Abstract: Waste heat boiler for Claus furnace is the core equipment of sulfur recovery unit and its stable operation is crucial for the sulfur recovery unit. This paper describes the inspection of heat exchanger tube and corrosion products by scanning electron microscope (SEM), energy spectrum analysis (EDS) and X-ray diffraction (XRD) after corrosion perforation occurred in the heat exchanger tube of waste heat boiler for Klaus furnace in a company's 140 kt/a sulfur recovery unit. It analyzes the corrosion causes based on the results of the inspection. The results show that the oxygen corrosion of the heat exchanger tubes due to excessive dissolved oxygen content in deoxygenated water is the main cause of corrosion perforation of heat exchanger tubes. By raising the operating temperature of the deaerator and installing additional chemical deoxidizing facilities, the dissolved oxygen content in the deoxidized water has been effectively reduced, and the recurrence of the above situation can be avoided.

Key words: sulfur recovery unit, waste heat boiler, dissolved oxygen corrosion, cause analysis