Heat of combustion CNCG

[lbvex]

Does anyone know how to calculate heat of combustion for CNCG gas mixtures ?

LB

 

[NeedAHoliday]

I though CNCG meant concentrated non condensable gas, as such we would need to know what you CNCG composition is to give a correct answer. Unless someone out there knows of a standard rough figure that is typical of some streams??

Cheers,

 

[lbvex]

The composition is:
(CH3)2S: 1 % , N2 : 67 % , H2O: 13 % , H2S : 15 %, CH3SH : 4 %. ( % by volume).

Regards

LB

 

[25362]

The combustibles are the sulfides: hydrogen, methyl and dimethyl. Use their heats of combustion per unit volume (or mol), multiply them by their vol% (ie, mol% as for an ideal gas mix), and add the results.

 

[lbvex]

Thank's "25632" for your reply.
But where can I find the heat of combustion for these sulfides ?

Regards

LB

 

[25362]

If you cannot find them, these can be estimated as the sum of the standard heats of formation of SO₂, H₂O, CO₂ resulting from stoichiometric combustion with oxygen plus the (negative) standard heat of formation of the chemical itself.

An example for dimethylsulfide considering water is condensed back as a liquid at 25 deg C and all other gases are returned to 25 deg C (standard state):

C₂H₆S + 4.5 O₂ => 2 CO₂ + 3 H₂O + SO₂​

The heat of combustion and standard heats of formation are given in kJ/mol.

carbon dioxide: 2[×]393.51 = 787.02
water: 6[×]142.915 = 857.49
sulfur dioxide: 1[×]296.8 = 296.80
dimethyl sulfide: -37.40

total heat of combustion, 1903.91

Similarly for hydrogen sulfide and methyl mercaptan.
Then, multiply the heats of combustion by their vol%, and add the results. Kindly check my calculations.

 

[lbvex]

"26352" ,

Thank you very much ! Yoy have helped me a lot.

Best regards

LB

 

[mbeychok]

LB:

I don't know where your CNCG will be combusted. If it is anywhere in the USA, I hope you realize the environmental permitting problems you will encounter for burning a gas that contains 15 volume percent H2S and 5 volume percent of organic sulfides.

Milton Beychok
(Contact me at www.air-dispersion.com)

 

[lbvex]

mbeychok,
This is a plant in Europe with a special combustion furnace.

LB

 

[mbeychok]

LB:

You should be aware that, in many European countries, there will be restrictions on the amount and/or concentration of SO2 which you will be permitted to emit to the atmosphere. You may have to provide a flue gas scrubber to remove SO2.

Milton Beychok
(Contact me at www.air-dispersion.com)