Failure analysis of abnormal leakage in hydrogen cyanide reactor

Hydrogen cyanide (HCN) is a crucial building block for various industrial chemicals in organic synthesis. Due to its high toxicity to humans and the environment, meticulous care is required in the synthesis, use, and disposal of HCN and its derivatives. This study investigated the premature failure of the HCN reactor, a core component of the HCN production system. Despite a design life of 20 years, the reactor experienced abnormal leakage after only 4 years of operation. Comprehensive investigations revealed that corrosion pits caused by localized corrosion formed at the circumferential welding seam of the reactor shell. This problem was further aggravated by vortex scouring from the pressurized water medium. Additionally, residual stress at the welding seam contributed to decreased toughness. The analysis highlighted the intricate relationship between localized corrosion and vortex scouring as the primary mechanisms leading to perforation and leakage of the reactor shell. Based on these findings, effective countermeasures were proposed to prevent similar future failures, potentially enhancing the operational safety and reliability of the HCN production system.