Packing performance, random

Figure 9-6N(b). Fleximax high performance random metal packing available in two sizes and reported by manufacturer to be a fourth generation random packing. Used by permission of Koch Engineering Co., Inc., Bull. KFM-1. 

Nutter offers an improved high performance random packing identified as Nutter Ring, see Figure 9-6K. To achieve the best performance from any random packing, the liquid distributor must be level and the distributor points of the discharging liquid to the packing must be uniformly distributed, see earlier discussion on this topic. 

Nutter, D. E., F. C. Silvey, and B. R Stober, Random Packing Performance in Light Ends Distillation," Inst, of Chem. Engrs. (England), publication date not given. 

Structured packings are produced by a number of manufacturers. The basic construction and performance of the various proprietary types available are similar. They are available in metal, plastics and stoneware. The advantage of structured packings over random packing is their low HETP (typically less than 0.5 m) and low pressure drop (around 100 Pa/m). They are being increasingly used in the following applications ... 

Norton Chemical Process Products. IMTP High-Performance Random Packing Norton Chemical Process Products Akron, OH, 1996. 

One case has been reported (346) where random packings performed well in a 13.5-ft-diameter column even though the tray support rings were not removed. 

Performance in hi Hxessure/higMiquid-flow services. The ctq>acily and efficiency advantage of structured packings over random packii rapidly erodes as liquid rate or pressure increases (e.g., Fig. 8.12a). Numerous cases of structured pa ng failures have been eaq)erien< d 1 the industry in h -pressure and/or high-liquid rate services. Successful e q>eriences in such services have also been reported (24, 31a, 31c, 31d, 31e). 

Schmidt [9] introduced a concept for the design of columns packed with randomly filled 8—50 mm ceramic Raschig rings. He performed elaborate rectification tests in a column with a diameter of 0.3 m and a packing height of 2 m, using 7 binary mixtures at top pressures ranging between 66 and 1000 mbar, and used the results of... 

High-Performance Random Packing (Cascade Mini Rings) ... 

The still column is generally packed with random packing (structured packing can also be used for larger units) with one or two equivalent theoretical stages. One reflux coil is attached at the top section of the column, and the rich glycol from the contactor is used to condense some vapor in the column. This is done to generate some reflux for the proper performance of the column. 

One hundred tubes were taken as the representative sample population and all were integrated for three different density distributions and each at 3 different levels of runaway tubes (few, medium, and many tubes in runaway.) Altogether 900 integrations were performed and the results analyzed. Figure 9.8.1 shows the distribution of observed maximum ATs with the hundred tubes with 5% random packing variation and at beginning of runaways at 486 K wall temperatures. 

In addition, Chen" gives typical performance data for trays, random packing, and structured packing in Table 11. 

Chen [133] highlights the long-term growth of the technically popular use of bubble cap trays, valve and sieve trays, followed by the increased popularity of packed columns accompanied by the development of random and structured packings. There are some applications in chemical/ petrochemical/petroleum/gas treating processes where one type of contacting device performs better and is more economical than others. Chen [133] points out ... 

Eckert [125] provides some basic guidelines to good packing selection for various system performance requirements. Kunesh [126] illustrates the often-determined pressure drop advantage of random packed towers over the usual valve tray. See Figure 9-19 [126],... 

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