Gamma Scanning should be discussed as a serious consideration in any pre-shutdown planning for oil and gas plants with distillation towers.
When shutting down your plant, or even part of it, you want to minimize your downtime, your costs and the accumulation of lost production when not operating. Gamma Scanning on your trayed and packed towers serves as part of a complete analysis before the plant comes down.
Gamma scanning is performed while the towers are operating and can be weeks or months in advance of your planned shutdown. The Gamma Scan is non-invasive and will have no effect on your process while providing valuable information to engineers, planners and operational personnel.
The Gamma Scan can identify damaged or missing trays, packing, demisters and distributors. It can locate and quantify flooding, fouling, foaming, entrainment and weeping which are often indicators of operational issues.
If the results from the Gamma Scan show satisfactory tower performance, no vessel entry may be required during the shutdown. This saves time, materials and personnel which significantly reduces your costs during the shutdown. With less maintenance, comes less scheduling and fewer people involved in higher safety sensitive activities. The scanning pays for itself many times over.
If the Gamma Scan identifies damage to internal components, the replacement equipment can be ordered in advance of the shutdown which saves the additional cost of rushed manufacture of these components. Without a scan, the operator may have to start back up with the damaged internals while waiting for replacements. A second shutdown once the internals arrive is then required significantly adding to the cost and incurring additional throughput loss from the affected vessels.
Recently, in a trayed tower, we identified severe fouling on the lower 5 trays during a pre-shutdown scan. Due to the process fluids in the tower, the fouling material was thought to be some kind of ashpaltene and a chemical wash was performed on the tower. The in-situ chemical wash cleaned the trays sufficiently and it was not necessary to enter the tower during the shutdown. The operator saved 2 days of lost production revenue as well as replacement tray costs on a rush order. Additional cost savings were recovered by reduced maintenance personnel and equipment.
A packed tower was scanned in a pre-shutdown plan which identified the top 20% of the packing showing a higher density than the remainder of the bed. The customer was able to order replacement for only the fouled packing material ahead of the shutdown. The required packing was replaced minimizing the downtime and cost to the customer.
Contact us today to find out more about how our scanning services can help.