Real-time product release of LNG

Application Note | Oil & Gas

  • Quality release certificate and bill of lading available directly after LNG loading
  • Avoiding disputes due to AMADAS automated instrument validation
  • ISO 8943, GPA 2172, ASTM 4784 and GIIGNL calculation certified by NMi

Antecedentes

A natural gas hub in Australia has a capacity to produce 8.9 metric tons of LNG per year. The hub operator was looking for methods to obtain real live information on the quality and the quantity of the gas produced and shipped. In their current setup the operator was using off-line lab analysis combined with dynamic flow measurement. The L-QRS solution offered the customer instant availability of bill of lading and quality certificates.

Requisitos de la medida

Transferring LNG is based on a highly accurate measurement of LNG quantity and quality. In the past, the quantity measurement was mainly based on tank level measurement. In recent years this has been slowly shifting towards dynamic measurement using flowmeters. The quality measurement is usually based on a lab analysis of a representative sample of the LNG that was loaded.

Traditionally, a representative sample is obtained by an automated sampling system that regularly extracts a small amount of LNG during the loading process. After loading has been completed, a sample canister is then available that holds a representative sample of the cargo in the ship. The sample canister is subsequently taken out and transported to the LNG laboratory for analysis. A second similar sample canister is stored on the ship for later analysis in case of a dispute.

While this method has been in use for many years, it has some drawbacks: Analysis can only start after the load has been completed. The quality release certificate is usually only available after the ship left berth. Lab operation and manual calculation of calorific value leave room for disputes. Manual handling of cryogenic sample cans is required.

To improve this process the operating company and KROHNE initiated a solution to measure LNG quality directly during loading.

This includes:

  • Automatic calculation of calorific value per typical LNG standards
  • 3rd party verification that calculation methods were correctly implemented
  • Guarantee performance and traceability of instrumentation used to measure LNG quality
  • Generation of quality release certificate and bill of lading immediately after loading has been completed

La solución de KROHNE

Based on its SynEnergy metering software, in close cooperation with the gas hub operator, KROHNE developed the L-QRS LNG quality release software package. The L-QRS software includes ISO 8943, GPA 2172, ASTM 4784, ASTM E178 and GIIGNL calculation methods, with correct implementation of these methods certified by NMi. To verify the performance of the instrumentation used for measurement of the LNG, the integrated CalSys module offers analyser management and data acquisition (AMADAS) functionality, amongst others per ASTM D3764, ASTM D6299 and OP 97-30425.

The L-QRS software is configured to work with the existing infrastructure, instrumentation and analyzers such as gas chromatographs. The core software runs on a SUMMIT 8800 Custody Transfer flow computer, with the operator interface integrated in the central HMI.

Beneficios para el cliente

The L-QRS software avoids discussion over the amount of energy transferred as the system is indispuable compliant to GSPA. Additional benefits of L-QRS include:

  • Product give-away is minimized due to lower system uncertainties and outlier detection
  • Instant availability of the bill of lading and quality certificates, avoids costly retrospective corrections once the vessel has departed
  • Eliminates human errors in the data processing as the information flows are fully automated
  • Reduces maintenance costs by an average of >25% using the AMADAS benefits of Calsys®
  • Increased availability of critical instruments (>95%) ensuring constant and reliable quality measurements.
  • Structured and consistent validation of analyzers and instruments providing solid traceability and auditability.
  • Data is securely stored and together with the certified calculation fully auditable

Productos utilizados

Computador de caudal para la medida de transferencia de custodia (CT)

  • Solución económica gracias al diseño modular de hardware y software
  • Pantalla táctil gráfica en color para la máxima transparencia del proceso
  • Facilidad de acceso del operador para un mantenimiento eficaz en términos de tiempo
  • La monitorización automática del rendimiento alarga los intervalos de recalibración

Soluciones relacionados

Solución software para operaciones eficientes de carga de GNL

  • Disponibilidad inmediata del certificado de calidad y del conocimiento de embarque gracias a la medida de la calidad en tiempo real 
  • Certificado por el NMi y conforme con ISO 8943, GPA 2172, ASTM 4784, GIIGNL
  • Cálculos de la energía, balance de masa de carga e informes de facturación sobre caudal de retorno de vapor.

Solución para el monitoreo y reporte continuo de procesos

  • Software HMI/SCADA para soluciones de medida
  • Tecnología de web segura HTML5 de última generación
  • Optimización de los resultados de funcionamiento gracias al mantenimiento predictivo
  • Integración fácil en redes DCS y ERP existentes

Solución para la gestión de analizadores y la adquisición de datos (AMADAS)

  • Monitorización del rendimiento real de equipos de medida de la calidad (QMI)
  • Validación automatizada de analizadores, control estadístico de procesos y mayor disponibilidad de analizadores de procesos críticos
  • Cumple las normas y métodos internacionales (ASTM D3764, ASTM D6299, OP 97-30425, etc.)
  • Acceso versátil mediante conexión remota al sistema
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