'.....

Engine Power = 1980 bhp

BSFC = 7792 Btu/bhp-hr

Total exhaust heat = 4527 Btu/hr

....'

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Are you certain these are correct/close?

The second was certainly wrong, it should be in gram/ kwh or equivalent. The third one means the engine output power is only A few watt! Not 1980 bhp.

Correction, the engine power is only about 1 kw at best.

the third one: Total exhaust heat Btu/Hr = 4527x1000 = 4527000 Btu/hr

BSFC is 7792 Btu/Bhp-hr or 11027 KJ/KWh

Your local diesel repair shop might have a portable engine exhaust gas analyzer, I would start there...

Do you want to buy a converter for your engine or do you have to buy one?

Wanting one for an engine that large is going to be a very expensive and for the most part waste of time effort and money.

However if you have to buy one to meet some political emissions specs what the fine cost Vs what the converter going to cost?

Just trying to save you some money and efforts here.

I have to buy one.

Client requirements -.-

Not much I can do about that!

Now that's more like it!

Oooops! '10N₂' should read '8N₂', though it doesn't affect the outcome.

_{Got in very late last night.}

Yea, I was just going to say that.

Great information. I am amazed at the knowledge that shows up here.

'....CH₄ + 2O₂ + roughly 10 N₂(inert) → CO₂ + 2H₂O↑ + roughly 10N₂(inert), so there is no increase in the number of molecules as a result of combustion. Therefore the mole fraction of sulphur compounds in the exhaust is not diminished by any increase in molecules of the main fuel's combustion.

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Therefore the maximum SO₂ in the exhaust will be simply 800ppm x 64/34.

....'

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There is a problem with the above. While it is unclear whether the ppm H₂S, provided by the OP, is based on volume, mass, or molarity (which does affect the outcome), the above calculation significantly overestimates probable exhaust SO₂ concentrations.

Consider for a moment the following hypothetical...

62 grams of a mixture of steam (H₂O) and CO2 ( in a 1 to 1 molar ratio) that also contains ~1506 ppm SO₂ (assume ppm mass or ppm mole) at 15 psia and 250 F.,

is added to

280 grams of N₂ at 15 psia and 250 F.

As expected there is no evidence of any significant reaction.

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Will the SO₂ concentration remain close to ~1506 ppm?

.

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Hopefully you agree that the concentration SO₂ will be much lower than 1506 ppm (800 * 64/32 ppm) regardless of whether you chose ppm mole or mass. even though no reaction occurred the SO₂ concentration was diluted with the addition to N₂.

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The concentrations in this hypothetical are not much different from what the stoichiometric reaction you suggested above should yield. The concentrations should not remain static from the fuel to the exhaust.

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I should note that you do qualify your statement with '...the maximum SO₂ in the exhaust will be... ' which is technically true, since the actual concentrations will be around an order of magnitude lower. If this was your intention, then I simply misjudged what you were attempting to communicate. if not then I'm just noting a forgotten component of the otherwise helpful calculation you provided.