Case Study: LDAR Inspection Identifies and Resolves Quantifiable Methane Leak on Gas Booster Compensator Valve
Overview
During a routine Leak Detection and Repair (LDAR) inspection at a biomethane-to-grid anaerobic digestion facility, a significant methane leak was identified on a gas booster unit. The leak, measured at 3 kg/h, was traced to a defective compensator valve. Timely intervention prevented substantial commercial loss and ensured continued compliance with environmental permitting requirements.
Background
The site exports biomethane to the national gas grid, with methane produced through anaerobic digestion, upgraded, and injected under a regulated and metered agreement. Given the high energy value of grid-quality methane, any leakage directly affects revenue and compliance with sustainability targets.
As part of the site’s quarterly LDAR programme—conducted using optical gas imaging (OGI) and flame ionisation detection (FID)—anomalies were investigated around the gas booster skid, a critical part of the upgrading system.
Leak Identification
Location: Compensator valve on gas booster skid
Detection Method: FLIR GF320 OGI camera and calibrated FID
Leak Rate: 3 kg/h of methane
This equated to:
~30 m³/h of methane
~300 kWh/h of lost energy (based on 10 kWh/m³)
£24/hour loss, based on an average biomethane export value of £0.08/kWh
Potential annualised loss: £210,000/year if undetected
Root Cause Analysis
Engineering investigation revealed that the compensator valve's internal seal had failed due to prolonged vibration and thermal cycling on the gas booster. Material fatigue of the valve seat and insufficient damping on the skid contributed to the deterioration.
Corrective Actions
The defective valve was isolated and replaced within 12 hours.
Anti-vibration mounts were installed on the gas booster skid to prevent future mechanical stress.
A planned preventative maintenance (PPM) update was implemented, including inspection of gas-side seals and compensators every 6 months.
Operators received refresher training in OGI camera usage to improve early leak recognition.
Results and Benefits
Immediate prevention of 3 kg/h methane loss
Recovered value of ~£24/hour, equating to ~£210,000/year
Strengthened reliability of gas upgrading infrastructure
Reduced fugitive emissions, aligning with EA permit conditions and ISO 14001 commitments
Enhanced confidence in LDAR programme during external compliance audit
Conclusion
This case underscores the measurable impact of LDAR on commercial performance and environmental compliance in biomethane-to-grid operations. Rapid leak detection and repair not only protected revenue but reinforced the value of proactive asset integrity management.
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