Project ForgeChemical Reaction Engineering
Ideal Reactor Design
GATE 2019
Hard
First-order liquid reaction A→B (k=0.1/min) runs isothermally. Total feed CA0=1 mol/L, 100 L/min, splits between an ideal CSTR (exit CA=0.5 mol/L) and a PFR-1(40L)→PFR-2(60L) series train (exit CA=0.5 mol/L). The volume of the CSTR (Liters) is (rounded off to nearest integer)
856 L(± 5 accepted)
Explanation
PFR branch: τPFR=ln(CA0/CA)/k=ln2/0.1=6.93min=100L/QPFR ⟹ QPFR=14.43 L/min. So QCSTR=100−14.43=85.57 L/min. CSTR: τCSTR=(CA0−CA)/(kCA)=(0.5)/(0.05)=10min. V_CSTR=τCSTR×QCSTR=10×85.57=855.7 L.
Source: GATE CH 2019 (2019)
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