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HOMETen Types of Home Problems

Homogeneous Examples


Type 9 Home Problem
Problems that promote discussion.

Worthless Chemical has been making tirene (B) from butalene (A) (both dark liquids) using a 12 ft3 CSTR followed by a 4.5 ft3 PFR. The entering flow rate is 100 mol/min of butalene (A). The feed is heated to 60 C before entering the CSTR. A conversion of 80% (Xi) is typically achieved using this arrangement.

One morning, the plant manager, Dr. Pakbed, arrived and found that the conversion had dropped to approximately 36% (Xii). After inspecting the reactors, the PFR was found to be working perfectly, but a dent was found in the CSTR that may have been caused by something like a fork-lift. He also noted that the CSTR, which normally makes a "woosh" sound was not as noisy as it had been the previous day.

The manager calls in four junior engineers (Jane, Steve, Bill, and you) to investigate the problem.





FAo = 100 mol/min

T = 60 C



    Xi = 0.8

    Xii = 0.36


A plot of the inverse of the reaction rate versus conversion is presented below:


I. Make a list of all the things that could cause the drop in conversion. Propose tests to confirm the explanations. Quantify the explanations with numerical calculations, where possible.

II. Dr. Pakbed tells you that in order to meet the production schedules down stream, he needs a conversion of a least 70%. Can this conversion be obtained without taking time to fix to the CSTR?


Solution to Homogeneous Problem #9


Other Homogeneous Problems
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CRE Thoughts Ten Types Homogeneous Example 9