Gas, Kerosene, Diesel Fuel Differences

   / Gas, Kerosene, Diesel Fuel Differences #1  

Anonymous Poster

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Now you wish you were a rocket scientist...

{from another web site}

Question

What is the difference between gasoline, kerosene, diesel fuel, etc.?

Answer



The "crude oil" pumped out of the ground is a black liquid called petroleum. This liquid contains aliphatic hydrocarbons, or hydrocarbons composed of nothing but hydrogen and carbon. The carbon atoms link together in chains of different lengths.
It turns out that hydrocarbon molecules of different lengths have different properties and behaviors. For example, a chain with just one carbon atom in it (CH4) is the lightest chain, known as methane. Methane is a gas so light, in fact, that it floats like helium. As the chains get longer they get heavier. The first 4 chains (CH4, C2H6, C3H8 and C4H10 or methane, ethane, propane and butane) are all gases that boil at -161, -88, -46 and -1 degrees F respectively. The chains up through C18H32 or so are all liquids and the chains above C19 are solids at room temperature.

The different chain lengths all have progressively higher boiling points, so they can all be separated by distillation. This is what happens in an oil refinery - crude oil is heated and the different chains are pulled out by their vaporization temperatures.

The chain lengths in the C5, C6 and C7 range are all very light, easily vaporized clear liquids called naphthas. They are used as solvents - dry cleaning fluids can be made from these liquids, as are paint solvents and other quick-drying products.

The chain lengths from C7H16 through C11H24 are blended together and used for gasoline. All of them vaporize at temperatures below the boiling point of water.

Next is kerosene in the C12 to C15 range, followed by diesel fuel and heavier fuel oils (like heating oil for houses).

Next come the lubricating oils. These oils no longer vaporize in any way at normal temperatures (for example, engine oil can run all day at 250 degrees F without vaporizing at all). Oils go from very light (like 3-in-1 oil) though various thicknesses of motor oil through very thick gear oils and then semi-solid greases. Vasoline falls in there as well.

Chains above the C20 range form solids, starting with paraffin wax, then tar and finally asphaltic bitumen used to make asphalt roads.

All of these different substances come from crude oil. The only difference is the length of the carbon chains!
 
   / Gas, Kerosene, Diesel Fuel Differences #2  
John -

Thanks very much for that post. /w3tcompact/icons/smile.gif

You very clearly explained something that has puzzled me for many years -- you even put it into terms that I can understand (no small feat).

What still remains unclear is the combustion properties of the liquid fuels you describe. I assume that the lower vapor point of the lighter ones makes them more "explosive", but does that also mean they burn hotter?

Just trying to tie this in with some other discussions (that you apparently have read) about adding gasoline to diesel and what effects that will have. Also, I'm not clear on why putting diesel in a gasoline engine burned it up.

I'm a kindergartener here, so please be gentle. /w3tcompact/icons/crazy.gif

HarvSig.gif
 
   / Gas, Kerosene, Diesel Fuel Differences
  • Thread Starter
#3  
Harv,

A rocket scientist, I'm not!

I found this info somewhere on the web and saved it because I was interested in it. I too, felt it was well written.

Upstate New York gets a little cold for diesels in the winter and I've been "cutting" my diesel fuel for years with kerosene.

I've also heard of some "crazy's" using "gasoline" to help start a cold diesel. I think those same people use gasoline to help start their "outdoor charcoal grills" and you read about them in the newspapers the next day...

Different fuel oil suppliers have stated the only difference between #2 and #1 fuel oil is #1 has "kerosene" mixed for anti-gel purposes. The same goes for "home heating oil" (#2 Fuel Oil) and "diesel fuel" (#2 Fuel Oil) difference being 1. the excise tax added at the pump (retail) 2. sometimes a "dye" is used with the retail version. So the bottom line is #2 Fuel oil is #2 Fuel oil, etc.

I was never a big fan of these "automotive additives" in the stores and the "claims of": fantastic increase in horsepower you'll get, teflon super lubrication for life, major increase in mpg... etc. Most of all are marketing gimmicks...
 
   / Gas, Kerosene, Diesel Fuel Differences #4  
Well John until you posted that last post you sure had me fooled. Whoever wrote that sure knew his or her stuff about oil. I was impressed to say the least.
Thanks for taking the time to post that.
Gordon
 
   / Gas, Kerosene, Diesel Fuel Differences #5  
John,

Two great posts. Thanks.

Bill Cook
 
   / Gas, Kerosene, Diesel Fuel Differences #7  
John,

Fractional distallation of petrolem as described worked just fine for a lot of years, but produces product quantities that don't fit the market demand. Cataltic Cracking modifys the compositon of the heavy hydrocarbons to more valuable lighter products like gasoline. Cracking is the major process of todays refineries.

http://instruct.uwo.ca/engin-sc/391b/Assignments/es512_420/fcc.html
 
   / Gas, Kerosene, Diesel Fuel Differences #8  
in the owners manual for a VW diesel pick-up; VW recommend mixing gas with the diesel during cold weather; i don't remember the ratio; i didn't believe it either till the VW owner brought he manual in; according to him, it made the starting a lot easier.
heehaw
 
   / Gas, Kerosene, Diesel Fuel Differences #9  
Harv, You may have it reversed. I don't think diesel in a gas engine will "Burn up" the engine, I don't think it will even ignite the diesel. Gas in a diesel though, I would think would have a tendency to "pre detonate", igniting as the piston was still coming up, instead of detonating at the top of the stroke and pushing the piston back down AFTER it had already maximized it's upwards travel. This is all just an educated guess - anyone out there with some facts instead of "theory"?? /w3tcompact/icons/smile.gif
 
   / Gas, Kerosene, Diesel Fuel Differences #10  
Ahh. Thanks, I needed that. The previous explanation left me scratching my head (do a lot of that these days /w3tcompact/icons/crazy.gif), because I have heard refinery-people talk about "cracking" all the time. So the previous explanation left me puzzled as to where "cracking" fit in. This explains a lot, and leaves one more little piece out of that great tome "Everything I don't know"....

The GlueGuy
 
 
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