Coke drums are utilized in the coker section of many oil refineries worldwide. Delayed cokers are generally constructed of large vertical vessels that can reach 80’ – 100’ (24m -30m) in height and between 7’ - 15’ (2m – 5m) in diameter. The coke drum is filled with tar that is cracked when it enters the coke drum. Once the drum is full of coke, a process which can take up to 18 hours, the feed supply (tar) is redirected to the next drum to be filled. The full drum is cooled, or quenched, with water. Longer quench times result in a decreased amount of stress on the drum’s metal components.
When the drum is sufficiently cooled, the coke is cut out by way of a waterjet delivered through a vertically-orientated drill stem. This explains why the coke drums are usually the tallest structures in the refinery. In fact, you can usually see a drilling derrick atop the drums. A mechanical flange must be removed from the top and bottom of the drum in order to cut the coke out and allow it to fall.
The constant thermal changes which occur between quench cycles ultimately lead to bulging and cracking throughout the drum. Quest Reliability’s proprietary LaserScan™/Video technology allows plants to more efficiently manage the life cycle of coke drums.
The LaserScan™ system combines a laser mapping technique with a visual inspection via video camera to detect anomalies. Before laser measurement technology, bulge detection and measurement required internal scaffolding and personnel entry into the drum. The internal visual inspection by our video camera equipment fulfills the compliance requirements for internal inspection. Cracking detected within welds or base material can be further examined utilizing Automated Ultrasonic Testing to quantify the extent of crack depth.
Features
- Repeatable inspection based on centered cable system
- Flexibility to inspect horizontally-oriented vessels (computer compensation of centering cable deflection)
- Hi-resolution /- 0.125" (3mm)
- Independent of owner/operator assistance
- Easy-to-use LaserView™ software provided with every inspection at no additional cost
Benefits
- Detects bulging and determines length, depth and width
- Detects the location of internal cracking and cladding damage
- Eliminates the need for internal drum scaffolding and grid mapping manpower
- Provides a baseline, repeatable scan of the vessels for future comparison
- Pre-turnaround inspection improvement of planning
- Meets requirements of NFPA Class 1 Div 2
- No blinding required
- Supports Finite Element Analysis (FEA)
- Economical, accurate, expedient
Applications
- Coke drums
- Pressure vessels
- Brick or refractory-lined vessels
Additional Information
For further information about LaserScan™ please contact us.