SovietRxiv

Study of the Individual Hydrocarbon Composition of Gasoline Fractions of Certain Western Siberian Crudes

S. I. Khoroshko, V. A. Kuznetsova, N. M. Smolyaninova
Submitted 1976 | SovietRxiv: ru-197601.12737 | Translated from Russian

Abstract Generated abstract

This study examines the individual hydrocarbon composition of gasoline fractions from crude oils of the Poludennoye, Luginetskoye, and Samotlor fields in Western Siberia. Fractions with boiling ranges up to 150°C, and up to 122°C for the Samotlor sample, were obtained by rectification and analyzed by capillary gas chromatography with flame ionization detection, using Kovats retention indices for identification and internal normalization for quantification. The analysis identified about 92 to 95 hydrocarbons in each gasoline, including normal and isoalkanes, cyclopentanes, cyclohexanes, and aromatics. The results indicate that paraffinic hydrocarbons predominate at more than half of the gasoline composition, naphthenic hydrocarbons average about 35%, and aromatic hydrocarbons occur in comparatively small amounts, with higher aromatic contents in the Poludennoye and Luginetskoye samples.

Full Text

STUDY OF THE INDIVIDUAL HYDROCARBON COMPOSITION OF GASOLINE FRACTIONS OF SOME CRUDE OILS FROM WESTERN SIBERIA

S. I. Khoroshko, V. A. Kuznetsova, N. M. Smolyaninova

(Presented by the scientific-methodological seminar of KhTG)

In the last 10–15 years, the problem of studying the physicochemical properties and material composition of crude oils and gas condensates, which constitute valuable raw material for petrochemistry, has acquired great national-economic and scientific importance. This has been promoted to a considerable degree by the rapid development of the chemistry of high-molecular compounds, as well as of the synthetic-materials industry, which requires millions of tons of organic raw material.

The aim of the present study was to investigate the individual hydrocarbon composition of gasolines (end point—150°C) from the oils of the Poludennoye, Luginetskoye, and Samotlorskoye fields. The work was carried out with fractions having end points of 60°C, 60–95°C, 95–122°C, and 122–150°C, obtained by rectification of the oil on a standard apparatus with 20 theoretical plates.

Gas-chromatographic analysis was performed on a “Khrom-2” chromatograph with a flame-ionization detector according to the procedure developed by R. I. Sidorov and M. P. Ivanova [1, 2, 3]. Copper capillaries 100–200 m long and with an internal diameter of 0.5 mm were used as columns. The stationary liquid phase (VM-4 vacuum oil), dissolved in benzene, was applied by forcing the solution through the capillary. Nitrogen served as the carrier gas.

The column of the instrument operated under isothermal conditions; each fraction was analyzed at several temperatures, which made it possible to decipher more fully the composition of the fractions under study. The analysis time for each fraction averaged 30–45 min.

Qualitative identification of the chromatograms was carried out using Kovats retention indices determined for the given temperatures. The chromatograms were calculated quantitatively by the method of internal normalization, taking correction coefficients into account. The average error was 5–8% relative.

The results of the study of the individual hydrocarbon composition of the gasolines are presented in Table 1.

Altogether, from 93 to 95 hydrocarbons were found in each broad gasoline fraction, including 5 unresolved pairs. The comparatively large percentage of the undeciphered portion is explained by the presence of hydrocarbons boiling above 150°C and occurring in the 122–150°C fraction owing to insufficient efficiency of the rectification apparatus.

The results of the study of the individual hydrocarbon composition of the gasolines show a high content of paraffinic hydrocarbons.

Table 1

Individual composition of gasolines (b.p.—150°)* from crude oils

No. Hydrocarbons Poludennoe, No. 221, 2236–2266 m: in gasoline Poludennoe, No. 221, 2236–2266 m: in crude oil Luginetskoe, No. 155, 2340–2354 m: in gasoline Luginetskoe, No. 155, 2340–2354 m: in crude oil Samotlor, No. 14, 1694–1701 m: in gasoline Samotlor, No. 14, 1694–1701 m: in crude oil
n-Paraffins
1. Ethane — — — — 0,09 0,013
2. Propane — — — — 2,97 0,437
3. Butane 0,04 0,08 0,55 0,140 8,84 1,300
4. Pentane 3,34 0,637 6,34 1,623 12,23 1,800
5. Hexane 6,21 1,185 7,90 2,028 10,33 1,520
6. Heptane 10,35 1,975 6,54 1,679 5,85 0,861
7. Octane 3,37 0,644 4,85 1,245 2,98 0,438
8. Nonane 3,33 0,635 2,23 0,571 — —
Total: 26,64 5,084 28,41 7,286 43,29 6,369
Isoparaffins
9. 2-Methylpropane — — — — 2,38 0,350
10. 2-Methylbutane 1,17 0,233 2,59 0,665 7,00 1,030
11. 2,2-Dimethylbutane 0,03 0,06 0,03 0,008 0,10 0,015
12. 2,3-Dimethylbutane 0,17 0,033 0,22 0,057 0,24 0,036
13. 2-Methylpentane 2,84 0,541 4,67 1,198 6,33 0,932
14. 3-Methylpentane 1,60 0,306 2,39 0,614 3,30 0,486
15. 2,2-Dimethylpentane 0,03 0,005 0,04 0,010 — —
16. 2,4-Dimethylpentane 0,29 0,055 0,33 0,084 0,55 0,081
17. 2,3-Dimethylpentane 0,85 0,162 0,58 0,150 0,56 0,082
18. 2,2,4-Trimethylpentane 0,06 0,011 0,03 0,007 0,03 0,005
19. 2,3,4-Trimethylpentane 3,24 0,618 0,16 0,042 0,13 0,019
20. 2-Methylhexane 3,24 0,618 1,87 0,481 1,09 0,160
21. 3-Methylhexane 4,79 0,914 2,48 0,638 3,18 0,498
22. 2,2-Dimethylhexane 0,06 0,011 0,03 0,008 — —
23. 3,3-Dimethylhexane 0,03 0,006 0,05 0,014 0,17 0,025
24. 2,5-Dimethylhexane 0,32 0,062 0,29 0,074 0,27 0,040
25. 2,4-Dimethylhexane 0,68 0,129 0,26 0,068 0,41 0,060
26. 2,3-Dimethylhexane + 2-Methyl-3-ethylpentane 0,21 0,041 0,26 0,066 0,20 0,030
27. 3,4-Dimethylhexane 0,17 0,032 0,13 0,034 — —
28. 2-Methylheptane 1,51 0,288 2,51 0,645 2,53 0,372
29. 3-Methylheptane 0,64 0,122 1,48 0,380 0,81 0,119
30. 4-Methylheptane 0,52 0,100 0,81 0,208 0,33 0,048
31. 2,4,4-Trimethylhexane 0,04 0,008 0,09 0,024 — —
32. 2,3,5-Trimethylhexane 0,02 0,004 0,15 0,038 — —
33. 2,2-Dimethylheptane 0,07 0,014 0,11 0,027 — —
34. 3,3-Dimethylheptane 0,05 0,009 0,05 0,014 0,07 0,010
35. 4,4-Dimethylheptane 0,12 0,023 0,03 0,008 — —
36. 2,4-Dimethylheptane 0,25 0,047 0,38 0,097 0,01 0,001
37. 2,5-Dimethylheptane 0,14 0,027 0,13 0,033 — —
38. 3,5-Dimethylheptane 0,11 0,021 0,11 0,029 — —
39. 2,6-Dimethylheptane 0,33 0,063 0,55 0,099 0,05 0,007
40. 2,3-Dimethylheptane 0,52 0,100 0,52 0,134 0,03 0,004
41. 3,4-Dimethylheptane 0,16 0,030 0,30 0,078 0,57 0,084
42. 2-Methyloctane 1,65 0,314 1,27 0,327 — —
43. 3-Methyloctane 1,67 0,319 1,29 0,330 — —
44. 4-Methyloctane 1,24 0,237 0,97 0,248 — —
45. 3-Ethylheptane 0,13 0,024 0,20 0,052 — —
Total: 25,82 4,926 27,36 6,989 30,54 4,494
Cyclopentanes
46. Cyclopentane [[unclear: value]] 0,095 0,77 0,198 1,96 0,288
47. Methylcyclopentane 4,90 0,935 5,44 1,394 5,89 0,866
48. 1,3-Dimethylcyclopentane, cis 1,73 0,330 0,86 0,220 0,99 0,146
49. 1,3-Dimethylcyclopentane, trans 1,47 0,281 0,66 0,170 1,06 0,156
50. 1,2-Dimethylcyclopentane, trans 3,08 0,589 1,79 0,461 2,23 0,328
1 2 3 4 5 6 7 8
51. 1,2-Dimethylcyclopentane, cis 0,51 0,097 0,61 0,156 0,18 0,026
52. 1,1,3-Trimethylcyclopentane 0,19 0,036 0,33 0,085
53. Ethylcyclopentane 1,61 0,308 1,34 0,344 1,23 0,181
54. 1,2,4-Trimethylcyclopentane, cis, trans, cis 0,60 0,114 0,62 0,159 0,24 0,036
55. 1,2,3-Trimethylcyclopentane, cis, trans, cis 0,62 0,119 0,70 0,179 0,53 0,078
56. 1,2,4-Trimethylcyclopentane, cis, cis, trans 0,09 0,017 0,08 0,021 0,31 0,046
57. 1,2,3-Trimethylcyclopentane, cis, cis, trans 0,07 0,013 0,07 0,017 0,27 0,040
58. 1,2,4-Trimethylcyclopentane, cis 0,12 0,022 0,15 0,039 0,14 0,021
59. 1,2,3-Trimethylcyclopentane, cis 0,19 0,036 0,26 0,066 0,37 0,055
60. 1-Methyl-2-ethylcyclopentane, trans + 1,1-dimethylcyclohexane 0,95 0,182 1,06 0,272 1,12 0,165
61. 1-Methyl-1-ethylcyclopentane 0,19 0,036 0,17 0,043 0,10 0,014
62. 1-Methyl-2-ethylcyclopentane, cis 0,38 0,073 0,37 0,095 0,01 0,002
63. Isopropylcyclopentane 0,13 0,024 0,17 0,044 0,07 0,010
64. n-Propylcyclopentane 0,51 0,098 0,63 0,162 0,05 0,007
65. 1,4-Dimethyl-2-ethylcyclopentane, cis, trans, cis + 1,4-dimethyl-2-ethylcyclopentane, cis, trans, trans 0,63 0,120 0,41 0,105 — —
Total: 18,47 3,524 16,49 4,230 15,07 3,679
Cyclohexanes
66. Cyclohexane 2,92 0,556 1,95 0,500 2,75 0,405
67. Methylcyclohexane 6,53 1,247 5,85 1,500 3,74 0,550
68. 1,4-Dimethylcyclohexane, trans 0,47 0,090 0,42 0,108 0,80 0,118
69. 1,3-Dimethylcyclohexane, cis 0,82 0,156 0,98 0,251 0,49 0,072
70. 1,2-Dimethylcyclohexane, trans 0,58 0,110 0,99 0,255 0,24 0,035
71. 1,3-Dimethylcyclohexane, trans + 1,4-dimethylcyclohexane, cis 0,31 0,059 0,39 0,101 0,04 0,006
72. 1,2-Dimethylcyclohexane, cis 0,24 0,046 0,25 0,064 0,01 0,002
73. Ethylcyclohexane 1,48 0,283 1,56 0,402 0,07 0,010
74. 1,1,4-Trimethylcyclohexane + 1,1,3-trimethylcyclohexane 1,13 0,216 0,95 0,243 — —
75. 1,3,5-Trimethylcyclohexane, cis 0,56 0,107 0,28 0,073 — —
76. 1,3,5-Trimethylcyclohexane, trans 0,30 0,057 0,21 0,055 — —
77. 1,2,4-Trimethylcyclohexane, cis, trans, trans 0,35 0,066 0,26 0,067 — —
78. 1,2,4-Trimethylcyclohexane, cis, trans, cis 0,41 0,078 0,20 0,052 — —
79. 1,2,4-Trimethylcyclohexane, cis, cis, trans + 1,2,4-trimethylcyclohexane, cis 0,60 0,114 0,44 0,113 — —
80. 1,2,3-Trimethylcyclohexane, cis, trans, cis 0,58 0,110 0,32 0,081 — —
81. 1,1,2-Trimethylcyclohexane 0,20 0,039 0,16 0,042 — —
1 2 3 4 5 6 7 8
82. 1-Methyl-3-ethylcyclohexane, cis 0,80 0,153 0,60 0,153 — —
83. 1-Methyl-4-ethylcyclohexane, trans 0,72 0,137 0,53 0,136 — —
84. 1-Methyl-3-ethylcyclohexane, trans 0,14 0,026 0,07 0,019 — —
85. 1-Methyl-2-ethylcyclohexane, trans 0,35 0,067 0,35 0,090 — —
86. 1,2,3-Trimethylcyclohexane, cis + 1-methyl-4-ethylcyclohexane, cis 0,26 0,050 0,33 0,085 — —
87. Isopropylcyclohexane 0,56 0,116 0,40 0,102 — —
88. n-Propylcyclohexane 0,30 0,057 0,45 0,116 — —
89. 1-Methyl-2-ethylcyclohexane, cis 0,08 0,015 0,09 0,023 — —
Total: 20,69 3,955 18,03 4,631 9,93 1,462
Aromatics
90. Benzene 0,20 0,038 0,62 0,159 0,17 0,025
91. Toluene 0,96 0,183 2,02 0,519 0,94 0,139
92. Ethylbenzene 0,76 0,145 1,01 0,260 0,06 0,008
93. p-Xylene 0,15 0,029 0,44 0,113 — —
94. m-Xylene 1,74 0,333 1,38 0,354 — —
95. o-Xylene 1,17 0,224 0,80 0,204 — —
96. Isopropylbenzene 0,32 0,062 0,49 0,125 — —
Total: 5,30 1,014 6,76 1,743 1,17 0,172
Not identified 3,08 0,587 2,95 0,757 — —
Grand total: 100,0 19,090 100,0 25,630 100,0 14,714

*) The individual composition of fractions of Samotlor crude oil was studied for gasoline with an end boiling point of 122°C.

In the fractions studied (more than 50% in the gasoline), normal and isoalkanes are present in approximately equal amounts. The isoparaffins are represented mainly by slightly branched structures containing one or two (rarely three) methyl groups. Isoalkanes with a quaternary carbon atom are present in insignificant amounts.

Among the cyclanes, hexamethylenes predominate in most cases; the total amount of naphthenic hydrocarbons in the gasolines averages 35%. Cyclopentane and cyclohexane hydrocarbons are represented by derivatives with methyl, ethyl, and propyl radicals, with monosubstituted cyclanes being found in the highest concentrations. As the length of the alkyl radical in the cyclic hydrocarbons increases, their content in the gasolines decreases.

Gasolines from Poludennaya and Luginetskaya crude oils are characterized by a fairly high content of aromatic hydrocarbons, among which m-xylene predominates. An elevated benzene content was noted in the gasoline from Luginetskaya crude oil.

Conclusions

  1. The individual hydrocarbon composition of gasoline fractions from the crude oils of the Poludennaya, Luginetskaya, and Samotlor fields has been studied.

  1. In each gasoline, 92–95 hydrocarbons belonging to different classes were found.

  2. In all the gasolines, paraffinic hydrocarbons predominate (more than 50% of the gasoline); the content of cyclanes averages 35%; aromatic hydrocarbons are present in small amounts.

REFERENCES

  1. R. I. Sidorov, M. P. Ivanova. Journal of Analytical Chemistry, 21, 4, 479, 1966.

  2. M. P. Ivanova, R. I. Sidorov, V. I. Petrova. In the collection: “Gas Chromatography.” NIITEKhIM, issue 8, 1968.

  3. R. I. Sidorov, M. P. Ivanova. Petrochemistry, 7, 4, 640, 1967.

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[v1] 1976

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Study of the Individual Hydrocarbon Composition of Gasoline Fractions of Certain Western Siberian Crudes