6 replies to this topic

[Fallenangelyk]

Hey I would like to know how the amount of air supply(insufficient, stoichiometric, and excess) to a heater affects the combustion heat energy of the fuel, e.g methane or ethane.

 

Thanks in advance for your help.

[Bobby Strain]

Not in the least.

 

Bobby

[breizh]

Hi ,

Consider the material attached .

Good luck

Breizh

[colt16]

Hey I would like to know how the amount of air supply(insufficient, stoichiometric, and excess) to a heater affects the combustion heat energy of the fuel, e.g methane or ethane.

 

Thanks in advance for your help.

 

The heating value of the fuel remains the same. However the amount of air affects the temperature of the flue gas and thus the temperature of the combustion side of the heater is lower. Therefore to get the same temperature in the process side, the amount of fuel required will be higher. 

You should optimize the excess air. Typically we measure the O2 at the flue gas and try to keep it 3-5mol%. If the figure is say, 7%, it means we are providing too much air than necessary for complete combustion and the heater will be consuming more fuel. 

[Fallenangelyk]

 

Hey I would like to know how the amount of air supply(insufficient, stoichiometric, and excess) to a heater affects the combustion heat energy of the fuel, e.g methane or ethane.

 

Thanks in advance for your help.

 

The heating value of the fuel remains the same. However the amount of air affects the temperature of the flue gas and thus the temperature of the combustion side of the heater is lower. Therefore to get the same temperature in the process side, the amount of fuel required will be higher. 

You should optimize the excess air. Typically we measure the O2 at the flue gas and try to keep it 3-5mol%. If the figure is say, 7%, it means we are providing too much air than necessary for complete combustion and the heater will be consuming more fuel. 

 

What is the 

 

 

Hey I would like to know how the amount of air supply(insufficient, stoichiometric, and excess) to a heater affects the combustion heat energy of the fuel, e.g methane or ethane.

 

Thanks in advance for your help.

 

The heating value of the fuel remains the same. However the amount of air affects the temperature of the flue gas and thus the temperature of the combustion side of the heater is lower. Therefore to get the same temperature in the process side, the amount of fuel required will be higher. 

You should optimize the excess air. Typically we measure the O2 at the flue gas and try to keep it 3-5mol%. If the figure is say, 7%, it means we are providing too much air than necessary for complete combustion and the heater will be consuming more fuel. 

 

When we provide too much oxygen, it will lower down the output temperature and lead to increase in fuel right? What will happen if we provide insufficient air for the combustion?

[colt16]

Hey I would like to know how the amount of air supply(insufficient, stoichiometric, and excess) to a heater affects the combustion heat energy of the fuel, e.g methane or ethane.
 
Thanks in advance for your help.

 
The heating value of the fuel remains the same. However the amount of air affects the temperature of the flue gas and thus the temperature of the combustion side of the heater is lower. Therefore to get the same temperature in the process side, the amount of fuel required will be higher. 
You should optimize the excess air. Typically we measure the O2 at the flue gas and try to keep it 3-5mol%. If the figure is say, 7%, it means we are providing too much air than necessary for complete combustion and the heater will be consuming more fuel.

What is the 
 

Hey I would like to know how the amount of air supply(insufficient, stoichiometric, and excess) to a heater affects the combustion heat energy of the fuel, e.g methane or ethane.
 
Thanks in advance for your help.

 
The heating value of the fuel remains the same. However the amount of air affects the temperature of the flue gas and thus the temperature of the combustion side of the heater is lower. Therefore to get the same temperature in the process side, the amount of fuel required will be higher. 
You should optimize the excess air. Typically we measure the O2 at the flue gas and try to keep it 3-5mol%. If the figure is say, 7%, it means we are providing too much air than necessary for complete combustion and the heater will be consuming more fuel.

When we provide too much oxygen, it will lower down the output temperature and lead to increase in fuel right? What will happen if we provide insufficient air for the combustion?

This should be a fairly obvious answer from high school chemistry. Combustion will run into the risk of being incomplete and instead of making CO2, you will start making CO and pollute the environment. Also your heat stack will start to see smoke.

[Saml]

Another issue is that you can go into a "Fuel Rich" condition. This is a dangerous condition that may lead to an explosion if operators do not respond adequately. Search in google "fuel rich condition in fired heaters" there are some good articles listed.