Project ForgeChemical Reaction Engineering
Ideal Reactor Design
GATE 2013
Hard
Liquid reactant A decomposes as follows: A→R, rR=k1CA² (k1=0.5 m³/mol-s); A→S, rS=k2CA (k2=1 s⁻¹). An aqueous feed of composition CA0=30 mol/m³, CR0=2 mol/m³, and CS0=1 mol/m³ enters a CSTR in which the above reactions occur. Assume isothermal and steady state conditions. If the conversion of A is 80%, the concentration of R in the exit stream in mol/m³, to the nearest integer, is _____
20 mol/m³(± 1 accepted)
Explanation
CA=CA0(1−X)=30×0.2=6 mol/m³. A balance: CA0−CA=τ(k1CA²+k2CA) ⟹ 24=τ(0.5×36+1×6)=τ×24 ⟹ τ=1s. R balance: CR=CR0+τ·k1CA²=2+1×0.5×36=2+18=20 mol/m³.
Source: GATE CH 2013 (2013)
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