Table of Contents
- 1 Why is Wobbe Index important?
- 2 What is Wobbe Index for gas turbine?
- 3 What is the difference between calorific value and Wobbe Index?
- 4 How can I reduce my Wobbe Index?
- 5 What is the heating value of hydrogen?
- 6 What will be the effect of Wobbe index on Flam rate?
- 7 Which heating value is more important?
- 8 How is the Modified Wobbe Index calculated?
Why is Wobbe Index important?
It compares the energy output of different gases during combustion. The Wobbe index is essential for analyzing the impact of a fuel changeover and is also a common specification of appliances that use gas and of devices that transport gas.
What is Wobbe Index for gas turbine?
Most combustion turbine owners/operators and original equipment manufacturers (OEMs) measure gas composition and interchangeability using the “Wobbe Index.” The Wobbe Index defines the heating value of a quantity of gas that will flow though a hole (combustion turbine burner tip) of a given size in a given amount of …
What is the difference between calorific value and Wobbe Index?
The key difference between Wobbe index and Calorific Value is that the Wobbe index indicates the interchangeability of fuel gases whereas the Calorific Value indicates the total amount of heat energy generated when we burn a unit mass of fuel.
What is Wobbe Index correction?
An alternate format for the fuel gas composition correction is to express the performance changes as a function of the fuel Wobbe Index. Wobbe Index represents the energy density of the gas and is commonly used to gauge the extent to which a given gas is compatible with a given combustion system design.
What does higher heating value mean?
gross calorific value
The higher heating value (also known gross calorific value or gross energy) of a fuel is defined as the amount of heat released by a specified quantity (initially at 25°C) once it is combusted and the products have returned to a temperature of 25°C, which takes into account the latent heat of vaporization of water in …
How can I reduce my Wobbe Index?
To decrease the Wobbe Index of the natural gas, for example, a lower (or preferably zero) Wobbe Index component is added to create a blend. Options for this component include nitrogen (N 2) and carbon dioxide (CO 2). Alternatively, the Wobbe Index of the tail gas could have been increased.
What is the heating value of hydrogen?
120-142 MJ/kg
Heat Values of Various Fuels
| Heat value | |
|---|---|
| Hydrogen (H2) | 120-142 MJ/kg |
| Methane (CH4) | 50-55 MJ/kg |
| Methanol (CH3OH) | 22.7 MJ/kg |
| Dimethyl ether – DME (CH3OCH3) | 29 MJ/kg |
What will be the effect of Wobbe index on Flam rate?
Low Wobbe Index The can result in the following negative effects: Ignition problems – The equipment may not ignite if the energy content of the gas is too low. Flame instability and flashback – An unstable flame, and flashback through the fuel/air supply tube can occur. This may snuff the flame and damage equipment.
What happens when you burn propane?
Propane undergoes combustion reactions in a similar fashion to other alkanes. In the presence of excess oxygen, propane burns to form water and carbon dioxide. Complete combustion of propane produces about 50 MJ/kg of heat.
Why is heating value important?
Heating value is a very significant property of diesel fuels, because it gives the energy content of the fuel. The heating value is expressed as gross and net calorific value, depending on the status of water present in the exhaust. If water is present as liquid, then heating value is called gross calorific value.
Which heating value is more important?
The lower heating value (LHV) or higher heating value (HHV) of a gas is an important consideration when selecting a gas engine or CHP plant. Gas engines efficiency is typically quoted based upon the LHV of the gas. Whenever a hydrocarbon fuel is burned one product of combustion is water.
How is the Modified Wobbe Index calculated?
GE and others use the Modified Wobbe Index (MWI) as a measure of the interchangeability of gaseous fuels for a given system design. MWI=LHV [divided by] (SG x T[gas])[0.5], where T[gas] is the absolute temperature of the fuel gas in degrees Rankine.