1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2011 SAE International All rights reserved. No part of this publication ma
3、y be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside US
4、A) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J2699_201107SURFACEVEHICLEINFORMATIONREPORTJ2699 JUL2011 Issued 2011-07Liquefied Natural Gas (L
5、NG) Vehicle Fuel RATIONALELiquefied Natural Gas (LNG) is a cryogenic hydrocarbon liquid used as a transportation fuel and by its very nature as a cryogen changes in composition as it is transferred from the LNG production facility to fueling station and then to the vehicles fuel storage system. At p
6、resent there are no guidelines that can help the industry manage the change in composition of LNG so that the end user receives a fuel that meets the specifications required for proper operation of the vehicle. The time sensitive nature of LNG is unique in the transportation industry and SAE J1616 i
7、s needed to provide a methodology to determine LNG useable lifetime. The only agency in North America that provides a minimum composition level of natural gas vehicles is CARB. This regulation is a Compressed Natural Gas standard and the reference to water, CO2, sulfur, and lubricates which do not a
8、pply to LNG, the hydrocarbon components of natural gas do apply. The minimum level of methane and max levels of ethane, propane, butane, and nitrogen, provide important references for engine manufactures. These minimum and maximum levels of constituents in the fuel composition are crucial in the eng
9、ine design.When using LNG as a vehicle fuel, it is stored at some combination of cryogenic temperature and relatively low pressure. It is not uncommon for the fuel to go through several transfers as it is moved from production site storage, to a transport tank, transport tank to a local refueling st
10、ation tank and then into the vehicle tank. During each transfer, and during periods of storage, heat transfers into the fuel, which if left to evaporate its composition will change.In order to provide fuel to the engine that meets the minimum hydrocarbons requirement of CARB, the LNG vaporization mu
11、st be controlled and LNG inventories must be managed. Therefore, this document includes the information required to calculate a “dispense by” date for LNG. With a fixed set of assumptions on evaporation rates, a known initial fuel composition, the future fuel composition can be calculated. While thi
12、s document is based on CARB requirements, the same methodology can be used for different fuel composition targets were required.The purpose of this document is to provide the fixed assumption and calculation so that LNG producers can provide the require product information data which fuel compositio
13、n and its “dispense by” dates can be calculated. The “dispense by” date provides users the date when the fuel no longer meets the minimum hydrocarbon requirement of CARB, which may compromise the engine emission performance, warranty or reliability. The “dispense by” date provides users the time/dat
14、e when the fuel meets the minimum hydrocarbon requirement of CARB. Beyond this date/time the fuel composition may compromise engine emission performance, warranty or reliability. SAE J2699 Issued JUL2011 Page 2 of 16 FOREWORDLiquefied natural gas (LNG) is a practical automotive fuel with advantages
15、and disadvantages when compared to conventional liquid fuels. Large quantities of natural gas are produced in North America. It has a higher “octane” rating, provides lower exhaust emissions of criteria (and many other) pollutants, and can cost less on an equivalent energy basis than other fuels.LNG
16、 is a cryogenic liquid, which is produced by removing heat from natural gas. As heat is removed, the vapor cools and condenses, resulting in a liquid product with a boiling point of about 162 C (260 F) at atmospheric pressure. Liquefaction increases the energy density of natural gas, thereby reducin
17、g its on-board vehicle storage volume for a given range and payload. Typical pipeline natural gas and compressed natural gas is chiefly methane (generally 88 to 96 mole percent) with the balance being a decreasing proportion of higher hydrocarbons such as ethane, propane, and butane. It can also con
18、tain nitrogen, water, carbon dioxide, oxygen, sulfur compounds and trace amounts of lubricating oil. The composition of LNG is different from that of pipeline natural gas as a result of the liquefaction process. Most of the hydrocarbon constituents remain soluble in LNG. However, other components, s
19、uch as water, carbon dioxide, sulfur compounds and trace amounts of lubricating oil are be removed during the liquefaction process.At present the only agency in North America which provides a minimum composition level of natural gas vehicles is CARB. This regulation is a Compressed Natural Gas stand
20、ard and the reference to water, CO2, sulfur, and lubricates which do not apply to LNG, the hydrocarbon components of natural gas do apply. The minimum level of methane and max levels of ethane, propane, butane, and nitrogen, provide important references for engine manufactures. These minimum and max
21、imum levels of constituents in the fuel composition are crucial in the engine design.When using LNG as a vehicle fuel, it is stored at some combination of cryogenic temperature and relatively low pressure. It is not uncommon for the fuel to go through several transfers as it is moved from production
22、 site storage, to a transport tank, transport tank to a local refueling station tank and then into the vehicle tank. During each transfer, and during periods of storage, heat transfers into the fuel, which if left to evaporate its composition will change.In order to provide fuel to the engine that m
23、eets the minimum hydrocarbons requirement of CARB, the LNG vaporization must be controlled and LNG inventories must be managed. Therefore, this document includes the information required to calculate a “dispense by” date for LNG. With a fixed set of assumptions on evaporation rates, a known initial
24、fuel composition, the future fuel composition can be calculated. While this document is based on CARB requirements, the same methodology can be used for different fuel composition targets were required.SAE J2699 Issued JUL2011 Page 3 of 16 TABLE OF CONTENTS 1. SCOPE 51.1 Purpose . 52. REFERENCES 52.
25、1 Applicable Document 52.1.1 State of California Publication . 52.2 Related Publications . 52.2.1 SAE Publications . 52.2.2 NFPA Publications 53. DEFINITIONS . 63.1 CRYOGENIC LIQUIDS . 63.2 FUEL MOLE PERCENT . 63.3 LIQUEFIED NATURAL GAS (LNG) 63.4 METHANE NUMBER 63.5 STANDARD GAS VOLUME PERCENTAGE .
26、 63.6 DISPENSE BY DATE 63.7 WEATHERING 64. ENGINE MANUFACTURERS NATURAL GAS COMPOSITION REQUIREMENTS 64.1 Engine Tolerance 65. CARB (CALIFORNIA AIR RESOURCES BOARD) COMMERCIAL CNG REQUIREMENTS . 76. LNG PROPERTIES . 86.1 Fuel Density as it Relates to Storage . 86.2 Saturation Pressure as it Relates
27、to Temperature . 86.3 Weathering 97. LNG BULK TRANSPORTERS AND LNG PRODUCTION FACILITY REQUIREMENTS 97.1 “Dispense by” Date Assumptions . 107.1.1 Evaporation Rate 107.1.2 Vehicle Usage. 107.1.3 Normal Product Transfer . 107.2 “Dispense by” Date Charts 117.2.1 Methane/Time Composition Chart 117.2.2 E
28、thane/Time Composition Chart . 127.2.3 C3-C5/Time Composition Chart 137.2.4 C6+/Time Composition Chart . 147.3 Lubricity . 147.4 Nitrogen Limits 147.5 Particulate Matter 147.6 Odorant . 148. RECOMMENDATIONS FOR LNG FUELING STATION AND LNG VEHICLE OPERATORS . 158.1 LNG Station Operators . 158.2 LNG V
29、ehicle Operators . 158.3 High-Nitrogen LNG . 169. NOTES 169.1 Marginal Indicia . 16SAE J2699 Issued JUL2011 Page 4 of 16 FIGURE 1 LNG PRESSURE VERSUS DENSITY . 8FIGURE 2 LNG PRESSURE VERSUS TEMPERATURE 9FIGURE 3 METHANE MOLE FRACTION VERSUS TIME 11FIGURE 4 ETHANE MOLE FRACTION VERSUS TIME . 12FIGURE
30、 5 C3-C5 MOLE FRACTION VERSUS TIME . 13FIGURE 6 C6+ MOLE FRACTION VERSUS TIME . 14TABLE 1 CARB COMMERCIAL CNG REQUIREMENTS (1/1/1993) 7TABLE 2 SOURCE FUEL COMPOSITIONS . 10SAE J2699 Issued JUL2011 Page 5 of 16 1. SCOPE This SAE Information Report applies to liquefied natural gas used as vehicle fuel
31、 and requires LNG producers to provide the required information on the fuel composition and its “dispense by” date.1.1 Purpose The purpose of this document is to provide the fixed assumption and calculation so that LNG producers can provide the require product information data which fuel composition
32、 and its “dispense by” dates can be calculated. The “dispense by” date provides users the date when the fuel no longer meets the minimum hydrocarbon requirement of CARB, which may compromise the engine emission performance, warranty or reliability. The “dispense by” date provides users the time/date
33、 when the fuel meets the minimum hydrocarbon requirement of CARB. Beyond this date/time the fuel composition may compromise engine emission performance, warranty or reliability. 2. REFERENCES 2.1 Applicable Document The following publication forms a part of this specification to the extent specified
34、 herein. Unless otherwise indicated, the latest issue of SAE publications shall apply. 2.1.1 State of California Publication Available from website http:/ccr.oal.ca.gov/.Specifications for Compressed Natural Gas, California Air Resources Board, Title 13, Division 3, Chapter 5, Article 3, Section 229
35、2.5 of the California Code of Regulations 2.2 Related Publications The following publications are provided for information purposes only and are not a required part of this SAE Technical Report.2.2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001
36、, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.SAE J2343 Recommended Practice for LNG Medium and Heavy-Duty Powered Vehicles 2.2.2 NFPA Publications Available from the National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471, Tel: 800-3
37、44-3555, www.nfpa.org.NFPA 52 2006 Vehicular Fuel System Code NFPA 59A 2006 Standard for the Production, Storage, and Handling of Liquefied Natural Gas SAE J2699 Issued JUL2011 Page 6 of 16 3. DEFINITIONS 3.1 CRYOGENIC LIQUIDS Fluids with a normal boiling point below 153 C (243 F). 3.2 FUEL MOLE PER
38、CENT The number of moles of the constituent in one mole of the gas mixture, multiplied by 100. The mole percentage is equal to the volume percentage. 3.3 LIQUEFIED NATURAL GAS (LNG) A cryogenic liquid, produced by reducing the temperature of natural gas to about 162 C (260 F) at atmospheric pressure
39、.3.4 METHANE NUMBER A measure of the knock resistance of natural gas used in an internal combustion engine. A methane number of 100 represents the knock resistance of pure methane, and is approximately equal to a motor octane number of 140. Presence of higher hydrocarbons in the fuel tends to reduce
40、 the methane number and thereby its knock resistance. 3.5 STANDARD GAS VOLUME PERCENTAGE The volume fraction of a gas constituent at standard conditions, multiplied by 100. Commonly used by the gas industry. 3.6 DISPENSE BY DATE The last date at which a given composition of fuel meets California Air
41、 Resources Board specification. 3.7 WEATHERING A change in the constituent composition of the cryogenic fluid mixture remaining in the tank, as ambient heat transfers into the tank and gas vapor of different composition is released to control the tank pressure. 4. ENGINE MANUFACTURERS NATURAL GAS CO
42、MPOSITION REQUIREMENTS Major engine manufacturers that currently sell engines that operate on Natural Gas have designed those engines to operate on wide range of fuel compositions. However, in North America the only jurisdiction that has a related Natural Gas composition requirement is California Ai
43、r Resources Board (Section 5). While this requirement is for CNG, the combustion and emission characteristics of LNG and CNG are the same.4.1 Engine Tolerance Older natural gas engines are much more sensitive to changes in fuel composition than newer engines, which use knock, exhaust gas composition
44、 and other sensors to modify spark timing, air-fuel ratio and other engine parameters in closed-loop fashion. Because the older “open loop” engines had no means to compensate for significant changes in fuel composition, such changes would likely affect engine power, emissions, durability, and fuel e
45、conomy. Most importantly, fuels with increased proportions of “higher hydrocarbons” (such as ethane, propane and butane) have a lower methane number (or octane number) than high-methane fuels. Open loop engines designed to run on high methane number fuel can suffer detonation (engine knock) on a low
46、er methane number fuel. Just as in high-compression gasoline engines forced to run on a lower octane fuel, such engines can suffer severe physical damage. Closed-loop operation and knock sensors allow engines to adapt to a much wider range of fuel without damage and without significantly affecting p
47、erformance or emissions. Therefore users of older or open-loop engine designs need to be sure their engines are fueled with natural gas of the proper composition, or alternatively, the engines controls are properly calibrated for the fuel being used.SAE J2699 Issued JUL2011 Page 7 of 16 5. CARB (CAL
48、IFORNIA AIR RESOURCES BOARD) COMMERCIAL CNG REQUIREMENTS The only U.S. regulatory requirements for vehicular natural gas sold commercially are the Specifications for Compressed Natural Gas set forth by the California Air Resources Board in Title 13, Division 3, Chapter 5, Article 3, Section 2292.5 o
49、f the California Code of Regulations (See 2). These are requirements for Compressed (not Liquefied) Natural Gas. Since natural gas engines are normally designed to be fueled by either CNG or LNG, these specifications for vehicular natural gas may be of interest. Natural gas inducted into the engine, whether stored on board as CNG or LNG, should be acceptable to all engine manufacturers if it meets or exceeds the CARB specific
