Sour water systems are an integral part of all refineries. They are designed to collect sour water from numerous places in a refinery for hydrogen sulfide removal. Because of the complexity of these systems, the pressure relief analysis is inherently difficult.
This paper discusses critical considerations in the pressure relief analysis including design flaws that set traps for operators, deficiencies in operating procedures, effects of light hydrocarbons entering a sour water system and surprising conclusions from the pressure relief analysis. Also presented will be potential mitigations for existing systems and design considerations for new systems.