Inspection of process piping is becoming increasingly important as assets are getting older and running longer than their initial design constraints. The decision to rerate, repair or replace is an important safety and financial decision. With the potential for massive consequences if the incorrect decision is made, it is imperative many factors are considered. A fine balance must be struck between acquiring data as accurately and precisely as possible, while also minimizing downtime and the financial impact associated with taking equipment offline for extended periods of time. Cokebusters combats both of these issues by deploying its patented inline inspection tool, or "smartpig," as part of the company's combined service.
The unique combined service offered by Cokebusters sees mechanical decoking and smartpigging take place as part of the same service. Decoking operators and inspectors work together on-site 24/7, meaning no downtime between decoking of the process tubes and the inspection start. The Cokebusters smartpig is propelled by the same double-pumping unit as the decoking pigs, so no time losses are incurred to change equipment. As the smartpig is an inline inspection tool, it has the unique ability to accurately detect and quantify any remaining internal fouling after decoking procedures have been completed. Inspectors work closely with the decoking operators to identify and pinpoint areas of remaining fouling so additional decoking in any problem areas can be carried out.
Due to the smartpig running inline and utilizing the same double-pumping unit used for decoking, no access is required to the firebox, eliminating the need for scaffolding and confined space entry. A typical pass will take just 1-2 hours to inspect, and data is viewable within minutes of the smartpig being retrieved from the process tubing. A report on the condition of all tubes within the heater is issued in less than 24 hours of the inspection being completed -- all in less time than it would take to erect scaffold.
Utilizing smartpigging is becoming more commonplace within the petrochemical and energy industries due to the significant advantages offered over more traditional ultrasonic testing methods. Smartpigging offers more comprehensive coverage of the tube walls, with over 30,000 individual wall thickness measurements per meter of tubing; it is not uncommon to see over half a million individual wall thickness readings per tube -- significantly more than the three wall thickness measurements typically taken using handheld ultrasonic testing. The wall thickness measurements are combined with precise internal radii readings to build a more complete picture of tube condition, allowing for more detailed analysis to take place. This results in far more accurate fitness-for-service assessments and less conservative remaining life assessments, aiding in the decision to rerate, repair or replace.
The smartpig has the ability to detect the most common defects found within fired heaters, including diametric growth, internal and external wall loss, local and general wall loss, localized pitting and internal fouling. All defects can be accurately located both circumferentially and axially within the process tubing.
For more information, contact Ryan Caird at rcaird@cokebusters. com or visit www.cokebusters.com.
