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Aeration velocity

The same kind of phenomenon was not observed when distributor plate was located closer to the draft tube inlet atL = 14.1 cm and when only No. 7 and No. 8 or No. 7 and No. 3 flows were used. When all three flow injection locations were used, substantial improvement in solids circulation rate is possible even at L = 14.1 cm as shown in Fig. 9. The critical downcomer aeration velocities (superficial velocities based on downcomer area) for the data shown in Fig. 9 were determined through tracer gas injection experiments to be 0.29 m/s at L = 21.7 cm and 0.22 m/s at L = 14.1 cm. [Pg.254]

Immersion Corrosion—Accelerated Tests To simulate service of components that will be immersed in fluids, ASTM G 31 should be followed. This standard includes many precautions relating to how laboratory testing environments may differ from actual service. Issues such as immersion solution composition, temperature, aeration, velocity, and volume must be addressed thoroughly before the design of the test can be considered complete. For tests involving corrosion in water, two ASTM D 2688 and ASTM D 2776 should be referenced, which determine corrosivity by weight loss and electrical methods, respectively. [Pg.529]

Part of the testing philosophy involves whether the test is intended to reproduce a certain environment accurately or whether it is more advisable to use a corrosive environment that represents a worst-case situation. In either case, the corrosion investigator must do everything possible to make the test reproducible by exercising explicit control over environmental factors such as concentration of reactants and contaminants, solution pH, temperature, aeration, velocity, impingement, and bacteriological effects [19]. [Pg.463]

Until recently most industrial scale, and even bench scale, bioreactors of this type were agitated by a set of Rushton turbines having about one-thind the diameter of the bioreactor (43) (Fig. 3). In this system, the air enters into the lower agitator and is dispersed from the back of the impeller blades by gas-fiUed or ventilated cavities (44). The presence of these cavities causes the power drawn by the agitator, ie, the power requited to drive it through the broth, to fall and this has important consequences for the performance of the bioreactor with respect to aeration (35). k a has been related to the power per unit volume, P/ U, in W/m and to the superficial air velocity, in m/s (20), where is the air flow rate per cross-sectional area of bioreactor. This relationship in water is... [Pg.334]

Horizontally Mixing Aspirator Aerators. An aerator using a horizontally mixing aspirator has a marine propeller, submerged under water, attached to a soHd or a hoUow shaft. The other end of the shaft is out of the water and attached to an electric motor. When the propeller is rotated at high velocity, at either 1800 or 3600 rpm, a pressure drop develops around the propeller. Air is then aspirated under the water and mixed with the water, and moved out. This type of aerator, shown ia Figure 3g, is very efficient ia mixing wastewater. [Pg.342]

Group B soHds have higher minimum fluidization velocities than Group A soHds. For best results for Group B soHds flowing ia standpipes, standpipe aeration should be added at the bottom of the standpipe, not uniformly along the standpipe. [Pg.82]

Fig. 4. Galvanic series in flowing seawater. Certain alloys may become more active in low velocity or poorly aerated seawater and the potentials exhibited... Fig. 4. Galvanic series in flowing seawater. Certain alloys may become more active in low velocity or poorly aerated seawater and the potentials exhibited...
Gravity Settlers Gravity can act to remove larger droplets. Set-thng or disengaging space above aerated or boiling liquids in a tank or spray zone in a tower can be very useful. If gas velocity is kept low, all particles with terminal settling velocities (see Sec. 6) above the gas... [Pg.1429]

A subsequent patent, U.S. Patent 2,828,246 described a commercial process for bacitracin production. A 1,230 gallon portion of a medium containing 10% soybean oil meal, 2.50% starch and 0.50% calcium carbonate having a pH of 7.0 was inoculated with a culture of bacitracin-producing bacteria of the Bacillus subtilis group and the inoculated medium incubated for a period of 24 hours with aeration such that the superficial air velocity was 12.1. An assay of the nutrient medium following the fermentation revealed a yield of bacitracin amounting to 323 units/ml. This was more than twice the yields previously obtained. [Pg.126]

Use velocity of aerated mass same as for cleair liquid. Rh = hydraulic radius of the aerated mass for cross-flow, ft cross section... [Pg.180]

The relationship between f and Reft is given in Figure 8-127 and is recommended for design purposes. The velocity of the aerated mass is the Scime as for the clear liquid. [Pg.180]

Va = vapor velocity based on active area, ft/sec P = aeration factor, dimensionless. Figure 8-126... [Pg.182]

Vh = vapor velocity through valve holes, ft/sec P = tray aeration factor, dimensionless AP = tray pressure drop, in. liquid pvm = valve metal density, tj = tray deck thickness, in. [Pg.208]

A striking example of the interaction of solution velocity and concentration is given by Zembura who found that for copper in aerated 0-1 N H2SO4, the controlling process was the oxygen reduction reaction and that up to 50°C, the slow step is the activation process for that reaction. At 75 C the process is now controlled by diffiision, and increasing solution velocity has a large effect on the corrosion rate (Fig. 2.5), but little effect at temperatures below 50 C. This study shows how unwise it is to separate these various... [Pg.322]

In static air-free sea water the potential of iron or steel reaches a steady-statevalueof —0-75 V (v5. S.C.E., = 0-246 V) which should be compared with the more noble potential of —0-61 V observed under conditions of high velocity and aeration (Table 2.16). This potential of —0-75 V for iron in sea water is important in the practice of cathodic protection. [Pg.368]


See other pages where Aeration velocity is mentioned: [Pg.219]    [Pg.254]    [Pg.1014]    [Pg.501]    [Pg.749]    [Pg.535]    [Pg.67]    [Pg.68]    [Pg.78]    [Pg.154]    [Pg.579]    [Pg.798]    [Pg.219]    [Pg.254]    [Pg.1014]    [Pg.501]    [Pg.749]    [Pg.535]    [Pg.67]    [Pg.68]    [Pg.78]    [Pg.154]    [Pg.579]    [Pg.798]    [Pg.339]    [Pg.12]    [Pg.72]    [Pg.264]    [Pg.431]    [Pg.169]    [Pg.169]    [Pg.1380]    [Pg.1380]    [Pg.1424]    [Pg.2139]    [Pg.2423]    [Pg.104]    [Pg.119]    [Pg.124]    [Pg.118]    [Pg.261]    [Pg.330]    [Pg.993]    [Pg.882]    [Pg.1339]    [Pg.356]   
See also in sourсe #XX -- [ Pg.254 ]




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