Acoustic emission monitoring of abrasion and corrosion in double-walled pipelines

At KRONOS TITAN, double-walled pipelines are used in production of Titandioxid. An abrasive medium is transported in the inner pipe at high temperatures. In the outer pipe, cooling water ensures that the process is cooled down. During the process, it is important that no abrasion leads to complete wall erosion and thus to leakage between the inner and outer pipe. During a test campaign lasting several months, a section of such a pipe was instrumented with acoustic emission measurement system on the outer pipe and the abrasion process in the inner pipe was monitored with AE until the removal of the pipe section. Different AE-signal parameters (Events, Hits, Energy and Frequency) were investigated regarding their suitability and are discussed in this contribution. The results of the acoustic emission measurements with regard to the location and progress of damages were then compared and verified with classic NDT test results.