Air injectors

The off-gas may be mixed with fresh dilution air in air injectors or static mixers in order to reduce its temperature. Air injectors should preferably be of a cylindrical design and provided with baffles to intensify the mixing of the streams. Depending on the design temperature, the air injectors should be of welded steel construction, either refractory lined or of steel that is resistant to high temperatures. The dilution air may be filtered to prevent an extra load on the off-gas HEPA filters. 

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Gas Flow Rate (ml/mln) He H2 Air Injector Temperature Retention CC) Time Column Detector (min) ... 

The equipment is made of stainless steel, those parts that hold alkaline or neutral liquids may be made of carbon steel. The washing columns are equipped at the bottom with air injectors for emulsifying the nitro compounds in water. To avoid any hazards the plant is not equipped with mechanical stirrers. 

A cyclone outside the moving-bed catalytic colnmn serves to sort only catalyst particles of a desired size among the catalyst particles dropped to the lower portion. A nickel-molybdenum catalyst regenerator with an air injector serves to regenerate the catalyst transferred from the cyclone and the regenerated catalyst is then returned to the moving-bed catalytic cracker [29],... 

Fig. 3. Triple-effect evaporator. Cp Cjp Cjjj, condensate valnes Fp Fjj, Fjjj, feed valves J, Air Injector and Condenser P and T, pressnre and temperatnre for each effect.

This Downs type of mercury-controlled catalytic converter has been largely responsible for the expanded production of phthalic anhydride which has occurred since this country started making its own dye intermediates at the close of the war because of the operating economics made possible in the oxidation. A boiling mercury converter of approximately the same overall dimensions as the first-mentioned air-injector type has a capacity of from 1600 to 1800 pounds of phthalic anhydride per 24 hours and is so automatic in operation that a single operator can manage as many as eight of them. 

Figure 3.8 The directional distribution of the skewness factor with (J — air injector at 500 psia) and without (2 — normal jet) microjet injection Mj = 1.38.

The performance of an airlift can be derived from hydrostatic principles in terms of the submergence of the air injector below the liquid level in the feed tank (A,), the delivery height above this level (Ar), and the pressure and density of air at ambient atmospheric pressure (P and p ). The atmospheric pressure is expressed as an equivalent height hd of a liquid of density p. The following equation gives an estimate of the mass of air required per uni) mass of liquid (or slurry) ignoring frictional loases in the system ... 

Hydrogen-oxygen offgas explosions have occurred in some older boiling water reactors where no treatment of such gases was given. The explosions took place in various components from the condenser air injector downstream to the vent stack and... 

FIGURE 2.11. Schematic representation of the Photo-CREC Water-II Reactor (1) MR or BL lamp, (2) replaceable 3,2-cm-dianieter glass inner tube, (3) replaceable 5.6-cm-diameter glass inner tube, (4) fused-silica windows, (5) UV-opaque polyethylene outer cylinder, (6) stirred tank, (7) centrifugal pump, and (8) air injector, (Reprinted with permission from Ind. Eng. Chem. Res., 40(23), M. Salaices, B. Seiraiio and H.l. de Lasa, Photocatalytic conversion of organic pollutants Extinction coefficients and quantum efficiencies, 5455-5464. Copyright 2001 American Chemical Society). 

Turbulent mixing of flue gases and secondary combustion air through the use of high velocity tangential air injectors, internal air injectors, abrupt changes in gas flow directions, or refractory orifices, bafQes, internal injectors, and checker work in the gas flow passages. 

There is considerable information available in the hterature on the design of ejectors (steam jet ejectors, water jet pumps, air injectors, etc.) supported by extensive experimental data. Most of this information deals with its use as an evacuator and the focus is on ejector optimization for maximizing the gas pumping efficiency. The major advantage of the venturi loop reactor is its relatively very high mass transfer coefficient due to the excellent gas-liquid contact achieved in the ejector section. Therefore, the ejector section needs careful consideration to achieve this aim. The major mass transfer parameter is the volumetric liquid side mass transfer coefficient, k a. The variables that decide k a are (i) the effective gas-hquid interfacial area, a, that is related to the gas holdup, e. The gas induction rate and the shear field generated in the ejector determine the vine of and, consequently, the value of a. (ii) the trae liquid side mass transfer coefficient, k. The mass ratio of the secondary to primary fluid in turn decides both k and a. For the venturi loop reactor the volumetric induction efficiency parameter is more relevant. This definition has a built in energy... 

There are drawbacks however. In the first system in particular there is a considerable aerosol production and some stripping of aromatic HC. In dre second and third systems, basins 8 to 10 m deep can be designed which will still involve the use of air injectors, however (Dipair, Kentcs). In addition to the fact that the facilities are compact, there are two further advantages ... 

Possibility of using deep tanks (6 to 10 m) thanks to air injectors. 

Heat exchangers, condensers, and cooling towers Nuclear power Air injectors... 

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