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USEFUL ADDITIVES FOR PETROL AND OTHER MOTOR FUELS
INVENTION
Patent of the Russian Federation RU2206601

METHOD OF HYDROBANDING OF THE PETROL FINE OF CATALYTIC CRACKING

METHOD OF HYDROBANDING OF THE PETROL FINE OF CATALYTIC CRACKING

The name of the inventor: Durik NM; Kotov SA; Zayashnikov E.N .; Zotkin VA; Knyazkov AL; N. Lagutenko; Nikitin AA; Esipko EA; Kirillov D.V.
The name of the patent holder: Open Joint-Stock Company Slavneft-Yaroslavnefteorgsintez
Address for correspondence: 150000, Yaroslavl, Slavneft-Yaroslavnefteorgsintez JSC, technical department, head of the department V.V. Kopanskov
Date of commencement of the patent: 2001.08.30

Use: petrochemistry. Essence: gasoline fraction by rectification is divided into 3 fractions: easy-boiling n.c. - 60-70 o C, medium-boiling 60-70-150-160 o C and heavy 150-160-c.k. The heavy gasoline fraction is subjected to hydrodesulfurization followed by its mixing with non-hydrotreated light-boiling and medium-boiling gasoline fractions. Hydrodesulfurization is carried out in the presence of an oxide-sulphide catalyst at elevated temperature and pressure of a hydrogen-containing gas. The technical result: reduction of sulfur content in gasoline fractions of catalytic cracking without reducing the content of olefinic hydrocarbons in them and reducing the octane number.

DESCRIPTION OF THE INVENTION

The invention relates to chemical technology, in particular to methods for hydrotreating gasoline fractions, and can be used in the petroleum refining and petrochemical industries.

Catalytic cracking fuels (CKF), which are one of the main multi-tonnage components of gasoline and determine the consumer properties of the latter, are characterized by a high content of aromatic (20-30% and more) and olefinic (16-40%) hydrocarbons. In cases where non-hydrotreated feedstocks are processed in catalytic cracking plants, the high content of sulfur compounds in the resulting gasoline fractions (0.25-0.35% by weight and more) makes it difficult to use them for the preparation of marketable gasolines.

The process of hydrotreatment of gasoline fractions of KKF is technologically more complex in comparison with hydrotreatment of straight-run gasoline fractions, since it should not undergo hydrogenation reactions of olefinic hydrocarbons with simultaneous maximum removal of sulfur compounds. One of the most important factors determining the efficiency of this process is the fractional composition of the raw materials. By subjecting the organosulfur compounds to purification, only the high-boiling portion of the CKF gasoline fraction that does not contain olefinic hydrocarbons significantly increases the desulfurization depth, since hydrotreating can be carried out under more stringent conditions. In this case, due to the small content of unsaturated hydrocarbons, there is a slight temperature drop at the inlet and outlet of the reactor and there is no drop in the value of the octane number (OC).

There are known methods of hydrobesselation of gasoline fractions of CCl [US Patent 5,391,288, Cl. C 10 G 45/00, 69/00; Aladysheva EZ, Peregudova VA, Strom LD, Khuramshin RT-Chemistry and Technology of Fuels and Oils, 1988, 3, pp. 34-35; US Patent 5,397,455, Cl. C 10 G 45/02, 69/02], according to which the CKF gas fractions containing sulfur and olefins are hydrodesulfurized at elevated temperature and pressure in the presence of a catalyst containing metals of groups 8 and 6 of the batch system on an aluminum-aluminum support to obtain Product with reduced sulfur content.

A disadvantage of the known methods is a decrease in the amount of OC gasoline KKF after hydrodesulfurization.

It is known [US Pat. No. 5,318,690, cl. C 10 G 35/00, 45/00, 208-89], a method for upgrading the gasoline fraction of the CKF boiling at a temperature above 162 ° C by first fractionating the wide gasoline fraction of the CCl into a low boiling point and a high boiling point fraction. Further, the high-boiling gasoline fraction is subjected to catalytic hydrodesulfurization in the presence of hydrogen at elevated temperature and pressure.

A disadvantage of the known method is the low value of the product of the product, which forces it to be further processed with an acid catalyst in order to increase the end product oxidation and secondary hydrodesulfurization to produce a desulfurized product with boiling range of gasoline.

Known [EPO application 940464, cl. C 10 G 65/00, publ. 8.09.99], a method for reducing the sulfur content by separating gasoline KKF into a light fraction of 50-80% of the product, a medium-boiling fraction of 10-30% of the product, and a heavy fraction of 5-20% of the product. The heavy fraction is hydrodesulfurized until completely removed. The product is mixed with the medium-boiling fraction and again subjected to hydroprocessing.

A disadvantage of the known method is the need to purify gasoline in 2 stages, which complicates the technological scheme of obtaining gasoline KKF with a reduced sulfur content.

The closest solution to the technical essence and the results achieved is the method for cleaning gasoline KKF [patent RF 2134287, cl. С 10 G 55/06, publ. 10.08.1999], according to which the hydrobessulfurization in the presence of an oxide-sulfide catalyst at elevated temperature and pressure of a hydrogen-containing gas is subjected to a heavy unstable gasoline fraction of the PCF withdrawn as the upper circulation irrigation from the rectifying column of the PCF unit, followed by its return after hydrodesulfurization to this The rectification column and stabilization together with the non-hydrotreated light gasoline fraction.

The disadvantage of the method adopted for the prototype is a relatively low depth of sulfur removal from gasoline KKF, tk. The fraction subjected to hydrodesulfurization has a higher boiling point temperature and contains 30-50% kerosene fraction which need not be hydrodesulfurized.

The object of the present invention is to reduce the sulfur content of the gasoline fractions of the PCC without reducing the olefinic hydrocarbon content therein and to reduce the amount of OCH.

The aim is achieved by the hydrodesulfurization of the gasoline fraction of the CCl in the presence of an oxide-sulphide catalyst at elevated temperature and pressure of the hydrogen-containing gas, according to which the gasoline fraction of the CKF is separated by rectification into 3 fractions: a low-boiling nc- 60-70 ° C, a medium-boiling 60-70- 150-160 ° C and heavy 150-160 ° C - The heavy gasoline fraction is subjected to hydrodesulfurization followed by its mixing with non-hydrotreated light-boiling and medium-boiling gasoline fractions.

An essential distinctive feature of the proposed method is that the gasoline fraction of the CKF is separated by rectification into 3 fractions: a low-boiling NO - 60-70 o C, medium-boiling 60-70-150-160 o C and heavy 150-160 o C-C, the heavy gasoline fraction is hydrodesulfurized, followed by mixing it with non-hydrotreated low-boiling and medium-boiling gasoline fractions.

Thus, the claimed method corresponds to the criterion of the invention "novelty".

Analysis of the known technical solutions for the methods for cleaning gasoline fractions of the FCC allows us to conclude that there are no signs in them that are similar to the essential distinctive features of the claimed method, that is, the conformity of the claimed method with the requirements of the inventive level.

The essence of the proposed method is the following (see the drawing). The distillate of vacuum distillation of fuel oil that has not undergone preliminary hydrotreating is subjected to catalytic cracking in the presence of a microspheroidal zeolite-containing catalyst. On the main fractionation column K-1 of the fractionating unit of the KKF unit, the cracking products are separated into a wide gasoline fraction of n.c. - 205-215 o C (sulfur content before the hydrodesulfurization unit is turned on: 0.22-0.30% by weight, with an RPM of 80.6-80.9 points) and gas oil fractions.

METHOD OF HYDROBANDING OF THE PETROL FINE OF CATALYTIC CRACKING

The wide gasoline fraction is sent for fractionation to the rectifying column K-2 with a conclusion of 3 fractions: a low-boiling (nc - 60-70 o C), medium boiling (60-70-150 ° C) and heavy (150-160 o C - ks). The yields of the fractions are 15-20, 60-65 and 20-25% by weight, respectively. Working conditions of the column: top temperature 88-90 o C; Bottom 224-229 ° C; Top pressure 2.8-3.0 atm; Bottom 3.1-3.3 ati.

A heavy gasoline fraction (sulfur content 0.55-0.70% by weight) is hydrodesulfurized in the presence of an oxide-sulphide catalyst at a pressure of 2.8-4.5 MPa and a space velocity of 3-5 h -1 . Hydrogenisate in the stripping column K-3 undergoes stabilization at a top temperature of 85-90 ° C, a bottom of 105-110 ° C, a pressure of 1.2-1.4 at.

After mixing the hydrotreated heavy gasoline fraction with the low-boiling and medium-boiling fractions of gasoline, the KKF produces a stable gasoline fraction with a sulfur content of 0.07-0.09% by weight, while the amount of OCH retained.

The advantages of the proposed method are illustrated by the examples below.

Example 1

Distillate of vacuum distillation of fuel oil. 350-540 ° C, obtained from a mixture of West Siberian, Tatar and Bashkir oils and not pre-hydrotreated (sulfur content 1.66% by weight, fractional composition: up to 360 ° C boils out 5%, 95% - 538 ° C), subjected Catalytic cracking at a reactor temperature of 520 ° C in the presence of a microsphere zeolite-containing Futura-120 GSR catalyst. On the main fractionation column K-1 of the fractionating unit of the KKF unit, the cracking products are separated into a wide gasoline fraction of n.c. - 215 ° C (sulfur content 0.30% by weight, mp 80.6 ppm, density 730 kg / m 3 , iodine value 80 g / 100 g) and gas oil fractions.

The wide gasoline fraction n. To-215 ° C (yield 50.3% by weight of the feed) is sent to fractionation in a K2 distillation column with a conclusion of 3 fractions: a low-boiling (at 60 ° C), medium boiling (60-150 ° C ) And heavy (150 o C - c.). The yields of the fractions are 17, 58 and 25% by weight, respectively. Working conditions of the column: top temperature 88 o C, bottom 224 o C, top pressure 3.0 ati, bottom 3.3 ati.

A heavy gasoline fraction (sulfur content 0.55 mass%, density 845 kg / m 3 , iodine number 28 g / 100 g) is hydrodesulfurized in the presence of a Grace 465 alumina-cobalt-molybdenum catalyst (content, wt.%: Molybdenum oxide-18.5, Cobalt oxide - 4.5, aluminum oxide - the rest up to 100%). The mixture of raw materials and hydrogen-containing gas (WASH) is heated in a heat exchanger and furnace, from where the gas-raw mixture heated to a temperature of 250 ° C is fed to the reactor, where at a pressure of 4.5 MPa and a space velocity of 3 h -1, hydrogenation purification of raw materials from sulfur-containing compounds occurs .

From the reactor, the gas product mixture is sent to a heat exchanger where, through heat exchange with the gas-raw mixture, it is cooled in the refrigerator and enters the separator to separate the gas product mixture into a WASH and unstable hydrogenate.

The unstable hydrogenate from the separator passes through the tube space of the heat exchanger and is sent to the stripping column K-3, where degassing of the hydrogenate with partial removal of moisture, hydrocarbon gases and hydrogen sulphide occurs. The operating conditions of the stripping column are: top temperature 85 ° C, bottom 105 ° C, pressure 1.2 at.

After mixing the hydrotreated heavy gasoline fraction with the low-boiling and medium-boiling fractions of the gasoline, the FCC produces a stable gasoline fraction with a sulfur content of 0.07 wt.% Sulfur, with a retained value of rm m. (80.3 points).

Example 2

On the main rectification column K-1 of the fractionating unit of the FCC unit, the cracking products obtained according to Example 1 are separated into a wide gasoline fraction of n.c. - 205 ° C (sulfur content 0.22% by weight, m.p. m. M. 80.9 points, density 725 kg / m 3 , iodine number 90 g / 100 g) and gas oil fractions.

The wide gasoline fraction n. To -202-215 ° C (49.8% yield for raw materials) is directed to fractionation in a K-2 rectification column with a conclusion of 3 fractions: a low-boiling (at 70 ° C), medium boiling (70-160 ° C ) And heavy (160 o C - c.). The yields of the fractions are 19, 61 and 20% by weight, respectively. Working conditions of the column: top temperature 90 o C, bottom 229 o C, top pressure 2.8 ati, bottom 3.1 ati.

A heavy gasoline fraction (sulfur content 0.70 mass%, density 850 kg / m 3 , iodine value 17 g / 100 g) was hydrodesulfurized according to Example 1 at a temperature of 330 ° C, a pressure of 2.8 MPa and a space velocity of 5 h - 1 . The operating conditions of the stripping column are: top temperature 90 ° C, bottom 110 ° C, pressure 1.4 at.

After mixing the hydrotreated heavy gasoline fraction with the low-boiling and medium-boiling fractions of gasoline, a stable gasoline fraction with a sulfur content of 0.09 wt.% Sulfur is stored at a stored value of rm m.p. (80.6 points).

Example 3 (prototype)

On the main rectifying column K-1 of the fractionating unit of the KKF unit, the cracking products according to Example 1 are separated into a wide gasoline fraction n. To-215 ° C (sulfur content 0.26% by weight prior to the inclusion of the hydrotreating unit, an MP of 80.7 ppm) and gas oil fractions. To regulate the temperature of the distillation column, four circulation irrigation are used on the plates. The first circulating irrigation is heavy gasoline (ff 110-240 o C, sulfur content 0.65 mass%, iodine number 5.1 g / 100 g, bp meter 74.3 points) with 24 plates pump through Air cooling apparatus and served on a 26 plate.

The balance quantity of heavy gasoline from the pump discharge of the first circulating reflux pump is withdrawn to the direct feed tank of the hydrotreatment unit, from where it passes through the filters to receive the feed pumps of the hydrotreatment unit and is supplied for mixing with the WASH.

The mixture of gasoline and WASH is heated in a heat exchanger and a furnace, from where the gas mixture heated to a temperature of 250 ° C. is fed to the reactor, where in the presence of a Grace catalyst 465 (content, wt.%: Molybdenum oxide 18.5, cobalt oxide 4, 5, aluminum oxide - the rest to 100%) at a pressure of 3 MPa, hydrogenation purification from sulfur-containing compounds occurs. From the reactor, the gas mixture is sent to the heat exchanger, where, by heat exchange with the gas-base mixture, it is cooled in a refrigerator to a temperature of 45 ° C and fed to a separator to separate the gas product mixture into a FGS and unstable hydrogenate.

The unstable hydrogenate from the separator passes through the tube space of the heat exchanger and is sent to the stripping column, where at a pressure of 0.8 atm and a bottom temperature of 185 ° C, hydrogenation is stabilized.

The hydrotreated heavy gasoline fraction (sulfur content 0.09 mass%, iodine number 2.5 g / 100 g) is cooled from the stripping column to a temperature of 45 ° C and returned to the pump of the upper circulation reflux of the rectification column of the KKF unit. The wide gasoline fraction emitted on this column is an unstable mixture of a non-hydrotreated light gasoline fraction of nickel. 110.degree . C. and a hydrotreated heavy gasoline fraction of 110.degree . C. to a reflux condensate, after stabilization, it contains 0.13 wt.% Sulfur and has an O.O. m. M. Of 79.8 points.

Thus, during the hydrotreatment of the heavy gasoline fraction of the CFC obtained by distilling off the low-boiling gasoline fractions from the gasoline of the PCF, a stable gasoline with a reduced sulfur content (0.07-0.09% by weight) is obtained after mixing without decreasing the value of the RPM. (80.3-80.6 points) (examples 1 and 2). The implementation of the method according to the prior art (Example 3) is less effective (sulfur content of 0.13% by weight, OH mp 79.8 points, due to the fact that the fraction subjected to hydrodesulfurization contains, in addition to gasoline, more than 30% by weight Kerosene fraction.

CLAIM

A method for hydrodesulfurizing a gasoline fraction of catalytic cracking in the presence of an oxide-sulphide catalyst at elevated temperature and pressure of a hydrogen-containing gas, characterized in that the gasoline fraction is divided into three fractions by rectification: - 60-70 o C, medium-boiling 60-70-150-160 o C and heavy 150-160-cc, the heavy gasoline fraction is hydrodesulfurized, followed by mixing it with non-hydrotreated low-boiling and medium-boiling gasoline fractions.

print version
Date of publication 07.04.2007gg