Study of Gas Condensate from the Kazan Field
Abstract Generated abstract
The paper reports a compositional study of gas condensate from the Kazan gas condensate field in Tomsk Oblast, focusing on its physicochemical properties and gasoline-range hydrocarbon fractions. Group composition of fractions boiling up to 200°C was determined by the aniline-point method after removal of aromatics on silica gel, and the individual composition of the initial boiling point to 122°C fraction was analyzed by gas-liquid chromatography. The condensate was found to have low density, low molecular weight, very low sulfur content, and no resinous or asphaltene substances, with paraffinic hydrocarbons predominating and appreciable naphthenic content. The results characterize the condensate as methane-naphthenic and indicate that its gasoline distillates are suitable as feedstock for pyrolysis to gaseous monoolefins and for catalytic reforming.
Full Text
STUDY OF GAS CONDENSATE FROM THE KAZAN FIELD
S. I. SMOLYANINOV, V. A. KUZNETSOVA, N. M. SMOLYANINOVA
(Presented by the scientific-methodological seminar of KhTF)
The Kazan gas-condensate field is located in the Parabel District of Tomsk Oblast. Gas-bearing strata have been identified within the Tyumen and Vasyugan formations. All gas-bearing horizons are commercially productive. The condensate factor averages 771.5 cm³/m³ in terms of stable condensate.
This paper presents the results of a study of the physicochemical properties and hydrocarbon composition of the Kazan gas condensate.
The group hydrocarbon composition of fractions boiling up to 200°C was determined by the aniline-point method, with the aromatics removed by adsorption on silica gel.
The individual hydrocarbon composition of the broad fraction from initial boiling point to 122°C was determined by gas–liquid chromatography according to the method of M. I. Ivanova [1].
The physicochemical characteristics of the condensate under study are given in Table 1. The condensate is characterized by low density (0.7274) and low molecular weight (111). Resinous and asphaltene substances are absent; the sulfur content is 0.05%.
Data on the determination of the group hydrocarbon composition (Table 2) show that paraffinic hydrocarbons predominate in the gasoline fractions of the condensate, with a significant content among them of normal-structure alkanes.
The amount of naphthenes is 18–33% and decreases with increasing boiling temperature of the distillate; the aromatics content increases from 1 to 10%.
The individual hydrocarbon composition of the fraction from initial boiling point to 122°C is given in Table 3. It is interesting to note that among the cyclanes the content of five-membered hydrocarbons is twice as high as that of six-membered hydrocarbons.
Iso-structure methane hydrocarbons are represented mainly by monosubstituted compounds.
The content of cyclohexane and methylcyclohexane in the fraction is 3.29% and 4.81%, respectively.
On the basis of the hydrocarbon composition of the gasoline distillates of the condensate, it may be concluded that they meet all the requirements imposed on feedstock for pyrolysis for the purpose of obtaining gaseous monoolefins: the light fractions consist mainly of methane hydrocarbons, the aromatics content is low, and the feedstock is practically sulfur-free.
Table 1
Physicochemical characteristics of the Kazan sample of condensate
| No. | Indicator name | Indicator value |
|---|---|---|
| 1. | Density, \(d^{20}_{4}\) | 0.7274 |
| 2. | Molecular weight | 111 |
| 3. | Kinematic viscosity at 20°C, cSt | 0.81 |
| 4. | Pour point, °C | −54 |
| 5. | Paraffin content, % | traces |
| 6. | Acid number, mg KOH per 100 ml of condensate | 0.021 |
| 7. | Naphthenic acid content, % | 0.006 |
| 8. | Phenol content, % | 0.002 |
| 9. | Fractional composition according to GOST 2177-59: initial boiling point, °C | 49 |
| 9. | Fractional composition according to GOST 2177-59: distillation up to 100°C, % | 29.0 |
| 9. | Fractional composition according to GOST 2177-59: » up to 150°C, % | 60.5 |
| 9. | Fractional composition according to GOST 2177-59: » up to 200°C, % | 77.0 |
| 9. | Fractional composition according to GOST 2177-59: final boiling point, °C | 92.5 |
| Elemental composition, %: C | 85.10 | |
| Elemental composition, %: H | 14.73 | |
| Elemental composition, %: N | 0.01 | |
| Elemental composition, %: S | 0.05 | |
| Elemental composition, %: O | 0.11 |
Table 2
Group hydrocarbon composition of gasoline fractions of Kazan gas condensate
| Temperature limits of fraction collection, °C | Yield on condensate, % | Refractive index, \(n^{20}_{D}\) | Aromatics | Naphthenes | Methanes, total | Methanes, normal structure |
|---|---|---|---|---|---|---|
| i.b.p.–60 | 11.94 | 1.3625 | 0 | 0 | 100 | 62 |
| 60–95 | 23.04 | 1.3922 | 1 | 31 | 68 | 32 |
| 95–122 | 15.43 | 1.4069 | 2 | 33 | 65 | 27 |
| 122–150 | 13.26 | 1.4170 | 6 | 24 | 70 | 26 |
| 150–200 | 14.99 | 1.4308 | 10 | 18 | 72 | 24 |
| i.b.p.–200 | 78.68 | 1.4017 | 4 | 23 | 73 | 33 |
Table 3
Individual hydrocarbon composition of the stabilized gasoline fraction i.b.p.–122°C of Kazan gas condensate
| No. | Components | Hydrocarbon content, wt. %, in the fraction | Hydrocarbon content, wt. %, in the condensate |
|---|---|---|---|
| 1. | Isobutane | 0.11 | 0.054 |
| 2. | n-Butane | 7.17 | 3.609 |
| 3. | Isopentane | 6.05 | 3.061 |
| 4. | n-Pentane | 7.54 | 3.800 |
| 5. | 2,2-Dimethylbutane | 0.41 | 0.209 |
| 6. | 2,3-Dimethylbutane | 0.21 | 0.105 |
| 7. | 2-Methylpentane | 1.74 | 0.887 |
| 8. | Cyclopentane | 5.01 | 2.516 |
| 9. | 3-Methylpentane | 3.77 | 1.907 |
| 10. | n-Hexane | 10.73 | 5.480 |
| 11. | 2,2-Dimethylpentane | 0.01 | 0.002 |
| 12. | 2,4-Dimethylpentane | 0.41 | 0.210 |
| 13. | Methylcyclopentane | 6.08 | 3.063 |
| 1 | 2 | 3 | 4 |
|---|---|---|---|
| 14. | Benzene | 0,12 | 0,060 |
| 15. | 2-Methylhexane | 3,61 | 1,840 |
| 16. | Cyclohexane | 3,38 | 1,721 |
| 17. | 3-Methylhexane | 3,29 | 1,697 |
| 18. | 2,3-Dimethylpentane | 1,04 | 0,526 |
| 19. | 1,3-Dimethylcyclopentane (cis) | 1,43 | 0,726 |
| 20. | 1,3-Dimethylcyclopentane (trans) | 2,22 | 1,150 |
| 21. | n-Heptane | 8,65 | 4,400 |
| 22. | 2,2-Dimethylhexane | 0,42 | 0,213 |
| 23. | 2,4-Dimethylhexane | 0,72 | 0,361 |
| 24. | Methylcyclohexane | 4,81 | 2,409 |
| 25. | 1,1,3-Trimethylcyclopentane + 1,2-dimethylcyclopentane (cis) | 0,62 | 0,315 |
| 26. | Ethylcyclopentane | 0,96 | 0,485 |
| 27. | 3,3-Dimethylhexane | 0,64 | 0,322 |
| 28. | 1,2,4-Trimethylpentane (cis, trans, cis) | 0,39 | 0,197 |
| 29. | 1,2,3-Trimethylcyclopentane (cis, trans, cis) | 1,03 | 0,516 |
| 30. | 2,3-Dimethylhexane | 0,25 | 0,127 |
| 31. | 2-Methyl-3-ethylpentane | 0,45 | 0,225 |
| 32. | 2,3,4-Trimethylpentane | 0,13 | 0,065 |
| 33. | 1,1,2-Trimethylcyclopentane | 0,13 | 0,064 |
| 34. | 2-Methylheptane | 2,74 | 1,385 |
| 35. | 3-Methylheptane | 1,67 | 0,842 |
| 36. | 3,4-Dimethylhexane | 0,55 | 0,280 |
| 37. | Toluene | 0,80 | 0,405 |
| 38. | 4-Methylheptane | 0,19 | 0,598 |
| 39. | 1,2,4-Trimethylcyclopentane (cis, cis, cis) | 0,17 | 0,088 |
| 40. | 1,2,4-Trimethylcyclopentane (cis, cis, trans) | 0,10 | 0,048 |
| 41. | 1,2,3-Trimethylcyclopentane (cis, cis, trans) | 0,08 | 0,040 |
| 42. | 1,4-Dimethylcyclohexane (trans) | 1,42 | 0,736 |
| 43. | 1,3-Dimethylcyclohexane (cis) | 0,02 | 0,012 |
| 44. | 1-Methyl-3-ethylcyclopentane (cis) + 1-methyl-2-ethylcyclopentane (trans) | 1,23 | 0,619 |
| 45. | n-Octane | 3,17 | 1,607 |
| 46. | 1-Methyl-1-ethylcyclopentane | 0,12 | 0,060 |
| 47. | 1,2,3-Trimethylcyclopentane (cis, cis, cis) | 0,76 | 0,384 |
| 48. | 1,2-Dimethylcyclopentane (trans) | 0,05 | 0,025 |
| 49. | 2,4,4-Trimethylhexane | 0,06 | 0,028 |
| 50. | 1,4-Dimethylcyclohexane (cis) + 1,3-dimethylcyclohexane (trans) | 0,04 | 0,020 |
| 51. | 2,2-Dimethylheptane | 0,06 | 0,030 |
| 52. | Isopropylcyclopentane | 0,09 | 0,044 |
| 53. | 2,4-Dimethylheptane | 0,10 | 0,050 |
| 54. | 1-Methyl-2-ethylcyclopentane | 0,05 | 0,027 |
| 55. | 2,6-Dimethylheptane | 0,36 | 0,029 |
| 56. | 2,5-Dimethylheptane + 3,5-dimethylheptane | 0,04 | 0,019 |
| 57. | 1,2-Dimethylcyclohexane (cis) | 0,06 | 0,029 |
| 58. | n-Propylcyclopentane | 0,09 | 0,047 |
| 59. | Ethylcyclohexane | 0,50 | 0,257 |
| 60. | 3,3-Dimethylheptane | 0,08 | 0,041 |
| 61. | 1,1,3-Trimethylcyclohexane + 1,1,4-trimethylcyclohexane | 0,21 | 0,107 |
| 62. | 3,3,4-Trimethylhexane | 0,05 | 0,028 |
| 63. | 1,4-Dimethyl-2-ethylcyclopentane (cis, trans, cis) + 1,4-dimethyl-2-ethylcyclopentane (cis, trans, trans) | 0,04 | 0,021 |
| 64. | 1,3,5-Trimethylcyclohexane (cis) | 0,05 | 0,024 |
| 65. | Ethylbenzene | 0,09 | 0,045 |
| 66. | 3-Methyl-3-ethylhexane + 2,3-dimethylheptane | 0,08 | 0,042 |
| 67. | 3,4-Dimethylheptane | 0,03 | 0,016 |
| 68. | 1,3,5-Trimethylcyclohexane (trans) + 1,2,4-trimethylcyclohexane (cis, trans, trans) | 0,05 | 0,022 |
| 69. | 2-Methyloctane + 4-methyloctane | 0,05 | 0,026 |
| 70. | 3-Ethylheptane | 0,04 | 0,020 |
| 71. | p-Xylene | 0,05 | 0,027 |
| 72. | m-Xylene | 0,08 | 0,037 |
| 73. | 3-Methyloctane | 0,05 | 0,026 |
| 1 | 2 | 3 | 4 |
|---|---|---|---|
| Total paraffinic hydrocarbons, including: | 67.87 | 34.213 | |
| n-structure | 37.76 | 19.035 | |
| iso-structure | 30.11 | 15.178 | |
| Naphthenic hydrocarbons, including: | 30.99 | 15.622 | |
| five-membered | 20.35 | 10.258 | |
| six-membered | 10.64 | 5.364 | |
| Aromatic hydrocarbons | 1.14 | 0.575 |
The significant content (up to 33%) of naphthenes makes it possible to assess the gasoline distillates as valuable feedstock for catalytic reforming. It should be noted that, in terms of physicochemical properties and hydrocarbon composition, the Kazan gas condensate is completely identical to other condensates from fields of the Tomsk Region, in particular to the condensate of the largest gas-condensate field in the region, the Myldzhino field [2, 3].
Conclusions
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The physicochemical characteristics and the group and individual hydrocarbon composition of the gasoline fractions of the gas condensate from the Kazan field have been determined.
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On the basis of the group hydrocarbon composition, it has been established that the condensate has a methane–naphthenic character.
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It is noted that, in terms of physicochemical properties and material composition, the condensate studied does not differ from gas condensates of other fields of the Tomsk Region and can be used as feedstock for pyrolysis and catalytic reforming.
References
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M. I. Ivanova. Use of gas–liquid chromatography for determining the individual composition of straight-run gasolines boiling up to 150°C. Author’s abstract of a dissertation for the degree of Candidate of Chemical Sciences. Irkutsk, 1967.
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N. M. Smolyaninova, S. I. Smolyaninov, V. A. Kuznetsova, K. K. Stramkovskaya, and I. S. Karpenko. Collection “Problems of Chemistry.” Scientific Notes of the Tomsk State Pedagogical Institute, 26, 8, 1969.
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N. M. Smolyaninova, K. K. Stramkovskaya, L. A. Ponomareva, V. A. Kuznetsova, M. E. Shlykova, L. I. Skakun. Ibid., p. 15.