ON-LINE BOILER CORROSION MONITORING IN RDF-COAL GO-FIRING AND WTE PLANTS

摘要

RSE developed a new corrosion monitoring system suitable to be installed in harsh environments, whose most innovative feature is the possibility to measure on-line the consumption due to the corrosion of materials exposed into the boiler; different types of probes have been designed for the exposure both into the convective pass of the boiler (T&R-type and multi-material MM-type) and in the membrane wall of the combustion chamber (T-type). The tubular sample of T&R probe simulates a real section of a tube of the bundles of the boiler, where the corrosion attack is normally more relevant, allowing to reproduce the fluid dynamics effects existing on the real bundle tubes due to the flue gas stream which cause a not homogeneous consumption of the material. The temperature of the sample can be set at the value of the tube of the plant for measuring its real long-term consumption rate or alternatively can be increased to simulate some different plant operation assets with higher electrical efficiency; high accuracy measurement of the residual thickness of the exposed sample is performed by T&R-type probe, which was confirmed by many post-exposure metallographic examinations. Another kind of probe (T-type) is designed for the installation in the membrane wall of the boiler and in this case the material consumption due to the corrosion is measured off-line by a metallographic section of the exposed sample comparing the corroded surface to a reference Pt pin.