IN-PLANT CORROSION TEST-RESULTS OF CANDIDATE MATERIALS IN COAL-GASIFICATION PLANTS

In-plant corrosion tests were carried out in two coal gasification pla nts. This research was sponsored by the Agency of Industrial Science a nd Technology and the New Energy and industrial Technology Development Organization (NEDO). At the HYBRID pilot plant (fluidized-bed gasifie r), the test programme was conducted to evaluate the low temperature c orrosion behaviour of construction alloys. The corrosion rate is stron gly dependent on the temperature and peaks at about 300 degrees C. At the HYCOL pilot plant (entrained-bed gasifier), the main purpose of th e test programme was to obtain corrosion data on candidate heat exchan ger tubing alloys. The test alloys were carbon steel, Cr-M o steels, a ustenitic stainless steels, Ni-base alloys and diffusion coatings. Acc ording to the first examination results from the heat recovery boiler, the corrosion resistance of the test alloys increases with Cr content in the alloy. Cr-Mo steels an severely attacked through sulfidation a nd austenitic stainless steels are slightly attacked through oxidation and internal sulfidation.