NTU Number of Transfer Units

NTU (Number of Transfer Units) The NTU required for a given separation is closely related to the number of theoretical stages or plates required to carry out the same separation in a stagewise or plate-type apparatus. For equimolal counterdiffusion, such as in a binary distillation, the number of overall gas-phase transfer units Nog required for changing the composition of the vapor stream from y to t/2 is [Pg.61]

When diffusion is in one direction only, as in the absorption of a soluble component from an insoluble gas, [Pg.61]

When it is known that H0G varies appreciably within the tower, this term must be placed inside the integral in Eqs. (5-290) and (5-291) for accurate calculations of hT. For example, the packed-tower design equation in terms of the overall gas-phase mass-transfer coefficient for absorption would be expressed as follows [Pg.61]

In a similar way, liquid-phase mass-transfer rates may be defined by the relations [Pg.61]

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