Packing grid type

The grid types of structured packing have very high capacities and very low efficiencies, and are typically used for heat transfer or for vapor scrubbing. The wire mesh and the crimped sheet types of structured packing typically have lower capacities and higher efficiencies than the grid type. 

Figure 9-6RR. Intalox Grid-type packing useful for fouling, solids and heat transfer high-strength, low-pressure drop, high capacity, better efficiency than most structured and random packing. Used by permission of Norton Chemical Process Products Corp., Bull. IG-1.

A typical gas-distillation column is shown in Fig. 3-16. The column itself is a small-diameter tube, usually on the order of 6 mm inside diameter, which contains the packing. The Heli-Grid type of pack-... 

In England as early as 1930 and again in the 1950 s an open grid-type packing was used for scrubbing SO2 with limestone. The grids were constructed from wood strips or slats that allowed high liquid-to-gas ratio and low pressure drop. The absorber was tested over a period of years with minimal process difficulty. Over 3,500 hr of operation have been reported with scale-free conditions (3). 

Fig. 37 Molecular structure of the ligands bptz and bppn. Middle portion of the packing diagram of [Ag2(bptz)3][Sbp6]2 depicting the anion and cation arrangement. Right portion of the grid-type structiue of [Ag2(bppn)4][PF6]4 depicting tt-n and anion-interactions...

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.)... 

Earliest type, usually cheaper per unit cost, but some- Grid Tile times less efficient than others. Available in widest variety of materials to fit service. Very sound structurally. Usually packed by dumping wet or dry, with larger 4r-6 in. sizes sometimes hand stacked. Wall thickness varies between manufacturers, also some dimensions a ailable surface changes with tvall thickness. Produce considerable side thrust on tower. Usually has more internal liquid channeling, and directs more liquid to walls of tower. Low efficiency. 

This is an open area packing with multiple layers of lattice-type panels. This grid, as described by the manufacturer s bulletin, consists of vertical, slanted, and horizontal planes of metal. The vertical strips have horizontal flanges oriented alternately right and left. Due to the random overlap, the vapor path must zig-zag through the bed. 

Fig. 6. Examples of types of meshes developed to resolve laminar flow around particles (a) Chimera grid. Reprinted, with permission, from the Annual Review of Fluid Mechanics, Volume 31 1999 by Annual Reviews www.annualreviews.org (b) Unstructured grid with layers of prismatic cells on particle surfaces. Reprinted from Chemical Engineering Science, Vol. 56, Calis et al., CFD Modeling and Experimental Validation of Pressure Drop and Flow Profile in a Novel Structured Catalytic Reactor Packing, pp. 1713-1720, Copyright (2001), with permission from Elsevier.

To avoid such flooding, the designer uses the corrugated bed support shown in Fig. 7.8. This grid will have over 100 percent open area. Crushed packing laying on even this excellent type of bed support can, however, cause flooding. 

---