An oil depot in Kowloon, Hong Kong
Tank farm at McMurdo Station, Antarctica

In the petroleum industry, and within the field of process engineering in general, tank gauging refers specifically to static quantity assessment of bulk liquids in storage tanks. The measurement is usually quantified as Net Standard Volume (NSV, e.g. barrel or cubic meter) or Net Standard Weight (NSW, e.g. lb, ton). The output is calculated based on static data (e.g. tank strapping table) combined with volumetric (level and temperature) or mass (differential-pressure) measurements, or a hybrid between the two.

The measured bulk product can in theory be any type of liquid such as chemicals, bio-fuels or water, stored in any type of container such as caverns, marine tankers or pressure vessels. The most frequent application is however liquid petroleum products stored in non-pressurized storage tanks[1]. These tanks are often classified as hazardous areas, and require the installed equipment to be in compliance with EX requirements. Process industry vessels and simple containers do not usually require tank gauging measurements.

Often 'tank gauging' incorrectly denotes the entire 'automatic tank gauging system'(ATGS), but the measurement procedure itself can either be manual, semi-automatic or automatic. High reliability tank gauging data is critical for the operations of a tank farm, and associated legislate requirements and safety aspects. For example, the tank gauging system is usually the primary method of preventing overfills.

Tank gauging data is also often used for fiscal purposes and custody transfers. Therefore the measurement accuracy becomes critical, especially as most bulk liquid transfers represent a large value. A correctly specified value from a tank gauging measurement shall always come with a measurement uncertainty. Tank gauging therefore employs more rigorous measurement procedures and higher accuracy equipment than 'ordinary' sensors within process industry. Re-calibration (or verification) is often an annual requirement, and some countries require national custody transfer certificates. The tank gauging batch data can also be compared with accumulated flow metering data, or tank gauging measurements done by independent surveyors.

What is tank gauging?

edit

Tank Gauge vs. Level Sensor


Storage tank

Why use tank gauging?

edit

Modern tank gauging nsystem control-room with HMI (but not as complicated as a DCS)

Tank gauging data is often used for the following purposes:

  • Oil movement and operations
  • Stock Accounting
  • Operational Control
  • Batch Transfer Handling
  • Overfill Prevention
  • Pump Control
  • Roof Tilt Surveillance
  • Inventory Control
  • Custody Transfer
  • Temperature, pressure, density corrections of observed volume


  • Mass balance/Loss estimation
  • Leak detection
  • Overfill protection

Tank gauging applications

edit
 
Aviation fuel storage tanks at George Bush Intercontinental Airport, Houston, Texas.

Tank gauging can be applied to virtually any liquid stored in a tank; hydrocarbons and other chemicals. The liquid may be heated, chilled, boiling, agitated Heated secondary containment Aboveground storage tanks (AST) differ from underground (UST) storage tanks in the kinds of regulations that are applied. Biofuels such as palm-Oil and bio-diesel

Liquefied gases Natural gas condensate

underground, bullets, Tank blanketing

While steel and concrete remain one of the most popular choices for tanks, glass-reinforced plastic, thermoplastic and polyethylene tanks are increasing in popularity.

  • Tank Terminals




Manual tank gauging measurements

edit

For verification. API 3.1A

Automatic Tank Gauging Systems (ATGS)

edit

These tanks are often classified as hazardous areas, and require the installed equipment to be in compliance with EX requirements.

Lots of requirements, contact expert, usually the bendors.

Automatic Tank Gauge (ATG) Level+temp automatic, density in lab Hybrid measurement API 3.6

Volumetric measurements

edit

Level Sensors

edit

Tank Gauging Level Measurement Sensors by Technology (2012)[2]

  Float & Tape (1.2%)
  Guided Wave Radar (5.9%)
  HTG (23.2%)
  Magnetostrictive (2.5%)
  Non-contacting RADAR (42.6%)
  Servo (20.8%)
  Other (3.8%)


API 3.1B Automatic Tank Gauge (ATG) History from F&T to Servo to Radar

Radar
edit
Servo
edit
Float & Tape
edit

Temperature transmitters

edit

API 7 Multi-Temperature Transmitter (MTT)

Hydrostatic (mass) measurements

edit

HTG

Hybrid measurements

edit

Human to Machine Interface (HMI)

edit

Communication technology

edit

Overfill Prevention System

edit

test 1234


  1. Rosemount Tank gauging, Emerson inc (formerly known as 'Saab Marine Electronics AB')
  2. Honeywell (formerly known as 'Enraf BV')
  3. Endress+Hauser

test 1234

Tank Gauging Calculations

edit

Overview

edit

Calculate the volume correction factors for Petroleum (Crude Oil)Products. Obtain temperature (CTL), pressure (CPL) and combined (CTPL) factors, given a known density, to 60 Deg F and other temperatures and pressures. Calculations are selectable for Crude Oil, Refined Products or Lubricants. Temperature inputs are in Deg F and Deg C. Density inputs are in S.G., API and kg/m3. Pressure inputs are in PSI, bar and kPa. Results are in Deg F, S.G., API, kg/m3, PSI. Will calculate a Base (60 Deg F) density when needed. Product custody transfer, auditing, surveying. Chemical Engineering calculations.

Observed Data

edit

The "observed" condition is the temperature and pressure at which the density of a liquid is actually or assumed to have been measured. Calculations can then be performed to correct this observed density to any other temperature and pressure conditions.

Stilling-well corrections

edit

Level to Volume (strapping tables)

edit

Tank Bulging

Temperature and pressure compensation tables

edit

Temperature Stratification

edit

Net Standard Volume (NSV)

edit

Net Standard Weight (NSW)

edit

Liquefied natural gas (LPG/LNG)

edit

Measurement Accuracy and Custody Transfer

edit

Global accuracy requirements

edit

Typical measurement uncertainty analysis

edit

Custody Transfer Certificates

edit

Factors affecting the accuracy

edit

Flow-meters or tank gauging system?

edit

Health, Safety and Environment (HSE)

edit

Major Accidents

edit

Buncefield, Jaipur

Ofta växer städer så att terminalerna ligger mitt i staden

Overfill Prevention Systems (OPS)

edit

Safety Certificates

edit
Tank Gauging Safety Certificates
Country Description Certifying Body Legislative Requirement Comment


  Belgium Overfill Prevention VLAREM TBD
  Germany tomt Overfill Prevention TÜV/DIBt WHG (Water Resources Act)
  Switzerland Overfill Prevention tomt BAFU BUWAL
  (worldwide) Overfill Prevention tomt BAFU BUWAL


TÜV/DIBt WHG


Similar regulations exist in Belgium and Switzerland. In parts of Belgium it is the VLAREM. You can get further information from AIB Vincotte at www.vincotte.com. In Switzerland the guideline is called BUWAL. The Federal Office for the Environment (BAFU) i

Safety Instrumented Systems (SIS)

edit

Equipment Verification (Proof-testing)

edit

Leak Detection

edit
edit

American Petroleum Institute (API)

edit

API Manual of Petroleum Measurement (MPMS)

3.1B Automatic Tank Gauging 7.3 Temperature Measurements 3.3 LPG Measurements 3.6 Hybrid Measurements 2350 Overfill Protection


International Organization for Standardization (ISO)

edit
edit

OIML R85:2008


IEC 62591 (Wireless HART)

edit

WirelessHART

edit

Overfill prevention

edit

Referens till min egen artikel [3]

  • ATG + independent overfill alarm
  • SIL
  • continuous measurement also for overfill

Wireless Data Communication

edit

Roof Tilt Measurements

edit

Leak Detection

edit
 
Overview picture of a typical independent oil terminal


[Test]

See also

edit


ATG[4]

MTG

HMI + proper measurement equipment


http://www.iec.ch/functionalsafety/ IEC Functional Safety Website


(sometimes called a tank farm, installation or oil terminal) is an industrial facility for the storage of oil and/or petrochemical products and from which these products are usually transported to end users or further storage facilities. An oil depot typically has tankage, either above ground or underground, and gantries for the discharge of products into road tankers or other vehicles (such as barges) or pipelines.

Oil depots are usually situated close to oil refineries or in locations where marine tankers containing products can discharge their cargo. Some depots are attached to pipelines from which they draw their supplies and depots can also be fed by rail, by barge and by road tanker (sometimes known as "bridging").

Most oil depots have road tankers operating from their grounds and these vehicles transport products to petrol stations or other users.

An oil depot is a comparatively unsophisticated facility in that (in most cases) there is no processing or other transformation on site. The products which reach the depot (from a refinery) are in their final form suitable for delivery to customers. In some cases additives may be injected into products in tanks, but there is usually no manufacturing plant on site. Modern depots comprise the same types of tankage, pipelines and gantries as those in the past and although there is a greater degree of automation on site, there have been few significant changes in depot operational activities over time.


Ethnic composition (%) of resident population
Ethnic 1970 1980 1990 2000 2009
Chinese 77.0 78.3 77.7 76.8 74.2
Malays 14.8 14.4 14.1 13.9 13.4
Indians 7.0 6.3 7.1 7.9 9.2
Others 1.2 1.0 1.1 1.4 3.2



Many of the tanks have a floating roof, to minimize product vapor emissions, which needs to be taken into account by the measurement method e.g. through an insert measurement pipe.


simpler than process



[5]

volu vs mass


Most countries regulated



Petroleum

Mass Volumetric


The determination of temperature, API gravity, and suspended sediment and water of the tank contents a

methods used for these

determinations may be found in the API Manual of Petroleum Measurement Standards (MPMS).


List_of_largest_oil_and_gas_companies_by_revenue Marine_transfer_operations

Oil storage Category:Petroleum production Category:Fuel containers



Carl-Johan Roos 21:57, 11 November 2013 (UTC)

References

edit
  1. ^ TBD hitta referens
  2. ^ VDC 2012
  3. ^ The Art of Tank Gauging, Enraf B.V.
  4. ^ The Art of Tank Gauging, Enraf B.V.
  5. ^ The Art of Tank Gauging, Enraf B.V.