| (b) | Determine the minimum cost of the combination of the heat exchanger and reactor 2 to achieve an overall conversion of 95% (based on the feed to reactor 1). Air is to be used as the coolant and is available at 77°F and a rate of 100 mol /h. The cost of the reactor is |
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| This cost includes both the catalyst and reaction container costs. The cost of the heat exchanger is | |
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| (c) | Rather than using air as a coolant in the heat exchange, the feed stream to Reactor 1 is used. The feedstream enters the exchange at 600°F, is preheated to temperature T0, and is fed directly to Reactor 1. The stream then leaves Reactor 1 at temperature T1, again enters the air heat exchange (this time as the hot stream), exits the exchanger at T2, and enters Reactor 2. The weight of catalyst in Reactor 1 is equal to the weight of catalyst in Reactor 2. Determine the minimum cost of this reactor system (heat exchanger + Reactor 1 + Reactor 2) necessary to achieve an overall conversion of 92%. The cost functions are given by equations above. Reasonable first estimates of catalyst weight and T0 in each reactor are 100 lb and 910°F, respectively. |
[2nd Ed. P8-34 (b) and (c)]