Combustion Reaction for Natural Gas Containing Nitrogen & CO2

[Sirius P.Eng.]

So I am developing a first-principles model involving the combustion of a natural gas fuel source containing both nitrogen and CO2.

And even though this is quite basic, I have struggled with writing a balanced equation for the combustion of this fuel source with excess air, especially with the amount of O2 and N2 that will be in the flue gases.

I have attached an image of the equation. Please share any ideas you have to help me solve this one. The unknowns are x and y.

Ps: I am not a student.

 

[MartinLe]

1) are you sure that no N2 will combust?
2) x should be 1 + epsilon (A+B/4)-(A+1) if the rest is correct, I did not check
3) the most righthand part should read (1+ epsilon(A+B/4)*3.3762)N2. I think you confused yourself by writing x*3.762N2.

 

[davefitz]

N2 and co2 are sometimes added to natural gas to adjust the Wobbe Index , since most gas pipeline specifications/tariffs require that the supplied wobbe index be within a certain range. Appliances that are not automatically adjustable rely on an assumed wobbe index to assure that they will operate properly. The N2 and CO2 will also affect flame "flicker frequency" and flame speed, and this affects the rate of formation of pollutants N2O2 etc, so it affects the tuning of the combustors in large gas turbines which are required to limit their rate of pollutant discharge.

The use of raw unprocessed frack gas, and now proposals to use hydrogen ( from excess energy from renewables) , will affect the pipeline wobbe index, and it can be corrected by addition of N2 and co2, but it also implies the installed fleet of gas turbines will need to be upgraded to include automatic combustion tuning to ensure correct pollutant formation rates.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick