Dumped packed towers

The use of packing factors is established in the design concepts of evaluating packed tower performance. Essentially all of the manufacturer s published data are for wet and dumped packing factors, F. Robbins proposes using... 

The problem we have just discussed—poor fractionation efficiency due to inadequate vapor and liquid initial distribution—is rather similar to tray deck dumping in trayed fractionators. And, just like trays, packed towers are also subject to flooding. 

Liquid redistributors are required every 5-10 tower diameters with pall rings, and at least every 20ft for other types of dumped packings. The number of liquid streams should be 3-5/fF in towers larger than 3 ft diameter. Some experts advocate 9-12/ft [27]. 

Tower packings are divided into three principal types those that are dumped at random into the tower, those that must be stacked by hand, and those known as structured or ordered packings. Dumped packings consist of units 6 to 75 mm I to 3 in.) in major dimension packings smaller than 25 mm are used mainly... 

Channeling is severe in towers filled with stacked packing, which is the main reason they are not much used. It is less severe in dumped packings. In towers of moderate size channeling can be minimized by having the diameter of the tower... 

So-called random or dumped tower packings are fabricated in shapes such that they fit together with small voids without covering each other. Prior to 1915, packed towers were filled with coke or randomly shaped broken glass or pottery no two towers would perform alike. 

Packings for towers are classified as dumped (random) or structured. When packings are used, the total purchase cost of the packed tower becomes... 

An FCCU fractionator is very much like a crude lower above the slurry oil section. Troubleshoof ing frayed crude towers has been covered in Chapter 1 and need not be repealed here. However, the process evaluation and operation of FCCU fractionators using structured—as opposed to dumped— packing is a topical subject and will be discussed in detail. The process engineer engaged in the operation of a packed FCCU fractionator has three concerns ... 

Tbe principal difiference between trayed and packed towers is that the packed tower uses metal rings instead of trays for vapor-liquid contact. The metal rings are dumped or packed into specific sections of the tower, called beds, and supported by cross grid bars spaced to prevent the rings from falling... 

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