Refinery & Petrochemical
Comprehensive NDT services and solutions to the refining and petrochemical industries
NDT services for refinery and petrochemical
There can be fewer more risky industries and environments than those involving petrochemicals and power generation. Harsh, challenging and in constant danger of cataclysmic incidents, the focus on health and safety is understandably high. Harmonious working between man and materials is essential and, whilst much human endeavour can be observed and regulated, inert equipment is always prone to the unexpected. Minimising risk is very much a way of life. Both industries rely heavily on arterial infrastructure; tubes of all dimensions and uses, being especially dependent on heat exchangers and boilers. Often tubes are bundled together making even visual inspection difficult or hazardous; in many cases normal ultrasonic and radiographic inspections fail to achieve results to an acceptable standard. Allied to these safety issues are economic factors relating to downtime costs and production shutdowns, frequently measured in weeks. Risky reliance on visual inspection and destructive testing of many small-bore tubes has led to past uncertainty and potentially expensive decisions as to whether and when to repair or replace.
INSPECTION, NDT & SITE SERVICES
This process is well adapted to the inspection of small-bore ferromagnetic tubes such as carbon steel. Using electromagnetic techniques this is now the industry standard inspection for boilers and heat exchangers due to its low frequency (typically 50-1000Hz). The probe consists of two coils in a sen-receive configuration which are inserted into the tube. The energised exciter coil transmits a signal to the detector coil located some distance away. This signal passes through to the outside tube wall returning to arrive at the detector coil. With wall thinning there is less shielding hence the return time (greater phase) and attenuation (greater amplitude) is shorter. Phase and amplitude traces are generated as the probe is pulled through the tube as recorded data identifies the metal loss. Flaw sizing is also possible with RFT enabling depth, length and circumference to be accurately calibrated.