Quiz6key_Sp10

# Quiz6key_Sp10 - (a) Assume the reactor is an ideal CMFR CEE...

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CEE 320 Quiz #6 Environmental Engineering F 5 March 2010 CONTINUED ON REVERSE PLEASE WRITE YOUR NAME ON THE BACK Quiz #6 solution key (note: read the problem statement carefully - it is not identical to the one on your problem set) Useful information: For an equation of the form: dC dt = S LC , the solution is : C ( t ) = C o exp( Lt ) + S L [1 exp( Lt )] Question: A fluid flows through a reactor with mean residence time given by Θ . The system is illustrated below. The concentration of a contaminant species C in the fluid at the reactor inlet is 0 for all times t < t 1 . For all times t > t 1 , the concentration at the inlet is maintained at C in = C 1 . At t = 0, the tracer concentration within the reactor is zero. Within the reactor, the species undergoes first-order decay with rate constant k: C products R = kC For cases (a) and (b), sketch the time-dependent contaminant concentration at the outlet, C out (t), for t 0. The concentration and time scales should be properly and completely labeled with the same level of detail that we used in lecture.

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Unformatted text preview: (a) Assume the reactor is an ideal CMFR CEE 320 Quiz #6 Environmental Engineering F 5 March 2010 dCV dt = QC IN QC OUT kC OUT V Assume steady state dCV dt = At t &lt; t 1 , C IN = C out = At t &gt; t 1 , C IN = C 1 no longer at steady state dCV dt = QC IN QC OUT kC OUT V dC dt = Q V C IN Q V C OUT kC OUT = Q V C IN Q V + k C OUT S = Q V C IN and L = Q V + k Using the ODE solution. .. C OUT (t) = C exp Q V + k t + Q V C IN Q V + k 1 exp Q V + k t C = 0, C IN = C 1 C OUT (t) = Q V C IN Q V + k 1 exp Q V + k t (b) Assume the reactor is an ideal PFR dCV dt = kC OUT V Using ODE solution. .. C OUT (t) = C exp kt ( ) C OUT (t) = 0 for t &lt; t 1 + For t &gt; t 1 C OUT (t) = C 1 exp k ( )...
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## This note was uploaded on 05/04/2010 for the course CEE 320 taught by Professor Mcmahon during the Spring '10 term at Wisconsin.

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Quiz6key_Sp10 - (a) Assume the reactor is an ideal CMFR CEE...

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