Tests in the Gas Quality Measurement Laboratory

Requirements concerning the quality of natural gas for transmission

Requirements concerning the quality of natural gas for transmission

Item

Unit

System

natural gas grade E natural gas grade Lw
min. gross calorific value

MJ/m3

38,0

30,0

kWh/m3

10,556

8,333

range of the Wobbe index variability

MJ/m3

45,0 - 56,9

37,5 - 45,0

kWh/m3

12,500 - 15,806

10,417 - 12,500

hydrogen sulphide content

mg/m3

≤ 7,0

oxygen content

% mol/mol

≤ 0,2

carbon dioxide content

% mol/mol

≤ 3,0

mercury fumes content

µg/m3

≤ 30,0

water dew point temperature for the pressure of 5.5 MPa from 1 April to 30 September

ºC

≤ +3,7

water dew point temperature for 5.5 MPa from 1 October to 31 March

ºC

≤ -5,0

hydrocarbon dew point

ºC

0

dust content  - particle diameter greater than 5 μm

mg/m3

≤ 1,0

mercaptan sulphur content

mg/m3

≤ 16,0

total sulphur content

mg/m3

≤ 40,0

range of the temperature variability of gaseous fuels introduced to the transmission system

ºC

0 - 50

Except for the water dew point temperatures, all values in the table refer to normal conditions.
- pressure equal to atmospheric pressure – 101.325 kPa
- temperature – 273,15 K (0ºC)

According to point 3.3.4 of the current TNC, the minimum gross calorific value of gaseous fuel introduced to the transmission system is:
- Hs = 34 MJ/m3 (9.444 kWh/m3) for group E high-methane gas system,
- Hs = 30 MJ/m3(8.333 kWh/m3) for the Lw group low-methane gas system.