Oil question re paraffinic oil in a recent post


#1

In another place I was trying to answer a question and found this.

“Fact: There are two basic types of crude oil, naphthenic and paraffinic. Most conventional engine lubricating oils today are made from paraffinic crude oil. Paraffinic crude oil is recognized for its ability to resist thinning and thickening with temperature, as well as its lubricating properties and resistance to oxidation (sludge forming tendencies). In the refining process, the paraffinic crude oil is broken down into many different products. One of the products is wax, and others are gasoline, kerosene, lubricating oils, asphalt, etc. Virtually every oil marketer uses paraffinic base stocks in blending its engine oil products. Many people believe the term paraffinic to be synonymous with wax. Some have the misconception that paraffinic oils will coat the engine with a wax film that can result in engine deposits. This is not true. The confusion exists because paraffinic molecules can form wax crystals at low temperatures. In lubricating oils, this wax is removed in a refining process called dewaxing. Wax is a premium product obtained from crude oil, and in order to ensure that we produce the highest quality base stocks available, Havoline removes the maximum amount of wax possible during the refining process. The end result is a motor oil product formulated with premium lubricating base oil.”

Any comments?


#2

http://www.texlube.com/oilmyths.htm


#3

I always direct my oil questions to:


#4

Paraffin materials are a straight chain hydrocarbon with a specific ratio of carbon to hydrogen. Heavier weight paraffins can be waxes. But methane is also a paraffin.


#5

Wiki has a good explanation of the differences:

“Naphthenic oil is a type of mineral oil. In contrast with paraffinic oils, naphthenic oils contain only low to no proportion of n-alkanes, being based on cycloalkanes (naphthenes) instead. The low-temperature behavior of naphthenic oils is better than of paraffinic oils, making them suitable for applications that require low pour point. The degradation products of naphthenic oils are soluble in the oils, leading to fewer problems with formations of sludges and deposits. Naphthenic oils have different solvent properties than paraffinic oils. Naphthenic oils are characterized by high proportion of cyclic hydrocarbon fraction. The convention is that when the paraffinic carbon content is less than 55-60%, the oil is labeled as naphthenic”

And a clarification: OP said “the refining process, the paraffinic crude oil is broken down into many different products. One of the products is wax, and others are gasoline, kerosene, lubricating oils, asphalt, etc.”

That’s close, but it’s better to say “the paraffinic crude oil is separated…”, rather than “broken down”. While some ‘breaking’ of long-chain molecules occurs, the main way a refinery creates all those different products is through separation using heat (distillation).


#6

The issue is settled for me. I had better not find that Quaker State has been buying the leftover wax. All the science fact in the world could be wasted if just one motor oil maker got caught doing just what urban legend said they were doing.

I just want to create one legend in my own mind that catches fire in the minds of my fellow non-scientists. I may have to settle for misusing old sayings.