Ceramic saddles

Absorption and Drying Towers. Towers are typically carbon steel vessels lined with acid proof brick and mortar and packed with ceramic saddles (see Absorption). More recently, all metal towers having no brick lining have been built from high siHcon stainless steel alloys such as Sandvik SX or Saramet. 

Yi-in ceramic rings Yi- by 2-in polyethylene Tellerettes 1-in steel rings 1-in ceramic saddles 3.0 X 10- Unpiibhshed data for 4-in column, atmospheric pressure... 

Figure 9-28. Packing comparison at design point for IntaJox ceramic saddles, metal pall rings, and metal IntaJox . Reproduced by permission of American Institute of Chemical Engineers, Strigle, R. F., Jr. and Rukovena, F., Chemical Engineering Progress, Mar. (1979) p. 86 all rights reserved.

The D in. Intalox or Berl ceramic saddles would be the preferred choice because (1) the flooding point is sufficiently low and yet probably not too far from the load point (only flood data available, but would estimate 70-85% of load) (2) the surface area per cubic foot is essentially the same as for the existing 1-inch Raschig rings. By reference to the effective interfacial area graphs, and by using the Berl saddle data instead of Intalox as an estimate because it is not... 

A small tower 0.5 m diameter, 4 m high, packed with 25 mm ceramic saddles, packed height 3 m. 

Absorption column packed column, diameter 0.5 m, height 6.0 m, packing height 4.5 m, packing 25 mm ceramic saddles, design pressure 2 bar, material carbon steel. 

Measurements have been carried out for an industrial NOx absorption process [74], The absorption plant (Fig. 9.8) represents a sequence of four units used for the removal of nitrogen oxides from the waste gas of an adipin acid factory. Each unit is separated into two sections, thus, there are altogether eight columns of 2.2 m diameter and 7 m height each, which are connected countercurrently. To enhance the mass transport in the columns, 35 mm INTALOX ceramic saddles with a packed bed height of 3.2 m are used. The plant is operated at atmospheric pressure. 

Fig. 1.3. Top of H2S04-making ( absorption ) tower, courtesy Monsanto Enviro-Chem Systems, Inc. www.enviro-chem.com The tower is packed with ceramic saddles. 98.5 mass% H2S04, 1.5 mass% H20 sulfuric acid is distributed uniformly across this packed bed. Distributor headers and downcomer pipes are shown. The acid flows through slots in the downcomers down across the bed (see buried downcomers below the right distributor). It descends around the saddles while S03-rich gas ascends, giving excellent gas-liquid contact. The result is efficient H2S04 production by Reaction (1.2). A tower is 7 m diameter. Its packed bed is 4 m deep. About 25 m3 of acid descends per minute while 3000 Nm3 of gas ascends per minute.

Industrially, the process is carried out in towers packed with ceramic saddles. Acid descends around the saddles where it meets and reacts with rising HzO(g) laden gas. 

The H2S04 is made by trickling strong sulfuric acid down between ceramic saddles in a packed bed while blowing S03 gas up through the bed. 

Figure 10.1 Samples of ceramic saddles fresh from shipment, (a) Chipped saddles (6) nonuniform saddles. (John G. Kunesh, excerpted by special permission from Chemical Engineering, December 7, 1987 copyright by McGraw-Hill, Inc., New York, NY 10020.)...

Pieces of polypropylene saddles defmned at tenqioatuies of about 250T and passed through the support screen. Pieces were found in downstream equipment and blocked booster pump suction. When the still was opened, only 1 ft of the original 20 ft was found. Despite the loss, the amine was adequately regenerated. Repacking with ceramic saddles solved problem. 

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