A LNG tank gauging system with high measuring performance is critical for ensuring accurate inventory management, safety, and operational efficiency in LNG storage and transport facilities. Combining advanced technologies, such systems provide reliable measurements of critical parameters like liquid level, density, temperature, and pressure in LNG tanks.
Key Components of a High-Performance LNG Tank Gauging System
Level Measurement:
- Servo Tank Gauges: Highly precise, capable of measuring the liquid level, interface level, and density by utilizing a servo-driven displacer.
- Radar Gauges (Guided Wave Radar or FMCW): Non-contact measurement, unaffected by temperature, pressure, or vapor conditions in LNG tanks.
Temperature Measurement:
- Multiple-Point Temperature Probes: Measure temperature at various levels in the tank to account for stratification and provide accurate average temperatures.
Density Measurement:
- Float-Based Density Measurement: Measures the density of LNG at specific levels for accurate mass calculations.
- Thermal Density Probes: Combine temperature and density measurements for enhanced accuracy.
Pressure Sensors:
- Measure vapor pressure and assist in calculating mass and volume using tank pressure and liquid density.
Tank Management Software:
- Integrates measurements of level, temperature, and pressure.
- Calculates critical values like gross and net volume, density, and mass.
- Provides real-time monitoring and inventory management.
Safety Systems:
- Integrated alarms for high/low level and temperature.
- Overfill protection devices to ensure operational safety.
Features of High-Performance LNG Tank Gauging Systems
High Accuracy:
- Systems achieve accuracies within ±1 mm for level measurement and ±0.1°C for temperature measurement, ensuring precise inventory control.
Cryogenic Compatibility:
- Designed to function reliably in extreme low-temperature environments (below -160°C) common in LNG applications.
Real-Time Data Transmission:
- Provides continuous and instantaneous updates on tank conditions, crucial for safe operation and decision-making.
Redundancy and Reliability:
- Use of redundant sensors ensures reliability in case of equipment failure.
- Advanced diagnostics to predict and prevent system malfunctions.
Remote Monitoring:
- Supports integration with remote monitoring systems, allowing operators to oversee multiple tanks or facilities from a central location.
Compliance with Industry Standards:
- Adheres to standards like API 625, ISO 20519, and OIML R85 for LNG measurement and storage.
Advantages
Optimized Inventory Management:
- Accurate data on LNG levels and mass ensures proper inventory control, reducing losses and discrepancies.
Improved Safety:
- Precise measurement reduces the risk of overfilling, spillage, or dangerous pressure buildups.
Cost Efficiency:
- Accurate gauging minimizes waste and maximizes the value of stored LNG.
- Reduced downtime through predictive maintenance and real-time monitoring.
Flexibility:
- Suitable for fixed storage tanks, floating LNG (FLNG) facilities, and LNG carriers.
Leading LNG Tank Gauging Systems
Emerson Rosemount Tank Gauging System:
- Features high-accuracy radar level gauges and multiple-spot temperature sensors.
- Provides integrated solutions with inventory management software.
Honeywell Enraf LNG Tank Gauging:
- Offers servo and radar level gauges with advanced diagnostic capabilities.
- Integrated safety features for overfill prevention.
Kongsberg Marine Automation:
- Combines level, pressure, and temperature sensors with high-performance software.
- Designed for marine and shore-based LNG operations.
Endress+Hauser Proservo NMS80:
- High-precision servo gauges designed specifically for cryogenic LNG storage tanks.
- Combines density profiling with advanced data analytics.
Integration with Automation Systems
Modern LNG tank gauging systems often integrate with distributed control systems (DCS) and SCADA platforms, allowing for centralized monitoring, data analysis, and process control.