Vessels diameter

The purification train. The oxygen is led from the cylinder through Ordinary flexible rubber condenser tubing to the constant level device A (Fig. 85). This consists of two concentric tubes (approximately 2 cm. and 0-5 cm. respectively, in diameter the inner tube being narrowed and curved at the bottom as shown) immersed in 50% aqueous potassium hydroxide contained in the outer vessel (diameter 3-5 cm.). Then by adjusting the liquid level in A the pressure of oxygen may be kept constant, and at a maximum of about... 

Fig. 7. Vessel support and arrangement where d = nozzle diameter, D = vessel diameter, and L = length. Saddles can be straight or tapered. Single supports can be used for small dmms. Combining dmms saves the number of necessary supports (7).

Dp = particle diameter, Df = vessel diameter, (note that D /Df has units of foot per foot in the equation), G = superficial mass velocity, k = fluid thermal conductivity, [L = fluid viscosity, and c = fluid specific heat. Other correlations are those of Leva [Jnd. Eng. Chem., 42, 2498 (1950)] ... 

Some performance data of plants with DEA are shown in Table 23-11. Both the absorbers and strippers have trays or packing. Vessel diameters and allowable gas and liquid flow rates are estabhshed by the same correlations as for physical absorptions. The calciilation of tower heights utilizes data of equilibria and enhanced mass-transfer coeffi-... 

Rotaiy wheel atomizers require 0.8 to 1.0 kWh/1,000 L. The lateral throw of a spray wheel requires a large diameter to prevent accumulation on the wall length to diameter ratios of 0.5 to 1.0 are in use in such cases. The downward throw of spray nozzles permits smaller diameters but greater depths L/D ratios of 4 to 5 or more are used. Spray vessel diameters of 15 m (50 ft) or more are known. The technology of spray drying is apphcable. 

Two complementai y reviews of this subject are by Shah et al. AIChE Journal, 28, 353-379 [1982]) and Deckwer (in de Lasa, ed.. Chemical Reactor Design andTechnology, Martinus Nijhoff, 1985, pp. 411-461). Useful comments are made by Doraiswamy and Sharma (Heterogeneous Reactions, Wiley, 1984). Charpentier (in Gianetto and Silveston, eds.. Multiphase Chemical Reactors, Hemisphere, 1986, pp. 104—151) emphasizes parameters of trickle bed and stirred tank reactors. Recommendations based on the literature are made for several design parameters namely, bubble diameter and velocity of rise, gas holdup, interfacial area, mass-transfer coefficients k a and /cl but not /cg, axial liquid-phase dispersion coefficient, and heat-transfer coefficient to the wall. The effect of vessel diameter on these parameters is insignificant when D > 0.15 m (0.49 ft), except for the dispersion coefficient. Application of these correlations is to (1) chlorination of toluene in the presence of FeCl,3 catalyst, (2) absorption of SO9 in aqueous potassium carbonate with arsenite catalyst, and (3) reaction of butene with sulfuric acid to butanol. 

Preliminary Process Flowsheet. This will show major equipment and lines, preliminary equipment details (vessel diameter, number of trays, pump flow and driver horsepower, etc.), major instrumentation, and, it is hoped, have a material balance at the bottom of each drawing with flows keyed to a numbering system on the diagram. The process flowsheets should cover both the process and utility sides of the plant. 

In hardwoods, morphological structural elements in longitudinal series comprise the segmented structure termed vessel . Vessels, which are exposed in transverse section, constitute about 10-46% of the stem volume in deciduous hardwoods and are cells of relatively large diameters (50-300 p.m). Vessels have in short the appearance of open vertical tubes within the wood structure because their end walls have partially dissolved. By comparison, the hardwood vessel diameter can be as much a 10 times the diameter of a softwood fiber. 

Standard Geometry describes a vessel and mixer design based on a fluid depth equal to vessel diameter and a top-entering impeller having a diameter equal to 1/3 of vessel diameter and located with a clearance of 1/3 of vessel diameter above the bottom of the vessel. 

Solution "Standard geometry" is appropriate for this application (see Figure 19). The vessel volume is 2 m The trial vessel diameter is computed as follows ... 

Permissible gas velocities are usually set by entrainment, and for a given throughput the vessel diameter is thus determined. The amount of catalyst or other bed particles is set by reaction kinetics and the bubble-solids contacting expected. Very often there is a scale-up debit involved in fluid bed reactors. As mentioned earlier, small reactors... 

Helieal serews operate in tlie laminar range at normally high impeller to vessel diameter ratio (D /D ) with a radial elearanee equal to 0.0375 D. The impeller usually oeeupies one-third to one-half of the vessel diameter. They funetion by pumping liquid from the bottom of a tank to the liquid surfaee. The liquid returns to the bottom of the... 

The larger of the diameters calculated by Equation 7-18 or 7-19 will set the minimum vessel diameter. Any choice of diameter equal to or larger than this diameter will be an acceptable choice. 

At very low superficial gas velocities (less than 2 ft/min) channeling of the gas through the bed may occur. Thus, it is preferred to limit the vessel diameter to ... 

In selecting acceptable combinations, the bed height should be at least 10 ft for H2S removal and 20 ft for mercaptan removal. This height will produce sufficient pressure drop to assure proper flow distribution over the entire cross-section. Thus, the correct vessel size will be one that has a bed height of at least 10 ft (20 ft if mercaptans must be removed) and a vessel diameter between df in and... 

In its simplest form, an adsorber is normally a cylindrical tower filled with a solid desiccant. The depth of the desiccant may vary from a few feet to 30 ft or more. The vessel diameter may be from a few inches to 10 or 15 ft. A bed height to diameter (L/D) ratio of higher than 2.5 is desirable. Ratios as low as 1 1 are sometimes used however, poor gas dehydration, caused by non-uniform flow, channeling and an inadequate contact time between the wet gas and the desiccant sometimes result. 

The usual practice in selecting a particular mesh for a given service is to determine the maximum allowable velocity and from this select a vessel diameter. In the case of existing vessels where mesh is to be installed, the reverse procedure is used, i.e., determine the velocity con-... 

Geometric similarity requires all corresponding dimensions of a new system to have the same ratio with a test model which has proven acceptable. These dimensions should include vessel diameter and liquid level, baffle width and number in vessel, impeller diameter, number of blades and width ratio. For example, a tank four times the diameter of the original model also requires a turbine ten times the diameter of the original turbine. 

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