Study of Gas Condensate from the Urengoy Field
Abstract Generated abstract
This paper reports a technological characterization of stable gas condensate from the Urengoy gas condensate field, using hot stabilization followed by fractional distillation and analysis of physicochemical and group hydrocarbon composition. The condensate is described as low density, low viscosity, very low sulfur, free of resin asphaltene substances, and rich in gasoline and ligroin fractions, with 72.5 percent boiling below 200°C. Fractional analyses show high naphthenic content in low boiling gasoline cuts, appreciable aromatic content in higher gasoline and heavier fractions, and predominantly paraffin naphthenic composition above 200°C. The study evaluates potential products, concluding that gasoline fractions are suitable mainly as motor gasoline components, selected jet fuel cuts nearly meet specifications except for crystallization onset and flash point, illuminating kerosene can be obtained, and the residue above 200°C corresponds broadly to summer diesel fuel requirements.
Full Text
STUDY OF GAS CONDENSATE FROM THE URENGOY FIELD
K. K. STRAMKOVSKAYA, G. B. NEMIROVSKAYA, A. I. LEVASHOVA,
T. F. BULYCHEVA
(Presented by the scientific-methodological seminar of the organic departments
of the Faculty of Chemical Technology)
In the north of Tyumen Oblast lies the Urengoy gas-condensate field, with enormous reserves of natural gas and gas condensate.
To study the technological properties of this condensate, a sample was taken from a collector (during testing of well 58) after the pressure had been reduced to atmospheric. Since the stable condensate had a very high content of dissolved gases (up to C₅—21.04%), which made it impossible to conduct a general study, it was subjected to hot stabilization on an ARN-2 apparatus to such a state that the temperature at the top of the column became established at 28°C. This was achieved at a still temperature of 30°C while maintaining this regime for 6 hours.
The condensate stabilized in this way, with a dissolved-gas content of 8.59%, is characterized by a low density \((\rho_{4}^{20} — 0.7634)\), low viscosity \((\nu_{20} — 1.04\ \text{cSt})\), and molecular weight (116); it has low pour point (−46°C) and flash point (−78°C), contains no resin-asphaltene substances, and contains an insignificant amount of solid paraffin; sulfur content is 0.02%; the content of gasoline-ligroin fractions is exceptionally high—the yield up to 150°C is 60.0%, up to 200°C—72.5%; the end boiling point is 320°C.
Data on the fractional composition (rectification on ARN-2) and curves characterizing the properties of the 3% fractions are shown in Fig. 1.
The group hydrocarbon composition presented in Tables 1 and 2 indicates a significant content of aromatic hydrocarbons, with a maximum (24%) in the 122–150°C and 200–250°C fractions, and also a decrease in the amount of aromatics and an increase in n-alkanes upon transition to higher-boiling distillates. The content of naphthenic hydrocarbons falls as the temperature limits for fraction collection increase.
The low-boiling gasoline distillates (62–85°C and 62–105°C) are distinguished by a high content of naphthenic hydrocarbons (47–52%) and a small amount of aromatics (1–3%) and should be a good feedstock for catalytic reforming. As for the higher-boiling gasoline distillates, their feedstock qualities are considerably worse owing to the large quantity of constituents included in their
Fig. 1. Distillation curves of Urengoy gas condensate
Visible labels in the figure:
- Yield based on condensate, wt.%
- Residue
- \(t,^\circ\mathrm{C}\); M.W.
- \(\rho_4^{20}\)
- \(n_D^{20}\)
- Pour point, \(^\circ\mathrm{C}\)
- Sulfur content, %
- Curve labels: \(n_D^{20}\), \(\rho_4^{20}\), \(t_{\mathrm{av.\ boil.}}\), \(S\), \(S_{20}\), \(S_{50}\), \(\eta_{20}\)
Table 1
Group hydrocarbon composition of gasoline fractions of Urengoy condensate
| Fractions, °C | Yield, % of condensate | Aromatic hydrocarbons, wt % | Naphthenic hydrocarbons, wt % | Paraffinic hydrocarbons of normal structure, wt % | Paraffinic hydrocarbons of isostructure, wt % |
|---|---|---|---|---|---|
| 28—60 | 17.1 | 0 | 0 | 47 | 53 |
| 60—95 | 22.5 | 6 | 54 | 28 | 12 |
| 95—122 | 12.4 | 11 | 35 | 23 | 31 |
| 122—150 | 9.3 | 24 | 21 | 20 | 35 |
| 150—200 | 11.6 | 17 | 12 | 28 | 43 |
| 28—200 | 72.9 | 10 | 27 | 30 | 33 |
| 62—85 | 11.6 | 1 | 47 | 31 | 21 |
| 62—105 | 24.9 | 3 | 52 | 27 | 18 |
| 85—120 | 21.5 | 8 | 51 | 24 | 17 |
| 85—180 | 39.0 | 14 | 41 | 26 | 18 |
| 105—120 | 8.2 | 12 | 42 | 24 | 22 |
| 105—140 | 15.2 | 16 | 37 | 24 | 23 |
| 120—140 | 7.0 | 21 | 32 | 25 | 22 |
| 140—180 | 10.5 | 22 | 26 | 30 | 22 |
| 28—K. K. | 100.0 | 12 | 25 | 31 | 32 |
Table 2
Physicochemical properties and group composition of fractions boiling above 200°C of Urengoy condensate
| Indicators | 200—250°C | 250—300°C | 300—K. K. |
|---|---|---|---|
| Yield, wt % | 8.1 | 5.6 | 2.5 |
| Density, $d_4^{20}$ | 0.8309 | 0.8335 | 0.8340 |
| Molecular weight | 183 | 202 | 205 |
| Pour point | −35 | −10 | 5 |
| Viscosity, cSt at 20°C | 3.40 | 7.80 | 11.60 |
| Viscosity, cSt at 50°C | 2.10 | 3.15 | 4.80 |
| Sulfur content, % | 0.018 | 0.035 | 0.042 |
| Hydrocarbon content, wt %: paraffin-naphthenic | 76 | 80 | 78 |
| Hydrocarbon content, wt %: aromatic | 24 | 20 | 22 |
| Including: group I | 15 | 8 | 6 |
| Including: group II | 6 | 4 | 4 |
| Including: group III | 3 | 7 | 9 |
Continuation of Table 2
| 1 | 2 | 3 | 4 |
|---|---|---|---|
| IV group | absent | 1 | 3 |
| Resins and intermediate fractions | absent | absent | absent |
| Carbon distribution, %: | |||
| $C_{\mathrm{a}}$ | 9 | 12 | 13 |
| $C_{\mathrm{n}}$ | 44 | 39 | 37 |
| $C_{\mathrm{p}}$ | 47 | 49 | 50 |
| Number of rings in the molecule: | |||
| $K_{\mathrm{a}}$ | 0.18 | 0.30 | 0.43 |
| $K_{\mathrm{n}}$ | 1.03 | 0.81 | 0.64 |
| $K_{\mathrm{tot}}$ | 1.21 | 1.11 | 1.07 |
Characteristics of commercial products
| Fraction, °C | Yield, % of condensate | Density, $\rho_4^{20}$ | Viscosity, cSt at 20°C | Viscosity, cSt at 50°C | Sulfur content, % | Pour point | Flash point in closed crucible |
|---|---|---|---|---|---|---|---|
| Gasoline fractions | Gasoline fractions | Gasoline fractions | Gasoline fractions | Gasoline fractions | Gasoline fractions | Gasoline fractions | Gasoline fractions |
| 28—85 | 29.7 | 0.6850 | — | — | absent | — | — |
| 28—120 | 51.2 | 0.7310 | — | — | " | — | — |
| 28—150 | 61.3 | 0.7418 | — | — | " | — | — |
| 28—200 | 72.9 | 0.7605 | — | — | " | — | — |
| Jet fuel | Jet fuel | Jet fuel | Jet fuel | Jet fuel | Jet fuel | Jet fuel | Jet fuel |
| 120—240 | 28.5 | 0.7915 | 1.65 | 6.20* | 0.01 | — | 25 |
| 120—280 | 33.4 | 0.7960 | 1.81 | solidifies* | 0.01 | — | 28 |
| Kerosene fractions | Kerosene fractions | Kerosene fractions | Kerosene fractions | Kerosene fractions | Kerosene fractions | Kerosene fractions | Kerosene fractions |
| 150—280 | 23.3 | 0.8070 | — | — | 0.01 | — | 35 |
| 150—320 | 26.6 | 0.8190 | — | — | 0.01 | — | 28 |
| Diesel fuel | Diesel fuel | Diesel fuel | Diesel fuel | Diesel fuel | Diesel fuel | Diesel fuel | Diesel fuel |
| Residue above 200 | 16.2 | 0.8325 | 5.35 | 2.83 | 0.03 | −20 | 36 |
* Viscosity at a temperature of −40°C.
composition of aromatic hydrocarbons. This reforming feedstock, apparently, will require preliminary dearomatization.
In the study of the group hydrocarbon composition of 50-degree fractions boiling above 200°C (Table 2), the presence of ...
presence of aromatic hydrocarbons in an amount of 20–24%, including 15–6% accounted for by group I aromatics with a refractive index of 1.4940–1.5280. Depending on the temperature limits for taking the fractions, the content of paraffin–naphthenic hydrocarbons is 76–80%. The same table gives data characterizing the structural-group composition of the 50-degree fractions.
The characteristics of the products of direct distillation (commercial products) are given in Table 3.
Gasoline fractions, with a high yield, are characterized by the absence of sulfur and by low octane numbers (45–72 neat and 73–86 with the addition of TEL—2.7 g/kg) and can be recommended only for use as components of motor gasoline.
The fractions 120–240°C and 120–280°C, tested as jet fuel, correspond in all indicators, except the crystallization-onset temperature and flash point, to fuels of grades TS-1 and T-1.
Kerosene fractions 150–280°C and 150–320°C cannot be used as tractor fuel because of their low octane numbers.
Table 3
of condensate from the Urengoy field
| Product | Cloud point, °C | Crystallization onset, °C | Iodine number, g I₂ per 100 g of fuel | Octane number, neat | Cetane number | Aromatic hydrocarbon content, % | Coking capacity, % | Smoke point, mm | Acidity, mg KOH per 100 ml of fraction |
|---|---|---|---|---|---|---|---|---|---|
| Fractions | |||||||||
| — | — | — | — | 72.5 | — | 0.5 | — | — | absent |
| — | — | — | — | 67.3 | — | 3.6 | — | — | 0.24 |
| — | — | — | — | 60.9 | — | 7.7 | — | — | 0.39 |
| — | — | — | — | 45.0 | — | 10.0 | — | — | 0.47 |
| Fuel | |||||||||
| — | — | −55 | 0.47 | — | — | 21 | — | does not smoke | 0.73 |
| — | — | −39 | 0.69 | — | — | 22 | — | ” | 1.21 |
| Distillates | |||||||||
| — | −31 | — | — | 22 | — | 22 | — | 29 | 1.75 |
| — | −15 | — | — | 19 | — | 22 | — | 28 | 2.23 |
| Fuel | |||||||||
| — | — | — | — | — | more than 50 | — | traces | — | 1.77 |
numbers. But from this condensate an illuminating kerosene can be obtained with a yield of 26.6%.
The residue boiling above 200°C, according to the principal indicators, corresponds to GOST for summer diesel fuel.