GATE CE 2019 Set 2 — Question 52
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Environmental Engineering → Drinking Water Treatment → Unit Processes
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Question
Consider the reactor shown in the figure. The flow rate through the reactor is . The concentrations (in ) of a compound in the influent and effluent are and , respectively. The compound is degraded in the reactor following the first order reaction. The mixing condition of the reactor can be varied such that the reactor becomes either a completely mixed flow reactor (CMFR) or a plug-flow reactor (PFR). The length of the reactor can be adjusted in these two mixing conditions to and while keeping the cross-section of the reactor constant. Assuming steady state and for , the value of (round off to 2 decimal places) is _______
Correct answer
1.1 to 1.15
Solution
For a first-order reaction ():
Rounding to two decimal places, the ratio is .
1.In a CMFR:
Given :2.In a PFR:
Given :3.Ratio of lengths:
Since and are constant:Rounding to two decimal places, the ratio is .
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