Abstract: Hydrogenation units are core facilities for crude oil processing at refineries. With the increasing inferior quality of feedstocks (high sulfur, nitrogen, and chlorine content) and increasingly severe operating conditions, corrosion risks and failure hazards have been significantly intensified. Among these challenges, the corrosion-induced failures in high-pressure air coolers have become a critical industry-wide challenge. This paper analyzes the impact of increased nitrogen content in the feedstock of a refinery's wax oil hydrotreating unit on the air cooler of the hot high-pressure separator. Through systematic corrosion assessment and calculation, it conducts comprehensive corrosion control design encompassing material selection, process corrosion prevention and corrosion monitoring/inspection. The paper proposes effective anti-corrosion strategies. This integrated approach provides robust support for ensuring the long-term safe and stable operation of high-pressure air coolers in hydrogenation units.

Key words: hydrogenation unit, high-pressure air cooler, material selection, process anti-corrosion, corrosion monitoring/detection, integrated design