Wood grids

Not much performance data available, but in gen- Wood Grids eral slightly better than Raschig ring, pressure drop slightly higher. High side wall thrust. 

Wood Grids Very low pressure drop, low efficiency of contact, high HETP or HTU, best used in atmospheric towers of square or rectangular shape. Very low cost. 

Molstad et al.<21> also measured the absorption of ammonia in water using a tower of 384 mm side packed with wood grids, or with rings or saddles, and obtained KGa by direct experiment. The value of k(,a was then calculated from the following relation based on equation 12.17 ... 

The absorption tower will contain nonstaggered wood grids of the following dimensions ... 

A significant difference has been found in the loss of ascorbic acid when food product is dried on metal trays versus wood trays. The difference was attributed mainly to the faster heat transfer rate and thus faster drying through the metal tray. However, the losses were less with the metal grid compared with the wood grid under similar drying conditions. 

Figure 6,29 Regular, or stacked, packings (a) Raschig rings, stacked staggered (top view), (6) double spiral ring (Chemical Processing Products Dioision, Norton Co.), (c) section through expanded-meial-lath packing, (d) wood grids.

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