私立中原大學八十八學年度博士班招生考試命題紙

所組別：

化學工程學系

科目：

動力學

考試時間：

06月09日第 1節

1. (30%)The catalytic oxidation of A,　　
   is believed to proceed by the following mechanism:

   quasi-equilibrium quasi-equilibrium 　　RDS quasi-equilibrium

   
   Knowing that the surface coverages of D and E are the same. Derive the rate expression of A.
   
   
2. (20%)多重選擇題 : The three curves below show the concentrations of a reacting species over spherical catalyst particle in three different conditions. For each of the three conditions, choose the correct answers and explain your answer briefly.

   i) external diffusion limited ii) pore diffusion limited iii) reaction limited iv)　ε<<1　　vi) ε<1 v) 　ε 1　　vii)ε>1 (ε represents the effectiveness factor)

   
   
   
3. (30%)One side of a flat aluminum wafer is reacted with nitrogen to grow a thin AIN layer ay constant temperature and pressure. The unreacted shrinking core model applies to the reaction. The original thickness of the aluminum wafer is L. The thickness of AIN layer is X. The total thickness of the AIN/A1 wafer is unchanged during the reaction. The molar density of A1 is ρ_B　and the following concentration profile of N₂ was found.

   	Flux of N2 across boundary layer = kg(Cag-Cas) Flux of N2 across AIN layer = De/x(CAo-CAi) Reaction rate based on unit surface area = ksCAi CA0 =HCAs where H is the Henry constant
   Show that the thickness of AIN can be expressed as X2+AX=Bt , and find the expressions for A and B.

   
   
   
4. (10%)Draw the residence time distributions of an ideal CSTR reactors. if a real CSTR is not well mixed, what changes will you see in its residence time distribution, relative to the prediction of the ideal CSTR?
   
   
5. (10%)Draw the residence time distribution of an ideal PFR reactor. Under what conditions will a liquid phase packed bed reactor approach the preditions of an ideal PFR?

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