Improved reforming process

Abstract

To provide an improved reforming process for producing aromatic hydrocarbons.SOLUTION: The process comprises two reformers arranged in a parallel flow configuration, wherein a first reformer is a conventional reformer comprising a catalyst selective for reforming C8+ hydrocarbons into reformate, and a second reformer comprises a catalyst selective for reforming C7- hydrocarbons into reformate. In a certain embodiment, the first reformer catalyst comprises a conventional alumina catalyst, and the second reformer catalyst comprises a ZSM-5 catalyst.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of priority of U.S. Provisional Patent Application No. 62 / 836,717, filed on April 21, 2019, the disclosure of which is hereby incorporated by reference in its entirety.

[0002] Field of the Invention The present invention relates to a reforming process for producing aromatic hydrocarbons, comprising two reformers in a parallel flow configuration, each reformer utilizing a catalyst having a specific hydrocarbon selectivity.

Background Art

[0003] Catalytic reforming is a basic petroleum refining process for upgrading light hydrocarbon - based feedstocks, often referred to as naphtha feedstocks. Such feedstocks mainly contain C6 - C 10 hydrocarbons. Products of catalytic reforming can include high - octane gasoline useful as automotive fuel; aromatic compounds such as benzene, toluene, xylene, and ethylbenzene; and hydrogen. Reactions typically involved in catalytic reforming include dehydrogenation, dehydrogenation cyclization, and isomerization of naphtha - range hydrocarbons, and dehydrogenation and dehydrogenation cyclization of straight - chain and slightly branched alkanes, as well as dehydrogenation of cycloalkanes, which result in the formation of aromatic compounds. Dealkylation and hydrocracking are generally undesirable reactions in the reforming process because any resulting light hydrocarbons generally have low commercial value and hydrogen is consumed.

[0004] Petroleum refiners and aromatic compound manufacturers face many challenges in the quest to improve catalytic naphtha reforming, both in terms of increasing octane number and / or aromatic compound yield and as a source of hydrogen to meet the ever-increasing hydrogen demand. For example, in conventional reforming systems, when operating a reformer under conditions that generally require catalytic reforming to be carried out at high temperature, low pressure, and / or a low H2:hydrocarbon ratio, which are conditions for high octane number, high production of aromatic compounds, and high production of hydrogen, in fixed-bed semi-regenerative reforming using conventional amorphous alumina catalysts, the catalyst life and liquid yield decrease rapidly. Under such conditions, when the catalyst life is short and more frequent catalyst regeneration is required, the operating efficiency and H2 production are significantly reduced. Moreover, the low selectivity of conventional catalysts for producing aromatic compounds from C6 and C7 paraffins is generally not economical for aromatic compound manufacturers.

[0005] Industrial reforming processes often include catalysts based on Group VIIIB metals such as platinum or palladium, or catalysts of the Group VIIIB metal + a second catalytic metal system. Suitable metals include rhenium, tin, tungsten, germanium, cobalt, nickel, rhodium, ruthenium, iridium, or combinations thereof. The above catalytic metal(s) can be dispersed on a support such as alumina, silica, or silica-alumina. Usually, a halogen such as chlorine is also incorporated on the above support. In addition to Group VIIIB metals, other reforming catalysts include aluminosilicate zeolite catalysts. For example, various patents including U.S. Patent Nos. 3,761,389, 3,756,942, 3,760,024, 4,927,525, 8,882,992, and 9,115,041 disclose the reforming and aromatization of hydrocarbon fractions using various catalysts. Other reforming catalysts including borosilicates and silicoaluminophosphates, layered crystalline clay-type phyllosilicates, and amorphous clays are also described in the literature.

[0006] To produce more valuable aromatics - modified oils, various processes for reforming naphtha feedstocks in one or more process steps are also described in patents and technical publications including, for example, U.S. Patent Nos. 3,415,737, 3,770,614, 3,950,241, 4,181,599, 4,190,519, 8,882,992, and 9,115,041. For example, many patents including U.S. Patent Nos. 4,627,909, 4,443,326, 4,764,267, 5,073,250, 5,169,813, 5,171,691, 5,182,012, 5,358,631, 5,376,259, 5,407,558, 8,882,992, and 9,115,041 also describe using different catalysts in different process steps during the reforming of naphtha feedstocks.

[0007] Advances in naphtha reforming catalysts and processes have benefited industrial reforming units, while there is a continuing need for the development of new and improved reforming processes and methods to increase the yield of aromatic compounds and process throughput, improve hydrogen production, and minimize the formation of low - value low - molecular - weight (C1 - C4) products. The present invention provides a solution to such industrial needs and the technical limitations of conventional reforming processes.

Summary of the Invention

[0008] The present invention is based on the discovery that by utilizing a plurality of reformers arranged in a parallel - flow configuration in which catalysts of different selectivities are used, an improvement in the overall aromatic compound yield and process throughput can be achieved in the reforming process. By splitting the entire naphtha reforming process feedstock mainly into a feed stream of C 7- and a feed stream of C 8+ and sending these intermediate streams to separate parallel reformers containing catalysts with appropriate selectivities, the present invention provides an advantageous yield and improved throughput compared to conventional reforming processes.

[0009] The reforming process of the present invention for producing aromatic hydrocarbons mainly separates a hydrocarbon-based feedstock containing a naphtha fraction into a first feed stream mainly containing C 8+ hydrocarbons and a second feed stream mainly containing C 7- hydrocarbons. Subsequently, the first feed stream or a fraction thereof is contacted with a first reforming catalyst in a first reformer equipped with the first reforming catalyst under first reforming conditions effective to form a first reformed oil. Similarly, the second feed stream or a fraction thereof is contacted with a second reforming catalyst in a parallel second reformer equipped with the second reforming catalyst under second reforming conditions effective to form a second reformed oil. The first catalyst is mainly selective for reforming C 8+ hydrocarbons into aromatic hydrocarbons, while the second catalyst is mainly selective for reforming C 7- hydrocarbons into aromatic hydrocarbons. The first and second reformers are arranged in a parallel flow configuration to reform the intermediate feed streams separately. The first and second aromatic reformed oils resulting from the parallel reformers, or fractions thereof, may be further combined into one to form a product and / or an intermediate stream for further processing.

[0010] The present invention also relates to a method for modifying an existing or conventional catalytic reforming process by integrating a second reformer with an existing or conventional reformer(s). The method generally includes adding a separation step to divide a hydrocarbon-based feedstock mainly containing a naphtha fraction into first and second intermediate feed streams mainly containing C 8+ and C 7- hydrocarbons, respectively. A second reformer in a parallel flow configuration with the existing or conventional reformer(s) is added to reform the C 7- hydrocarbon intermediate feed stream into aromatic reformed oil in the second reformer, and at the same time reform the C 8+ hydrocarbon intermediate feed stream into aromatic reformed oil in the existing or conventional reformer(s). The modified reformer process resulting from this method provides a hydrocarbon-based feedstock mainly containing a naphtha fraction, and separates the hydrocarbon-based feedstock into a first feed stream mainly containing C 8+ hydrocarbons and a second feed stream mainly containing C 7-separating into a second feed stream containing hydrocarbons, contacting the first feed stream or a fraction thereof with a first reforming catalyst in a first reformer comprising the first reforming catalyst under first reforming conditions effective to form a first aromatic reformate, wherein the first reforming catalyst is mainly C 8+ selective for reforming hydrocarbons to aromatic hydrocarbons, the contacting; contacting the second feed stream or a fraction thereof with a second reforming catalyst in a second reformer comprising the second reforming catalyst under second reforming conditions effective to form a second reformate, wherein the second reforming catalyst is mainly C 7- selective for reforming hydrocarbons to aromatic hydrocarbons, the contacting; optionally, combining the first reformate or a fraction thereof with the second reformate or a fraction thereof into one; comprising.

[0011] The drawings present representative views of a reformer process according to an embodiment of the present invention. It will be understood that the scope of the present invention is not limited to such representative views and is defined by the claims of this application.

Brief Description of the Drawings

[0012]

Figure 1

Embodiments for Carrying Out the Invention

[0013] In this specification, exemplary embodiments of one or more aspects are presented, but the disclosed system, process, and / or method can be implemented using any number of techniques. The present disclosure is not limited to the exemplary or specific embodiments, drawings, and techniques illustrated herein, including the exemplary designs and embodiments illustrated and described herein, but can be modified within the scope of the appended claims, together with all equivalents of their entire scope.

[0014] Unless otherwise indicated, the following words, terms, and definitions apply to this disclosure. If a term is used in this disclosure but not specifically defined herein, the definition from the IUPAC Compendium of Chemical Terminology, 2nd ed. (1997) may be applied, provided that the definition does not conflict with any other disclosure or definition applied herein, and provided that the definition does not render any claim to which the definition is applied unclear or inoperable. Any definition or usage presented by any document incorporated herein by reference shall be understood to be superseded by the definition or usage presented herein to the extent that the definition or usage presented herein conflicts therewith.

[0015] The boiling point temperatures disclosed herein are based on the ASTM D-2887 standard test method for the boiling range distribution of petroleum fractions by gas chromatography, unless otherwise indicated. The mid-boiling point is defined as the 50% (volume) distillation temperature based on the simulated distillation of ASTM D-2887.

[0016] The values of the number of carbon atoms of the hydrocarbons disclosed herein (i.e., C5, C6, C7, C8, C9, etc.) can be measured by standard gas chromatography methods.

[0017] Unless otherwise explicitly stated herein, in this specification, the feed rate to the catalytic reaction zone (e.g., reformer) is described as the volume of feed per unit volume of catalyst per unit time. The feed rates disclosed herein are also referred to as the liquid hourly space velocity, abbreviated as LHSV, and are described as the reciprocal of time (i.e., hr -1 )

[0018] In this specification, the C 4- stream contains a high proportion of hydrocarbons having 4 or fewer carbon atoms per molecule. Similarly, the C 5+ stream contains a high proportion of hydrocarbons having 5 or more carbon atoms per molecule. Similar interpretations apply to other carbon numbers and ranges. That is, the C 7-The stream contains a high proportion of hydrocarbons having 7 or fewer carbon atoms per molecule, while C 8+ The stream contains a high proportion of hydrocarbons having 8 or more carbon atoms per molecule. Those skilled in the art will recognize that hydrocarbon streams in petroleum refining processes are generally separated by boiling point range using a distillation process. Thus, C 7- The stream may even contain small amounts of C8 and C9 molecules. However, normal distillation will be designed and operated such that at least about 70 volume % of the C 7- stream contains molecules having 7 or fewer carbon atoms per molecule. Thus, at least about 70 volume %, or 80%, or 90% or more of the C 7- stream boils in the C 7- boiling point range. Similarly, at least about 70 volume %, or 80%, or 90% or more of the C 7- stream boils in the C 7- boiling point range.

[0019] The term "predominantly naphtha fraction" generally refers to a hydrocarbon composition consisting predominantly of the C6 - C 10 fraction, and more particularly (when specified), predominantly of the C6 - C9 fraction. The term "predominantly" is used in its ordinary sense, i.e., the largest (most abundant) fraction in the composition. Naphtha may also contain lower and higher carbon number molecules such as C5 and C 11 ~C 12 hydrocarbons.

[0020] The term "silica to alumina ratio" refers to the molar ratio of silicon dioxide (SiO2) to aluminum oxide (Al2O3).

[0021] The term "molecular sieve" refers to a crystalline material that includes pores, cavities, or interstitial spaces of uniform size, into which molecules small enough to pass through them are adsorbed while larger molecules are not adsorbed. Examples of molecular sieves include zeolites and non-zeolite molecular sieves such as, but not limited to, zeolite analogs including SAPO (silicoaluminophosphate), MeAPO (metalloaluminophosphate), AlPO4 (aluminophosphate), and ELAPO (non-metal substituted aluminophosphate family).

[0022] As used in this disclosure, unless otherwise expressly indicated, the Periodic Table of the Elements referred to is the CAS version in the Handbook of Chemistry and Physics, 72 nd edition (1991 - 1992), published by the Chemical Abstract Service.

[0023] The terms "a", "an", and "the" are intended to include a plurality of alternatives, e.g., at least one. For example, the disclosure of "Group VIIIB metal" or "alkali metal" is intended to include, unless otherwise expressly indicated, one or more of the Group VIIIB metals or alkali metals, or a mixture or combination of two or more thereof.

[0024] In this process, a hydrocarbon-based feedstock mainly containing a naphtha boiling range fraction is processed in a reforming process in which two or more reformers are operated in a parallel flow configuration. The hydrocarbon-based feedstock is separated into a first feed stream mainly containing C 8+ hydrocarbons and a second feed stream mainly containing C 7- hydrocarbons, and each feed stream is separately sent to its respective reformer. In a representative configuration, the first feed stream is mainly C 8+While being supplied to a first reformer equipped with a first reforming catalyst that is selective for reforming hydrocarbons into aromatic hydrocarbons, a second feed stream is mainly C under second reforming conditions effective to form a second reformed aromatic oil. 7- It is supplied to a parallel second reformer equipped with a second reforming catalyst that is selective for reforming hydrocarbons into aromatic hydrocarbons.

[0025] The present invention further relates to a method for modifying an existing reforming process including a conventional reforming system that utilizes a catalyst selective for reforming hydrocarbons into aromatic hydrocarbons. The method generally includes adding a feed separation step and a parallel second reformer to an existing reformer system. More specifically, the separation step involves separating the hydrocarbon-based (naphtha) feed to the first (conventional) reformer into a first feed stream mainly containing C 8+ hydrocarbons and a second feed stream mainly containing C 8+ hydrocarbons. The second reformer added to the existing reforming process is added in a parallel flow configuration with the first reformer, and the second reformer is equipped with a second reforming catalyst that is selective for reforming hydrocarbons into aromatic hydrocarbons. The modified catalytic reforming process includes 7- providing a hydrocarbon-based feed mainly containing a naphtha fraction, 7- separating the hydrocarbon-based feed into a first feed stream mainly containing C hydrocarbons and a second feed stream mainly containing C hydrocarbons, 8+ contacting the first feed stream or a fraction thereof with a first reforming catalyst in a first reformer equipped with the first reforming catalyst under first reforming conditions effective to form a first reformed aromatic oil, wherein the first reforming catalyst is mainly C 7- selective for reforming hydrocarbons into aromatic hydrocarbons, contacting the second feed stream or a fraction thereof with a second reforming catalyst in a second reformer equipped with the second reforming catalyst under second reforming conditions effective to form a second reformed aromatic oil, wherein the second reforming catalyst is mainly C 8+ selective for reforming hydrocarbons into aromatic hydrocarbons, contacting the second feed stream or a fraction thereof with a second reforming catalyst in a second reformer equipped with the second reforming catalyst under second reforming conditions effective to form a second reformed aromatic oil, wherein the second reforming catalyst is mainly C 7-selectively contacting the hydrocarbon with a reformate to a reformed hydrocarbon, optionally combining a first aromatic reformate or a fraction thereof with a second aromatic reformate or a fraction thereof into one, and optionally mixing a portion of the hydrocarbonaceous (naphtha) feedstock that has not been separated into two feed streams with the first and second feed streams, respectively, and then reforming in the first and second reformers, respectively.

[0026] The present invention is based in part on the discovery that the overall performance of the reforming process is improved by the selective reforming of hydrocarbons, which is particularly beneficial as a modification of existing reformer processes. Primarily C 7- Adding a second reformer using a reforming catalyst that is selective for hydrocarbons, and separating the entire naphtha feedstock into C 7- and C 7- and C 8+ reformer feeds allows each reformer to be operated under conditions more suitable for each feed and to produce the desired aromatic reformate product.

[0027] The reforming process is generally operated under conditions selected for and with catalysts selected for dehydrogenation, dehydrogenation cyclization, and isomerization reactions to convert low octane paraffins and cycloparaffins to high octane products. Products with improved yields of aromatic compounds and / or products containing a large amount of octane are produced. In some embodiments, the reforming process can be operated under conditions for and with one or more catalysts for producing an increased net positive amount of hydrogen.

[0028] The reforming process of the present invention involves passing a separated feed stream through at least two reformers operating in parallel. Generally, each reformer is characterized by one or more reforming reaction vessels, each equipped with a catalyst and operating under reforming reaction conditions. The aromatic reformed oil products from each reformer, or fractions thereof, may be combined to form a final or intermediate product. To meet specific requirements of the process, the temperature of the feed to each reformer or the product from each reformer may be increased or decreased. Similarly, the pressure of each reformer may be increased or decreased according to the catalyst and operating requirements. As described above, the two reformers each utilize a catalyst having selectivity that is mainly compatible with the feed to each reformer, and as a result, the catalysts used are not the same. The second reformer is typically operated at a lower pressure than the first reformer. By operating the second reformer at a lower pressure than the first reformer, improvements are made including an increase in aromatic compound yield, minimization of undesirable hydrocracking / dealkylation reactions, an increase in hydrogen production, and an increase in the overall reforming system throughput. Taking an assumed scenario based on the present invention where the initial rate of the naphtha feed stream to an existing reformer (which becomes the first reformer in the new parallel configuration) is 100,000 barrels per day. This naphtha feed stream is separated into a C 7- feed stream and a C 8+ feed stream at a volume ratio of 3:7, producing a C 7- feed stream of 30,000 barrels per day and a C 8+ feed stream of 70,000 barrels per day. Since the existing reformer (here, the first reformer in the new parallel configuration) has a processing capacity for 100,000 barrels per day of feed, an additional C 8+ feed stream of 30,000 barrels per day can be added to the processing in this reformer. To produce this additional C 8+ feed stream of 30,000 barrels per day, a naphtha feed stream of 42,857 barrels per day is separated into a C 7- feed stream and a C 8+ feed stream at a volume ratio of 3:7, also producing an additional C 7- feed stream of 12,857 barrels per day. In the new parallel configuration, now a C8+ The feed stream is reformed in a first (existing) reformer, with a daily volume of 42,857 barrels of C 7- The feed stream is reformed in a second (newly installed) reformer. As a result, the total processing capacity increases from 100,000 barrels per day to 142,857 barrels of naphtha feed stream, which is an increase of 42,857 barrels per day and corresponds to more than 42 volume percent.

[0029] The processes and methods of the present invention involve separating a hydrocarbon-based (naphtha) feedstock into a C 7- distillate stream and a C 8+ distillate stream, and each stream is supplied to the first and second reformers, respectively, either indirectly or directly, and / or partially or wholly. Each of the first and second feed streams is preferably supplied entirely and directly to the first and second reformers, respectively, although a portion of each feed stream may be diverted to other process operations, and it is contemplated that each of these feed streams may be subjected to intermediate processing and then supplied to the reformers described above. As described above, a portion of the hydrocarbon-based (naphtha) feedstock that is not separated into two feed streams may be mixed with the first and second feed streams, respectively, and then reformed in the first and second reformers.

[0030] An important aspect of the present invention is to recognize the advantages resulting from using a catalyst selective for the reforming of C 7- hydrocarbons in a parallel flow configuration with a conventional reforming process. In certain embodiments, such a catalyst may include a zeolite having a molar ratio of silica to alumina of at least 200, or at least 400, or at least 500, or at least 1000, or at least 1500, or at least 2000 and a crystallite size of less than 10 microns. C 7-Representative catalysts selective for hydrocarbon reforming include ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48, MCM-22, SSZ-20, SSZ-25, SSZ-26, SSZ-32, SSZ-33, SSZ-35, SSZ-37, SSZ-42, SSZ-43, SSZ-44, SSZ-45, SSZ-47, SSZ-58, SSZ-74, SUZ-4, EU-1, NU-85, NU-87, NU-88, IM-5, TNU-9, ESR-10, TNU-10, or combinations thereof. More detailed or preferred representative examples of such catalysts include ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48, or combinations thereof. C 7- Catalysts particularly useful or preferred for hydrocarbon reforming include ZSM-5, and more particularly, ZSM-5 having a molar ratio of silica to alumina of at least 200, or at least 400, or at least 500, or at least 1000, or at least 1500, or at least 2000.

[0031] The above C 7- The catalyst (second reformer catalyst) selective for hydrocarbon reforming typically contains a Group VIIIB metal in the range of 0.1 wt% to 5 wt%, or 0.1 wt% to 2 wt%, or 0.1 wt% to 1 wt%, or 0.2 wt% to 0.6 wt%, or a Group VIIIB metal selected from nickel, ruthenium, rhodium, palladium, iridium, platinum, or combinations thereof, or a Group VIIIB metal selected from iridium, palladium, platinum, or combinations thereof, or a Group VIIIB metal containing platinum. Typically, the second reformer catalyst contains platinum and, optionally, a Group VIIIB metal other than platinum in the range of 0.1 wt% to 5 wt%, or 0.1 wt% to 2 wt%, or 0.1 wt% to 1 wt%, or 0.2 wt% to 0.6 wt%, or a metal selected from rhenium, germanium, tin, lead, gallium, indium, or combinations thereof, or a metal containing rhenium.

[0032] The above C 7- Further details of catalysts suitable as catalysts selective for hydrocarbon reforming (second reformer catalysts) are available, for example, in U.S. Pat. Nos. 8,882,992 and 9,115,041, and other patents and publications.

[0033] The above C 8+ Catalysts selective for hydrocarbon reforming generally include non-zeolite naphtha reforming catalysts or alumina-supported non-zeolite catalysts containing Group VIIIB metals. Such catalysts are typically used as reforming catalysts in industrial processes, such as in the catalysts and processes of Platformers and Rheniformers.

[0034] An example of a Group VIIIB metal is platinum. The above catalysts may further contain promoters such as rhenium, tin, tungsten, germanium, cobalt, nickel, iridium, rhodium, ruthenium, or combinations thereof. In some such embodiments, the promoter metal is rhenium or tin.

[0035] When present, sufficient promoter metal is typically included to provide a promoter-to-platinum ratio of from 0.5:1 to 10:1, more preferably from 1:1 to 6:1, and most preferably from 2:1 to 5:1. Some examples of conventional catalysts are presented in U.S. Pat. Nos. 3,631,216, 3,415,737, and 4,511,746.

[0036] The above catalysts may be incorporated with a halogen source such as an alkali or alkaline earth chloride, fluoride, iodide, or bromide. Other halogen sources include hydrogen halides such as hydrogen chloride, and ammonium halides such as ammonium chloride. A preferred halogen source is a chlorine source. The amount of halogen source mixed with the above catalysts should be such that the catalyst contains from about 0.1 to 3 wt% halogen, more preferably from about 0.2 to about 1.5 wt% halogen, and most preferably 0.5 to 1.5 wt% halogen.

[0037] The above-mentioned metal may be disposed on a carrier such as refractory inorganic oxides such as alumina, silica, titania, magnesia, zirconia, chromia, thoria, boria, or mixtures thereof; synthetically prepared, naturally occurring, or optionally acid-treated clays or silicates; spinels such as MgAl2O4, FeAl2O4, ZnAl2O4, CaAl2O4; silicon aluminophosphates; and combinations of materials from one or more of these groups. The refractory carrier of the above-mentioned reforming catalyst preferably contains an inorganic oxide, more preferably alumina.

[0038] The reforming catalysts in the first and second reformers can be used in the form of pills, tablets, granules, fragments, or various special shapes, arranged as a fixed bed within the reaction zone, and the feedstock can pass through in a liquid phase, vapor phase, or mixed phase, either in an upward flow, downward flow, or radial flow. Alternatively, the above-mentioned reforming catalyst can be used in a moving bed or a fluidized solid process in which the feedstock passes upward through a turbulent bed of finely divided catalyst. Fixed bed systems or high-density phase moving bed systems can benefit from less catalyst attrition and other operating advantages. In a fixed bed system, the feedstock is preheated to the desired reaction temperature (by any optional and appropriate heating means) and then sent into the reaction zone equipped with the fixed bed catalyst. This reaction zone can be one or more separate reactors equipped with appropriate means for maintaining the desired temperature at the reactor inlet. Since the reforming process usually involves an endothermic reaction, it is necessary to maintain the temperature.

[0039] The above-mentioned mainly C 8+The reforming conditions in the first reformer equipped with a catalyst selective for hydrocarbon reforming depend at least in part on whether the feedstock used is highly aromatic, highly paraffinic, or highly naphthenic, and on the production of the desired aromatic reformed oil. The first reformer is generally operated under conditions that minimize the cracking of the feedstock stream being upgraded and extend the effective life of the reformer catalyst. The feedstock in the naphtha boiling range upgraded in the first reformer is at a temperature in the range of about 800°F to about 1100°F, preferably 850°F to 980°F; a pressure in the range of about 100 psig to about 500 psig, preferably 150 to 450 psi, more preferably 200 to 440 psi; 0.1 to about 3.0 hr -1 , preferably 0.5 to 2.5 hr -1 , more preferably 1.0 to 2.0 hr -1 of the feed rate LHSV; and is contacted with the first reformer catalyst under reaction conditions including an H2:HC (hydrogen to hydrocarbon) molar ratio in the range of 1:1 to 7:1, preferably 3:1 to 6:1. In some embodiments, the pressure in the first reformer is in the range of about 200 psig to about 400 psig.

[0040] The reaction conditions in the second reformer are specified to effectively utilize the performance advantages of the catalyst used at this stage. Generally, the second reformer is operated at a lower pressure and H2:HC (hydrogen to hydrocarbon) molar ratio than the first reformer. The above mainly C 7- The reforming conditions in the second reformer equipped with a catalyst selective for hydrocarbon reforming likewise depend at least in part on whether the feedstock used is highly aromatic, highly paraffinic, or highly naphthenic, and on the production of the desired aromatic reformed oil. The second reformer is generally operated under conditions that minimize the cracking of the feedstock stream being upgraded and extend the effective life of the reformer catalyst. The feedstock in the naphtha boiling range upgraded in the second reformer is at a temperature in the range of about 800°F to about 1100°F, preferably 850°F to 980°F; a pressure in the range of about 50 psig to about 300 psig, preferably 60 to 200 psi, more preferably 70 to 150 psi; about 0.1 to about 3.0 hr -1 , preferably 0.5 to 2.5 hr-1 and more preferably at 1.0 to 2.0 hours -1 contact with the second reformer catalyst under reaction conditions including a feed rate LHSV in the range of; a H2:HC (hydrogen to hydrocarbon) molar ratio in the range of 1:1 to 6:1, preferably 1.5:1 to 3:1. In some embodiments, the pressure in the second reformer is in the range of about 60 psig to about 100 psig.

[0041] Figure 1 shows an embodiment according to the present invention. A naphtha boiling range fraction 5 boiling within the range of 50°F to 550°F is fed to the separator 10 at a feed rate in the range of LHSV of about 0.5 hours -1 to about 6 hours -1 . The effluent 11 from the separator is fed to the first reformer 20 and is the first feed stream mainly of C 8+ . The effluent 12 from the separator is fed to the second reformer 30 and is the second feed stream mainly of C 7- . The first reformer 20 is equipped with a first catalyst selective for reforming mainly C 8+ hydrocarbons into aromatic hydrocarbons, and the second reformer 30 is equipped with a second reforming catalyst selective for reforming mainly C 7- hydrocarbons into aromatic hydrocarbons. The reformers 20 and 30 each produce reformed oils 21 and 31, respectively, which can be combined together to form a combined product reformed oil 25.

Examples

[0042] Example 1: The API gravity of the hydrorefined full boiling range naphtha feedstock was 59.9, and the simulated distillation of ASTM D-2887 was as shown in Table 1. The above feedstock contained 0.0 wt% benzene, 5.5 wt% toluene, and 4.2 wt% C8 aromatics as measured by GC analysis.

[0043] Example 2: The hydrorefined full boiling range naphtha feedstock of Example 1 was distilled into (A) a top cut and (B) a bottom cut.

[0044] (A) The API gravity of the top cut was 67.1 and the simulated distillation according to ASTM D-2887 was as shown in Table 1. The above top cut, as measured by GC analysis, contained 0.0 wt% benzene, 1.7 wt% toluene, and 0.0 wt% C8 aromatics. It was found that the above top cut corresponded to 30.7 wt% of the hydrotreated full boiling range naphtha feedstock of Example 1.

[0045] (B) The API gravity of the bottom cut was 56.9 and the simulated distillation according to ASTM D-2887 was as shown in Table 1. The above bottom cut, as measured by GC analysis, contained 0.0 wt% benzene, 7.2 wt% toluene, and 7.0 wt% C8 aromatics. It was found that the above bottom cut corresponded to 69.3 wt% of the hydrotreated full boiling range naphtha feedstock of Example 1.

Table 1

[0046] Example 3: Catalyst 1: The catalyst described in Example 2 of U.S. Patent No. 8,882,992. This catalyst was used in Example 5 to reform the hydrotreated full boiling range naphtha feedstock of Example 1 and in Example 7 to reform the bottom cut feedstock of Example 2B.

[0047] Example 4: Catalyst 2: The catalyst described in Example 3 of U.S. Patent No. 8,882,992. This catalyst was used in Example 6 to reform the top cut feedstock of Example 2B.

[0048] Example 5: The hydrotreated full boiling range naphtha feedstock of Example 1 was used as a feedstock for catalytic reforming using Catalyst 1 of Example 3. The reaction conditions included a temperature of 930°F, a pressure of 200 psig, a hydrogen to hydrocarbon molar ratio of 5:1, and a feed rate of 1.5 hr -1 of LHSV. C 5+The yield was 82.6 wt%. The effluent hydrocarbon stream, as measured by GC analysis, contained 4.5 wt% benzene, 19.6 wt% toluene, and 24.9 wt% C8 aromatics. The total C6 - C8 aromatics yield was 49.0 wt%.

[0049] Example 6: The top - cut feedstock of Example 2A was used as the feedstock for catalytic reforming using Catalyst 2 of Example 4. The reaction conditions included a temperature of 930°F, a pressure of 80 psig, a hydrogen - to - hydrocarbon molar ratio of 2:1, and a feed rate of 1.5 hr -1 LHSV. C 5+ The yield was 74.6 wt%. The effluent hydrocarbon stream, as measured by GC analysis, contained 14.4 wt% benzene, 32.5 wt% toluene, and 0.0 wt% C8 aromatics. The total C6 - C8 aromatics yield was 46.9 wt%.

[0050] Example 7: The bottom - cut feedstock of Example 2B was used as the feedstock for catalytic reforming using Catalyst 1 of Example 3. The reaction conditions included a temperature of 930°F, a pressure of 200 psig, a hydrogen - to - hydrocarbon molar ratio of 5:1, and a feed rate of 1.5 hr -1 LHSV. C 5+ The yield was 82.9 wt%. The effluent hydrocarbon stream, as measured by GC analysis, contained 0.8 wt% benzene, 16.6 wt% toluene, and 36.6 wt% C8 aromatics. The total C6 - C8 aromatics yield was 54.0 wt%.

[0051] Example 8: According to Example 2, the hydrotreated full - boiling - range naphtha feedstock of Example 1 was distilled into (A) a top - cut and (B) a bottom - cut. It was found that the top - cut corresponded to 30.7 wt% of the hydrotreated full - boiling - range naphtha feedstock of Example 1. It was found that the bottom - cut corresponded to 69.3 wt% of the hydrotreated full - boiling - range naphtha feedstock of Example 1.

[0052] These two cuts were each used as feedstocks for catalytic reforming in Examples 6 and 7. In this example, the products from these two cuts were mixed in a ratio corresponding to a feedstock mixture consisting of 30.7 wt% top cut feedstock (Example 2A) and 69.3 wt% bottom cut feedstock (Example 2B). It was revealed that this mixed product had 5.0 wt% benzene, 21.5 wt% toluene, and 51.8 wt% C8 aromatics. As a result, the total C6-C8 aromatics yield was 51.8 wt%. These yields were higher than those obtained in Example 5, where the entire hydrorefined full boiling range naphtha feedstock was reformed without pre-distillation into top and bottom cuts (Examples 2, 6, and 7), and the total C6-C8 aromatics yield was 49.0 wt%. This shows the advantage of combining Examples 6 and 7 over Example 5 in terms of the aromatic compound concentration in the total product stream.

[0053] Example 9: According to Example 2, the hydrorefined full boiling range naphtha feedstock of Example 1 was distilled into (A) a top cut and (B) a bottom cut. It was revealed that the top cut corresponded to 30.7 wt% of the hydrorefined full boiling range naphtha feedstock of Example 1. It was revealed that the bottom cut corresponded to 69.3 wt% of the hydrorefined full boiling range naphtha feedstock of Example 1.

[0054] These two cuts were each used as feedstocks for catalytic reforming in Examples 6 and 7. In this example, the products from these two cuts were mixed at a ratio corresponding to a feedstock mixture consisting of 30.7 wt% top cut feedstock (Example 2A) and 69.3 wt% bottom cut feedstock (Example 2B). It was found that this mixed product had 5.0 wt% benzene, 21.5 wt% toluene, and 51.8 wt% C8 aromatics. As a result, the total C6-C8 aromatics yield was 51.8 wt%. As shown in Example 8, these yields were higher than those obtained in Example 5, where the total boiling range naphtha feedstock that had been hydrorefined was reformed without pre-distilling it into top and bottom cuts (Examples 2, 6, and 7), and the total C6-C8 aromatics yield was 49.0 wt%.

[0055] Furthermore, the following assumptions were made to further compare the yields (barrels per day) of aromatic compounds in these examples according to the compositions of the products of Examples 5, 6, and 7.

[0056] (1) Case number 1: Assume that in Example 5 above, 100,000 barrels per day of hydrorefined total boiling range naphtha feedstock is reformed. In this case, an existing reformer equipped with the catalyst of Example 3 in a specified volume is used.

[0057] (2) If this hydrorefined total boiling range naphtha feedstock stream (100,000 barrels per day) is separated into a top cut (C 7- feedstock stream) and a bottom cut (C 8+ feedstock stream) at a volume ratio of approximately 3:7 (close to the 30.7:69.3 weight ratio of Example 2), there will be a C 7- feedstock stream of 30,000 barrels per day (Example 2A) and a C 8+ feedstock stream of 70,000 barrels per day (Example 2B).

[0058] (3) Since the existing reformer equipped with the same amount of the same catalyst (see Case number 1 above) has a processing capacity for 100,000 barrels per day of feedstock, the C8+ For the treatment of the feed stream, 30,000 barrels per day of C 8+ feed streams can be added.

[0059] (4) To produce this additional 30,000 barrels per day of C 8+ feed stream, 42,857 barrels per day of hydrotreated full boiling range naphtha is separated from C 7- feed stream and C 8+ feed stream at a volume ratio of 3:7, and further 12,857 barrels per day of C 7- feed stream is produced.

[0060] (5) Case number 2: In this case, as shown in Example 7, in an existing reformer, a total of 100,000 barrels per day of C 8+ feed stream is reformed (instead of the 70,000 barrels per day of C 8+ feed stream in Case number 1 above).

[0061] (6) Case number 3: In this case, a total of 42,857 barrels per day of C 7- feed stream is available. Based on the present invention, as shown in Example 6, a new reformer is added and this C 7- feed stream is reformed (instead of the 30,000 barrels per day of C 7- feed stream in Case number 1 above).

[0062] (7) Case Number 4: When combining Case Number 2 and Case Number 3 to form Case Number 4, the total processing capacity increases from 100,000 barrels per day (Case Number 1) to 142,857 barrels per day (Case Number 4) of hydrotreated full boiling range naphtha feedstock stream, resulting in an increase of 42,857 barrels per day, or 42.857 volume%. According to the product compositions of Examples 5, 6, and 7, the aromatic yield increases by approximately 1.8 times when changing from Case Number 1 to Case Number 4. This example (Example 9) shows that the combination of Example 6 and Example 7 is advantageous not only from the perspective of the aromatic concentration (weight% or volume%) in the total product stream (Example 8) but also from the perspective of the production rate of aromatic compounds (barrels per day) (this example) with respect to Example 5.

[0063] It will be recognized that the foregoing description of one or more embodiments of the invention is primarily for purposes of illustration, and that variations within the scope of the invention as set forth in the appended claims are possible.

[0064] All patents and publications cited in the foregoing description of the invention are hereby incorporated by reference into this specification.

Claims

1. Providing a hydrocarbonaceous feedstock comprising primarily a naphtha fraction; The hydrocarbon-based raw material is mainly ８＋ a first feed stream comprising a hydrocarbon; ７－ a second feed stream comprising hydrocarbons; and contacting the first feedstream, or a fraction thereof, with a first reforming catalyst in a first reformer comprising said first reforming catalyst under first reforming conditions effective to form a first reformate, said first reforming catalyst being composed primarily of C ８＋ said contacting being selective for the reforming of hydrocarbons to aromatic hydrocarbons; contacting the second feedstream, or a fraction thereof, with a second reforming catalyst in a second reformer comprising said second reforming catalyst under second reforming conditions effective to form a second reformate, said second reforming catalyst comprising primarily C ７－ said contacting a first reformer selective for the reforming of hydrocarbons to aromatic hydrocarbons and in a parallel flow configuration with said first reformer; Optionally, combining the first reformate or fraction thereof with a second reformate or fraction thereof; 2. A reforming process for producing aromatic hydrocarbons, comprising:

2. Mainly C ８＋ 1. A method for modifying a catalytic reforming process comprising: a first reformer comprising a first reforming catalyst selective for reforming hydrocarbons to aromatic hydrocarbons, the method comprising: The hydrocarbon feedstock to the first reformer, which mainly contains naphtha fraction, is mainly C ８＋ a first feed stream comprising a hydrocarbon; ７－ a second feed stream comprising hydrocarbons; and The catalytic reforming process mainly comprises C ７－ adding a second reformer in a parallel flow configuration with the first reformer, the second reformer comprising a second reforming catalyst selective for reforming hydrocarbons to aromatic hydrocarbons; Including, The modified catalytic reforming process comprises: Providing a hydrocarbonaceous feedstock comprising primarily a naphtha fraction; The hydrocarbon-based raw material is mainly ８＋ a first feed stream comprising a hydrocarbon; ７－ a second feed stream comprising hydrocarbons; and contacting the first feedstream, or a fraction thereof, with a first reforming catalyst in a first reformer comprising said first reforming catalyst under first reforming conditions effective to form a first reformate, said first reforming catalyst being composed primarily of C ８＋ said contacting being selective for the reforming of hydrocarbons to aromatic hydrocarbons; contacting the second feedstream, or a fraction thereof, with a second reforming catalyst in a second reformer comprising said second reforming catalyst under second reforming conditions effective to form a second reformate, said second reforming catalyst comprising a first reforming catalyst and a second reforming catalyst comprising a second reforming catalyst and a second reforming catalyst comprising a second reforming catalyst and a second reforming catalyst comprising a second reforming catalyst and a second reforming catalyst ７－ said contacting being selective for the reforming of hydrocarbons to aromatic hydrocarbons; Optionally, combining the first reformate or fraction thereof with a second reformate or fraction thereof; The method comprising:

3. 3. The process of claim 1 or the method of claim 2, wherein the first catalyst and the second catalyst are not the same.

4. Said C ７－ The hydrocarbon fraction is ７－ 3. The process of claim 1 or the method of claim 2, wherein the catalyst is selective for the reforming of hydrocarbons to aromatic hydrocarbons and is fed directly or indirectly to the catalyst.

5. Said C ８＋ The hydrocarbon fraction is ８＋ 3. The process of claim 1 or the method of claim 2, wherein the catalyst is selective for the reforming of hydrocarbons to aromatic hydrocarbons and is fed directly or indirectly to the catalyst.

6. C ７－ 3. The process of claim 1 or the method of claim 2, wherein the catalyst selective for hydrocarbon reforming comprises a zeolite having a silica to alumina molar ratio of at least 200, or at least 400, or at least 500, or at least 1000, or at least 1500, or at least 2000, and a crystallite size of less than 10 microns.

7. C ７－ 3. The process of claim 1 or the method of claim 2, wherein the catalyst selective for hydrocarbon reforming is selected from ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48, MCM-22, SSZ-20, SSZ-25, SSZ-26, SSZ-32, SSZ-33, SSZ-35, SSZ-37, SSZ-42, SSZ-43, SSZ-44, SSZ-45, SSZ-47, SSZ-58, SSZ-74, SUZ-4, EU-1, NU-85, NU-87, NU-88, IM-5, TNU-9, ESR-10, TNU-10, or combinations thereof.

8. C ７－ 3. The process of claim 1 or the method of claim 2, wherein the catalyst selective for hydrocarbon reforming is selected from ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48, or combinations thereof.

9. C ７－ 3. The process of claim 1 or the method of claim 2, wherein the catalyst selective for hydrocarbon reforming comprises ZSM-5.

10. 10. The process or method of claim 9, wherein the ZSM-5 has a silica to alumina molar ratio of at least 200, or at least 400, or at least 500, or at least 1000, or at least 1500, or at least 2000.

11. C ７－ 3. The process of claim 1 or the method of claim 2, wherein the catalyst selective for hydrocarbon reforming comprises in the range of 0.1 wt % to 5 wt %, or 0.1 wt % to 2 wt %, or 0.1 wt % to 1 wt %, or 0.2 wt % to 0.6 wt % of a Group VIIIB metal or a Group VIIIB metal selected from nickel, ruthenium, rhodium, palladium, iridium, platinum, or combinations thereof, or a Group VIIIB metal selected from iridium, palladium, platinum, or combinations thereof, or a Group VIIIB metal comprising platinum.

12. C ７－ 3. The process of claim 1 or the method of claim 2, wherein the catalyst selective for hydrocarbon reforming comprises in the range of 0.1 wt % to 5 wt %, or 0.1 wt % to 2 wt %, or 0.1 wt % to 1 wt %, or 0.2 wt % to 0.6 wt % of a Group VIIIB metal other than platinum, or a metal selected from rhenium, germanium, tin, lead, gallium, indium, or combinations thereof, or a metal comprising rhenium.

13. C ８＋ 3. The process of claim 1 or the method of claim 2, wherein the catalyst selective for reforming of hydrocarbons comprises a non-zeolitic naphtha reforming catalyst or an alumina supported non-zeolitic catalyst containing a Group VIIIB metal.

14. Said C ７－ The reforming of hydrocarbons to aromatic hydrocarbons comprises the steps of: a pressure in the range of 50 to 300 psi, preferably 60 to 200 psi, more preferably 70 to 150 psi; a temperature in the range of 800° F. to 1100° F., preferably 850° F. to 980° F.; and a time of 0.1 to 3.0 hr. －１ , preferably 0.5 to 2.5 hr －１ , more preferably 1.0 to 2.0 hr －１ and H in the range of 1:1 to 6:1, preferably 1.5:1 to 3:

1. ２ 3. The process of claim 1 or the method of claim 2, comprising the condition of a molar ratio of 0.1 to 0.5:

1.

15. Said C ８＋ The reforming of hydrocarbons to aromatic hydrocarbons comprises the steps of: a pressure in the range of 100 to 500 psi, preferably 150 to 450 psi, more preferably 200 to 440 psi; a temperature in the range of 800° F. to 1100° F., preferably 850° F. to 980° F.; and a time of 0.1 to 3.0 hr. －１ , preferably 0.5 to 2.5 hr －１ , more preferably 1.0 to 2.0 hr －１ LHSV in the range of 1:1 to 7:1, preferably 3:1 to 6:1 ２ 3. The process of claim 1 or the method of claim 2, comprising the condition of a molar ratio of 0.1 to 0.5:1.

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