Surface area effects in mass transfer or heterogeneous reactions

Surface area effects in mass transfer or heterogeneous reactions 

The rate of mass transfer aeross a phase boundary or interfaee ean be expressed by N=K.A(AC)  

SURFACE AREA EFEECTS IN MASS TRANSFER OR HETEROGENEOUS REACTIONS 5 1 

Drying, e.g. spray, drum, fluidized bed drying Powder mixing 

Emptying bags of powder, or fines from bag filters 

The rate of mass transfer across a phase boundary or interface can be expressed by N = K.A (AC) , 

Droplet generation by air pressure differential across the film, e.g. bursting of liquid film in bubbles, froth across bottle mouths and pipette tips 

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Interpreting the rate of an electrode reaction is often more complex than doing the same for a reaction occurring in solution or in the gas phase. The latter is called a homogeneous reaction, because it occurs everywhere within the medium at a uniform rate. In contrast, an electrode process is a heterogeneous reaction occurring only at the electrode-electrolyte interface. Its rate depends on mass transfer to the electrode and various surface effects, in addition to the usual kinetic variables. Since electrode reactions are heterogeneous, their reaction rates are usually described in units of mol/s per unit area that is. 

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