Investigation of austenitic stainless steel corrosion resistance against ash deposits from co-combustion coal and biomass waste

A high chromium concentration in the boiler material is believed to increase corrosion resistance, especially at high temperatures. It is related to the formation of a protective layer on the surface of the metal, called a chromium oxide (Cr₂O₃) layer. However, the impact of alkali and chlorine from co-combustion coal with biomass in power plants can harm this protective layer, reducing its effectiveness and potentially leading to increased corrosion. Therefore, it is important to evaluate the impact of these factors on the corrosion resistance of high-chromium materials. This research investigates coal co-combustion with empty fruit bunch (EFB) and plastic waste on the corrosion resistance of austenitic stainless-steel material on a laboratory scale using drop tube furnaces. The investigation steps included probe observation, SEM-EDS on ash and probe material, and XRD. The analysis indicates that the ash from the coal sample did not affect the probe, unlike the coal with EFB or EPL (mixture of EFB and plastic crackles), which caused up to 14% oxide layer degradation. The existence of alkali chloride, sulfate, and silicate in the ash that is still adhered to the surface of the probe can reduce the corrosion resistance of the metal.