Quantification of asphaltene inhibitors in crude oil using thermal analysis coupled with mass spectrometry

Patent metadata

Field	Value
Publication number	US-9453830-B2
Application number	US-201414473287-A
Country	US
Kind code	B2
Filing date	Aug 29, 2014
Priority date	Aug 29, 2014
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

The present invention generally relates to a novel method for the characterization and quantification of involatile macromolecules in hydrocarbon samples of crude oil. More particularly, the method utilizes pyrolysis/gas chromatography/mass spectrometry (PY/GC/MS, PY/GC/MS/MS or PY/GC/triple quad MS) to detect and quantify polymeric asphaltene inhibitors in crude oil.

First claim

What is claimed is:

1. A method for determining the content of an asphaltene inhibitor in a hydrocarbon sample, the method comprising:
pyrolyzing a known amount of a hydrocarbon sample to form a degradation product of the asphaltene inhibitor;
separating the asphaltene inhibitor degradation product using a gas chromatographic method; and
detecting the asphaltene inhibitor degradation product with a mass spectrometer.

2. The method of claim 1 wherein the hydrocarbon sample is a crude oil.

3. The method of claim 2 wherein the asphaltene inhibitor is a polymer.

4. The method of claim 2 wherein the hydrocarbon sample is pyrolyzed at temperatures ranging from about 500° C. to about 800° C.

5. The method of claim 4 wherein the hydrocarbon sample is pyrolyzed at temperatures ranging from about 550° C. to about 700° C.

6. The method of claim 5 wherein the hydrocarbon sample is pyrolyzed at temperatures ranging from about 550° C. to about 600° C.

7. The method of claim 2 wherein the hydrocarbon sample is pyrolyzed for about 3 to about 10 seconds.

8. The method of claim 7 wherein the hydrocarbon sample is pyrolyzed for about 5 to about 7 seconds.

9. The method of claim 8 wherein the hydrocarbon sample is pyrolyzed for about 6 seconds.

10. The method of claim 2 wherein the hydrocarbon sample is heated at a temperature from about 80° C. to about 325° C. at a rate from about 20° C. to about 40° C. per minute.

11. The method of claim 10 wherein the hydrocarbon sample is heated at a temperature from about 80° C. to about 300° C. at a rate of about 30° C. per minute.

12. The method of claim 10 wherein the hydrocarbon sample is held at a temperature from about 300° C. to about 325° C. for about 30 seconds to 90 seconds.

13. The method of claim 12 wherein the hydrocarbon sample is held at a temperature at about 300° C. for about 60 seconds.

14. The method of claim 2 wherein the mass spectrometer detects a single mass/charge ratio value.

15. The method of claim 2 wherein the mass spectrometer detects a range of mass/charge ratio values.

16. The method of claim 2 wherein the asphaltene inhibitor is a polymer.

17. The method of claim 2 wherein the asphaltene inhibitor degradation products are ionized.

18. The method of claim 17 wherein the asphaltene inhibitor degradation products are quantitatively detected by mass spectrometry.

19. The method of claim 18 wherein the quantitative detection by mass spectrometry comprises comparing the peak area of a single mass/charge ratio associated with an asphaltene inhibitor fragment with a range of peak areas for the same single mass/charge ratio measured for an external calibration curve.

20. The method of claim 19 wherein the external calibration curve is determined by measuring the peak area of a single mass/charge ratio associated with the asphaltene inhibitor fragment for at least three samples containing a range of known concentrations of the asphaltene inhibitor in the hydrocarbon fluid and plotting the peak area of the single mass/charge ratio against the known concentration of the asphaltene inhibitor.

21. The method of claim 2 wherein the gas chromatographic method uses a polysiloxane capillary column.

Assignees

• Ecolab Usa Inc

Inventors

• Zhang Ying
• Casado-Rivera Emerilis

Classifications

• G01N30/72

  Mass spectrometers {(mass spectrometers per se H01J49/00)} · CPC title

• G01N30/7206

  interfaced to gas chromatograph (interfaces in general for introducing or extracting samples to be analysed with specially adapted mass spectrometer, see H01J49/04) · CPC title

• G01N33/28

  Oils {, i.e. hydrocarbon liquids} (edible oils or edible fats G01N33/03) · CPC title

• G01N33/2835 Primary

  Specific substances contained in the oils or fuels · CPC title

• G01N33/2823

  Raw oil, drilling fluid or polyphasic mixtures · CPC title