Can the superheater tubes of biomass boilers be treated with an outer enamel coating to address alkali metal corrosion?
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Due to the special properties of their fuel, biomass boilers contain high levels of alkali metals and chlorine, which causes severe corrosion of the superheater tubes in these boilers. In modern high-temperature, high-pressure boilers, TP347 material is commonly used, but its service life still does not exceed two years; many biomass power plants continue to be plagued by this problem. I thought: if an enamel layer is baked on the outer surface of the tube, it would effectively prevent alkali metals from corroding the metal surface of the tube, provided that the manufacturing process for coating the tube with enamel can be resolved. I wonder if any colleagues have conducted experiments on this? Is there any experience that can be referenced? Everyone is welcome to discuss.
It shouldn’t be enamel; the enamel coating process can’t withstand very high temperatures. You could say that using a ceramic layer is acceptable, but on a metal surface it cannot expand synchronously with the metal, which will cause cracking.