Ship loading in the oil & gas industry

In the oil industry, the major product transported by sea has previously been crude oil. However, more and more refined products are also being transported by sea. Oil tankers deliver around 2.5 billion cubic meters of crude oil and refined products each year, and provide the next most efficient transport system after oil pipelines. Tanker sizes range from inland or coastal tankers that hold a few thousand cubic meters, up to ‘Ultra Large Crude Carriers’ (ULCC) that can hold up to 650,000 cubic meters. Tankers have different compartments and are often equipped with a marine tank monitoring and alarming system, such as the KROHNE CARGOMASTER, which uses radar-based level measurement sensors. Most tankers also have inert gas blanketing systems, using mainly nitrogen, that avoid the possibility of any explosive gas mixtures being present in the ullage space above the product.

Loading and unloading of tankers is done via a direct hook-up to pipelines, or through a series of loading arms. A custody transfer flow measurement system is required, to determine the exact quantity of oil delivered to or taken from the tanker: this also often includes an analyzer to confirm the quality of the product. The system can include degasser units to eliminate any unwanted gas entrained during the transfer.

For many years KROHNE has designed and supplied these custody transfer metering systems used for ship loading and unloading, based on specially developed ultrasonic and Coriolis flowmeters. In addition KROHNE has vast experience in the supply of on-site meter proving systems, such as ball or mobile provers, to validate the flowmeter performance. Usually the product transfer is made into a storage tank, where KROHNE supplies radar based tank gauging equipment and level alarm switches.