CIA INSPECTION INC.

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CIA Inspection (CIAI) started the development of its coke drum inspection concept in 1991 and brought the first commercial system to market in November of 1994. Since that time, a second system has been built and brought on line.

The concept uses range imaging to capture the surface profile of the vessel wall. The equipment is designed to Class I, Division II requirements for work in explosive environments. The vessel does not have to be blinded before deploying the instrument into the drum. Therefore, the inspections don’t have to wait for a coker turnaround, but can be performed between coking cycles while the drum remains on-line.

High-resolution video is used to capture visual images inside the drum at the time as the laser scan. The video equipment meets ASME Section V, Article 9, T953 for Remote Visual Inspection capabilities.

The drill-cutting nozzle is removed to fit our drill stem extension. The instrument is typically installed from the bottom head access point where it is necessary to temporarily cover the chute while the instrument is being installed. The instrument head is raised and lowered in the drum using the existing, safety approved drill stem controlled by the site’s trained operator. CIAI’s processing software accommodates the off-center and movement issues of an in-service drill stem.

Once installed, the operation of the equipment is remote. CIAI technicians operate the instrument from an air-conditioned shelter located at ground level. Site inspectors can monitor the inspection activity from this same location. There is no need for technicians to work in the open air or under temporary cover at the top or bottom head of the drum. Local site restrictions, which limit human access to the structure during drum cutting of adjacent drums, are not a concern while performing the inspection. With no inspection equipment at the top head, steam and vapor leaks that often occur at the top head with on-line drums do not reduce the visibility of the system.

A complete laser and video inspection (including installation and removal of equipment) can be performed in less than 4 hours. Azimuth and elevation readings are permanently recorded on the video and are in direct correlation to the laser mapping. This ensures that the video information is gathered in the same time frame as the laser data. The direct cross-reference between the two makes it easier to confirm that an anomaly found in the laser data was not just a build-up of coke, for example.

Before starting each scan, the laser spot is pointed at a known and repeatable target (usually the bottom tangent weld) within the vessel to establish a reference point. This is essential when performing comparisons on year-over-year drum scans. Customer drawings are used to create weld seam overlays for each drum. The weld seam overlays can be amended in the case of repair areas. The ability to point the laser spot and set a reference to register the weld seam map with scanned profile data ensures the proper overlay of year-over-year drum profile data. CIAI’s laser scans do not rely on identifying subtle distortions in the drum surface to indicate weld seams. This approach is inaccurate at best and can break down when welds are either flush ground or coke covered.

The range camera can be tuned to accommodate the full range of vessel wall surface conditions. With any laser-based system, data can be missed on very reflective surfaces caused by water and/or oil on the vessel wall. These surface conditions tend to cause "missing data" in the laser collection system, which are minimized in our system due to its ability to be "tuned" on-line.

CIAI has performed over 500 inspections at sites throughout the world. The results have been assembled into a database to develop and track trends in various coke drum metallurgies.

CIAI-developed custom Drumview software allows the client to perform a number of investigations on the laser scan data. Export features allow the data to be easily "ported" to FEM models for Stress Modeling. A key feature of the software is it’s ability to accommodate multiple images on the screen at once and to allow multiple sections to be overlaid on subsequent scans to determine the nature and extent of the distortions as the drums "grow" and "age".

CIAI generates a detailed "Customer Report", before leaving the clients site, summarizing on both the laser profile and the video inspection as well as commenting on the overall condition of the drum relative to other drums in the industry. API certified inspectors review the results of the remote visual scan.

Send mail to jcameron@cia-inspection.com with questions or comments about this web site.
Last modified: September 27, 2005