February 2018, a leak was visible in the spherical dome part of a HP Scrubber in a urea plant. The plant was stopped immediately to attend the leak. Upon opening of the HP Scrubber sphere, it became clear that severe corrosion occurred on the liners. The liner was covered with huge amount of corrosion products and many cracks were visible. Unfortunately, these cracks resulted in leaks which were not noticed. Therefore, corrosion of the carbon-steel pressure part commenced undetected. The paper describes the root cause of the corrosion damages as well as the successful repair. This case demonstrates the importance of a reliable and robust leak detection system to operate critical high-pressure equipment safely.

This paper was presented at the AICHE Ammonia Safety Conference 2019 in San Francisco.