課程名稱︰化學反應工程
課程性質︰必修
課程教師︰吳紀聖
開課學院：工學院
開課系所︰化工系
考試日期（年月日）︰103.04.01
考試時限（分鐘）：120
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
The First Midterm of Reaction Engineering (Class 2)
April 1, 2014 21:30~23:30 化工一
Close book
1. (20%) The gas-phase reaction, A → B + C is carried out isothermally
in a 20 dm^3 constant-colume batch reactor. Twenty moles of pure A is
initially placed in the reactor. The reactor is well mixed. (a) If the
reaction is first order: -rA = k CA, with k = 0.865 min^-1, calculate
the time necessary to reduce the number of moles of A in the reactor
to 0.2 mol. (b) If the reaction is second order: -rA = k CA^2 with
k = 2 dm^3/(mol-min), calculate the time necessary to consume 19.0 mol
of A. (c) If the temperature is 127 ℃, what is the initial total
pressure? What is the final total pressure assuming the reaction goes
to complete.
2. (30%) The exothermic reaction, A → B + C, was carried out
adiabatically and the following data recorded,
X (conversion) 0 0.2 0.4 0.5 0.6 0.8 0.9
-rA (mol/dm^3-min) 10 16.67 50 50 50 12.5 9.09
The entering molar flow rate of A was 300 mol/min. (a) What are the
PFR and CSTR columes necessary to achieve 40% conversion? (b) Over
what range of conversions, would the CSTR and PFR reactor colume be
identical? (c) What is the maximum conversion that can be achieved in
a 10.5 dm^3 CSTR?
3. (20%) The rate laws for the following reactions were obtained at low
temperatures. The reactions are highly exothermic and therefore
reversible at high temperatures. Suggest a rate law of each reaction
at high temperatures.
(a) A → B, -rA = k CA^2
(b) A + 2B → 2D, -rA = k CA^(1/2) CB
k PA PB
(c) A + B → C + D, -rA = -----------------------
(1 + KA PA + KB PB)^2
4. (20%) Set up a stoichiometric table for the following reaction and
express the concentration of each species in the reaction as a
function of conversion. Evaluate all constants (e.g. ε, δ, θ...).
Assume the reaction follows an elementary rate law, and write the
reaction rate solely as a function of conversion, i.e. -rA = f(x).
C2H6 → C2H4 + H2
Pure ethane enters the flow reactor at 7 bar and 1100K. How would you
rate equation change if the reaction were to be carried out in a
constant-colume batch reactor?
5. (20%) In 19th century, Henri Fabre found French ants busily bustled
about their business on the hot days but were rather sluggish on cool
days. The observed speeds are shown as followings,
Running speed, m/hr 150 160 230 295 370
Temperature, ℃ 13 16 22 24 28
What activation energy represents this change in bustliness?
------------------------------------------------------------------------------
Gas constant: R = 8314 Pa-dm^3/(mol-K) or 82.06 X 10^-3 dm^3-bar/(mol-K),
or 1.987 cal/mol-K
Batch: NA0 dX/dt = -rA V
CSTR: V = FA0 (Xout - Xin)/(-rA)out
PFR: FA0 dX/dV = -rA
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※ 編輯: guardinhell (140.112.250.1), 06/18/2014 16:27:13