Perforated spargers

Use of efficient olefin feed distributors is also effective in reducing acid consumption. The conditions at the point of initial olefin contact with the circulating catalyst are very important because of the extremely rapid rate of the initial reaction. Perforated sparger rings are frequently employed, and a concentric feed nozzle is also a common feature 6). 

Internal pipe distributors are also known as perforated spargers or perforated pipe distributors or headers. They can be designed for either liquid only or two phase flow. A pipe distributor may be considered as liquid service if the volume of vapor is no more than 5%. 

Coarse bubble systems are typically found with orifice, perforated disks, or pipe spargers. Under most reaUstic conditions, bubbles of about 4—6 mm are formed. Eor a wide range of sizes... 

Steam is introduced at the base of the whiskey column through a sparger. Where economy is an important factor, as in a fuel alcohol plant, a calandtia is employed as the source of indirect heat. The diameter of the stiU, number of perforated and bubble cap plates, capacity of the doubler, and proof of distiUation are the critical factors that largely determine the characteristics of a whiskey. 

Bubble Reactors In bubble columns the gas is dispersed by nozzles or spargers without mechanical agitation. In order to improve the operation, redispersion at intei vals may be effected by static mixers, such as perforated plates. The liquid may be clear or be a slurry. 

The following equations can be used to design perforated plates, spargers, and bubble-cap types of grids ... 

There are three basic types of clean inlet gas distributors (1) a perforated plate distributor, (2) a bubble cap type of distributor, and (3) a sparger or pipe-grid type of gas distributor. The perforated plate distributor (Fig. 17-10d) is the simplest type of gas distributor and consists of a flat or curved plate containing a series of vertical holes. The gas flows upward into the bed from a chamber below the bed called a plenum. This type of distributor is easy and economical to construct. However, when the gas is shut off, the solids can sift downward into... 

Figure 3.29 Gas-phase distributors (a) porous plate, (b) perforated plate, (c) single-orifice nozzle, (d) spider-type sparger, and (e) multiple-orifice nozzle...

In the practice of the sparger design, it is very important to maintain equal flows through each orifice. For a perforated-pipe sparger the following three factors have to be calculated [27] ... 

FIG. 14-95 Comparison of bubbles from a porous septum and from a perforated-pipe sparger. Air in water at 70°F. (a) Grade 25 porous-carbon diffuser operating under a pressure differential of 13.7 in of water, (b) Karbate pipe perforated with 1/16-in holes on 1-in centers. To convert inches to centimeters, multiply by 2.54 °C = SA (°F - 32). (National Carbon Co.)... 

Perforated-Pipe Distributors The simple perforated pipe or sparger (Fig. 6-34) is a common type of distributor. As shown, the flow... 

Bubble columns. These are columns full of liquid into which gas is introduced by a perforated pipe or a sparger. Bubble columns are used for applications similar to stirred tanks, but their contact efficiency is lower. 

Slurry Reactors Slurry reactors are akin to fluidized beds except the fluidizing medium is a liquid. In some cases (e.g., for hydrogenation), a limited amount of hydrogen may be dissolved in the liquid feed. The solid material is maintained in a fluidized state by agitation, internal or external recycle of the liquid using pipe spargers or distributor plates with perforated holes at the bottom of the reactor. Most industrial processes with slurry reactors also use a gas in reactions such as chlorination, hydrogenation, and oxidation, so the discussion will be deferred to the multiphase reactor section of slurry reactors. 

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