Scope
1.1 This test method covers the determination of the amount of carbon residue(Note1)left after evaporation and pyrolysis of an oil,and is intended to provide some indication of relative coke-forming propensities.
This test method is generally applicable to relatively nonvolatile petroleum products which partially decompose on distillation at atmospheric pressure.
Petroleumproductscontainingash-formingconstituentsas
determinedbyTestMethodD482orIPMethod4willhavean
erroneouslyhighcarbonresidue,dependingupontheamount
ofashformed(Note2andNote4).
NOTE 1—Theterm carbonresidue isusedthroughoutthistestmethod
todesignatethecarbonaceousresidueformedafterevaporationand
pyrolysisofapetroleumproduct.Theresidueisnotcomposedentirelyof
carbon,butisacokewhichcanbefurtherchangedbypyrolysis.Theterm
carbonresidue iscontinuedinthistestmethodonlyindeferencetoits
widecommonusage.
NOTE 2—Valuesobtainedbythistestmethodarenotnumericallythe
sameasthoseobtainedbyTestMethodD524.Approximatecorrelations
havebeenderived(seeFig.X1.1),butneednotapplytoallmaterials
whichcanbetestedbecausethecarbonresiduetestisappliedtoawide
varietyofpetroleumproducts.
NOTE 3—ThetestresultsareequivalenttoTestMethodD4530,(see
Fig.X1.2).
NOTE 4—Indieselfuel,thepresenceofalkylnitratessuchasamyl
nitrate,hexylnitrate,oroctylnitratecausesahigherresiduevaluethan