MXPA01005456A - Isomerization of hydrocarbons - Google Patents

Abstract

An isomerization process for converting an isomerization feed stream containing alkanes having 4 carbon atoms to 10 carbon atoms per molecule and cycloalkanes having 5 carbon atoms to 10 carbon atoms per molecule to at least one product hydrocarbon isomer. The isomerization feed stream, which contains at least one feed hydrocarbon and hydrogen, is contacted in an isomerization zone at effective isomerization conditions with a catalyst where deactivation of such catalyst occurs in the isomerization zone. The isomerization process includes the presence of an additive in the isomerization feed stream. Theconcentration of the additive is sufficient to alleviate or diminish the deactivation of the catalyst and to maintain a substantially constant conversion of the at least one feed hydrocarbon to the at least one product hydrocarbon isomer at effective isomerization conditions.

Description

ISOMERIZATION OF HYDROCARBONS BACKGROUND OF THE INVENTION The present invention relates to an isomerization process and to the prevention of the deactivation of an isomerization catalyst used in such a process.

The isomerization of normal alkanes, i.e., normal paraffins, is widely used in refinery processes for the increase of hydrocarbons of lower value to higher value hydrocarbons. In recent years there has been an increased interest in the isomerization of normal alkanes, which have from about 4 carbon atoms to about 10 carbon atoms, to isoalkanes, particularly the isomerization of normal butane to isobutane, and also, from normal to 2 hexane. , 2-dimethylbutane. Due to recent federal mandates concerning gasoline vapor pressure, it is desirable that components high vapor pressure, such as normal butane and normal hexane, be removed from the gasoline tank. However, in the removal of such components high vapor pressure there must be some other use for such components. Thus, for example, isomerization of butane is beneficial because the isomerization of n-butane produces isobutane that can be used as a material Ref: 129850 for supplying other refinery processes, such as alkylation and etherification, that produce components for high octane gasoline. It is well known to use supported platinum catalysts (such as platinum in alumina) for the isomerization of hydrocarbons, in particular normal alkanes to isoalkanes (such as n-butane to isobutane). A problem encountered in hydrocarbon isomerization is the rapid deactivation of the isomerization catalyst. It is believed that there are a number of causes of deactivation of the catalyst. One cause of deactivation of the catalyst is the formation and accumulation of high molecular weight hydrocarbons, such as C5 to C8 hydrocarbons, carbon, and / or coke, in the pores of the isomerization catalyst, particularly at the reaction sites, also referred to as acid sites, in the isomerization catalyst as well as on the surface of the isomerization catalyst. The formation and accumulation of such high molecular weight hydrocarbons causes a high rate of deactivation of the catalyst, a short duty cycle life of the catalyst, and an unstable yield of the hydrocarbon products. In addition, the impurities present in the feed stream contribute to a rapid decrease in catalyst activity. Pre-treatment of the feed stream prior to isomerization to remove a larger portion of these impurities is an option to help mitigate catalyst deactivation, but this route is expensive because additional equipment and operating costs are required. In addition, the levels of these impurities in the feed stream could fluctuate, and pretreatment of the feed stream may not always be adequate. Another option to mitigate the deactivation of the isomerization catalyst by impurities is to operate the isomerization processes at relatively high hydrocarbon to hydrogen ratios and at relatively high temperatures. However this route is also expensive and generally produces less quantities of desirable isomer (s) product (s) and more quantities of undesirable byproducts, mainly light gases that are formed by catalytic hydro-pyrolysis of the fed hydrocarbons.

BRIEF DESCRIPTION OF THE INVENTION It is desirable to carry out the isomerization of an isomerization feed stream comprising an alkane (s) (ie, paraffins), and / or a cycloalkane (s) (ie, cycloparaffins), hydrogen, and also impurities in the presence of a catalyst, which contains platinum and a support material such as alumina, and also in the presence of an additive (s) of the isomerization feed stream to mitigate or decrease the deactivation of such a catalyst. Again it is desirable to provide a method by which the activity or life of the work cycle of an isomerization catalyst can be increased or extended essentially at a substantially constant conversion, i.e., isomerization, of hydrocarbons. Again it is desirable to provide a method by which the activity of an isomerization catalyst can be increased during the use of such a catalyst in the isomerization of hydrocarbons. Again, it is desirable to provide a method that allows economic isomerization of alkanes, such as normal paraffinic hydrocarbons, to isoalkanes, i.e. , isoparaffins, while achieving an exceptionally long operating life and useful for the associated isomerization catalyst. The present invention is directed to a more effective method for mitigating or reducing catalyst deactivation problems caused, for example, by the formation and accumulation of high molecular weight hydrocarbons within the pores of such a catalyst and the presence of impurities in the catalyst. the isomerization feed streams, comprises adding an additive to the isomerization feed stream to counteract such catalyst deactivation problems. The amount of additive used is important to mitigate or diminish the effects of deactivation of the catalyst, which helps to promote a substantially constant isomerization, i.e., conversion, of hydrocarbons. The present invention provides a process that allows only the isomerization of isomerizable hydrocarbons in an isomerization zone, while mitigating or decreasing catalyst deactivation problems using an additive in significantly lower concentrations than those indicated in the prior art that are acceptable or preferred. . What is particularly unusual about the current invention is the mitigation or reduction of catalyst deactivation problems by such not ordinarily low concentration of the additive. The inventive process includes converting at least one hydrocarbon feed selected from the group consisting of alkanes (preferably normal, linear alkanes) containing from about 4 carbon atoms to about 10 carbon atoms per molecule, and cycloalkanes containing from about 5 atoms carbon to about 10 carbon atoms per molecule, to at least one hydrocarbon isomer of the product, ie, a i isoalkane. The isomerization feed stream comprises at least one feed of hydrocarbon and hydrogen. The isomerization feed stream i is contacted in an area of * Isomerization, which can be defined by a reactor vessel, under effective isomerization conditions with f a catalyst, which preferably contains platinum and alumina, wherein the deactivation of such catalyst normally occurs in such an isomerization zone. The inventive process pdes by the presence of an additive, which contains at least one metal halide compound added, Preferably such a metal halide compound is a metal chloride compound (e.g., aluminum chloride), in such an isomerization feed stream in an amount sufficient to mitigate or decrease the deactivation of a catalyst.

Isomerization and to maintain a substantially constant conversion, i.e., isomerization, of at least one hydrocarbon feed to at least one hydrocarbon isomer of the product under effective broth conditions. Preferably, the hydrocarbon feed is a mixture of n-hexane and methylcyclopentane. The n-hexane is isomerized in the process of this invention to 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, and 2 r 3-dimethylbutane, with 2,2-dimethylbutane which is the preferred isomer, and the methylcyclopentane is isomerized to cyclohexane. Another preferred hydrocarbon feed is n-butane which is isomerized in the process of this invention to isobutane. An organic chloride compound such as tetrachlorethylene could also be presented in the isomerization feed stream of the inventive process. The inventive process offers several benefits such as: (1) the ability to operate the process at very low hydrogen to hydrocarbon molar ratios (eg, a hydrogen to hydrocarbon molar ratio of less than 0.5: 1), (2) a reduction substantial in the amount of hydrogen used when compared to isomerization processes that do not use the inventive process, (3) extending the life of the catalyst work cycle which results in longer work cycles between the catalyst regenerations, (4) the ability to operate the process at relatively low temperatures, and (5) fewer catalyst regeneration cycles which translates into safer operation, shorter downtime, and greater economic benefit. Other objects and advantages of the invention will be apparent from the detailed description of the invention and the appended claims.

DETAILED DESCRIPTION OF THE INVENTION Any linear or branched chain alkane containing in the range of about 4 carbon atoms to about 10 carbon atoms per molecule can be used as a hydrocarbon feed in the isomerization process of this invention. Non-limiting examples of suitable alkanes include, but are not limited to, n-butane (currently preferred), n-pentane, n-hexane (also currently preferred), 2-methylpentane, 3-methylpentane, n-heptane, 2-methylhexane , 3-methylhexane, octanes, nonanes, decanes, and the like and mixtures thereof. Any cycloalkane containing in the range of about 5 carbon atoms to about 10 carbon atoms per molecule can also be used as a hydrocarbon feed in the process of this invention. Non-limiting examples of suitable cycloalkanes include, but are not limited to, cyclopentane, cyclohexane, methylcyclopentane, cycloheptane, methylcyclohexane, cyclooctane, methylcyclooctane, and the like and mixtures thereof.

Mixtures of alkanes and cycloalkanes (such as a preferred hydrocarbon feed of a mixture of normal hexane and methylcyclopentane), in any proportion, such as a molar ratio of alkane (eg, normal hexane) to cycloalkane (eg, methylcyclopentane) of about 1 : 99 to approximately 99: 1, they can also be used as a hydrocarbon feed in the isomerization process of this invention. Another preferred hydrocarbon feed is a mixture of normal hexane, methylcyclopentane, and cyclohexane with a molar ratio of alkane (e.g., normal hexane) to cycloalkane (e.g., methylcyclopentane) from about 1:90 to about 90: 1. Any effective catalyst in hydrocarbon isomerization can be employed as the isomerization catalyst of this invention. Alkane isomerization catalysts that catalyze the conversion of C4 to C7 alkanes (preferably n-hexane, n-pentane, and n-butane) to isoalkanes are well known. Also commercially available are the preferred alkane isomerization catalysts, e.g., from UOP, Inc., Des Plaines, 111., and from the Catalyst and Chemicals Division of Engelhard Corporation, Ne ark, NJ. A catalyst suitable for use in the process of this invention contains platinum and a support material, preferably an inorganic support material. Examples of suitable support materials include, but are not limited to, alumina, chlorinated alumina, silica, titania, zirconia, aluminosilicates, zinc aluminate, zinc titanate, and mixtures thereof. A preferred catalyst contains platinum, alumina and also aluminum chloride. In general, the concentration of platinum in the catalyst is in the range of about 0.01 weight percent of the catalyst to about 10 weight percent of the catalyst. Preferably, the concentration of platinum in the catalyst is in the range of about 0.05 weight percent of the catalyst to about 1 weight percent of the catalyst, and, more preferably, the concentration of platinum in the catalyst is in the range of 0.1. percent by weight of the catalyst at 0.6 percent by weight of the catalyst. In general, the surface area of the catalyst is in the range of approximately 100m2 / g (measured by Brunauer, Emmet, Teller method, i.e., BET method) to approximately 800 m2 / g. The catalyst can be fresh (not used) or can be used and subsequently regenerated. Another catalyst for use in the process of this invention contains platinum and a zeolite. Examples of suitable zeolites include mordenite and also include, but are not limited to, those described in Kirk-Oth er Encyclopedia of Chemical Technology, third edition, volume 15, pages 638-669 (John Wiley & amp;; Sons, New York, 1981). Preferably, the zeolite has a restricted index (as defined in US Patent 4,097,367, which is incorporated herein by reference) in the range of about 0.4 to about 12, preferably in the range of about 2 to about 9. In general, the Molar ratio of Si02 to A1203 in the crystalline structure of the zeolite is at least about 5: 1 and can be in the range to infinity. Preferably the molar ratio of Si02 to Al203 in the zeolite structure is in the range of about 8: 1 to about 200: 1, more preferably in the range of about 12: 1 to about 100: 1. Preferred zeolites include ZSM-5, ZSM-8, ZSM-11, ZSM-12, ZSM-35, ZSM-38, and combinations thereof. Some of these zeolites are also known as "MFI" or "Pentasil" zeolites. In general, the content of platinum in the catalyst containing zeolite is the same as described above for the catalyst containing an inorganic support such as alumina. Any suitable isomerization condition (also referred to as hydroisomerization) can be employed in the process of this invention. In general, the feed of hydrocarbon (s) and hydrogen, preferably hydrogen gas, are premixed to provide an isomerization feed stream which is then charged to an isomerization zone, which can be defined by a reaction vessel, and is in contact with the catalyst contained therein at a reaction temperature, ie, isomerization, of at least about 27 ° C (about 80 ° F). Preferably the reaction temperature is in the range of about 38 ° C to about 315 ° C (about 100 ° F to about 600 ° F), more preferably the reaction temperature is in the range of about 49 ° C to about 310 °. C (about 120 ° F to about 575 ° F), and, more preferably, the reaction temperature is in the range of 60 ° C to 288 ° C (140 ° F to 550 ° F). In a preferred case of isomerization of n-hexane / methylcyclopentane in the presence of hydrogen (H2), the average reaction temperature in the catalyst bed is from about 60 ° C to about 177 ° C (about 140 ° F to about 350 ° C) F). In another preferred case of isomerization of n-butane in the presence of hydrogen (H 2), the average reaction temperature in the catalyst bed is from about 107 ° C to about 232 ° C (about 225 ° F to about 450 ° F) . The reaction pressure may be in the range below atmospheric pressure and amounts up to 4823 kPa (approximately 700 pounds per square inch absolute (psia), preferably, from about 101.3 kPa to about 4134 kPa (approximately atmospheric (ie, 14.7 psia ) at approximately 600 psia), and more preferably, from 103 kPa to 3789 kPa (15 psia to 550 psia) The hydrocarbon feed (s) can be contacted by any suitable means, method or manner with the catalyst contained within the isomerization zone The contacting step can be operated as a batch process step or, preferably, as a continuous process step.In the latter operation, a solid catalyst bed, or a moving catalyst bed, can be employed, or A bed of fluidized catalyst Any of these operational modes has advantages and disadvantages, and those skilled in the art can select the most suitable for a fluid and ca particular talizador. The flow velocity at which the hydrocarbon feed (s) (ie, the charge rate of a hydrocarbon feed) is charged to the isomerization zone is such that it provides a space velocity per hour of liquid volume ("LHSV"). ") in the range of exceeding 0 hour-1 and amounts to approximately 1000 hour-1. The term "space velocity per hour of liquid volume", as used herein, shall mean the numerical ratio of the rate at which at least one hydrocarbon feed is charged to the isomerization zone in liters per hour, divided by the liters of catalyst contained in the isomerization zone to which it is added. charges at least one hydrocarbon feed. The preferred LHSV of at least one hydrocarbon feed for the reaction zone may be in the range of about 0.25 hour "1 to about 250 hour" 1 and, more preferably, in the range 0.5 hour "to 100 hour". "1. In general, hydrogen is charged to the isomerization zone to thereby provide a molar ratio of hydrogen to hydrocarbon feed (s), ie, hydrogen to hydrocarbon molar ratio (H2: HC), used in the alkane isomerization process of This invention is generally in the range of about 0.01: 1 to about 20: 1, preferably in the range of about 0.02: 1 to about 5: 1, and more preferably, in the range of about 0.05: 1 to about 3: 1. . The product of isomerization, ie, the effluent leaving the isomerization zone, can be subjected to any suitable separation medium (eg, fractional distillation) to separate the desired hydrocarbon isomers from the products formed (eg, isobutane) from feeding of unconverted hydrocarbon (s) (eg, n-butane) and other hydrocarbons that may be present in the product. The hydrocarbon isomer of the product is thus recovered from the effluent. In the process of this invention, impurities can also occur in the isomerization feed stream. These impurities may include, but are not limited to, sulfur compounds, water, carbon dioxide, carbon monoxide, aromatic hydrocarbons containing in the range of about 6 carbon atoms to about 10 carbon atoms, such as, for example, , benzene, toluene, and xylene, olefin hydrocarbons containing in the range of about 2 carbon atoms to about 10 carbon atoms, and the like and combinations thereof. The amounts of these additional impurities should be small enough so that the impurities do not have detrimental effects in the process of this invention. In general, the total content of these impurities, if present, in the isomerization feed stream (in an elemental base, based on the weight of at least one hydrocarbon feed) is in the range of about 1 ppm of impurity to about 2000 ppm impurity (ie, from about 1 to about 2000 parts by weight of impurity per million parts by weight of at least one hydrocarbon feed). In most cases, the impurity content is in the range of about 10 ppm to about 200 ppm. The amount of water in the isomerization feed stream is either essentially zero or does not exceed about 1 ppm H20 (ie, about 1 part by weight H20 per million parts by weight of at least one hydrocarbon feed), and preferably should not exceed approximately 0.2 ppm H20. Thus, the hydrocarbon feed stream should be dry (using an effective desiccant, such as, but not limited to, silica gel, CaCl 2, alumina, molecular sieves and the like and mixtures thereof) to thereby reduce the water content of the hydrocarbon feed stream. the hydrocarbon feed stream to about 1 ppm H20 or less, preferably to about 0.2 ppm H20 or less and more preferably from about 0 ppm H20 to 0.1 ppm H20. It is also necessary to use enough dry hydrogen (which can be mixed with the hydrocarbon feed (s)) and, if necessary, use a desiccant (as described above) to dry the hydrogen, to ensure that the feed stream is isomerization of the hydrocarbon (s) and hydrogen feed do not contain more than about 0.2 ppm H20 (based on the weight of the hydrocarbon feed portion of the isomerization feed stream).

The deactivation effect of the catalyst is counteracted in the process of this invention by the presence, in the feed of isomerization, of an additive containing a metal halide compound, preferably such a metal halide compound is a chloride compound of metal. The presence of the additive in the isomerization feed stream can be achieved by adding the additive to the isomerization feed stream, which contains at least one hydrocarbon and hydrogen feed in an effective amount to counteract the deactivation of the isomerization catalyst used in such a process . It is also feasible to inject the additive into the hydrocarbon feed stream or into the hydrogen stream. Since both the hydrocarbon feed stream and the hydrogen stream are preferably mixed, to form the isomerization feed stream, before its contact with the catalyst, the final result will be essentially the same as injecting the additive into the feed stream. isomerization feed (containing at least one hydrocarbon and hydrogen feed). Examples of suitable metal chloride compounds include those typically found in Friedel-Crafts catalysts, and include, but are not limited to, aluminum chloride, antimony trichloride, antimony pentachloride, tin (II) chloride, tin chloride (IV), titanium (III) chloride, titanium (IV) chloride, zinc chloride, and the like and mixtures thereof. The preferred metal chloride compound at this time is aluminum chloride. Another suitable metal compound is boron trifluoride (BF3). In general, the effective amount of additive, preferably containing a metal chloride compound such as aluminum chloride (AlCl 3), in the isomerization feed stream, ie, the concentration of additive, preferably a metal chloride compound, in the isomerization feed stream, it is in the range of about 0.01 ppb of additive (preferably a metal chloride compound, more preferably A1C13) to about 300 ppb of additive (ie, about 0.01 part by weight additive per billion). parts by weight of at least one hydrocarbon feed to about 300 parts by weight of additive per billion parts by weight of at least one hydrocarbon feed). Preferably, the concentration of additive in the isomerization feed stream is in the range of about 0.05 ppb of additive to about 200 ppb of additive, more preferably, the additive concentration in the isomerization feed stream is in the range of 0.1. ppb of additive at 100 ppb of additive, and more preferably, the additive concentration in the isomerization feed stream is in the range of 0.1 ppb of additive to 60 ppb of additive. A compound of organic chloride and / or hydrogen chloride (such hydrogen chloride usually present as a result of the reaction of an organic chloride compound and hydrogen) could also be present in the isomerization feed stream of the inventive process. Examples of organic chloride compounds include, but are not limited to, carbon tetrachloride, tetrachlorethylene, hexachloroethane, 1-chlorobutane, 2-chlorobutane, 1-chloro-2-methylpropane, 2-chloro-2-methylpropane, and the like and mixtures thereof. The preferred organic chloride compound at this time is tetrachlorethylene (also called perchlorethylene or PCE). The additive, which preferably contains a metal chloride compound such as aluminum chloride (A1C13), could be mixed with the organic chloride compound such as PCE to form a mixture that can be injected into the hydrocarbon feed stream, the hydrogen feed, or preferably, into the isomerization feed stream of the hydrocarbon and hydrogen feed. The effective amount of such organic chloride compound, preferably perchlorethylene (PCE), in the isomerization feed stream, ie, the concentration of the organic chloride compound in the isomerization feed stream, is in the range of about 0.01 ppm of organic chloride compound to about 700 ppm of organic chloride compound (ie, from about 0.01 part by weight organic chloride compound per million parts by weight of at least one hydrocarbon feed to about 700 parts by weight organic chloride compound per million parts by weight of at least one hydrocarbon feed). Preferably, the concentration of organic chloride compound, preferably PCE, in the isomerization feed stream is in the range of about 0.05 ppm of organic chloride compound to about 600 ppm of organic chloride compound, more preferably, the concentration is in the range of about 0.1 ppm of organic chloride compound to about 500 ppm of organic chloride compound, and more preferably, the concentration of organic chloride compound is in the range of 0.5 ppm of organic chloride compound to 400 ppm of compound of organic chloride The amounts of the additive, preferably containing a metal chloride compound, and organic chloride compound, is injected into the hydrocarbon feed stream, the hydrogen feed stream, or, preferably, into the isomerization feed stream. of the hydrocarbon and hydrogen feed, should be such that the concentrations of the additive and the organic chloride compound recited above can be maintained. The injection of the additive and the organic chloride compound can be conducted continuously or intermittently, i.e., pulsed. The additive, which preferably contains a metal chloride compound such as aluminum chloride (AlCl 3), and the organic chloride compound are generally injected into the hydrocarbon feed stream, or into the hydrogen stream, or preferably, into the isomerization feed stream of at least one hydrocarbon and hydrogen feed, which is passed to the resulting isomerization zone in the presence of additive and organic chloride compound in the isomerization zone. While it is not desired to relate to any particular theory, a reaction mechanism that is believed to be occurring in the inventive process which helps prevent deactivation of the catalyst is that hydrocarbons with high molecular weight, such as C5 hydrocarbons. C8, carbon, and / or coke, react with the free metal chloride, such as free aluminum chloride, present in the additive instead of forming and accumulating within the pores of the catalyst, particularly at the reaction sites within the catalyst . Another possible reaction mechanism is that the additive helps prevent hydrocarbons with high molecular weight and impurities (such as sulfur compounds, olefins, and aromatics) that are absorbed onto the surface of the catalyst under the reaction conditions of the isomerization process. One or more of these reaction mechanisms could occur and could still occur simultaneously. The following examples are presented to further illustrate the invention and not to be construed as unduly limiting the scope of the invention. The following examples illustrate the unexpected operation of the inventive process that mitigates or decreases the deactivation of a catalyst, while simultaneously using such a catalyst in the isomerization of hydrocarbons. The data presented demonstrates that deactivation problems normally encountered by an isomerization catalyst when contacted with hydrocarbons that can form isomers, under isomerization conditions can be mitigated or decreased by the new process that helps to promote a substantially constant isomerization of hydrocarbons. . This new process has the benefit of extending the useful life of the isomerization catalyst over the life of such a catalyst, decreasing the steps of cyclic activation and reactivation of such a catalyst that normally occur when the inventive process is not used.

EXAMPLE 1 CORRIDA I (CONTROL) In this example, laboratory scale tests are described to illustrate the process of this invention. A stainless steel reactor (having an internal diameter of approximately 1.9 cm (approximately 0.75 inches) and a height of approximately 71 cm (approximately 28 inches)) was filled with a layer (approximately 34.3 cm (approximately 13.5 inches) in height) of Alundum® (inert alumina particles having a surface area of 1 m2 / g or less), a layer (approximately 15 cm (approximately 6 inches) in height) of isomerization catalyst 1-8 Pt / alumina (sold by UOP, Des Plaines, IL, which contains about 0.2% by weight of Pt, about 45% by weight of Al, about 2.9% by weight of Cl, about 0.07% by weight of Mg, about 0.07% by weight of Ti, and the rest it is essentially chemically bonded oxygen and hydrogen, surface area: 195 m2 / g) and an upper layer (approximately 20 cm (approximately 8 inches) in height) of Alundum®. The contents of the reactor were heated to approximately 138 ° C (approximately 280 ° F) in the presence of hydrogen, and a feed containing liquid alkane (containing 98.1 volume percent normal butane liquid), which had a vapor pressure Reid of 255.6 kPa (37.1 pounds per square inch gauge (psig)), which had a density of approximately 4.87 pounds per gallon (ie, approximately 0.58 grams per cubic centimeter (g / cc)), and a molecular weight of approximately 58.2, of a Phillips Petroleum Company commercial refinery was introduced into the reactor at a space velocity per hour of liquid volume of approximately 4 hours "1. The feed containing alkane also contained approximately 1.3 volume percent isobutane liquid, approximately 0.6. percent by volume of neopentane liquid, approximately 0.2 volume percent of isopentane liquid, approximately 0.6 percent by volume of C5 + alkane liquid, various sulfur impurities (mainly methyl ethyl sulfide and carbon disulfide) equivalent to a total sulfur content of less than about 0.4 ppm S (in an elemental base), and less than about 1 ppm fluoride organic. The reaction pressure was about 3100 kPa (450 pounds per square inch gauge (psig)). To condition the catalyst, perchlorethylene (PCE), having a density of about 1625 g / cc, was added to the feed containing liquid alkane in an amount to thereby maintain a concentration of about 83 ppm of perchloro-ethylene (PCE) in the feed containing liquid alkane (ie, about 83 parts by weight of PCE per million parts by weight of at least one hydrocarbon feed) together with the hydrogen added. The hydrogen was introduced in an amount to thereby provide a hydrogen to hydrocarbon (H2: HC) molar ratio in the range of about 0.3: 1 to about 2.3: 1 for 28 hours. After this initial conditioning of the catalyst for 28 hours, and with the exception of the periodic hydrogen scavenging of the catalyst in the inrush current time periods of 43 hours, 70 hours, 126 hours and 162 hours, the activity and deactivation of the catalyst were evaluated over a period of time of about 243 hours at molar H2: HC ratios in the range of about 0.1: 1 to about 0.3: 1 with the concentration of PCE in the feed containing liquid alkane maintained at about 166 ppm PCE (ie, 166 parts by weight of PCE per million parts by weight of at least one hydrocarbon feed). The obtained isomerization product (containing isobutanes and unconverted normal butane) was analyzed by means of a gas chromatograph. The conversion, i.e., isomerization, was defined as the molar ratio of isobutanes formed in the product to all butanes (such as n-butane and isobutanes) in the product multiplied by 100 (also referred to as an isobutane product ratio)., in% or PR of i-C4, in%). Since the reactor temperature was maintained at approximately 138 ° C (approximately 280 ° F) throughout Run 1, the PR of i-C4, in% provided the deactivation measurement of the catalyst with some decrease in PR of i-C4 , in% which is an indicator of catalyst deactivation. No metal chloride additive was used in Run I. The results of Run 1 are summarized in the following Table I.

TABLE I As the data from Corrida I clearly show, butane isomerization decreased continuously in several H2: HC molar ratios throughout the run. At an H2: HC molar ratio in the range of about 0.20: 1 to about 0.23: 1, the isobutane product ratio, in% (PR of i-C4, in%) decreased 4.5 percent from 59.4 to 54.9 during a time period of the input current of approximately 42.5 hours. At an H2: HC molar ratio in the range of about 0.17: 1, the isobutane product ratio, in% (PR of i-C4, in%) decreased 5 percent from 56.0 to 50.6 over a period of time of the input current of approximately 31 hours. At an H2: HC molar ratio of approximately 0.12: 1, the isobutane product ratio, in% (PR of i-C4, in%) decreased approximately 6 percent from 51.1 to 44.9 during a time period of the current of entry for approximately 48 hours. The PR of i-C4, in%, decreased consistently and stably for a time at several H2: HC molar ratios, indicating a consistent and stable decrease in isomerization catalyst activity.

CORRIDA II t INVENTION) In order to prove the inventive process, Corrida II was conducted in the same way as the Corrida I control described above with the following exceptions. A mixture containing perchlorethylene (PCE) and an additive containing aluminum chloride (A1C13) was added to the feed containing liquid alkane (the composition of the feed was the same as that described above in Run I, Control) in a amount to maintain a concentration of approximately 1.8 ppb AlCl3 in the feed containing liquid alkane (ie, approximately 1.8 parts by weight of A1C13 per billion parts by weight of at least one hydrocarbon feed) and approximately 83 ppm PCE in the feed containing liquid alkane (ie, about 83 parts by weight of PCE per million parts by weight of at least one hydrocarbon feed). Similar to Run I (Control), the catalyst was conditioned with a hydrogen to hydrocarbon molar ratio (H2: HC) of about 2.7: 1 for 24 hours using the mixture of AlCl3 and PCE. The results of Corrida II are summarized below in Table II.

TABLE II * PR of i- • C4, in% is also referred to as the isobutane product ratio, in% which is defined as the molar ratio of isobutanes formed in the product to all butanes (such as n-butane and isobutanes) ) in the product multiplied by 100.

As the data from Corrida II clearly demonstrate, the isomerization of butane did not decrease, but remained stable at several H2: HC molar ratios throughout the run. At an H2: HC molar ratio of about 0.20: 1, the isobutane product ratio, in% (PR of i-C4, in%) remained stable at an average of about 48 over a period of time of the input stream of approximately 143 hours. At an H2: HC molar ratio in the range of about 0.13: 1 to about 0.14: 1, the isobutane product ratio, in% (PR of i-C4, in%) remained stable at an average of about 48 during a Time period of the input current of approximately 79.5 hours. The PR of i-C4, in% was consistent and stable at various molar ratios H2: HC, indicating that the isomerization catalyst activity was maintained by the inventive process.

The comparison of the data between Run I and Run II shows that the life of the isomerization catalyst work cycle can be extended by the new process and that the deactivation problems of the catalyst can be mitigated or diminished by the new process. The difference in the operation between the control run and the inventive run is certainly unexpected. It would not be expected that the use of an A1C13 additive in such low concentrations in the inventive process would increase the functioning of the isomerization catalyst.

EXAMPLE II CORRIDA III (CONTROL) Corrida III was conducted in the same manner as that described above for Corrida I with the following exceptions. A feed containing liquid alkane, which contained a mixture of normal hexane and methylcyclopentane in a 1.2: 1 weight ratio and had a density of 0.8 grams per cubic centimeter (g / cc) of a commercial Phillips Petroleum Company refinery was used. instead of the normal butane feed used in Run I, and introduced into the reactor at a rate per hour of liquid volume of approximately 2 hours "1 instead of 4 hours" 1 used in Run 1. A reactor temperature of 127 ° C (260 ° F) was used instead of 138 ° C (280 ° F) used in Run I. Feed containing liquid alkane, ie, normal hexane / methylcyclopentane feed, contained approximately 40.7% by weight of normal hexane, approximately 33.8% by weight of methylcyclopentane, approximately 19.1% by weight of cyclohexane, approximately 0.011% by weight of benzene, approximately 1.1% by weight of 2-methylpentane, approximately 4.3% by weight of 3- methylpentane, about 0.9% by weight of cyclopentane, about 0.2% by weight of normal pentane, about 0.2% by weight of 2,4-dimethylpentane, small amounts of C7 and C8 alkanes, and various sulfur impurities (mainly methyl ethyl sulfide) and carbon disulfide) equivalent to a total sulfur content of approximately 0.5 ppm S (in an elemental base). Activity and deactivation of the catalyst was evaluated over a period of time of approximately 478 hours at a molar ratio of hydrogen to hydrocarbon (H2: HC) of approximately 0.16: 1, with the concentration of PCE in the feed containing liquid alkane maintained at about 368 ppm PCE (ie, about 368 parts by weight of PCE per million parts by weight of at least one hydrocarbon feed). The obtained isomerization product was analyzed by means of a gas chromatograph. In addition to the conversion of C6, ie, isomerization of C6, which is defined as one percent by weight of converted normal hexane (conversion of n-C6, in%), the conversion of C6 was further defined as the molar ratio of 2. , 2-dimethylbutane formed (2,2-DMB) in the product to normal hexanes in the product multiplied by 100 (also referred to as the product ratio of 2,2-DMB to normal hexane, in% or PR of 2, 2 -DMB / n-C6, in%). Since the reactor temperature was maintained at approximately 126.2 ° C (260 ° F) throughout Run III, the conversion of n-C6, in% and the PR of 2, 2-DMB / n-C6, in% provided the measure of deactivation of the catalyst with any decrease in the conversion of n-C6, in% or the PR of 2, 2-DMB / n-C6, in% which is an indicator of the deactivation of the catalyst. The molar ratio of cyclohexane to methylcyclopentane was also recorded as an additional indicator of deactivation of the catalyst. No metal chloride additive was used in Run III. The results of Corrida III are summarized in the following Table III.

TABLE III1 As the data from Run II clearly demonstrate, isomerization of normal hexane / methylcyclopentane decreased throughout the run of 478 hours at an H2: HC molar ratio of approximately 0.16: 1. The conversion of n-C6, in%, decreased approximately 26 percent from 57.6 to 31.5. The PR of 2, 2-DMB / n-C6, in% decreased approximately 18 percent from 20.9 to 2.3. The molar ratio of cyclohexane to methylcyclopentane (CyC6 / MCP) decreased from 1.29 to 1.08. The conversion of n-C6, in%, PR of 2, 2-DMB / n-C6, in%, and CyC6 / MCP all decreased steadily and consistently over time at a molar ratio H2: HC of 0.16: 1, which indicates a consistent and stable decrease in the activity of the isomerization catalyst.

CORRIDA IV (INVENTION!) To test the inventive process, Run IV was conducted in the same way as Run III described above with the following exceptions: A feed containing liquid alkane, which contained a mixture of normal hexane and methylcyclopentane in a weight ratio of 1.8: 1 and had a density of 0.8 grams per cubic centimeter (g / cc) of a commercial refinery of Phillips Petroleum Company was used in place of the feed used in Corrida IV. The feed containing liquid alkane in Run IV contained about 51.5 wt% of normal hexane, about 28.3 wt% of methylcyclopentane, about 12.6 wt% of cyclohexane, about 0.014 wt% of benzene, about 2.0 wt% of 2-methylpentane, approximately 5.1% by weight of 3-methylpentane, approximately 0.01% by weight of cyclopentane, approximately 0.1% by weight of pentane, approximately 0.1% by weight of 2,4-dimethylpentane, small amounts of C7 and C8 alkanes, and various sulfur impurities (mainly methyl ethyl sulfide and carbon disulfide) equivalent to a total sulfur content of about 0.5 ppm S (in an elemental base). A mixture containing perchlorethylene (PCE) and an additive comprising aluminum chloride (AlCl 3) was added to the mixture containing liquid alkane, in an amount to thereby maintain a concentration of approximately 57 ppb of AlCl 3 in the feed containing liquid alkane (ie, about 57 parts by weight of AlCl 3 per billion parts by weight of at least one hydrocarbon feed) and about 368 ppm PCE in the feed containing liquid alkane (ie, about 368 parts by weight of PCE per million parts by weight of at least one hydrocarbon feed). The activity and deactivation of the catalyst was evaluated over a period of time of about 376 hours at a hydrogen to hydrocarbon molar ratio (H2: HC) of about 0.4: 1 at the concentration of A1C13, in the feed containing liquid alkane maintained at about 57 ppb of A1C13 and the concentration of PCE in the feed containing liquid alkane maintained at approximately 368 ppm PCE. The results of Corrida IV are summarized in the following Table IV.

TABLE IV1 1 All data obtained at a H2: HC molar ratio of approximately 0.4: 1. 2-PR of 2,2-DMB / n-C6, in% is also referred to as product ratio of 2,2-DMB to normal hexane, in% which is defined as the molar ratio of 2,2-dimethylbutane formed (2). , 2-DMB) in the product to normal hexanes in the product multiplied by 100. 3 Molar ratio of cyclohexane to methylcyclopentane.

As the data from Run IV clearly demonstrate, the isomerization of normal hexane / methylcyclopentane remained stable throughout the run of 376 hours at an H2: HC molar ratio of approximately 0.4: 1. The conversion of n-C6, in%, remained stable at an average of approximately 51.6. The PR of 2,2-DMB / n-C6, in% remained stable at an average of approximately 12. The molar ratio of cyclohexane to methylcyclopentane (CyC6 / MCP) remained stable at an average of approximately 1.12. The conversion of n-C6, in%, PR of 2, 2-DMB / n-C6, in%, and CyC6 / MCP remained all consistent and stable over time at an H2: HC molar ratio of 0.4: 1, which indicates that the activity of the isomerization catalyst was maintained by the inventive process.

The comparison of the data between Run III and Run IV shows that the life of the isomerization catalyst work cycle can be extended by the new process and that the deactivation problems of the catalyst can be mitigated or diminished by the new process. The drastically improved performance of the inventive run on the control run is certainly unexpected. The use of an A1C13 additive in such low concentrations in the inventive process would not be expected to improve the performance of the isomerization catalyst.

EXAMPLE III The following example demonstrates that the inventive process can be used to provide a substantial increase in the conversion of C6, ie, isomerization of C6, defined as the molar ratio of 2,2-dimethylbutane (2,2-DMB) formed in the product to normal hexanes in the product multiplied by 100 (also referred to as product ratio of 2,2-DMB to normal hexane, in% or PR of 2, 2-DMB / n-C6, in%), at a molar ratio hydrogen to substantially decreased hydrocarbon, and to a substantially decreased aluminum chloride concentration. Thus, the example demonstrates that catalyst deactivation problems can be mitigated or decreased even when the inventive process utilizes molar ratios of hydrogen to hydrocarbon and substantially decreased aluminum chloride concentrations. The example also demonstrates the effectiveness of the inventive process in the high severity of a hydrogen to low hydrocarbon molar ratio.

CORRIDA V (INVENTION) Run V was conducted in the same way as Run IV, described above in Example II, except that the hydrogen to hydrocarbon molar ratio is f reduced from about 0.4: 1 to about 0.1: 1, and the mixture containing perchlorethylene (PCE) and an additive comprising aluminum chloride (A1C13) added to the feed containing liquid alkane, was reduced in amount to maintain a concentration of approximately 27 ppb AlCl3, in the feed containing liquid alkane (i.e., approximately 27 parts by weight of A1C13 per billion parts by weight of at least one hydrocarbon feed), instead of about 57 ppb of A1C13, in the feed containing liquid alkane used in Run IV (ie, about 57 parts by weight of AlCl3 per billion parts in weight of at least one hydrocarbon feed), while the PCE concentration remained the same as Run IV at about 368 ppm PCE in the feed containing liquid alkane (ie, about 368 parts by weight of PCE per million parts by weight). weight of at least one hydrocarbon feed). The composition of the feed containing liquid alkane was the same as that described above for Run IV and was introduced in the rector to a space velocity per hour of the liquid volume of approximately 2 hours "1 which was the same as Run IV. The activity and deactivation of the catalyst were evaluated over a period of time of about 197 hours at a hydrogen to hydrocarbon molar ratio (H2: HC) of about 0.1: 1., with the concentration of AlCl3 in the feed containing liquid alkane maintained at approximately 27 ppb of A1C13 and the concentration of PCE in the feed containing liquid alkane maintained at approximately 368 ppm PCE. The results of Run V are summarized in the following Table V.

TABLE VJ As the data from Run V clearly demonstrate, the isomerization of normal hexane / methylcyclopentane remained stable throughout the run of 197 hours at an H2: HC molar ratio of approximately 0.1: 1. The conversion of n-C6, in%, remained stable at an average of approximately 64.2. The PR of 2,2-DMB / n-C6, in% remained stable at an average of approximately 33. The molar ratio of cyclohexane to methylcyclopentane (CyC6 / MCP) remained stable at an average of approximately 1.31. The conversion of n-C6, in%, PR of 2, 2-DMB / n-C6, in%, and CyC6: MCP remained all consistent and stable with time at an H2: HC molar ratio of approximately 0.1: 1 , which indicates that the activity of the isomerization catalyst was maintained by the inventive process. The comparison of the data between Run III and run V shows that the life of the isomerization catalyst work cycle can be extended by the new process and that the deactivation problems of the catalyst can be mitigated or diminished by the new process. In addition, the results demonstrate the effectiveness of the inventive process at the high severity of a H2: HC molar ratio of 0.1: 1. Even at a substantially reduced hydrocarbon to hydrocarbon molar ratio (the molar ratio of hydrogen to hydrocarbon was reduced from about 0.4: 1 (Run IV) to about 0.1: 1) and to a substantially decreased concentration of aluminum chloride in the feed containing alkane liquid (the concentration of AlCl3 in the feed containing liquid alkane was reduced from about 57 ppb (Run IV) to about 29 ppb), the inventive process was still effective in resolving or decreasing catalyst deactivation problems. The difference in operation between the control run and the inventive run is certainly unexpected. The use of an AlCl3 additive in such low concentrations in the inventive process would not be expected to improve the performance of the isomerization catalyst. The results shown in the previous examples clearly demonstrate that the present invention is well adapted to carry out the objectives and achieve the ends and advantages mentioned, as well as those inherent therein. Variations, modifications and reasonable adaptations for various conditions and reagents may be made within the scope of the description and appended claims, without departing from the scope of this invention. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (27)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A process for converting at least one hydrocarbon feed selected from the group consisting of alkanes containing in the range of 4 carbon atoms to 10 carbon atoms. of carbon per molecule, and cycloalkanes containing in the range of 5 carbon atoms to 10 carbon atoms per molecule to at least one product of hydrocarbon isomer, characterized in that an isomerization feed stream, comprising at least one hydrocarbon and Hydrogen feed is brought into contact in an isomerization zone at effective isomerization conditions with a catalyst, wherein the deactivation of the catalyst occurs in the isomerization zone, and further because the process comprises the presence of an additive in the stream of isomerization feed in a concentration in the range of 0.01 parts by weight of the additive per trillion parts by weight of at least one hydrocarbon feed (0.01 ppb of additive) to 300 parts by weight of the additive per trillion parts by weight of at least one hydrocarbon feed (300 ppb of additive) and in addition because the additive contains a metal chloride compound selected from the group consisting of aluminum chloride, antimony trichloride, antimony pentachloride, tin (II) chloride, tin (IV) chloride, titanium (III) chloride, titanium chloride (IV), zinc chloride, and mixtures thereof.
2. 2. A process according to claim 1, characterized in that the concentration of the additive in its isomerization feed stream is in the range of 0.05 parts by weight of the additive per billion parts by weight of at least one hydrocarbon feed (0.05). ppb of additive) to 200 parts by weight of the additive per trillion parts by weight of at least one hydrocarbon feed (200 ppb of additive).
3. 3. A process according to any preceding claim, characterized in that the metal chloride compound is aluminum chloride.
4. 4. A process according to any preceding claim, characterized in that an organic compound is present in the isomerization feed stream.
5. 5. A process according to claim 4, characterized in that the organic chloride compound is selected from the group consisting of carbon tetrachloride, tetrachlorethylene (also called perchlorethylene or PCE), hexachloroethane, 1-chlorobutane, 2-chlorobutane, l- chloro-2-methylpropane, 2-chloro-2-methylpropane, and mixtures thereof.
6. 6. A process in accordance with the claim 5, characterized in that the concentration of the organic chloride compound in the isomerization feed stream is in the range of 0.01 parts by weight of the organic chloride compound per million parts by weight of at least one hydrocarbon feed (0.01 ppm compound of organic chloride) to 700 parts by weight of the organic chloride compound per million parts by weight of at least one hydrocarbon feed (700 ppm organic chloride compound).
7. 7. A process in accordance with the claim 6, characterized in that the concentration of the organic chloride compound in the isomerization feed stream is in the range of 0.05 parts by weight of the organic chloride compound per million parts by weight of at least one hydrocarbon feed (0.05 ppm of compound of organic chloride) to 600 parts by weight of the organic chloride compound per million parts by weight of at least one hydrocarbon feed (600 ppm organic chloride compound).
8. 8. A process according to claim 7, characterized in that the organic chloride compound is tetrachlorethylene (also called perchlorethylene or PCE).
9. 9. A process according to any of the preceding claims, characterized in that the alkanes are selected from the group consisting of n-butane, n-pentane, n-hexane, 2-methylpentane, 3-methylpentane, n-heptane, 2-methylhexane, 3-methylhexane, octanes, nonanes, decanes and mixtures thereof.
10. 10. A process according to claim 9, characterized in that the alkanes are selected from the group consisting of n-butane and n-hexane.
11. 11. A process according to any of the preceding claims, characterized in that the cycloalkanes are selected from the group consisting of cyclopentane, cyclohexane, methylcyclopentane, cycloheptane, methylcic lohexane, cyclooctane, methylcyclooctane, and mixtures thereof.
12. 12. A process according to claim 11, characterized in that the cycloalkanes are selected from the group consisting of methylcyclopentane and cyclohexane.
13. 13. A process according to any of the preceding claims 1-8, characterized in that at least one hydrocarbon feed is n-butane.
14. 14. A process according to any of the preceding claims 1-8, characterized in that at least one hydrocarbon feed is a mixture of the alkanes and the cycloalkanes.
15. 15. A process according to any of the preceding claims 1-8, characterized in that at least one hydrocarbon feed is a mixture of normal hexane and methylcyclopentane.
16. 16. A process according to claim 16, characterized in that the molar ratio of normal hexane to methylcyclopentane in the mixture is in the range of 1:99 to 99: 1.
17. 17. A process according to any of the preceding claims 1-8, characterized in that at least one hydrocarbon feed is a mixture of normal hexane, methylcyclopentane and cyclohexane.
18. 18. A process according to claim 17, characterized in that the molar ratio of normal hexane to methylcyclopentane in the mixture is in the range of 1:90 to 90: 1.
19. 19. A process according to any of the preceding claims, characterized in that the feed stream comprises impurities selected from the group consisting of sulfur compounds, water, carbon dioxide, carbon monoxide, aromatic hydrocarbons containing in the range of 6. carbon atoms to 10 carbon atoms, olefin hydrocarbons containing in the range of 2 carbon atoms to 10 carbon atoms, and combinations thereof.
20. A process according to any of the preceding claims, characterized in that at least one hydrocarbon isomer of the product is recovered from the effluent leaving the isomerization zone.
21. 21. A process according to any of the preceding claims, characterized in that the effective isomerization conditions comprise: a reaction temperature in the range of 37.7 ° C to 316 ° C (100 ° F to 600 ° F), a pressure in the range of below atmospheric pressure that rises to 4823 kPa (700 pounds per square inch, absolute), a load rate of at least one hydrocarbon feed in the range of exceeding 0 hour-1 that rises to 1000 hour "1 and a molar ratio of hydrogen to hydrocarbon of at least one hydrocarbon feed in the range of 0.01: 1 to 20: 1
22. 22. A process according to any of the preceding claims, characterized in that the concentration of the additive in the stream isomerization feed is maintained by continuously injecting the additive into the isomerization feed stream
23. 23. A process according to any of the preceding claims 1-2 1, characterized in that the concentration of the additive in the isomerization feed stream is maintained by intermittently injecting the additive into the isomerization feed stream.
24. 24. A process according to any of the preceding claims, characterized in that the catalyst contains platinum and an organic support material.
25. 25. A process according to any of the preceding claims 1-23, characterized in that the catalyst contains platinum and a zeolite.
26. 26. A process according to claim 24, characterized in that the concentration of the platinum in the catalyst is in the range of 0.01 weight percent of the catalyst to 10 weight percent of the catalyst.
27. 27. A process according to claim 25, characterized in that the concentration of the platinum in the catalyst is in the range of 0.01 weight percent of the catalyst 10 percent by weight of the catalyst. F go