Multiple Reaction Conversion Notes

1 02 03 04 05 conversion x 06 07 che che 400

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Unformatted text preview: separated D Cost ($$$) ChE ChE 400 - Reactive Process Engineering Selectivity: Parallel Reactions 0.1 0.2 0.3 0.4 0.5 Conversion (X) 0.6 0.7 ChE ChE 400 - Reactive Process Engineering Parallel Reactions: Selectivity II L11-9 L11- D U A rD = kD CAd = k0,D exp{-ED/RT} CAd rU = kU CAu = k0,U exp{-EU/RT} CAu Differential S’ Selectivity: S’ = νD rD / (νD rD + νU rU) (S’)-1 = 1 + νU rU/νD rD (S’)-1 ~ νD/νU rU/rD = νDU k0U/k0D exp{-(EU-ED)/RT} CA(u-d) (dS’ ~ exp{-(ED-EU)/RT} CA(d-u) (I) d > u S’ increases with • PFR (BR) > CSTR • no dilution • high pressure (II) d < u S’ increases with • CSTR or PFR w/high recycle • dilution • low pressure (III) ED < EU S’ decreases with (IV) ED > EU S’ increases with ChE ChE 400 - Reactive Process Engineering Differential and Total S L11-10 L11- k1 Parallel reactions, different rctn orders A (Reactor) Selectivity: SD = A k2 D r1 = k1 CAd r2 = k2 CAu U Local selectivity: SD’= (or equivalently with Fj!) Hence we calculate ND: N D = SD . For V = const. FB 1 = =− FA0 − FAe FA0 − FAe SD = − C A0 1 − C Ae FAe ∫ S′ D dFA FA 0 C Ae ∫ S′ D dC A CA 0 total S ==integral average of local S total S integral average of local S ChE ChE 400 - Reactive Process Engineering PFR vs CSTR L11-11 L11- SD = − C A0 1 − C Ae C Ae ∫ S′ D dC A CA0 SD’= SD’ d <<uu d d >>uu d SD’ 1 1 CAe CA0 CA...
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This note was uploaded on 10/31/2013 for the course CHE E440 taught by Professor Baier during the Fall '13 term at Columbia.

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