Furnace material
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There is an ammonia combustion furnace on site; electric heating is used to cause ammonia to react with oxygen in the air to produce water and nitrogen. The normal operating temperature is around 900°C; if there is a sudden large release of ammonia, the temperature inside the furnace can reach 1000°C or even higher. Since the original equipment was imported, we aim to localize the spare parts; therefore, we would like to consult first on what material would be suitable for such incinerators. PS, the ammonia inlet pipeline at the furnace end is made of stainless steel 316L, but it is not resistant to ammonia corrosion, so it needs to be rewelded every two years. So stainless steel 316L won’t do.
I’m not sure which fellow sailor is familiar with materials in this area; I hope you can share your knowledge
I checked API-571; the issues related to ammonia are as follows: 1. Ammonia-induced stress corrosion cracking: This is not a problem with stainless steel SS316 (as indicated in the tables, the corrosion rate is very low). 2. Amine corrosion: Stainless steels of the 300 series have high corrosion resistance. So you might want to verify whether corrosion is indeed caused by ammonia (especially in the inlet pipelines, which are usually at room temperature and unlikely to be heated). I suspect that other substances present in ammonia might be the actual cause
It is confirmed that there is only ammonia, with nothing else in the system.
Silicon carbide: are there any manufacturers or information available in this area?
Silicon carbide exhibits outstanding performance in terms of heat and corrosion resistance; you can contact relevant manufacturers for inquiries.
Okay, thank you for that information
I did some online research; basically, ammonia is corrosive, but if the substance contains oxygen and water, certain negative reactions can occur that lead to corrosion. Therefore, it’s necessary to first determine the cause of the corrosion before choosing a more suitable material