Chapter 5, Problem 5.14P

The dehydration butanol of alumina is carried out over a silica-alumina catalyst at 680 K.

${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}\underset{\text{cat}}{\to }{\text{CH}}_{\text{3}}\text{CH}{\text{= CHCH}}_{\text{3}}\text{ +}{\text{H}}_{\text{2}}\text{O}$

The rate law is

$-r_{\text{B}u}^{\prime }=\frac{k{P}_{\text{B}u}}{{(1+K_{\text{B}u}{P}_{\text{B}u}\text{)}}^2}$

with k = 0.054 mol/gcat•h•atm and K_Bu = 0.32 atm⁻¹. Pure butanol enters a thin-tubed, packed-bed reactor at a molar flow rate of 50 kmol/hr and a pressure of 10 atm (1013•kPa).

1. (a) What PBR catalyst weight is necessary to achieve 80% conversion in the absence of pressure drop? Plot and analyze X, p, f (i.e., (υ/υ₀)) and reaction rate, −r′_A, as a function of catalyst weight.
2. (b) What “fluidized CSTR” catalyst weight is necessary to achieve 80% conversion?
3. (c) Repeat (a) when there is pressure drop, with the pressure-drop parameter α = 0.0006 kg⁻¹. Do you observe a maximum in the rate of reaction, and if so, why? What catalyst weight is necessary to achieve 70% conversion? Compare this weight with that for no pressure drop to achieve the same conversion.
4. (d) What generalizations can you make about this problem?
5. (e) Write a question for this problem that requires critical thinking and then explain why your question requires critical thinking. (Hint: See Preface Section I.2)