6 replies to this topic

[geo123]

CH4 is burned with an excess dry air to yield the following flue gas:

 

            % by volume

CO2     9.65

02        4.28

N2       86.07

 

Calculate the percent excess air supplied.

 

The answer is 18.55 %

What's the difference between an excess dry air and excess air?

Then, calculate the percent excess air supplied.

[geo123]

Need help.

[geo123]

URGENT I REALLY NEED HELP

[Ajay S. Satpute]

geo123,

 

Have you considered doing the calculations yourself first?

 

First step would be to write the CH4 oxidation equation and balancing it. Then you will realize that 1 mole of CH4 yields to 1 mole of CO2. Flue gases contain 9.65 mole (volume % = mole%), considering 100 mole flue gas basis. So CH4 has to be 9.65 moles.

 

1 mole of CH4 shall require 2 moles of O2, meaning O2 reacted is 9.65*2 = 19.3 moles. Flue gas has 4.28 moles of unreacted O2. So total O2 supplied = 19.3+4.28 = 23.58 moles.

 

Excess O2 supplied = 4.28 moles, so % excess O2 supplied = 4.28/23.58*100 = 18.2%.

 

 

 

Regards.

 

Ajay S. Satpute

[geo123]

I've done it. Thanks for the help anyway. Sorry I forgot to attach my working for the question.

Edited by geo123, 04 July 2015 - 09:39 AM.

[HABIB092]

CH4+2O2= CO2+2H2O

 

 

[HABIB092]

See the CH4  calc in attached  excel sheet.

Attached Files

•  CH4 CALC.xlsx   10.1KB   37 downloads