Common Gaseous Fuels for Industrial Gas Fired Steam Boilers
Gaseous fuels have a high calorific value and are preferred option if it can be supplied continuously. The important properties of gaseous fuels are:-
- Chemical composition or Ultimate analysis of the fuel tells us the amount of carbon, sulfur, nitrogen, oxygen, moisture, and hydrogen present the fuel. The gas composition in dry-basis or moisture-free basis.
- Calorific value is the amount of energy released when 1 kg of fuel is burnt.
- Specific Gravity is a ratio of weight of fuel to the weight of air at the same volume.
Common Gaseous fuels are:-
Natural gas
Natural gas is considered an ideal fuel with negligible ash content and high heat value. Other advantages of the gas include:-
- It does not require storage facility.
- You do not require dust collector or ash disposal.
- Boiler control can be simple and sensitive.
- The boiler can be compact.
|
Constituents of Natural gas |
% Volume |
|
Methane |
91.7% |
|
Ethane |
4.13% |
|
Propane |
1.69% |
|
Butane |
0.52 |
|
Pentane |
0.3 |
|
Hexane |
0.21 |
|
Carbon dioxide |
0.33 |
|
Nitrogen |
1.03 |
|
GCV |
10490 kcal/kg |
Refinery gas
Refinery gas is by-product of distillation and crackling process in refineries. The gas is composed of paraffin and has low boiling point.
|
Constituents of Refinery Gas |
|
|
Co2 |
0.0-0.5% |
|
N2 |
0.0-10.0% |
|
H2 |
0.0-5% |
|
CH4 |
45-905 |
|
C2H6 |
2.0-30% |
|
C3H8 |
4.0-60% |
|
C4G19 |
0-50% |
|
GCV |
4,600-26,000 kcal/kg |
Coke Oven Gas
Coke Oven Gas is produced after destructive distillation of coal when coke is manufactured.
|
Constituents of Coke Oven Gas |
|
|
CO |
5-12% |
|
CO2 |
0.1-3.2% |
|
N2 |
2.4-12.12% |
|
O2 |
0.2-0.6% |
|
H2 |
27-57% |
|
CH4 |
28-50% |
|
C2H6 |
2.7-17% |
|
GCV |
9100-11700 kcal/kg |
Other popular gas are :-
- Blast furnace gas
- CO gas
Working of Gas fired boiler
Gas-fired boiler combusts gaseous fuels in excess air to produce the heat required for steam generation.
The key components in the gas-fired boiler are:-
- Burners
- Combustion chambers
- Heat Exchanger
- Control
The burner mixes the fuel with air together with the help of flame ignition. Burners in the most gas-fired boiler have a NOX setting to adjust the combustion process and the circulation of flue gas. Signals help to control the combustion. The burner settings are adjusted to ensure the highest NOx control at optimum performance and lowest unstable organic substance or carbon dioxide production. Controls regulate ignition, burner firing rate, fuel supply, air supply, exhaust draft, water temperature, steam temperature, and pressure.
The combustion of gas and air takes place in the combustion chamber. The various heat exchanger within the boilers helps to use the hot flue gas to convert water and steam.
Advantages of gas-fired boilers
- Natural gas is a clean fuel and does not produce harmful pollutants.
- Gas-fired boilers have higher thermal efficiency.
- Gas combustion does not generate soot and dust in the furnace during combustion extending the life of the boiler.
- Gas boilers require minimal or no pollution control equipment.
Mago Thermal provides engineering, procurement and installation of Industrial Gas Fired Steam Boilers. For more information, call us at +91-9910490700.