CS252524B1 - Process for producing n-alkanes - Google Patents

Abstract

n-Alkanes are produced by dewaxing products with a boiling point in the range of 200 to 450 °C with an n-alkane content of at least 20% by weight from hydrocracking petroleum products with a boiling point above 300 °C (vacuum distillates, slags, extracts and their mixtures).

Description

252524

The present invention relates to a process for producing n-alkanes C10 to C50, in particular n-alkanes C1 to C18, by dewaxing fractions from unconventional hydrocarbon feedstocks with a low alpha content and only a low sulfur and nitrogen content. Then, unlike a similar petroleum fraction, it does not require preliminary pretreatment prior to use for the production or recovery of n-alkanes by adsorption processes.

Much attention has already been paid to hydrocarbon hydrolysis (Brcoks CT: Ing. Chem. Tundam 6, 236 (1967); CA 68,23263 f; Kohloefl K, Bažant V: J. Catal. 10, 140 ( Sinfelt: Catal. Rev. 3, No 2, 175 (1969); Eiichii Kikuchi et al., J. Catal., 22, 226 (1971); Japanese Pat., 7396477 (1973); i.) on conventional hydrogenation catalysts, in particular noble metals (Pt, Rh, Ru, Pd), but also nickel, cobalt, molybdenum, tungsten, uranium, chromium and iron, generally on acidic supports (alumina, aluminosilicates and (i) but did not pay substantial attention to the conversion or potential conversion of isoalkanes and cycloalkanes to n-alkanes, but the hydrogenolysis of the organic and hydrocarbon compounds of sulfur and nitrogen, respectively, to form hydrocarbons and hydrocarbons, respectively, was relatively thoroughly studied. the ammonia also introduced by the catalysts, whether in the form of metal on supports, oxides or sulphides [U.S. Pat. No. 3,126,476 (1976), Ozimek et al., Chem. Stosow. 19, 97 (1975); Sotani: Rev. Phys. Chem. Me p. 48, 9 (1976); C.A. 86, 54697 b; Benson et al., Hydrocarbon Process 53, No. 4, 81 (1974)], paying attention to the uptake of hydrogen sulfide and ammonia from the gaseous moieties of hydrogenolysis.

Also, the ancient Is known [Cernožukov N. I. Technologija pererabotki nefti i gaza, 'part 3. Izdatelstvo "Chimija" Moscow 1978; Ogorodnikov S. K. (ed.): Spravočnik nefte-chimika 1. a 2. diel. "Chimija" Leningrad (1978); Indian Pat. 152, 240 (1983); Lactica i .: Gaziva Maziva 22, No 5-6, 253 (1983); Eng. Chem. Art.-No. Res. Dev. 23, 634 (1984); Isunajlov et al .: Chim. Technol. Topel No. 6, 32 (1984); U.S. Pat. 4, 455, 444, et al., That petroleum fractions are used for dewaxing, either with a urea-adduct process or with 5A molecular sieves (CaA, NaX and i. diesel fuel fractions or wider gas oil fractions. In the case of obtaining n-hexane, this is a narrow fraction of primary gasoline. However, all the raw materials need to be hydrofinished, depending on the choice, before or after depot-refining. The limiting factor is sulfur, aromatics and unsaturated hydrocarbons. For example, for an adsorption process for the production of n-alkanes in a gaseous phase, which is relatively energy intensive, a maximum of 0.2 wt. sulfur and 2.10% 4% nitrogen, but for a more efficient and energy-efficient process in the liquid phase, it is no more than 2.10-4 sulfur and 1.10 4% nitrogen, with minimal content being present in all varieties It is also well known about hydrocracking that it mainly utilizes the production of light petroleum products by catalyzing the decomposition of the heavier feedstock in the presence of hydrogen, and that there are numerous modifications to hydrocracking production units. which are intended for production, use single-stage and two-stage processes with catalyst bed layers, both fluidized and suspended catalysts, and a one-step variant is usually used if the hydrocracking is mainly diesel fuel and two-stage, for obtaining 1'ahšíchproduktov.

Its products are, in addition to hydrogen sulfide and α-monoacide, which are carefully removed from the recirculating gas, gases C1-C4, light benzine, which has an isoalkanic character and, therefore, a high octane number (OMS = 82-84). Typically, heavy gasoline has a high content of cycloparaffinic hydrocarbons and is therefore also an excellent raw material for the catalytic reforming of petrol to obtain a reformate with an aromatic content above 70%. It is also well known for kerosene hydrocracking. "Chimiya", Le-ningrad (1978), Jurcacko; Oil and Coal 27.69 (1985); me p. pat. 60 08392 (1985)] that it contains few aromatics and that it practically does not contain sulfur and alkenes. Similarly, gas oil has a low sulfur content and a reduced aroma content. Also, considerable attention is paid to hydrocracking catalysts [Gofdfarb. et al., Kinetic and Catalog, 25, 370 (1984); Strobel et al .: Why. Int. Conf. Coal Sci 1983, p. 216; J.Catal. 22, 226 (1971); 31, 264 (1973); jap, pat. 73, 96477 (1973); C.A. 80, 95205, except for the investigation of the content of alkanes in individual product fractions, depending on the conditions and other parameters of the hydrocracking of the oil fractions.

However, according to the present invention, a process for producing n-alkanes by dewaxing, such as selective adsorption on molecular sieves through desorption or urea through the intermediate n-alkanes and urea adducts, is carried out by starting the dewaxing fraction with a range of 200 ° C to 450 ° C with a n-alkanes content of at least 20% by weight, a hydrocracking product of petroleum fractions having a boiling point above 300 ° C and / or an extract of the selective refining of oils and / or gums. The advantage of using the petroleum fraction hydrocracking products of the present invention, based on the surprising finding that the hydrocracking of petroleum fractions, the dark distillates, is markedly higher in n-alkanes than in similarly similar fractions and, in addition, low in aro-5 content. 252524 mint and especially very low sulfur content. In contrast, the lower-boiling fractions of hydrocracking have a higher content of isocyanates than the similar petroleum fractions. This is related to the lower bond strength of C-C and C-H at the branches of the isoalkanes and the bonding of the alkyl to the rings, dukcnéiio effect of alkylskuipine. These carbon monoxide molecules are more likely to undergo their catalytic-thermal pestonia, including hydrogenolysis. This also allows the medium and higher hydro-cracking fractions to be used directly for the production of alanines, to increase the performance of the plant-alkanes, but also to further reduce the solidification temperature and hence the quality of the decanted hydrocracking fractions.

By oil fraction is meant primary avacuum gas oil, vacuum petroleum distillate, especially vacuum paraffin oil or sulfur-paraffin oil as well as oil.

According to the present invention, the product of the pre-physico-chemical processing of the oil is the extracts from the refining of oils, slag, heavy oil from the deasphalting of residual oil fractions, gas oils and heavy distillates from thermal cracking products and thermal coking. The spatial rate of cracking depends on the quality of the hydrocracking feed, the reaction temperature of the hydrogen partial pressure, the type and activity of the catalyst, and the desired hydrocracking depth of the hydrocarbon feedstocks. It is possible to operate at temperatures of 290 to 500 ° C, but a temperature in the range of 380 to 430 ° C is usually most suitable.

Hydrocracking catalysts are most commonly metal or compound VI based. aVIII. groups of the periodic system of elements, generally on acidic carriers such as alumina, aluminosilicates naturally, but mostly synthetic, further oxides: aluminum, siliceous, titanium and zirconium. The metal compounds are most often in the form of oxides and especially sulfuric. Of the metals (and compounds thereof) most important are nickel, cobalt, molybdenum, tungsten, uranium, chromium, platinum and palladium. Fewer and more useful are iron and its compounds. Rare metals are relatively highly efficient but technically and economically more affordable: platinum, palladium, ruthenium, rhenium and radium.

The content of single metal or multi-metal in the hydrocracking catalyst ranges from 0.2 to 35% by weight. The more sophisticated the metal component, the smaller its amount in the catalyst. In the case of more conventional catalysts such as molybdenum oxide or sulfides. iron, cobalt, and alumina, silica, titanium dioxide, and zirconium oxide are, for example, about 2.5% CoO, 8% MoO3.15% SiO2 and about 75% Al2O3. Then 6% Ni and 15 ° W in the form of oxides or sulphonating aluminosilicate; Nial or Co, W and Mo oxides or sulfides in a total amount of 16% on the crystalline aluminosilicate and the like.

Other known effective hydrocracking catalysts may also be applied. In a lesser extent, the catalysts may also contain additions to other elements.

Hydrocracking also releases the sulfur, nitrogen in the hydrogen sulfide and ammonium, and other impurities such as phosphorus and the like. They are most often removed by scrubbing recirculated hydrogen. For the production of n-alkanes, a number of fractions of the hydrocracking product can be used, but in view of the content of n-alkanes as well as the usual needs, a fraction of 200 to 360 ° C and 200 to 340 CC, respectively, is most suitable. . From higher fractions such as 360 ° C, n-alkanes can be removed by, in particular, urea dewaxing. Further characteristics and other advantages of the process of the invention are evident from the examples. EXAMPLE 1 Sulfur-paraffinic petroleum petroleum distillate is fed to continuously hydrocracking on a nickel-molybdenum catalyst (containing Ni + Mo = 18.3% by weight) by the naamorphic aluminosilicate carrier, provided by the spatial 1.3h -1, heat 415 + 5 ° C in the presence of hydrogen and a pressure of 14.5 MPa. The crude product obtained from the hydrocracking reactor (after the addition of hydrogen) contains 0.12% ammonia; 2.11% hydrogen sulfide; 0.40% gas-6,65% propane / butane / isobutane; 01% 1 of light gasoline, 50,25% of gasoline, 10,25% of kerosene, and 17,08% of gas oil Raw product, its individual components are isolated, Ammonium, hydrogen sulphide and Cl-Ca are removed The mixture is separated from a recirculated gas (hydrogen), whereupon a mixture of C3-C8 hydrocarbons is separated by distillation, rectifying a further fraction of hydrocarbons, and thus a fraction having a temperature of 260 DEG-360 DEG C. is isolated. solidification, a = -7 ° C, density at 20 ° C = 781.2 kg m3, medium molar mass - 232.4 g.mol-1, sulfur content = 1.10 ~ 4% by weight; n-alkanes C11-Ct-66.4%, 6.2% aromatics, the remainder being isoalkanes and cycloalkanes.

The content of n-alkanes is determined by known methods [Anal. Chem. 34, 82 (1962); Nelson, K. H., Grimes, M.D., and Heinrich, B.J .: Anal. 29, 1026 (1957)], additionally combined with liquid-gas chromatography to determine the distribution of individual n-alkanes fractions, the principle of the method being the adsorption of n-alkanes dissolved in isooctane, used (added to the sample) as solvent The sap is filtered off, the solvent is evaporated, the residue remaining from the branched paraffins is weighed. The content of n-alkanes in the sample is determined by the weight difference between the nonadsorbed residue. and the flood sample.

Similar but less accurate results are

Claims (1)

252 7 are based on methods based on the formation of crystals of n-alkanes with urea [Domask, Kobl .: Petroleum Ref. 34, No. 4, 128 (1955); Zimmerschield et al., Ind. Chem. Egy.42, 1300 (1950); Schliessler, Flitter, J. Am. Soc. 74, 1720 (1952)]. However, these methods are suitable for the determination of even higher alkanes (over C24). The distillation residue, i.e., the hydrocarbon mixture of 360 ° C, has a middle mole. weight 402.8grams. mole-1. The thus obtained fraction of 200 to 360 ° C in addition to the production or recovery of n-alkanes by liquid phase liquid-phase sieves (processes: Molex, Parex) instead of the petroleum hydrogenated fraction of t.alpha. 200 to 360 ° C, obtained from a similar West Siberian sulfur-paraffinic oil containing 28.3% of n-alkanes, 25.3% of an asia aromatic of 0.04% by weight. This, in addition to the high sulfur content and its compounds, and the aromatics prior to dewaxing in the liquid phase, requires hydrotreating. EXAMPLE 2 Vacuum petroleum distillate from West Sulfur-paraffinic Crude Oil is fed continuously to hydrocracking on a sulphide nickel-molybdenum-tungsten aluminosilicate catalyst with a metal component content of 21.3% by weight. at a temperature of 1.5 hours -1 at 395 ± 5 ° C in a hydrogen atmosphere at 15 MPa. The crude product obtained from the hydrocracking reactor contains 0.12% ammonia after the hydrogen has been taken off; ; 0.31% of Ci-C2 gases; 3.00% of propane with n-butane and isobutane; 5.69% of light gasoline; 23.85% of heavy-duty gasoline; 25.34% of petroleum and 39.66% of gas In addition to the removal of ammonia, hydrogen sulfide, the isolation of methane, ethane, and the propane-butane fraction, which can also be used as a valuable pyrolysis feed, especially after isolation of isobutane, light gasoline, which is isocyanic and octane. In addition, a fraction of 200 to 360 cC / 101 kPa, which has a mean gas fraction of 73% aromatics and a mercaptan number determined by the research method 101, is recovered by the method of Method 83, the heavy benzene, which, after catalytic reforming at 508 ° C, contains 73% aromatics. molar mass mp-233 ° C, sulfur content = 1.4.10-4%, n-alkanes content of 52.6%, 7.2% aromatics, with the remainder they form isoalkanes and cycloalkanes. This fraction is directly directed to the production or recovery of n-alkanes by means of molecular sieves - CaA or NaX zeolites, as well as adsorbents and mixtures of n-alkanes Cg - such as desorbent and ammonia (temperature 320 ++ 5 ° C, pressure 0.17 MPa), n-alkanes reach 91%. Distillation residue from the hydrocracking product, i.e. boiling above 360 ° C / 101 kPamma mole. weight 404 g. mole-1; density at 20 ° C = 860 kg. m-3; sulfur content == 1.8.10-4%; Elemental analysis: C = 85.51%, H = 14.15%; Alkanocycloalkane = 96.4% by weight of monoaromatics = 1.5% by weight; di- and triaromates = 0.43% by weight; % and the residue = 0.5 wt. SUBJECT OF PRODUCTION OF N-ALANKS BY DEFINING, AS SELECTIVE ADDRESSING ON Molecular Sieves, Following Desorption Of Urea Through Intermediate Adducts Of N-Alkanes With Urea, characterized by the fact that the feedstock for dewaxing is FILLED is a boiling fraction of in the range of 200 ° C to 450 ° C with a n-alkanes content of at least 20% by weight, of the hydrocracking product of petroleum fraction boiling above 300 ° C and / or extracts from selective refining of oils and / or gums. Severografla, n. P., Race 7, Oeaa Bridge 1,40 Kís