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）︰103.06.18
考試時限（分鐘）：110
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
The Final of Reaction Engineering (Class 2)
6/18/2014 10:20~12:10
Close book
1. The formation of propanol on a catalytic surface is believed to
proceed by the following mechanism. Assume surface reaction is rate
limiting step and derive a rate law.
O2 + 2S ←→ 2O‧S
C3H6 + O‧S → C3H5OH‧S (rate limiting)
C3H5OH‧S ←→ C3H5OH + S
2. A recent study of the CVD of silica from silane (SiH4) is believed to
proceed by the following irreversible two-step mechanism. This
mechanism is somewhat different in that while SiH4 is irreversibly
adsorbed, it is highly reactive. In fact, adsorbed SiH2 reacts as fast
as it is formed [i.e., r*SiH2‧S ~ 0, by PSSH], so that is can be
assumed to behave as an active intermediate.
SiH4 + S → SiH2‧S + H2
SiH2‧S → Si + H2
(a) Determine if this mechanism is consistent with the following data:
[hint: assign a rate-limiting step and derive a rate law, then check
it with data]
Deposition rate (mm/min) 0.25 0.50 0.75 0.80
Silane pressure (mtorr) 5 15 40 60
3. The acid-catalyzed irreversible liquid-phase reaction, A → B, is
carried out adiabatically in a CSTR. The reaction is second order in
A. The feed, which is equimolar in a solvent (S, which contains the
catalyst) and A, enters the reactor at a total columetric flow rate of
10 dm^3/min with the concentration of A being 4 mol/dm^3. The entering
temperature is 300 K. What CSTR reactor volume is necessary to achieve
80% conversion?
Additional information: ΔHRX(300K) = -3300 cal/mol-K, CpA = 15
cal/mol-K, CpB = 15 cal/mol-K, CpS = 18 cal/mol-K, k(300K) = 0.0005
dm^3/mol-min, Ea=15000 cal/mol.
4. The adiabatic equilibrium conversion for the reaction, A + B → C + D,
is carried out in a series of staged packed-bed reactors with
interstage cooling. The lowest temperature to which the reactant
stream may be cooled is 27℃. The feed is equal molar in A and B, and
each reactor is 100% efficiency in conversion. The feed enters at 27℃
and the reaction is carried out adiabatically. If four reactors and
three coolers are available, what conversion may be achieved? Use the
following information, ΔH°RX = -30 kcal/mol A, CpA = CpB = CpC = CpD
= 25 cal/mol-K, Ke(50℃) = 500000, FA0 = 10 mol A/min.
5. The first-order irreversible exothermic liquid-phase reaction, A → B,
is to be carried out in a jacketed CSTR (i.e., with coolant). Species
A and inert I are fed to the reactor in equimolar amounts. The molar
feed rate of A is 80 mol/min. What is the reactor temperature for a
feed temperature (T0) of 450K?
Additional information: ΔHRX = -7500 cal/mol, CpA = CpB = 25
cal/mol-K, Cp inert = 35 cal/mol-K, τ = 100 min, k = 0.0066 min^-1 at
350K, Ea = 41000 cal/mol, coolant temperature Ta = 300K, UA = 8000
cal/mol-K.
------------------------------------------------------------------------------
CSTR: V = FA0 (Xout - Xin)/(-rA)out
PFR: FA0 dX/dV = -rA
Σθi Cpi (T - T0)
Adiabatic flow reactor X = --------------------------------,
-[ΔH°RX(TR) + ΔCp (T - TR)]
X[-ΔH°RX(TR)] + Σθi Cpi T0 + X ΔCp TR
T = --------------------------------------------
Σθi Cpi + X ΔCp
G(T) = (-ΔH°RX)(-rA V/FA0) = (-ΔH°RX)(X)
R(T) = Cp0 (1 + κ)(T - Tc)
T0 FA0 Cp0 + UA Ta κTa + T0
Tc = -------------------- = -----------, where Cp0 = Σθi Cpi,
UA + Cp0 FA0 1 + κ
U A
κ = ---------
Cp0 FA0
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
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 140.112.250.1
※ 文章網址: http://www.ptt.cc/bbs/NTU-Exam/M.1403080011.A.6A6.html