Conditional operation of boiler components working under creep conditions until replacement

Abstract

One of the more serious operational problems is thermo-fatigue damage detected on internal surfaces of pressure elements (chambers of steam coolers and superheaters), especially those working under creep conditions. Such damages are practically irreparable, especially during a previously planned overhaul. They require prefabrication of new elements. Using the technology of digital twins, fracture mechanics and remote diagnostics Pro Novum has developed and implemented the methodology of conditional operation (until the element is replaced or the boiler is shut down), which allows supervision of the damage under the control of an appropriate system (software). The system can simultaneously control the possible development of a dozen or so damages and assess the condition of the element in an on-line mode. The elements working the longest in the conditions as above have worked for 2 years now. Control NDT (UT) during operation and destructive tests after the disassembly of the elements confirmed possibility of computational monitoring of crack propagation with the accuracy sufficient for practical purposes.