Evaporation-condensation generators

Figure 12.4 Evaporation-condensation generator for the synthesis of ultrafine metal particles. The cylindrical glass chamber was 0.34 m in diameter and 0.45 m in height. Metal vapor from the alumina crucible mixes with the inert gas. The vapor nucleates particles grow by condensation and deposit on the cooled copper plate by thcrmophorcsis. (After Granqvisi and Buhrman. 1976.)...

Figure 12.5 Sizes of A1 and Cu particles produced in an evaporation-condensation generator. Median particle diameter increased with increasing inert gas pressure and atomic weight. (After Granqvist and Buhrman, 1976.)...

Aerosol Reactors Commercial and Pilot Scale 332 Flame Reactors 332 Pyrolysis Reactors 334 Electron-Beam Dry Scrithhirif 335 Evaporation-Condensation Generators 336 The Collision-Coalescence Mechanism of Primary Particle Formation 338... 

Both evaporation/condensation and nebulization equipments have been employed to generate droplets of reactive organic monomers, which could undergo the polymerization to powders when exposed to an initiator vapor. 

Zinc dust is produced from primary or secondary zinc metal by evaporation. The generated zinc vapor is condensed under controlled conditions under exclusion of air followed by sieving processes in order to obtain different particle size fractions [5.105]. The particle sizes of zinc dust are normally in the range 2 to 8 pm [5.105]. A product classed as fine quality shows a typical particle size of 3 pm whereas standard quality has particle size 8 pm [5.105]. 

Desalination, A special case of distillation is water desalination. In places where energy is abundant but fresh water is not, eg, the Arabian Peninsula, water may be produced from seawater in flash evaporators. Low pressure turbine steam is extracted to provide heat for the evaporators. Condensed steam is returned to the cycle. Such units may be particulady prone to corrosion by salts. Sizes vary, but a plant scheduled for completion in 1996 had six units and a total capacity of 345,600 m /d. Power generation was expected to be 17,500 MW (36). 

Figure 1 Schematic of evaporation-condensation method of aerosol generation.

E-C, evaporation-condensation N, nebulizer EC, electrostatic classifier VO, vibrating orifice SD, spinning disc FD, fluidized bed RB, rotating brush WDF, Wright dust feeder NBS, NBS dust generator. Values of parameters given are from specifications listed by TSI, Inc., and BGI, Inc. Stability data are from the references. A density of / g/m3 is assumed for the mass concentration values. 

J. G. Collier, Nuclear Steam Generators and Waste Heat Boilers, in Boilers, Evaporators Condensers, S. Kakag (ed.), pp. 471-519, Wiley, New York, 1991. 

Since 2003, RO-based unit operation to remove the radionuclides C Cs, ° Ru, U, Pu) from delay tank is continued, and the performance of the system was found to be promising [49-51]. The final discharge of low-level active waste (i.e., a mixture of evaporator condensate, ADU filtrate, and waste generated from personnel contamination [like hand washing to remove contamination from hand]) is carried out from the delay tank, which temporarily holds low-active waste. We thus evaluated RO for the removal of alpha activity, beta activity, nitrates, and total dissolved salts (TDSs) from delay tank water at the pilot plant. The delay tank water composition is given in Table 26.4. The specification of the membrane module, which was supplied by the Desalination Division of the BARC (Mumbai), is listed in Table 26.5. The module was... 

Figure 11.19 The shapes of micro-heat pipes.The capillary action to move the liquid from the condenser to the evaporator is generated in the corners.

Figure 10.12 Diagram comparing Cd and Zn isotope compositions for different classes of carbonaceous and ordinary chondrites. The Cd and Zn isotope ratio data are shown in 8-notation to denote isotopic variation in Cd/ °Cd and Zn/ Zn, respectively, relative to a terrestrial standard reference material in permil. For both Cd and Zn, pronounced isotope fractionation is apparent for the ordinary chondrites (and particularly unequilibrated ordinary chondrites of petrological type 3), whereas such effects are much more limited for the carbonaceous chondrites. This suggests that nebular processes only generate small Zn and Cd isotope fractionations, whereas large isotope effects are produced as a result of partial evaporation/condensation during parent body metamorphism [134]. Data from [38, 105, 127, 134).

A solution of sulfur trioxide [7446-11-9] dissolved in chlorosulfonic acid [7990-94-5] CISO H, has been used as a smoke (U.S. designation FS) but it is not a U.S. standard agent (see Chlorosulfuric acid Sulfuric acid and sulfur trioxide). When FS is atomized in air, the sulfur trioxide evaporates from the small droplets and reacts with atmospheric moisture to form sulfuric acid vapor. This vapor condenses into minute droplets that form a dense white cloud. FS produces its effect almost instantaneously upon mechanical atomization into the atmosphere, except at very low temperatures. At such temperatures, the small amount of moisture normally present in the atmosphere, requires that FS be thermally generated with the addition of steam to be effective. FS can be used as a fill for artillery and mortar shells and bombs and can be effectively dispersed from low performance aircraft spray tanks. FS is both corrosive and toxic in the presence of moisture, which imposes limitations on its storage, handling, and use. 

These compounds are stable only under basic conditions and must be held at high pH if stored for considerable periods of time. In Step 2, these methylolureas further react under acidic conditions with urea to form the various methylene urea oligomers. Water generated from the condensation reaction is removed by evaporation when producing granular UE products. 

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