A sonic approach for the measurement of gas temperature in power generation boilers

The paper describes the recent improvements of a proprietary system for the estimate of temperature distributions inside gas flows by sonic methods, with special attention to applications in the steam boilers of power stations. In particular, together with a short review of the original configuration, the problem of installation and maintenance of the waveguides is first discussed and the newly devised solutions are shown. Then the revision of the signal processing algorithms, employedfor the determination of the temperature along the acoustic paths between any two transducers, is described; the aim was to reduce the scattering of the measurements and to improve their reliability, despite of the strong levels of background noise and of the highly non-stationary system under measure. Finally some results obtained by preliminary tests carried out on a coal fired 660 MW steam boiler are documented in some detail.