These are the heaviest and most complex molecules in crude oil, consisting primarily of carbon, hydrogen, nitrogen, oxygen, and sulfur. They are defined by their insolubility in light alkanes like pentane or heptane, but solubility in toluene. In refining, they are notorious for dropping out of solution and clogging pipes, heat exchangers, and catalysts.
Heard on the job
We've a severe pressure drop in the preheat train, probably asphaltane precipitation again.
Insider tip
Operators usually refer to these simply as asphaltenes. Monitoring their precipitation point is critical when mixing different crude slates.
Also heard as
- asphaltene