User’s Handbook, TSL 4230, Issue 4
41
5
4016-E61TRS
Gas and engine fluids specification
5
Gas specification
A new engine will be set to operate on clean natural gas conforming to the British natural gas specifications
having a lower calorific value of 34,71 MJ/Sm
3
(930 BTU/Sft
3
).
The difference between high calorific value (HCV) and low calorific (LCV) is that (HCV) is the total amount of
heat given off by the gas during combustion and the (LCV) is the high calorific value less the amount of heat
used to vaporize the water content of the gas. Since the amount of heat lost in vaporizing the water is different
for different gases, the lower calorific value of the gas is chosen as the basis for fuel consumption data. There
must be no liquid hydrocarbon fractions in the gas.
Note: The rating may be reduced if lower calorific value of the fuel is lower than 34,71 MJ/Nm
3
(930 BTU/Sft
3
).
Also pressure must be constant to maintain emissions and stability. If any of the above parameters are not
met, Perkins Engines Company Limited should be consulted for advice.
Gas safety regulations
There are legal requirements that within the U.K. gas fittings and equipment must be installed only by
competent persons and in accordance with the Institution of Gas Engineers Procedures IGE UP2. Outside the
U.K. anyone undertaking work on the engine or associated with the engine and its gas equipment in particular
should check with local and national regulations to ensure compliance.
Limiting values for British Gas
Methane number must exceed
75
Combustible constituents must exceed
95%
Calorific value (LCV) to exceed
34 MJ/Nm
3
(912 BTU/Sft
3
)
Ethane
4.5%
Hydrogen content not to exceed
0.1%
Propane must not exceed
1.0%
Isobutane content not to exceed
0.2%
Normal butane not to exceed
0.2%
Normal pentane and higher fractions (hexane, heptane, etc).
The summation must not exceed
0.02%
Minimum gas pressure at inlet to regulators
15 mbar (1.5 kPa)
Gas pressure not to exceed, without additional pressure regulators
50 mbar (5 kPa)
Hydrogen sulphide not to exceed
0.01% or 100 ppm
This document has been printed from SPI². Not for Resale