The pioneer in using electromagnetic test methods, Friedrich Foerster, was the founder of INSTITUTE DR. FOERSTER. Today, FOERSTER has many subsidiaries and a multitude of representatives in all over the world, specialized in all kind of eddy current testing. Magnetische Pruefanlagen GmbH (MP) belongs to the Foerster Group and has been inspecting reformer tubes for more than 30 years with their proprietary eddy current based systems. During this time MP has serviced more than 300 customers in more than 60 countries. Currently, MP carries out more than 120 inspections annually.
Introducing LEO-SCAN - the MP eddy current system for the inspection of reformer tubes from the outside. LEO stands for Laser Eddy current Outside scanning. It is important to note that all probes, mechanical parts and test instruments are either built by MP, or built to the specifi cations of MP by others. This sole source, in-house approach is why the LEO-SCAN system is the most proven and accurate system in use today. The eddy current crack detection system of LEOSCAN penetrates the complete tube wall in the search for cracks that could lead to failure. The LEO-SCAN system also utilizes dual axis laser diameter measurements to measure diametrical strain. The starting point for collecting the data is only 20 mm from the fl oor. The LEO-SCAN can easily inspect 250 tubes per shift with or without catalyst in the tubes.
There are several different reformer designs, such as top-fired, floor-fired, terrace wall, side-fired and circular designs. In each case there is an area where damage normally is found. Based on the tremendous experience of the inspectors, these problem areas are given extra scrutiny.
LEO-SCAN will detect damage that occurs due to normal operating conditions as well as other events, such as fl ame impingement, catalyst issues, loss of fl ow, spring support issues and fl ue gas distribution issues. These abnormal conditions can distort the relationship between creep-strain and cracking.
MP encourages clients to perform a baseline inspection on new tubes. This baseline inspection can find abnormalities in the tubes, such as machine gouges, hot tears and other issues. It also provides a “fingerprint” of each tube for later comparisons.
Each pigtail is inspected using the Foerster Magnetoscop. Results show the progress of carburization due to the intersitial diffusion of the carbon atoms through the microstructure of the pigtail.
All damage is presented to the client in tabular and graphic 3D formats. These views can show the operators where the trouble or high heat areas are in the reformer and allow for diagnosis and correction of these problems. All data can be overlaid and compared due to the amazing repeatability.
The data, coupled with plant operational data, can be used for a remaining life study should the client desire it. MP works with several very experienced third party metallurgical specialty companies to assist in any high-level assessment work on an independent basis.