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This standard is drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 13611-2006 Classification and Essential Property of City Gas, and the following technical deviations have been made with respect to GB/T 13611-2006 (the previous edition):
— The principle for classification of city gas is modified (see 4.1; 4.1 of Edition 2006);
— The category and characteristic index of city gas are modified (see 4.3; 4.3 of Edition 2006);
— Liquefied petroleum gas and air mixture, dimethyl ether and biogas are added (see 4.3);
— The test gas of city gas is modified (see 4.4; 4.4 of Edition 2006);
— The test pressure of test gas for burning appliances of city gas is added (see 4.5);
— The preparation method of test gas is added (see Annex B);
— The comparison list of BS EN437:1994 and EN 30-1-1:1999 is deleted (see Annex C of Edition 2006).
This standard was proposed and prepared by the Ministry of Housing and Urban-Rural Development of the People's Republic of China.
The previous editions of this standard are as follows:
— GB/T 13611-1992, GB/T 13611-2006.
Classification and Basic Characteristics of City Gas
1 Scope
This standard specifies the principle of classification, calculation methods of characteristic indexes, the requirements of categories and characteristic indexes of city gas, the test gas of city gas, and the test pressure of test gas for burning appliances of city gas.
This standard is applicable to the classification of various gases used as city fuel.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 11062 Natural Gas — Calculation of Calorific Values, Density, Relative Density and Wobbe Index
3 Terms and Definitions
For the purpose of this document, the following terms and definitions apply.
3.1
city gas
common-use fuel gas which meet the standard quality requirements and for the supply of residential, commercial (public) buildings and industrial enterprises.
Note: City gas generally includes manufactured gas, natural gas, liquefied petroleum gas, liquefied petroleum gas mixed air, dimethyl ether gas and biogas.
3.2
reference conditions
dry gas condition at the temperature of 15℃ and absolute pressure of 101.3 kPa
[GB/T 16411-2008, Definition 3.1]
3.3
heating value; calorific value
specified amount of heat released from fuel gas when it is completely burned
Note: Therein, the released heat including the latent heat of vaporization of water vapor in the flue gas is called as high calorific value, and the released heat excluding the latent heat of vaporization of the steam in the flue gas is called as low calorific value.
[GB/T 12206-2006, Definition 3.1, modified]
3.4
relative density; specific gravity
ratio of the mass of a certain volume of dry gas to the mass of dry air of the same volume at the same temperature and pressure
Note: The relative density is a dimensionless quantity, denoted by the symbol d.
[GB/T 12206-2006, Definition 3.5]
3.5
Wobbe number; Wobbe index
ratio of the heat value of gas and the square root of relative density of gas
3.6
reference gas
standard gas representing a certain kind of gas
3.7
limit gas
standard gas prepared according to permissible fluctuation range of gas
4 Principle of Classification
City gas shall be classified according to the gas category and its characteristic index (Wobble number, W), and the fluctuation range of Wobble number (W) and calorific value (H) shall be controlled.
5 Calculation Method of Characteristic Index
5.1 Heating value
The heating value can be calculated by using Equation (1):
(1)
Where:
H — the heating value (classified into high heating value, Hs, and low heating value, Hi) of fuel gas, in megajoules per cubic meter (MJ/m3);
Hr — the heating value of combustible component r in fuel gas, in megajoules per cubic meter (MJ/m3);
fr — the volume fraction of combustible component r in fuel gas, %.
5.2 Relative density
Relative density can be calculated by using Equation (2):
(2)
Where:
d — the relative density of fuel gas (the relative density of air is 1);
dv — the relative density of combustible component v in fuel gas;
fv — the volume fraction of combustible component v in fuel gas, %.
5.3 Wobble number
Wobble number can be calculated by using Equation (3):
(3)
Where:
W — the Wobble number (classified into high Wobble number, Ws, and low Wobble number, Wi) of fuel gas, in megajoules per cubic meter (MJ/m3);
H — the heating value (classified into high heating value, Hs, and low heating value, Hi) of gas, in megajoules per cubic meter (MJ/m3);
d — the relative gas density (the relative air density is 1).
6 Category and Characteristic Index
The categories and characteristic indexes of city gas (15℃, 101.325 kPa, dried) as specified in Table 1.
Foreword II
1 Scope
2 Normative References
3 Terms and Definitions
4 Principle of Classification
5 Calculation Method of Characteristic Index
6 Category and Characteristic Index
7 Test Gas
8 Test Gas Pressure of Burning Appliances
Annex A (Normative) Quality and Characteristic Value of Single Gas for Test Gas Preparation
Annex B (Informative) Preparation Method of Test Gas
Bibliography
