METHOD FOR PRODUCING GASOLINES OR AROMATIC COMPOUND CONCENTRATES WITH DIFFERENT DISTRIBUTION OF HYDROCARBON, OXYGENATE AND OLEFIN-CONTAINING FRACTIONS TO THE REACTOR BEDS

Abstract

The invention refers to the method for producing gasolines or aromatic compound concentrates, where three streams are used as feedstock, one of which includes hydrocarbon fraction, the second stream includes oxygenate, the third stream includes olefin-containing fraction with one or more olefins selected from the group consisting of ethylene, propylene, normal butylenes, isobutylene, in total from 10 to 50 wt %, and where three reaction zones filled with zeolite catalyst are used, with distribution of hydrocarbon fraction and oxygenate to the first reaction zone, and with olefin-containing fraction distributed over the three reaction zones, with the third stream mass fraction distributed to the final reaction zone higher than the mass fraction of the third stream distributed to each of the previous reaction zones. This method allows to increase the yield of C.sub.5+ hydrocarbons, enhance n-hexane and n-heptane conversion, reduce benzene content in the product, avoid recycling of gaseous products and decrease consumption of oxygenates.

Claims

1. Method of producing liquid hydrocarbon product containing aromatic compounds, where three streams are used as feedstock: the first stream includes the hydrocarbon fraction, the second stream includes oxygenate, and the third stream includes the olefin-containing fraction, where: a. The olefin-containing fraction includes one or more olefins from the group including ethylene, propylene, normal butylenes, isobutylene, in total amount from 10 to 50 wt %; b. Three reaction zones filled with zeolite catalyst are used; c. The first stream is fed to at least one reaction zone; d. The second stream is fed to the first reaction zone; e. The third stream is distributed between three reaction zones, with the mass fraction of the third stream distributed to the final reaction zone being higher than the mass fraction of the third stream distributed to each of the previous reaction zones; f. Provided that the product stream from the first reaction zone is supplied to the second reaction zone, and the product stream from the second reaction zone is supplied to the third reaction zone.

2. The method as per the claim 1 of the formula, where the liquid hydrocarbon product containing aromatic compounds is represented by gasoline, if aromatic compound content is less than 46 wt %, or the liquid hydrocarbon product containing aromatic compounds is represented by aromatics concentrate, if aromatic compound content is higher than 46 wt %.

3. The method as per the claim 1, where the first stream is preferably supplied to the first reaction zone.

4. The method as per the claim 1, where the third stream is distributed between the three reaction zones as follows: 10-30 wt %/20-35 wt %/40-70 wt %.

5. The method as per the claim 1, where the hydrocarbon fraction contains normal paraffins in the amount of 15-24 wt %, isoparaffins in the amount of 28-56 wt %, naphthenes in the amount of 22-40 wt %, the rest are aromatic hydrocarbons and olefins.

6. The method as per the claim 1, where the hydrocarbon fraction contains from 0 to 80 wt % of C.sub.6 hydrocarbons, preferably from 23 to 46 wt % of C.sub.6 hydrocarbons, most preferably from 36 to 46 wt % of C.sub.6 hydrocarbons.

7. The method as per the claim 1, where the hydrocarbon fraction contains from 0 to 70 wt % of C.sub.7 isoparaffins, preferably from 26 to 50 wt % of C.sub.7 isoparaffins, most preferably from 26 to 38 wt % of C.sub.7 isoparaffins.

8. The method as per the claim 1, where the hydrocarbon fraction may be selected from the group including straight-run gasoline, natural stable gasoline, light gas condensate, gasoline fraction with boiling range of about 62-85° C., raffinate, and mixtures thereof.

9. The method as per the claim 1, where the first olefin-containing fraction has a mass fraction of C.sub.5+ hydrocarbons from 0 to 10.0 wt %, preferably from 0 to 5.0 wt %.

10. The method as per the claim 1, where the olefin-containing fraction may include C.sub.5+ olefins, such as pentenes, hexenes.

11. The method as per the claim 1, where the olefin-containing fraction has a volume fraction of hydrogen sulfide from 0.0 to 0.005%.

12. The method as per the claim 1, where the olefin-containing fraction may include hydrocarbon components other than olefins, such as methane, ethane, propane, butane, and may contain nonorganic gases, such as hydrogen, nitrogen.

13. The method as per the claim 1, where the olefin-containing fraction comprises 0.5-8.0 wt % of hydrogen, preferably 2.3-8.0 wt % of hydrogen.

14. The method as per the claim 1, where the olefin-containing fraction may include C.sub.5+ olefins, such as pentenes, hexenes.

15. The method as per the claim 1, where the olefin-containing fraction is selected from the group including dry gas of catalytic cracking, wet gas of catalytic cracking, other catalytic cracking gases and their fractionation products, exhaust gas from the coker unit, Fischer-Tropsch synthesis gases, and mixtures thereof.

16. The method as per the claim 1, where the olefin-containing fraction is selected from the group including propane-propylene fractions, butane-butylene fractions, thermal cracking gas, visbreaking gas, hydrocracking exhaust gases, pyrolysis gas, catalytic reforming exhaust gas, and mixtures thereof.

17. The method as per the claim 1, where the olefin-containing fraction includes dry gas of catalytic cracking and contains from 25 to 40 wt % of C.sub.2-C.sub.4 olefins.

18. The method as per the claim 1, where the oxygenate is selected from the group including aliphatic alcohols, such as methanol, ethanol, crude methanol, technical methanol, ethanol; simple esters, such as dimethyl ether; and mixtures thereof, including mixtures with water.

19. The method as per the claim 1, where the oxygenate may contain impurities, such as aldehydes, carboxylic acids, compound ethers.

20. The method as per the claim 1, where the process pressure is from 1.5 to 4.0 MPa, preferably from 2.2 to 2.7 MPa.

21. The method as per the claim 1, where the weight hourly space velocity is 0.5-10 h.sup.−1, preferably 1-3 h.sup.−1.

22. The method as per the claim 1, where the stream temperature at the inlet to the first/second/third reaction zones is 340-450° C./340-450° C./340-450° C.

23. The method as per the claim 1, where the weight hourly space velocity is from 0.5 to 10 h.sup.−1, preferably 1-3 h.sup.−1.

24. The method as per the claim 1, where the stream temperature at the inlet to the first/second/third reaction zones is 340-370° C./340-370° C./340-370° C.

25. The method as per the claim 1, where the weight hourly space velocity is from 0.9 to 10 h.sup.−1, preferably 1-3 h.sup.−1.

26. The method as per the claim 1, where the stream temperature at the inlet to the first/second/third reaction zones is 390-450° C./390-450° C./390-450° C.

27. The method as per the claim 1, where the weight hourly space velocity is from 0.1 to 0.9 h.sup.−1.

28. The method as per the claim 1, where the catalyst distribution over the reaction zones is 15-25 wt %/30-33 wt %/35-50 wt % of the total catalyst amount for the first/second/third reaction zones, respectively.

29. The method as per the claim 1, where the mass of the catalyst distributed to each subsequent reaction zone is higher than the catalyst mass distributed to each previous reaction zone.

30. The method as per the claim 1, where the hydrocarbon fraction is 38-79 wt % of the supplied feed.

31. The method as per the claim 1, where the olefin-containing fraction is 13-57 wt % of the supplied feed.

32. The method as per the claim 1, where the oxygenate is 3.8-8.0 wt % of the supplied feed.

33. The method as per the claim 1, wherein the zeolite catalyst includes: a. ZSM-5 type zeolite with modulus SiO.sub.2/Al.sub.2O.sub.3 from 43 to 95, in the amount of 65 to 80 wt %; b. Sodium oxide in the amount of 0.04 to 0.15 wt %; c. Zinc oxide in the amount of 1.0 to 5.5 wt %; d. Oxides of rare earth elements in total amount of 0.5 to 5.0 wt %; e. Binder comprising silicon dioxide, aluminum oxide or mixtures thereof.

34. The method as per the claim 33, where the zeolite catalyst is free of platinum metals.

35. The method as per the claim 33, where the rare earth elements are selected from the group including lanthanum, praseodymium, neodymium, cerium, as well as mixtures thereof.

36. The method as per the claim 1, where the reaction takes place in gas phase in static layer of catalyst.

Description

EXAMPLES

[0115] The results achieved are demonstrated below in examples 1-12.

[0116] Examples 1-6, 12 and comparative example 7 demonstrate the gasoline production case. Examples 8-11 show the possibility of obtaining aromatic compound concentrates.

[0117] The proposed process allows to produce liquid hydrocarbon product which can be used as gasoline or aromatic compound concentrate.

[0118] Gasoline and aromatic compound concentrate differ in total aromatics content in the product. Some states and companies limit the maximum total aromatics content in commercial gasoline to 35 vol. % (approximately 38-40 wt % of aromatics). Specific environmental regulations allow up to 40-46 wt % of aromatics in commercial motor gasoline. In this regard, the liquid hydrocarbon product with total content of aromatics below 46 wt % refers to gasoline. In particular, the proposed method allows producing liquid hydrocarbon product, which can be sold as commercial motor gasoline without additional compounding. Liquid hydrocarbon product with total content of aromatic hydrocarbons above 46 wt % refers to aromatic compound concentrates. In particular, the proposed method allows producing liquid hydrocarbon product, which can be used as high-octane aromatics concentrate to be used as the main component in motor gasoline compounding.

[0119] It should be noted that depending on the state or enterprise, the maximum allowable concentration of aromatics in commercial gasoline may differ from 38-46 wt %.

[0120] Concentration of aromatics in obtained liquid hydrocarbon product can be controlled by means of several parameters. Specifically, an increase in supplied feed temperature and/or decrease in supplied feed mass rate results in increase in aromatics mass fraction in the obtained liquid hydrocarbon product.

[0121] Examples 8-11 demonstrate production of aromatic compound concentrates with more than 46 wt % of aromatics at temperatures of 390-450° C. and/or at weight hourly space velocity from 0.1 to 0.9 Such aromatics concentrates may be used as the main component in compounding (blending) of commercial gasolines. It is also possible to use aromatic compound concentrates for further processing by petrochemical methods.

[0122] Comparative example 7 differs from the invention examples by the fact that no olefin-containing fraction is supplied to the reaction zones. Hence, oxygenate consumption for the process is not reduced due to partial oxygenate substitution with olefin-containing fractions (i.e. substitution of oxygenate with olefin-containing fractions is 0%). The proposed invention examples 1-6, 12 and 8-11 illustrate that it is possible to partially substitute oxygenates with olefin-containing gases while maintaining the yield, product quality and feedstock processing depth.

[0123] In examples 1-12, the yield and other process parameters are shown for liquid hydrocarbon product not containing dissolved C.sub.1-C.sub.4 gases (C.sub.5+ hydrocarbon fraction of the product). This is related to the fact that liquid hydrocarbon products obtained and stored under different conditions may contain different amounts of dissolved gases. At the same time, the dissolved gases content may change unevenly over time, changing the chemical composition. This can lead to inadequate comparison of the yield and the product quality in different experiments, especially when comparing results of different refineries. Therefore, it is preferable to compare the parameters of the product free of dissolved gases. However, it should be noted that depending on the specific production objectives, the liquid hydrocarbon product may contain not only C.sub.5+ hydrocarbons, but also various amounts of dissolved C.sub.1-C.sub.4 gases.

[0124] Whereas C.sub.5+ hydrocarbons (hydrocarbons with five or more carbon atoms) are the main component of liquid hydrocarbon product, the yield of the liquid hydrocarbon product will increase simultaneously with the yield of C.sub.5+ hydrocarbons.

[0125] In examples 1-11, a catalytic unit including three reactors connected in series with total catalyst loading of up to 9 liters are used. The reactors are designated as the first, second and third reaction zones, R.sub.101, R.sub.201, R.sub.301, respectively.

[0126] In terms of the structure, reactors are mostly of adiabatic type, heat exchange between catalyst layer and vessel is minimized. Catalyst baskets are placed in the reactor vessel so that a gap (about 2 mm) is left between the basket wall and the solid vessel. Each reactor is installed heating elements with thermostats with three heating zones. Three thermocouples are placed between surfaces of the heating elements and outside surface of the reactor vessel. Opposite them, thermocouples are also placed on the inside wall of the reactor basket. There is also an air gap between the thermostat inside surface and the reactor outside surface, not exceeding 3-4 mm. Constant temperature difference between thermocouples at the reactor outside wall and opposite thermocouple at the reactor basket inside surface is maintained by control circuits.

[0127] They started to sample the liquid and gaseous products for test 4 hours after the start of the feed supply.

[0128] Table 1 shows the chemical composition of hydrocarbon fractions used in examples 1-12. Specifically, 62-85° C. fraction (fr. 62-85° C.) represents benzene-forming portion of the catalytic reforming feedstock (approximate boiling range: 62-85° C.). Raffinate is normally a mixture of mainly gasoline-range hydrocarbons that are a by-product gasoline fraction selected from an aromatic hydrocarbon extraction unit. For instance, the raffinate may be an extraction by-product of the benzene-toluene fraction. The raffinate may also be an extraction istillation by-product of the toluene-xylene fraction.

[0129] Table 2 shows the composition of olefin-containing fractions used in examples 1-12. The used olefin-containing fractions can be considered, specifically, as a model of dry gas of catalytic cracking sample (DGCC compositions are obtained as a result of refinery's data averaging over several months of catalytic cracking unit operation). However, it should be noted that olefin-containing fractions nomination and origin process may vary depending on refinery and region. Attention should be paid to chemical composition of the fraction used, specifically, the olefin-containing fraction should include C.sub.2-C.sub.4 olefins in total amounts of 10 to 50 wt %. Preferable mass fraction of C.sub.5+ hydrocarbons in the olefin-containing fraction is not more than 5.0 wt %. Preferable volume fraction of hydrogen sulfide in the olefin-containing fraction is not more than 0.005%. The olefin-containing fraction may contain hydrogen in concentration from 0.5 to 8 wt %, preferably from 2.3 to 8 wt % of hydrogen.

[0130] Methanol of technical grade “A” as per GOST 2222-95 is used as oxygenate in examples 1-3, 6-8 and 11-12. Examples 4 and 10 use dimethyl ether (DME), 99%. Examples 5 and 9 use 95% ethanol.

[0131] Table 3 shows the composition of zeolite catalysts used in examples 1-12.

[0132] Table 4 shows the conditions and main parameters of examples 1-7. The hydrocarbon fraction in examples 1-7 is supplied to the first reaction zone. Example 12 repeats conditions of example 1, with the exception that hydrocarbon fraction in example 12 is distributed over three reaction zones in the ratio of 50/25/25 wt %. Experiments with the invention were run at pressures of 15-40 bar (1.5-4.0 MPa), preferably 22-27 bar (2.2-2.7 MPa). The oxygenate substitution % parameter (percentage of oxygenate substitution with olefin-containing fractions) is calculated according to formulas (4) to (6) of this Description.

[0133] Table 5 and Table 7 show the composition of liquid hydrocarbon product in examples 1-7.

[0134] Example 12 shows the yield of C.sub.5+ liquid hydrocarbon product of 77.7 wt % per hydrocarbon fraction supplied with product RON of 90.8 and aromatics content of 29.6 wt % (the data are provided for liquid hydrocarbon product free of dissolved gases).

[0135] Table 7 shows gasoline composition after separation of gaseous products from it, with dissolved gases content in gasoline stabilized at 3-5 wt % (stabilized liquid hydrocarbon product). Such product can be considered as a stable gasoline or high-octane base for production of commercial gasoline. The products in Table 8 contain from 3 to 5 wt % of dissolved C.sub.1-C.sub.4 gases. However, depending on the particular production objectives, the liquid hydrocarbon product may contain various amounts of dissolved C.sub.1-C.sub.4 gases. In particular, in process of production of motor gasoline, it is usually permitted to have up to 3-5 wt % of dissolved gases in summer gasoline and up to 5-7 wt % of dissolved gases in winter gasoline. The desired amount of dissolved gases in the product is controlled by standard fractionation and stabilization methods.

[0136] Table 5 shows the product compositions for the same experiments as referred to in Table 7, but Table 5 shows the composition of liquid hydrocarbon products free of dissolved C.sub.1-C.sub.4 gases (C.sub.5+ hydrocarbon fraction of the product). Normally, the refineries do not need to obtain a product free of dissolved gases. However, the yield and composition comparison of C.sub.5+ products are more indicative. Liquid hydrocarbon products obtained and stored under different conditions may contain different amounts of dissolved gases. At the same time, the dissolved gases content may change unevenly over time, changing the chemical composition. This can lead to inadequate comparison of the yield and the product quality in different experiments, especially when comparing results of different refineries. Therefore, it is preferable to compare the parameters of the product free of dissolved gases. However, it should be noted that depending on the particular production objectives, the liquid hydrocarbon product may contain not only C.sub.5+ hydrocarbons, but also various amounts of dissolved C.sub.1-C.sub.4 gases, specifically, as shown in Table 7.

[0137] Whereas C.sub.5+ hydrocarbons (hydrocarbons with five or more carbon atoms) are the main component of liquid hydrocarbon product, the yield of the liquid hydrocarbon product will increase simultaneously with the yield of C.sub.5+ hydrocarbons.

[0138] Table 6 shows the conditions and main parameters of examples 8-11. Hydrocarbon fraction in examples 8-11 is supplied to the first reaction zone. The experiments were run at pressures of 22-27 bar (2.2-2.7 MPa).

[0139] Gaseous product in examples 1-12 included mainly hydrocarbons and nitrogen. The nitrogen source is the olefin-containing fractions supplied to the reaction. In the invention examples, the gaseous product content of C.sub.3+ hydrocarbons (mainly propane) was 37-61 vol. %. Total olefins content in the gaseous product was 0.7-1.4 vol. %, proving the degree of feed olefins conversion. The ethane content was 0.3-1.2 vol. %, indicating suppression of side processes of ethylene hydrogenation by feedstock hydrogen.

TABLE-US-00001 TABLE 1 Composition of hydrocarbon fractions, wt % Hydrocarbon fraction, # A B C D E Description Mixture: 50 vol. % Straight- Straight- raffinate run run and Stable Light gas fraction fraction 50 vol. % natural conden- 65° C. - 85-180° fr. 62-85 gasoline sate e.b.p.** C.*** General hydrocarbon composition, PIONA*, wt % P (n-paraffins) 24.3 16.4 15.6 19.1 20.2 I (isoparaffins) 41.7 47.0 42.4 55.7 27.6 O (olefins) 1.8 1.1 1.1 1.6 1.7 N (naphthenes) 30.7 34.1 39.8 22.0 39.0 A (aromatics) 1.5 0.9 1.1 0.7 11.2 Unidentified — 0.5 0.0 0.9 0.3 Total, wt % 100.0 100.0 100.0 100.0 100.0 Detailed hydrocarbon composition, wt % C.sub.1-C.sub.4 0.0 0.0 0.0 0.0 0.1 hydrocarbons n-pentane 1.1 0.2 0.3 0.4 0.0 n-hexane 14.7 6.6 8.0 4.3 0.0 n-heptane 6.8 7.3 5.7 10.7 7.6 Normal C.sub.8+ 1.7 2.3 1.6 3.7 12.5 paraffins Isopentane 0.4 0.0 0.0 0.1 0.0 C.sub.6 isoparaffins 7.4 2.3 2.0 3.5 0.0 C.sub.7 isoparaffins 26.3 36.0 34.5 37.8 5.6 C.sub.8+ 7.6 8.7 5.9 14.3 22.0 isoparaffins C.sub.5+ olefins 1.8 1.1 1.1 1.6 1.7 Cyclopentanes 17.1 17.6 20.0 12.6 11.1 Cyclohexanes 13.6 16.5 19.8 9.4 27.9 Aromatics 1.5 0.9 1.1 0.7 11.2 Unidentified — 0.5 0.0 0.9 0.3 Total, wt % 100.0 100.0 100.0 100.0 100.0 incl. C.sub.6 46.1 36.4 43.4 23.4 1.2 hydrocarbons incl. benzene 1.2 0.7 0.9 0.4 0.0 *P (normal paraffins), I (isoparaffins), O (olefins), N (naphthenes), A (aromatics). Index is used for quick assessment of the fraction composition. **Straight-run gasoline, e.b.p.—end boiling point is not determined. ***Catalytic reforming feedstock. Characterized by low content of benzene-forming fraction (C.sub.6 hydrocarbons) and low content of C.sub.7 isoparaffins.

TABLE-US-00002 TABLE 2 Composition of olefin-containing fractions, wt % Olefin containing fraction, wt % A B C D Methane 0.0 4.8 38.5 21.7 Ethane 0.0 18.8 20.2 18.6 Ethylene 33.8 31.4 8.8 18.2 Propane 0.0 2.3 0.8 0.7 Propylene 0.0 13.5 0.7 3.5 Isobutane 0.0 3.5 0.8 0.7 n-butane 0.0 0.7 0.4 0.5 Sum of butylenes (butene-1, 0.0 5.1 0.5 2.3 butene-2, isobutylene, butadiene) Sum of C.sub.5+ hydrocarbons 0.0 4.2 0.2 3.0 H.sub.2 2.3 0.0 8.0 0.5 N.sub.2 63.9 15.0 19.5 28.2 Unidentified 0.0 0.7 1.6 2.1 Total: 100.0 100.0 100.0 100.0 incl. olefins 33.8 50.0 10.0 24.0 incl. C.sub.1-C.sub.2 hydrocarbons 33.8 55.0 67.5 58.5

TABLE-US-00003 TABLE 3 Composition of zeolite catalysts used in examples 1-12 Parameter Standard A B C Zeolite type — ZSM-5 ZSM-5 ZSM-5 Zeolite module, SiO.sub.2/ 43-95 77 43 95 Al.sub.2O.sub.3 mole ratio Composition of zeolite catalysts, wt % High silica zeolite of not less 70 65 80 pentasyl family than 65.0 Sodium oxide not more 0.08 0.15 0.04 than 0.15 Zinc oxide 1.0-5.5 2.0 1.0 5.5 Sum of oxides of rare 0.5-5.0 1.6 5.0 0.5 earth elements* Binder (SiO.sub.2 and/or Other, up Other, up Other, up Other, up Al.sub.2O.sub.3) to 100% to 100% to 100% to 100% including mass fraction 55.0-80.0 69 55 80 of silicon dioxide expressed as catalyst calcined at 550° C. *Rare earth elements (REE) include, specifically, lanthanum, praseodymium, neodymium, cerium, preferably their mixtures. Individual compounds of each element, such as nitrates, can be used as a source of rare earth element compounds. Mixtures of rare earth element compounds can also be a source of rare earth compounds. Specifically, semi-finished products of rare earth element production with mixed REE compounds content of at least 60 wt %, such as rare earth elements concentrate, rough REE concentrate, collective concentrates of rare earth metals, semi-finished products of rare earth ores processing, can be used as a source of rare earth element compounds. Mixtures of rare earth elements compounds can be used without preliminary separation of individual rare earth elements compounds.

TABLE-US-00004 TABLE 4 Conditions and main parameters in examples 1-7 Experiment number 7 1 2 3 4 5 6 (comparative) Hydrocarbon fraction B B C A D E B Oxygenate methanol methanol methanol DME ethanol methanol methanol Olefin-containing A B B D C A A fraction Catalyst A A B B C A A Weight hourly space 1.7 1.6 1.7 1.5 3.1 1.7 1.7 velocity, h.sup.−1 Total catalyst weight, 4713 4357 4357 4470 4316 4713 4713 grams Pressure, bar 22 27 22 15 40 27 5 Feed supply 350 350 340 370 350 340 350 temperature, 350 350 350 370 350 340 350 R.sub.101, R.sub.201, R.sub.301, ° C. 350 350 360 370 350 340 350 Percentage of 77.7 84.0 75.4 36.8 63.2 80.9 0.0 oxygenate substitution with olefin-containing fraction, % Hydrocarbon fraction, distribution over reaction zones, wt % R.sub.101* 100 100 100 100 100 100 100 R.sub.201 0 0 0 0 0 0 0 R.sub.301 0 0 0 0 0 0 0 Oxygenate, distribution over reaction zones, wt % R.sub.101 100 100 100 100 100 100 41 R.sub.201 0 0 0 0 0 0 37 R.sub.301 0 0 0 0 0 0 22 Olefin-containing fraction, distribution over reaction zones, wt % R.sub.101 30 22 20 25 30 20 none R.sub.201 30 33 20 20 20 35 R.sub.301 40 45 60 55 50 45 Catalyst, distribution over reaction zones, wt % R.sub.101 22 22 15 15 25 22 22 R.sub.201 33 33 35 35 30 33 33 R.sub.301 45 45 50 50 45 45 45 Feed composition, wt % Hydrocarbon 70.8 75.9 69.1 78.9 37.7 68.8 73.7 fraction, wt % Oxygenate, wt % 5.3 3.8 7.5 8.0 5.2 4.8 26.3 Olefin containing 23.9 20.3 23.4 13.1 57.1 26.4 0.0 fraction, wt % Total, wt % 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Main process parameters C.sub.5+ fraction 74.8 72.6 73.8 74.1 74.2 81.4 71.6 yield **, wt % C.sub.5+ product RON 90.6 92.4 90.8 91.6 90.5 90.4 88.1 *R.sub.101, R.sub.201, R.sub.301—first, second and third reaction zones. ** C.sub.5+ hydrocarbon yield per hydrocarbon fraction supplied.

TABLE-US-00005 TABLE 5 Composition of liquid hydrocarbon product free of dissolved gases (C.sub.5+ product) Example No. 7 1 2 3 4 5 6 (comparative) General hydrocarbon composition, PIONA*, wt % P (n-paraffins) 9.3 6.2 10.2 9.5 8.0 8.5 11.1 I (isoparaffins) 42.7 39.9 46.1 40.3 49.5 32.6 45.0 O (olefins) 1.2 0.7 2.1 3.8 1.9 5.7 1.3 N (naphthenes) 12.3 5.0 8.7 9.1 7.3 18.3 7.5 A (aromatics) 32.8 45.7 31.2 37.0 31.7 30.5 32.3 Unidentified 1.7 2.5 1.7 0.3 1.6 4.4 2.8 Total, wt % 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Detailed hydrocarbon composition, wt % C.sub.1-C.sub.4 hydrocarbons 0.0 0.0 0.0 0.0 0.0 0.0 0.0 n-pentane 5.1 4.5 5.3 6.6 5.8 4.5 5.6 n-hexane 3.1 1.4 3.8 1.7 1.6 2.0 3.5 n-heptane 0.8 0.2 0.7 0.2 0.3 0.8 0.9 Normal C.sub.8+ paraffins 0.3 0.1 0.4 1.0 0.3 1.2 1.1 Isopentane 6.9 8.8 6.3 11.1 9.5 5.1 6.9 C.sub.6 isoparaffins 7.0 7.1 7.1 8.9 9.8 4.5 8.8 C.sub.7 isoparaffins 24.4 17.6 27.5 14.8 21.0 5.6 22.6 C.sub.8+ isoparaffins 4.4 6.4 5.2 5.5 9.2 17.4 6.7 C.sub.5+ olefins 1.2 0.7 2.1 3.8 1.9 5.7 1.3 Cyclopentanes 9.8 4.1 4.8 7.7 6.5 7.5 3.7 Cyclohexanes 2.5 0.9 3.9 1.4 0.8 10.8 3.8 Aromatics 32.8 45.7 31.2 37.0 31.7 30.5 32.3 Unidentified 1.7 2.5 1.7 0.3 1.6 4.4 2.8 Total, wt % 100.0 100.0 100.0 100.0 100.0 100.0 100.0 incl. C.sub.6 hydrocarbons 19.0 14.6 17.8 17.0 17.8 9.0 20.6 incl. C.sub.7 isoparaffins 24.4 17.6 27.5 14.8 21.0 5.6 22.6 incl. naphthalenes and alkyl 0.9 0.7 0.9 0.1 1.0 0.1 1.1 naphthalenes incl. benzene 1.2 1.7 1.8 1.9 1.5 0.7 2.4 benzene ratio to total 3.7 3.7 5.8 5.1 4.7 2.3 7.4 aromatics, % n-hexane, conversion, wt % 64.6 84.9 64.5 91.6 72.5 none** 62.3 n-heptane, conversion, 89.8 98.1 89.0 97.3 97.3 90.1 88.7 wt % *P (normal paraffins), I (isoparaffins), O (olefins), N (naphthenes), A (aromatics) **Normal hexane is not present in the feedstock used in experiment No. 6.

TABLE-US-00006 TABLE 6 Conditions and main parameters of liquid hydrocarbon product free of dissolved gases (C.sub.5+ product) in examples Nos. 8-11*** Example No. 8 9 10 11 Hydrocarbon fraction B D C A Oxygenate methanol ethanol DME methanol Olefin-containing fraction A C D A Catalyst A B C A Weight hourly space velocity, 1.1 0.9 0.7 0.3 h.sup.−1 Total catalyst weight, grams 4713 4357 4316 4713 Pressure, bar 22 22 40 27 Feed supply temperature, ° C. R.sub.101 390 340 410 370 R.sub.201 390 340 420 370 R.sub.301 390 340 430 370 % of oxygenate substitution 80.5 63.2 36.8 77.7 with olefin-containing fraction Oxygenate, distribution over reaction zones, wt % R.sub.101 100 100 100 100 R.sub.201 0 0 0 0 R.sub.301 0 0 0 0 Olefin-containing fraction, distribution over reaction zones, wt % R.sub.101 30 20 10 25 R.sub.201 30 20 20 20 R.sub.301 40 60 70 55 Catalyst, distribution over reaction zones, wt % R.sub.101 22 15 25 22 R.sub.201 33 35 30 33 R.sub.301 45 50 45 45 Feed composition, wt % Hydrocarbon fraction, wt % 75.9 37.7 78.9 70.8 Oxygenate, wt % 3.8 5.2 8 5.3 Olefin containing fraction, 20.3 57.1 13.1 23.9 wt % Total, wt % 100.0 100.0 100.0 100.0 Main process parameters Liquid HC product yield, 63.4 66.9 66 57.2 wt %** Liquid product RON 97.7 97.2 97.5 98.4 Aromatics fraction, wt % 58.3 56.4 58.4 58.7 Benzene fraction, wt % 3.7 3.1 3.8 2.6 C.sub.8 aromatics fraction, wt % 18 17.4 17.5 16.6 C.sub.8 aromatics ratio to total 30.9 30.9 30 28.3 aromatics, % **C.sub.5+ hydrocarbon yield per hydrocarbon fraction supplied. ***In experiments 8-11, the whole hydrocarbon fraction is distributed to the first reaction zone

TABLE-US-00007 TABLE 7 Composition of stabilized liquid hydrocarbon product used in examples Nos. 1-7 Detailed hydrocarbon 7 composition, wt % 1 2 3 4 5 6 (comparative) C.sub.1-C.sub.4 hydrocarbons 3.6 4.2 3.5 3.8 4.8 4.5 4.8 n-pentane 4.9 4.3 5.1 6.3 5.5 4.3 5.3 n-hexane 3.0 1.3 3.7 1.6 1.5 1.9 3.3 n-heptane 0.8 0.2 0.7 0.2 0.3 0.8 0.9 Normal C.sub.8+ paraffins 0.3 0.1 0.4 1.0 0.3 1.1 1.0 Isopentane 6.7 8.4 6.1 10.7 9.0 4.9 6.6 C.sub.6 isoparaffins 6.7 6.8 6.9 8.6 9.3 4.3 8.4 C.sub.7 isoparaffins 23.5 16.9 26.5 14.2 20.0 5.3 21.5 C.sub.8+ isoparaffins 4.2 6.1 5.0 5.3 8.8 16.6 6.4 C.sub.5+ olefins 1.2 0.7 2.0 3.7 1.8 5.4 1.2 Cyclopentanes 9.4 3.9 4.6 7.4 6.2 7.2 3.5 Cyclohexanes 2.4 0.9 3.8 1.3 0.8 10.3 3.6 Aromatics 31.6 43.8 30.1 35.6 30.2 29.1 30.7 Unidentified 1.7 2.4 1.6 0.3 1.5 4.3 2.8 Total, wt % 100.0 100.0 100.0 100.0 100.0 100.0 100.0 incl. C.sub.6 hydrocarbons 18.3 14.0 17.2 16.4 16.9 8.6 19.6 incl. C.sub.7 isoparaffins 23.5 16.9 26.5 14.2 20.0 5.3 21.5 incl. naphthalenes and 0.9 0.7 0.9 0.1 1.0 0.1 1.0 alkyl naphthalenes incl. benzene 1.2 1.6 1.7 1.8 1.4 0.7 2.3 Product yield*, wt % 77.6 75.8 76.5 77.0 77.9 85.2 75.2 *Yield of stabilized liquid hydrocarbon product (stable gasoline after gaseous product separation) per hydrocarbon fraction supplied.

Observations

[0140] Reduction of Oxygenate Consumption

[0141] It has been found out that the task of reducing oxygenates consumption for production of gasoline or aromatic compound concentrates can be solved through partial substitution of oxygenates with low-demand olefin-containing fractions. This approach allows reducing oxygenates consumption while maintaining the yield and quality of the product.

[0142] Comparative example 7 shows that co-processing of hydrocarbon fraction and oxygenates (without involvement of olefin-containing fractions) allows to achieve C.sub.5+ hydrocarbon product fraction yield above 70% with product RON of about 88. Co-processing of hydrocarbon fractions and oxygenates (without involving olefin-containing fractions) often allows to obtain high-RON gasolines with high product yields. However, such oxygenates as methanol, ethanol, dimethyl ether are sparsely available at the refineries as a cheap feedstock. If no oxygenate source can be found as a component of by-product or semi-finished product of the refinery, it has to be purchased externally at marketable product prices. This shall increase the production cost per marketable gasoline unit and make the production logistics more complicated.

[0143] At the same time, the proposed method allows for partial substitution of oxygenates with a source of diluted olefins (olefin-containing fractions). In examples 1-6 and 8-12, the olefin-containing fractions act as partial substitute for feedstock oxygenates.

[0144] Percentage of oxygenates substituted with olefin-containing fractions is calculated according to formulas (4)-(6) in page 3 of this Description. The invention examples show that it is possible to substitute 37 to 84% oxygenate with olefin-containing fractions to obtain RON of liquid hydrocarbon product above 90.

[0145] The provided formulas (4)-(6) may apply to the known methods of co-processing hydrocarbon fractions and oxygenates (without involving olefin-containing fractions) into gasoline. In this case, formulas (4)-(6) allow to calculate the quantity (molar flow, mol/h) of oxygenate in the known method, which can be substituted with available olefin-containing fractions without impairment of quality and product yield.

[0146] Use of Low-Demand Hydrocarbon Fractions

[0147] According to Table 1, hydrocarbon fractions A-D used in examples 1-5 are characterized by high content of C.sub.6 hydrocarbons (benzene-forming fraction, 23-46 wt %) and C.sub.7 isoparaffins (26-38 wt %). Such hydrocarbon fractions may not be used as adequate feedstock for catalytic reforming processes or conventional isomerization. Specifically, processing of feedstock with high content of C.sub.6 hydrocarbons by known methods may result in a product with benzene content of 5 wt % and higher. At the same time, high content of C.sub.7 isoparaffins in the feedstock in the known processes may result in the product RON drop below 85. Presence of cycloparaffins in hydrocarbon fractions A-D also prevents their processing into high-octane gasoline components by conventional isomerization method.

[0148] Examples 1-4 demonstrate that the suggested method allows providing benzene content below 2.0 wt % even when using hydrocarbon fractions containing more than one third of benzene-forming fractions (C.sub.6 hydrocarbons content in hydrocarbon fractions A-C reaches 36-46 wt %). In this case, despite of high content of C.sub.7 hydrocarbons that are hard to process into high-octane components by the known methods, it is possible to achieve the product RON above 90.

[0149] Example 5 shows the case of processing hydrocarbon fraction E. This hydrocarbon fraction represents the feedstock suitable for catalytic reforming. Unlike hydrocarbon fractions A-D, this feedstock is characterized by low content of C.sub.6 hydrocarbons (1.2 wt %) and C.sub.7 isoparaffins (5.6 wt %). In this case, the proposed method allows to achieve target product yield above 80 wt % per feed supplied and benzene content in the product below 1 wt %.

[0150] Possibility to Use Olefin-Containing Fractions without Preliminary Separation of Hydrogen

[0151] It has been found out that the proposed method allows using olefin-containing fractions with increased hydrogen content as a feedstock. At the same time, the proposed method does not require additional separation of hydrogen from the olefin-containing fraction.

[0152] Specifically, examples 1, 4-6 and 8-12 use olefin-containing fractions with hydrogen content of 0.5 to 8 wt %. In the given case, the olefin-containing fractions were supplied to the reaction zones without hydrogen pre-separation from them.

[0153] This result is important because fuel gases often contain olefins simultaneously with noticeable amounts of hydrogen. But the presence of hydrogen in the olefin source may lead to side reactions.

[0154] Specifically, during preliminary studies outside the recommended range of conditions, it was observed that inclusion of 0.5 to 8 wt % of hydrogen in the olefin-containing fractions would reduce the liquid hydrocarbon product yield by 3-6 wt % (while maintaining the same molar flow of olefins and feed supply rate). Besides, when hydrogen content in the olefin-containing fractions was 2.3 to 8 wt %, a decrease in high-octane alkyl benzenes portion in the product by 0.6-2.3 wt % was observed. Such results could be observed due to side process of feedstock olefins hydrogenation.

[0155] The proposed method application made it possible to suppress such negative effects, also by means of oxygenate feeding in the first reaction zone, while simultaneously feeding olefin-containing fractions into three reaction zones. At the same time, the portion of the olefin containing fraction delivered to the third reaction zone is greater than the portion of the olefin-containing fraction distributed to the first or second reaction zones.

[0156] Invention examples 1, 4-6 and 8-12 show no decrease in the yield of liquid hydrocarbon product or decrease in the alkyl benzene content of the product due to hydrogen inclusion in the olefin-containing feedstock fractions.

[0157] This widens the possibilities of the method in the involvement of low-value sources of C.sub.2-C.sub.4 olefins in production of gasolines or aromatic compound concentrates.

[0158] Possibility to Use Olefin-Containing Fractions without Preliminary Increasing the Olefins Concentration

[0159] The possibility of using low-demand olefin-containing fractions as a feedstock for production of gasoline or aromatic compound concentrates was also considered. Refineries produce olefin-containing fractions used as fuel. These are catalytic cracking gases, gases from delayed coker unit, olefin-containing fuel gases of different origin, etc. The content and composition of olefins in such streams is too low for commercially viable recovery. At the same time, the price of streams burned as fuel is minimal. Involvement of such olefin-containing fractions in production of gasoline or aromatic concentrates significantly increases the stream value for a company.

[0160] Examples 1-6 and 8-12 demonstrate the possibility of using olefin-containing fractions with olefin content below 50 wt %. Specifically, it is possible to use gaseous sources of olefins with olefin content of 10 wt % (or higher). This allows reducing significantly the unit production costs as compared to methods where highly concentrated olefin sources or chemically pure olefins are used.

[0161] The proposed method allows to use diluted olefins instead of highly concentrated sources of olefins (e.g. pure ethylene). This allows using semi-finished products and by-products of existing petrochemical production facilities as a source of olefins. Among them are dry gases of catalytic cracking, various fuel gases with olefin content from 10 to 50 wt %.

[0162] Oxygenate-Free Liquid Hydrocarbon Product

[0163] The proposed method allows to obtain liquid hydrocarbon product free of oxygenates. Oxygenates, specifically ethanol, are often used as octane-increasing additives in compounding of motor gasoline. However, the maximum content of oxygenates in commercial gasoline is strictly regulated. Liquid hydrocarbon products obtained in examples 1-6 and 8-12 do not contain oxygenates, but have a high octane number according to the research method (product RON above 90). Such combination of properties allows using maximum permissible amount of oxygenates when compounding commercial gasoline based on the product obtained by the proposed method.

[0164] Possibility to Avoid Gaseous Products Recycling

[0165] The proposed method is found to skip the gaseous products recycling. All the proposed method application examples show a conversion rate for feedstock C.sub.2-C.sub.4 olefins higher than 98 wt %. Such high degree of conversion in one pass through the reactor allows avoiding gaseous product recycling for the purpose of deeper processing of feedstock olefins.

[0166] Reduction of Benzene Portion in Liquid Hydrocarbon Product

[0167] It is found that, while producing gasolines, the proposed method provides for reduction of the benzene portion in liquid hydrocarbon product to 0.7-1.9 wt %. At the same time, the ratio of benzene to the sum of aromatic hydrocarbons is reduced to 2.2-5.8 wt %. This is achieved even when C.sub.6 hydrocarbons make up more than one third of the feedstock hydrocarbon fraction composition. Specifically, the used hydrocarbon fractions A-C contained from 36 to 46 wt % of C.sub.6 hydrocarbons. The C.sub.6 hydrocarbons are benzene precursors in the known catalytic processes of gasoline production. Conversion of hydrocarbon fraction with high benzene precursors content by the known methods would result in a product with high benzene content. It is difficult to use such product in motor gasoline compounding, where maximum benzene content is strictly limited. Specifically, catalytic reforming of hydrocarbon fraction containing 36-46 wt % of C.sub.6 hydrocarbons would result in a product with benzene content more than 5-10 wt %, which is much higher than the result obtained by the proposed method.

[0168] Enhancement of n-Hexane and n-Heptane Conversion

[0169] Despite high content of C.sub.6 hydrocarbons and use of cheaper feedstock (oxygenate part substitution with olefin-containing gases) the proposed method allows to enhance n-hexane and n-heptane conversion.

[0170] Specifically, n-hexane conversion reaches 91.6 wt % and n-heptane conversion—97.3 wt %.

[0171] Reduction of Naphthalenes and Alkylnaphthalenes Content

[0172] At the same time, content of naphthalenes and alkylnaphthalenes in liquid hydrocarbon product is maintained or reduced. Specifically, naphthalenes and alkylnaphthalenes content is achieved at the level of 0.1 wt % in example 4. Naphthalenes and alkylnaphthalenes are undesirable components in commercial gasoline, particularly because of their high boiling points and tendency to crystallize.

[0173] Possibility to Produce Low-Benzene Aromatics Concentrates

[0174] In process of obtaining aromatic compound concentrates, it is also possible to produce low-benzene aromatics concentrates. There are known several conventional methods for production of AHF (aromatic hydrocarbon fractions, or aromatic hydrocarbons concentrate). The aromatics concentrates may be obtained, e.g., in process of catalytic reforming, or as oil refining by-products. The produced aromatics concentrates may be used as high-octane base in motor gasoline compounding. Unfortunately, the known methods often result in aromatics concentrate production with extremely high benzene content (benzene content in liquid hydrocarbon product of more than 15 wt %). The high benzene content in aromatics concentrate drastically limits its use in blending motor gasolines, since maximum benzene content in fuels is strictly controlled.

[0175] However, the proposed method of obtaining aromatic compound concentrates allows producing low-benzene AHF (aromatics fractions). The liquid hydrocarbon product obtained in examples 8-11 contains 56-66 wt % of aromatic hydrocarbons with the benzene content of 3-4 wt %. Hence, the proposed method allows obtaining AHF with significantly lower benzene content as compared to conventional methods.

[0176] Possibility to Produce Aromatics Concentrate with High C.sub.8 Alkylbenzenes Content

[0177] In process of obtaining aromatic compound concentrates, it is also possible to produce aromatics concentrates with higher content of C.sub.8 alkylbenzenes. Examples 8-11 demonstrate that the proposed method allows to achieve C.sub.8 alkylbenzenes content in liquid hydrocarbon product of 17-18 wt %. At the same time, the portion of C.sub.8 aromatics relative to the total aromatics reaches 28-31 wt %. Average RON of C.sub.8 alkylbenzenes reaches 112, which makes them the attractive components for compounding high-octane gasolines.

[0178] Distributed Feed of Hydrocarbon Fraction

[0179] It has been observed that change in hydrocarbon fraction supply to the reaction zones allows to control several process parameters. Specifically, distribution of hydrocarbon fraction in two or three reaction zones allows to additionally increase the yield and/or formation selectivity of C.sub.5+ hydrocarbons (hydrocarbons with five or more carbon atoms). Besides, in case of distributed feed of hydrocarbon fraction in several reaction zones, cracking of isoparaffins with two or more alkyl substituents with formation of lower C.sub.1-C.sub.4 hydrocarbons can be suppressed. The hydrocarbon fraction distribution into multiple reaction zones may also result in reduced dealkylation of alkylaromatic hydrocarbons.

[0180] Specifically, example 12 shows the possibility of distributing hydrocarbon fraction into multiple reaction zones. Example 12 repeats the conditions of example 1, except for changes in the hydrocarbon fraction distribution. In example 1, the hydrocarbon fraction distribution into reaction zones R.sub.101/R.sub.201/R.sub.301 was 100/0/0 wt %. Example 12 maintains the same feed mass rates as example 1, but the hydrocarbon fraction is distributed over the three reaction zones in the ratio of 50/25/25 wt %. As a result, the product yield is increased by 3 wt % per hydrocarbon fraction supplied (from 74.8 to 77.7 wt % for liquid hydrocarbon product free of dissolved gases).

[0181] In example 12, the aromatics content in the product (liquid hydrocarbon product free of dissolved C.sub.1-C.sub.4 gases) is reduced by 3.2 wt % as compared to example 1 (from 32.8 to 29.6 wt %). Normally, a decrease in the product octane number is expected when aromatics concentration in the product reduces. However, it was found out that the product RON in example 12 was virtually the same as the one of the product in example 1 (90.6 and 90.8, respectively). This effect can be explained by cracking reduction of high-octane C.sub.5-C.sub.8 isoparaffins (isoparaffins with individual octane numbers according to the research method above 72) as a result of distributed hydrocarbon fraction supply to several reaction zones.

[0182] It is also possible to distribute the whole hydrocarbon fraction stream only to the second or only to the third reaction zone, if necessary.