LNG CUSTODY TRANSFER HANDBOOK 5Th Edition: 2017 GIIGNL Document Status and Purpose
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LNG CUSTODY TRANSFER HANDBOOK 5th Edition: 2017 GIIGNL Document status and purpose This fifth (2017) edition of the GIIGNL LNG transfer and LNG transfer from an onshore This latest version replaces all previous editions Custody Transfer Handbook reflects GIIGNL’s terminal to small scale LNG carriers. More than of the custody transfer handbook. Please always understanding of best current practice at the pointing at the differences and highlighting the consult the GIIGNL website www.giignl.org to time of publication. points of attention when dealing with these new check for the latest version of this handbook, operations, this fifth version provides answers esp. when referring to a pdf download or a The purpose of this handbook is to serve as a and solutions for setting up (slightly) altered or printout of this handbook reference manual to assist readers to new custody transfer procedures. As a reminder, understand the procedures and equipment (Photo front cover : © Fluxys Belgium – P. Henderyckx) it is not specifically intended to work out available to and used by the members of GIIGNL procedures for overland LNG custody transfer to determine the energy quantity of LNG operations involving LNG trucks, containers or transferred between LNG ships and LNG trains, or for small scale LNG transfer such as terminals. It is neither a standard nor a bunkering or refueling of ships and trucks. For specification. these, kind reference is made to the GIIGNL This handbook is not intended to provide the Retail LNG / LNG as a fuel handbook. reader with a detailed LNG ship-shore custody No proprietary procedure, nor particular transfer procedure as such, but sets out the manufacture of equipment, is recommended or practical issues and requirements to guide and implied suitable for any specific purpose in this facilitate a skilled operator team to work out a handbook. Readers should ensure that they are suitable procedure for a specific LNG ship-shore in possession of the latest information, custody transfer application. standards and specifications for any procedures The fifth version comes as a quick follow-up and and equipment they intend to employ. update of the fourth edition (2015) which GIIGNL, and any of its members, disclaims any provided, for the first time, a useful insight in direct or indirect liability as to information the relatively new (commercial) opportunities contained in this document for any industrial, resulting from the rapidly changing market commercial or other use whatsoever. conditions: new technical solutions and different operations such as partial (un)loading, reloading at LNG import terminals, ship-to-ship LNG GIIGNL - LNG CUSTODY TRANSFER HANDBOOK Fifth edition – version 5.0 – Uncontrolled when printed 2 Contents 1. Introduction .......................................................................................... 7 3.2. INSTRUMENTS AND METHODS FOR MEASURING THE LEVEL OF LIQUID IN THE LNG CARRIER'S TANKS ............................................................................................ 25 2. General description of the measurement .......................................... 11 3.2.1. Main liquid level gauging devices ............................................................ 25 2.1. GENERAL FORMULA FOR CALCULATING THE LNG ENERGY TRANSFERRED ..... 11 3.2.2. Timing of the level measurement ............................................................ 27 2.2. GENERAL SCHEME OF THE MEASUREMENT OPERATIONS .............................. 12 3.2.3. Readings ................................................................................................... 27 2.2.1. LNG Volume .............................................................................................. 13 3.2.4. Correction of readings ............................................................................. 28 2.2.2. LNG Density .............................................................................................. 14 3.2.5. Use of spare level gauge .......................................................................... 32 2.2.3. LNG Gross calorific value .......................................................................... 14 3.2.6. Complete unloading (tank stripping) ....................................................... 32 2.2.4. Energy of the gas displaced by the transfer of LNG ................................. 14 3.2.7. Automated systems ................................................................................. 33 2.3. INSTRUMENTS USED ........................................................................................ 16 3.3. CALCULATION OF THE VOLUME OF LNG TRANSFERRED ................................. 34 2.3.1. For the determination of the LNG volume ............................................... 16 2.3.2. For the determination of LNG density and gross calorific value .............. 16 4. Temperature measurement ................................................................ 36 2.3.3. For the determination of the energy of displaced gas ............................. 17 4.1. LIQUID TEMPERATURE .................................................................................... 36 2.3.4. For the determination of the energy of “Gas to engine room” ................ 17 4.1.1. Device ....................................................................................................... 36 2.3.5. Periodic instruments recalibration ........................................................... 18 4.1.2. Testing and accuracy ................................................................................ 36 2.4. STANDARDIZATION .......................................................................................... 18 4.2. VAPOR TEMPERATURE .................................................................................... 37 2.5. PARTIAL LOADING OR UNLOADING OF LNG CARRIERS ................................... 18 5. Vapor pressure .................................................................................... 38 2.6. Gassing-up and cooling down operations ........................................................ 18 2.6.1. Gassing-up operations .............................................................................. 18 6. Sampling of LNG .................................................................................. 39 2.6.2. Cooling down operations .......................................................................... 19 6.1. LNG SAMPLING PRINCIPLES ............................................................................ 39 3. Volume measurement ........................................................................ 22 6.2. SAMPLING POINT ............................................................................................ 40 6.3. SAMPLING PROBES .......................................................................................... 41 3.1. GAUGE TABLES ................................................................................................. 22 6.4. PIPING ARRANGEMENT BETWEEN SAMPLING PROBE AND VAPORIZER ........ 42 3.1.1. Use of gauge tables .................................................................................. 22 6.5. LNG VAPORIZER AND CONTROL DEVICES ....................................................... 42 3.1.2. Correction tables ...................................................................................... 22 6.5.1. Main devices ............................................................................................ 42 6.5.2. Auxiliary vaporization control devices ..................................................... 45 3.1.3. Approval by authorities ............................................................................ 23 6.5.3. Operating parameters .............................................................................. 46 GIIGNL - LNG CUSTODY TRANSFER HANDBOOK Fifth edition – version 5.0 – Uncontrolled when printed 3 Contents 6.5.4. Gas sample collection systems ................................................................. 46 8.2. DATA HANDLING: QUALITY ............................................................................. 60 6.6. GAS SAMPLE CONDITIONING ........................................................................... 47 8.2.1. Data processing ........................................................................................ 60 6.6.1. Gas sample containers .............................................................................. 47 8.2.2. Data treatment ........................................................................................ 61 6.6.2. Direct piping to a gas analyzer .................................................................. 47 9. Density ................................................................................................. 62 6.6.3. Examples ................................................................................................... 47 9.1. GENERAL.......................................................................................................... 62 6.7. PERFORMANCE OF THE DEVICES ..................................................................... 51 9.2. DENSITY CALCULATION METHODS .................................................................. 62 6.8. SAMPLING PROCEDURE ................................................................................... 51 9.3. REVISED KLOSEK-Mc KINLEY METHOD ............................................................ 63 6.8.1. Sampling period .......................................................................................