Corrosion of a chimney liner operated for 130,000 hours

The tests were carried out for a coal-fired boiler heating a single-family house with a usable area of 220 m2. The tests covered the chimney liner (structure and surface layer - produced oxides/deposits), hard coal (eco-pea coal) and furnace ash. The chimney liner was located in a chimney made of bricks joined with concrete. A chimney liner made of austenitic steel was tested. The chimney liner was operated for 130,000 hours. The chimney insert was studied on the inner and outer side the respective cross-section. Coal with a grain size of 50-210 mm was analyzed. The bottom ash consisted of both loose ash and a mass of glassy sintered ash, the so-called slag. Thorough examinations of the researches materials comprised: microscopic examinations using an digital microscope VHX-7000 and scanning electron microscopes Jeol JSM-6610LV. Analysis of the chemical composition using Energy dispersive X-ray spectroscopy (EDS) in conjunction with the scanning electron microscopy (SEM). The surface topography (roughness) was measured using a VHX microscope using a Gaussian filter. The following parameters were determined on the basis of the tests: arithmetic mean height, maximum height, height of the highest peak, depth of the lowest depression, root mean square height, skewness, kurtosis.