Publications

Thermal expansion in liquid-filled closed systems poses significant overpressure risks, particularly in environments with large temperature fluctuations, such as Indonesia’s oil and gas facilities. Current industry standards often rely on single-layer mitigation (e.g., pressure safety valves), but repeated activations due to daily thermal cycles compromise reliability and safety. This paper shares lesson learned by examining three real-world case studies to evaluate gaps in existing practices, propose context-specific solutions, and derive actionable recommendations to enhance thermal expansion management in design and operations.

The methodology focused on three case studies: (1) a condensate loading line experiencing repeated PSV openings and leaks due to day-night temperature variations; (2) a surface safety valve (SSV) hydraulic line with a stuck pressure relief valve (PRV) and burst disc rupture caused by thermal fatigue; and (3) an LNG loading line at risk of catastrophic overpressure due to a misconfigured fail-closed valve. Each case was analyzed using process simulation software to quantify pressure buildup under thermal expansion, structured root cause investigations aligned with internal protocols, and validation of solutions against industry standards (e.g., API 521) and hydraulic expansion models. Historical data, including a 2022 LNG facility incident, informed the evaluation of risks such as blocked relief paths and trapped liquids.

The results demonstrated that tailored interventions—adjusting pressure detection systems, removing check valves to incorporate accumulators, and redesigning actuators to fail-open—effectively mitigated thermal expansion risks in all three cases respectively. These solutions aligned with the objectives of the study to improve safety system and reliability and eliminating recurring incidents. However, the findings revealed systemic gaps, such as inadequate relief system design and insufficient monitoring of thermal valve performance. Frequent PSV activations accelerated wear, underscoring the need for multi-layered safeguards and proactive operational practices. The study recommends implementing an additional mitigation layer if daily thermal expansion release is anticipated.