Gamma Scanning Columns with Packed Beds

TowerScan wants to help you solve your packed bed troubleshooting challenges. Our "TowerScan" gamma scanning service provides you with the best method of finding out what is happening inside your column while it is still in operation – saving time and money.

When a packed bed column is scanned, the two most common scenarios are where a single scan is performed, or scans on a 2 x 2 grid as shown in the image above.

A single "TowerScan" on a packed bed column will determine:

• whether all the packed beds are present in the column
  
• if the beds have experienced any damage or settling of the packing
  
• the liquid level on chimney and collector trays
  
• if any of the beds have experienced flooding or fouling
  
• whether the demister pads and distributors are at their proper elevations

By performing and analyzing a full 2 x 2 grid scan, our engineers evaluate:

• the extent and location of liquid maldistributions within the packed beds
  
• if tower internals such as demister pads, distributors, trays, and the top of beds are level

In addition to using gamma scans as a troubleshooting tool, some companies make excellent use of the information to schedule shutdowns. In processes where they know the packing gradually becomes fouled, periodic scans monitor the progress of the fouling. They can then accurately schedule their turnarounds, as opposed to having to incur sudden, unexpected, and costly shutdowns. Examples of "before" and "after" scans performed on a tower are shown in Figure 2.

The initial scan (red) showed that the demister pad, distributor, packed bed, and chimney tray were at the proper elevations. The bed however had experienced severe fouling, especially in the bottom two thirds of the packing. The column was shut down and the packing replaced.

The scan taken after the turnaround (blue) exhibited a far more uniform bed density. Some higher densities were seen at the top and bottom of the bed due to the hold down plate and bed support, and part way down the bed due to external mechanical interference.

Call TowerScan today to find out how we can help you. Our staff have been scanning columns since 1989 and have the experience you need. Already the leader in quality and value, TowerScan will continue to be their customers first choice for column troubleshooting and process optimization.

TowerScan, P.O. Box 347, Corunna, ON N0N 1G0. Tel: 519-862-4302; Fax: 519-862-5437.