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??
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.
If you cannot find them, these can be estimated as the sum of the standard heats of formation of SO[sub]2[/sub], H[sub]2[/sub]O, CO[sub]2[/sub] 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):
Similarly for hydrogen sulfide and methyl mercaptan.
Then, multiply the heats of combustion by their vol%, and add the results. Kindly check my calculations.
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)
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)