Study of the Hydrocarbon Composition of Gasoline Fractions from Tomsk Crude Oil
Abstract Generated abstract
This study examines the hydrocarbon composition of straight-run gasoline fractions from Tomsk crude oil from well No. 18 of the Sosninsko-Sovetsko-Medvedevskoye field. Fractions obtained by distillation were analyzed for group composition by the aniline-point method after removal of aromatics on silica gel, and lighter fractions were further characterized by gas-liquid chromatography. The results show a predominance of paraffinic hydrocarbons in the combined initial boiling point to 200°C gasoline fraction, with aromatics increasing and naphthenes decreasing at higher boiling ranges, indicating low antiknock quality for direct motor gasoline use. At the same time, the high naphthene content and low sulfur levels of reforming-range fractions suggest that these straight-run gasolines are promising feedstocks for catalytic reforming.
Full Text
STUDY OF THE HYDROCARBON COMPOSITION OF GASOLINE FRACTIONS OF TOMSK OIL
N. M. Smolyaninova, K. K. Stramkovskaya, S. I. Smolyaninov,
N. M. Snegireva, L. F. Ponomareva, S. I. Khoroshko, L. F. Kotlova.
(Presented by the scientific-methodological seminar of the Faculty of Chemical Technology)
Gasoline fractions obtained by distillation of oil from well No. 18 of the Sosninsko-Sovetsko-Medvedevskoye field on an ARN-2 apparatus (GOST 11011-64) were investigated. The characteristics of the oil are given in [1].
Determination of the group composition was carried out by the aniline-point method, using KSM-grade silica gel to remove aromatic hydrocarbons [2]. The fractions were also characterized by specific gravity and refractive index. The results of the analyses are presented in Table 1.
The data show that in all light fractions of the oil studied, methane hydrocarbons predominate, the amount of which
Table 1
Group hydrocarbon composition of fractions from IBP to 200°C
| Temperature limits of fraction collection, °C | Yield on oil, wt. % | Density, $\rho_4^{20}$ | Refractive index | Content in the hydrocarbon fractions, % — aromatic | Content in the hydrocarbon fractions, % — naphthenic | Content in the hydrocarbon fractions, % — paraffinic |
|---|---|---|---|---|---|---|
| 28–60 | 3.6 | 0.6400 | 1.3700 | 0.0 | 0.0 | 100.0 |
| 60–95 | 5.6 | 0.7090 | 1.3928 | 0.8 | 38.7 | 60.5 |
| 95–122 | 4.9 | 0.7380 | 1.4090 | 3.5 | 33.8 | 62.7 |
| 122–150 | 6.0 | 0.7602 | 1.4245 | 10.2 | 31.4 | 58.4 |
| 150–200 | 10.4 | 0.7901 | 1.4420 | 20.6 | 19.8 | 59.6 |
| 28–200 | 30.5 | 0.7430 | 1.4125 | 10.0 | 25.0 | 65.0 |
decreases as the boiling temperature of the fraction rises. The content of naphthenes also decreases, while that of aromatics increases. The combined gasoline fraction (IBP—200°) contains 10% aromatics, 25% naphthenic and 65% paraffinic hydrocarbons. Such a hydrocarbon composition indicates a low antiknock quality
stability of the gasoline: its octane number (by analogy with gasoline from Romashkino crude oil of Tataria, which has almost the same composition [3]) is approximately 42 and, with the addition of TES in an amount of 0.822 g/kg, rises to 60. Consequently, only a component of lower-grade motor gasoline can be obtained from the oil of well No. 18.
However, the light fractions of this oil should undoubtedly be of interest as feedstock for catalytic reforming. It is known that the feedstock for this process consists of low-octane gasolines with boiling limits from 60 to 180°, obtained by direct distillation of oil. To obtain benzene, the 60–85° fraction is reformed; for toluene, 85–120°; for xylenes, 120–140°; and to obtain high-octane motor gasolines, the 85–180° fraction. The greater the amount of naphthenic hydrocarbons in the feed fraction, the higher the content of aromatics in the reformate gasoline, the better its quality, and the higher the yield [4].
Table 2 gives the characteristics of the fractions of the oil studied as feedstock for catalytic reforming; from it one can see that the content of naphthenic hydrocarbons in all fractions is very high and lies within the range from 33 to 44%, which is considerably higher than
Table 2
Characteristics of feedstock for catalytic reforming
| Temperature limits of fraction collection, °C | Yield on oil, wt. % | $\rho_{20}^{4}$ | Sulfur, % | Aromatic hydrocarbons, wt. % | Naphthenic hydrocarbons, wt. % | Methane hydrocarbons, wt. % |
|---|---|---|---|---|---|---|
| 62–85 | 3.6 | 0.7056 | absent | 0.8 | 43.7 | 55.5 |
| 62–105 | 7.3 | 0.7147 | " | 1.0 | 44.0 | 55.0 |
| 85–105 | 3.7 | 0.7280 | " | 1.5 | 44.3 | 54.2 |
| 85–120 | 6.2 | 0.7345 | traces | 2.3 | 39.7 | 58.0 |
| 85–180 | 18.9 | 0.7580 | " | 10.2 | 35.0 | 53.9 |
| 105–120 | 2.5 | 0.7413 | " | 3.5 | 32.8 | 63.7 |
| 105–140 | 6.8 | 0.7490 | " | 6.4 | 35.8 | 57.8 |
| 120–140 | 4.3 | 0.7554 | " | 7.7 | 37.4 | 54.9 |
| 140–180 | 8.4 | 0.7800 | 0.01 | 17.2 | 33.1 | 49.7 |
in the basic oils of the Volga–Ural region [5]. The low sulfur content of the feedstock is noteworthy, which is its major advantage.
The individual hydrocarbon composition of fractions up to 122°C was determined by gas-liquid chromatography on a KhL-4 chromatograph with a column length of 7.5 m and a diameter of 4.5 mm.
As the liquid phase, a mixture of Apiezon L and M was used, deposited on the inert support INZ-600 (fraction 0.25–0.5 mm). The analysis was carried out at a column temperature of 100°C, detector current of 110 mA, and carrier-gas (helium) flow rate of 120 ml/min.
The data are presented in Table 3.
The results obtained make it possible to conclude that the straight-run gasoline fractions of the oil from well No. 18 are of high quality as feedstock for catalytic reforming.
Table 3
Chromatographic separation of light oil fractions
| Name | Content of individual hydrocarbons in the fraction, % IBP—60°C |
Content of individual hydrocarbons in the fraction, % 60—95°C |
Content of individual hydrocarbons in the fraction, % 95—122°C |
Content of individual hydrocarbons of the IBP–122°C fraction, % of oil |
|---|---|---|---|---|
| isobutane | 1.57 | 0.02 | 0.06 | |
| n-butane | 7.93 | 0.07 | 0.28 | |
| isopentane | 14.59 | 0.15 | 0.53 | |
| n-pentane | 28.25 | 0.39 | 1.04 | |
| 2,3-dimethylbutane and 2-methylpentane | 13.45 | 2.72 | 0.63 | |
| 2,3-dimethylbutane | 0.25 | 0.01 | ||
| 3-methylbutane | 7.66 | 2.45 | 0.42 | |
| n-hexane | 17.35 | 13.55 | 1.39 | |
| 2,2-dimethylpentane | 0.29 | 0.93 | 0.06 | |
| methylcyclopentane and 2,4-dimethylpentane | 7.06 | 10.05 | 0.83 | |
| 3,3-dimethylpentane | 0.39 | 7.65 | 0.42 | 0.44 |
| 2-methylhexane and 3-methylhexane | 1.25 | 12.20 | 1.50 | 0.73 |
| cyclohexane | 8.70 | — | 0.49 | |
| n-heptane | 25.70 | 13.20 | 2.08 | |
| 1,2-dimethylcyclohexane (trans) | 0.65 | 1.10 | 0.10 | |
| 2,2-dimethylhexane | 0.54 | 1.43 | 0.10 | |
| 1,2-dimethylcyclopentane (cis) and 2,2-dimethylcyclopentane | 1.0 | 1.01 | 0.11 | |
| Methylcyclohexane | 9.55 | 13.80 | 1.24 | |
| 2,3-dimethylhexane | 1.66 | 18.11 | 1.00 | |
| 1,1,3-trimethylcyclopentane | 0.72 | 8.50 | 0.50 | |
| Toluene | 0.74 | 3.70 | 0.22 | |
| n-octane | 0.55 | 13.80 | 0.70 | |
| unidentified components | — | 23.43 | 1.14 | |
| Total: | 100.00 | 100.00 | 100.00 | 14.10 |
Conclusions
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The group composition of gasoline fractions of oil from well No. 18 of the Sosninsko-Sovetsko-Medvedevskoye field in Tomsk Oblast was studied.
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It was shown that the gasoline fractions of this oil are characterized by a low octane number.
References
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S. I. Smolyaninov, N. M. Smolyaninova, K. K. Stramkovskaya, S. I. Khoroshko. General study of oils from producing wells of the Sosninsko-Sovetsko-Medvedevskoye field. Izv. TPI, present volume.
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G. S. Landsberg, B. A. Kazanskii et al. Determination of the individual hydrocarbon composition of straight-run gasolines by a combined method. Publishing House of the Academy of Sciences of the USSR, Moscow, 1959.
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Petroleum Products. Properties, Quality, Application. Handbook, edited by B. V. Losikov. Khimiya, Moscow, 1966.
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I. R. Chernyi. Preparation of Feedstock for Petrochemistry. Khimiya, Moscow, 1966.
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S. N. Pavlova, Z. V. Driatskaya et al. Oils of the Eastern Regions of the USSR (reference book). Gostoptekhizdat, Moscow, 1962.