modifications to Structured Packings to Increase Their Capacity
The hydraulic performance of structured packed columns is characterized by parameters such as loading point, flooding point, and dry and wet pressure-drop. These parameters can be positively influenced by optimizing the transition areas between two adjacent packing layers. Tests have been done in a two-phase test rig with a rectangular column made of perspex. The test medium is a liquid hydrocarbon in counterflow to saturated nitrogen gas. The performance of different packing structures at the layer-to-layer transition zone and the addition of vane-type elements between two packing layers was evaluated. Several packing modifications were tested and the results were compared with those of a non-modified packing. The intentions of this work are: to rank the modifications of structured packings with respect to the achieved capacity increase; to determine whether flooding is initiated in the core of the corrugated packing or in the transition area in spite of the modifications made on the lower or top side of the packing sheets; and to find out how the loading point is influenced by the modifications.
Effect of Structured Packing Characteristics on Styrene Monomer/Ethylbenzene Distillation Process
The application of various types of structured packings to separate styrene monomer/ethyl benzene in packed columns is presented. The investigation was conducted over a wide range of operating conditions such as packing type, pressure, and reflux ratio. Several structured packings were used for separation of styrene monomer/ethyl benzene and the optimum conditions were determined for each of them. The proper condition of separation process and appropriate parameters for achieving better efficiency was discussed. The calculated results were compared with those obtained in industrial scale. It was shown that Mellapak-Plus 252Y and 452Y packings can provide the maximum capacity with an acceptable level of efficiency over a wide range of operating conditions.
Enumeration of total coliforms, fecal coliforms, and Escherichia coli in foods by hydrophobic grid membrane filter: supplementary report.
Raw, comminuted poultry meat was used to determine the specificity of the media and incubation conditions used in the hydrophobic grid membrane filter method. Confirmation rates for target colonies were 100% for total coliforms, 98% for fecal coliforms, and 97-99% for Escherichia coli. The results of total coliform enumeration in 30 pasteurized milk samples by both the hydrophobic grid membrane filter method and AOAC method 46.013-46.016 are also reported.