Any Petrol Chemist on here?

[pgfpro]

I would like to know what the octane of NAPHTHA, LIGHT ALIPHATIC is?

Also the octane rating of HEAVY AROMATIC NAPHTHA?

Thanks in advance.

[rmay635703]

Planning on burning moth balls?

[pgfpro]

Originally Posted by rmay635703

Planning on burning moth balls?

Nope lol I can get another 50 gallons reducer for free. Just trying to make a low boost race fuel.

[Lemmy]

Very, very low. Something like 70 or less. Wouldn't make a very racy fuel.

[pgfpro]

Originally Posted by Lemmy

Very, very low. Something like 70 or less. Wouldn't make a very racy fuel.

Kind of what I thought. I have been running it straight in my car on very low boost and the knock sensor gave me a few counts when I started turning it up. I did have some that it was manageable but that was only 50% with my waste solvent blend.

[RustyLugNut]

Octane ratings below about 60 fall into the region of diesel fuel. At that point they are tested for cetane rating. The opposite of octane rating. Naptha works great as a diesel additive and is often used as such.

[rmay635703]

Blend it with a little pure ethanol

[joemac]

U.S. pumps report octane as AKI, which is (RON+MON)/2. Light naphtha has an AKI of 71, while heavy has AKI of 62. RON and MON are close for both naphthas (i.e., low sensitivity). For diesels, I found a cetane number for light naphtha, but not heavy. Light naphtha cetane is about 34. So, in a spark ignition engine, compression ratio would have to be fairly low (less than 8:1) and you would need additional spark retard to run on naphtha. Sufficiently vaporizing heavy naphtha without some sort of fuel preheat would be a real challenge for most modern fuel injection systems. For diesels, just the opposite issues. You would need a higher compression ratio and white smoke on cold start would be an issue due to the long ignition delay times

As a blend for use in modern spark ignition gasoline engines, you would need more than a little pure ethanol to get to a reasonable AKI rating. Ethanol has an RON/MON/AKI of 108.6/89.7/99.15. You would need to blend about 60% ethanol with light naphtha to get something close to 87 AKI regular grade and about 70% ethanol with heavy naphtha to get something similar there. Also, I'm not sure heavy naphtha will vaporize enough to sufficiently mix with the air charge without preheating. Light naphtha is often one of the compounds used as part of the petroleum components of E85.

Naphthas are a major component of "producer gas", which used to be used to fuel tractors. They typically ran water-jacket fuel preheaters, ~6:1 compression ratio, and had a separate fuel tank for gasoline to allow for startup and warmup on gasoline before switching over to producer gas.

[RustyLugNut]

You might want to try running the naphtha in a lean burn mode to see if it can effectively combust without knocking since lean burn combustion slows down as the air/fuel ratio increases.

[pgfpro]

Originally Posted by RustyLugNut

You might want to try running the naphtha in a lean burn mode to see if it can effectively combust without knocking since lean burn combustion slows down as the air/fuel ratio increases.

I did do some testing with it this winter. My engine seems to be OK with it in lean burn and light load, but at mid load it will knock. So now I'm using it to heat a garage this winter. lol