Chemical Reaction Engineering - 1 - Dec 2015
Chemical Engineering (Semester 5)
TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks. 1(a) What is Optimum Temperature propagation? Explain with respect to different types of reactors(10 marks) 1(b) Differentiate Elementary vs Non elementary Reaction?(3 marks) 1(c) Write down the performance equation for recycle reactor?(2 marks) 1(d) The activation energy of a bio molecular reaction is about 9150 cal/mol. How much faster is this reaction at 500K than at 400K(5 marks) 2(a) The reaction between CO and NO2 at low temperature proceeds with a rate
-rO2=k*[N O2]2 Suggest mechanism.(12 marks) 2(b) In case of a first reaction, show that the times required for 75% conversion is double the time required for 50% conversion in a batch reactor(8 marks) 3(a) Calculate the first order rate constant for the disappearance of A as per the gas phase reaction A →1.6 R if the volume of reaction mixture, starting with pure A, increases by 50% in 4 minutes. The total pressure of the system remains constant at 1.2 atm and the temperature is 25 deg C(8 marks) 3(b) The initial rate of the reaction 2A+2B →C+D is determined for different initial conditions, with the results listed in the following table:
|Run||[A]0M||[B]0M||Initial rate, M/s|
Find the rate law and rate constant for this reaction.(12 marks) 4 From steady state kinetic runs in a mixed flow reactor, we obtain the following data on the reaction A R.
Find the space time needed to treat a feed of CAD=100 mol/m3 to 80% conversion 1) in a plug flow reactor 2) in a mixed flow reactor.
|? sec||CAO mol/m3||CA mol/m3|
A⇒R A⇒S A⇒T
where rR=1, rS=2 CA, rT=CA2. R is the desired product and S & T are desired product, CAO=2 mol/m3, Determine the maximum concentration of desired product obtainable in mixed and plug flow reactor(20 marks) 6 A first order liquid phase reaction is carried out in an ideal CSTR. The concentration of the reactant in the feed is 3 Kmol/m3 and the volumetric flow rate is 60 × 10-6 m3/sec. The density and specific heat of the reaction mixture are constant at 1000 kg/m3 and 4.19 KJ/kg.K respectively. The reactor volume is 18 × 10-3m3. There is no product in the feed stream and reactor operates adiabatically. The heat and rate of reaction are
Hr =-2.09 × 108 J/kmol, -rA=4.48 × 106 exp(-62800/RT) . CA kmol/m3sec
If the feed stream is 25°C, what are the steady state conversion and temperatures in the product stream ? Suggest with reasoning , the optimum temperature to achieve high conversion.(20 marks)