Introduction
Liquefied Natural Gas (LNG) facility involve complex operations that manage cryogenic temperatures, high-pressure systems, and flammable materials. These characteristics pose significant safety challenges across various process stages such as storage, dispensing, vaporization, and filling. Conducting a Hazard and Operability (HAZOP) study at the design or modification stage is essential for identifying process deviations and ensuring safe, efficient operation of LNG infrastructure.
Methodology
The HAZOP study follows a structured approach, ensuring a comprehensive review of potential hazards and operability issues. Key steps include:
- Node Identification: Breaking down process systems into manageable sections (nodes) for focused analysis.
- Guideword Analysis: Applying standard guidewords like No Flow, More Pressure, Less Temperature, etc., to detect potential deviations.
- Cause & Consequence Evaluation: Assessing possible failure scenarios and their effects on safety, operations, and the environment.
- Safeguard Review: Evaluating existing control systems both instrumented and procedural that mitigate risks.
- Recommendations: Proposing additional safeguards or modifications where existing controls are inadequate.
- Documentation Tools: HAZOP studies are often supported by PHA software to ensure structured and traceable analysis.
Outcomes
The outcome of a HAZOP study for LNG facility includes a set of actionable recommendations to address identified risks.
1. Thriveni – LNG Facilities, Keonjhar, Odisha
Project Overview
Thriveni Earthmovers Private Limited established a LNG Filling Station in Keonjhar District, Odisha. These were developed to support clean energy distribution via cryogenic LNG handling systems, catering to portable cylinder filling and direct dispensing for downstream users. The facility was designed with integrated Boil-Off Gas (BOG) utilization and pump-assisted operations for enhanced energy efficiency.
Project Insights
iFluids Engineering conducted detailed HAZOP studies covering:
- LNG Unloading Systems from road tankers into twin 20 KL cryogenic storage tanks
- Pump Skid Operations for filling 448L and 980L cylinders and for LNG dispensing
- BOG-Powered Gas Generators for on-site power needs
- Safety and Instrumentation Systems including:
- Emergency Shutdown Systems (ESD/ESDV)
- Pressure, Level, and Flow transmitters (PT, LI, MFM)
- Alarms (LAH, PAH), interlocks, and strainer systems
- Support Utilities such as nitrogen purging, firefighting water systems, insulation, and strainer flushing loops
Conclusion
The HAZOP studies led to key safety and operability recommendations, as mentioned below
- Provision of standby pumps for operational redundancy
- Enhancement of leak detection systems and ESD logic validation
- Routine maintenance of strainers and improvement in SOP compliance
- Updating P&IDs and control panel alarm logics for better clarity and reliability