Integral condensation

Integral condensation in which the liquid remains in equilibrium with the uncondensed vapour. The condensation curve can be determined using procedures similar to those for multicomponent flash distillation given in Chapter 11. This will be a relatively simple calculation for a binary mixture, but complex and tedious for mixtures of more than two components. 

It is normal practice to assume that integral condensation occurs. The conditions for integral condensation will be approached if condensation is carried out in one pass, so that the liquid and vapour follow the same path as in a vertical condenser with condensation inside or outside the tubes. In a horizontal shell-side condenser the condensate will tend to separate from the vapour. The mean temperature difference will be lower for differential condensation, and arrangements where liquid separation is likely to occur should generally be avoided for the condensation of mixed vapours. 

Where integral condensation can be considered to occur, the use of a corrected logarithmic mean temperature difference based on the terminal temperatures will generally give a conservative (safe) estimate of the mean temperature difference, and can be used in preliminary design calculations. 

The photomultiplier output is proportional to the transmission of the flame, yet concentration is proportional to absorbance. A logarithmic readout is preferred as being linear in absorbance This can be achieved by using an appropriate logarithmic amplifier, or when normalizing the output from the integrating condenser. 

Integral condensers are mounted directly upon the equipment in which vapors are produced which must be condensed. Integral condensers are frequently used in vacuum service because they eliminate large vapor lines and reflux pumps if reflux is required. Shell-and-tube, spiral plate, spiral tube, bayonet, and air-cooled condensers can be used as integral condensers. Condensing may occur either inside or outside of tubes. Figure 22-6 shows an... 

Integral condensers are not limited to vacuum service. They may be used when gravity drainage of condensate is required, when minimum system volume is desired, when expensive vapor piping is required, or when it is desireble to reduce structural steel requirements. 

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