課程名稱︰化學反應工程
課程性質︰必修
課程教師︰吳記聖
開課學院：工學院
開課系所︰化工系
考試日期（年月日）︰102/3/27
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 :
1. (a)(10%) @ 1100K, n-nonane thermally cracks (breaks down into smaller
molecules) 20 times as rapid as @ 1000K. Find the activation
energy for the reaction,
(b)(10%) The rule of thumb that the rate if reaction doubles for a
10 degree of Celsius increase in temperature occurs only at
at a specific temperature for a given avtivation energy. Develop
a relationship between temperature and activation energy for which
the rule of thumb holds. Neglect any variation of concentration
with temperature.
2.(20%)The reaction, A --> B, is to be carried out isothermally in a continuous
flow reactor. The entering volumetric flow rate v0 is 10 dm^3/hr. The flow
rate is constant (i.e. liquid). Calculate both the CSTR and PFR reactor
volume necessary to consume 99% of A (i.e. Ca = 0.01 Ca0) when entering
molar flow rate Fa0 is 5 mol/hr. Assume the reaction rate -r is:
(a) -r = k, k = 0.005 mol/hr-dm^3
(b) -r = kCa, k = 0.0001 1/s
(c) -r = kCa^2, k = 0.3 dm^3/mol-hr
3.(20%) For an irreversible gas-phase reaction, A --> 2B. The following
correlation was determined from the laboratory data (the initial
concentration of A is 0.2 mol/dm^3).
For X<= 0.5: 10^(-8)/-r = 3.0 m^3-s/mol
For X>= 0.5: 10^(-8)/-r = 3.0 + 10(X-0.5) m^3-s/mol
(a) Over what range of conversions are the PFR and CSTR volumes
identical?
(b) What conversion will be achieved in a CSTR that has volume of
90 dm^3?
(c) What PFR volume is necessary to achieve 70% conversion?
4. Choose the answer and explain.
(a)(5%) An irreversible, liquid-phase, second order reaction,
A --> products, proceeds ti 50% conversion in a PFR operating
isothermally, isobaricallym and at steady state. What
conversion would be obtained of the PFR operated at the half
the original pressure (with else unchanged)?
(1) >50% (2)<50% (3)50% (4) insufficient information to determine
(b)(5%)An irreversible, gas-phase, second order reaction,
A --> products, proceeds ti 50% conversion in a PFR operating
isothermally, isobaricallym and at steady state. What
conversion would be obtained of the PFR operated at the half
the original pressure (with else unchanged)?
(1) >50% (2)<50% (3)50% (4) insufficient information to determine
(c)(10%) The rate constant for an irreversible, heterogeneous catalyzed
gas-phase, second order reaction, A --> products, was
determined to be 0.234 from the experiments. The person
analyzed the data failed to consider large pressire drop. If
the pressure drop were properly accounted for, the rate would
be:
(1) >0.234 (2) <0.234 (3) 0.234 (4) insufficient information
5.(20%) The gas-phase irreversible first order reaction, A --> 3B, is carried
out in a PFR, where the feed is equal molar in A and inerts. The
conversion under these circumstances is 60%. The exut from the PFR is
fed to a CSTR of the same volume, and carried out under identical
conditions (i.e. temperature and pressure). What is the conversion
exiting the CSTR?
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Gas constant: R= 8314 Pa-dm^3/mol-K or 82.06*10^(-3) dm^3-bar/mol-K
Design equation:
Batch: Na0*(dX/dt) = -rV
CSTR : V=Fa0(Xout-Xin)/(-r)exit
PFR : Fa0(dX/dV)=-r
integral fomula:
S(1+ax)/(1-x)dx = (1+a)*ln(1/(1-x))-ax
S(1+ax)/(1-x)^2 dx = (1+a)*x/(1-x)-a*ln(1/(1-x))
total 100 points
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