SAE J 2645-2003 液化天然气（LNG）汽车计量系统.pdf

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TO PLACE A DOCUMENT ORDERTel 877-606-7323 inside USA and Canada Tel 724-776-4970 outside USA Fax 724-776-0790 Email custsvcsae.org SAE WEB ADDRESShttp//www.sae.org SURFACE VEHICLE RECOMMENDED PRACTICE j2645 ISSUED MAR2003 Issued2003-03 Liquefied Natural Gas LNG Vehicle Metering and Dispensing Systems TABLE OF CONTENTS 1Scope/Purpose......................................................................................................................................... 2 2References............................................................................................................................................... 2 2.1Applicable Documents..............................................................................................................................2 2.1.1NIST Publication ...................................................................................................................................... 2 2.1.2NFPA Publications .................................................................................................................................. 2 2.2Related Publications................................................................................................................................. 3 2.2.1State of California Publications................................................................................................................. 3 2.1.2NFPA Publications ................................................................................................................................... 3 3Definitions.................................................................................................................................................3 3.1Authority Having Jurisdiction.................................................................................................................... 3 3.2Contract Sale ............................................................................................................................................ 3 3.3Cryogenic Liquids ..................................................................................................................................... 3 3.4Direct Sale................................................................................................................................................ 3 3.5Dispenser.................................................................................................................................................3 3.6Liquefied Natural Gas LNG.................................................................................................................... 3 3.7Mass Flow Meter ...................................................................................................................................... 3 3.8NBP.......................................................................................................................................................... 3 3.9NTP .......................................................................................................................................................... 3 3.10Point of Sale System................................................................................................................................ 3 3.11Retail Device ............................................................................................................................................ 4 3.12Saturation Pressure.................................................................................................................................. 4 3.13Two-Phase Flow.......................................................................................................................................4 3.14Wholesale Device..................................................................................................................................... 4 4Cryogenic Issues...................................................................................................................................... 4 4.1Heat.......................................................................................................................................................... 4 4.2Saturation Pressure.................................................................................................................................. 4 4.3Density .....................................................................................................................................................4 4.4LNG Composition ..................................................................................................................................... 4 4.5Sub-Cooling..............................................................................................................................................4 SAE j2645 Issued MAR2003 -2- 5Dispensing System Issues........................................................................................................................4 5.1Hose Volume Corrections.........................................................................................................................4 5.2Two-Phase Flow .......................................................................................................................................5 5.3Temperature Effects .................................................................................................................................5 5.4Pressure Effects .......................................................................................................................................5 5.5Composition Compensation......................................................................................................................5 5.6Diversion of Measured Flow .....................................................................................................................5 5.7Vapor Equalization Line............................................................................................................................5 6Dispensing System Selection...................................................................................................................5 6.1Private Stations.........................................................................................................................................5 6.2Public Retail Stations .............................................................................................................................5 6.3Refueling Frequency.................................................................................................................................5 6.3.1All Vehicles Fuel During the Same “Fueling Window” ..............................................................................5 6.3.2Intermittent Fueling ...................................................................................................................................6 7Measurement Device Types .....................................................................................................................6 7.1Volumetric.................................................................................................................................................6 7.2Mass .........................................................................................................................................................6 7.3Inferred Mass............................................................................................................................................6 8LNG Dispenser/Meter ...............................................................................................................................6 9Safe Operation..........................................................................................................................................6 9.1General .....................................................................................................................................................6 9.2Hose Breakaway.......................................................................................................................................7 9.3Connectors ...............................................................................................................................................7 9.4Grounding.................................................................................................................................................7 9.5Venting......................................................................................................................................................7 10Dispenser Display .....................................................................................................................................7 1.ScopeThis SAE Recommended Practice applies to Liquefied Natural Gas Vehicle Fuel. The purpose of this document is to provide ination on issues that are important to consider regarding LNG metering and dispensing systems. 2.References 2.1Applicable PublicationsThe following publications a part of this specification to the extent specified herein. Unless otherwise specified, the latest issue of each publication applies. 2.1.1NIST PUBLICATIONAvailable from the National Institute of Standards and Technology, US Department of Commerce, Gaithersburg, MD 20899-2350, Phone 301-975-3058, www.nist.gov. NIST Handbook 44Specifications, Tolerances, and other Technical Requirements for Weighing and Measuring Devices 2.1.2NFPA PUBLICATIONSAvailable from the National Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101, Quincy, MA 02269-9101, 1-800-344-3555 or http//catalog.nfpa.org. NFPA 52Compressed Natural Gas CNG Vehicular Fuel Systems Code NFPA 57Liquefied Natural Gas LNG Vehicular Fuel Systems Code NFPA 59AStandard for the Production, Storage, and Handling of Liquefied Natural Gas LNG SAE j2645 Issued MAR2003 -3- 2.2Related PublicationsThe following publications are provided for ination purposes only and are not a required part of the document. 2.2.1STATE OF CALIFORNIA PUBLICATIONSAvailable on the web at http//www.dir.ca.gov/Title8/sub1.html. California Code of Regulations CCR, Title 8, Industrial Regulations, Article 7, Compressed and Liquefied Natural Gas Systems 2.2.2NFPA PUBLICATIONSAvailable from the National Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101, Quincy, MA 02269-9101, 1-800-344-3555 or http//catalog.nfpa.org. NFPA 30Flammable and Combustible Liquids Code NFPA 30ACode for Motor Fuel Dispensing Facilities and Repair Garages NFPA 70National Electrical Code NFPA 72National Fire Alarm Code NFPA 79Electrical Standard for Industrial Machinery NFPA 497Classification of Flammable Liquids, Gases, or Vapors and of Hazardous Locations for Electrical Installations in Chemical Process Areas 3.DefinitionsDefinition 3.1 is taken from NFPA 52 Compressed Natural Gas [CNG] Vehicular Fuel Systems Code. Definitions 3.2 to 3.4, 3.7 to 3.10, and 3.14 are taken from NIST Handbook 44 Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices, Appendix D. Definitions 3.5 and 3.11 are based on Handbook 44 definitions. 3.1Authority Having JurisdictionThe organization, office, or individual responsible for approving equipment, an installation, or a procedure. 3.2Contract SaleA sale where there is a written agreement stating the price as either a fixed price, a price above cost, or an adjustment from the posted price. 3.3Cryogenic LiquidsFluids with a normal boiling point below –153 C –243 F. 3.4Direct SaleA sale in which both parties in the transaction are present when the quantity is being determined. An unattended automated or customer-operated weighing or measuring system is considered to represent the device/business owner in transactions involving an unattended device. 3.5DispenserA device designed for the measurement and delivery of fluids used as fuel. 3.6Liquefied Natural Gas LNGA cryogenic liquid, produced by reducing the temperature of natural gas to about –162 C –260 F at atmospheric pressure. 3.7Mass Flow MeterA device that measures the mass of a product flowing through the system. The mass measurement may be determined directly from the effects of mass on the sensing unit or may be inferred by measuring the properties of the product, such as the volume, density, temperature, or pressure, and displaying the quantity in mass units. 3.8NBPNormal boiling point of a cryogenic liquid at 101.325 kPa 14.696 psi absolute. 3.9NTPNormal temperature of 21 C 70 F and pressure of 101.325 kPa 14.696 psi absolute respectively. 3.10Point of Sale SystemAn assembly of elements including a weighing or measuring element, an indicating element, and a recording element and may also be equipped with a “scanner” used to complete a direct sales transaction. SAE j2645 Issued MAR2003 -4- 3.11Retail DeviceA device used for a.Single deliveries of less than 378 L 100 gal or b.Retail deliveries of motor fuels to individual vehicles. 3.12Saturation PressureThe point at which temperature and pressure of a liquid-vapor system are in equilibrium or the pressure at which the liquid will automatically boil. Raise the temperature, and the pressure will rise, lower the pressure and the temperature will fall. As a commonplace example, water will boil at 100 C 212 F at sea level, but will boil at roughly 94 C 202 F in Denver, where there is less air pressure. If a liquid is artificially pressurized, as in a pressure cooker, it will boil at a higher temperature than when in an open pot. Accurate control of the saturation pressure of dispensed LNG may be important because most LNG vehicle systems presently in use rely on this pressure to drive fuel to the engine. 3.13Two-Phase FlowA condition where the liquid is not in a compressed liquid state, but contains some percentage of gas entrained in the flowing liquid. 3.14Wholesale DeviceAny device other than a retail device see