KR20100057854A

KR20100057854A - Method and apparatus for altering a feed to a reaction zone

Info

Publication number: KR20100057854A
Application number: KR1020107005895A
Authority: KR
Inventors: 루보 저우
Original assignee: 유오피 엘엘씨
Priority date: 2007-08-17
Filing date: 2008-08-06
Publication date: 2010-06-01
Also published as: JP2010536954A; TW200920836A; WO2009025993A2; CN101784642B; WO2009025993A3; JP5631209B2; CN101784642A; KR101568432B1; TWI401311B

Abstract

One exemplary embodiment describes a method of changing the feed to a transalkylation reaction zone by changing the destination of a stream enriched in C9 aromatic hydrocarbons to increase the production of one or more of benzene, toluene, p-xylene and aromatic gasoline blends. It may include. The method may comprise providing a stream enriched in C9 aromatic hydrocarbons from the first fractionation zone containing the effluent from the second fractionation zone. The second fractional distillation zone may produce a stream rich in one or more of benzene and toluene. The C9 aromatic hydrocarbon rich stream may be at least partially included in one or more of the feed to the transalkylation reaction zone and the aromatic gasoline blend.

Description

METHOD AND APPARATUS FOR ALTERING A FEED TO A REACTION ZONE}

FIELD OF THE INVENTION The field of the present invention generally relates to methods and apparatus for altering feed to a reaction zone.

Many aromatic complexes are designed to maximize the yield of benzene and p-xylene. Benzene is a versatile petrochemical structural unit used in many different products based on its derivation, including ethylbenzene, cumene and cyclohexane. In addition, p-xylene is an important structural unit that can be used in the production of polyester fibers, resins and films formed through terephthalic acid or dimethyl terephthalate intermediates.

Aromatic complexes can be configured in a number of different ways depending on the desired product, available feedstock and available investment capital. As one example, other products can be produced, such as toluene and aromatic gasoline blends.

However, market conditions may fluctuate and further increase demand for one or more of these products. As a result, there has been a desire to provide greater flexibility to produce more of a given product, such as benzene, p-xylene, toluene and / or aromatic gasoline blends, depending on market conditions.

Other exemplary embodiments can include a method of altering the feed to the reaction zone to increase the production of one or more of benzene, toluene, p-xylene and aromatic gasoline blends. In general, the method includes providing a stream enriched in C9 aromatic hydrocarbons from a first fractionation zone containing a feed from a second fractionation zone. The second fractional distillation zone may produce a stream rich in one or more of benzene and toluene. Generally, the stream rich in C9 aromatic hydrocarbons is included in the aromatic gasoline blend. Optionally, the process passes the feed through the p-xylene separation zone, (a) feeds through the p-xylene separation zone to increase production of aromatic gasoline blends, and (b) p-xylene production rate. Limiting one of the toluene and aromatic gasoline blend production rates to increase.

Further embodiments may include a method of increasing the production of one or more of benzene, toluene, p-xylene and aromatic gasoline blends. In general, the method includes providing a stream enriched in C9 aromatic hydrocarbons from the first fractionation zone that receives the effluent from the second fractionation zone. The second fractional distillation zone may produce a stream rich in one or more of benzene and toluene. Generally, the stream enriched in C9 aromatic hydrocarbons is at least partially included in at least one of the feed to the reaction zone and the aromatic gasoline blend.

One exemplary embodiment of the present invention may include an aromatic compound production apparatus. The aromatic compound production apparatus may include a first fractional distillation zone, a second fractional distillation zone, and a third fractional distillation zone. In general, the first fractionation zone can provide a stream enriched in C8 ^- aromatic hydrocarbons and a stream enriched in C9 aromatic hydrocarbons, and the second fractionation zone provides benzene and optionally toluene from the transalkylation reaction zone effluent. One or more of the can be separated to provide a feed to the first fractionation zone, and the third fractionation zone can receive a stream rich in C8 ^- aromatic hydrocarbons from the first fractionation zone. Effluent from the third fractionation zone can be directly included in the p-xylene separation zone feed to the p-xylene separation zone.

Other exemplary embodiments can include an aromatic compound manufacturing apparatus. The aromatic compound production apparatus may comprise a first fractionation zone providing a stream enriched in C8 ^- aromatic hydrocarbons and a stream enriched in C9 aromatic hydrocarbons. The first fractionation zone may be in direct communication with the reaction zone and the aromatic gasoline blend to provide at least a portion of the stream enriched for C9 aromatic hydrocarbons to the reaction zone or aromatic gasoline blend.

Further embodiments may include an aromatic compound production apparatus. The aromatic compound production apparatus may include a naphtha hydrotreating zone, a reforming zone, an extraction zone, a p-xylene separation zone, an alkyl exchange reaction zone, a first fractionation zone, and a second fractionation zone. The reforming zone may receive effluent from the naphtha hydrotreating zone. Generally, the extraction zone receives a first fraction from the reforming zone and the p-xylene separation zone receives a second fraction from the extraction zone and the transalkylation reaction zone through the first fractionation zone and the second fractionation zone. do. The first fractionation zone may provide a stream enriched in C8 ^- aromatic hydrocarbons and a stream enriched in C9 aromatic hydrocarbons. Generally, the first fractionation zone is in direct communication with the transalkylation zone and the aromatic gasoline blend to provide at least a portion of the stream enriched in the C9 aromatic hydrocarbon to the transalkylation zone or aromatic gasoline blend. The second fractional distillation zone may comprise a benzene column and a toluene column. In general, the bottoms stream from the toluene column is provided to the first fractionation zone.

Thus, the method can provide flexibility in manufacturing. One advantage is that, depending on market conditions, the production of p-xylene, benzene, toluene or aromatic gasoline blends can be increased.

Brief description of the drawings

1 is a schematic view of an exemplary aromatic compound production apparatus.

2 is a schematic view of another exemplary aromatic compound production apparatus.

Justice

The term "zone" as used herein may mean a place including one or more equipment items and / or one or more subzones. Equipment items may include one or more reactors or reactor vessels, heaters, separators, exchangers, pipes, pumps, compressors, and controllers. In addition, equipment items such as reactors or vessels may further comprise one or more zones or subzones.

As used herein, the term "stream" may be a stream comprising various hydrocarbon molecules such as straight chain, branched or cyclic alkanes, alkenes, alkadienes and alkynes, and optionally other materials such as gases or impurities such as hydrogen, such as heavy metals. have. The stream may also comprise aromatic hydrocarbons and non-aromatic hydrocarbons. In addition, the hydrocarbon molecule may be abbreviated as Cl, C2, C3 ... Cn, where "n" represents the number of carbon atoms in the hydrocarbon molecule and may also be described by the superscript "+" or "-" symbol. have. In this case, for example, a stream described as containing C 3 ^- hydrocarbons comprises hydrocarbons of up to 3 carbon atoms, such as one or more compounds having 3 carbon atoms, 2 carbon atoms and / or 1 carbon atom. can do. In addition, the symbol "A9" may be used hereinafter to denote a C9 aromatic hydrocarbon. In addition, the terms "stream" and "line" may be used interchangeably in the following description.

As used herein, the term “aromatic” may mean a group containing one or more rings of unsaturated cyclic carbon radicals in which one or more carbon radicals may be substituted with one or more non-carbon radicals. Examples of aromatic compounds include benzene having a C6 ring containing three double bonds. Describing a stream or zone as "aromatic" may also imply having one or more different aromatic compounds.

As used herein, the term “untreated stream” refers to a reaction in which one or more compounds of a zone or stream are reacted, including a separation zone, such as a fractional distillation column, adsorber, crystallizer, extractor or other device that separates one or more components from the stream. It may mean a stream that is not treated as a zone. The "untreated" stream may be heated or cooled by a heater, furnace, heat exchanger, cooler or evaporator, or may be combined with other streams.

As used herein, the term “immediately” can mean that a stream is included in or in communication with another stream or other zone as soon as it is treated with a separation zone or reaction zone. The separation zone may separate one or more components from the stream by processes such as fractional distillation, crystallization, adsorption and / or extraction. The reaction zone may react one or more hydrocarbons in the stream in the reactor to convert one or more hydrocarbons to different hydrocarbons. The reaction may be transalkylation or isomerization. However, the stream may be heated or cooled, for example by a heater, furnace, heat exchanger, cooler or evaporator, or may be combined with another stream, even directly contained in or in communication with another stream or other zone. It is thought to be.

As used herein, the term “gasoline blend” means a product that can be blended with other hydrocarbons to produce one or more gasoline products.

As used herein, the term "KMTA" means 1,000 metric tons per year.

As used herein, the term “rich” may generally mean that the amount of compound or compound in the stream is in an amount of at least 50% by weight, preferably at least 70% by weight.

As used herein, the term “substantially” may generally mean that the compound or compound species in the stream is in an amount of at least 90% by weight, preferably at least 95% by weight and at most 99% by weight.

Detailed description of the invention

Referring to FIG. 1, one or more reaction and separation zones, such as naphtha hydrotreating zone 120, reforming zone 140, extraction zone 180, transalkylation reaction zone 220, p-xylene separation zone 410 ), Alkylaromatic isomerization zone 500, first fractional distillation zone 240, second fractional distillation zone 280, third fractional distillation zone 320, fourth fractional distillation zone 340, fifth fractionation An exemplary aromatic compound production apparatus 100 is shown that may include a distillation zone 360 and a sixth fractional distillation zone 380. At least some of these zones are disclosed in US Pat. No. 6,740,788 B1 (Maher et al.) And US 7,169,368 B1 (Sullivan et al.).

The feed to naphtha hydrotreating zone 120 may be provided by line 110 and may be naphtha, pyrolysis gasoline, one or more xylenes and toluene. It is preferred that the feed is naphtha. The naphtha hydrotreating zone 120 may comprise a naphtha hydrotreating machine having a naphtha hydrotreating catalyst. Generally, the catalyst consists of a second component of molybdenum oxide or tungsten oxide and a third component of the inorganic oxide support (typically high purity alumina) together with the first component of cobalt oxide or nickel oxide. Generally, the cobalt oxide or nickel oxide component is in the range of 1 to 5% by weight, and the molybdenum oxide component is in the range of 6 to 25% by weight. The balance of the catalyst may be alumina and the sum of all components amounts to 100% by weight. One exemplary catalyst is disclosed in US Pat. No. 7,005,058 B1 (Towler). Typical hydrotreating conditions include liquid hourly space velocity (LHSV) of 0.5-15 hr ⁻¹ , pressures of 100-1000 psi (690-6900 kPa) and standardization of 20-500 m ³ / m ³ (100 Hydrogen flow of ˜3000 SCFB).

Effluent from naphtha hydrotreating zone 120 may be sent to reforming zone 140 via line 130. In the reforming zone 140, paraffins and naphthenes may be converted to one or more aromatic compounds. Typically, reforming zone 140 is operated at a very high stringency corresponding to producing a gasoline reforming oil of 100-106 octane demand (RON) to maximize production of one or more aromatics. In addition, this high stringency operation removes non-aromatic hydrocarbons from the C8 ⁺ fraction of the reformate, thereby eliminating the extraction of C8 and C9 aromatic hydrocarbons.

In reforming zone 140, the hydrocarbon stream is contacted with the reforming catalyst under reforming conditions. Typically, the reforming catalyst consists of a first component of the platinum group metal, a second component of the modifier metal and a third component of the inorganic oxide support (which may be high purity alumina). Generally, the platinum group metal is 0.01 to 2.0% by weight and the modifier metal component is 0.01 to 5% by weight. The balance of the catalyst composition may be alumina and the sum of all components amounts to 100% by weight. The platinum group metal may be platinum, palladium, rhodium, ruthenium, osmium or iridium. It is preferable that the platinum group metal component is platinum. Metal modifiers may include rhenium, tin, germanium, lead, cobalt, nickel, indium, gallium, zinc, uranium, dysprosium, thallium or mixtures thereof. One reforming catalyst used in the present invention is disclosed in US Pat. No. 5,665,223 to Bogdan. Usually, the reforming conditions are a liquid hourly space velocity of 0.5-15.0 hr ⁻¹ , the ratio of hydrogen to 0.5-10 moles of hydrogen per mole of hydrocarbon feed entering the reforming zone 140 and 69-4830 kPa (10). Pressure of ˜700 psi).

The reformate product from reforming zone 140 may enter line 144 to fourth fractionation zone 340. Fractional distillation zone 340 may include one or more fractional distillation columns, such as column 350. In general, column 350 directs inlet stream through line 348 to the C7 ⁻ fraction and third fractionation zone 320 (described below) exiting the top of column 350 via line 344. It can be separated into a C8 ⁺ fraction exiting from the bottom of 350.

The hydrocarbon stream in line 344 may enter the extraction zone 180. The hydrocarbon stream may be a first fraction from naphtha hydrotreating zone 120 and / or reforming zone 140 after passing through fourth fractionation zone 340. Extraction zone 180 may produce a by-product raffinate stream in line 184 and a stream enriched in one or more aromatics, such as benzene and / or toluene, in line 186, wherein the one or more aromatics are enriched. The stream may be sent to a second fractionation zone 280 (described below). The raffinate stream can be blended into gasoline used as feedstock in an ethylene plant or recycled to aromatics manufacturing apparatus 100 and converted to further benzene. Extraction zone 180 may utilize extraction methods such as extractive distillation, liquid-liquid extraction, or a combined liquid-liquid extraction / extraction distillation method. Exemplary extraction processes are described in Thomas J. Stoodt et al., “UOP Sulfolane Process”, Handbook of Petroleum Refining Processes, McGraw-Hill (Robert A. Meyers, 3 ^rd Ed., 2004), pp. 2.13-2.23. Preferably, extractive distillation is used which may comprise at least one column known as the main distillation column and a second column known as the recovery column.

Extractive distillation can separate components that have approximately the same volatility and have approximately the same boiling point. Typically, solvent is introduced into the main extractive distillation column before the entry point of the extracted hydrocarbon stream. The solvent may affect the volatility of the components boiling at different temperatures to facilitate separation of the components of the hydrocarbon stream. Examples of solvents include tetrahydrothiophene 1,1-dioxide (ie sulfolane), n-formylmorpholine (ie NFM), n-methylpyrrolidone (ie NFP), diethylene glycol, triethylene Glycol, tetraethylene glycol, methoxy triethylene glycol, or mixtures thereof. In addition, other glycol ethers may be suitable solvents alone or in combination with the solvents described above.

At least a portion of the stream enriched in one or more aromatics in line 186 may be combined with the effluent from the transalkylation reaction zone 220 (described below) to enter the second fractionation zone 280. The second fractionation zone 280 may comprise one or more columns. Preferably, the second fractionation zone 280 comprises a plurality of columns, ie a benzene column 290 and a toluene column 300. Benzene column 290 is a stream of benzene rich at the top of column 290 (which may be discharged via line 294) and a bottom stream of at least one aromatic hydrocarbon that is substantially C7 ⁺ hydrocarbons (line 298). Through toluene column 300) may be generated. Toluene column 300 may separate a toluene rich stream or a stream that is substantially toluene (which may be withdrawn from the top through line 304). At least some of the toluene rich stream may pass through valve 310 to be recovered as product through line 308 and / or at least some of the toluene rich stream may be directed to line 314. Can be recycled through. Optionally, the toluene rich stream in line 314 can be combined with the stream in line 394 and the stream in line 276 as described below. The stream enriched in C8 ⁺ aromatic hydrocarbons can be discharged as an effluent from the bottom of column 300 via line 244 to become a feed to first fractionation zone 240.

In this exemplary embodiment, the first fractionation zone 240 may comprise one or more columns 250. Column 250 may produce three fractions exiting from the top, sides and bottom of the column. The stream enriched in C10 ⁺ aromatic hydrocarbons may be discharged via line 262 to the sixth fractionation zone 380 or via line 404 (described below) to a product such as fuel oil. The stream enriched in C9 aromatic hydrocarbons may be withdrawn as side stream from column 250 via line 258. At least some of the stream may pass through an aromatic gasoline blend, an alkyl exchange reaction zone 220 or both through lines 278 and 276, respectively. In particular, all or part of the stream enriched in C9 aromatic hydrocarbons may be sent to this destination by opening, closing or throttling valve 274 and valve 272, respectively. If a stream enriched in C9 aromatic hydrocarbons is sent to the aromatic gasoline blend, valve 272 is closed such that the stream enriched in C9 aromatic hydrocarbons may pass through line 278 through valve 274 and line 278. Wherein the stream enriched in C9 aromatic hydrocarbons can be sent to an aromatic gasoline blend combined with other components to produce a gasoline product.

If a stream enriched in C9 aromatic hydrocarbons is sent to the transalkylation reaction zone 220, the valve 274 may be closed so that the stream enriched in C9 aromatic hydrocarbons may pass through the valve 272 to line 276. . The stream in line 276 can be combined with the stream in line 318 to enter alkyl exchange reaction zone 220.

The transalkylation zone 220 may produce additional xylenes and benzenes. Without wishing to be bound by any theory, two or more reactions may occur, ie, disproportionation and transalkylation. The disproportionation reaction can react two toluene molecules to form benzene and xylene molecules, and the transalkylation reaction can react toluene and C9 aromatic hydrocarbons to form two xylene molecules. As an example related to the transalkylation reaction, a reactant of 1 mole of trimethylbenzene with 1 mole of toluene can produce 2 moles of xylene, such as p-xylene, as a product. Ethyl, propyl and higher alkyl group substituted C9-C10 aromatic compounds can be converted to lower monocyclic aromatics via dealkylation. As an example, methylethylbenzene may lose ethyl groups through dealkylation to form toluene. Propylbenzene, butylbenzene and diethylbenzene can be converted to benzene through dealkylation. The methyl substituted aromatics, ie toluene, may be further converted to benzene and xylene via disproportionation or alkyl exchange reactions as described above. When the feed to the transalkylation zone has more ethyl, propyl and higher alkyl group substituted aromatics, more benzene can be produced in the transalkylation zone. In general, ethyl, propyl and higher alkyl group substituted aromatic compounds have higher conversion rates than methyl substituted aromatic compounds such as trimethylbenzene and tetramethylbenzene.

In the transalkylation zone 220, the stream from line 224 is contacted with the transalkylation catalyst under transalkylation conditions. It is preferred that the catalyst is a metal stabilized transalkylation catalyst. The catalyst may comprise a solid acid component, a metal component and an inorganic oxide component. The solid acid component is typically pentasil zeolite, which may include the structure of MFI, MEL, MTW, MTT and FER (zeolite nomenclature by the IUPAC committee), beta zeolite or mordenite. It is preferred that the solid acid component is mordenite zeolite. Other suitable solid acid components may include mazzite, NES zeolite, EU-1, MAPO-36, MAPSO-31, SAPO-5, SAPO-11, and SAPO-41. In general, maze zeolites include zeolite omega. Further discussion of zeolite omega and NU-87, EU-1, MAPO-36, MAPSO-31, SAPO-5, SAPO-11 and SAPO-41 zeolites is described in US 7,169,368 B1 (Sullivan et al.). .

Typically, the metal component is a precious metal or a nonmetal. The precious metal may be a platinum group metal of platinum, palladium, rhodium, ruthenium, osmium or iridium. Generally, the base metal is rhenium, tin, germanium, lead, cobalt, nickel, indium, gallium, zinc, uranium, dysprosium, thallium or mixtures thereof. Base metals may be combined with other base metals or precious metals. It is preferable that the metal component contains rhenium. Suitable metal amounts in the transalkylation catalysts are generally in the range from 0.01 to 10%, preferably in the range from 0.1 to 3%, best in the range from 0.1 to 1% by weight. Suitable zeolite amounts in the catalyst are in the range of 1 to 99%, preferably in the range of 10 to 90% and at best in the range of 25 to 75% by weight. The balance of the catalyst may consist of refractory binders or matrices that are optionally used to facilitate production, provide strength, and reduce cost. The binder should be uniform in composition and relatively fire resistant. Suitable binders include inorganic oxides such as one or more of alumina, magnesia, zirconia, chromia, titania, boria, toria, phosphate, zinc oxide and silica. It is preferable that alumina is a binder. One exemplary transalkylation catalyst is disclosed in US Pat. No. 5,847,256 to Ichioka et al.

Typically, the transalkylation reaction zone 220 is operated at a temperature of 200 ° C.-540 ° C. (390 ° F.-1000 ° F.) and a pressure of 690-4140 kPa (100-600 psi). The transalkylation reaction can be carried out over a wide range of space velocities and higher p-xylene ratios are achieved by conversion to higher space velocities. Generally, the liquid hourly space velocity ranges from 0.1 to 20 hr ⁻¹ . The feedstock is preferably transalkylated in the presence of hydrogen in the gas phase. In the case of the transalkylation reaction in the liquid phase the presence of hydrogen is optional. If free hydrogen is present, it is associated with the feedstock and recycled hydrocarbons in an amount of 0.1 to 10 moles per mole of alkylaromatic.

Effluent from transalkylation reaction zone 220 may be discharged through line 228 and combined with the effluent from extraction zone 180 in line 186. The combined stream in line 284 may enter the second fractionation zone 280 as described above.

Referring to the first fractionation zone 240, the effluent from the top of the column 250 may exit through the line 254. This effluent may be combined with the effluent from the fifth fractionation zone 360 from line 364. This combined stream may enter line 366. This combined stream in line 366 may again be combined with the bottom stream from column 350 in the fourth fractionation zone 340 in line 348. These streams can be combined to enter the third fractionation zone 320.

The third fractionation zone 320 may have a column 330 that produces an upper stream in line 334 and a lower stream in line 338 (described below). The top stream is C8 ^- and an aromatic hydrocarbon can be enriched may enter the p- xylene separation zone 410 via line 334. The stream may be a second fraction from the extraction zone 180 and the transalkylation reaction zone 220 after passing through the first fractionation zone 240 and the second fractionation zone 280. In general, the stream in line 334 is directly included in the feed or sent directly to p-xylene separation zone 410.

The p-xylene separation zone 410 may be based on a crystallization process or an adsorptive separation process. Preferably, the p-xylene separation zone 410 is based on the adsorptive separation process. This adsorptive separation can provide a stream that is substantially p-xylene in line 414, such as a stream containing greater than 99 wt% p-xylene. The feed to p-xylene separation zone 410 may direct the molecules to other zones, such as, for example, the transalkylation reaction zone 220, to intercept and limit control valves that produce other products such as benzene and toluene. Can be.

Raffinate from p-xylene separation zone 410 may be depleted of p-xylene to levels typically less than 1% by weight. The raffinate may be sent to the alkylaromatic isomerization zone 500 via line 418, where the equilibrium or near equilibrium distribution of the xylene isomers is reestablished to further produce p-xylene. Any ethylbenzene in the p-xylene separation unit raffinate may be further converted to xylene depending on the type of isomerization catalyst used or may be converted to benzene by dealkylation.

In the alkylaromatic isomerization zone 500, the raffinate stream in line 418 may be in contact with the isomerization catalyst under isomerization conditions. Typically, the isomerization catalyst consists of a molecular sieve component, a metal component and an inorganic oxide component. The molecular sieve component allows to control the catalyst performance between ethylbenzene isomerization and ethylbenzene dealkylation depending on the overall demand for benzene. As a result, the molecular sieve may be zeolitic aluminosilicate or non-zeolitic molecular sieve. Zeolitic aluminosilicate (or zeolite) components are typically pentasil zeolites comprising structures of MFI, MEL, MTW, MTT and FER (zeolite nomenclature by the IUPAC committee), beta zeolite or mordenite. Usually, the non-zeolitic molecular sieve is at least one of the AEL constructs, in particular at least one of the SAPO-11 or ATO constructs, in particular MAPSO-31. The metal component may be a precious metal component and may include any nonmetal modifier component in addition to or in place of the precious metal. The precious metal may be a platinum group metal of platinum, palladium, rhodium, ruthenium, osmium or iridium. The base metal may be rhenium, tin, germanium, lead, cobalt, nickel, indium, gallium, zinc, uranium, dysprosium, thallium or mixtures thereof. Base metals may be combined with other base metals or precious metals. Suitable total metal amounts in the isomerization catalyst range from 0.01 to 10%, preferably from 0.01 to 3% by weight. Suitable zeolite amounts in the catalyst may range from 1 to 99%, preferably from 10 to 90%, more preferably from 25 to 75% by weight. The balance of the catalyst consists of an inorganic oxide binder, typically alumina. One exemplary isomerization catalyst for use in the present invention is disclosed in US Pat. No. 4,899,012 (Sachtler et al.).

Typical isomerization conditions include temperatures ranging from 0 ° C. to 600 ° C. (32 ° F. to 1100 ° F.) and pressures from atmospheric pressure to 3450 kPa (500 psi). The liquid hourly hydrocarbon space velocity of the feedstock relative to the catalyst volume may be 0.1-30 hr ⁻¹ . In general, the hydrocarbon is contacted with the catalyst in a mixture with gaseous hydrogen in a mole ratio of hydrogen to hydrocarbon molar ratio of 0.5: 1 to 15: 1 or more, preferably from 0.5 to 10 moles. Liquid phase conditions are used for the isomerization, and typically no hydrogen is added to the alkylaromatic isomerization zone 500.

At least a portion of the effluent from alkylaromatic isomerization zone 500 in line 504 may enter fifth fractional distillation zone 360. Fifth fractionation zone 360 may comprise a column 370 that produces a C7 ^- hydrocarbon enriched top stream, which is to be purged from aromatic compound production apparatus 100 via line 362. Can be. The bottoms stream enriched in C8 ⁺ aromatic hydrocarbons can be produced from column 370 and exit through line 364, and combined with stream in line 254 and combined in line 366 as described above. Can be generated.

With regard to the third fractionation zone 320, the bottom stream enriched in C9 ⁺ hydrocarbons in line 338 may be sent to the sixth fractionation zone 380. Sixth fractional distillation zone 380 includes a column 390 which produces a bottoms stream enriched with C10 ⁺ aromatic hydrocarbons in line 404 where C9 ^- aromatic hydrocarbons are enriched in a top stream enriched with products such as fuel oil. can do. The top stream in line 392 may be sent to the aromatic gasoline blend, recycled to the transalkylation reaction zone 220, or split at these two destinations in any ratio. If at least a portion is provided to the aromatic gasoline blend, the stream passes through valve 398 and combines with the stream in line 278 and then exits the aromatic compound manufacturing apparatus 100 via line 400. Can be. If at least some are recycled, the stream in line 392 may pass through valve 396 and line 394 to line 314. The combined stream in line 318 may be combined with the stream in line 276. This combined stream may be recycled to the transalkylation reaction zone 220 via line 224 as described above.

In an alternative embodiment, at least a portion, preferably all, of the effluent from the first fractionation zone 240 is blocked from flowing to line 364 such that p-xylene through valve 264 and line 256 is blocked. May pass to a feed of separation zone 410. In addition, at least a portion, preferably all, of the bottoms stream in line 262 closes the inlet of zone 380 and passes the stream in line 262 to fuel oil via line 406 and valve 408. Pass through line 404 for the same product to bypass the sixth fractionation zone 380. In this embodiment, the first fractionation zone 240 partitions the components in line 244 well to provide most of the C8 ^- hydrocarbons in line 254 and most of the C9 hydrocarbons in line 258. This alternative destination is preferred if most of the C10 ⁺ hydrocarbons are provided in line 262.

2, another exemplary aromatics generating unit is shown. The aromatics production unit 600 has a column 250 having only the top stream 254 and the bottom stream 262 (when the aromatic gasoline blend has an incorrect end requirement and the line 406 and the valve 408 are omitted). Which may be particularly effective) is substantially the same as the aromatic generating unit 100 described above. Bottom stream 262 enriched in C9 ⁺ aromatic hydrocarbons may be passed through valve 272 and recycled through line 276 to the transalkylation reaction zone 220 and / or passed through valve 274 to line 278 and line 400 may be passed to the aromatic gasoline blend. Bottom stream 262 may be split at any ratio between these two destinations. Line 266 also communicates with line 262 to provide a purge, for example, fuel oil product from aromatics manufacturing apparatus 600. Heavy hydrocarbons may be purged from the aromatics manufacturing apparatus 600 by opening, closing, or deadlocking the valve 270.

In operation in apparatus 100 and apparatus 600, various amounts of benzene, toluene, aromatic gasoline blends and / or p-xylene may be produced. Valves, in particular valves 396 and 398 and / or any of valves 272 and 274, may be opened, closed or deadlocked to the transalkylation reaction zone 220 and the aromatic gasoline blend. By adjusting the recycle amount respectively, the product yield can be reduced or increased. For example, referring to FIG. 1, C9 aromatic hydrocarbons may be provided by line 392 from the sixth fractionation zone 380 for the apparatus 100 and from the first fractionation zone 240. May be provided by line 258. More streams of benzene can be produced by sending the stream from line 258 to the aromatic gasoline blend, and also sending at least a portion of the stream in line 392 through line 394 and limiting p-xylene production. . Alternatively, the stream from line 258 is sent via line 276 to the transalkylation reaction zone 220, the valve 274 is closed, the flow through the valve 398 is increased, and p − Limiting xylene production can increase aromatic gasoline blend production. Toluene production may be further increased by opening valve 272 and valve 310 and reducing the flow through valve 398 to limit the production of p-xylene and aromatic gasoline blends. In addition, p-xylene production may be increased by opening valve 274 and limiting flow through valve 398 to limit the production of aromatic gasoline blends. Referring to FIG. 2, at least a portion of the stream from line 262 (instead of line 258 in FIG. 1) may be sent to the transalkylation reaction zone 220 or the aromatic gasoline blend to achieve similar product flexibility. .

If the first fractionation zone 240 partitions the components in line 244 well, at least a portion of the effluent in line 254 containing mostly C8 ^- hydrocarbons from the first fractionation zone 240, Preferably all can pass to the feed of p-xylene separation zone 410 via valve 264 and line 256 as described above.

The valve 264, the valve 270, the valve 272, the valve 274, the valve 310, the valve 312, the valve 396, the valve 398 and the valve 408 may be regulating valves. It can be deadlocked to allow at least some of the hydrocarbons associated with each of its lines to pass through.

Thus, the device 100 and the device 600 may further provide the flexibility to produce various products as described in the examples below.

Exemplary Embodiments

The following examples are intended to further illustrate this process. This illustration of embodiments of the invention is not intended to limit the claims of the invention to the specific content of this embodiment. This example is based on engineering calculations and practical operating experience in similar processes.

In this exemplary embodiment, the aromatic compound manufacturing apparatus 100 shown in FIG. 1 is generally the same supply in each example at the same conditions, such as the same feed rate and LHSV, except for the flow rates described in Table 1 below. Raw material composition, hydrogen to hydrocarbon mole ratio, reactor pressure, catalyst, catalyst distribution and catalyst circulation rate are used.

Example

In Comparative Examples 1 and 2-4, a small amount of toluene / benzene feed mixture is added to the aromatic generating unit.

Comparative example One

In this comparative example, the first fractionation zone 240 was omitted and the bottom stream from the second fractionation zone 280 in line 244 was sent to line 328 to transfer the third fractionation zone 320. Combined with feed for. In addition, the valve 310 was closed and the valve 312 was opened to recycle toluene to the transalkylation reaction zone 220.

Example 2 to 4

In the following three embodiments, valve 310 was closed and valve 312 could be opened to recycle all fractionated toluene to alkyl exchange reaction zone 220 as shown in FIG. 1.

Example 2

In this embodiment, closing the valve 272, opening the valve 312 and the valve 274, and limiting the amount of recycle through the line 394 by the valve 396 deadlock to secure p-xylene production This could increase the benzene yield.

Example 3

In another example, the aromatic gasoline blend is increased by closing valve 274, opening valve 272, and limiting recycle through line 394 by valve 396 deadlock to fix p-xylene production. I could make it.

Example 4

In another example, by closing the valve 274, opening the valve 272, limiting the amount of product through the valve 396 (and correspondingly increasing the recycle through line 394) aromatic gasoline By fixing the blend generation it was possible to increase the amount of p-xylene in line 414.

Comparative example 5

In this comparative example, as in Comparative Example 1, the first fractionation zone 240 was omitted and the bottom stream from the second fractionation zone 280 in line 244 was transferred to line 328 to provide a third fractionation. Combined with feed for zone 320. However, valve 310 was opened to recover at least a portion of toluene as a product.

Example 6 to 8

In the next three embodiments, the valve 310 could be opened to recover at least a portion of the toluene in the line 304 as a product.

Example 6

In this embodiment, the p-xylene yield could be increased by closing the valve 274, opening the valve 272, and fixing the toluene and aromatic gasoline blend production rates.

Example 7

In this another embodiment, the valve 272 could be closed, the valve 274 opened, and the p-xylene and aromatic gasoline blends could be fixed to increase the benzene production rate and reduce the toluene production rate.

Example 8

In further embodiments, the toluene production rate could be increased by closing valve 274, opening valve 272, and fixing the aromatic gasoline blend and p-xylene production rates.

The results of Examples 1-8 are listed in Table 1 as KMTA and in Table 2 as x1,000 lb / hr.

TABLE 1

(All units are KMTA)

TABLE 2

(All units are × 1,000 lb / hr)

Examples 2 and 3 demonstrate the flexibility of producing benzene or aromatic gasoline blend production. The difference is benzene 50 KMTA (13,000 lb / hr) [490-440 KMTA (123,000-111,000 lb / hr)] and aromatic gasoline blend 77 KMTA (19,000 lb / hr) [432-509 KMTA (109,000-128,000 lb / hr) )]. Example 4 demonstrates the flexibility of increasing p-xylene production. Example 4 produced 21 KMTA (5,300 lb / hour) more p-xylene with 1221 KMTA (307,700 lb / hour) compared to the p-xylene 1200 KMTA (302,400 lb / hour) produced in Example 1 441 KMTA (111,000 lb / hr) produced less 15 KMTA (3,800 lb / hr) with 441 KMTA (111,000 lb / hr) compared to the benzene 456 KMTA (115,000 lb / hr) produced by Example 1. Similar flexibility for the same or different products is described in Examples 5-8, where toluene is also the product from the aromatic production unit. Accordingly, these examples further demonstrate the flexibility of the device disclosed herein.

In an embodiment, the aromatic compound production apparatus may comprise a first fractionation zone providing a stream enriched in C8 ^- aromatic hydrocarbons and a stream enriched in C9 aromatic hydrocarbons. The first fractionation zone may be in direct communication with the reaction zone and the aromatic gasoline blend to provide at least a portion of the stream enriched for C9 aromatic hydrocarbons to the reaction zone or aromatic gasoline blend. Optionally, the first fractionation zone may comprise a column providing a stream enriched in C8 ^- aromatic hydrocarbons as an upstream stream and a stream enriched in C9 aromatic hydrocarbons as a bottom stream, or a stream enriched in C9 aromatic hydrocarbons May be provided in the side stream, and the bottoms stream may be rich in C10 ⁺ aromatic hydrocarbons.

In an embodiment, the aromatic compound production apparatus further comprises a second fractionation zone for separating one or more of benzene and toluene from a reaction zone comprising an transalkylation reaction zone to provide a feed to the first fractionation zone. Can be. Optionally, the second fractional distillation zone comprises a benzene column and a toluene column, wherein the toluene-rich top stream from the toluene column is combined with a stream enriched in C9 aromatic hydrocarbons before entering the reaction zone. The apparatus for producing an aromatic compound is a p-xylene separation zone containing at least a portion of the C8 ^- aromatic stream from the first fractional distillation zone, an alkylaromatic isomerization containing at least a portion of the p-xylene separation zone effluent from the p-xylene separation zone. And an extraction zone for providing at least a portion of the extraction zone effluent to the second fractionation zone.

Without further elaboration, it is believed that one skilled in the art can, using the above description, utilize the present invention to its fullest extent. Accordingly, the preferred specific embodiments are to be construed as illustrative only and, above all, do not limit the remainder of the disclosure in any way.

In the above description, all temperatures are incorrectly stated in degrees Celsius and all parts and percentages are by weight unless otherwise noted.

From the above description, those skilled in the art can easily identify the essential characteristics of the present invention, and various modifications and changes of the present invention can be made to suit various uses and conditions without departing from the spirit and scope of the present invention.

Claims

A method of changing the feed to a transalkylation reaction zone by changing the destination of a stream enriched in C9 aromatic hydrocarbons to increase the production of one or more of benzene, toluene, p-xylene and aromatic gasoline blends.
Providing a stream enriched in C9 aromatic hydrocarbons from a first fractionation zone containing effluent from a second fractionation zone, said second fractionation zone producing a stream enriched in at least one of benzene and toluene. Wherein the stream enriched in C9 aromatic hydrocarbons is at least partially included in at least one of the feed to the transalkylation zone and the aromatic gasoline blend.
How to include.

The process of claim 1, wherein the first fractional distillation zone further comprises a column providing a stream enriched in C8 ^- aromatic hydrocarbons, a stream enriched in C9 aromatic hydrocarbons and optionally a stream enriched in C10 ⁺ aromatic hydrocarbons. .

3. The method of claim 2, further comprising communicating the purge stream with a stream enriched in C9 aromatic hydrocarbons, wherein the stream enriched in C9 aromatic hydrocarbons is a bottom stream from the column, and optionally the purge stream is included in fuel oil. How to be.

The process of claim 1, wherein the stream rich in C9 aromatic hydrocarbons comprises at least 70% by weight of C9 aromatic hydrocarbons.

The process of claim 1 wherein the first fractionation zone comprises a column to receive the effluent from the second fractionation zone,
Limiting the production of aromatic gasoline blends to alter the feed to the transalkylation reaction zone
&Lt; / RTI >

The method of claim 1,
passing the feed through a p-xylene separation zone,
(a) limiting the feed through the p-xylene separation zone to increase the production of aromatic gasoline blends,
(b) limiting toluene and aromatic gasoline blend formation rates to increase p-xylene production rates
How to include more.

As an aromatic compound manufacturing apparatus,
A first fractionation zone providing a stream enriched in C8 ^- aromatic hydrocarbons and a stream enriched in C9 aromatic hydrocarbons, wherein at least a portion of the stream enriched in C9 aromatic hydrocarbons is directly communicated with the reaction zone and the aromatic gasoline blend to produce a reaction zone. Or a first fractionation zone provided to this aromatic gasoline blend
Aromatic compound production apparatus comprising a.

8. The apparatus of claim 7, wherein the first fractional distillation zone comprises a column providing a stream enriched in C8 ^- aromatic hydrocarbons as a top stream and a stream enriched in C9 aromatic hydrocarbons as a bottom stream. .

8. The first fractional distillation zone of claim 7 wherein said first fractionation zone provides a stream enriched in C8 ^- aromatic hydrocarbons as a top stream, a stream enriched in C9 aromatic hydrocarbons as a side stream and a bottom stream enriched in C10 ⁺ aromatic hydrocarbons. Apparatus for producing an aromatic compound comprising a column provided in a stream.

10. The process of any of claims 7 to 9, further comprising a second fractionation zone for separating one or more of benzene and toluene from the reaction zone to provide a feed to the first fractionation zone. Wherein the reaction zone comprises an alkyl exchange reaction zone.