Description

Level measurement in degassers

Requirements

  • Continuous measurement to adjust level in the degasser

Description

Pump lubrication monitoring

Requirements

  • Avoid damage to bearings of the pump
  • Indication of the flow

Description

Custody transfer measurement of crude oil or refined product

Requirements

  • High accuracy measurement of valuable products
  • Need for diagnostics to ensure measurement accuracy

Description

Tank level measurement

Requirements

  • Control of the tank farm
  • Inventory measurement

Description

Continuous nitrogen blanketing

Requirements

  • Maintenance of the non-explosive atmosphere
  • Low flows with mostly low pressures
  • Monitoring of minimum throughput

Description

Tank level point detection

Requirements

  • Risk of overfill or dry run
  • Ensure continuous supply of crude oil or refined product

Description

Supervisory and validation software

Requirements

  • Visualisation and monitoring of critical processes
  • Control of reporting, trends and alarm handling
  • Statistical evaluation of measurement data

Description

Metering control cabinets

Requirements

  • Integration of flow computers, PLCs, supervisory computers and printers
  • Installation of single flow computers up to fully redundant cabinet
  • Complying with custody transfer requirements

Description

Sampling and analyser systems

Requirements

  • Measurement of oil and refined product quality
  • Fully automated sampling during loading and unloading
  • Measurement of water content in oil

Description

Provers and master meters

Requirements

  • Fully certified according to local and international metrology requirements
  • Lowest possible measurement uncertainty
  • High reliability and low maintenance

Description

Custody transfer metering systems

Requirements

  • High-accuracy measurement of volume and quality of oil and refined products
  • Traceable to international standards
  • Complying with custody transfer requirements
  • Master/duty configuration with flowmeter diagnostics

Overview

Ship loading in the oil & gas industry

Custody transfer measurement of up and offloading processes

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.

Applications

Custody transfer LNG ship loading and unloading
Application Report | Oil & Gas
  • High accuracy Coriolis mass flow measurement of LNG with a large flowrate
  • Complete custody transfer (CT) measuring system for cryogenic liquids
  • Continuous and consistent measurement results from start to finish even in the event of entrained BOG (Boil-off Gas)
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