Checks Prior to Performance Testing

Good preparation alone is not sufficient to eliminate bottlenecks or unreliable data during the test. It is just as important to check and troubleshoot for bottlenecks and sources of unreliable data. The following considerations are important and are based on the author s experience supplemented by Refs. 2, 61, 133, 239, and 268. 

Using the preliminary test run, perform material balances on the unit and each column Ensure that these close within 5 percent. Do not proceed with the performance test if the closure is worse than 10 percent (118). Leaking valves and exchanger tubes will affect the material balance, and these leaks need to be identified prior to the final test. Meters have happened to read incorrectly even at times when the instrument people were sure they were 

Focus attention on flow measurements of streams close to their bubble point or dew point. Flsishing of liquid or condensation of vapor can lead to major errors. Investigate any noisy or heavily dampened flow meter signals. This may indicate unexpected fl ishing or condensation. 

Whenever practicable, cross check the material balance against direct volume or weight measurements (e.g., from product tank levels). Also, ensure that density corrections are applied for all flow meter readings correction equations are described elsewhere 

Carry out an energy balance An incorrect reflux meter will not show up in the material balance. Ensure closure is similar to the material balance. 

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