Efficient Online Leak Sealing of High-Pressure Ammonia Vapour & Carbamate Leak at a 1.8 m Flange
In large-scale fertiliser plants, even a small flange leak can cascade into major safety, environmental, and financial consequences. When faced with an ammonia vapour and carbamate liquid leak at 75 bar and 170 °C, Nicco Engineering’s sealing specialists demonstrated how precise inspection, rigorous safety protocols, and the right sealing compound can arrest a critical leak—without a plant shutdown.
The Challenge
At a urea synthesis facility, a flange joint with an outer diameter of 1.8 m and a 32 mm gap began leaking under full operating conditions. Ammonia vapour posed a severe inhalation risk and environmental concern, while the carbamate liquid drained in volume per day—a significant loss to the client. Shutting down for repairs would have cost hundreds of thousands in lost production and restart logistics. An online sealing solution was essential.
Inspection & Detailed Assessment
Manual Inspection:
- Visual confirmation of vapour plume and liquid droplets.
- Measurement of flange gap uniformity.
Drawing Verification:
- Cross-referenced plant piping and instrumentation diagram (P&ID) and mechanical drawings to verify flange dimensions and spacer alignment.
- Identified asymmetry in spacer thickness and bolt-hole alignment as likely contributors to uneven sealing surfaces.
Safety Protocols & Site Preparation
- Permit to Work (PTW): Secured hot-work and confined-space clearances.
- Personal Protective Equipment: Full-face respirators with SCBA, ammonia-rated gas monitors, and acid-resistant suits and gloves.
- Emergency Readiness: Standby spill-control and neutralizing agents on hand.
Sealing Solution & Execution
We selected Compound 2B, a BIS-approved material (per BIS IS 18159:2023) capable of withstanding temperatures to 300 °C. NES 2B was injected using an injection gun, gradually the sealant filled the flange gap thereby arresting the leak.
Results & Validation
- Pressure Test: Gradual re-pressurization to 75 bar—no detectable leak or pressure drop.
- 24-Hour Monitoring: Stable pressure readings without deviation.
Impact & Client Feedback
By executing a rapid, well-orchestrated online seal, Nicco Engineering:
- Prevented significant production loss during the shutdown.
- Mitigated health and environmental hazards without interrupting plant operations.
- Demonstrated compliance with national sealing standards.
“Nicco’s team delivered exceptional expertise and safety diligence—halting a critical leak in hours and saving us significant downtime. Their professionalism and the performance of Compound 2B were outstanding.”
Conclusion
This case underscores the value of detailed inspection, adherence to safety and standards, and the selection of a high-performance sealing compound in addressing severe, high-pressure leaks online—safeguarding both people and productivity.
