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）︰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? ----------------------------------------------------------------------------- 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 -- 夜飲東坡醒復醉，歸來彷彿三更。家僮鼻息已雷鳴，敲門都不應，倚杖聽江聲。 長恨此身非我有，何時忘卻營營？夜闌風靜縠紋平，小舟從此逝，江海寄餘生。 --

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