UA77013C2 - Method for producing the product with reduced sulfur content from liquid hydrocarbon feedstock (variants ) - Google Patents

Abstract

A method for producing a product of reduced sulfur content from an olefin-containing hydrocarbon feedstock which includes sulfur-containing impurities. For this purpose the feedstock is contacted with an olefin-modification catalyst in a reaction zone under conditions which are effective to produce an intermediate product which has a reduced amount of olefinic unsaturation relative to that of the feedstock. The intemediate product is then separated into at least three fractions of different volatility, and the lowest boiling first fraction is contacted with a hydrodesulfurization catalyst in the presence of hydrogen under conditions which are effective to convert at least a portion of its sulfur-containing impurities to hydrogen sulfide. The intermediate boiling fraction is contacted with a selective hydrotreating catalyst in the presence of hydrogen under conditions which are effective to convert at least a portion of its sulfur-containing impurities to hydrogen sulfide.

Description

Description of the invention

The invention relates to a method of removing sulfur-containing impurities from olefin-containing hydrocarbon mixtures. 2 In particular, the proposed method involves the conversion of raw materials into an intermediate product with a reduced bromine number, where this intermediate product is divided into fractions with different boiling points, among which the fraction with a high boiling point is hydrodesulfurized, and the fraction with an intermediate boiling point is selectively hydrogenated.

The suspended catalytic cracking process is one of the refining methods that 710 is used today to convert petroleum into desirable fuels such as gasoline and diesel. In this process, high-molecular hydrocarbon raw materials are converted into low-molecular products by bringing them into contact with hot, fine-grained solid particles of a catalyst in a liquefied or dispersed state. The hydrocarbon feedstock used here naturally boils in the temperature range of about 2052 to 6502 and contacts the catalyst at temperatures in the range of about 4502C to 6502C. Suitable feedstocks for this process are various petroleum fractions such as light gas oils, heavy gas oils, wide boiling gas oils, vacuum gas oils, kerosenes, decanted gas oils, residual fractions, reduced crude gas oils, and recycled gas oils obtained from any from the materials listed above, as well as fractions obtained from oil shale, products of bituminous sand processing and coal liquefaction. The products of the suspended catalytic cracking process are, of course, divided by their boiling points and include light naphtha (with boiling points of about 102 to 2212C), heavy naphtha (with boiling points of about 1092 to 2492), kerosene (with temperatures of boiling from about 1802C to 3002C), light recycled gas oil (with boiling points from about 2212 to 3452C) and heavy recycled gas oil (with boiling points higher than about 3452).

The naphtha product of the catalytic cracking process is a complex mixture of hydrocarbons, including paraffins (also known as alkanes), cycloparaffins (also known as cycloalkanes or naphthenic hydrocarbons), olefins (as used here, the term "olefin" means any acyclic or cyclic hydrocarbon that has at least one double bond and is not aromatic) and aromatic compounds. Such material, of course, has a relatively high olefin content and includes significant amounts of sulfur-containing aromatic compounds, such as thiophene and benzothiophene compounds, which are impurities. For example, light naphtha obtained by catalytic cracking with a suspended catalyst of gas oil obtained from petroleum can contain up to about 3 bObo (wt.) of olefins and up to about 0.790 o (wt.) of sulfur, most of which is in the form of thiophene and benzothiophene compounds However, typical naphtha, which is a product of such a catalytic cracking process, -

335 Typically contains from about 595 (wt.) to 4095 (wt.) olefins and from about 0.0795 (wt.) to 0.575 (wt.) sulfur. uh-

In the United States, the suspended catalytic cracking process not only provides a significant portion of the total gasoline produced, but also imparts a significant amount of sulfur to that gasoline.

Sulfur in the liquid products of this process is in the form of organic sulfur-containing compounds and is an undesirable admixture that turns into sulfur oxides when these products are used in fuels. Oxides « Sulfurs are quite unpleasant air pollutants. In addition, they are able to reduce the activity of many 0s catalysts used in catalytic converters of cars to catalytically convert harmful pollutants in the exhaust gases of their engines into gases that are less harmful. In this connection, it is desirable to reduce the sulfur content in the products of the catalytic cracking process to the lowest possible levels.

A low sulfur content in the products of the catalytic cracking process is achieved by hydrogenation of either the raw materials used in this process or the products themselves. Hydrogenation is the treatment of raw materials with hydrogen in the presence of a catalyst, as a result of which sulfur in sulfur-containing impurities is transformed into

It is hydrogen sulfide, which can be separated and converted into pure sulfur. Such processing can cause the decomposition of olefins in the raw material with their transformation into saturated hydrocarbons as a result of hydrogenation. Such hydrogenation-induced decomposition of olefins is usually undesirable, since, firstly, it absorbs significant amounts of expensive hydrogen and, secondly, olefins are usually valuable high-octane components of se» gasoline. For example, a typical catalytic cracked gasoline boiling range naphtha has a relatively high octane number due to its high olefin content. Hydrogenation of such raw materials leads, as a side effect of the desulfurization process, to a decrease in the content of olefins, and therefore to a decrease in the octane number of the hydrogenated product as the degree of desulfurization increases.

U.S. Patent No. 5,865,988 (Soyipz ei aI.)| a two-stage method of producing gasoline with a low

F) sulfur content from cracked olefinic sulfur-containing naphtha. This method includes: (a) passing naphtha over a form-selective acid catalyst, such as zeolite 25M-5, for selective cracking of low-octane paraffins and conversion of some olefins and naphthenic hydrocarbons to aromatic compounds and aromatic side chains; and (2) hydrodesulfurization of the product formed over a hydrogenation catalyst in the presence of hydrogen. The patent states that initial treatment with a form-selective acid catalyst results in the removal of olefins that would otherwise saturate the product at the hydrodesulfurization stage.

According to the international patent application UUO 98/30655 (Nyty ei a/I.)), published in accordance with the Agreement on Patent BB Cooperation, a method of obtaining a product with a reduced sulfur content from raw materials, which is a mixture of hydrocarbons and contains organic compounds as undesirable impurities, is described sulfur This method involves converting at least part of the sulfur-containing impurities into high-boiling sulfur-containing products by treatment with an alkylating agent in the presence of an acid catalyst and removing at least part of these high-boiling products by dividing them into fractions by boiling point.

U.S. Patent Nos. 5,298,150 (Reispeg et al.), 5,346,609 (Reispeg ei al.), 5,391,288 (Soipv ei ai.) and 5,409,596 (Reispeg ei alI)| described two-stage methods for the production of gasoline with a low sulfur content, where naphtha raw materials are subjected to hydrodesulfurization, followed by treatment with a form-selective catalyst to restore the octane number lost at the stage of hydrodesulfurization.

U.S. Patent No. 5,171,916 (I e ei ai I.)) describes a method of enriching light recycled gas oil by (1) alkylation of heterocyclic aromatic compounds of light recycled gas oil with an aliphatic hydrocarbon containing at least one olefinic double bond, using crystalline metallosilicate catalyst, and (2) separation of the high-boiling alkylation product by fractional distillation. This patent notes that the unconverted light recycle gas oil has reduced sulfur and nitrogen content, and the high boiling alkylation product can be used as a synthetic alkylated aromatic 7/5 functional liquid feedstock.

US Patent No. 5,599,441 (Soviet Union)| disclosed a method of removing thiophene sulfur compounds from cracked naphtha by: (1) contacting naphtha with an acid catalyst in the alkylation zone for alkylation of thiophene compounds using olefins present in naphtha as an alkylating agent; (2) removal of the effluent from the alkylation zone; and (3) separating the alkylated thiophene compounds from the alkylation zone effluent by fractional distillation. It is also noted that the sulfur-enriched high-boiling fraction of fractional distillation products can be desulfurized using conventional hydrogenation or other sulfur removal methods.

U.S. Patent No. 5,863,419 (Niy, Og. ei a) describes a method of catalytic distillation to produce a product with a reduced sulfur content from a raw material that is a mixture of hydrocarbons containing organic compounds of sulfur as undesirable impurities. This method involves simultaneous carrying out of the following process stages in a reactor on a rectification column: (1) conversion of at least part of sulfur-containing impurities into sulfur-containing and) products with a higher boiling point by treatment with an alkylating agent in the presence of an acid catalyst; and (2) removing at least some of these higher boiling products by fractional distillation. It is also noted that the sulfur-enriched high-boiling fraction can be efficiently hydrogenated at relatively low costs due to its reduced volume relative to what it had in the raw material.

A little later |in the US patent Mob,024,865 (Vhyse O. AIehapaeg, Seogde A. Nyi, Mimek K. Rgadpap, UMIat .. --

Keadap, Codeg N. SiIauyup)| described a low-sulfur product obtained from a feedstock that is a mixture of hydrocarbons and includes sulfur-containing aromatic compounds as undesirable impurities. This method provided for the separation of raw materials by fractional distillation into a low-boiling fraction containing more volatile sulfur-containing aromatic impurities and at least one high-boiling fraction containing less volatile sulfur-containing aromatic impurities. After that, all these fractions were separately reduced, as a result of which there was an effective conversion of at least part of its content of sulfur-containing aromatic impurities into higher-boiling sulfur-containing products by alkylation with an alkylating agent in the presence of an acid catalyst. Sulfur-containing products with higher boiling points were removed by fractional distillation. The patent also stated "that alkylation can be carried out in stages if the alkylation conditions are less severe in the initial stage than in the second stage, for example, due to the use of a lower temperature in the first stage and a higher temperature in the second stage." from US patent Mob,059,962 (Vhyse OYU. AIehapaeg, Seogde A. Nyi, Mimek K. Rgadpap, UM/iPShat 9. Keadap, Codeg

N. Siauyup)) described a product with a reduced sulfur content, obtained in a multistage process from raw materials that

IS a mixture of hydrocarbons and includes sulfur-containing aromatic compounds as undesirable impurities. At the first-I stage of this process: (1) raw materials were alkylated with effective conversion of a part of impurities into high-boiling sulfur-containing products and (2) the obtained products were separated by fractional distillation into a low-boiling fraction and

Sh- high-boiling fraction. The low-boiling fraction consisted of hydrocarbons and had a reduced sulfur content compared to the raw material. The high-boiling fraction consisted of hydrocarbons and contained unconverted sulfur-containing aromatic impurities, as well as high-boiling sulfur-containing products. All subsequent stages included: (1) - alkylation of the high-boiling fraction from the previous stage with effective conversion of at least part of its 4) content of sulfur-containing aromatic compounds into high-boiling sulfur-containing products and (2) separation of the obtained products by fractional distillation into a fraction of low-boiling hydrocarbons and a high-boiling fraction , which contained high-boiling sulfur-containing alkylation products. The total low-sulfur hydrocarbon product obtained in this way consisted of low-boiling fractions from various stages of the process.

Another method of reducing the content of sulfur-containing organic impurities in the raw material, which is an ordinary liquid

F) a mixture of hydrocarbons, including olefins, was described (In international application UMO 01/53432, At). This method involved the following operations: (a) bringing the raw material into contact with an olefin modification catalyst in the zone of olefin modification reactions under conditions that allow for the effective production of a product with a bromine number that is lower than the bromine number of the raw material; (B) separation of the product zone of olefin modification reactions into fractions and, in particular, (I) a first fraction containing sulfur-containing organic impurities and having a final distillation temperature in the range of approximately 1259C to 2212C, and (i) a second fraction having more higher boiling point than the first fraction, and contains sulfur-containing organic impurities; and (c) bringing the first fraction into contact with the hydrodesulfurization catalyst in the presence of hydrogen in the desulfurization reaction zone under conditions of effective conversion of at least part of the sulfur in the sulfur-containing impurities of the first fraction to hydrogen sulfide.

The authors of this invention found that sulfur-containing organic impurities in the reaction process in the olefin modification zone form refractory sulfur compounds. The formation of these refractory compounds is undesirable because they can only be treated by conventional hydrodesulfurization means, resulting in undesirable concomitant losses of octane number. These refractory sulfur compounds can be removed by selective hydrogenation. It was also established that these refractory sulfur compounds are concentrated in the product fraction of the zone of olefin modification reactions with boiling points above 2002С. Removal of these compounds can be carried out only by conventional hydrodesulfurization, which leads to saturation with olefins and loss of octane number. In addition, trace amounts of the olefin modification catalyst are leached from the catalyst in the zone of olefin modification reactions and pass into the product of this zone. These compounds or components that 7/0 Contain leached olefin modification catalyst can cause both a decrease in catalyst activity and a pressure drop in any downstream part of the process, for example, in downstream hydrogenators. In addition, it was found that compounds similar to refractory sulfur compounds tend to concentrate in the fraction with a boiling point above 200960.

With the method proposed by the present invention, the problems associated with refractory sulfur compounds and compounds or components containing an olefin modification catalyst can be solved to some extent by separating the product from the olefin modification zone into at least three fractions. Separation of the product of the olefin modification zone into at least three fractions has the advantage that refractory compounds and compounds or components containing leached catalyst can be regenerated in a relatively small volume stream of the highest boiling fraction of the product of the olefin modification zone. The remaining product 20 of the olefin modification zone is divided into at least two fractions, of which the lowest-boiling fraction is relatively desulfurized and can be sent further to the outlet, directly to the gasoline receiving tank, and the intermediate-boiling fraction can be directed to the selective hydrogenation zone, where octane is maintained product number by converting sulfur-containing organic impurities into hydrogen sulfide. To raise its octane number, the intermediate fraction can also be sent to a conventional hydrogenator and then to a reformer. According to the method according to the present invention, the volume of the output stream of the olefin modification zone, for example, from 9095(06.) to 9890(06.), can be divided into two fractions containing small amounts of refractory sulfur and leached i) olefin- modification catalyst and do not undergo octane-reducing hydrodesulfurization.

The highest-boiling fraction can ideally be directed to a conventional diesel or naphtha hydrogenator, or returned to a catalytic cracking unit with a suspended catalyst to remove both refractory and non-refractory sulfur compounds. Leached olefin-modifying compounds or components can be removed with activated aluminum by conventional means known to those skilled in the art before being transferred to the hydrogenator. o "Hydrocarbon liquids" here are such liquids that boil at standard pressure in a wide or narrow range of temperatures ranging from approximately 109C to 3459C. Such liquids are often found in oil refining processes, as well as in the refining of coal liquefaction products and the processing of oil shale or tar sands, and are, as a rule, complex mixtures of hydrocarbons, which may include olefins, cycloparaffins and aromatic compounds. For example, hydrocarbon liquids are light naphtha, heavy naphtha, gasoline, kerosene, and light recycled gas oil. "

Hydrocarbon liquids encountered in refining processes often contain undesirable sulfur-containing impurities,

Kootri should be at least partially removed. Hydrogenation methods are effective and generally applicable for removing sulfur-containing impurities from hydrocarbon liquids. But, unfortunately, conventional hydrogenation methods are usually insufficient for the treatment of high-olefin hydrocarbon liquids, because such processes lead to a significant conversion of olefins to paraffins, which are usually lower in octane. In addition, hydrogenation of olefins requires significant expenditure of expensive hydrogen

According to international publication MUO 01/53432, At), organic sulfur compounds can be removed from -i hydrocarbon liquids using a multistage method, which includes: (a) bringing the raw material into -1 contact with the zone of olefin modification reactions under conditions , which ensure effective production of a product with a bromine number lower than the bromine number of the raw material; (B) separation of the product into two fractions - the first, which has (а) a final distillation temperature in the range from 13592С to 2212С, and a high-boiling fraction; and (c) carrying out the -l 20 hydrodesulfurization reaction of the low-boiling fraction.

But, unfortunately, this process leads to an undesirable loss of octane number due to the fact that the first fraction of sb" is hydrogenated in the usual way, which reduces the octane number due to olefin saturation. In addition, such a process is not aimed at solving the problems associated with the conversion of refractory sulfur compounds into hydrogen sulfide while keeping the octane number within acceptable limits. | moreover, such a process is not designed to overcome the difficulties created downstream from the olefin modification zone by leached compounds or catalyst components, such as increased pressure drop and catalyst deactivation in the downstream process sections. Therefore, in the light of the above, the need for a method that would ensure almost complete removal of sulfur-containing impurities from olefin-containing hydrocarbon liquids and (1) was relatively cheap in its implementation, (2) caused little or no loss of octane number and ( 3) took into account the possibility of solving problems related to refractory sulfur compounds and leached compounds or catalyst components. Such a method could be used, for example, to remove sulfur-containing impurities from hydrocarbon liquids such as suspended catalytic cracking products that are highly olefinic and contain relatively large amounts of sulfur-containing organic materials such as 65 mercaptans, thiophene and benzothiophene compounds, which are undesirable impurities

In search of a suitable solution, the authors of the invention created an improved method, which involves modifying the olefin part of the raw material on an olefin modification catalyst at the olefin modification stage, dividing the products of the olefin modification stage into three fractions according to their boiling points, selective hydrogenation of the fraction with an intermediate boiling point and hydrodesulfurization of initial fractions with the highest boiling temperatures. The olefin modification stage allows to reduce the olefinic unsaturation of the raw material, measured by the bromine number. Thanks to the olefin modification stage, the product obtained at the subsequent stage of selective hydrogenation is depleted in sulfur content and characterized by a new loss of octane number compared to the raw material of the olefin modification stage. In addition, the reduction in the level of olefinic unsaturation at the olefin modification stage results in a corresponding reduction in hydrogen consumption at the 7/o Corresponding stages of selective hydrogenation and hydrodesulfurization, since the processed product now has a reduced number of double olefinic bonds that consume hydrogen in hydrogenation reactions. In one of the variants of the implementation of this invention, a method of producing a product with a reduced sulfur content from raw materials containing sulfur-containing organic impurities and representing a conventional liquid mixture of hydrocarbons, including olefins, is proposed, and the specified method includes: (a) bringing the raw materials into contact with olefins - a modification catalyst in the zone of olefin-modification reactions under conditions that enable the effective production of a product with a reduced bromine number, lower than the bromine number of the raw material; (5) separation of the product from the specified zone of olefin modification reactions to obtain: () a first fraction containing sulfur-containing organic impurities and having a final distillation temperature lower than about 1402; (iii) the second fraction, which is higher boiling than the first fraction, contains sulfur-containing organic impurities and has a final distillation temperature lower than about 2402C; (its) third fraction, which is more high-boiling than the second fraction and contains sulfur-containing organic impurities and refractory sulfur compounds; Ha (c) bringing the second fraction into contact with the selective hydrogenation catalyst in the presence of hydrogen in the selective hydrogenation reaction zone under conditions that enable effective conversion of at least part of i) sulfur in the indicated sulfur-containing impurities of the second fraction into hydrogen sulfide; and (4) bringing the third fraction into contact with the hydrodesulfurization catalyst in the presence of hydrogen in the hydrodesulfurization reaction zone under conditions that enable effective conversion of at least part of the sulfur in the specified sulfur-containing impurities of the third fraction into hydrogen sulfide.

Another variant of the invention is a method of manufacturing products with a reduced sulfur content from raw materials containing sulfur-containing organic impurities and is a conventional liquid mixture of hydrocarbons, including olefins, where the specified method includes: (a) bringing the raw materials into contact with olefins - a modification catalyst in the zone of olefin-modification - 3z5 reactions under conditions that allow to effectively produce a product with a reduced bromine number, lower than the bromine number of the raw material, where the indicated olefin-modification catalyst is an acid catalyst; (5) separation of the product from the specified zone of olefin modification reactions to obtain: () a first fraction containing sulfur-containing organic impurities and having a final distillation temperature lower than about 1209; (ii) the second fraction, which is more high-boiling than the first fraction, contains sulfur-containing organic impurities - c and has a final distillation temperature lower than about 2002; and (its) third fraction, which is more high-boiling than the second fraction, and contains sulfur-containing organic impurities and refractory sulfur compounds; (c) bringing the second fraction into contact with the selective hydrogenation catalyst in the presence of hydrogen in the selective hydrogenation reaction zone under conditions that allow effective conversion of at least part of the sulfur in the indicated sulfur-containing impurities of the second fraction into hydrogen sulfide; and -1 (4) bringing the third fraction into contact with the hydrodesulfurization catalyst in the presence of hydrogen in the hydrodesulfurization reaction zone under conditions that enable effective conversion of at least part of the sulfur in (c) specified sulfur-containing impurities of the third fraction into hydrogen sulfide. -l 20 In another, although not the best, version of the invention, the second fraction is supposed to be sent to the hydrodesulfurization zone, and after it - to the conversion zone to increase the octane number of this fraction, which was reduced in the hydrodesulfurization zone.

The purpose of this invention is to create an improved method of removing sulfur-containing impurities from a hydrocarbon liquid containing a significant amount of olefins.

Another goal of the invention is to create an improved method of effective removal of sulfur-containing impurities from cracked olefin naphtha.

The purpose of this invention is also to create an improved method of desulfurization of cracked olefin naphtha to obtain a product with a practically unchanged octane number.

Another object of this invention is to create an improved method of overcoming the problems associated with refractory sulfur compounds and leached compounds or catalyst components in the process of removing sulfur-containing impurities from a hydrocarbon liquid.

The attached drawing shows a diagram corresponding to one of the variants of the implementation of this invention.

The invention creates a method of manufacturing a product with reduced sulfur content from olefin-containing hydrocarbon liquid distillate containing sulfur-containing impurities. This method can be used in the production of a product that practically does not contain sulfur-containing impurities, has a reduced content of olefins and is characterized by an octane number close to the octane number of the raw material.

The invention provides for bringing the raw material into contact with the olefin modification catalyst in the reaction zone under conditions that allow the efficient production of an intermediate product with a reduced amount of olefinic unsaturation compared to the amount of olefinic unsaturation of the raw material measured by the bromine number. After that, the intermediate product is divided into at least three fractions of different volatility. The fraction of the highest volatility (that is, with the lowest boiling point) contains a relatively small amount of sulfur-containing organic impurities, that is, in general, less than 20x1073 parts by mass of sulfur, and therefore can be directed directly to the original gasoline tank. The second fraction, which is a fraction of the intermediate boiling range, is brought into contact with a catalyst of selective hydrogenation in the presence of hydrogen under conditions that allow to effectively convert at least part of its sulfur-containing organic impurities into hydrogen sulfide. Hydrogen sulfide can be easily removed in conventional ways to obtain a product with a significantly reduced sulfur content compared to the raw material. The third fraction, which is the most high-boiling, is brought into contact with the hydrodesulfurization catalyst in the presence of hydrogen under conditions that allow for the effective conversion of at least part of the sulfur-containing organic impurities and refractory sulfur compounds into hydrogen sulfide. Hydrogen sulfide can be easily removed by conventional methods to give a product with a significantly reduced sulfur content compared to the raw material.

Aromatic sulfur-containing impurities in the feedstock, such as thiophene and benzothiophene compounds, undergo at least partial conversion in the olefin modification reaction zone to higher-boiling sulfur-containing products, some of which may be recognized as refractory sulfur compounds, as discussed in more detail below. . This transformation is obviously the result of alkylation of aromatic sulfur-containing impurities with olefins in the presence of an olefin-modifying catalyst. After fractionation of the feed liquor from the olefin modification reaction zone, most of these high-boiling sulfur-containing materials, including refractory sulfur compounds, appear in the third or high-boiling fraction, while the first lowest-boiling fraction and the intermediate-boiling fraction have relatively low sulfur content. with that of the raw material, which enters the olefin modification zone.

In the best embodiment of the invention, the second fraction is brought into contact with the catalyst of selective i9) hydrogenation in the presence of hydrogen under conditions that allow to effectively convert at least part of the sulfur-containing impurities of this fraction into hydrogen sulfide. This operation can be carried out using one of the currently licensed selective hydrogenation methods, such as the ZSAMInpip method, co-licensed by EhhopMori! Kevzeagsp apa Epdipeegipd Sotrapu, and the RKIME-StJ method, licensed by IBR corporation Mogii Ategisa Ips., or using the generally accepted method of hydrogenation under conditions -- selective hydrogenation, which are less rigid and allow the desulphurization process to occur with the limitation of av! olefin saturation. Such methods of selective hydrogenation are also described (in US patents Mob,007,704 (Spariz ega!.), Mob,821,397 (doiu ei a.) and Mob,255,548 (Riyaop ei a/!.)|. -

The third fraction is brought into contact with the hydrodesulfurization catalyst in the presence of hydrogen under conditions that allow to effectively convert at least part of its sulfur-containing impurities, including refractory sulfur compounds, into hydrogen sulfide. A large part of the sulfur-containing impurities of the high-boiling fraction or fractions often consists of aromatic sulfur-containing compounds, such as thiophene and benzothiophene compounds, as well as "refractory sulfur compounds, which are much more difficult to remove by hydrodesulfurization than mercaptans and thiophene compounds. According to this, the best version of this invention includes the use of more stringent hydrodesulfurization conditions. and Raw materials that can be processed according to this invention consist of conventional mixtures of liquid "" hydrocarbons containing olefins and boiling in the temperature range from approximately 102 to 3452С, measured according to the AZIM O 2887 - 97a method, described, for example, in (1999 Appiai! VookK oi ABTM 8(apaagaz, besiop 5, Reyigoyesht Rgodisiv, I tsbgisapiv, apa RovzviI ERtseiv, MoI. 05.02, rade 200), incorporated here in its entirety -I by reference, or by other widely known relevant methods. In addition In addition, suitable feedstocks are -1 feedstocks that include a mixture of hydrocarbons boiling in the gasoline range. If necessary, such feedstocks may also contain significant amounts of low-volatile hydrocarbon components with boiling points (α) above that of the specified high-volatile fraction. Hence, a suitable feedstock is a Shu 20 conventional liquid mixture of hydrocarbons with a horse distillation temperature of up to about 3459C and better if up to about 24920. In the best version, the starting temperature the boiling point of the raw material is about 792C, and its final distillation temperature does not exceed about 345922. Suitable raw materials include any complex mixtures of hydrocarbons that are usually found in oil refining processes, such as natural gas gasoline, lignin, light gas oil, heavy gas oils and gas oils with a wide fractional composition, as well as hydrocarbon fractions obtained by means of coal liquefaction processes and fuel processing processes

GF! shale or bituminous sands. The best raw materials consist of olefin-containing hydrocarbon mixtures from the processes of catalytic cracking or coking of hydrocarbon raw materials. Catalytic cracking products are especially preferred as a raw source of hydrocarbons for use in this invention. Materials of this type include liquids that boil at temperatures below 60 approximately 3459, such as light naphtha, heavy naphtha, and light recycle gas oil. However, it is clear that in practice, all the initial volatile products of the catalytic cracking process can be used as a source of raw hydrocarbons for use in this invention. Catalytic cracked products are a desirable source of raw hydrocarbons because they usually have a relatively high olefin content and, of course, contain significant amounts of organic sulfur compounds as impurities. For example, light naphtha from bo gas oil, obtained by catalytic cracking of petroleum with a suspended catalyst, may contain up to about b00 (wt) olefins and up to about 0.795 (wt) sulfur, with most of the sulfur in it being in the form of thiophene and benzothiophene compounds In addition, sulfur-containing impurities can usually include mercaptans and organic sulfides. The preferred feedstock for use in this invention consists of catalytic cracking products containing at least 190 (w/w) olefins. The best feedstock consists of catalytic cracking hydrocarbons and contains at least 1095 (wt) olefins. Particularly preferred is a feedstock consisting of catalytic cracking hydrocarbons and containing at least 1595 (wt) or 2095 (wt) olefins.

In one of the variants of implementation of the invention, the raw material for use in it is a mixture of low molecular weight olefins with hydrocarbons from the output of the catalytic cracking process. Such raw materials can be 7/0 prepared, for example, by adding olefins containing from 3 to 5 carbon atoms to naphtha from the catalytic cracking process.

In another embodiment of the invention, the raw material is a mixture of naphtha from the catalytic cracking process with a source of volatile aromatic compounds, such as benzene and toluene. Such raw materials can be prepared, for example, by mixing the light conversion product with naphtha from the /5 Catalytic Cracking process. A typical light conversion product contains from about 0 to 295(06.) of olefins, from about 20 to 4595(06.) of aromatic compounds and has a distillation temperature of 1095 ("710") no higher than about 1609 (7122), a temperature of 5095 distillation ("750") not higher than about 2009 (932C), and the temperature of 9095 distillation ("T90") not higher than about 2509 (12122). It is clear that the distillation temperatures given here correspond to the method of measuring AZTM О 86-97, described in (1999 Appia! Vook oi AZTM 2o ZMapagaz, Zesiop 5, ReigoYieit Rgodisiv, I tsBhisapiv, apa RozviiYi Etsei5, MoY. 05.01, rad 16), included herein in its entirety by reference, or by other widely known relevant measurement techniques.

A typical light conversion product contains about 5 to 1595(06.) of benzene.

In another embodiment of the invention, the use of raw materials is provided, which is a mixture of (1) hydrocarbons from the catalytic cracking process, (2) sources of volatile aromatic compounds and (3) sources of olefins containing from 3 to 5 carbon atoms.

Suitable feedstocks for use in this invention contain at least 195(wt) olefins, preferably at least 1095(wt) olefins, even more preferably at least 1595(wt) or 2095(wt) olefins. If necessary, the content of olefins in it can be 5O090b (wt.) or more. In addition, such raw materials can contain from about 0.00590 (wt.) to 2.0 sulfur in the form of its organic compounds. However, a typical raw material generally contains from about 0.0595 (wt) to 0.795 (wt) sulfur in the form of its organic compounds.

The raw material suitable for use in this invention, for example, naphtha from the process of catalytic cracking, may, in addition to sulfur-containing impurities, contain nitrogen-containing organic compounds as impurities. Many typical nitrogen-containing impurities are organic bases and in some cases can cause relatively rapid deactivation of the olefin modification catalyst of this invention. In the event that such deactivation -

335 occurs, it can be prevented by removing the main nitrogen-containing impurities before they come into contact with the olefin modification catalyst. Therefore, in the case where the raw material contains major nitrogen-containing impurities, a preferred embodiment of the present invention includes removing these major nitrogen-containing impurities from the raw material before it is brought into contact with the olefin modification catalyst. In another embodiment of the invention, the raw material used practically does not contain basic nitrogen-containing impurities (such raw material may contain, for example, less than approximately 50x1079 parts by mass of basic nitrogen). At the same time, the raw material, which is processed naphtha, prepared by removing the main nitrogen-containing impurities from naphtha produced by catalytic cracking, is particularly preferable. ,» Major nitrogen-containing impurities may be removed from the raw material or from the material intended for use as a raw material component by any suitable method. Such methods, as a rule, involve treatment with an acidic material, and widespread methods include such operations as washing with an aqueous acid solution or passing the material through a protective layer. In addition, a combination of these methods can be used. The protective layer can consist of such materials as A-zeolite, B-zeolite, I-zeolite, mordenite, fluorinated aluminum oxide, fresh cracking catalyst, balanced cracking catalyst, and acidic (in) polymer resins. When applying the protective layer method, there is often a need to use two protective 20 layers in such a way that during the operation of one protective layer, the other protective layer can be regenerated. If a cracking catalyst is used to remove the main nitrogen-containing impurities, then such material can be regenerated in the regenerator of the catalytic cracking unit when it becomes deactivated, that is, it loses its ability to remove such impurities. If acid washing is used to remove the main nitrogen-containing compounds, then such treatment is carried out with an aqueous solution of the corresponding acid. Suitable acids for this may be, for example, hydrochloric acid, sulfuric acid and acetic acid. The concentration of the acid in the aqueous solution is not critical, but usually lies in the range, approximately, from 0.190 (wt.) to 309b (wt.).

For example, to remove the main nitrogen-containing impurities from heavy naphtha obtained by i) catalytic cracking, 590 (wt.) aqueous solution of sulfuric acid can be used.

The method according to the present invention makes it possible to remove sulfur-containing organic 60 impurities of all types from raw materials with high efficiency. Such impurities, as a rule, are aromatic, sulfur-containing organic compounds, which include all aromatic organic compounds containing at least one sulfur atom. Such materials are thiophene and benzothiophene compounds such as thiophene, 2-methylthiophene, 3-methylthiophene, 2,3-dimethylthiophene, 2,5-dimethylthiophene, 2-ethylthiophene, 3-ethylthiophene, benzothiophene, 2-methylbenzothiophene, 2,3 -dimethylbenzothiophene and

Z-ethylbenzothiophene. Other typical sulfur-containing impurities are mercaptans and organic sulfides and 65 disulfides.

Any material capable of catalyzing the oligomerization of olefins can serve as an olefin modification catalyst according to the present invention. At the same time, it is desirable that the olefin modification catalyst is also capable of catalyzing the alkylation of aromatic organic compounds with olefins. Conventional alkylation catalysts are very suitable for use as olefin modification catalysts according to the present invention, since they are, as a rule, capable of catalyzing both the oligomerization of olefins and the alkylation of aromatic organic compounds with olefins. Conventional alkylation catalysts are particularly suitable for use as olefin modification catalysts, as they are generally capable of catalyzing both the oligomerization of olefins and the alkylation of aromatic organic compounds with olefins. Along with liquid acids, such as sulfuric acid, solid acid catalysts can be used, which are more suitable. Such 7/0 solid acid catalysts can also serve as liquid acids applied to a solid base. Solid catalysts are generally more suitable than liquid catalysts because the raw materials are easier to contact with solid materials. For example, the raw material can simply be passed through one or more fixed catalyst beds in the form of solid particles at the appropriate temperature. Alternatively, the raw material can be passed through a fluidized bed of catalyst in the form of solid particles.

Suitable olefin modification catalysts for use in accordance with the present invention may be materials such as acidic polymer resins, acids on solid bases, and acidic inorganic oxides.

Among the suitable acidic polymer resins, well-known in this field and produced by the industry are sulfonic acid polymer resins. A typical example of such materials is Atreguvzi? 35 produced by the company Kopt apa Naaz So.

Acids on solid bases suitable for use as olefin modification catalysts are, for example, Brønsted acids (phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid

NE, fluorosulfonic acid, trifluoromethanesulfonic acid, dioxyfluoroboric acid) and Lewis acids (for example, ВЕ», ВСИ», AIСиз, АИВгз, РеСи», РесСиз, 7пСи», ЗЕв, ЗББСИв and combinations of АИИСиз and НС) applied to solids, for example, on silicon oxide, aluminum oxide, aluminosilicate, zirconium oxide or clay. In the application of Ha liquid acids applied to a solid base, catalysts on bases are, of course, obtained by combining the desired liquid acids with the desired base and drying. Catalysts based on bases obtained by combining phosphoric acid with a solid base are particularly suitable for use as solid i) phosphoric acid catalysts. The advantage of these catalysts is due to the fact that they are both highly effective and cheap. (U.S. Patent No. 2,921,081, incorporated herein by reference in its entirety, describes a method of preparing solid phosphoric acid catalysts by combining a zirconium compound selected from zirconium oxide and zirconium halides with an acid selected from - - orthophosphoric acid, pyrophosphoric acid and triphosphoric acid. (U.S. Patent No. 2,120,702 (Irayeiyi "3 a!-"), incorporated herein in its entirety by reference, describes a method of preparing solid phosphoric acid catalysts by combining phosphoric acid with a silicon-containing material such as diatomite or kieselguhr.

With respect to solid phosphoric acid obtained by precipitation of phosphoric acid on kieselguhr, the catalyst is believed to contain: (1) one or more free phosphoric acids (such as orthophosphoric acid, pyrophosphoric acid, and triphosphoric acid) carried by the kieselguhr; and (2) phosphates of silicon formed « by the chemical reaction of this acid or acids with kieselguhr. While anhydrous silicon phosphates obviously do not have the activity of an olefin modification catalyst, they can, due to hydrolysis, form a mixture of orthophosphoric and polyphosphoric acids, which acts as an olefin modification catalyst. The exact composition of this mixture depends on the amount of water to which this catalyst is exposed. To maintain the solid "" phosphoric acid alkylation catalyst at a satisfactory level of activity when it is used as an olefin modification catalyst with practically anhydrous raw materials in practice, of course, a small amount of alcohol, for example isopropyl, is added to raw material 5 in order to maintain the catalyst at an acceptable hydration level . It is believed that the alcohol on contact with the catalyst dehydrates, and that the resulting water hydrates the catalyst. If the amount of water in the catalyst is too small, then the catalyst

She tries to acquire a very high acidity, which can lead to its rapid deactivation due to av! coking and, in addition, the catalyst thereby loses satisfactory physical integrity. Further hydration of the catalyst helps to reduce its acidity and reduces its tendency to rapid deactivation due to coking. However, excessive hydration of such a catalyst can cause its softening, physical agglomeration and create large pressure drops in reactors with a stationary bed. In this regard, there is an optimal level of hydration of the solid phosphoric acid catalyst depending on the reaction conditions. Although the present invention is not limited to the use of only solid phosphoric acid catalysts, it has been found that the concentration of water in the raw material in the range of approximately 50x10'? up to 1000x109 parts by mass in the general case allows maintaining a satisfactory level of catalyst hydration. If necessary, this water can be supplied in the form of alcohol, for example, isopropyl, which, obviously, is dehydrated when in contact with the catalyst.

Acidic inorganic oxides suitable for use as olefin modification catalysts 60 include, but are not limited to, alumina, aluminosilicates, natural and artificial granular clays, and natural and artificial zeolites such as foyasites, mordenites, I, omega, X , U, beta and 75M-zeolites. Particularly suitable among zeolites are U, beta, 75M-3, 75M-4, 75M-5, 75M-18 and 75M4M-20. If necessary, zeolites can be embedded in an inorganic oxide matrix, for example, from aluminosilicate.

Mixtures of various materials can be used as olefin modification catalysts, for example, 65 Lewis acids (BEz, VSiz, ZBE, AISiz), non-zeolitic solid organic oxide (aluminum oxide, silicon oxide, and aluminosilicate) and coarse-pored crystalline molecular sieves (for example, zeolites,

granular clays and aluminum phosphates).

In the case of using a solid olefin modification catalyst, its physical form should be such as to ensure quick and effective contact with raw materials in the zone of olefin modification reactions. At the same time, it is desirable that the solid catalyst has the form of particles, the maximum size of which was on average, approximately, from 0.1 mm to 2 cm. For example, practically spherical balls of medium diameter can be used, approximately from 0.0 mm to 2 cm. Alternatively, the catalyst may be in the form of rods with a diameter of approximately 0.1 mm to 1 cm and a length of approximately 0.2 mm to 2 cm.

In the practical application of this invention, the raw material is brought into contact with an olefin-modifying 7/0 catalyst in the olefin-modifying reaction zone under conditions that allow the efficient production of a product with a bromine number lower than the bromine number of the raw material without causing significant cracking of the paraffins in raw materials At the same time, the "bromine number" is determined according to the AZTM O 1159-98 method described in (1999 Appiai

VookK oi ABTM 5iapaagaz, Zesiop 5, Reigoieit Rgodisiv, I irgisapiv, apa RozviiYi Rtseiv, Moi. 05.01, Rule 407), incorporated herein in its entirety by reference. However, other known /5 analytical methods for determining the bromine number can also be used. The bromine number of the product of the olefin modification reaction zone in a preferred embodiment is no more than 8095, better if no more than 70905, and even better if no more than 6595, of the bromine number of the feedstock fed to this reaction zone.

The reaction zone may consist of one or more reactors with a stationary catalyst bed, where the catalysts may be the same or different. A fixed bed reactor may also contain a plurality of 20 catalytic beds. Catalytic layers in one such reactor can also be of the same or different catalysts.

The conditions in the olefin modification reaction zone are chosen so that at least some of the olefins in the feedstock are converted to products of appropriate volatility, acceptable for use as components of fuels such as gasoline and diesel. with

Without imposing any limitations on the present invention, it is assumed that the olefins of raw materials in the zone of olefin-modification reactions are at least partially consumed in various chemical reactions upon contact of i) raw materials with the olefin-modification catalyst in this zone. It is assumed that these specific chemical reactions depend on the composition of the raw materials. These chemical processes obviously include polymerization of olefins and alkylation of aromatic compounds with olefins. The condensation reaction of an olefin or a mixture of olefins on an olefin modification catalyst with the formation of products of higher molecular weight is called a polymerization process, and the products of this process can be low-molecular oligomers or high-molecular polymers. Oligomers are formed as a result of the condensation of two, three or four olefin molecules with each other, while polymers are formed by the condensation of five or more olefin molecules with each other. The term "polymerization" used here in a broader sense means the process of formation of oligomers and/or polymers. As a result of polymerization of olefins, olefinic unsaturation decreases. For example, as a result of simple condensation of two propene molecules, a six-carbon olefin is formed, which has only one olefinic double bond (2 double bonds in the starting materials are replaced by one double bond in the product). Similarly, the result of a simple condensation of three propene molecules is the formation of a nine-carbon olefin, which has only one "olefinic double bond (Z double bonds in the starting materials are replaced by one pl" double bond in the product). . Although the polymerization of olefins is a simplified model that allows us to understand the mechanism of reduction of bromine number in the zone of olefin modification reactions, it is believed that these processes also play a large role.

For example, the initial products of a simple condensation of olefins can undergo isomerization in the presence of an olefin-modifying catalyst with the formation of highly branched monounsaturated olefins. In addition, as a result of polymerization reactions, polymers can be formed, which successively undergo fragmentation in the presence of an olefin modification catalyst with the formation of highly branched products of lower

Sh- molecular weight than the initial product of polymerization. Although this does not impose any limitations on the present invention, it is believed that the following transformations occur in the zone of olefin modification reactions: (1) low molecular weight olefins present in the feedstock are converted to higher molecular weight olefins , which are both highly branched and are included in the gasoline boiling range; and (2) unbranched or 4) moderately branched feedstock olefins are isomerized to highly branched olefins belonging to the gasoline boiling range.

Alkylation of aromatic compounds is also an important chemical process that can occur in the zone of olefin modification reactions and act in the direction of reducing the bromine number of raw materials. Alkylation of an aromatic organic compound with an olefin containing one double bond leads to the breaking of this

F) of the double bond of the olefin and to the replacement of the hydrogen atom in the aromatic ring structure of the base by an alkyl group. This breaking of the double bond of the olefin contributes to the formation of a product in the zone of olefin modification reactions, which has a reduced bromine number compared to the bromine number of the raw material. However, because aromatic organic compounds are very different in their chemical activity as alkylating bases. In Tab. | as an example, values of constant reaction rate characterizing the chemical activity of some typical aromatic compounds in relation to alkylation with 1-nnaphthene at 20492С are given; on a solid phosphoric acid catalyst, where all values of the constant rate were obtained from the steepness of the graph of the function Ip(1-x) versus time, where x is the concentration of the base, constructed from experimental data. 65 As used herein, the terms "sulfur-containing aromatic compound" and "sulfur-containing aromatic impurities" mean any aromatic organic compound containing at least one sulfur atom in its aromatic ring structure. Such materials include thiophene and benzothiophene compounds.

Alkylation of sulfur-containing aromatic compounds, of course, occurs faster than aromatic hydrocarbons.

In this regard, sulfur-containing aromatic impurities can be selectively alkylated to a limited extent in the zone of olefin modification reactions. However, if necessary, the reaction conditions in this zone can be chosen so that significant alkylation of aromatic hydrocarbons does not occur. This embodiment of the invention can be very useful when the raw material contains volatile aromatic hydrocarbons, such as benzene, and it is necessary to convert such material into higher molecular weight alkylation products. This embodiment of the invention is particularly useful when the raw material contains significant amounts of low molecular weight olefins, 70 that is, such olefins containing from 3 to 5 carbon atoms. The products of mono- or dialkylation of benzene with such low molecular weight olefins contain from 9 to 16 carbon atoms and are therefore sufficiently volatile to be used as components of gasoline or diesel fuels. : catalysts. . . . . . . As a result of alkylation of sulfur-containing aromatic impurities in the raw material zone of olefin modification reactions, sulfur-containing products with higher boiling points are formed. Such materials can be removed by (o) dividing the output stream of the reaction zone into fractions based on boiling temperatures. As a rough approximation, each carbon atom in the monoalkylated thiophene side chain adds approximately 259 to the boiling point of thiophene, which is 842. So, for example, 2-octylthiophene has a boiling point of 2592C, which corresponds to an increase of 232C above the boiling point of thiophene from each carbon atom in the eight-carbon alkyl group. Accordingly, monoalkylation of thiophene C 7 -C 5 with an olefin in the olefin modification reaction zone naturally gives (77) a sulfur-containing alkylation product that has a sufficiently high boiling point to be easily removed by fractional distillation as a component of the high-boiling fraction having the temperature of the beginning of boiling is approximately 2105 C. -

Alkylation of a sulfur-containing aromatic compound with an olefin is illustrated by the monoalkylation of thiophene with propylene to give 2-isopropylthiophene or 3-isopropylthiophene. The higher molecular weight of such an alkylation product corresponds to its higher boiling point compared to the starting material. In one of the variants of implementation of the invention, the reaction conditions in the olefin modification zone are selected in such a way that the main part of "sulfur-containing aromatic impurities in the raw material is converted into higher-boiling sulfur-containing products.

Mercaptans are a class of organic sulfur-containing compounds that often appear in significant quantities as impurities in hydrocarbon liquids commonly found in oil refining processes. For example, straight race gasolines obtained by simple distillation of crude oil often contain, as impurities, significant amounts of mercaptans and sulfides. In addition, benzothiophene compounds become relatively inactive under the influence of conditions used in the zone of olefin modification reactions and some polysubstituted thiophenes, such as some 2,9-dialkylthiophenes.In this regard, most of the mercaptans in the feedstock and significant amounts of some relatively -I inactive sulfur-containing aromatic compounds can withstand the reaction conditions in the olefin modification zone.

In the practical implementation of this invention, the raw materials are brought into contact with the olefin-modification 7 catalyst in the zone of olefin-modification reactions at a temperature and for a time corresponding to av! effective reduction of olefinic unsaturation of raw materials, estimated by bromine number. Contacting temperature in this case is preferably above 502C, even better - above 1002C, and even better above 12520. Contacting is generally carried out at a temperature in the range, approximately, from 509C to (45) 3502C, better if in the range, from about 1002 to 3502C, and even better if in the range from about 1259C0 to 2502C. It is clear that the optimal contacting temperature depends on the olefin modification catalyst used, the concentration of olefins in the feedstock, the type of olefins present in the feedstock, and the type of aromatic compounds to be alkylated in the feedstock.

GF! The feedstock can be brought into contact with the olefin modification catalyst in the olefin modification reaction zone at any suitable pressure. At the same time, a pressure range of approximately 0.01 to 200 atmospheres is desirable, with pressure values of approximately 1 to 100 atmospheres being preferable. In the general case, when the raw material is passed through the catalyst bed in a free flow, the pressure should be selected so that the raw material 60 is in a liquid state.

In a particularly preferred embodiment of the invention, the conditions used in the zone of olefin modification reactions are chosen so as to prevent significant cracking of paraffins in the raw material. So, for example, it is desirable that no more than 1095 paraffins were subjected to cracking, better if not more than 595 paraffins, and even better if not more than 195 paraffins. This is due to the fact that, as it is believed, significant cracking of paraffins leads to the creation of undesirable by-products, for example, low-molecular compounds, the consequence of which is the loss of the volume of produced gasoline.

In the practical implementation of this invention, the product stream from the zone of olefin modification reactions is divided into at least three fractions according to their volatility.

At the same time, it is desirable that the temperature of the beginning of distillation boiling of the third, most high-boiling fraction is higher than approximately 20020.

This fraction will have such a concentration of various compounds that it will cause rapid deactivation of the catalyst in downstream selective and conventional hydrogenators. In particular, refractory sulfur compounds are formed in the zone of olefin modification reactions. These compounds at temperatures above 2002 concentrate the product fraction of the zone of olefin modification reactions. Removal of these compounds can only be accomplished by conventional hydrogenation or hydrodesulfurization processes, which adversely affect olefinic saturation, causing loss of octane number. The above-mentioned refractory sulfur compounds have the following structure: morning NI AEN to avvya shu ЕВ her Be et t sshnschya sna va zh sn

DOA in Ya yah i: VE She sei che che:

Bosh where! Oy re 5-b TM Where and ; where. che de: I h. I'm here, I'm sooty: SA: Wa sik, R i. Be nn -iy

If you are a tank,

OKU

He sv c where K2 and K1 have two or more carbon atoms, for example, СоНбв, СзиН7, etc., and one chain has more than five carbon atoms, for example, С5Н.4, СеН с, etc. d. "Therefore, refractory compounds of sulfur are, for example: ШЙ and ШЩ ПИ . га Іё о ся А Б тра. Пейн нку і;

ZE ak, "4 more; and g ev: and I. В щи у Я чж: : Б You are s: Х Sho ssh v se: ОВК от др: Z. Z Kv Ne M: ХОВ sy: ke oo: TV Z

B sho: with their pe and m y. s zn Taz: nen shchi I: Z

Thus, a refractory sulfur compound is thiophene containing seven or more alkyl carbon atoms. "

In addition, trace amounts of olefin modification catalyst may leach from the olefin modification zone, which may enter the product of this zone. Such leached catalyst can cause significant catalyst deactivation and/or pressure drop difficulties in any downstream selective hydrogenator or hydrodesulfurization reactor. Such a leached catalyst is prone "" to the concentration of the fraction that boils at temperatures of 2002С and higher.

Other undesirable compounds concentrated in the fraction with boiling points above 200 2C are nitrogen-containing compounds and dienes. - and the advantage of the method according to the present invention is also that these compounds can be reduced to -1 fraction of a relatively small volume boiling at temperatures of 200 9С and higher. The volume of this fraction can be from 295(06.) to 1095(06.) of the product of the olefin modification zone. In the best version, this volume can be (in) from 2905 (06.) to bob (vol.). -l 20 Thus, the volume of, for example, 90-9895(06.) of the olefin modification product can be divided into two fractions. The first of them, the fraction with the lowest boiling point of 140 2C and below, or better - 12092 and below, can be sent directly to the original gasoline tank. The first, most low-boiling fraction, as a rule, contains almost no sulfur, and the content of the latter in it is less than approximately 50x1075 mass parts, in the best version - less than approximately 30x107? parts by mass, and at best less, 59 than about 20X1075 parts by mass, and therefore can be directly used as a starting component

HF) gasoline mixture. t The intermediate boiling fraction or the second fraction preferably has a final distillation temperature lower than about 240°C and most preferably lower than about 2002. The second fraction is sent to a selective hydrogenation zone where sulfur compounds are removed from it, thus keeping , octane number.

The highest-boiling fraction, the range of boiling temperatures of which is higher than that of the intermediate fraction obtained as a result of product separation of the zone of olefin modification reactions, is brought into contact with a hydrodesulfurization catalyst in the presence of hydrogen under conditions that allow for the effective conversion of at least part of the sulfur into its sulfur-containing organic impurities, including refractory sulfur compounds, into hydrogen sulfide. In a particularly preferred embodiment of the invention, at least part of the fraction or fractions with the highest boiling points are also brought into contact with a hydrodesulfurization catalyst in the presence of hydrogen under conditions that allow for the effective conversion of at least part of the sulfur in their sulfur-containing organic impurities into hydrogen sulfide. Alternatively, the highest-boiling fraction can be sent for recirculation to a catalytic cracking unit with a suspended catalyst.

The hydrodesulfurization catalyst can be any conventional catalyst, for example, one containing a metal of the MI group and/or the MI group applied to a suitable base. At the same time, the metal of the MI group is, as a rule, molybdenum or tungsten, and the metal of the MI group is nickel or cobalt. Their typical combinations are nickel-molybdenum and cobalt-molybdenum. Suitable bases for the catalyst may be, for example, aluminum oxide, silicon oxide, titanium oxide, calcium oxide, magnesium oxide, strontium oxide, barium oxide, coal, zirconium oxide, 70 diatomaceous earth and lanthanide oxides. The best bases for the catalyst are porous bases made of, for example, aluminum oxide, silicon oxide, or aluminosilicate.

The particle size and shape of the hydrodesulfurization catalyst is, of course, determined by how the reagents are brought into contact with the catalyst. For example, the catalyst can be in the form of a fixed bed or a fluidized bed.

The conditions of the hydrodesulfurization reaction, which are used in the implementation of this invention, are quite ordinary in nature. For example, the reaction pressure may be from about 15 to 1500 psi. inch (approximately 1.02 to 102.1 atmospheres), the temperature is approximately 5023 to 4502C, and the hourly fluid flow rate is approximately 0.5 to 15. The ratio between the amounts of hydrogen and hydrocarbon supplied to the zone hydrodesulfurization reactions, of course, is about 200 to 500 standard cubic feet per barrel. The degree of hydrodesulfurization depends on the applied hydrodesulfurization catalyst and selected reaction conditions, as well as on the exact nature of sulfur-containing organic impurities in the raw materials supplied to the hydrodesulfurization reaction zone. However, it is desirable that the conditions of the hydrodesulfurization process are chosen so that at least 5095 of the sulfur content in the sulfur-containing organic impurities is converted to hydrogen sulfide, and it is better if such conversion to hydrogen sulfide is at least 75905.

After removal of hydrogen sulfide, the product of the hydrodesulfurization process of the highest-boiling fraction from the zone of olefin modification reactions has a sulfur content of less than 50x1079 parts by mass, in the best version - less than 00x1079 parts by mass, and in an even better version - less than 10x1079 parts by mass. The octane number of this hydrodesulfurization product is at least 9095, preferably at least 9595, and more preferably at least 9795 from the octane number of the raw material of the olefin modification reaction zone. Unless otherwise specified, the term "octane number" used here means the value obtained according to the formula (K-M)/2, where K is the road octane number and M is the motor octane number.

The second product of fractionation with intermediate boiling temperatures from the zone of olefin modification reactions is brought into contact with a selective hydrogenation catalyst in the presence of hydrogen under conditions that allow it to efficiently carry out the selective conversion of at least part of the sulfur into its sulfur-containing organic compounds

From impurities on hydrogen sulfide with minimal hydrogenation of olefins. in.

One of these methods of selective hydrogenation called ZSAMIipipd? licensed by ExhopMoria

Kezeagsp apa Epdipeegipd Sotrapu. This method is a catalytic desulphurization process that uses a catalyst called KT 225, which allows to selectively remove sulfur from naphtha subjected to catalytic cracking with a suspended catalyst with minimal hydrogenation of olefins and, thus, preservation of the octane number. Another method of selective hydrogenation is also known, called RKIME-O m, c) licensed by IRR corporation Moi Ategisa. Ips. This method makes it possible to remove 9895 sulfur from naphtha subjected to catalytic cracking with a suspended catalyst, preserving the octane part, by limiting the olefinic saturation. The method of selective hydrogenation according to the present invention consists in contacting the second fraction, i.e., the intermediate boiling fraction, with a conventional hydrogenation catalyst under the conditions of the selective hydrogenation zone, which are generally less harsh or milder than the conventional conditions and hydrogenation. The conditions of the selective hydrogenation zone are: temperature in the range of approximately 100 C to 3009 C, and pressure in the range of approximately ZOO pounds/sq. inch to bOOlbs/sq. inch and an hourly liquid flow rate in the range of 3 to 10. The ratio of hydrogen to hydrocarbon supplied to the selective hydrogenation zone is in the range of approximately 700 to 2000 standard cubic feet per barrel of feedstock. - 70 At the end of the stage of selective hydrogenation and removal of hydrogen sulfide, the intermediate boiling fraction has a sulfur content of less than approximately 50x1073 parts by mass, preferably less than 30x107? mass parts, and in an even better version - less than 10x109 mass parts. The octane number of this intermediate fraction after selective hydrogenation is at least 9595, preferably at least 9795, and most preferably 9895 from two octane numbers of the raw material supplied to the olefin modification zone.

One of the variants of implementation of the invention is illustrated in the attached drawing. It is shown here that total (F) naphtha, a product of suspended catalytic cracking, flows through line 1 to pretreatment vessel 2. Ligroin raw materials are a mixture of hydrocarbons, consisting of olefins, paraffins, naphthenic hydrocarbons and aromatic compounds, where the content of olefins is approximately from 60 ООбо(wt.) to бОбо(wt). In addition, the input naphtha contains approximately 0.290 (wt) to 0.590 (wt) sulfur in the form of sulfur-containing organic impurities, including thiophene, thiophene derivatives, benzothiophene and benzothiophene derivatives, mercaptans, sulfides, and disulfides. This raw material also contains, approximately, from 5x1076 to 200x1075 mass parts of impurities containing basic nitrogen.

Impurities containing basic nitrogen are removed from the feedstock in the pretreatment vessel 2 by contacting the feedstock with an acidic material such as aqueous sulfuric acid under mild contact conditions that do not cause significant chemical modification of the hydrocarbon components of the feedstock.

The output stream from the pretreatment vessel 2 along line C is fed to the olefin modification reactor 4 with an olefin modification catalyst. When passing through reactor 4, the raw material is brought into contact with an olefin modification catalyst under reaction conditions that allow for the efficient production of a product with a bromine number lower than the bromine number of the raw material coming through line 3. In addition, a significant part of thiophene and benzothiophene impurities is converted here into sulfur-containing material with a higher boiling point, including refractory sulfur compounds, by alkylation with olefins present in the feedstock.

The products of the olefin modification reactor 4 leave through line 5 and are fed into the rectification column 6, where 7/0 They are separated into fractions by distillation. The high-boiling fraction, which is a hydrocarbon mixture that contains alkylated sulfur-containing impurities, including refractory sulfur compounds and leached compounds or catalyst components, is withdrawn from the rectification column 6 through line 7. The intermediate boiling fraction, which has a reduced sulfur content compared to the sulfur content of the original heavy naphtha and the final distillation temperature is less than approximately 2402С, is removed from the rectification column b on line 8. The most 7/5 low-boiling fraction is removed from the rectification column 6 on line 9.

The highest-boiling third fraction from the rectification column b exits through line 7 and is fed to the hydrodesulfurization reactor 11, to which hydrogen is fed through line 10. In reactor 11, the third fraction is brought into contact with the hydrodesulfurization catalyst in the presence of hydrogen under conditions that allow effective conversion of at least part of the sulfur in the sulfur-containing impurities of raw materials from line 7 to 20 hydrogen sulfide. The product of this conversion is withdrawn from reactor 11 through line 12 and, after removal of hydrogen sulfide, has a reduced sulfur content compared to the sulfur content of the feedstock supplied through line 7. The sulfur content of this product is typically less than about 30x10 5 parts by mass.

The intermediate boiling fraction from the rectification column b leaves via line 8 and enters the selective hydrogenation reactor 14, to which hydrogen is also supplied via line 13. The intermediate fraction is brought into contact with He 25 with the selective hydrogenation catalyst in reactor 14 in the presence of hydrogen under conditions that allow efficiently convert at least part of the sulfur in sulfur-containing impurities of raw materials from line 8 into hydrogen sulfide. Product o from reactor 14 comes out through line 15 and, after removing hydrogen sulfide from it, has a reduced sulfur content compared to both the raw material, heavy naphtha, and the raw material supplied through line 8. In this product, the sulfur content is, as a rule, less , than approximately 30x10 mass parts. со 30 The first, lowest-boiling fraction is selected from the rectification column 6 along line 9. The sulfur content in this fraction is, as a rule, 10x1079 parts by mass.

The following examples are intended only to illustrate this invention and are not intended to limit it in any way. them

Example 1

2 Raw naphtha with the following characteristics was brought into contact in the olefin modification in zone according to the present invention. "z z s g" -

B, Distillation according to the method of VTM ОВЕ 1 o.

GF) The olefin modification zone consisted of two stages of a stationary layer of solid phosphoric acid (manufactured by the company 5tsa Spetie, trade name С84-5-01) and had the following operating mode parameters: the temperature was 1729С at the first stage and 1222 at the second stage; pressure 500 pounds/sq. inch; hourly volume flow of liquid 1.5. 60 The starting product of the olefin-modification zone by distillation was divided into three fractions in accordance with the method according to the present invention and two fractions for comparison.

Distillation of the products of the olefin modification zone was carried out on a semi-automatic rectification unit

Eizneg 800 Vepsi-zsaie according to the method of AZTM 02892.

The sample was heated in a Zl flask with a magnetic stirrer in a nitrogen atmosphere. Because the separation into fractions was carried out in a column with a diameter of 18 mm with a 4 mm mesh packing Rgo-rak, which ensured the efficiency of 15 theoretical plates.

The resulting vapor was liquefied in a condenser cooled to -202C, and the distillate was withdrawn in a ratio of 20:4 through a synchronized backflow separator into a cooled receiving tank.

The fraction separation temperature was determined by measuring the steam temperature using a resistance thermometer and an electronic measuring device.

The equipment used made it possible to carry out distillation in a vacuum, but in this experiment the samples were distilled at atmospheric pressure and temperatures adjusted to a pressure of 7 bOmm.

Distillation products were purged with nitrogen and kept refrigerated until further testing. 70 Table I shows the values of the relative amounts of the olefin-modifying ("phosphorus") catalyst, the total amount of sulfur in the compared fractions with different boiling points, including at temperatures below 1002, above 1002 and three fractions with boiling points according to this invention : below 1002, 10020-2009С and above 20020. iv of sulfur, x10-bm.ch. |sulphur sulfur phosphorus 10 -bm part nitrogen number U (mass) x10bm h, x1076 mch. x10bm h, ovo | this | 07717712 10 ve oo gm NYM NN Let's drink to her

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As can be seen from the above table, phosphorus and refractory sulfur are concentrated mainly in the highest boiling fraction, when the output stream of the olefin modification zone is divided into three fractions - according to this invention. The yield of the highest-boiling fractions is relatively small and amounts to 1195 (wt), thus allowing to process much smaller product fractions of the olefin modification zone in the processes of octane number recovery and hydrodesulfurization. It should be noted that in the compared cubic fraction the yield is 50.195 (wt.) and indicates that half of the output stream of the olefin modification zone is obviously hydrogenated to remove refractory sulfur indiscriminately, leading to an undesirable loss of octane number twice, that is, much more compared to the 1195 flow yielding the method of the present invention. ssh s Example 2

Raw naphtha with the characteristics described below was brought into contact in the olefin modification zone in accordance with this invention. in - and o -5 with "

Pre-casting according to the DyaTM method of 10 mass fractions of impurities

The above-described raw material was brought into contact with the olefin-modification zone, which contained a stationary layer of solid phosphoric acid (manufactured by Zcii Spetiye, trade name C84-5-01). The processing process in the 65 olefin modification zone took place at a temperature of 1932C and a pressure of 250 pounds per square meter. inch and an hourly volumetric flow rate of 1.5.

The product of the reaction zone was divided into three fractions according to the present invention and two fractions for comparison in the installation with the following characteristics: - reactor volume: "1500 gallons; - column height: 34 feet 6 inches; - column diameter: 12 inches with structured padding; - number of theoretical plates: 33

Separation into three fractions was carried out by distilling the product under atmospheric conditions to a temperature of the main part of the column of 1002С. Distillation products, selected before reaching a temperature of 80 9C of the main 7/0 part of the column, amounted to 3375, before reaching a temperature of 90 C of the main part of the column - 1495, and before reaching a temperature of 100 "C of the main part of the column - 895. After that, the column was irrigated with a general flow phlegm The receiving tank, which contained the fraction with an initial boiling point of 1002C, was disconnected. Next, a reduced pressure mode of 55 mm Hg was set in the installation. and began the next product selection. Part of the product selected in the temperature range of 100-2002C was from 595 to 8905.

When the temperature of the main part of the column reached 106292 at a pressure of 155 mm Hg, the installation was turned off.

The 1000-2002 fraction, the boiler fraction with a final boiling point of 2002, and the vacuum trap fraction were cut off from the installation.

The separation of two fractions for comparison was carried out in a similar way, resulting in a fraction with an initial boiling point of up to 1002C and a fraction with an initial boiling point above 100290.

The table below shows the distribution of sulfur in the corresponding three fractions obtained according to the present invention. It can be seen that the carried out separation into fractions was far from ideal, since the fraction with an initial boiling point of up to 100 C showed the presence of thiophenes SSZ, which are usually absent in this fraction. sch o ve

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The compared fraction with a boiling point above 1002 was subjected to conventional hydrogenation under the following conditions: - - temperature 3182C; syu - pressure 450 lb./sq. inch; - hourly volume flow of liquid 3.

The side fraction or the fraction from 100 to 2002C, obtained according to this invention, was selectively hydrogenated under the following conditions: - temperature 3072C; iF) - pressure 450 lb./sq. inch; ko - hourly volume flow of liquid 3.

With the help of an experimental installation of a downward flow for hydrogenation in a one-stage process, because the treatment of ligroin and distillate was carried out at a hydrogen pressure of up to 200Olbs./sq. inch, hydrogen consumption up to 5 standard cubic feet per hour, liquid raw material consumption b00cmZ/hr. and temperatures up to 8002E (-4272С).

The reactor had an internal diameter of approximately 0.96 inches and a length of 18 inches, could hold up to 120 cm3 of catalyst, and was heated by a salt bath. The temperature inside the catalyst bed was controlled using a programmable single-point thermocouple. The precision pump OS Sopzvia Meiyis 3200 pumped the raw materials and the flow of hydrogen into the reactor through the Vgook5 mass flow meter. The combined streams of liquid and gas were passed through the downflow reactor and separated on a Stramen sight glass (5igaytap).

The off-gas pressure was monitored using a Rosemount pressure sensor (Cozetocpi) and a Badger control valve (Waddeg) where the off-gas flow was passed through a caustic scrubber and measured at atmospheric pressure flow using an A. Wright wet testometer (AIehapaeg M/gd). Control of the level of the liquid product in the separator was carried out using a Rosemount differential sensor and a control valve

Badger. The product was cooled using a tube-in-tube type heat exchanger and collected in a cooler, passing it through a pipeline with an automatic valve controlled by computer software to one of three product receiving tanks. Computer control and data collection were carried out with the help of analog devices Mas 600 of the company Apasd UOemisez, and the automatic protective shutdown of 7/o was provided by the system TI505 RI-S of the company zZietepz Zitais.

Table MI below shows the results of octane retention using this invention with effective deep desulfurization. It can be seen here that the sulfur level in the combined overhead and intermediate fraction (side draw) would be much lower if the fractionation had been carried out in an ideal manner. In particular, the combined first and second fractions (upper shoulder and side extraction) show a loss of octane number 75 from 87.3 to 84.5 during desulfurization to BOx109 mass parts, while the compared method provided sulfur removal only up to 60x109 mass parts parts with a similar loss of octane number. These results would be more significant if the fractionation was perfect. In addition, in order to achieve the level of sulfur in the products of the compared combined fraction, the conditions of hydrodesulfurization should be much stricter and be: - temperature 33220; - pressure 450 lb/sq. inch; - hourly volume flow of liquid 1.5.

Such harsher desulfurization conditions would result in a further loss of octane at 33.395 stream. with schi dvfashi Fo

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Claims (19)

. "» The formula of the invention 1. The method of obtaining a product with a reduced sulfur content from raw materials that contain sulfur-containing organic impurities and is an ordinary liquid mixture of hydrocarbons, including olefins, which is characterized by the fact that it includes: -And (a) bringing the raw materials into contact with an olefin modification catalyst, at least in one zone of olefin modification reactions under conditions that allow to effectively produce a product that has a bromine number o lower than the bromine number of the raw material and which contains refractory sulfur compounds; - about 70 (5) separation into fractions of the product from the specified zone of olefin modification reactions to obtain: c () the first fraction containing sulfur-containing organic impurities and having a final distillation temperature lower than approximately 140 2C; (iii) a second fraction, which is higher boiling than the first fraction, and which contains sulfur-containing organic impurities and has a final distillation temperature lower than about 240 oC; and 59 (its) third fraction, more high-boiling than the second fraction, and which contains sulfur-containing organic HF) impurities and refractory sulfur compounds; 7 (c) bringing the specified second fraction into contact with the selective hydrogenation catalyst in the presence of hydrogen in the selective hydrogenation reaction zone under conditions that allow for the effective conversion of at least part of the sulfur in the sulfur-containing impurities of the second fraction into hydrogen sulfide; and (4) bringing the specified third fraction into contact with the hydrodesulfurization catalyst in the presence of hydrogen in the hydrodesulfurization reaction zone under conditions that allow for the effective conversion of at least part of the sulfur in the sulfur-containing impurities of the third fraction into hydrogen sulfide. 2. The method according to claim 1, which is characterized by the fact that the raw material contains paraffins, and the conditions of the zone of olefin modification reactions allow to effectively produce a product with a bromine number lower than the bromine number of the raw material, and because less than 10 90 paraffins in the raw material are subjected to cracking . C. The method according to claim 1, which is characterized in that it also includes removing hydrogen sulfide from the output stream of said selective hydrogenation reaction zone to obtain a desulfurized product containing less than about 50x1073 parts by mass of sulfur. 4. The method according to claim 3, which differs in that the octane number of the desulfurized product is at least 95% higher than the octane number of the raw material that is fed to the olefin modification reaction zone. 5. The method according to claim 1, which differs in that the raw material contains approximately 0.05 to 0.7 95 wt. sulfur in the form of organic sulfur compounds. 6. The method according to claim 1, which is characterized by the fact that it also includes the removal of hydrogen sulfide from the starting product of the hydrodesulfurization reaction zone 70 to obtain a desulfurized product containing less than about 50x10 5 parts by mass of sulfur. 7. The method according to claim 6, which differs in that the octane number of the desulfurized product is at least 90% higher than the octane number of the raw material that is fed to the zone of olefin modification reactions. 8. The method according to claim 1, which is characterized by the fact that the raw material contains basic nitrogen-containing impurities, and the method includes 75 Removing these basic nitrogen-containing impurities before bringing the raw material into contact with the olefin modification catalyst. 9. The method according to claim 8, which differs in that the raw material contains hydrocarbons obtained in the process of catalytic cracking. 10. The method according to claim 1, which is characterized by the fact that the raw material practically does not contain the main nitrogen-containing impurities. 11. The method according to claim 1, which is characterized by the fact that the raw material is a mixture of hydrocarbons boiling in the boiling range of gasoline. 12. The method according to claim 1, which is characterized by the fact that the raw material contains processed naphtha obtained by removing the main nitrogen-containing impurities from naphtha obtained by catalytic cracking. 13. The method according to claim 1, which differs in that the specified third fraction is from 2 to 10,905 vol. of the Ha product from the zone of olefin modification reactions. 14. The method according to claim 1, which is characterized by the fact that the raw material has a temperature of the beginning of boiling lower than i9) about 79 2С, and the final temperature of distillation is not higher than about 345 20. 15. A method of obtaining a product with a reduced sulfur content from raw materials that contain sulfur-containing organic impurities and are a normal liquid mixture of hydrocarbons, including olefins, which is characterized by the fact that it includes: (a) bringing the raw materials into contact with an olefin modification catalyst in the olefin zone -modification reactions under conditions that allow for the effective production of a product that has a bromine number lower than the bromine number of the raw material and which contains refractory sulfur compounds, where the specified olefin modification catalyst av) is selected from the group of solid acid catalysts; (5) separation into fractions of the product from the specified zone of olefin modification reactions to obtain: - () the first fraction containing sulfur-containing organic impurities and having a final distillation temperature lower than approximately 120 C; (ii) a second fraction, which is higher boiling than the first fraction, and which contains sulfur-containing organic impurities and has a final distillation temperature lower than about 200 2C; and "(its) third fraction, more high-boiling than the second fraction, and which contains sulfur-containing organic impurities and refractory sulfur compounds; (c) bringing the indicated second fraction into contact with the selective hydrogenation catalyst in the presence of m hydrogen in the selective hydrogenation reaction zone under conditions that allow for the effective conversion of at least a part of the sulfur in the sulfur-containing impurities of the second fraction into hydrogen sulfide; and (4) bringing the specified third fraction into contact with the hydrodesulfurization catalyst in the presence of hydrogen in the hydrodesulfurization reaction zone under conditions that allow for the effective conversion of at least part of the sulfur in the sulfur-containing impurities of the third fraction into hydrogen sulfide. -1 16. The method according to claim 15, which is characterized by the fact that it also includes the removal of hydrogen sulfide from the output stream of the indicated selective hydrogenation reaction zone with the receipt of a desulfurized product having an octane number, ("which is at least 98 95 from the octane number of the raw material that is fed into zone of olefin modification reactions, shu 70 17. The method according to claim 15, which is characterized by the fact that it also includes the removal of hydrogen sulfide from the output stream of the specified hydrodesulfurization reaction zone with the production of a desulfurized product having an octane number that is at least 97 95 of the octane number of the raw material fed to the olefin zone - modification reactions. 18. The method according to claim 15, which differs in that the raw material contains hydrocarbons, which are products of the catalytic cracking process. 19. The method according to claim 15, which is characterized by the fact that the raw material contains processed naphtha obtained by removing the main nitrogen-containing impurities from naphtha obtained by catalytic cracking. name) 60 b5