The effect of high sulfur fuel to 2 way catalyst
The effect of high sulfur fuel to 2 way catalyst
(OP)
Guys,
I need to get an answer to a technical problem that I am having. I know that high sulfur fuel is very detrimental to 3 way catalyst and lean burn aftertreatment. Will the high sulfur fuel be detrimental to 2 way catalyst which removes only CO and HC? Will the formation of sulphate acts negatively over the surface area?
I need to get an answer to a technical problem that I am having. I know that high sulfur fuel is very detrimental to 3 way catalyst and lean burn aftertreatment. Will the high sulfur fuel be detrimental to 2 way catalyst which removes only CO and HC? Will the formation of sulphate acts negatively over the surface area?





RE: The effect of high sulfur fuel to 2 way catalyst
RE: The effect of high sulfur fuel to 2 way catalyst
I don't know how much response you will get on this question beyond the above, because most of the specifics (e.g. activity reduction levels, recovery temperatures, and catalyst formulations) will be proprietary information.
RE: The effect of high sulfur fuel to 2 way catalyst
This makes me wonder on whether high sulfur fuel will react negatively to 2 way catalyst too.
RE: The effect of high sulfur fuel to 2 way catalyst
1) lean burn engines use diesel (typically) which is higher in sulfur relative to gasoline and natural gas in the unmodified state.
2) Lean engines require NOx control while stoichiometric engines largely require CO and unburned HC control. NOx control is more susceptible to sulfur poisoning than CO or unburned HC control.
RE: The effect of high sulfur fuel to 2 way catalyst
Bingo, I think you hit the spot with "NOx control is more susceptible to sulfur poisoning than CO or unburned HC control. ". I tend to agree very much with you especially when Lean NOx trap is used.
Few years ago, many of the latest GDI engine from German makers could not be introduced in China due to high sulfur fuel used. The normal port injection had no problem at all.
The next question that I have in mind, if the 2 way catalyst is affected by high sulfur fuel, how bad will it be?
RE: The effect of high sulfur fuel to 2 way catalyst
We didnt try to poison the cat with unrealistic levels of sulfur, just the extremes one might encounter with commercial grade propane. For what its worth, if unreasonable amounts of sulfur were introduced for long periods of time, I suspect a deterioration would result.
Franz
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RE: The effect of high sulfur fuel to 2 way catalyst
Keep in mind that "unrealistic levels" are relative. Diesel in the natural state can be 2000 ppm plus, which could be relevant for example if someone filled an on-road tank with off-road diesel. However, I think even off-road has standards below 250 ppm in many countries now, and certainly will have lower standards in the future. Engine oil can exceed 5000 ppm, and there are various conditions where at least some oil can get into the fuel, combustion chambers, and/or exhaust.
Also - the regeneration does reverse the sulfur damage as you indicate, it's the catalyst damage at high temperature that is the primary irreversible issue.
RE: The effect of high sulfur fuel to 2 way catalyst
RE: The effect of high sulfur fuel to 2 way catalyst
With or without the S, the oxidation catalysts degrade over time and have a relatively short (compared to the engine) useful life.