Failure analysis of an EDC incinerator quench nozzle

The quench nozzles (Hastelloy C-276) installed in the firebox of an incinerator in the EDC unit of a Saudi petrochemical plant experienced frequent premature failures. One damaged quench nozzle (male and female parts), therefore, was investigated by chemical analysis, optical microscopy, and EDS techniques in order to find out the cause and preventive solutions. The study indicates that the quench nozzle was corroded likely due to hydrochloric acid (HCl) formed in the hot service following the failure of the refractory lining. The presence of both moisture and chloride (from EDC) made HCl formation possible. Upgrading the construction material to Alloy C-59 is recommended. Alternatively, ceramic coatings of SiC can be applied.