Why Refinery Industries Should Consider Gamma Scanning Technique

Gamma scanning is primarily a nuclear inspection technique used to troubleshoot industrial types of equipment in petrochemical plants and oil refineries such as reactors and distillation columns. Did you know gamma scanning can address and fix any problems in your process tower safely and quickly in a way that other techniques can’t? It is one of the most effective non-invasive methods for diagnosing and solving production issues.

This technique features a sealed radiation source and a detector that moves along the equipment. The intensity readouts generate the density profile of the equipment. In large diameter refinery vacuum columns, gamma scanning is used to identify on-line problems in both tray columns and packed columns.

Columns with trays can be scanned to determine;

  1. The density and extent of aerated liquids
  2. The amount and spread of flooding, foaming, entrainment, or weeping
  3. The position of production bottlenecks
  4. The accumulation levels of liquid at the base of the tower
  5. The location of trays that are displaced or damaged

Packed columns can be scanned to determine;

  1. Whether beds have experienced fouling or liquid holdup
  2. Any settling of the packing
  3. If any damage has occurred with the beds
  4. Accurate readings for liquids on chimney and collector trays
  5. Whether all the packed beds are in the position
  6. Whether there are major issues in the liquid-vapor distribution

Pipe scanning can be done to;

  1. Find blockages
  2. Gauge flowing densities
  3. Pinpoint the location of liquid in vapor lines
  4. Locate coke, scale, or ice buildups
  5. Discover areas of lost refractory within a pipe
  6. Analyze catalyst fluidization

Benefits of Gamma scanning

  • Helps you avoid unexpected and unpleasant production delaysInspection gamma brings issues to light that may become problems in the future. An unscheduled shutdown can cost the company millions in lost production. Through the integration of Gamma scanning into your maintenance plan, you can schedule shutdown when it suits your production timeline thereby preventing impromptu shutdowns and disruptions.
  • Ensuring safe operations and keeping production on track: Gamma scanning offers a solution to identifying issues within the process columns. The technique evaluates the operating characteristics in the tower quickly and reliably. The tower scans take place un-intrusively with operations still ongoing within the process units.
  • Generation of valuable information: Inspections through Gamma scanning provide unique and valuable information that can’t be obtained via any other methods. Inspection gamma investigative tool optimizes troubleshooting to provide quality information on target problems, help in determining solutions, and schedule resources. The information aids in making informed decisions that in turn ensure the integrity of production and keep production revenue within expectations.
  • Helps in detecting issues in both strayed and packed towers: Various determinations such as damaged trays or packed columns are made upon analysis scan.


Regular monitoring of distillation columns and piping facilitates determining hydraulic features such as foaming rates and flood points. For overall tower hydraulics and packing performance, baseline tower scans can be initiated often. With the Gamma scanning technique, inspections can be done through any insulating and cladding material on either large or small diameter distillation columns.

Sanjit Dhabekar


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