<VV> Catalytic Converter for Corvair

[bernievogler at comcast.net]

Thanks.  I stand corrected.  
Rotten egg is H2S not SO2. SO2 still smells "sulfury".  

H2S tends to confuse the body so that after some exposure the person is not as 
aware of how much they are smelling.   

SO2 won't form H2SO4 unless it is oxidized to SO3.  It is one of the stages of oxidation of the sulfur in fuel. The catalyst can surely accomplish that but so can some of the oxides of Nitrogen.  Since both are present in the exhaust stream at some point, the system will have H2S, S, SO2, and SO3. The exiting gases will be somewhat dependent upon transient temperatures.  Somewhere over 900°F the SO3 with breakdown to SO2.

Sounds like the exhaust process is pretty complex. Throw in the the hydrophilic properties of all of the oxides of sulfur and H2S and you have a whole different set of chemistry to review - H2SO3, H2SO4, etc.

Bernie


 -------------- Original message ----------------------
From: "John Kepler" <jekepler at amplex.net>
> 
> Craig is close on the rotten egg smell.  The smell is from Sulfur Dioxide
> (SO2) which could be a product of the thermal decay of sulfuric acid
> (H2SO4). 
> 
> No, it isn't!  The "rotten egg" smell is hydrogen sulfide, H2S which is
> formed by the catalysis of HC and residual sulfur in the exhaust.  H2S is
> whoppingly hydrophilic, and will readily form H2SO4 by hydrolysis 
> 
> 
> John
> 
>