Session: Corrosion in the Biofuel and Biomass Industry
Effect of Temperature and Humidity on Corrosion in NH₄Cl environments (C2026-00076)
Monday, March 16, 2026
8:30 AM - 9:00 AM Central
Location: 371 AB
Earn .5 PDH
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Ammonium chloride (NH₄Cl) is recognized for its corrosiveness in refinery sector affecting metallic alloys by different under-deposit corrosion mechanisms. Corrosion is focussed where a local environment develops under the hygroscopic NH4Cl salt. In biofuel refining and co-processing units, NH₄Cl-rich environments may form either through combination of HCl and NH₃ present as vapors or via sublimation of the salt followed by its deposition on cooler parts. In the latter scenario, ambient humidity and temperature play critical role: deposited NH₄Cl readily absorbs moisture, leading to deliquescence and the formation of a highly corrosive aqueous phase. Given the dual influence of temperature and humidity on corrosion behavior, it is essential to assess the compatibility of corrosion-resistant alloys (CRAs) under these conditions. This study investigates the corrosion performance of various CRAs in NH₄Cl environment under controlled temperature and humidity conditions. Experimental evaluations were conducted across a temperature range from 130°C to 220°C, with susceptibility to stress corrosion cracking (SCC) assessed as key performance indicators. The findings highlight the synergistic effect of elevated temperature and humidity in accelerating corrosion processes, underscoring the need for robust material selection strategies in moisture-sensitive environments.
