JP2014509301A - Method for removing unsaturated aliphatic hydrocarbons from hydrocarbon streams using clay - Google Patents

Abstract

Contacting the hydrocarbon feed with one of an adsorbent comprising clay, acidic molecular sieves, and activated carbon to produce a hydrocarbon effluent having a lower unsaturated aliphatic content as compared to the hydrocarbon feed; A method for removing unsaturated aliphatic compounds from a hydrocarbon feed stream is disclosed. The hydrocarbon feed stream includes aromatic compounds, nitrogen compounds, and unsaturated aliphatic compounds.
[Selection figure] None

Description

[0001] This application claims the benefit of priority of US Provisional Applications 61 / 424,813; 61 / 424,822; and 61 / 424,831, all filed December 20, 2010.
[0002] The present invention relates to a method for removing unsaturated aliphatic hydrocarbons from a hydrocarbon stream. More particularly, the invention relates to removing unsaturated aliphatic compounds from a hydrocarbon stream containing aromatic compounds.

[0003] The use of molecular sieves as catalysts in aromatic conversion processes is well known in the chemical processing and refining industry. Aromatic conversion reactions of great commercial importance include the production of ethyltoluene, xylene, ethylbenzene, cumene, or higher alkyl aromatic compounds, as well as disproportionation reactions such as toluene disproportionation, xylene isomerization Or alkylation of aromatic compounds such as transalkylation of polyalkylbenzene to monoalkylbenzene. Often, the feed to the aromatic conversion processes include aromatic components, i.e. alkylating base, for example, benzene, and C ₂ -C ₂₀ olefin alkylating agent or a polyalkyl aromatic hydrocarbon transalkylation agent . As used herein, terms such as “C ₄ ”, “C ₅ ”, “C ₆ ” and the like indicate the number of carbon atoms per molecule of a hydrocarbon or hydrocarbon species. In the alkylation zone, the aromatic and olefin feed streams can be reacted over an alkylation catalyst to produce an alkylated aromatic compound such as cumene or ethylbenzene. Part or all of the alkylating base can be supplied by other process units including a separate section of the styrene process unit. The polyalkylated benzene is separated from the monoalkylated benzene product and recycled to the transalkylation zone and contacted with benzene on the transalkylation catalyst to produce monoalkylated benzene and benzene.

  [0004] Catalysts for aromatic conversion processes generally include zeolite molecular sieves. Examples include zeolite β (US-4,891,458); zeolite Y, zeolite Ω, and zeolite β (US-5,030,786); X, Y, L, B, ZSM-5, and Ω crystals. Type (US-4,185,040): X, Y, ultrastable Y, L, Ω, and mordenite zeolite (US-4,774,377); and UZM-8 zeolite (US-6,756,030 and US-7,091,390); Aromatic feed streams to the aromatic conversion process often contain nitrogen compounds such as weakly basic organic nitrogen compounds such as nitriles, which are also downstream, such as aromatic alkylation catalysts, at ppm and ppb levels. It is known in the art to act cumulatively to poison, and greatly reduce their useful life. Various guard beds with clays, zeolites, or resin adsorbents are known in the art for removing one or more types of nitrogen compounds from an aromatic hydrocarbon stream upstream of the aromatic conversion process. Examples include US-7,205,448; US-7,744,828; US-6,297,417; US-5,220,099; WO-00 / 35836; WO-01 / 07383; US- 4,846,962; US-6,019,887; and US-6,107,535.

[0005] Nitrogen compounds, particularly unsaturated aliphatic hydrocarbons such as diolefins, are applied to various process streams such as aromatic hydrocarbon feed streams upstream of aromatic conversion processes such as alkylation It has recently been discovered that adsorbents used in guard beds, such as nitrogen-adsorbing zeolites or molecular sieves, may shorten the useful life. These unsaturated aliphatics, such as olefinic compounds, come into contact with aromatic process streams that are contaminated with nitrogen compounds such as benzene streams produced in the styrene process separation section, as well as catalysts or other materials that are susceptible to nitrogen poisoning. It is present in other streams where nitrogen compounds need to be removed before being allowed to run. The presence of particularly highly unsaturated olefinic compounds, such as C ₄ -C ₆ diolefins, in aromatic streams with nitrogen compound contaminants adversely affects the performance of nitrogen adsorbing materials. Without being bound by theory, olefinic compounds and / or other unsaturated aliphatic compounds compete with nitrogen compounds for adsorption sites and / or react with aromatic compounds such as benzene to protect the nitrogen protective bed. It is believed that the lifetime of the nitrogen adsorbent may be shortened by forming a heavy reaction product that accumulates on the adsorbent.

U.S. Pat.No. 4,891,458 US Pat. No. 5,030,786 U.S. Pat. No. 4,185,040 U.S. Pat. No. 4,774,377 US Pat. No. 6,756,030 US Pat. No. 7,091,390 U.S. Pat. No. 7,205,448 U.S. Pat. No. 7,744,828 US Pat. No. 6,297,417 US Pat. No. 5,220,099 International Publication No. 00/35836 International Publication No. 01/07383 U.S. Pat. No. 4,846,962 US Pat. No. 6,019,887 US Pat. No. 6,107,535

  [0006] The present invention relates to a method for removing unsaturated aliphatic compounds such as olefins and / or diolefins present in an aromatic hydrocarbon stream. In one aspect, the present invention allows for a longer life of the adsorbent downstream of the downstream nitrogen removal zone, thereby minimizing the need to regenerate or replace the nitrogen adsorbent.

  [0007] In one aspect, the present invention is a method of treating a hydrocarbon feed stream comprising an aromatic compound, a nitrogen compound, and an unsaturated aliphatic compound. In one form, the method includes adsorbent comprising clay at a contact condition comprising a hydrocarbon feed stream at a temperature of at least 50 ° C. and a presence of water in an amount of at least 50 ppm relative to the hydrocarbon feed stream on a weight basis. Contacting to remove unsaturated aliphatic compounds to produce a treated hydrocarbon stream. In another form, the method comprises treating the hydrocarbon feed stream with an acidic molecular sieve at a contact condition comprising a temperature of at least 25 ° C. and the presence of water in an amount of at least 50 ppm relative to the hydrocarbon feed stream on a weight basis. Contacting to remove unsaturated aliphatic compounds to produce a treated hydrocarbon stream. In yet another aspect, the method contacts a hydrocarbon feed with activated carbon at contact conditions comprising a temperature of at least 50 ° C. and the presence of water in an amount of at least 50 ppm relative to the hydrocarbon feed on a weight basis. Removing unsaturated aliphatic compounds to produce a treated hydrocarbon stream.

  [0008] In another aspect, the invention is a method of making an alkylated benzene compound. The method comprises (i) contacting a hydrocarbon feed stream comprising benzene, an organic nitrogen compound, and a diolefin compound with one of an adsorbent comprising clay, acidic molecular sieves, and activated carbon to remove the diolefin compound. Producing a treated hydrocarbon stream; (ii) sending at least a portion of the treated hydrocarbon stream to a nitrogen removal zone to produce an alkylated base stream; and (iii) at least a portion of the alkylated base stream. Sending to an alkylation zone to produce an alkylated benzene compound;

  [0009] By combining the removal of one or more unsaturated aliphatic compounds from the aromatic stream with the removal of nitrogen, the lifetime of the catalyst in the alkylation zone and / or the unsaturated aliphatic removal zone and the alkylation zone Can extend the life of the adsorbent in the nitrogen removal zone that can be placed between the two. Furthermore, the removal of reactive unsaturated aliphatic hydrocarbons such as olefins and / or diolefins can minimize the loss of benzene and other desired aromatic compounds that are recycled to react. Unexpectedly, adsorbents containing clays produced diolefins having 4 to 6 carbon atoms per molecule rather than removing the entire mixture of unsaturated aliphatic hydrocarbons in the hydrocarbon feed stream. It has been found to be more selective with respect to removal.

  [0010] The present invention removes one or more unsaturated aliphatic hydrocarbon compounds from a feed stream to produce a treated hydrocarbon stream by one of an adsorbent comprising clay, acidic molecular sieves, and activated carbon. The present invention relates to a method for treating a hydrocarbon feed stream. The treated hydrocarbon stream has a lower unsaturated aliphatic hydrocarbon content compared to the hydrocarbon feed stream. The hydrocarbon feed stream of the present invention includes aromatic compounds, nitrogen compounds, and unsaturated aliphatic compounds.

  [0011] The aromatic hydrocarbon compound can be selected from the group consisting of benzene, naphthalene, anthracene, phenanthrene, and substituted derivatives thereof, with benzene and its derivatives being preferred aromatic compounds. The aromatic compound has one or more substituents selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, a hydroxyl group, and the alkyl group also having an alkoxy group containing 1 to 20 carbon atoms. It may be. When the substituent is an alkyl or alkoxy group, a phenyl group may be substituted on the alkyl chain.

  [0012] In the practice of the present invention, unsubstituted and monosubstituted benzenes, naphthalenes, anthracenes, and phenanthrenes are used in most cases, but polysubstituted aromatic compounds can also be used. Examples of suitable alkylatable aromatic compounds include, in addition to those shown above, biphenyl, toluene, xylene, ethylbenzene, propylbenzene, butylbenzene, pentylbenzene, hexylbenzene, heptylbenzene, octylbenzene, etc .; phenol , Cresol, anisole, ethoxy-, propoxy-, butoxy-, pentoxy-, hexoxy-benzene and the like. Produces naphtha reforming unit, product stream from aromatic extraction unit, styrene monomer production unit, and paraxylene and other aromatic compounds as source of benzene, toluene, xylene, and / or other feed aromatic compounds Recirculation flow from the petrochemical complex. The hydrocarbon feed stream may contain one or more aromatic hydrocarbon compounds. In one aspect, the concentration of aromatics in the hydrocarbon feed stream ranges from 5% to 99.9% by weight of the hydrocarbon feed stream. In other embodiments, the hydrocarbon feed stream comprises 50 wt% to 99.9 wt% aromatics and may comprise between 90 wt% and 99.9 wt% aromatics.

  [0013] The hydrocarbon feed stream nitrogen compound may comprise one or more organic nitrogen compounds. Organic nitrogen compounds are usually basic such as a large proportion of indoles, pyridines, quinolines, diethanolamine (DEA), morpholines such as N-formylmorpholine (NFM), and N-methylpyrrolidone (NMP). Contains nitrogen compounds. Organic nitrogen compounds can also include weakly basic nitriles such as acetonitrile, propionitrile, and acrylonitrile. As discussed below, the present invention does not require, but includes, the use of an optional nitrogen removal zone that reduces the nitrogen content of the hydrocarbon stream.

  [0014] In one embodiment, the hydrocarbon feed stream has a nitrogen content in the range of 1 ppmw to 10 ppmw. In another aspect, the concentration of the organic nitrogen compound in the hydrocarbon feed stream ranges from 30 ppbw (weight ppb) to 1 mol% of the hydrocarbon feed stream; It may be in the range of 100 ppbw to 100 ppmw (ppm by weight). In one aspect, the concentration of the weakly basic organic nitrogen compound, such as nitrile, in the hydrocarbon feed stream ranges from 30 ppbw to 100 ppmw of the hydrocarbon feed stream.

[0015] The hydrocarbon feed stream comprises one or more unsaturated aliphatic compounds, such as unsaturated cyclic hydrocarbons and linear and branched olefinic hydrocarbons (olefins) having one or more double bonds. Thus, the terms “olefin” and “olefinic hydrocarbon” as used herein include diolefin compounds. In one aspect, the unsaturated aliphatic compound may be an olefin compound and the unsaturated aliphatic compound may be a diolefin compound. In one aspect, the unsaturated aliphatic compound is one or more diolefin compounds having 4, 5, or 6 carbon atoms per molecule, ie, the unsaturated aliphatic compound is a C ₄ diolefin, C ₅ diolefins, C ₆ diolefins, and may be selected from the group of diolefins mixtures thereof. In other embodiments, the diolefin compound is selected from the group consisting of butadiene, pentadiene, methylbutadiene, hexadiene, methylpentadiene, dimethylbutadiene, acetylene, and mixtures thereof.

  [0016] In one aspect, the concentration of the diolefin compound in the hydrocarbon feed stream ranges from 30 ppbw to 3000 ppmw in the hydrocarbon feed stream; the concentration of the diolefin compound is from 50 ppbw to 2000 ppmw in the hydrocarbon feed stream. It may be a range. The hydrocarbon feed stream may contain other olefins such as monoolefins. Typically, the total concentration of all olefins in the hydrocarbon feed stream is 1.0 wt% or less olefins.

  [0017] In one embodiment, the aromatic compound comprises benzene, the nitrogen compound comprises an organic nitrogen compound, and the unsaturated aliphatic compound comprises an olefin compound. In other embodiments, the aromatic compound comprises benzene, the nitrogen compound comprises an organic nitrogen compound, the unsaturated aliphatic compound comprises a diolefin compound, and in some cases the diolefin compound has 4 to 6 carbons per molecule. Has atoms.

  [0018] In one approach, the adsorbent used in the present invention comprises clay. Suitable clays include, for example, beidellite, hectorite, laponite, montmorillonite, nontonite, saponite, bentonite, and mixtures thereof. Examples of suitable commercially available clay adsorbents include F series adsorbents available from BASF, and TONSIL adsorbents such as CO630G and CO616GS available from Sud-Chemie. In one aspect, the clay adsorbent is an acid activated bentonite and / or montmorillonite clay.

[0019] In another approach, the method includes the use of activated carbon. Activated carbon is well known in the art and can be derived from various sources such as petroleum coke, coal, wood, and plant shells such as coconut shells using carbonization and / or activation treatment steps. Activation, e.g. CO _{2, H} 2 _O, and by heat treatment in an atmosphere of a mixture thereof, by a chemical process, and it is possible to perform a combination of these. Suitable activated carbon is commercially available, for example from Calgon.

[0020] In yet another approach, the method includes the use of acidic molecular sieves to adsorb or otherwise remove unsaturated aliphatic compounds from hydrocarbon feed streams. Suitable acidic molecular sieves include various forms of silicoaluminophosphate and aluminophosphate disclosed in US-4,440,871; US-4,310,440; and US-4,567,029; And zeolite molecular sieves. As used herein, the term “molecular sieve” is an adsorbent desiccant that is highly crystalline in nature, has a crystallographically defined microporosity or channel, and is different from materials such as γ-alumina. Is defined as one type. A preferred type of molecular sieve within this type of crystalline adsorbent is an aluminosilicate material commonly known as zeolite. The term “zeolite” generally refers to a group of natural and synthetic hydrated metal aluminosilicates, many of which are crystalline in nature. The calcined form of the zeolite molecular sieve has the general formula:
Me _{2 / n} : Al ₂ O ₃ : xSiO ₂ : yH ₂ O
(Where Me is a cation, x has a value from 2 to infinity, n is the valence of the cation, and y has a value from 2 to 10)
Can be represented by Typical known zeolites that can be used include chabazite, clinoptilolite, erionite, faujasite, zeolite β (BEA), zeolite Ω, zeolite X, zeolite Y, MFI zeolite, zeolite, also called zeolite D Examples include MCM-22 (MWW), ferrierite, mordenite, zeolite A, zeolite P, and UZM-8 type zeolite (described below). A detailed description of some of the zeolites defined above can be found in DW Breck, ZEOLITE MOLECULAR SIEVES, John Wiley and Sons, New York, 1974.

  [0021] There are significant differences between various synthetic and natural materials in physical properties such as chemical composition, crystal structure, and X-ray powder diffraction patterns. Molecular sieves occur as agglomerates of fine crystals or are synthesized as fine powders and are preferably tableted or pelletized for large scale adsorption applications. The pelletization process is known to be very satisfactory because the sorption characteristics of the molecular sieve are maintained substantially unchanged with respect to both selectivity and capacity. In one embodiment, the adsorbent includes zeolite Y and / or zeolite X having an alumina or silica binder, and / or β-zeolite having an alumina or silica binder. In one aspect, the acidic molecular sieve is zeolite Y.

  [0022] In one embodiment, the molecular sieve is typically used in combination with a refractory inorganic oxide binder. As the binder, either alumina or silica can be mentioned, and the former is preferable, and γ-alumina, η-alumina, and a mixture thereof are particularly preferable. The molecular sieve can be present in the range of 5 to 99% by weight of the adsorbent, and the refractory inorganic oxide can be present in the range of 1 to 95% by weight. In one aspect, the molecular sieve is present in an amount of at least 50% by weight of the adsorbent, more preferably at least 70% by weight of the adsorbent.

  [0023] The molecular sieve in the adsorbent of the present invention is acidic. Using the silicon / aluminum ratio as a measure for the acid level, the silicon / aluminum ratio should be 100 or less in one embodiment and 25 or less in a further embodiment. Cations on the molecular sieve are undesirable. Thus, in the case of zeolite Y and β-zeolite, it may be desirable to perform an acid wash to remove alkali metals such as sodium to expose more acid sites and thereby increase adsorption capacity. There is. This must also be avoided because the transfer of aluminum from the framework into the binder reduces acidity. Inclusion of some levels of alkaline earth and rare earth cations in zeolite X or Y improves the thermal and hydrothermal stability of the framework aluminum and minimizes the amount of framework aluminum moving from the framework. , Sites of various acid strengths are given. The level of cation introduction should be balanced to improve overall acidity and / or hydrothermal stability without causing a reduction in adsorption performance (which can result at higher cation introduction levels). Must be taken. The molecular sieve adsorbent of the present invention may have the same composition as the alkylation catalyst in a downstream reactor such as an alkylation or transalkylation unit. However, if the alkylation catalyst is more expensive than the molecular sieve adsorbent, the composition of the alkylation catalyst and the molecular sieve are preferably different.

  [0024] The treated hydrocarbon feed stream is contacted with one of a clay adsorbent, acidic molecular sieve, and activated carbon in contact conditions to remove one or more unsaturated aliphatic compounds to produce a treated hydrocarbon stream. Let Unsaturated aliphatic compounds can be removed from the hydrocarbon stream by various mechanisms such as adsorption, reaction, and reactive adsorption by the adsorbent. The treated hydrocarbon stream has a lower unsaturated aliphatic compound content compared to the unsaturated aliphatic compound content of the hydrocarbon feed stream.

  [0025] The contact conditions include a temperature of at least 50 ° C. when using a clay adsorbent or activated carbon, and at least 25 ° C. when using an acidic molecular sieve, and at least 50 ppm by weight on a hydrocarbon feedstream. In the presence of water. Water can be present in an amount equal to or greater than the saturation point of the hydrocarbon feed stream at the contact conditions. In one aspect, the water is present in an amount of at least 250 ppm based on the weight of the hydrocarbon feed stream. In other embodiments, the water is present in an amount in the range of 300 ppm to 800 ppm relative to the hydrocarbon feed stream on a weight basis, and the water is an amount in the range of 450 ppm to 700 ppm relative to the hydrocarbon feed stream on a weight basis. Can be present. The amount of water during contact can be controlled in any suitable manner. For example, the water content of a hydrocarbon feed stream can be monitored and controlled by drying the feed stream and / or adding water or water-generating compounds to the feed stream. Water or water-generating compounds can be introduced as a separate stream into the contacting step and the feed stream can be dried to a consistent water level while adding water or water-generating compounds to obtain the desired content.

  [0026] In an approach using a clay adsorbent, the contact temperature may range from 50 ° C to 300 ° C, and the contact temperature may range from 50 ° C to 125 ° C. In other embodiments, the contact temperature may range from 75 ° C to 250 ° C; the contact temperature may range from 100 ° C to 225 ° C. In the approach of using activated carbon to contact the hydrocarbon stream, the contact temperature ranges from 100 ° C to 300 ° C. In other embodiments, the contact temperature may range from 125 ° C to 300 ° C; the contact temperature may range from 150 ° C to 300 ° C. In yet another approach, when the hydrocarbon stream is contacted with an acidic molecular sieve, the contact temperature may be in the range of 25 ° C to 300 ° C and the contact temperature may be in the range of 45 ° C to 115 ° C. In other embodiments, the contact temperature may range from 45 ° C to 110 ° C; the contact temperature may range from 50 ° C to 110 ° C.

  [0027] In embodiments where the clay adsorbent is used to contact the hydrocarbon stream, the amount of water is at least 50 ppm by weight with respect to the hydrocarbon feed stream and the contact temperature is (i) at least 50 ° C .; (Ii) in the range of 50 ° C to 300 ° C; (iii) in the range of 50 ° C to 125 ° C; (iv) in the range of 75 ° C to 250 ° C; or (v) in the range of 100 ° C to 225 ° C. In one aspect, the amount of water is at least 250 ppm by weight based on the hydrocarbon feed, and the contact temperature is (i) at least 50 ° C .; (ii) in the range of 50 ° C. to 300 ° C .; (iii) A range of 50 ° C to 125 ° C; (iv) a range of 75 ° C to 250 ° C; or (v) a range of 100 ° C to 225 ° C. In other embodiments, the amount of water is equal to or greater than the saturation point of the hydrocarbon feed stream at the contact conditions, and the contact temperature is (i) at least 50 ° C; (ii) 50 ° C to 300 ° C. A range; (iii) a range from 50 ° C to 125 ° C; (iv) a range from 75 ° C to 250 ° C; or (v) a range from 100 ° C to 225 ° C. In a further embodiment, the amount of water ranges from 300 ppm to 800 ppm on a weight basis with respect to the hydrocarbon feed, and the contact temperature is (i) at least 50 ° C .; (ii) a range from 50 ° C. to 300 ° C. (Iii) a range from 50 ° C to 125 ° C; (iv) a range from 75 ° C to 250 ° C; or (v) a range from 100 ° C to 225 ° C. In one aspect, the amount of water ranges from 450 ppm to 700 ppm, based on weight, relative to the hydrocarbon feed, and the contact temperature is (i) at least 50 ° C .; (ii) a range from 50 ° C. to 300 ° C .; (Iii) in the range of 50 ° C to 125 ° C; (iv) in the range of 75 ° C to 250 ° C; or (v) in the range of 100 ° C to 225 ° C. In some cases, the contact condition may further include a pressure of 34.5 kPa (g) to 4136.9 kPa (g). In one embodiment, the contacting is performed using a liquid phase or partially liquid phase feed stream. Vapor phase contact can be used.

  [0028] In other embodiments wherein activated carbon is used to contact the hydrocarbon stream, the amount of water is at least 50 ppm by weight with respect to the hydrocarbon feed stream, and the contact temperature is (i) at least 50 ° C; (Ii) in the range of 100 ° C to 300 ° C; (iii) in the range of 125 ° C to 300 ° C; or (iv) in the range of 150 ° C to 300 ° C. In one aspect, the amount of water is at least 250 ppm on a weight basis with respect to the hydrocarbon feed stream and the contact temperature is (i) at least 50 ° C .; (ii) in the range of 100 ° C. to 300 ° C .; (iii) A range of 125 ° C to 300 ° C; or (iv) a range of 150 ° C to 300 ° C. In other embodiments, the amount of water is equal to or greater than the saturation point of the hydrocarbon feed stream at the contact conditions, and the contact temperature is (i) at least 50 ° C; (ii) 100 ° C to 300 ° C. A range; (iii) a range from 125 ° C to 300 ° C; or (iv) a range from 150 ° C to 300 ° C. In a further embodiment, the amount of water is in the range of 300 ppm to 800 ppm, based on weight, relative to the hydrocarbon feed stream, and the contact temperature is (i) at least 50 ° C .; (ii) in the range of 100 ° C. to 300 ° C. (Iii) in the range of 125 ° C. to 300 ° C .; or (iv) in the range of 150 ° C. to 300 ° C .; In one aspect, the amount of water ranges from 450 ppm to 700 ppm, based on weight, relative to the hydrocarbon feed, and the contact temperature is (i) at least 50 ° C .; (ii) a range from 100 ° C. to 300 ° C .; (Iii) range from 125 ° C to 300 ° C; or (iv) range from 150 ° C to 300 ° C. In some cases, the contact condition may further include a pressure of 34.5 kPa (g) to 4136.9 kPa (g). In one embodiment, the contacting is performed using a liquid phase or partially liquid phase feed stream. Vapor phase contact can be used.

  [0029] In other embodiments where the acidic molecular sieve is used to contact the hydrocarbon stream, the amount of water is at least 50 ppm on a weight basis with respect to the hydrocarbon feed stream, and the contact temperature is (i) at least 25. (Ii) in the range of 25 ° C to 300 ° C; (iii) in the range of 45 ° C to 115 ° C; (iv) in the range of 45 ° C to 110 ° C; or (v) in the range of 50 ° C to 110 ° C. In one aspect, the amount of water is at least 250 ppm by weight based on the weight of the hydrocarbon feed, and the contact temperature is (i) at least 25 ° C; (ii) in the range of 25 ° C to 300 ° C; (iii) A range from 45 ° C to 115 ° C; (iv) a range from 45 ° C to 110 ° C; or (v) a range from 50 ° C to 110 ° C. In other embodiments, the amount of water is equal to or greater than the saturation point of the hydrocarbon feed stream at the contact conditions, and the contact temperature is (i) at least 25 ° C; (ii) 25 ° C to 300 ° C. A range; (iii) a range from 45 ° C to 115 ° C; (iv) a range from 45 ° C to 110 ° C; or (v) a range from 50 ° C to 110 ° C. In a further embodiment, the amount of water ranges from 300 ppm to 800 ppm on a weight basis with respect to the hydrocarbon feed, and the contact temperature is (i) at least 25 ° C .; (ii) a range from 25 ° C. to 300 ° C. (Iii) in the range of 45 ° C to 115 ° C; (iv) in the range of 45 ° C to 110 ° C; or (v) in the range of 50 ° C to 110 ° C. In one aspect, the amount of water ranges from 450 ppm to 700 ppm on a weight basis with respect to the hydrocarbon feed, and the contact temperature is (i) at least 25 ° C .; (ii) in the range 25 ° C. to 300 ° C .; (Iii) in the range of 45 ° C to 115 ° C; (iv) in the range of 45 ° C to 110 ° C; or (v) in the range of 50 ° C to 110 ° C. In some cases, the contact condition may further include a pressure of 34.5 kPa (g) to 4136.9 kPa (g). In one embodiment, the contacting is performed using a liquid phase or partially liquid phase feed stream. Vapor phase contact can be used.

  [0030] The bromine index is typically used to assess the unsaturated aliphatic content of hydrocarbon mixtures such as olefins and diolefins. In one aspect, the present invention removes at least 50% of the unsaturated aliphatic compounds from the hydrocarbon feed stream. That is, in this embodiment, the treated hydrocarbon stream has a bromine index up to 50% of the bromine index of the hydrocarbon feed stream. The bromine index of the hydrocarbon stream or mixture used herein is determined using the UOP304 method. In one embodiment where the clay adsorbent is used to contact the hydrocarbon stream, the present invention removes at least 70% by weight of the diolefin compound from the hydrocarbon feed stream; the present invention relates to the diolefin compound from the hydrocarbon feed stream. At least 90% by weight or at least 95% by weight can be removed. In other embodiments where activated carbon is used to contact the hydrocarbon stream, the present invention removes at least 30% by weight of the diolefin compound from the hydrocarbon feed stream; At least 50 wt% or at least 80 wt% can be removed. In other embodiments in which the acidic molecular sieve is used to contact the hydrocarbon stream, the present invention removes at least 50% by weight of the diolefin compound from the hydrocarbon feed stream; At least 70%, or at least 85%, or at least 90% by weight of the compound can be removed. Here, the diolefin content of the hydrocarbon stream or mixture is determined by the UOP980 method. Unless otherwise stated, analytical methods used in the present invention, such as UOP304 and UOP980, are available from ASTM International, 100 Bar Harbor Drive, West Conshohocken, PA, USA.

  [0031] In other embodiments, the present invention sends at least a portion of the treated hydrocarbon stream to a nitrogen removal zone, where the nitrogen removal zone causes the alkyl to have a lower concentration of nitrogen compounds as compared to the treated hydrocarbon stream. The method further includes generating a modified base stream. As discussed above, various methods for removing nitrogen compounds from an aromatic hydrocarbon stream are well known in the art. See, for example, US-7,205,448; US-7,744,828; US-6,297,417, each of which is incorporated herein by reference in its entirety. Briefly, the treated hydrocarbon stream is introduced into a nitrogen removal zone containing at least one adsorbent effective to remove nitrogen. Suitable adsorbents include clays, resins, and zeolites. Normally, clay and zeolite adsorbents are acidic. The nitrogen removal zone contains two adsorbents such as clay or resin adsorbent located upstream of the zeolite adsorbent, and the treated hydrocarbon stream is first contacted with the clay or resin adsorbent to provide an intermediate stream. Which can then be contacted with a zeolite adsorbent. Different operating conditions such as temperature and the amount of water present are disclosed for the use of different adsorbents and multiple adsorbents in the nitrogen removal zone.

  [0032] In one embodiment, the treated hydrocarbon stream is contacted with an adsorbent comprising acidic molecular sieves at nitrogen removal conditions to produce an alkylated base stream having a reduced nitrogen content. In one aspect, the molecular sieve is a zeolite. Known zeolites that can be used are chabazite, also called zeolite D, clinoptilolite, erionite, faujasite, zeolite β (BEA), zeolite Ω, zeolite X, zeolite Y, MFI zeolite, zeolite MCM-22. (MWW), ferrierite, mordenite, zeolite A, zeolite P, and UZM-8 type zeolite (described below). In one aspect, the nitrogen removal conditions comprise a temperature of at least 120 ° C. to 300 ° C. and the presence of water in an amount in the range of 20 ppm to 500 ppm relative to the treated hydrocarbon stream on a weight basis.

  [0033] In other embodiments, the present invention sends at least a portion of the alkylated base stream from the nitrogen removal zone to the alkylation zone, wherein a portion of the alkylated base stream and the alkylating agent are passed through. It further includes contacting with an alkylation catalyst to produce an alkylated benzene product.

  [0034] In the selective alkylation of an aromatic alkylating base with an olefinic alkylating agent catalyzed by an acidic catalyst, the olefin may contain from 2 to at least 20 carbon atoms and is a terminal or internal olefin. May be branched or linear olefins. Thus, the specific nature of the olefin is not particularly important. Common to alkylation reactions is to conduct the reaction under at least partially liquid phase conditions, a criterion that is easily achieved for lower components by adjusting the reaction pressure. Among the lower olefins, ethylene and propylene are the most important representative examples. The olefin feed stream containing the alkylating agent can include ethylene and / or propylene. Typically, the olefin feed stream containing propylene is at least 65 wt% pure and the olefin feed stream containing ethylene is more than 80 wt% pure. Of the remaining olefins, the class of olefins in the detergent range composed of linear olefins containing 6 to 20 carbon atoms with internal or terminal unsaturation is of particular interest. Linear olefins containing 8 to 16 carbon atoms, particularly those containing 10 to 14 carbon atoms, are particularly useful as olefins in the detergent range. The alkylating agent can also be provided by the alkyl component of the polyalkylbenzene in the transalkylation reaction zone. Diethylbenzene, triethylbenzene, and diisopropylbenzene are excellent examples of polyalkylbenzenes that can provide such alkylating agents.

  [0035] A wide range of catalysts can be used in the alkylation reaction zone. Suitable catalysts for use in the alkylation zone include catalysts that do not adversely affect the presence of water. Preferably, a substantial amount of water may be tolerated or desirable in the presence of an alkylation catalyst. By substantial amount of water is meant the concentration of water in the reactants that is preferably introduced into the alkylation zone of at least 50 wppm. The alkylation reaction zone may have a water content as low as 20 wppm, up to more than 200 wppm and up to 1000 wppm or more. A preferred catalyst for use in the present invention is a zeolite catalyst. The catalyst of the present invention is usually used in combination with a heat-resistant inorganic oxide binder. A preferred binder is alumina or silica. Suitable zeolites include zeolite β, ZSM-5, PSH-3, MCM-22, MCM-36, MCM-49, MCM-56, type Y zeolite described in US-5,723,710, and UZM-8 (which includes aluminosilicates and substituted aluminosilicate zeolites described in US-6,756,030), and modified UZM-8 zeolites, such as described in US-7,091,390. UZM-8HS. Each of US-6,756,030 and US-7,091,390 is hereby incorporated by reference in its entirety.

  [0036] The basic configuration of the catalytic aromatic alkylation zone is known in the art. The feed aromatic alkylating base and feed olefin alkylating agent are preheated and charged to generally 1 to 4 reactors in series. A suitable cooling means can be provided between the reactors to compensate for the net exotherm of the reaction in each of the reactors. Suitable for charging any reactor in the alkylation zone with additional feed aromatics, feed olefins, or other streams (eg, a reactor effluent stream or a stream comprising one or more polyalkylbenzenes) Such means can be provided upstream of each reactor or in each reactor. Each alkylation reactor can include one or more alkylation catalyst beds. The present invention encompasses a dual zone aromatic alkylation process such as that described in US-7,420,098, which is hereby incorporated by reference in its entirety.

[0037] The specific conditions for conducting the alkylation reaction depend on the aromatic compound and olefin used. One prerequisite is that the reaction be carried out at least partially under liquid phase conditions. Therefore, the reaction pressure is adjusted so that the olefin is at least partially dissolved and maintained in the liquid phase. For higher olefins, the reaction can be carried out at autogenous pressure. Alkylation conditions typically include pressures in the range between 1379 kPa (g) and 6985 kPa (g). In one aspect, the pressure ranges between 2069 kPa (g) and 4137 kPa (g). Alkylation of aromatics with olefins ranging from C _{2 to} C ₂₀ is carried out at a temperature of 60 ° C. to 400 ° C., preferably 90 ° C. to 250 ° C., for a time sufficient to form the desired product. it can. In a continuous process, this time can vary considerably, but is typically a 0.1 to 8 hr ^-1 weight space velocity (WHSV) for olefins. As used herein, the weight hourly space velocity of a component means a value obtained by dividing the weight flow rate of the component per hour by the catalyst weight of the same unit of measurement. In particular, the alkylation of benzene with ethylene can be carried out at a temperature of 150 ° C. to 250 ° C., and the alkylation of benzene with propylene can be carried out at a temperature of 90 ° C. to 200 ° C. The ratio of alkylatable aromatics to olefins used in this process is determined by the desired degree of monoalkylation and the relative costs of the aromatic and olefinic components of the reaction mixture. For the alkylation of benzene with propylene, the benzene / olefin molar ratio can be as low as 0.1 and as high as 10, with a ratio of 0.5-3 being preferred. When alkylating benzene with ethylene, the benzene / olefin ratio is between 0.1 and 10, with a ratio of 0.5 to 4 being preferred. For olefins in the C ₆ -C ₂₀ detergent range, a benzene / olefin ratio of between 5 and 30 is generally sufficient to obtain the desired monoalkylation yield, and a range of 8 to 20 is even more preferable.

  [0038] Alkylation reaction zones often give a wide range of secondary by-products. For example, in the alkylation of benzene with ethylene to produce ethylbenzene, di- and triethylbenzene may be produced in the reaction zone in addition to other ethylene condensation products. Similarly, in the alkylation of benzene with propylene to produce cumene, di- and triisopropylbenzene may be produced in the reaction zone in addition to more condensation products. As is well known in the art, these polyalkylated aromatic compounds can be contacted with additional aromatic bases in the transalkylation zone to produce additional monoalkylated products. See for example US-7,622,622 and US-7,268,267. Furthermore, since a transalkylation reaction takes place in the alkylation reaction zone and an alkylation reaction takes place in the transalkylation reaction zone, any zone can be referred to as an alkylation zone. Thus, the term “alkylation zone” as used herein includes transalkylation zone. In one aspect, the alkylated benzene product comprises at least one of ethylene benzene and cumene.

  [0039] In a further aspect, the present invention is a method of making an alkylated benzene compound. The method includes contacting a hydrocarbon feed stream comprising benzene, an organic nitrogen compound, and a diolefin compound with one of an adsorbent comprising clay, acidic molecular sieve, and activated carbon. In some cases, the diolefin compound has 4 to 6 carbon atoms per molecule. The contact conditions include a temperature of at least 50 ° C. when using clay adsorbent or activated carbon, and a temperature of at least 25 ° C. when using acidic molecular sieves, and water in an amount of at least 50 ppm based on the weight of the hydrocarbon feed. Including the presence of In the contacting step, the diolefin compound is removed, producing a treated hydrocarbon stream having a lower diolefin compound concentration than the hydrocarbon feed stream. At least a portion of the treated hydrocarbon stream is sent to a nitrogen removal zone where organic nitrogen compounds are removed to produce an alkylated base stream having a lower concentration of organic nitrogen compounds compared to the treated hydrocarbon stream. At least a portion of the alkylated base stream is sent to the alkylation zone where the portion of the alkylated base stream and the alkylating agent are contacted with an alkylation catalyst to produce an alkylated benzene compound. In one embodiment, the alkylated benzene compound is a monoalkylated benzene compound, which may include at least one of ethylbenzene and cumene.

Example 1:
[0040] According to one approach, the adsorbent for use in accordance with the present invention is a commercially available acid-treated clay obtained from Sud-Chemie under the trade name TONSIL CO 630G.

Example 2:
[0041] According to another approach, commercially available activated carbon was obtained from Calgon.
Example 3:
[0042] According to another approach, a sample of steam modified ammonium ion-exchange Y-zeolite was slurried in 15 wt% of NH ₄ NO ₃ aqueous solution, the temperature of the solution was 75 ℃ (167 ° F). Steam-modified ammonium ion-exchanged Y zeolite is a stable having a bulk Si / Al ₂ ratio of 5.2, a unit cell size of 24.53, and a sodium content of 2.7% by weight calculated as Na ₂ O on a dry basis. Sodium fluoride Y zeolite. Steam-modified ammonium ion exchange Y zeolite is a sodium having a bulk Si / Al ₂ ratio of 4.9, a unit cell size of 24.67, and a sodium content of 9.4% by weight calculated as Na ₂ O on a dry basis. Prepared from Y zeolite, which is exchanged with ammonium to remove 75% of Na, then the steps of the procedure described in US Pat. No. 5,324,877, column 4, line 47 to column 5, line 2 (1 ) And (2) followed by steam dealumination at 600 ° C. (1112 ° F.). After 1 hour of contact at 75 ° C. (167 ° F.), the slurry was filtered and the filter cake was washed with an excess of warm deionized water. These NH ₄ ⁺ ion exchange, filtration, and water washing steps were repeated two more times, and the resulting filter cake was calculated as Na ₂ O on a dry Si basis with a bulk Si / Al ₂ ratio of 5.2. It had a sodium content of 0.13% by weight, a unit cell size of 24.572 kg, and an absolute intensity of 96 as measured by X-ray diffraction. The resulting filter cake is dried to a suitable moisture level and mixed with HNO ₃ peptized Pural SB alumina to give a mixture of 80 parts by weight zeolite and 20 parts by weight Al ₂ O ₃ binder on a dry basis, Next, it was extruded into a cylindrical extrudate having a diameter of 1.6 mm. The extrudate was dried and calcined at 600 ° C. for 1 hour in an air stream to give a unit cell size of 24.494 kg, an XRD absolute strength of 61.1, and 57.2% as a percent of aluminum in the modified Y zeolite. A control zeolite adsorbent with framework aluminum was obtained.

Example 4:
[0043] A sample of an industrial benzene recycle stream (> 99 wt% benzene) containing olefins, diolefins, and nitrogen compounds was used as a hydrocarbon feed stream without drying or other treatment. The effectiveness of the adsorbents of Examples 1-3 to remove unsaturated aliphatic compounds was evaluated. The feed stream analysis is reported in Table 1 along with the effluent or product analysis from each test. The unsaturated aliphatic content was determined by the bromine index method UOP304. The diolefin content was determined by UOP980 modified to improve the sensitivity of the method to detect lower levels of diolefin. UOP 980 was followed, except that the sample size was changed and a lower concentration standard solution was used during instrument calibration as known to those skilled in the art to improve detection of lower concentrations of diolefins in the sample. The modification of UOP 980 does not change the relative measurement between different samples, but improves and / or enables the quantification of diolefin concentrations below 500 ppmw, in particular below 100 ppmw. The industrial benzene recycle stream also contained water near the saturation level, so the contact conditions included an amount of water in the range of 600 ppm to 800 ppm relative to the hydrocarbon feed stream on a weight basis.

  [0044] Prior to testing, the adsorbent was pre-dried for 4 hours at 250 ° C. in a stream of nitrogen. The adsorption experiment was performed in an autoclave first purged with nitrogen and then filled with 0.6 g adsorbent and 30 g hydrocarbon feed. The autoclave was then pressurized to 400 psig and raised to the temperature listed in Table 1 for each test. The autoclave includes a mixer set at 100 rpm. When the indicated temperature was reached, the autoclave was maintained at that temperature for 1 hour with mixing. Thereafter, heating was stopped, the autoclave was cooled to room temperature, and mixing was stopped. The spent adsorbent was separated from the liquid product or effluent, sampled and analyzed.

  [0045] The data show that each material of Examples 1-3 is effective in removing unsaturated aliphatic compounds as measured by the bromine index and in removing diolefins. . The clay adsorbent of Example 1 according to the present invention showed unexpected selectivity and stability in diolefin removal. At each of the temperatures evaluated, the clay adsorbent showed much greater diolefin removal compared to unsaturated aliphatic removal, and therefore higher diolefin removal relative to the general class of unsaturated aliphatic compounds. The selectivity for removal was shown. Surprisingly, the amount of diolefin removed by the clay adsorbent of Example 1 was not significantly affected over the entire temperature range evaluated. The activated carbon of Example 2 according to the present invention showed selectivity for the removal of unsaturated aliphatic hydrocarbons equivalent to the removal of diolefin, with higher amounts being removed at higher contact temperatures. The acidic molecular sieve of Example 3 according to the present invention showed selectivity for the removal of unsaturated aliphatic hydrocarbons equivalent to the removal of diolefin, with higher amounts being removed at higher contact temperatures.

Claims (10)

  An adsorbent comprising clay, acidic molecular sieves, and activated carbon under a contact condition comprising the hydrocarbon feed stream at a temperature of at least 25 ° C. and the presence of water in an amount of at least 50 ppm relative to the hydrocarbon feed stream on a weight basis. Of treating a hydrocarbon feed stream comprising an aromatic compound, a nitrogen compound, and an unsaturated aliphatic compound comprising contacting one of the two to remove an unsaturated aliphatic compound to produce a treated hydrocarbon stream .   The process of claim 1 wherein water is present in an amount equal to or greater than the saturation point of the hydrocarbon feed stream at the contact conditions.   The process of claim 1, wherein the water is present in an amount of at least 250 ppm based on the weight of the hydrocarbon feed.   The method of claim 1, wherein contacting the hydrocarbon feed comprises contacting the hydrocarbon feed with a clay adsorbent and the temperature is in the range of 50 ° C. to 300 ° C.   The method of claim 1, wherein contacting the hydrocarbon feed comprises contacting the hydrocarbon feed with an acidic molecular sieve and the temperature is in the range of 45-115C.   The method of claim 1, wherein contacting the hydrocarbon feed stream comprises contacting the hydrocarbon feed stream with activated carbon, wherein the temperature ranges from 100 ° C. to 300 ° C.   The process of claim 1 wherein the hydrocarbon feed stream has a nitrogen content in the range of 1 ppmw to 10 ppmw.   The method of claim 1, wherein the nitrogen compound is an organic nitrogen compound selected from the group consisting of a basic organic nitrogen compound, a nitrile, and mixtures thereof.   The process according to claim 1, wherein the unsaturated aliphatic compound is a diolefin compound.   The method of claim 9, wherein the diolefin compound is selected from the group consisting of butadiene, pentadiene, methylbutadiene, hexadiene, methylpentadiene, dimethylbutadiene, acetylene, and mixtures thereof.