PRODUCT INFORMATION
INDEX
DATE
Dep. 8
IC-G-D-30-021e
B
May 2014
FUEL SPECIFICATIONS – US NATURAL GAS
3/5
2.3.5. HIGHER HYDROCARBONS IN GAS
The maximum permissible quantity of C4+ hydrocarbons (butane and higher) shall not exceed 2% of the total
gas mixture volume. For greater percentages, contact Kohler .
Therefore, we recommend that gas is fed to the engine at a temperature exceeding the gas dew point by at least
15ºC.
2.4. CONTAMINANTS OF FUEL GAS
Listed below are the maximum permissible values of the contaminants that are normally found in natural gas used
as fuel in Kohler engines. The stated limits may not be exceeded; neither are contaminants - other than those
listed below - allowed in the fuel gas.
2.4.1. SULFUR COMPOUNDS STATED AS H
2
S.
For Kohler engines, the maximum permissible limit of H
2
S equivalent* is set at:
300 ppm ---- 455 mg /m
n
3
ENGINES WITHOUT CATALYTIC CONVERTER
100 ppm------- 150 mg /m
n
3
ENGINES WITH A CATALYTIC CONVERTER
*: In order to calculate the H
2
S equivalent in other sulfur compounds, the mass of S present in the sulfur
compound may be taken as a basis for the mass of H
2
S, considering organic and inorganic compounds.
2.4.2. HALOGENATED COMPOUNDS ( F, Cl, Br, I ) STATED AS Cl
-
HF and HCl are the most harmful acids; therefore, their concentration is specified in mg of Cl
–
equivalent /m
n
3
and the remaining constituents are considered as if they were chlorine, using the following equations:
Fluor = 2 Chlorine
Bromine = 0.5 Chlorine
Iodine = 0.25 Chlorine
Accordingly, for Kohler engines, the maximum permissible level of halides, expressed as chloride equivalent, is
set at:
80 ppm ---- 100 mg Cl
-
equivalent* / m
n
3
ENGINES WITHOUT CATALYTIC CONVERTER
6.5 ppm ----8 mg Cl
-
equivalent* / m
n
3
ENGINES WITH A CATALYTIC CONVERTER
*: Organic and inorganic halides must be taken into consideration.
2.4.3. SILICON COMPOUNDS
Kohler has set the maximum permissible content of silicon in a fuel gas at:
7 mg / m
n
3
*
ENGINES WITHOUT CATALYTIC CONVERTER
NIL
ENGINES WITH A CATALYTIC CONVERTER
In calculating the proportion of silicon in siloxanes, it is reasonable to take an average of 37% of silicon per total
siloxanes.
*: Given the difficulties in analyzing and quantifying the silicon compounds in a fuel gas (Contact
Kohler for information on reference laboratories), it is generally agreed that the
silicon content in the oil of the engine should not exceed 75 ppm during the contracted maintenance period of the
engine concerned. Accordingly, this value may also be deemed to be the maximum relative limit of silicon in the
fuel.
4.1.21
O&M_2.002211.810_A_10_2016
