Hydrocarbon Composition of Oil Fractions from the Sobolinskoye Field
Abstract Generated abstract
This paper reports the group and structural hydrocarbon composition of gasoline, kerosene, gas oil, and higher boiling fractions from the Sobolinskoye oil field. Fractional distillation and established compositional methods are used to quantify paraffinic, naphthenic, aromatic, and structural group components across boiling ranges from the initial boiling point to above 400°C. The oil is characterized as paraffin naphthene type: gasoline fractions contain high paraffin levels and low aromatics, while aromatic content and average ring number increase markedly in heavier fractions. The study concludes that straight run gasoline fractions are unsuitable for commercial products because of expected low octane numbers, whereas low sulfur ligroin and kerosene gas oil fractions are considered favorable feedstocks for jet and diesel fuels.
Full Text
HYDROCARBON COMPOSITION OF OIL FRACTIONS FROM THE SOBOLINSKOYE FIELD
N. M. SMOLYANINOVA, M. E. SHLYKOVA, G. B. NEMIROVSKAYA
(Presented by the scientific-methodological seminar of the KhTF)
This paper presents data on the group hydrocarbon composition of gasoline (initial boiling point—200° C), kerosene (200—350° C), and oil (above 350° C) fractions of oil from the Sobolinskoye field, determined by methods indicated earlier.^1
The broad gasoline fraction (Table 1) is characterized by a high content of paraffinic hydrocarbons (61%), significant naphthenic hydrocarbons (28%), and low aromatic hydrocarbons (11%).
Table 1
Group hydrocarbon composition of oil fractions from the Sobolinskoye field from initial boiling point to 200° C
| Temperature limits for fraction collection, °C | Yield on oil, % | Refractive index, $n_D^{20}$ | Specific gravity, $d_4^{20}$ | Aromatic hydrocarbons, % | Naphthenic hydrocarbons, % | Paraffinic hydrocarbons, total, % | Paraffinic hydrocarbons, normal structure, % |
|---|---|---|---|---|---|---|---|
| 28—60 | 2.0 | 1.3810 | 0.6740 | 0 | 0 | 100 | 47 |
| 60—95 | 4.3 | 1.4019 | 0.7140 | 2 | 46 | 54 | 25 |
| 95—122 | 3.9 | 1.4123 | 0.7312 | 7 | 38 | 55 | 21 |
| 122—150 | 4.8 | 1.4261 | 0.7474 | 14 | 30 | 56 | 17 |
| 150—200 | 8.4 | 1.4409 | 0.7783 | 19 | 10 | 62 | 18 |
| 28—200 | 23.4 | 1.4229 | 0.7609 | 11 | 28 | 61 | 22 |
From the data in Table 1 it is evident that, with an increase in the temperature limits for collection of the gasoline fractions, the amount of aromatics in them increases, while the content of naphthenes decreases, especially noticeably upon transition to the ligroin cut (130—200° C). In the composition of the paraffinic hydrocarbons, representatives of isostructure predominate.
Upon transition to the kerosene–gas oil and oil cuts (Tables 2 and 3), the content of aromatic hydrocarbons increases significantly, from 22% in the 200—250° C fraction to 50% in the fraction above 400° C. The aromatic composition is characterized by the predominance in them of light representatives (benzene derivatives) with a refractive index ($n_D^{20}$) of less than 1.5300. With increasing boiling temperature, all
^1 N. M. Smolyaninova, G. B. Nemirovskaya, M. E. Shlykova. Hydrocarbon composition of gas condensates from fields of Tomsk Oblast. Present volume.
Table 2
Group hydrocarbon composition of fractions boiling above 200°C to the end point
| Fraction boiling range, °C | Yield on oil, % | Methane–naphthenic hydrocarbons, \(n_D^{20}\) | Methane–naphthenic hydrocarbons, % | 1st group of aromatic hydrocarbons, \(n_D^{20}\) | 1st group of aromatic hydrocarbons, % | 2nd group of aromatic hydrocarbons, \(n_D^{20}\) | 2nd group of aromatic hydrocarbons, % | 3rd group of aromatic hydrocarbons, \(n_D^{20}\) | 3rd group of aromatic hydrocarbons, % | 4th group of aromatic hydrocarbons, \(n_D^{20}\) | 4th group of aromatic hydrocarbons, % | Total aromatic hydrocarbons, % | Intermediate fractions, % |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 28–300 | 23.4 | — | — | — | — | — | — | — | — | — | — | 11 | — |
| 200–250 | 8.0 | 1.4348–1.4580 | 77 | 1.4822–1.5290 | 16 | 1.5321–1.5489 | 3 | 1.5602–1.5806 | 4 | — | — | 22 | 1 |
| 250–300 | 10.0 | 1.4430–1.4655 | 71 | 1.4741–1.5140 | 17 | 1.5340–1.5495 | 5 | 1.5569–1.5875 | 5 | — | — | 28 | 1 |
| 300–350 | 10.3 | 1.4510–1.4730 | 66 | 1.4985–1.5275 | 18 | 1.5506 | 4 | 1.5703–1.5894 | 4 | 1.6000–1.6232 | 5 | 32 | 2 |
| 350–400 | 12.7 | 1.4610–1.4809 | 56 | 1.4905–1.5040 | 23 | 1.5319–1.5412 | 4 | 1.5510–1.5900 | 7 | 1.5960–1.6207 | 8 | 42 | 2 |
| 400–432 | 7.0 | 1.4620–1.4803 | 48 | 1.4920–1.5159 | 29 | 1.5316–1.5444 | 7 | 1.5672–1.5893 | 4 | 1.5681–1.6250 | 10 | 50 | 2 |
Table 3
Group composition of oil fractions from the Sobolinskoye field
| Temperature limits for fraction collection, °C | Aromatic hydrocarbons, % | Naphthenic hydrocarbons, % | Paraffinic hydrocarbons, total, % | Paraffinic hydrocarbons, n-structure, % |
|---|---|---|---|---|
| 28—200 | 11 | 28 | 61 | 22 |
| 200—250 | 22 | 35 | 43 | 37 |
| 250—300 | 28 | 32 | 40 | 38 |
| 300—350 | 32 | 27 | 41 | 40 |
| 28—350 | 16 | 29 | 55 | 31 |
Table 4
Structural-group composition of fractions (by the \(n\)—\(d\)—\(M\) method) above 200°C
| Temperature limits for fraction collection, °C | \(n_D^{20}\) | Specific gravity \(d_4^{20}\) | Mol. wt. | Sulfur content, % | Carbon distribution, \(C_A\), % | Carbon distribution, \(C_H\), % | Carbon distribution, \(C_{\text{ring}}\), % | Carbon distribution, \(C_P\), % | Average number of rings per molecule, \(K_A\) | Average number of rings per molecule, \(K_H\) | Average number of rings per molecule, \(K_O\) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 200—250 | 1.4600 | 0.8245 | 181 | 0.12 | 14 | 25 | 39 | 61 | 0.29 | 0.72 | 1.01 |
| 250—300 | 1.4735 | 0.8450 | 218 | 0.21 | 17 | 24 | 43 | 57 | 0.46 | 0.71 | 1.17 |
| 300—350 | 1.4850 | 0.8670 | 261 | 0.33 | 18 | 24 | 42 | 58 | 0.45 | 0.89 | 1.34 |
| 350—400 | 1.5040 | 0.8945 | 317 | 0.47 | 24 | 15 | 39 | 61 | 0.94 | 0.80 | 1.74 |
| 400—432 | 1.5135 | 0.9147 | 358 | 0.58 | 23 | 17 | 40 | 60 | 1.03 | 1.18 | 2.21 |
Polycyclic representatives begin to play a major role in the composition of the aromatic portion. This is also indicated by the data on structural-group composition presented in Table 4. It can be seen that the average number of rings in the molecule (\(K_A\)) increases sharply from 0.29 in the 200—250°C fraction to 1.03 in the highest-boiling cut. The share of carbon attributable to aromatic structures (\(C_A, \%\)) also increases with increasing boiling temperature of the fractions.
For the kerosene-gasoil cuts (Table 4), a predominant content of paraffinic hydrocarbons of normal structure is characteristic.
Thus, according to the data on group hydrocarbon composition, the oil from the Sobolinskoye field belongs to the paraffin-naphthene type.
Owing to the high content of hydrocarbons of the methane series, the gasoline cuts will apparently have low octane numbers. The low sulfur content and the large amount of methane-naphthenic hydrocarbons in the ligroin and kerosene-gasoil fractions provide grounds for assessing them as favorable feedstock for the production of jet and diesel fuels.
Conclusions
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The hydrocarbon composition of fractions of Sobolinskaya oil has been determined.
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It has been established that this oil belongs to the paraffin-naphthene type.
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It has been shown that gasoline fractions from the straight-run distillation of Sobolinskaya oil cannot be used to obtain commercial products. Ligroin and kerosene-gasoil cuts may serve as favorable feedstock for the production of jet and diesel fuels.