RU2010838C1 - Method of recovery of high antiknock gasoline and aromatic hydrocarbons - Google Patents

Abstract

FIELD: petrochemistry. SUBSTANCE: wide and narrow fractions containing predominantly C₇-C₁₀ and C₆-C₇ hydrocarbons, respectively, are subjected separately to catalytic reforming. Intermediate benzene-containing fraction containing 2-50% isohexanes out of the potential in liquid reformat, is isolated from liquid reformats. Then it is co-treated along with narrow fraction reforming gas product in the presence of catalyst containing pentasil zeolites and at a (3-20): 1 mass ratio, under narrow fraction reforming pressure and 270-380 C. Low-molecular aromatic hydrocarbons are isolated from co-treatment products through extraction or extractive rectification. The remainder of co-treated products, after benzene-containing fraction has been isolated, are directed totally or partially to mixing with liquid reformats. Benzene-containing fraction contains 1-25% toluene of its potential in wide fraction liquid reformat. EFFECT: recovery of high antiknock gasoline and aromatic hydrocarbons improved. 2 cl, 2 tbl

Description

 The invention relates to oil refining, and more specifically to methods for producing high-octane gasoline, and aromatic hydrocarbons based on reforming catalysts of wide fractions.

For the production of high octane gasoline reforming catalysts subjected to platinasoderzhaschih wide gasoline fractions boiling in the range of 60-90 ^{° C} (initial boiling point) to 160-180 ^{° C} (boiling end). Such raw materials contain C ₆ -C ₁₀ hydrocarbons, mainly (not less than 70%) C ₇ -C ₁₀ .

Reforming is carried out at 460-550 ^about With and a pressure of up to 4 MPa. The liquid reforming products after cooling and operation are separated from the circulating reforming gas, subjected to stabilization (debutanization). Stable catalysis is obtained as high-octane gasoline or its component (1-3). The reforming catalysts of gasoline fractions contain non-aromatic and aromatic hydrocarbons, including some benzene, depending on the hydrocarbon composition of the feed and the reforming mode, the benzene content can be in the range of 1-8%.

 Benzene degrades the environmental performance of gasoline, but at the same time it is a valuable product for the industry of organic synthesis and the production of synthetic materials.

For the benzene and other aromatic hydrocarbons narrow reforming gasoline fractions, such as 62-105 ^{° C,} to produce benzene, toluene, or 62-140 ^{° C} to produce benzene, toluene, xylenes. Common is the use of raw materials containing predominantly C ₆ -C ₇ hydrocarbons (at least 70%). Aromatic hydrocarbons are isolated from reforming catalysts by extraction or extractive distillation, while the non-aromatized portion remains - raffinate. Raffinate has low octane characteristics and is used for the production of low-octane gasolines and as solvents (2-3).

 In industry, the majority of gasoline fractions are used to produce motor gasolines; therefore, the capacity of plants for raw materials for gasoline production is significantly (2-3 times) higher than for the production of aromatic hydrocarbons. The main objectives of reforming gasoline production are to increase the octane number and reduce the content of aromatic hydrocarbons and especially benzene. Known methods for increasing the octane number of reforming catalysts using selective hydrocracking, the implementation on catalysts whose cracking base is geometrically selective zeolites, such as chabazite, gmelinite, pentasil, erionite (4-6), lead to an undesirable increase in the content of aromatic hydrocarbons and, in particular including benzene.

The closest in technical essence to the present invention is a method for producing motor gasoline and aromatic hydrocarbons, comprising reforming a wide (62-180 ^о С) gasoline fraction, isolating from liquid reforming products by distillation of benzene (60-95 ^о С), benzene-toluene (60- 120 ° ^C) for a benzene-toluene-xylene (60-150 ° ^C) fractions, sending them to the extraction or extractive distillation to separate aromatics and mixing with the remaining portion unscented products Riforma nga. (7 prototype).

However, the removal of aromatic hydrocarbons leads to a decrease in the octane number of gasoline. In the case where the mixed catalysate without benzene fraction (60-95 ° ^C) with this raffinate fraction octane number decreases relatively little 0.6 n., But reduction of aromatics slightly, only 1.2%. In other cases, when it is possible to significantly reduce the content of aromatic hydrocarbons, the octane number of gasoline sharply decreases. Thus, the disadvantage of this method lies in its low efficiency, the removal of benzene from reforming catalysis and its preparation as one of the products leads only to a slight decrease in the content of aromatic hydrocarbons and then with a decrease in the octane number. Therefore, it is necessary to introduce expensive alkylate or other fractions of gasoline into gasoline.

 The proposed method provides for the production of gasolines with a low content of aromatic hydrocarbons in the practical absence of benzene without a significant decrease or increase from the octane number. At the same time, the output of the most valuable aromatic hydrocarbons increases.

A method for producing high-octane gasoline and aromatic hydrocarbons is proposed, according to which separately wide and narrow gasoline fractions are subjected to catalytic reforming, containing mainly C ₇ -C ₁₀ and C ₆ -C ₇ hydrocarbons, respectively, an intermediate benzene-containing fraction extracted from liquid reforming products of a wide fraction containing 2-50% of isohexanes from the potential in the liquid reforming product is processed together with the gas product stream leaving the reforming zone th fraction in the presence of a catalyst comprising the pentasil and Y zeolite in a weight ratio of 3-20 to 1 for a pressure reforming narrow fraction and a temperature ^of 270-380 C is isolated by extraction or extractive distillation of low molecular weight aromatic hydrocarbons from co-processing products, the rest of the liquid product or completely partially mixed with other liquid reforming products. The isolated benzene-containing fraction contains 1-25% of toluene from its potential in the liquid product of reforming a wide fraction.

Comparative analysis with the prototype allows us to conclude that the inventive method differs from the known one in that the catalytic reforming is subjected to separately wide and narrow fractions containing predominantly C ₇ -C ₁₀ and C ₆ -C ₇ hydrocarbons, respectively; benzene-containing contains 2-50% of isohexanes of potential in the liquid reforming product; the benzene-containing fraction is processed together with the gas product stream leaving the reforming zone of the narrow fraction in the presence of a catalyst containing pentasil and Y in a mass ratio of 3-20 to 1; joint processing is carried out at a temperature of 270-380 ^about With and the pressure of reforming a narrow fraction; for mixing with the remaining liquid reforming products of a wide fraction, a part or all of the liquid product of joint processing is sent after separation of low molecular weight and aromatic hydrocarbons from it.

 A preferred feature of the invention is the content in the benzene-containing fraction of 1-25% of toluene from its potential in the liquid product of the reforming of a wide fraction.

 Thus, the claimed method meets the criteria of the invention of "novelty."

 The proposed method is as follows.

Straight-wide gasoline fraction containing mainly hydrocarbons C ₇ -C _10, after the hydrotreatment was subjected to catalytic reforming in the presence of catalysts aljumoplatinovyh (with or without promoters) under known conditions at a temperature of 480-530 ^C and pressures up to 4 MPa. A hydrotreated narrow gasoline fraction is predominantly subjected to catalytic reforming, containing predominantly C ₆ -C ₇ hydrocarbons under a pressure below 2 MPa and other conditions mentioned above. The installation is equipped with an additional reactor through which the gas-product mixture passes together with a recycle hydrogen-containing gas.

 An intermediate benzene-containing fraction is separated from the catalytic reforming of a wide fraction by distillation on two successively connected distillation columns.

However, it is possible to confine ourselves to one additional distillation column if the first stage of distillation is carried out in the debutanization column of unstable catalytic reforming of a wide fraction and withdrawal of a C ₅ -C ₇ hydrocarbon fraction from it, which is sent to an additional column, the target benzene-containing fraction is removed from the cube, and on top fraction of lighter hydrocarbons. The method of isolating the benzene-containing fraction is not the subject of the invention, because it can be calculated on a computer.

 However, the compositional requirements of the benzene-containing fraction, expressed in the range of permissible amounts of isohexane from the potential in the liquid reforming product, is an important feature of the invention. This fraction preferably also contains toluene in the amount indicated above.

, образованные 10-членными кольцами из атомов кислорода, Y имеет окна диаметром около 10

, образованные 12-членными кольцами из атомов кислорода (8).The specified fraction is sent to an additional reactor, where it is processed together with the gas product stream in the gas phase on a catalyst containing synthetic zeolites pentasil and Y in a ratio of 3-20 to 1. Pentasil is a high-modulus zeolite with pores with a diameter of about 5.6

formed by 10-membered rings of oxygen atoms, Y has windows with a diameter of about 10

formed by 12-membered rings of oxygen atoms (8).

 Catalysts based on these zeolites typically contain a hydrogenation group 6 and / or 8 metal, for example, molybdenum, palladium, platinum. The quantitative and even qualitative composition of the catalyst is not an essential feature of the invention; it is only important that the ratio of pentasil and Y zeolites be in the range of 3-20 to 1, and their total content should be at least 20%.

 Process conditions should be selected so as to prevent hydrogenation of aromatic hydrocarbons.

Joint processing temperature in the range ^of 270-380 C. The process pressure determined by the pressure reforming narrow fraction, typically below 2 MPa. The low molecular weight hydrocarbons extracted by extraction are benzene, and toluene, if necessary, C ₈ aromatic hydrocarbons are also obtained.

 The rest of the liquid co-processing liquid products, which are raffinate, higher aromatic hydrocarbons, are combined with the liquid product of reforming a wide fraction from which the benzene-containing fraction has been previously removed.

 Thus, the proposed method allows to obtain high-octane gasoline with a low content of aromatic hydrocarbons, with practically no decrease or even an increase in the octane number, despite the fact that aromatic hydrocarbons themselves have high octane numbers.

 The method meets the criterion of non-obviousness, because it does not follow from the known technical solutions.

 Examples of specific performance.

EXAMPLE EXAMPLE 1. alyumoplatinorenievom reforming catalyst is subjected to a wide hydrotreated gasoline fraction 75-180 ^{° C,} containing 53.8% paraffins, 29.1% naphthenes and 17.1% aromatics. Hydrocarbons C ₇ -C ₁₀ in the feedstock make up 81% wt. (the rest is C ₆ -C ₅ ). Reforming conditions: pressure 2.5 MPa, temperature 480 ^о . Stable catalysis is obtained with a yield of 82% by weight, the octane number of catalysis is 83 p. method. (91.5 p. According to the research method). The catalyst contains 54.7 wt. % aromatic hydrocarbons, including 5.1% benzene.

Separately subjected to catalytic reforming hydrotreated narrow fraction 62-105 ^{° C} under pressure of 1.6 MPa and other conditions mentioned above. The installation is equipped with an additional reactor connected in series with the reforming reactor. A gas product mixture passes through said reactor together with a recycle hydrogen-containing gas. The narrow gasoline fraction contains 69.6% paraffinic, 27.8% naphthenic, 2.6% aromatic hydrocarbons. The hydrocarbon content of C ₆ -C ₇ in the feed is 97.6% (the rest is C ₅ and C ₈ ).

 Based on the experimental and calculated data, the flow rates in kg / h are given for illustration.

 Given the ratios in the productivity of reforming plants of wide and narrow fractions in industrial practice, the productivity of raw materials for reforming a wide fraction is taken to be 2 times greater, respectively 100 and 50 kg / h. A benzene-containing fraction, which in addition to benzene and other hydrocarbons, contains 9.6% of isohexanes of the potential in the initial catalyst, is isolated from the reforming catalysis of a wide fraction by distillation. It also contains 6.4% toluene of its potential in catalysis.

 At a productivity of 100 kg / h, 18.7 kg / h of the benzene-containing fraction and 63.3 kg / h of a mixture of the head and bottoms fractions of reforming catalysis are obtained from the reforming feedstock.

 The total yield of liquid reforming products of a wide fraction of 82 kg / h (82 wt.%). The rest is gaseous reforming products.

 In the table. 1 shows an exploded composition and a balance of the allocation of a benzene-containing fraction.

18.7 kg / h of the isolated benzene-containing fraction is sent to an additional reactor connected to the narrow fraction reforming reactor. The temperature in the auxiliary reactor 330 ^C. The auxiliary reactor loaded with a catalyst containing 50% pentasil, 6% zeolite Y, zeolite, both in the decationized form, 9% MoO _3, 0.4% Pd, alumina - the rest. The ratio of zeolite pentasil to Y is 8.3.

Stable catalyzate in an amount of 60.2 kg / h is directed to extraction. Get 9.02 kg / h of benzene, 8.21 kg / h of toluene, 1.2 kg / h of aromatic C ₈ , 1.6 kg / h of aromatic C ₉ ⁺ and 40.17 kg / h of raffinate (dearomatized part of the catalysis) . A mixture of raffinate with aromatic hydrocarbons With ₈ ⁺ has an octane number of 70.2 p. (Mot. Met.). The specified stream in the amount of 42.97 kg / h is mixed with 63.3 kg / h of catalytic reforming of a wide fraction, previously freed from the benzene-containing fraction.

 Get 106.27 kg / h of gasoline with an octane rating of 83 p. (Mot. Met.) And an aromatic hydrocarbon content of 41.3%. The total production of liquid products of benzene, toluene and high-octane gasoline is 123.5 kg / h or 82.33% of the total reforming feedstock of a wide and narrow fraction.

 The example shows the possibility of producing high-octane gasoline with an octane number not lower than that of the initial catalytic reforming of the wide fraction and with a significantly lower content of aromatic hydrocarbons in the absence of benzene. The results obtained in this example are shown in table. 2.

PRI me R 2. All conditions correspond to example 1 with the difference that the catalyst for joint processing contains 42% pentasil, 14% zeolite Y, 9% MoO ₃ , 0.4% Pd, the rest is aluminum oxide. The ratio of zeolites pentasil Y = 3. From the co-processing catalysis in the amount of 53.3 kg / h, 8.61 kg / h of benzene, 8.22 kg / h of toluene, 1.3 kg / h of aromatic С ₈ ⁺ are extracted by extraction, 1, 7 kg / h of aromatic C ₉ ⁺ , 33.47 kg / h of raffinate. A mixture of raffinate with aromatic C ₈ ⁺ 36.47 kg / h has an octane number of 71 p. (Mot. Met.). The specified stream is mixed with 63.3 kg / h of reforming catalyst, freed from the benzene-containing fraction. Get 99.77 kg / h of gasoline with about. including 83.9 p. (mot. met.) and an aromatic hydrocarbon content of 44.2%. The total yield of liquid products is 116.6 kg / h, which is 77.73% of the raw materials of both reforming units. The yield of liquid products is significantly lower (by 4.5%) than in Example 1. Example 2 illustrates the minimum ratio of pentasil and Y zeolites at which good results are achieved.

 The data of example 2 are given in table. 2.

PRI me R 3. All conditions correspond to example 1 with the exception of the catalyst for joint processing, which contains 53.34% pentasil, 2.66% zeolite Y, 9% MoO ₃ , 0.4% Pd, the rest is aluminum oxide.

 The ratio of zeolites pentasil and Y 20. The results of the experiments in example 3 are shown in table. 2. In contrast to example 1, the octane number of the obtained gasoline is 82.8 p. Slightly lower than the initial reforming catalysis, noticeably lower and the release of benzene 8.2 kg / h against 9.02 kg / h. Nevertheless, gasoline with a significantly lower content of aromatic hydrocarbons of 41.2% is obtained than in the initial catalyst. An example shows that even with a zeolite ratio of 20, a good effect is achieved.

 Example 4. The conditions and the catalyst are the same as in example 1, the difference is that when the benzene-containing fraction is isolated, the selection of isohexanes is 2% of the potential in the catalyst for the wide fraction. Toluene selection is 1%.

 The release of the benzene-containing fraction is 14 kg / h, the rest of the reforming catalysis is 68 kg / h. The octane number of the benzene-containing fraction is 53 p. (Mot. Met.).

 The results of joint processing are given in table. 2.

 The octane number of the obtained gasoline is 1 p. Lower than the initial reforming catalysis (82 p. Against 83 p.), Lower and the release of benzene 7.92 against 9.02 kg / h. Nevertheless, low aromatic gasoline is obtained (aromatic hydrocarbon content 41.9%), i.e., even with a low selection of isohexanes and toluene, the main objective of the invention is achieved.

 PRI me R 5. The conditions and catalyst are the same. that in example 1, the differences are that when the benzene-containing fraction is isolated, the selection of isohexanes is 50% of their content in the feed, and the selection of toluene is 25%. The release of the benzene-containing fraction is 25 kg / h, its oct. number 64.2 p. (mot. met.). The release of the rest of the catalysis is 57 kg / h. The results of joint processing are given in table. 2.

 Although under the given conditions a high benzene output of 9.12 kg / h and a low aromatic hydrocarbon content in high-octane gasoline (42%) are achieved, the total liquid product output is markedly reduced by 79.5%. From the results it follows that it is not necessary to increase the selection of isohexanes over 50% when isolating the benzene-containing fraction.

PRI me R 6. The conditions and the catalyst correspond to example 1, except for the temperature of the joint processing, which is 380 ^about C.

Under these conditions, a satisfactory release of benzene of 8.42 kg / h is ensured. The resulting gasoline has a high octane number of 84.4 p. With a low content of aromatic hydrocarbons, but the total release of liquid products is reduced - 77.66%. Therefore, a further increase in temperature above 380 ^about With impractical.

PRI me R 7. All conditions and the catalyst are the same as in example 1, but the temperature of the joint processing of 270 ^about C. Release of the catalysis of the joint processing of 62 kg / h, benzene 9.2 kg / h, toluene 8.3 kg / h aromatic C ₈ 1.1, aromatic C ₉ ⁺ 0.5, raffinate 42.9 kg / h.

26.7 kg / h of this product with an octane rating of 65.5 p. (Mot. Met.) Is mixed with 63.3 kg / h of reforming catalyst freed from the benzene-containing fraction. Get 90 kg / h of gasoline with an octane of 83.6 p. With an aromatic hydrocarbon content of 46.5%. The remainder of the raffinate 17.8 kg / h with about. h. 65.5 is used to compound low-octane gasolines. The example illustrates that the temperature of the joint processing should not be lower than 270 ^о С as the production of high-octane gasoline decreases from 100-106 kg / h (examples 1-6) to 90 kg / h.

 At the same time, the results of the example show that even at such a low temperature of joint processing it is possible to obtain high-quality gasoline due to the use of part of the obtained raffinate for mixing. The results are shown in table. 2.

PRI me R 8 (prototype). Because liquid reformate broad fraction was isolated by distillation of the benzene fraction is 62-95 ° ^C. The yield of this fraction is 19.9 kg / h including: isohexane 3, n-hexane, 3.9, 6.3 isopentanes, n-heptane 1 9, naphthenes 0.7, benzene 4.0, toluene 0.1 kg / h. The octane number of the benzene-containing fraction is 56 p. method. At the same time, 62.1 kg / h of reforming catalysis, devoid of a benzene-containing fraction, is obtained. From the benzene-containing fraction, kg / h of benzene is extracted by extraction, while 16 kg / h of the non-aromatized part of the catalysis remains, which is mixed with liquid reforming products of the wide fraction, and 78.1 kg / h of gasoline with an octane number of 82.5 bp are obtained. method and aromatic hydrocarbon content of 52.3%. The decrease in the content of aromatic hydrocarbons is negligible while reducing the octane number of catalysis.

 For comparison with examples 1-7 to the results of the prototype method add a known method for producing aromatic hydrocarbons of reforming narrow fractions.

 When reforming a narrow fraction, the composition of which is shown in example 1 without additional processing, stable catalysis is obtained at 44 kg / h (88%).

5.7 kg / h of benzene are isolated from stable catalysis by extraction: 7.7 kg / h of toluene, 1.2 kg / h of aromatic С ₈ , 29.4 kg / h of non-aromatic component (raffinate). The raffinate together with aromatic C ₈ in an amount of 30.6 kg / h (octane number 60 p. By the motor method) is mixed with high-octane gasoline obtained by the prototype method. Get 108.7 kg / h of gasoline with an octane rating of 76 p. (By mot. Method). The content of aromatic hydrocarbons is 39.2%. At the same time, 9.6 kg / h of benzene and 7.7 kg / h of toluene are obtained.

 Total liquid products 126 kg / h or 84% on reforming feedstocks.

 The results are presented in table. 2.

 From the results obtained in example 8, it follows that the prototype method cannot obtain a significant reduction in the content of aromatic hydrocarbons in high-octane gasoline. If we dilute this gasoline with raffinate from a reforming unit of a narrow gasoline fraction, then the decrease in the content of aromatic hydrocarbons is accompanied by a strong (by 7 p.) Decrease in the octane number of gasoline, while in the proposed method the octane number even increases. (56) Handbook of Petrochemistry, vol. 2 / Under. ed. Ogorodnikova S. K. M.: Chemistry, 1978, p. 148-166.

 Maslyansky G.N., Shapiro R.N. Catalytic reforming of gasolines, L.: Chemistry, 1985, p. 162.

 Sulimov A.D. Catalytic reforming of gasolines. M.: Chemistry, 1973, p. 53.

 GDR patent N 136397, CL C 10 G 37/10, 1967.

 U.S. Patent No. 3,926,782, 208-64, 1974.

 Shipikin V.V. et al. - Oil refining and petrochemicals, 1983, N 8, p. 3-5.

 Fedorov A.P. et al. - Chemistry and technology of fuels and oils, 1972, N 8, p. 8-1.

Claims (2)

1. METHOD FOR PRODUCING HIGH-OCTANE GASOLINE AND AROMATIC HYDROCARBONS, including catalytic reforming of gasoline fractions, isolation by distillation of the intermediate benzene-containing fraction from liquid reforming products of a wide fraction, isolation by extraction or extractive distillation of aromatic hydrocarbons with separation and mixing the fact that the reforming is subjected to separately wide and narrow fractions containing predominantly hydrocarbons C ₇ - C ₁₀ and C ₆ - C _7, respectively, a benzene-containing fraction containing 2.0 to 50.0 wt. % of isohexane hydrocarbons from their potential content in the liquid product of reforming a wide fraction, is subjected to additional processing together with the gas product stream of reforming a narrow fraction in the presence of a catalyst containing pentasil and zeolite Y in a mass ratio of 3 - 20: 1 at a pressure of reforming a narrow fraction, temperature 270 - 380 ^o C, low molecular weight aromatic hydrocarbons are isolated from the product of joint processing and the product obtained after isolation is partially or completely directed to mixing.  2. The method according to p. 1, characterized in that emit a benzene-containing fraction containing 1.0 to 25.0 wt. % of toluene from its potential content in the liquid product of the reforming of a wide fraction.

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