Grid packings

I. High-voidage packings, cooling towers, splash-grid packings... 

Grid packing is probably the newest type packing. It is lower in pressure drop, tind has higher capacity, and lower efficiency than the other types. (See Figures 9-6PP-9-6UU.)... 

Figure 9-6QQ. Nutter Snap-Grid high-capacity grid packing with good structural integrity (interlocking) and reduced fouling. Used by permission of Nutter Engineering, Harsco Corp., Bull. CSG-2.

Figure 9-6UU. Glitsch-grid packing. Style EF-25A. Used by permission of Glitsch, Inc., Bull. 163L84B.

The bottom section of the main column provides a heat transfer zone. Shed decks, disk/doughnut trays, and grid packing are among some of the contacting devices used to promote vapor/liquid contact. The overhead reactor vapor is desuperheated and cooled by a pumparound stream. The cooled pumparound also serves as a scrubbing medium to wash down catalyst fines entrained in the vapors. Pool quench can be used to maintain the fractionator bottoms temperature below coking temperature, usually at about 700°F (370°C). 

Howden An early flue-gas desulfurization process using a lime or chalk slurry in wooden grid-packed towers. The calcium sulfate/sulfite waste product was intended for use in cement manufacture, but this was never commercialized. The key to the process was the use of a large excess of calcium sulfate in suspension in the scrubbing circuit, which minimized the deposition of scale on the equipment. The process was developed by Imperial Chemical Industries and James Howden Company in the 1930s and operated for several years at power stations at Fulham, London, and Tir John, South Wales, being finally abandoned during World War II. British Patents 420,539 433,039. 

Grid packings, which are relatively easy to fabricate, are usually used in columns of square section, and frequently in cooling towers which are described in Volume 1, Chapter 13. They may be made from wood, plastics, carbon, or ceramic materials, and, because of the relatively large spaces between the individual grids, they give low pressure drops. Further advantages lie in their ease of assembly, their ability to accept fluids with... 

Norman, W. S. Trans. Inst. Chem. Eng. 29 (1951) 226-39. The performance of grid-packed towers. 

Purification. a-Methylstyrene was purified by distillation through a 6-foot, Heli-grid-packed, modified Podbielniak column under a reduced pressure of dry helium. Purity of the distillate was established by vapor phase chromatographic analysis, using flame ionization detection and an appropriate column. Sample purity generally ranged from 99.90 to 99.98%. 

Lead grid packed with with PbCri (cathode) spongy lead (anode)... 

Figure 8.14 (Continued) Common grid packings, (e) An element of Koch Flexigrid 1 (/) Three layers of Nutter 3 Snap-Grid tPort e, courtesy of Koch Engineering Company, Inc. part f courtesy of Nutter Engineering Corp.)...

Figure 6.14 (Continued) Common grid packings, (g) Perform Grid, tPart g from K. Hoppe, J. Keller and L. Krell, Chem. Engnr., February, 1978, p. 1 JO reprinted courtesy of the Institution of Chemical Engineers, UK.)...

For all charts (random, structured, and grid packings), the ordinate of the correlation is the capacity parameter, given by... 

This chapter presents an atlas of charts for interpolating flood, pressure drop, and MOC. For random and grid packings (Charts 10.1002 to 10.3517 and 10.8005 to 10.8205), the charts are plots of the Eckert generalized pressure drop correlation (GPDC) curves, with experimental data superimposed on them. These plots permit data interpolation... 

Fig. 6 Grid packing. Top, side, and end views of section of grid.

---