Multi-dimensional high performance liquid chromatographic separation technique (STAR7) for quantitative determinations of 7 fractions in heavy petroleum streams boiling above 550 degrees F
View Patent ↗The present invention provides quantitation of seven classes of compounds (saturates, 1-4+ ring aromatics, sulfides, and polars) present in petroleum streams boiling from 550-1050° F. Operating the present invention in the preparative mode will allow us to load and collect multi-milligram amounts of material. In the present invention, all seven fractions are produced in a single run, whereas the most commonly used preparative liquid chromatographic separations requires two or more large scale separations to generate similar fractions. The present invention uses 100 times less solvent. The present invention protocol provides a quicker and cheaper alternative to most commonly used preparative liquid chromatographic separations and is flexible enough to target many refining and chemicals problems.
1. A method for the chromatographic analysis of hydrocarbon oil comprising:
Step 1: passing a mixture of the hydrocarbon oil and a first solvent sequentially through a 2,4-dinitro-anilinopropyl-silica gel (DNAP) and a silver ion strong cation ion exchange column (Ag + /SCX − ) to elute pure ‘saturate’ fraction of said oil and sending it to an evaporative light scattering detector (ELSD),
Step 2: passing a solvent through Ag + /SCX − to elute a fraction of said hydrocarbon oil, repeating steps 1 and 2 only with solvents chosen to elute different fractions of said hydrocarbon oil, back-flushing DNAP and Ag + /SCX − to elute different fractions, sending said eluting fractions to an evaporative light scattering detector (ELSD),
Step 3: detecting light scattered by said eluting fractions; and
Step 4: determining the composition of said hydrocarbon oil from said detected scattered light.
2. The method of claim 1 wherein said fractions include at least one of saturates, aromatic ring classes (1-14), sulfides and polars.
3. The method of claim 1 wherein said solvents include hexane, methylene chloride and toluene in various proportions, methylene chloride, toluene and iso-propanol in various proportions.
4. The method of claim 1 wherein said ELSD has a lower temperature of 550° F.
5. The method of claim 1 wherein said fraction includes saturates.
6. The method of claim 1 wherein said fraction includes aromatic ring classes.
7. The method of claim 1 wherein said fraction includes sulfides.
8. The method of claim 1 wherein said fraction includes polars.
9. A system for chromatographic analysis of hydrocarbon oil comprising
a solvent delivery system for supplying at least one of a plurality of solvents or mixtures thereof for use in connection with the chromatographic analysis of the hydrocarbon oil,
an auto-sampler, wherein the solvent delivery system being operatively connected to the auto-sampler,
a set of switching valves, wherein the auto-sampler being operatively connected to at least one switching valve of the set of switching valves,
a 2,4-dinitro-anilinopropyl-silica gel (DNAP) exchange column, wherein the DNAP exchange column being operatively connected to at least one switching valve of the set of switching valves
a silver ion strong cation ion exchange column (Ag + /SCX − ), wherein the cation ion exchange column being operatively connected to at least one switching valve of the set of switching valves, and
an evaporative light scattering detector (ELSD), wherein the ELSD being operatively connected to at least one switching valve of the set of switching valves.