Does your distillation simulation reflect the real world

The question ``Do you have a simulation?`` is asked during almost every troubleshooting investigation. A question equally important: ``Does your simulation reflect the real world?`` is raised far less frequently. To correctly answer the latter question, it is imperative that the simulation reflects the real world (i.e., plant data). Any mismatch provides a warning of a potential simulation deficiency. A previous paper described a case where a seemingly minor mismatch led to the discovery of a major simulation deficiency. Undiscovered, the deficiency would have led to a failed tower debottleneck. This paper expands on this previous theme, but focuses on column troubleshooting. A simulation that did not reflect the real world steered a troubleshooting investigation toward an incorrect diagnosis and into inadequate solutions. Once revised to reflect the real world, the same simulation proved invaluable for identifying the correct root cause and guiding the investigation toward the proper solution. An initial simulation of an aromatics fractionator revealed no cause for an operational instability apparent in the tower. Field testing of the tower, establishing correct energy balances, overcoming an analytical limitation, and finally, identifying a simulation trap, yielded information that led to revision of the initial simulation. The revised simulation readilymore » identified the cause of the tower instability.« less