Get to know Compressed Natural Gas
Compressed Natural Gas (CNG) is also known as Fuel Gas (BBG). CNG is a fuel derived from compressed natural gas at a storage pressure of 200-248bar and is useful as a substitute for gasoline, diesel, and LPG. CNG fuel still produces CO2 as a result of its combustion, but it is much more environmentally friendly when compared to other fuels. Economically, the use of CNG is also cheaper when compared to other petroleum fuels. On this basis, the Indonesian government is currently actively campaigning for the conversion of motor vehicle fuel to CNG/CNG.
Here are some of the advantages of using CNG as a fuel:
The use of CNG will not cause crust on the combustion chamber / ignitor like the use of gasoline or diesel.
CNG-fueled motorized vehicles have relatively lower maintenance costs than conventional fueled vehicles.
CNG uses a good sealing system, to prevent leakage. So that storage is more efficient due to small losses.
Extends engine oil life because CNG will not contaminate engine oil.
The process of mixing CNG with air is relatively easier because of the gas phase, so the efficiency of the combustion process is higher.
The self-ignition temperature of CNG is high, at 540oC.
The resulting pollution is lower.
CNG, which is derived from natural gas, is composed of methane gas (CH4) as the most abundant chemical compound. And here are the chemical compounds that make up CNG:
Hydrogen (H2) = 1.82%
Methane (CH4) = 93.33%
Ethylene (C2H4) = 0.25%
Carbon monoxide (CO) = 0.45%
Carbon dioxide (CO2) = 0.22%
Nitrogen (N2) = 3.40%
Oxygen (O2) = 0.35%
Hydrogen sulfide (H2S) = 0.18%
From the composition above, in the CNG combustion process the compounds CH4, C2H4, H2, CO, and H2S are burned. And the following is the combustion reaction of each of these compounds:
Methane Combustion Reaction
CH4 + 2O2 →CO2 + 2H2O + 37,705.49 kJ/m3
Ethylene Combustion Reaction
C2H4 + 3O2 →2CO2 + 2H2O + 59,948.74 kJ/m3
Hydrogen Combustion Reaction
H2 + 0.5 O2 →H2O + 12,079.17 kJ/m3
Carbon Monoxide Combustion Reaction
CO + 0.5 O2 →CO2 + 11,945.04 kJ/m3
H2S . Combustion Reaction
H2S + 1.5 O2 →SO2 + H2O + 23,957.14 kJ/m3
From the details above, the total calorific value (Qh) produced by burning 1 m3 is:
Qh = 35,190.53 + 149.87 + 219.84 + 53.75 + 43.12 = 35,657.11 kJ/m3