CN103261128A - Process for removing unsaturated aliphatic hydrocarbons from hydrocarbon streams using clays - Google Patents

Abstract

A process for removing unsaturated aliphatic compounds from a hydrocarbon feed stream by contacting the hydrocarbon feed stream with one of an adsorbent comprising clay, an acidic molecular sieve, and activated carbon to produce a hydrocarbon effluent stream having a lower unsaturated aliphatic content relative to the hydrocarbon feed stream. The hydrocarbon feed stream comprises aromatic compounds, nitrogen compounds, and unsaturated aliphatic compounds.

Description

Process for removing unsaturated aliphatic hydrocarbons from hydrocarbon streams using clays

priority statement

This application claims the benefit of priority to US Provisional Application Nos. 61/424,813, 61/424,822, and 61/424,831, all filed on December 20, 2010.

The technical field to which the invention belongs

The present invention relates to a process for removing unsaturated aliphatic compounds from a hydrocarbon stream. More particularly, the present invention relates to the removal of unsaturated aliphatic compounds from hydrocarbon streams that include aromatic compounds.

current technology

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 considerable commercial interest include the alkylation of aromatic compounds (for example in the production of ethyltoluene, xylene, ethylbenzene, cumene or higher alkylaromatic compounds and for example Disproportionation reactions such as toluene disproportionation), isomerization of xylene or transalkylation of polyalkylbenzene to monoalkylbenzene. The feedstock for this aromatic conversion process will often comprise an aromatic component (ie, an alkylation substrate, such as benzene) and a C2 to C20 olefin alkylating agent or a polyalkylaromatic hydrocarbon transalkylating agent. As used herein, terms such as "C4", "C5", "C6", etc. indicate the number of carbon atoms per molecule of hydrocarbon or hydrocarbon species. In the alkylation zone, an aromatic feed stream and an olefinic feed stream can react over an alkylation catalyst to produce an alkylated aromatic compound, such as cumene or ethylbenzene. Part or all of the alkylation substrate may be provided by other process units comprising the separation section of the styrene process unit. Polyalkylated benzene is separated from the monoalkylated benzene product and recycled to the transalkylation zone and contacted with benzene over a transalkylation catalyst to produce monoalkylated benzene and benzene.

Catalysts used in aromatic conversion processes typically include zeolite molecular sieves. Examples include Zeolite Beta (US 4,891,458); Zeolite Y, Zeolite Omega, and Zeolite Beta (US 5,030,786); X, Y, L, B, ZSM-5, and Omega crystal types (US 4,185,040); X, Y, Ultra Stabilized Y, L, omega, and mordenite zeolite (US4,774,377); and UZM-8 zeolite (US6,756,030 and US7,091,390). It is known in the art that aromatic feed streams for aromatic conversion processes often contain nitrogen compounds (including weakly basic organic nitrogen compounds such as nitriles) that can cumulatively degrade downstream aromatic conversions even at ppm and ppb concentrations Catalysts, such as aromatic alkylation catalysts, are poisoned and their service life is significantly shortened. Various guard beds with clay, zeolite or resin adsorbents are known in the art to remove one or more types of nitrogen compounds from aromatic hydrocarbon streams upstream of aromatic conversion processes. Examples include: US7,205,448, US7,744,828, US6,297,417, US5,220,099, WO00/35836, WO01/07383, US4,846,962, US6,019,887 and US6,107,535.

It has recently been found that unsaturated aliphatic hydrocarbons (such as olefinic compounds and dienes in particular) can shorten the effective life of adsorbents (such as nitrogen-adsorbing zeolites or molecular sieves) used in nitrogen guard beds used in various Process streams, including aromatic hydrocarbon feed upstream of an aromatic conversion process such as alkylation. These unsaturated aliphatic (e.g., olefinic) compounds are present in aromatic process streams contaminated with nitrogen compounds, including benzene streams produced in the separation section of the styrene process and required in combination with catalysts prone to nitrogen poisoning or Other streams of nitrogen compounds are removed prior to other material contact. In particular, the presence of highly unsaturated olefinic compounds (eg, C4-C6 dienes) in aromatic streams with nitrogen compound contaminants adversely affects the performance of nitrogen adsorbent materials. Without wishing to be bound by theory, it is believed that olefinic and/or other unsaturated aliphatic compounds can shorten the lifetime of nitrogen adsorbents by competing with nitrogen compounds for adsorption sites and/or by interacting with, for example, aromatic compounds such as benzene) to form heavy reaction products that deposit on the nitrogen guard bed adsorbent.

Brief description of the invention

The present invention relates to a process for removing unsaturated aliphatic compounds, including olefins and/or dienes, present in an aromatic hydrocarbon stream. In one embodiment, the present invention allows for longer life of the sorbent in the downstream nitrogen removal zone, which minimizes the need to regenerate or replace the nitrogen sorbent.

In one embodiment, the invention is a process for treating a hydrocarbon feed stream comprising aromatic compounds, nitrogen compounds, and unsaturated aliphatic compounds. In one form, the process comprises contacting a hydrocarbon feed stream with an adsorbent comprising clay to remove unsaturated aliphatic compounds and produce a treated hydrocarbon stream under contacting conditions comprising a temperature of at least 50°C and water is present in an amount of at least 50 ppm by weight relative to the hydrocarbon feed stream. In another form, the process comprises contacting a hydrocarbon feed stream with an acidic molecular sieve to remove unsaturated aliphatic compounds and produce a treated hydrocarbon stream under contacting conditions comprising a temperature of at least 25°C and the presence of a relative Water in an amount of at least 50 ppm by weight in the hydrocarbon feed stream. In yet another form, the process comprises contacting a hydrocarbon feed stream with activated carbon to remove unsaturated aliphatic compounds and produce a treated hydrocarbon stream under contacting conditions comprising a temperature of at least 50°C and the presence of relative Water in an amount of at least 50 ppm by weight in the hydrocarbon feed stream.

In another embodiment, the invention is a method for producing an alkylated benzene compound. The process comprises (i) contacting a hydrocarbon feed stream comprising benzene, an organic nitrogen compound, and a diene compound with one of an adsorbent comprising clay, an acidic molecular sieve, and activated carbon to remove the diene compound and produce a treated a hydrocarbon stream; (ii) sending at least a portion of the treated hydrocarbon stream to a nitrogen removal zone, which produces an alkylation substrate stream; and (iii) sending at least a portion of the alkylation substrate stream to an alkylation zone , which produces an alkylated benzene compound.

The combination of removing one or more unsaturated aliphatic compounds and removing nitrogen from the aromatic stream can prolong the life of the catalyst in the alkylation zone and/or the life of the adsorbent in the nitrogen removal zone, which removes A zone may be located between the unsaturated aliphatic removal zone and the alkylation zone. Additionally, the removal of reactive unsaturated aliphatic hydrocarbons such as olefins and/or dienes can minimize the loss of benzene and other desired aromatics to be recycled and reacted. Surprisingly, it has been found that adsorbents comprising clay are more selective for removing dienes having 4 to 6 carbon atoms per molecule than the bulk mixture of unsaturated aliphatic hydrocarbons in a hydrocarbon feed stream.

Detailed description of the invention

The present invention relates to a process for treating a hydrocarbon feed stream wherein one or more unsaturated aliphatic hydrocarbon compounds are removed from the feed stream by one of an adsorbent comprising clay, an acidic molecular sieve, and activated carbon to produce a treated hydrocarbon material flow. The treated hydrocarbon stream has a lower unsaturated aliphatic hydrocarbon content relative to the hydrocarbon feed stream. The hydrocarbon feed stream of the present invention comprises aromatic compounds, nitrogen compounds and unsaturated aliphatic compounds.

The aromatic hydrocarbon compound may be selected from the group consisting of benzene, naphthalene, anthracene, phenanthrene and their substituted derivatives, wherein benzene and its derivatives are preferred aromatic compounds. The aromatic compound may have one or more substituents selected from the group consisting of alkyl groups having 1 to 20 carbon atoms, hydroxyl groups and alkoxy groups (the alkyl groups of which also contain 1 to up to 20 carbon atoms). In the case of alkyl or alkoxy substituents, phenyl may also be substituted on the alkyl chain.

Although unsubstituted and monosubstituted benzenes, naphthalene, anthracene, and phenanthrene are most commonly used in the practice of this invention, polysubstituted aromatic compounds may also be employed. Examples of suitable alkylatable aromatic compounds other than those given above include biphenyl, toluene, xylene, ethylbenzene, propylbenzene, butylbenzene, pentylbenzene, hexylbenzene, heptylbenzene, octylbenzene, etc. ; Phenol, cresol, anisole, ethoxybenzene, propoxybenzene, butoxybenzene, pentoxybenzene, hexyloxybenzene, etc. Sources of benzene, toluene, xylenes, and/or other feed aromatics include product streams from naphtha reforming units, aromatic extraction units, recycle streams from styrene monomer production units, and for Production of petrochemical complexes of p-xylene and other aromatic compounds. The hydrocarbon feed stream may contain one or more aromatic hydrocarbon compounds. In one embodiment, the concentration of aromatics in the hydrocarbon feed stream ranges from 5 wt% to 99.9 wt% of the hydrocarbon feed. In another embodiment, the hydrocarbon feedstream comprises between 50 wt% and 99.9 wt% aromatics, and may comprise between 90 wt% and 99.9 wt% aromatics.

The hydrocarbon feed stream nitrogen compounds may comprise one or more organic nitrogen compounds. Organic nitrogen compounds usually contain a large proportion of basic nitrogen compounds such as indole, pyridine, quinoline, diethanolamine (DEA), morpholine including N-formyl-morpholine (NFM), and N-methyl-pyrrolidone (NMP). Organic nitrogen compounds may also include weakly basic nitriles, such as acetonitrile, propionitrile, and acrylonitrile. As discussed below, the present invention does not necessarily require but encompasses the use of an optional nitrogen removal zone to reduce the nitrogen content of the hydrocarbon stream.

In one embodiment, the nitrogen content of the hydrocarbon feed stream ranges from 1 ppm-wt to 10 ppm-wt. In another embodiment, the concentration of the organic nitrogen compound in the hydrocarbon feed ranges from 30 ppb-wt (parts per billion by weight) to 1 mole percent of the hydrocarbon feed; the concentration of the organic nitrogen compound can be between In the range of 100 ppb-wt to 100 ppm-wt (parts by weight) of the feed. In one embodiment, the concentration of weakly basic organic nitrogen compounds (eg, nitriles) in the hydrocarbon feed ranges from 30 ppb-wt to 100 ppm-wt of the hydrocarbon feed.

The hydrocarbon feed stream comprises one or more unsaturated aliphatic compounds, including unsaturated cyclic hydrocarbons and linear and branched olefinic hydrocarbons (olefins) having one or more double bonds. Thus, as used herein, the terms "olefin" and "alkene" include diene compounds. In one embodiment, the unsaturated aliphatic compound is an olefinic compound, and the unsaturated aliphatic compound may be a diene compound. In one embodiment, the unsaturated aliphatic compound is one or more diene compounds having 4, 5 or 6 carbon atoms per molecule, i.e. the unsaturated aliphatic compound may be selected from the group consisting of C4 dienes, C5 dienes, A group of dienes composed of C6 dienes and mixtures thereof. In another embodiment, the diene compound is selected from the group consisting of butadiene, pentadiene, methylbutadiene, hexadiene, methylpentadiene, dimethylbutadiene, acetylene and its mixture.

In one embodiment, the concentration of the diene compound in the hydrocarbon feed ranges from 30 ppb-wt to 3000 ppm-wt of the hydrocarbon feed; and the concentration of the diene compound may range from 50 ppb-wt to 2000 ppm-wt of the hydrocarbon feed wt range. The hydrocarbon feed stream may include other olefins, such as mono-olefins. Typically, the total concentration of all olefins in the hydrocarbon feed stream is not greater than 1.0 wt-% olefins.

In one embodiment, the aromatic compound includes benzene, the nitrogen compound includes an organic nitrogen compound, and the unsaturated aliphatic compound includes an olefinic compound. In another embodiment, the aromatic compound includes benzene, the nitrogen compound includes an organic nitrogen compound, and the unsaturated aliphatic compound includes a diene compound, optionally the diene compound has 4 to 6 carbon atoms per molecule.

In one mode, 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 the F series adsorbents available from BASF and the TONSIL adsorbents available from SudChemie such as CO630G and CO616GS. In one embodiment, the clay adsorbent is acid activated bentonite and/or montmorillonite clay.

In another mode, the method includes the use of activated carbon. Activated carbon is well known in the art and can be derived from various sources including petroleum coke, coal, wood, and shells such as coconut shells using carbonization and/or activation process steps. Activation can be accomplished, for example, by thermal treatment in an atmosphere of _CO2 , _H2O , and mixtures thereof, by chemical treatment steps, and combinations thereof. Suitable activated carbons are commercially available and can be obtained, for example, from Calgon.

In yet another approach, the process includes using an acidic molecular sieve to adsorb or otherwise remove unsaturated aliphatic compounds from the hydrocarbon feed stream. Suitable acidic molecular sieves include the various forms of silicoaluminophosphates and aluminophosphates and zeolite molecular sieves disclosed in US 4,440,871 , US 4,310,440 and US 4,567,029. As used herein, the term "molecular sieve" is defined as a class of adsorptive desiccants having a highly crystalline nature and crystallographically defined microporosity or channels, distinct from materials such as gamma-alumina. A preferred type of molecular sieve in such crystalline adsorbents is the aluminosilicate material commonly known as zeolite. The term "zeolite" generally refers to a group of naturally occurring or synthetic hydrated metalloaluminosilicates, many of which have a crystalline structure. Zeolite molecular sieves in calcined form can be represented by the general formula:

Me _2/n O: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 valency of the cation and y has a value from 2 to 10. Typical well-known zeolites that can be used include chabazite (also known as zeolite D), clinoptilolite, erionite, faujasite, zeolite beta (BEA), zeolite omega, zeolite X, zeolite Y, MFI as mentioned below. Zeolite, zeolite MCM-22 (MWW), ferrierite, mordenite, zeolite A, zeolite P and UZM-8 type zeolite. A detailed description of some of the zeolites identified above can be found in D.W. Breck, ZEOLITE MOLECULAR SIEVES, John Wiley and Sons, New York, 1974.

Significant differences exist between various synthetic and natural materials in terms of chemical composition, crystal structure and physical properties such as X-ray powder diffraction patterns. Molecular sieves exist as accumulations of fine crystals or are synthesized as fine powders, and are preferably tableted or granulated for large scale adsorption applications. The granulation process is known in the art and is very satisfactory since the adsorption properties of the molecular sieves remain essentially unchanged, both in terms of selectivity and capacity. In one embodiment, the adsorbent comprises zeolite Y and/or zeolite X with an alumina or silica binder and/or zeolite beta with an alumina or silica binder. In one embodiment, the acidic molecular sieve is zeolite Y.

In one embodiment, molecular sieves will typically be used in combination with refractory inorganic oxide binders. The binder may comprise alumina or silica, with the former being preferred, and gamma-alumina, eta-aluminum, and mixtures thereof being especially preferred. The molecular sieve may be present in the range of 5 wt-% to 99 wt-% of the adsorbent and the refractory inorganic oxide may be present in the range of 1 wt-% to 95 wt-%. In one embodiment, the molecular sieve will be present in an amount of at least 50 wt-% of the adsorbent and more preferably at least 70 wt-% of the adsorbent.

The molecular sieves in the adsorbent of the present invention are acidic. Using the silicon to aluminum ratio as a gauge for the acidity level, the silicon to aluminum ratio should be no greater than 100 in one embodiment and no greater than 25 in another embodiment. Cations on molecular sieves are undesirable. Thus, in the case of zeolites Y and Beta, it may be desirable to acid wash to remove alkali metals (eg sodium) to reveal more acid sites, thereby increasing adsorption capacity. Migration of aluminum out of the matrix into the binder should also be avoided as this reduces acidity. Incorporation of cations, such as alkaline earth elements and rare earth elements, into zeolite X or Y to some extent will improve the thermal and hydrothermal stability of the framework aluminum, minimize the amount of framework aluminum migrating out of the framework, and can Obtain sites with varying acid strengths. The cation incorporation should be balanced to improve overall acidity and/or hydrothermal stability without inhibiting adsorption performance, which can occur at higher cation incorporation. 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, when the alkylation catalyst is more expensive than the molecular sieve adsorbent, the composition of the alkylation catalyst and molecular sieve is preferably different.

The hydrocarbon feed stream to be treated is contacted with one of a clay adsorbent, an acidic molecular sieve, and activated carbon under contacting conditions to remove one or more unsaturated aliphatic compounds and produce a treated hydrocarbon stream. Unsaturated aliphatic compounds can be removed from hydrocarbon streams by various mechanisms, such as adsorption with a sorbent, reaction with a sorbent, and reactive adsorption. The unsaturated aliphatic compound content of the treated hydrocarbon stream is reduced relative to the unsaturated aliphatic compound content of the hydrocarbon feed stream.

Contacting conditions include a temperature of at least 50°C in the case of clay adsorbent or activated carbon, and a temperature of at least 25°C in the case of acidic molecular sieves, and in an amount of at least 50 ppm by weight relative to the hydrocarbon feed stream carried out in the presence of water. Water may be present in an amount equal to or exceeding the saturation point of the hydrocarbon feed stream under the contacting conditions. In one embodiment, the water is present in an amount of at least 250 ppm by weight relative to the hydrocarbon feed stream. In another embodiment, water is present in an amount ranging from 300 ppm to 800 ppm by weight relative to the hydrocarbon feed stream, and water may be present in an amount ranging from 450 ppm to 700 ppm by weight relative to the hydrocarbon feed stream Quantity exists. The amount of water during contacting can be controlled in any suitable manner. For example, the water content of a hydrocarbon feed can be monitored and controlled by drying the feed stream and/or adding water or water-generating compounds to the feed stream. Water or a water-forming compound can be introduced to the contacting step as a separate stream, and the feed stream can be dried to a consistent water content while the water or water-forming compound is added to achieve the desired level.

In the mode using clay adsorbent, the contacting temperature is in the range of 50°C to 300°C and the contacting temperature may be in the range of 50°C to 125°C. In another embodiment, the contacting temperature ranges from 75°C to 250°C; and the contacting temperature may range from 100°C to 225°C. In the approach using activated carbon to contact the hydrocarbon stream, the contacting temperature is in the range of 100°C to 300°C. In another embodiment, the contacting temperature is in the range of 125°C to 300°C; and the contacting temperature may be in the range of 150°C to 300°C. In yet another approach in which the hydrocarbon stream is contacted with the acidic molecular sieve, the contacting temperature is in the range of 25°C to 300°C and the contacting temperature may be in the range of 45°C to 115°C. In another embodiment, the contacting temperature is in the range of 45°C to 110°C; and the contacting temperature may be in the range of 50°C to 110°C.

In embodiments where a clay sorbent is used to contact the hydrocarbon stream, the amount of water is at least 50 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature is: (i) at least 50°C; (ii) between 50°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 embodiment, the amount of water is at least 250 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature: (i) is at least 50°C; (ii) is 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 another embodiment, the amount of water equals or exceeds the saturation point of the hydrocarbon feed stream under the contacting conditions, and the contacting temperature: (i) is at least 50°C; (ii) is 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 another embodiment, the amount of water ranges from 300 ppm to 800 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature is: (i) at least 50°C; (ii) between 50°C and 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 embodiment, the amount of water ranges from 450 ppm to 700 ppm by weight relative to the hydrocarbon feed stream and the contacting temperature: (i) is at least 50°C; (ii) ranges from 50°C to 300°C (iii) within the range of 50°C to 125°C; (iv) within the range of 75°C to 250°C; or (v) within the range of 100°C to 225°C. Optionally, the contacting conditions may additionally comprise a pressure of 34.5 kPa(g) to 4136.9 kPa(g). In one embodiment, the contacting is performed using a feed that is in a liquid phase or a partially liquid phase. Gas phase contacting can be used.

In another embodiment using activated carbon for contacting a hydrocarbon stream, the amount of water is at least 50 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature is: (i) at least 50°C; (ii) between 100°C to within the range of 300°C; (iii) within the range of 125°C to 300°C; or (iv) within the range of 150°C to 300°C. In one embodiment, the amount of water is at least 250 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature: (i) is at least 50°C; (ii) is 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 another embodiment, the amount of water is equal to or exceeds the saturation point of the hydrocarbon feed stream under the contacting conditions, and the contacting temperature: (i) is at least 50°C; (ii) is 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 another embodiment, the amount of water ranges from 300 ppm to 800 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature is: (i) at least 50°C; (ii) between 100°C and 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 embodiment, the amount of water is in the range of 450 ppm to 700 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature: (i) is at least 50°C; (ii) is in the range of 100°C to 300°C (iii) within the range of 125°C to 300°C; or (iv) within the range of 150°C to 300°C. Optionally, the contacting conditions may additionally comprise a pressure of 34.5 kPa(g) to 4136.9 kPa(g). In one embodiment, the contacting is performed using a feed that is in a liquid phase or a partially liquid phase. Gas phase contacting can be used.

In another embodiment using an acidic molecular sieve for contacting a hydrocarbon stream, the amount of water is at least 50 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature is: (i) at least 25°C; (ii) between 25°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 embodiment, the amount of water is at least 250 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature: (i) is at least 25°C; (ii) is 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 another embodiment, the amount of water is equal to or exceeds the saturation point of the hydrocarbon feed stream under the contacting conditions, and the contacting temperature: (i) is at least 25°C; (ii) is 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 another embodiment, the amount of water ranges from 300 ppm to 800 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature is: (i) at least 25°C; (ii) between 25°C and 300°C (iii) within the range of 45°C to 115°C; (iv) within the range of 45°C to 110°C; or (v) within the range of 50°C to 110°C. In one embodiment, the amount of water ranges from 450 ppm to 700 ppm by weight relative to the hydrocarbon feed stream, and the contacting temperature: (i) is at least 25°C; (ii) ranges from 25°C to 300°C (iii) within the range of 45°C to 115°C; (iv) within the range of 45°C to 110°C; or (v) within the range of 50°C to 110°C. Optionally, the contacting conditions may additionally comprise a pressure of 34.5 kPa(g) to 4136.9 kPa(g). In one embodiment, the contacting is performed using a feed that is in a liquid phase or a partially liquid phase. Gas phase contacting can be used.

The bromine index is commonly used to assess the unsaturated aliphatic (including olefins and dienes) content of hydrocarbon mixtures. In one embodiment, the present invention removes at least 50% of the unsaturated aliphatic compounds from the hydrocarbon feed stream. That is, in this embodiment, the bromine index of the treated hydrocarbon stream is at most 50% of the bromine index of the hydrocarbon feed stream. As used herein, the bromine index of a hydrocarbon stream or mixture is determined using method UOP304. In embodiments utilizing a clay sorbent to contact a hydrocarbon stream, the present invention removes at least 70 wt% of diene compounds from the hydrocarbon feed stream; and the present invention may remove at least 90 wt%, or at least 95 wt% of diene compounds from the hydrocarbon feed stream diene compounds. In another embodiment using activated carbon to contact a hydrocarbon stream, the present invention removes at least 30 wt% of diene compounds from the hydrocarbon feed stream; and the present invention can remove at least 50 wt% or at least 80 wt% from the hydrocarbon feed stream diene compounds. In another embodiment using an acidic molecular sieve to contact a hydrocarbon stream, the present invention removes at least 50 wt% of diene compounds from the hydrocarbon feed stream; and the present invention may remove at least 70 wt% or at least 85 wt% from the hydrocarbon feed stream Or at least 90 wt% diene compounds. Herein, the diene content of a hydrocarbon stream or mixture is determined by method UOP980. Analytical methods used herein (eg, UOP304 and UOP980) were obtained from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA, USA, unless otherwise indicated.

In another embodiment, the present invention additionally comprises passing at least a portion of the treated hydrocarbon stream to a nitrogen removal zone which produces an alkylate base material having a lower concentration of nitrogen compounds relative to the treated hydrocarbon stream flow. As discussed above, various methods for removing nitrogen compounds from aromatic hydrocarbon streams are well known in the art. See, eg, US7,205,448, US7,744,828, US6,297,417; each of which is incorporated herein by reference in its entirety. Briefly, the treated hydrocarbon stream is introduced into a nitrogen removal zone comprising at least one adsorbent effective to remove nitrogen. Suitable adsorbents include clays, resins and zeolites. Typically, clay and zeolite adsorbents are acidic. The nitrogen removal zone may comprise two adsorbents, such as a clay or resin adsorbent, located upstream of the zeolite adsorbent such that the treated hydrocarbon stream first contacts the clay or resin adsorbent to produce an intermediate stream which then contacts the zeolite adsorbent. Different operating conditions including temperature and the amount of water present have been disclosed for different adsorbents and where multiple adsorbents are used in the nitrogen removal zone.

In one embodiment, the treated hydrocarbon stream is contacted with an adsorbent comprising an acidic molecular sieve under nitrogen removal conditions to produce an alkylation substrate stream having a reduced nitrogen content. In one embodiment, the molecular sieve is a zeolite. Well-known zeolites that may be used include chabazite (also known as zeolite D), clinoptilolite, erionite, faujasite, zeolite beta (BEA), zeolite omega, zeolite X, zeolite Y, MFI zeolite, Zeolite MCM-22 (MWW), ferrierite, mordenite, zeolite A, zeolite P and UZM-8 type zeolite. In one embodiment, the nitrogen removal conditions include a temperature ranging from at least 120°C to 300°C, and the presence of water in an amount ranging from 20 ppm to 500 ppm by weight relative to the treated hydrocarbon stream.

In another embodiment, the present invention additionally comprises passing at least a portion of the alkylation substrate stream from the nitrogen removal zone to an alkylation zone, wherein the portion of the alkylation substrate stream and the alkylating agent are combined with an alkane The alkylation catalyst is contacted to produce an alkylated benzene product.

In the selective alkylation of aromatics with an olefinic alkylating agent catalyzed by an acidic catalyst, the olefin may contain from 2 to at least 20 carbon atoms and may be branched or linear, terminal or internal olefins. Therefore, the specific nature of the alkene is not particularly important. A common feature of the alkylation reactions is that the reactions are carried out under at least partial liquid phase conditions (a criterion readily achievable for lower carbon members by adjusting the reaction pressure). Among light olefins, ethylene and propylene are the most important representatives. The olefinic feed stream comprising the alkylating agent may comprise ethylene and/or propylene. Typically, the olefinic feedstream comprising propylene can be at least 65 wt% pure and the olefinic feedstream comprising ethylene can be more than 80 wt% pure. Among the remaining olefins, detergent range olefins consisting of linear olefins having 6 to 20 carbon atoms having internal or terminal unsaturation are particularly advantageous. Linear olefins containing from 8 to 16 carbon atoms and especially those containing from 10 to up to 14 carbon atoms are particularly useful as detergent range olefins. The alkylating agent may also be provided by the alkyl content of the polyalkylated benzene in the transalkylation reaction zone. Diethylbenzene, triethylbenzene, and diisopropylbenzene are prominent examples of polyalkylated benzenes that can provide these alkylating agents.

A variety of catalysts can be used in the alkylation reaction zone. Suitable catalysts for use in the alkylation zone include catalysts that do not suffer from the deleterious effects of the water present. Preferably, substantial amounts of water are tolerated or desired in the presence of the alkylation catalyst. A substantial amount of water preferably means a concentration of water in the reactants entering the alkylation zone of at least 50 wppm. The water content of the alkylation reaction zone can range from as little as 20 wppm to over 200 wppm and up to as high as 1000 wppm or more. Preferred catalysts for use in the present invention are zeolite catalysts. The catalysts of the present invention are typically used in combination with refractory inorganic oxide binders. Preferred binders are alumina or silica. Suitable zeolites include zeolite beta as described in US 5,723,710, ZSM-5, PSH-3, MCM-22, MCM-36, MCM-49, MCM-56, Y-type zeolite and UZM-8, which UZM-8 includes Aluminosilicate and substituted aluminosilicate zeolites described in US 6,756,030 and modified UZM-8 zeolites such as UZM-8HS described in US 7,091,390. Each of US6,756,030 and US7,091,390 are hereby incorporated by reference in their entirety.

The basic configuration of catalytic aromatic alkylation zones is known in the art. The feed aromatic alkylation substrate and feed olefin alkylating agent are preheated and loaded into typically 1 to 4 reactors in series. Suitable cooling means may be provided between the reactors to compensate for the net exotherm of reaction in each reactor. Suitable means may be provided upstream of or to each reactor to feed additional aromatics, olefins or other streams (such as reactor effluents or containing one or more A stream of polyalkylbenzenes) is loaded into any reactor in the alkylation zone. Each alkylation reactor may contain one or more beds of alkylation catalyst. The present invention encompasses two-zone aromatic alkylation processes such as those set forth in US 7,420,098, which is hereby incorporated by reference in its entirety.

The specific conditions for carrying out the alkylation reaction depend on the aromatic compound and olefin used. A necessary condition is to carry out the reaction under at least partially liquid phase conditions. Accordingly, the reaction pressure is adjusted to maintain at least partial dissolution of the olefin in the liquid phase. For higher olefins, the reaction can be carried out under autogenous pressure. Alkylation conditions typically involve pressures in the range between 1379 kPa(g) and 6985 kPa(g). In one embodiment, the pressure ranges between 2069 kPa(g) and 4137 kPa(g). Alkylation of aromatics with olefins in the C2 to C20 range can be carried out at a temperature of 60°C to 400°C, and preferably 90°C to 250°C for a time sufficient to form the desired product. In continuous processes, this time can vary considerably, but typically ranges from 0.1 hr ⁻¹ to 8 hr ⁻¹ weight hourly space velocity (WHSV) for olefins. As used herein, the weight hourly space velocity of a component means the weight flow rate of the component per hour divided by the catalyst weight in 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 aromatic compound to olefin used in the process of the invention depends on the degree of monoalkylation desired and the relative costs of the aromatic and olefinic components of the reaction mixture. For alkylation of benzene with propylene, the molar ratio of benzene to olefin can be as low as 0.1 and as high as 10, with a ratio of 0.5 to 3 being preferred. If the benzene is alkylated with ethylene, the ratio of benzene to olefin can be between 0.1 and 10, with a ratio of 0.5 to 4 being preferred. For C6 to C20 detergent range olefins, a benzene to olefin ratio between 5 and 30 is generally sufficient to obtain the desired monoalkylation yield, with a range between 8 and 20 being even more preferred.

The alkylation reaction zone will often provide a variety of minor by-products. For example, in the alkylation of benzene with ethylene to produce ethylbenzene, the reaction zone may produce diethylbenzene and triethylbenzene in addition to other ethylene condensation products. Similarly, in the alkylation of benzene with propylene to produce cumene, the reaction zone can also produce diisopropylbenzene and triisopropylbenzene in addition to further condensation products. These polyalkylated aromatic compounds may contact other aromatic substrates in the transalkylation zone to produce other monoalkylated products, as is well known in the art. See, eg, US 7,622,622 and US 7,268,267. Furthermore, since the transalkylation reaction occurs in the alkylation reaction zone and the alkylation reaction occurs in the transalkylation reaction zone, both zones may be referred to as the alkylation zone. Thus, as used herein, the term "alkylation zone" encompasses a transalkylation zone. In one embodiment, the alkylated benzene product comprises at least one of ethylbenzene and cumene.

In another embodiment, the invention is a method for producing an alkylated benzene compound. The process includes contacting a hydrocarbon feed stream comprising benzene, an organic nitrogen compound, and a diene compound with one of an adsorbent comprising clay, an acidic molecular sieve, and activated carbon. Optionally, the diene compound has 4 to 6 carbon atoms per molecule. Contacting conditions include a temperature of at least 50°C in the case of clay adsorbent or activated carbon and a temperature of at least 25°C in the case of acidic molecular sieves, and the presence of water in an amount of at least 50 ppm by weight relative to the hydrocarbon feed stream . The contacting step removes diene compounds and produces a treated hydrocarbon stream having a lower concentration of diene compounds than the hydrocarbon feed stream. At least a portion of the treated hydrocarbon stream is sent to a nitrogen removal zone, which removes organic nitrogen compounds and produces an alkylation substrate stream having a lower concentration of organic nitrogen compounds relative to the treated hydrocarbon stream. At least a portion of the alkylated substrate stream is sent to an alkylation zone wherein the portion of the alkylated substrate stream and an alkylating agent are contacted with an alkylation catalyst to produce an alkylated benzene compound. In one embodiment, the alkylated benzene compound is a mono-alkylated benzene compound, which may comprise at least one of ethylbenzene and cumene.

Example 1

According to one mode, the adsorbent used in the present invention is a commercially available acid-treated clay obtained from Sud-Chemie under the product name TONSIL CO630G.

Example 2

According to another approach, commercially available activated carbon is obtained from Calgon.

Example 3

且通过X射线衍射所测定的绝对强度为96。将所得滤饼干燥至适当水分含量，与经HNO₃胶溶的Pural SB氧化铝混合以得到以干重计80重量份数沸石及20重量份数Al₂O₃粘合剂的混合物，且然后将其挤出成1.6mm直径圆柱形挤出物。将挤出物干燥并在600℃下在流动空气中煅烧1小时以获得比较沸石吸附剂，其单位晶胞大小为

XRD绝对强度为61.1，且以经改性Y沸石中铝的百分比表示骨架铝为57.2%。According to another approach, a sample _of steam-modified ammonium ion-exchanged Y zeolite was slurried in 15 wt% _NH4NO3 aqueous solution and the temperature of the solution was raised to 75°C (167°F). The steam-modified ammonium ion-exchanged Y zeolite is a stabilized sodium Y zeolite with a volumetric Si/ _Al2 ratio of 5.2, a unit cell size of 24.53, and a sodium content calculated as _Na2O on a dry basis of 2.7wt%. The steam-modified ammonium ion-exchanged Y zeolite was prepared from a sodium Y zeolite with a volumetric Si/ _Al2 ratio of 4.9, a unit cell size of 24.67 and a sodium content calculated as _Na2O on a dry weight basis is 9.4 wt%, which is ammonium exchanged to remove 75% of the Na and then generally passed through the following steps (1) and ( 2) Dealuminated by steam 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 excess warm deionized water. These _NH4 + ion exchange, filtration and water washing steps were repeated 2 more times and the obtained filter cake had a volumetric Si/ _Al2 ratio of 5.2 and a sodium content of 0.13 wt% calculated as _Na2O on a dry basis, unit The unit cell size is

And the absolute intensity measured by X-ray diffraction was 96. The resulting filter cake was dried to the appropriate moisture content, mixed with _HNO3 peptized Pural SB alumina to obtain a mixture of 80 parts by weight zeolite and 20 parts by weight _Al2O3 binder on a dry weight basis, _and then This was extruded into 1.6 mm diameter cylindrical extrudates. The extrudates were dried and calcined at 600 °C in flowing air for 1 h to obtain comparative zeolite adsorbents with a unit cell size of

The XRD absolute intensity was 61.1 and the framework aluminum was 57.2% expressed as a percentage of aluminum in the modified Y zeolite.

Example 4

A sample of an industrial benzene recycle stream (>99 wt% benzene) containing olefins, dienes, and nitrogen compounds without drying or other treatment was used as the hydrocarbon feed to evaluate the removal of unsaturated lipids by the adsorbents of Examples 1-3 potency of family compounds. The analysis of the feed and analysis of the effluent or product from each test is reported in Table 1. The unsaturated aliphatic content is determined by bromine index method UOP304. Diene content was determined by UOP980 modified to improve the sensitivity of the method to detect lower levels of dienes. UOP980 was followed except for sample size changes, and as known to those skilled in the art, lower concentrations of standard solutions were used during instrument calibration to improve detection of lower concentrations of dienes in samples. The modification of UOP980 does not change the relative measurements between different samples, but improves and/or enables the quantification of dienes at concentrations less than 500 ppm-wt and especially less than 100 ppm-wt. Commercial benzene recycle streams also contain water near saturation levels, so contacting conditions include water in amounts of 600 ppm to 800 ppm by weight relative to the hydrocarbon feed stream.

Before testing, the sorbent was pre-dried in flowing nitrogen at 250 °C for 4 h. Adsorption experiments were carried out in an autoclave which was first purged with nitrogen and subsequently loaded with 0.6 g of adsorbent and 30 g of hydrocarbon feed. The autoclave was then pressurized to 400 psig and ramped to the temperature listed in Table 1 for each test. The autoclave contained a mixer set at 100 rpm. When the specified temperature was reached, the autoclave was kept at temperature for 1 hour while mixing. After this time, the heat was turned off to allow the autoclave to cool to room temperature and mixing ceased. The spent adsorbent is separated from the liquid product or effluent, which is sampled and analyzed.

Table 1

The data demonstrates that each of the materials in Examples 1-3 is effective in removing unsaturated aliphatic hydrocarbons (as determined by bromine index) and in removing diolefins. The inventive clay adsorbent of Example 1 exhibited unexpected selectivity and stability in the removal of diolefins. At each temperature evaluated, the clay sorbent exhibited significantly higher removal of dienes compared to the removal of unsaturated aliphatics, thus removing dienes relative to the general type of unsaturated aliphatics. Demonstrate greater selectivity. Surprisingly, the amount of dienes removed by the clay sorbent of Example 1 was largely unaffected over the temperature range evaluated. The inventive activated carbon of Example 2 exhibited similar selectivity for the removal of unsaturated aliphatic hydrocarbons as for the removal of diolefins, with greater removal at higher contact temperatures.

The acidic molecular sieve of Example 3 of the present invention exhibited similar selectivity for the removal of unsaturated aliphatic hydrocarbons as for the removal of diolefins, with greater removal at higher contact temperatures.

Claims (10)

1. method for the treatment of the hydrocarbon incoming flow, this hydrocarbon incoming flow comprises aromatic substance, nitrogen compound and unsaturated lipid compounds of group, this method comprises: make a kind of contact the in this hydrocarbon incoming flow and the sorbent material that comprises clay, acidic molecular sieve and the activated carbon under contact conditions, removing this unsaturated lipid compounds of group and to produce treated hydrocarbon flow, contact conditions comprises at least 25 ℃ temperature and exists with respect to this hydrocarbon incoming flow water of the amount of 50ppm at least by weight.

2. according to the process of claim 1 wherein that water exists with the amount that equals or exceeds the saturation point of this hydrocarbon incoming flow under contact conditions.

3. according to the process of claim 1 wherein that water exists with the amount of 250ppm at least by weight for this hydrocarbon incoming flow.

According to the process of claim 1 wherein the contact this hydrocarbon incoming flow comprise this hydrocarbon incoming flow is contacted with clay absorbent and this temperature in 50 ℃ to 300 ℃ scopes.

According to the process of claim 1 wherein the contact this hydrocarbon incoming flow comprise this hydrocarbon incoming flow is contacted with acidic molecular sieve and this temperature in 45 ℃ to 115 ℃ scopes.

According to the process of claim 1 wherein the contact this hydrocarbon incoming flow comprise this hydrocarbon incoming flow is contacted with activated carbon and this temperature in 100 ℃ to 300 ℃ scopes.

7. according to the process of claim 1 wherein that this hydrocarbon incoming flow has the nitrogen content in 1ppm-wt to 10ppm-wt scope.

8. according to the process of claim 1 wherein that this nitrogen compound is the organic nitrogen compound that is selected from by the following group who forms: alkaline organic nitrogen compound, nitrile and composition thereof.

9. according to the process of claim 1 wherein that this unsaturated lipid compounds of group is diolefin compound.

10. according to the method for claim 9, wherein this diolefin compound is selected from the group who is made up of following: divinyl, pentadiene, dimethyl butadiene, hexadiene, methylpentadiene, dimethylbutadiene, acetylene and composition thereof.