Project ForgeThe desired reaction D+E→F (rF=k1CD²CE^0.3) is accompanied by an undesired side reaction D+E→G (rG=k2CD^0.4CE^1.5). Four isothermal reactor schemes for equal molar feeds of D and E, all at the same conversion, are compared. The scheme giving the most favorable product distribution feeds:
- AD and E both to a single CSTR
- BD and E both together to the entrance of a PFR
- E distributed along the length of a PFR, D all at the entrance
- DD distributed along the length of a PFR, E all at the entrance
Explanation
F has a much higher order in CD (2 vs 0.4) and lower order in CE (0.3 vs 1.5) than G, so maximizing selectivity for F requires keeping CD high and CE low throughout. Feeding D all at once (staying high, only depleting via reaction) while distributing E gradually along a PFR (keeping it low throughout) achieves this.
Source: GATE CH 2019 (2019)
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