What is the purpose of a 'custody transfer meter' in LNG loading operations?

The purpose of a 'custody transfer meter' in LNG loading operations is to accurately measure the quantity of LNG transferred between the seller and the buyer for commercial and accounting purposes. 'Custody transfer' refers to the point at which the responsibility for the LNG shifts from one party to another. The custody transfer meter must meet stringent accuracy standards to ensure fair and transparent transactions. These meters are typically calibrated and certified by independent third-party organizations to ensure compliance with international measurement standards, such as those established by the International Organization of Legal Metrology (OIML) or the American Petroleum Institute (API). The meter measures the volume or mass of LNG passing through the loading line. However, volume measurements need to be corrected for temperature and pressure to determine the actual mass or energy content of the LNG. Therefore, custody transfer metering systems include not only flow meters but also temperature and pressure sensors, as well as sophisticated flow computers that perform real-time corrections. Common types of flow meters used for custody transfer include Coriolis meters and ultrasonic meters, which offer high accuracy and reliability. The accuracy of the custody transfer meter is critical because even small measurement errors can translate to significant financial losses, given the large volumes and high value of LNG being traded. The meter readings are used to determine the amount the buyer pays the seller for the LNG.