Distributor common

Good gas distribution is necessary for the bed to operate properly, and this requites that the pressure drop over the distributor be sufficient to prevent maldistribution arising from pressure fluctuations in the bed. Because gas issues from the distributor at a high velocity, care must also be taken to minimize particle attrition. Many distributor designs are used in fluidized beds. The most common ones are perforated plates, plates with caps, and pipe distributors. 

Labeling. Labeling, controUed by FDA regulations, includes not only the affixed labels, but also the package inserts that provide mote detailed information. Trade, generic, or common name, dose, number of dose units present, and name and address of manufacturer and distributor ate requited. For nonptescription products, adequate directions for use ate requited. Prescription products must beat the phrase, "Caution Federal law prohibits use without a prescription" on theit labels. 

Automotive Refinish Paints. Paint for appHcation to automobiles after they have left the assembly plant is a significant market. Although some of this paint is used for fuU repainting, especiaHy of commercial tmcks, most is used for repairs after accidents, commonly just one door or part of a fender, and so forth. In order to be able to serve this market, it is necessary to supply paints that match the colors of aH cars and tmcks, both domestic and imported, that have been manufactured over the previous ten years or so. Repair paints for the larger volume car colors are manufactured and stocked, but for the smaller volume colors formulas are suppHed by the coatings manufacturer to the paint distributor that permit a reasonable color match for any car by mixing standard bases. 

There are two regions in the regenerator the dense phase and the dilute phase. At the velocities common in the regenerator, 2-4 ft/sec, the bulk of catalyst particles are located in the dense bed immediately above the air distributor. The dilute phase is the region above... 

Fnr stripping service, as in a glycol or amine contactor (see Chapt 7 a bubble cap trays are the most common. In recent years, there has b growing movement toward crimped sheet structured packing. Improved vapor and liquid distributor design in conjunction with struc-... 

Damaged or plugged feed nozzle(s) and/or damaged stripping steam distributor(s) are the common causes of mechanical failures that affect true conversion. Note that the apparent conversion, as discussed in Chapter 5, is affected by the distillation cut point and main column operations. 

Other more capital-intensive modifications include installing a dedicated air blower for the spent catalyst riser. The spent catalyst riser often requires a higher back-pressure than the main air blower to deliver the catalyst into the regenerator. Therefore, less total combustion air would be available if one common blower is used to transfer spent catalyst and provide combustion air to the air distributors. 

Diethanolamine (DEA), 2,2 -iminodiethanol di( -ethyloxy)aniline. HN-(CH2CH2OH)2, MW = 105.1. Sp. gr. = 1.097. Flash point = 280 °F. Also used as an absorbent for acidic gases in petrochemical operations. Hygroscopic. Available as a 98.5+% alkyl amine commodity product from various international manufacturers, including Texaco Corporation. Commonly available through chemical distributors. 

Dimethylaminoethanol (DMAE), also known as N,N-dimethylethanolamine (DMEA) HOCH2CH2N(CH3)2 MW = 89.1. Sp.gr. = 0.887. Flash point = 105 °F/40 °C. Available as a 98.5+% amine commodity product from various international manufacturers and commonly available through chemical distributors. 

Methoxy,w-propylamine (MOPA, or 3-MPA), CHgCXCH NHj, MW = 89.1. Sp. gr. = 0.874. Flash point = 73 °F/22 °C. Flammable and corrosive liquid. Commonly available through chemical distributors. Good thermal stability. 

The pipe distributor (often called a sparger) differs from the other two distributor types because it consists of pipes with distribution holes in them that are inserted into the bed. This type of distributor will have solids below it that are not fluidized. If this is not acceptable for a process, then this type of distributor cannot be used. However, the pipe distributor has certain advantages. It does not require a large plenum, the holes in the pipe can be positioned at any angle, and it can be used in cases when multiple gas injections are required in a process. A common type of pipe distributor is the multiple-pipe (manifold sparger) grid shown in Fig. 17-12. 

Due to the pressure drop requirements across the gas distributor for good gas distribution, the velocity through the grid hole may be higher than desired in order to minimize or limit particle attrition. Therefore, it is common industrial practice to place a length of pipe (called a... 

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