Diagnose Flooding Columns Efficiently
SUMMARY
Using field pressure data, a refiner made a low-capital modification on a crude distillation column to increase throughput without a shutdown.
TEXT
Flooding of the crude distillation unit (CDU) adversely impacts a refinery’s profits. Such conditions force crude charge reductions, downgrading of product draws, etc. Consequently, the CDU operates under stress. Determining the root cause for the flooding is another obstacle that a refiner must overcome. Incorrect diagnosis of the flooding source can be equally as damaging as the root cause. Gathering valid field data is vital when understanding the dynamics occurring within the crude column. Proper interpretation of the data is also required to determine the best recourse to correct the problem.
In this case history, a crude column begins flooding. Severe upsets reduced crude throughput. Field pressure drop data are used to find the root cause for the flooding and operational upsets. With this information, the refiner installs a bypass online to override the column’s restriction and restore the column’s performance.
Tosco Refining Co., a division of Tosco Corp., owns and operates a large, highly integrated singletrain refinery at Belle Chasse, Louisiana. (Tosco purchased the Alliance Refinery on Sept. 8, 2000.) This facility’s CDU had been operating over six years since the last turnaround. In early 2000...