Condensers design

I eon—Helium Separation and Purification. As indicated eadier, neon, heHum, and hydrogen do not Hquefy in the high pressure (nitrogen) column because these condense at much lower temperatures than nitrogen. As withdrawn, the noncondensable stream has a neon—helium content that varies 1—12% in nitrogen, depending on the rate of withdrawal and elements of condenser design and plant operation. 

It is common that compressor manufacturers provide data for the ratio of the heat rejected at the condenser to the refrigeration capacity as shown in Fig. 11-89. The solid line represents data for the open compressors while the dotted hne represents the hermetic and accessible compresors. The difference between sohd and dotted line is due to all losses (mechanical and elec trical in the electrical motor). Condenser design is based on the value ... 

The condenser design, surface area, and condenser cooling water quantity should be based on the highest cooling water temperature likely to be encountered, if the inlet cooling water temperature becomes hotter then the design, the primaiy booster (ejector) may cease functioning because of the increase in condenser pressure. 

Figure 1. Baffling and inlet bathtub are shown in this typical vacuum condenser design.

Braun, M., and Renz, U., Investigation of Multicomponent Diffusion Models in Turbulent Flow, Procc. Engineering Foundation Conf. on Condensation and Condenser Design, pp81- 92, 1993. 

Devore has presented useful charts for solving a multi-tuhe condenser design as shown in Figures 10-68,10-69, and 10-70. Figure 10-71 is useful for condensing steam. The charts all follow Nusselt s basic presentation however, a correction for turbulence of the film and other deviations is included. 

Cooler Condenser Design Lb-Water Program No. 710402 Water Rate Tube Modified Colbiu-n-Hougen, Bras Method Design Calc, for Sec. Coolers—Water Sat d at 110°F TL-in. Cooling Water Pass No. 2 In. °F 48.00 Lb-Gas, Gas Rate HLI, Water 8c Tube Acc-F, Program Tube 92.30 lb hr tube 480.00 Overall Coeff. Accmacy. 10 I.D. Controlled to 0.1 F Pl-Atm, Press, of Sys Gas in Top I.OOO ... 

Standiford, F. C., Effect of Non-Condensables on Condenser Design and Heat Transfer, Chem. Eng. Prog, July (1979) p. 59. 

Condenser design usually calls for thin-walled tubing with high thermal conductivity characteristics plus a high degree of resistance to biofouling and the many forms of corrosion that may occur. (These forms include crevice and pitting corrosion, biocorrosion, and erosion-corrosion). 

The greatest heat load will occur if all the oxidation occurs in the cooler-condenser (i.e. none in the WHB) which gives the worst condition for the cooler-condenser design. 

Unit 2, Condenser. Most of the alcohol will condense as its boiling point is 82°C. Assume 90 per cent condensed, 0 421 = 0.9 (liquid out) and 0 321 =0.1 (vapour out). The actual amounts will depend on the condenser design. 

The basic equations for filmwise condensation were derived by Nusselt (1916), and his equations form the basis for practical condenser design. The basic Nusselt equations are derived in Volume 1, Chapter 9. In the Nusselt model of condensation laminar flow is assumed in the film, and heat transfer is assumed to take place entirely by conduction through the film. In practical condensers the Nusselt model will strictly only apply at low liquid and vapour rates, and where the flowing condensate film is undisturbed. Turbulence can be induced in the liquid film at high liquid rates, and by shear at high vapour rates. This will generally increase the rate of heat transfer over that predicted using the Nusselt model. The effect of vapour shear and film turbulence are discussed in Volume 1, Chapter 9, see also Butterworth (1978) and Taborek (1974). 

Developments in the theory of condensation and their application in condenser design are reviewed by Owen and Lee (1983). 

Above a Reynolds number of around 2000, the condensate film becomes turbulent. The effect of turbulence in the condensate film was investigated by Colburn (1934) and Colburn s results are generally used for condenser design, Figure 12.43. Equation 12.51 is also shown on Figure 12.43. The Prandtl number for the condensate film is given by ... 

Figure 12.43 can be used to estimate condensate film coefficients in the absence of appreciable vapour shear. Horizontal and downward vertical vapour flow will increase the rate of heat transfer, and the use of Figure 12.43 will give conservative values for most practical condenser designs. 

For condenser design, the mean coefficient should be evaluated using the correlations for both annular and stratified flow and the higher value selected. 

The flow of water vapor should deviate as little as possible before the first condenser surface. The condenser design has to ensure that the water vapor is completely frozen and the remaining water vapor pressure is practically equal to the vapor pressure at the ice surface. This can only be achieved if the vapor passes over several condenser surfaces in series. 

The condenser design and surface can handle the vapor flow during main drying of this test. The possible low temperatures could be needed during secondary drying. 

In order to concentrate a solution the solvent is distilled through a downward condenser . For this purpose various forms of coil condenser are more convenient than the Liebig pattern. For working under reflux such coil condensers are less suitable because of the layers of liquid which form in the coil between the vapour and the external atmosphere. A condenser designed by Dimroth has proved suitable for both types of work. In it the cooling water passes through the coil (Fig. 1). In order to prevent condensation of water vapour on the coil it is advisable to fix a calcium chloride tube into the upper opening of the condenser. 

High intensity, microwave powered emission sources have recently been developed that are reported to provide substantially higher DUV output than classical electrode discharge mercury lamps 76). These sources suffer from self-absorption of the intense 254 nm emission but have a relatively high output in a band between 240 and 280 nm. They are extended sources of finite size rather than point sources, and they must also be an integral part of a tuned, resonant microwave cavity. Consequently, extensive condenser design work would be required in order to utilize the microwave powered sources in projection printers. 

The function of the reflux drum in a flooded condenser design is to... 

Fig. 1.90.2. Scheme of the condenser design in plant PI 1 in Table 1.12.6. 1, Condenser wall 2, condenser coil 3, suction tube of vacuum pump 4, water drain 5, connection to drying chamber 6, valve with seal in closed position 7 valve in open position... 

More elaborate means have been described for removing the acetone by distillation with relatively little isopropyl alcohol. These include various columns such as a Vigreux13 or a modified Widmer column.10 They are to be recommended when the aldehyde or ketone boils Within 50° of isopropyl alcohol, but are unnecessary under other circumstances. A reflux condenser maintained at constant temperature by boiling methanol has been suggested.6 More convenient than this is the simple but effective partial condenser designed by Hahn.49 An easily constructed modification is illustrated in Fig. 3 (adapted from Organic Syntheses).60 The partial condenser is attached directly to the round-bottomed flask, and ethanol is placed in the inner condensing tube. The... 

Smith, M. Effects of Condenser Design upon Boiler Feedwater Essergy Costs in Power Plants. M.S. Thes., Ga. Tech, 1981. 

Smith, M. S., "Efforts of Condenser Design Upon Boiler Feedwater Essergy Costs in Power Plants," Master s Thesis, GA Inst, of Technology, Atlanta, GA (1981). 

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