This standard specifies the technical requirements and test methods for compressed natural gas for vehicles. This standard applies to compressed natural gas with a pressure not exceeding 25MPa used as vehicle fuel. GB 18047-2000 Compressed Natural Gas for Vehicles GB18047-2000 Standard download decompression password: www.bzxz.net

GB18047—2000
This standard is based on SY/T7546—1996 "Compressed Natural Gas for Vehicles", refers to ISO/FDIS15403:1998 "Natural Gas - Quality Indicators of Natural Gas as Compressed Fuel for Vehicles" and its draft technical report "Composition Requirements of Natural Gas", and combines the experience of compressed natural gas filling stations and compressed natural gas vehicles in my country in recent years to specify the technical requirements for compressed natural gas for vehicles. SY/T7546—1996 shall be abolished from the date of implementation of this standard. Appendix A and Appendix B of this standard are reminder appendices. This standard is proposed by China National Petroleum Corporation. This standard is under the jurisdiction of the National Natural Gas Standardization Technical Committee. The drafting units of this standard are the Natural Gas Research Institute of Sichuan Petroleum Administration Bureau of China National Petroleum Corporation and the East China Survey and Design Institute of China National Petroleum Corporation.
The main drafters of this standard are Chen Guangliang, Tang Meng, He Yongming, Li Yushan, and Chi Yongjie. I
1 Scope
National Standard of the People's Republic of China
Compressed natural gas as vehicle fuel
Compressed natural gas as vehicle fuel This standard specifies the technical requirements and test methods for compressed natural gas as vehicle fuel. This standard applies to compressed natural gas as vehicle fuel with a pressure not exceeding 25MPa. 2 Referenced standards
GB18047—2000
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T11060.1—1998 Determination of hydrogen sulfide content in natural gas-Iodometric method GB/T11061—1997 Determination of total sulfur in natural gas-Oxidative microcoulometry GB/T11062—1998 Calculation method for calorific value, density, relative density and Wobbe index of natural gas GB/T13609—1999 Guidelines for sampling of natural gas Composition analysis of natural gas Phase chromatography
GB/T136101992
GB17258—1998 Compressed natural gas cylinders for vehiclesGB/T17283—1998
Determination of water dew point of natural gas
Cooled mirror condensation hygrometer methodwww.bzxz.net
Safety supervision regulations for gas cylinders
Safety technical supervision regulations for pressure vessels
3 Definitions
This standard adopts the following definitions.
3.1 Compressed natural gas CNGcompressed natural gas Compressed gas fuel with methane as the main component. 3.2 Compressed natural gas for vehicles compressed natural gas as vehicle fuel Compressed natural gas stored in special pressure vessels and used as vehicle fuel. 4 Technical requirements and test methods
4.1 The technical indicators of compressed natural gas shall comply with the provisions of Table 1. 4.2 The calculation of high calorific value of natural gas shall be carried out in accordance with GB/T11062, and the determination of natural gas composition based on it shall be carried out in accordance with GB/T13610.
4.3 The determination of total sulfur content in natural gas shall be carried out in accordance with GB/T11061. 4.4 The determination of hydrogen sulfide content in natural gas shall be carried out in accordance with GB/T11060.1. 4.5 The determination of carbon dioxide content in natural gas shall be carried out in accordance with GB/T13610. 4.6 The determination of oxygen in natural gas shall be carried out in accordance with GB/T13610. 4.7 The determination of water dew point of natural gas shall be carried out in accordance with GB/T17283. State Administration of Quality and Technical Supervision, approved on April 3, 2000, implemented on July 1, 2000
High calorific value, MJ/m3
Total sulfur (in terms of sulfur), mg/m
Hydrogen sulfide, mg/m
Carbon dioxide gcoz, %
Oxygen 02.%
Water dew point, ℃
GB 18047—2000
Table 1 Technical indicators of compressed natural gas
Technical indicators
In the specific geographical area where the car is driven, at the highest operating pressure, the water dew point should not be higher than -13℃. When the minimum temperature is below -8℃, the water dew point should be 5℃ lower than the minimum temperature. Note: The standard reference condition for gas volume in this standard is 101.325kPa, 20℃5 Storage and use
5.1 The storage container of compressed natural gas shall comply with the relevant provisions of the current "Regulations on Safety Technical Supervision of Pressure Vessels" and "Regulations on Safety Supervision of Gas Cylinders". Compressed natural gas cylinders shall comply with the relevant provisions of GB17258 "Compressed Natural Gas Cylinders for Automobiles". 5.2 At the operating pressure and temperature, there should be no liquid hydrocarbons in compressed natural gas. 5.3 The diameter of solid particles in compressed natural gas should be less than 5μm. 5.4 Compressed natural gas should have a perceptible odor. Natural gas with no odor or insufficient odor should be odorized. The minimum amount of odorant should be sufficient to meet the requirement that when natural gas leaks into the air and reaches a concentration of 20% of the lower explosion limit, it should be detectable. Odorants are usually prepared with mercaptans, sulfides or other sulfur-containing organic compounds with obvious odors.
5.5 When using compressed natural gas for vehicles, its anti-explosion performance should be considered. Appendix A gives the calculation method of the methane value of natural gas. 5.6 When using compressed natural gas for vehicles, its Wobbe index (Wobbe number) should be considered. The gas category of compressed natural gas from each gas station with the same gas source should remain unchanged. Appendix B gives the gas category of compressed natural gas. 6 Inspection
6.1 Sampling of compressed natural gas for vehicles shall be carried out in accordance with GB/T13609. 6.2 During normal production, the product water dew point must be inspected regularly to ensure that there is no liquid water in the compressed natural gas. 6.3 Under the following circumstances, compressed natural gas products for automobiles shall be fully inspected in accordance with the technical requirements specified in this standard: a) when first put into production;
b) during normal production, periodically or after accumulating a certain amount of output; c) when the inspection result is significantly different from the last comprehensive inspection. 2
A1 Definition of methane number
Methane number MNmethanenumber
GB18047—2000
Appendix A
(Suggestive Appendix)
Calculation method of methane number
An agreed value indicating the anti-knock property of spark-ignition engine fuel. The methane number of a gas fuel is determined by comparing the knock tendency of the fuel with that of a standard fuel mixture in a standard engine test under specified conditions using the ASTM octane number evaluation method. When the anti-knock performance of the tested gas fuel is the same as that of the standard fuel of methane and hydrogen mixed in a certain proportion, the value of the volume percentage of methane in the standard fuel is the methane number of the gas fuel.
A2 Octane number and methane number
ISO/FDIS154031998 Appendix D "Methane number and octane number" points out that the Gas Research Institute (GRI) of the United States measured the motor octane number (MON) of natural gas fuel using the ASTM octane number evaluation method. The measurement results show that the MON of pure methane is around 140, and the MON of most natural gases is between 115130. The MON of peak-shaving gas with a high propane content (17% to 25%) is 96 to 97. Through research, the Gas Research Institute of the United States has derived two correlation formulas between composition or hydrogen-carbon ratio and octane number that are very consistent with experimental data and can be applied to most conventional natural gases. In addition, there are two correlation formulas between octane number and methane number derived from experimental data. These correlations are as follows: A2.1 Linear correlation between natural gas composition and octane number: MON-137.78r1+29.948x2-18.193-167.062+181.233+26.994 Where: MON-motor octane number;
-molar fraction of component, the code and name of each component are shown in Table A1. Table A1 Component codes and names in gas fuel Component code
Component name
A2.2 Correlation between natural gas hydrogen-carbon ratio and octane number: 3
Carbon dioxide
MON=-406.14+508.04R-173.55R2+20.17R3 Where: R-
-ratio of hydrogen atoms to carbon atoms in gas fuel. A2.3 The correlation between the methane number and the octane number of natural gas: MN-1.445MON-103.42
MON =0.679MN+72.3
.*..(Al)
-（A3）
（A4）
Formula (A3) and formula (A4) are not completely linear (2=0.98), therefore, these two correlations are not completely reversible. GB18047—2000
Appendix B
(Suggestive Appendix)
Gas categories of compressed natural gas
According to GB/T13611—1992 "City Gas Classification", and in combination with the requirement of natural gas high calorific value greater than 31.4MJ/m in the technical indicators of this standard, compressed natural gas can be divided into three categories: 10T, 12T and 13T according to the range of Wobbe index (Wobbe number) W, see Table Bl.
The Wobbe index (Wobbe number) W (wobbeindex)) is calculated according to formula (B1): W=
W-
-Wobbe index (Wobbe number) of gas, MJ/m; H. Volume high calorific value of gas, MJ/m\, H
-Relative density of gas (relative density of air is 1). d
Table B1 Gas categories of compressed natural gas
Nominal value
·(B1)
(dry, 20℃, 101.325kPa)
Wobbe index W, MJ/m
38.3~44.0
44.7~53.7
50.5~54.7
Note: The value of the Wobbe index in the table is based on the Wobbe index at 0℃, 101.3kPa given in GB/T13611-1992, and is converted according to the formula given in IS013443:1996. The conversion factor is 0.92963
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