Free flooded streams

In gas-cleaning installation buildings, often there are so-called free flooded streams (Idelchik, 1968). They originate, for example, at an entry of a stream from a gas pipeline in the apparatus of much larger cross section already filled with gas. Thus, between an inducted stream of a basin (aerosol) and a mix in the apparatus, there are difficult contacts, where the result is quite often expressed in not design fall of aerosol corpuscles. The specified phenomenon not always is desirable. For example, in the scrubber of full transpiration used as the air conditioner, but not as the dust precipitator, the bottom part turns to the dry dust-collecting chamber. 

Most column control schemes (see Sec. 16.5) use the composition (or temperature) controller to manipulate either the reflux or reboil, directly or indirectly. The stream which is not controlled is commonly "free, i.e., on flow control. This "free stream is usually manipulated during flood testing, while the stream on temperature control will be automatically adjusted to maintain product composition. For instance, if reflux rate is on temperature control and reboil rate is on flow control, flood testing is performed by raising the reboil rate. This warms up the control tray and increases condensation. The temperature controller will call for more reflux, and the column will reach new stable conditions with both reboil and reflux increased. 

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