(64b) On-Line Troubleshooting Techniques for Packed Distillation

Pless, L., Tracerco

Mass transfer efficiency of distillation or separation columns with packing is very sensitive to the quality of liquid/vapor distribution. Being able to confirm suspicions of liquid/vapor mal-distribution and identifying the cause while troubleshooting the operation of packed columns is extremely advantageous. The opportunity to accomplish this while the equipment is on-stream so plans for remediation can be made without panic is even more beneficial.

There is a wide range of on-line diagnostic services available that can provide critical data offering real-time information on how packed distillation towers are actually hydraulically operating. The most common application is gamma scanning. 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 hydraulic operating conditions of mass transfer devices and determine issues 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 identify or solve an operating problem, or helped make a revamp/re-design successful on packed columns.

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. Applications involving tracers to study internal flow patterns will also be discussed.

A frank discussion of the benefits and limitations of these techniques will be presented, as well as areas where research and development is currently underway. As all past diagnostic technology innovations have started from a customer need, the presenter hopes to stimulate ideas from the audience that may result in the development of additional mass transfer diagnostic innovations.