Additional Homework Problems

CDP6-29_B

Sergeant Nigel Ambercromby Scoundrels Incorporated, a small R&D company has developed a laboratory scale process for the elementary, solid-catalyzed-gas-phase reaction A + B C + D (names coded for proprietary reasons). The feed is equal molar in A and B with an entering molar flow rate of A of 25 mol/min and the volumetric feed is 50 dm³/min. Engineers at Scoundrels calculated that an industrial scale packed bed reactor with 500 kg of a very rare and expensive metal catalyst will yield a 66% conversion when run at 32 °C and a feed pressure of 25 atm. At these conditions the specific reaction rate is 0.4 dm³/mol/min/kgcat. Scoundrels sells this process and catalyst to Clueless Chemicals who then manufactured the packed bed. When Clueless put the process onstream at the specifications provided by Scoundrels, they could only achieve 60% conversion with 500kg catalyst. Unfortunately the reaction was carried out at 31.5 °C rather than 32 ° C. The corresponding 2160 mol/day of lost product made the process uneconomical. Scoundrels, Inc. say that they can guarantee 66% conversion if Clueless will purchase 500 more kg of catalyst at one and a half times the original cost. As a result Clueless contacted Sgt. Ambercromby from Scotland Yard (on loan to the L.A.P.D.) about possible industrial fraud. What are the first three questions Sergeant Ambercromby asks? What are potential causes for this lost conversion (support with calculations)? What do you think Sgt. Ambercromby suggests to rectify the situation (with Dan Dixon, Reaction Engineering Alumni W'97).

[3rd Ed. P4-9]