Dry towers

The 94% acid from the sulphur dioxide drying towers (above) is used here and its strength brought up to 98 %. This is concentrated sulphuric acid. Stronger acid up to 106% may also be made. This concentration is suitable for sulphonating in, for example, the detergent industry. 

Acid circulated over SO absorbing towers is maintained at about 98.5% to minimize its vapor pressure. Where lower concentration product acid is desired, it is made either in separate dilution faciUties, or in drying towers operated at 93—96% H2SO4. 

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. 

In drying towers of sulfur-burning plants, mesh pads or inertial impaction-type mist eliminators are usually adequate. High efficiency mist eliminators are usually used in drying towers of spent acid or metallurgical plants. 

Fig. 7. Plant for spray-drying of detergents and soaps. 1, Burner 2, air combustion 3, cold air fan 4, hot air generator 5, spray-drying tower 6, cleaning ring 7, no22les circuit 8, tower suction cyclones group 9, tower suction fan 10, double-flap dischargers 11, recovery powder cyclone 12, recovery powder fan 13, belt conveyor 14, air lift 15, air lift suction cyclones 16, air lift suction fan 17, double-flip dischargers 18, vibrating sieve.

The function of the trap is to condense the hexane from the n-butyl-lithium solution. The checkers used a 1-L three-necked flask fitted with a short delivery tube (a quick fit air bleed tube was used), stopper, and rubber tubing connection. The submitters used a water aspirator and a 1-L filter flask with a drying tower between. 

Another type of crossflow cooling tower is the wet-dry tower, which consists of a normal crossflow tower over which a few air coils are placed. The hot water is first cooled by an air cooled heat exchanger and then drops to the wet cooling tower where more cooling is obtained by the evaporative mechanism. Figures 5 and 6 provide examples. In contrast, deck-filled towers contain tiers of splash bars or decks to aid in the breakup of water drops to increase the total water surface and, subsequently, the evaporation rate. 

A sulfuric acid drying tower uses 98% acid for drying an incoming air stream. The pilot plant tests show that 15 ft of 1-in. ceramic Intalox packing will do this job. The plant scale rates are ... 

In a 2-1. three-necked flask fitted with an efficient reflux condenser, stirrer, and pressure-equalizing dropping funnel are placed 216 g. (2.0 moles) of anisole (Note 1) and 400 ml. of methylene chloride (Note 2). The reflux condenser is attached to a drying tower. The solution is brought to reflux temperature with a heating mantle, and 167 ml. (278 g., 2.06 moles) of sul-furyl chloride (Note 3) is added dropwise over a 3-hour period. When the addition is complete, heating is continued for an additional 15 hours (Note 4). 

FIG. 18 Neutralization section. M, mixer T, tank C, condensor ST, settling tank DT, drying tower. 

Chlorine gas, produced by electrolysis of brine, was dried by passage through a mist of sulfuric acid in a drying tower, where static charge was generated. An explosion in the tower, (presumably involving hydrogen as fuel) was attributed to initiation by static spark. 

Before finally assembling the apparatus, the various units are charged as follows A is one-third filled with water to serve as a bubble counter. Generator B is about one-quarter filled with dry arsenious oxide, pea size or powdered. Drying towers G and H are filled with anhydrous calcium chloride. (It is well to place a wad of glass wool in front of the entrance and exit tubes.) In each of the two absorption bottles J and K is placed 200 g. of ethyl malonate. Dish L is filled with an ice-salt freezing mixture. 

A) 2-Bromophthalide.—The apparatus shown in Fig. 6 is used for the bromination. Flasks A and B are of 200-cc. capacity. Bromine is introduced by means of a current of carbon dioxide, which passes through mineral oil or sulfuric acid in the bubble counter, then through the bromine in flask B, and finally through the drying tower. The tower is conveniently made from a condenser jacket and is filled with anhydrous calcium chloride. Flask A is surrounded by an oil bath and is equipped with a thermometer, an outlet tube of wide bore connected to a gas absorption trap, and a gas inlet tube having an inside diameter of 2 mm. The inlet tube reaches to the bottom of the flask. 

One should not pour the liquified ammonia directly out of the cylinder since particles of iron compounds might be carried along, catalyzing the formation of sodium amide. For the exclusion of moisture it is also necessary to use a drying tower (potassium hydroxide) between the cylinder and the flask. 

Aqueous solutions Spray drying Spray drying tower... 

Powder (in spray drying tower) Mean particle size, Air / liquid mass flow ratio, Dmean Mr Kim-Marshall equation [26] 0.4 0.32... 

The methylamine generator consists of a i-l. flask fitted with a dropping funnel and outlet tube, which in turn is connected to a 25-cm. drying tower containing soda-lime, followed by a i-l. safety trap (Note 1). In the flask is placed 200 g. of technical sodium hydroxide flakes, and 263 g. of a 33-35 per cent solution of methylamine in water (Note 2) is dropped in slowly at such a rate that an even current of gas is evolved. When the addition has been completed and the gas bubbles very slowly into the... 

Chlorine drying towers See Hydrogen Oxygen, Sulfuric acid See Chlorine... 

Drying agent. A solid material, such as alumina, with a large surface area per unit weight that readily adsorbs moisture, i.e., moisture will collect on its surface. Used in gas drying towers and other applications that require the removal of moisture for quality control. 

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