(107g) Methods for Obtaining Detailed Process Knowledge about Distillation Operations

For distillation and separation processes Chemical Engineers have historically relied upon plant process measurements such as flow rates, temperatures, and pressures and model or simulation results for data with which to solve troubleshooting or re-design problems. An array of on-line diagnostic services are available that can provide additional data offering real-time information on how pieces of process equipment are actually operating.

The most common application is gamma scanning. This test is primarily applied, but not necessarily limited to, distillation or separation columns. Gamma scans provide a density profile of the internal process of operating distillation columns and other process vessels. The density profile can be used to diagnose the hydraulic operating conditions of mass transfer devices such as damage to internals, flooding, degree of entrainment or weeping, liquid levels on trays and distributors, liquid distribution through packed beds, etc. The presenter will show case studies where scanning revealed vital process information that helped solve an operating problem, or helped make a revamp/re-design successful.

Additional derivatives from gamma scanning, CAT-scans and RapidScan, will be demonstrated. The CAT-Scan technique is a specialized horizontal gamma scan used to generate a topographic profile of the internal cross-sectional density of process equipment. This profile is useful for the detailed study of liquid flow distribution through packed columns as well as having applications beyond distillation columns. RapidScan is a new hardware system that allows for extremely accurate and repeatable gamma scan data acquisition in cases where comparison of historical data is important.

Radioactive tracers are used on operating processes to acquire real-world measurements of process variables that otherwise could only be calculated or estimated. Process variables that can be directly measured with radioactive tracers include flow rates, flow distribution, residence times, mixing characteristics, etc. Case studies of tracer applications applied specifically to distillation operations such as entrainment studies and leak tests will be discussed.