The Effect of Intrapellet Mass Transfer on Observed Rate

11-9 The Effect of Intrapellet Mass Transfer on Observed Rate 

In Sec. 10-1 we saw that neglecting external resistances could lead to misleading conclusions about reaction order and activation energy. Similar errors may occur when intrapellet mass transfer is neglected. Consider the situation where 1 5. In this region intrapellet transport has a strong effecion the rate Fig. 11-7 shows, that 77 is less than about 0.2. From Eqs. (11-54) and (11-50) for a first-order reaction 

Using these expressions for rj in the equations for the rates for the whole pellet [for example, Eq. (11-44)], we obtain 

If the rate constants are expressed as Arrhenius functions... of temperature, k = then 

These equations give the correct influence of concentration and temperature when intrapellet dijffusion is important. 

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SECTION 11-9 THE EFFECT OF INTRAPELLET MASS TRANSFER ON OBSERVED RATE... 

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