Systems and methods for maximizing aromatics and olefins production

Abstract

Methods and systems for forming olefins and aromatics from naphtha. The process comprises introducing a naphtha feed stream to an adsorption unit, the adsorption unit comprising an adsorbent. Normal paraffins are adsorbed from the naphtha feed stream to an adsorbent and an isoparaffin stream is removed from the adsorption unit. A desorbent stream is introduced into the adsorption unit, the desorbent stream comprising a desorbent, and the n-paraffins are removed from the adsorbent with the desorbent, thereby forming a desorbed bottom deposit. The n-paraffins are collected from the desorbed bottom deposits, thereby forming an n-paraffin stream. The n-paraffin stream is introduced into a steam cracking unit, and olefins and aromatics are formed from the n-paraffin stream in the steam cracking unit.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. application serial number 17 / 745,248, filed on May 16, 2022, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to systems and methods for processing petroleum-based materials, and more particularly to systems and methods for upgrading naphtha by steam cracking and converting it into petrochemical products such as aromatics and olefins. Background Art

[0004] Petrochemical feedstocks, such as naphtha, can be converted into chemical products and intermediates, such as olefins and aromatics, which are essential intermediates for much of the petrochemical industry. The increasing global demand for light olefins and aromatics remains a major challenge for many integrated refineries. In particular, the production of some valuable light olefins, such as ethylene, propylene, and butenes, has attracted increasing attention, as pure olefin streams are considered as building blocks for polymer synthesis. Additionally, aromatics, such as benzene, toluene, ethylbenzene, and xylenes, are valuable intermediates for the synthesis of polymers and other organic compounds, as well as for use in fuel additives.

[0005] Olefins and aromatics can be produced by steam cracking naphtha. In order to obtain higher olefin and aromatic yields, suitable feedstocks for the steam cracking process are generally rich in paraffinic hydrocarbons with lower concentrations of aromatic compounds, which can reduce the formation of unwanted by-products and coking during steam cracking. However, even paraffin-rich feed streams can lead to coking and unwanted by-products in steam cracking. Summary of the invention

[0006]

[0006] Therefore, there is a continuing need for systems and methods for increasing the yield of olefins and aromatics in a steam cracking process when naphtha is used as the feed stream to the cracking system.

[0007] Petroleum naphtha is a typical feed stream for steam cracking and reforming units. Petroleum naphtha generally includes both normal paraffins (n-paraffins) and isoparaffins. However, it is found that the efficiency of producing aromatics and olefins from petroleum naphtha by steam cracking does not reach the desired level. Therefore, it is found that in order to increase the product of aromatics and olefins in steam cracking, normal paraffins are more preferably the feed stream of steam cracker than isoparaffins, and isoparaffins are more preferably than naphthalene, and naphthalene is more preferably than aromatics. In contrast, reforming has an opposite preferred feed stream, wherein aromatics are more preferably the feed stream than naphthalene, and naphthalene is more preferably than isoparaffins, and isoparaffins are more preferably than normal paraffins.

[0008] Therefore, in order to increase the production of aromatics and olefins in steam cracking, the process disclosed and described herein separates the normal paraffins from the isoparaffins, naphthalenes and aromatics by one or more solid adsorption units before feeding the normal paraffins to the steam cracker and feeding the isoparaffins, naphthalenes and aromatics to various other reformers. By utilizing the process and system disclosed and described herein, the ethylene yield can be increased by more than 15 wt.%, the total olefin yield can be increased by 6 wt.%; the naphthalene and aromatics in the separated naphtha can be increased by 15 wt.%.

[0009] One aspect includes a method for forming olefins and aromatics from naphtha, comprising: introducing a naphtha feed stream into an adsorption unit, the adsorption unit comprising an adsorbent; adsorbing normal paraffins from the naphtha feed stream onto the adsorbent; removing an isoparaffin stream from the adsorption unit; introducing a desorbent stream into the adsorption unit, the desorbent stream comprising a desorbent; removing normal paraffins from the adsorbent with the desorbent, thereby forming desorbed bottoms; collecting normal paraffins from the desorbed bottoms, thereby forming a normal paraffin stream; introducing the normal paraffin stream into a steam cracking unit; and forming olefins and aromatics from the normal paraffin stream in the steam cracking unit.

[0010] Another aspect includes a system for forming olefins and aromatics from naphtha, the system comprising: an adsorption unit located upstream of and in fluid connection with a splitting unit and a steam cracking unit; the steam cracking unit located downstream of and in fluid connection with the adsorption unit, and the steam cracking unit located upstream of and in fluid connection with a separation unit; the splitting unit located downstream of and in fluid connection with the adsorption unit, and the splitting unit located upstream of and in fluid connection with an aromatization unit and a reforming unit; the aromatization unit located downstream of and in fluid connection with the splitting unit, and the aromatization unit located upstream of and in fluid connection with the separation unit; the reforming unit located downstream of and in fluid connection with the splitting unit, and the reforming unit located upstream of and in fluid connection with the separation unit; the separation unit located downstream of and in fluid connection with the aromatization unit and the reforming unit, and the separation unit located downstream of and in fluid connection with the steam cracking unit, wherein the adsorption unit comprises an adsorbent selected from the group consisting of zeolite 5A, zeolite T, chabazite, and erionite.

[0011] Additional features and advantages of the techniques described in the present disclosure will be set forth in the detailed description that follows, and will be readily apparent in part to those skilled in the art from that description or by practicing the techniques described in the present disclosure, including the detailed description that follows, the claims, and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The following detailed description of specific embodiments of the present disclosure may be best understood when read in conjunction with the following drawings, in which like structures are represented by like reference numerals and in which:

[0013] Figure 1 schematically depicts a generalized flow diagram of a system for forming olefins and aromatics from naphtha according to embodiments disclosed and described herein;

[0014] Figure 2 schematically depicts a generalized flow diagram of an adsorption unit according to embodiments disclosed and described herein; and

[0015] Figure 3 A generalized flow diagram of a steam cracking unit according to embodiments disclosed and described herein is schematically depicted.

[0016] To describe Figure 1-3 The simplified schematic diagram and description do not include many valves, temperature sensors, electronic controllers, etc. that can be used and known to ordinary technicians in certain chemical processing operations. In addition, accompanying components that are typically included in chemical processing operations, such as, for example, gas sources, heat exchangers, buffer tanks, or other related systems, are not depicted. It should be understood that these components are within the spirit and scope of the disclosed embodiments. However, operating components such as those described in the present disclosure can be added to the embodiments described in the present disclosure.

[0017] It should also be noted that the arrows in the accompanying drawings refer to process streams. However, arrows can equally refer to a delivery line that can be used to deliver a process stream between two or more system components. In addition, the arrows connected to the system components define the inlet or outlet in each given system component. The arrow direction generally corresponds to the main direction of movement of the material of the stream contained in the physical delivery line represented by the arrow. In addition, arrows that do not connect two or more system components represent the product stream of the system leaving the depicted system or the system inlet stream entering the depicted system. The product stream can be further processed in the accompanying chemical treatment system, or it can be commercialized as a final product. The system inlet stream can be a stream transferred from the accompanying chemical treatment system, or it can be an untreated raw material stream. Some arrows can represent a recycle stream, which is an outflow stream of the system components that are recycled back to the system. However, it should be understood that in some embodiments, any representative recycle stream can be replaced by the system inlet stream of the same material, and a part of the recycle stream can leave the system as a system product.

[0018] In addition, arrows in the figures may schematically depict process steps that convey streams from one system component to another system component. For example, an arrow pointing from one system component to another system component may represent "transferring" a system component effluent to another system component, which may include "leaving" or "removing" the contents of a process stream from one system component, and "introducing" the contents of that product stream to another system component.

[0019] It should be understood that when two or more lines are Figure 1-3 Two or more process streams are "mixed" or "combined" when they intersect in a schematic flow diagram of FIG. Mixing or combining can also include mixing by introducing the two streams directly into a similar reactor, separation equipment, or other system component. For example, it should be understood that when two streams are depicted as being combined directly before entering a separation unit or reactor, in some embodiments, the streams may be equivalent to being introduced into the separation unit or reactor and mixed in the reactor.

[0020] Reference will now be made in more detail to various embodiments, some of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. DETAILED DESCRIPTION

[0021] The present disclosure relates to systems and methods for upgrading naphtha to produce more valuable chemical intermediates such as olefins and aromatic compounds. Figure 1, schematically depicts an embodiment of a system 100 for upgrading a naphtha feed stream 101. The system 100 includes an adsorption unit 110, a splitting unit 130, a steam cracking unit 120, an aromatization unit 140, a reforming unit 150, and a separation unit 160. The adsorption unit 110 is located upstream of and fluidly connected to the splitting unit 130 and the steam cracking unit 120. The steam cracking unit 120 is located downstream of and fluidly connected to the adsorption unit 110, and the steam cracking unit 120 is located upstream of and fluidly connected to the separation unit 160. The splitting unit 130 is located downstream of and fluidly connected to the adsorption unit 110, and the splitting unit 130 is located upstream of and fluidly connected to both the aromatization unit 140 and the reforming unit 150, respectively. The aromatization unit 140 is located downstream of the splitting unit 130 and is fluidly connected to the splitting unit 130, and the aromatization unit is located upstream of the separation unit 160 and is fluidly connected to the separation unit 160. The reforming unit 150 is located downstream of the splitting unit 130 and is fluidly connected to the splitting unit 130, and the reforming unit is located upstream of the separation unit 160 and is fluidly connected to the separation unit 160. The separation unit 160 is located downstream of both the aromatization unit 140 and the reforming unit 150 and is fluidly connected to the aromatization unit 140 and the reforming unit 150, respectively, and the separation unit is fluidly connected to the steam cracking unit 120.

[0022] Now I will refer to Figure 1A method for reforming naphtha into benzene, toluene, xylenes (BTX) and olefins using system 100 is described. A feed stream naphtha containing naphtha is introduced into an adsorption unit 110, in which normal paraffins are separated from isoparaffins. A normal paraffin stream 102 leaves the adsorption unit 110 and is introduced into a steam cracking unit 120. An isoparaffin stream 103 leaves the adsorption unit 110 and is introduced into a splitting unit 130. As described above, the normal paraffin stream 102 is introduced into the steam cracking unit 120, in which the normal paraffin stream is converted into a first BTX and olefin stream 108. The first BTX and olefin stream 108 can then be used in additional chemical processes. The isoparaffin stream 103 leaving the adsorption unit 110 is introduced into a splitting unit 130, in which the isoparaffin stream 103 is split into a lower boiling point isoparaffin stream 104 and a higher boiling point isoparaffin stream 105. The lower boiling isoparaffin stream 104 leaves the splitting unit 130 and is introduced into the aromatization unit 140, where the isoparaffins in the lower boiling isoparaffin stream 104 are converted to BTX and olefins. The aromatized stream 106 leaves the aromatization unit 140 and is introduced into the separation unit 160. The higher boiling isoparaffin stream 105 leaves the splitting unit 130 and is introduced into the reforming unit 150, where the isoparaffins in the higher boiling isoparaffin stream are reformed into BTX and olefins. The reformed stream 107 leaves the reforming unit 150 and is introduced into the separation unit 160. In the separation unit 160, the aromatized stream 106 and the reformed stream 107 are combined, and the BTX and olefins from the aromatized stream 106 and the BTX and olefins from the reformed stream 107 are separated from the other components in the aromatized stream 106 and the other components from the reformed stream 107. BTX and olefins from the aromatization stream 106 and BTX and olefins from the reforming stream 107 leave the separation unit as a second BTX and olefin stream 109. The second BTX and olefin stream 109 can then be used in additional chemical processes. Other components from the aromatization stream 106 and other components from the reforming stream 107 leave the separation unit 160 as a raffinate stream 111 and are introduced into the steam cracking unit 120. In the steam cracking unit 120, the raffinate stream 111 is combined with the normal paraffin stream 102 and converted into BTX and olefins.

[0023] The systems and methods of the present disclosure improve the conversion of naphtha to olefins and aromatics through steam cracking and reforming. The systems and methods of the present disclosure separate normal paraffins from isoparaffins from a naphtha feed stream before introducing the stream into a steam cracking unit. As described above, normal paraffins have been found to be a preferred feed over isoparaffins. Therefore, by separating normal paraffins from isoparaffins in a naphtha feed stream and introducing the normal paraffin-rich stream into a steam cracking unit, an increase in the yield of olefins, aromatics, or both in naphtha can be achieved, as well as other features, compared to other steam cracking processes.

[0024] As used in the present disclosure, "separation unit" or "splitting unit" refers to any separation device that separates one or more chemicals in a mixture at least partially from each other. For example, a separation unit or splitting unit can selectively separate different chemical substances from each other to form one or more chemical fractions. Examples of separation units or splitting units include, but are not limited to, distillation towers, fractionators, flash tanks, buffer tanks, buffer pots, centrifuges, filtration equipment, traps, scrubbers, expansion equipment, membranes, solvent extraction equipment, high-pressure separators, low-pressure separators, and the like. It should be understood that the separation or splitting process described in the present disclosure may not completely separate all of one chemical component from all of another chemical component. It should be understood that the separation or splitting process described in the present disclosure "at least partially" separates different chemical components from each other, and even if it is not explicitly stated, it should be understood that the separation or splitting may include only partial separation. As used in the present disclosure, one or more chemical components can be "separated" or "split" from a process stream to form a new process stream. Generally, a process stream can enter a separation unit or splitting unit and be divided or separated into two or more process streams with a desired composition.

[0025] As used in this disclosure, the term "fractionation" may refer to a process of separating one or more components of a composition in which the components separate from each other during a phase change based on differences in the properties of each component. For example, as used in this disclosure, "distillation" refers to separating the components of a liquid composition based on differences in the boiling temperatures of the components of the composition.

[0026] In addition, in some separation processes, a "lower boiling point" effluent and a "higher boiling point" effluent may leave a separation unit or splitting unit, respectively. In general, the lower boiling point effluent has a lower boiling point temperature than the higher boiling point effluent. Some separation systems can produce a "medium boiling point effluent" that may include components with boiling point temperatures between the lower boiling point effluent and the higher boiling point effluent. The medium boiling point effluent may be referred to as an intermediate distillate. Some separation systems are operable to produce multiple streams, each having a different boiling point range. It should be further understood that in the case where only one separation unit is shown or described in the figure, two or more separation units may be used to perform the same or substantially the same separation. For example, in the case of describing a distillation tower with multiple outlets, it is envisioned that several separators arranged in series are able to equally separate the feed streams, and such embodiments are within the scope of the embodiments currently described.

[0027] As used in this disclosure, the terms "upstream" and "downstream" may refer to the relative positioning of a unit operation with respect to the flow direction of a process stream. A first unit operation of a system may be considered "upstream" of a second unit operation if a process stream flowing through the system encounters the first unit operation before encountering the second unit operation. Similarly, a second unit operation may be considered "downstream" of the first unit operation if a process stream flowing through the system encounters the first unit operation before encountering the second unit operation.

[0028] As used in this disclosure, transferring a stream or effluent from one unit "directly" to another unit may refer to transferring a stream or effluent from a first unit to a second unit without passing the stream or effluent through an intervening reaction system or separation system that substantially changes the composition of the stream or effluent. Heat transfer equipment, such as heat exchangers, preheaters, coolers, condensers, or other heat transfer equipment, and pressure equipment, such as pumps, pressure regulators, compressors, or other pressure equipment, are not considered to be intervening systems that change the composition of a stream or effluent. Combining two streams or effluents together is also not considered to include an intervening system that changes the composition of one or both of the combined streams or effluents.

[0029] As used in the present disclosure, the term "effluent" can refer to a stream that emanates from a reactor, a reaction zone, or a separation unit after a particular reaction or separation. Generally, the effluent has a composition different from the stream that enters the separation unit, the reactor, or the reaction zone. It should be understood that when the effluent is transferred to another system unit, only a portion of the system stream can be transferred. For example, a slipstream can carry away some of the effluent, which means that only a portion of the effluent can enter a downstream system unit. The term "reaction effluent" can be more specifically used to refer to a stream that emanates from a reactor or a reaction zone.

[0030] As used herein, "fixed bed" (particularly with respect to an adsorption zone) refers to an absorbent bed within the adsorption zone that is not displaced by fluid entering and leaving the adsorption zone, ie, the adsorbent remains in place.

[0031] As used in this disclosure, "cracking" generally refers to a chemical reaction in which a molecule having a carbon-carbon bond is broken into more than one molecule by breaking one or more of the carbon-carbon bonds; in which a compound including a cyclic portion, such as an aromatic compound, is converted into a compound that does not include a cyclic portion; or in which a molecule having a carbon-carbon double bond is reduced to a carbon-carbon single bond. Some catalysts may have multiple forms of catalytic activity, and referring to a catalyst by one particular function does not render the catalyst inactive for other functions. As used throughout this disclosure, "hydrocracking" may refer to the catalytic cracking of hydrocarbons in the presence of hydrogen.

[0032] As used throughout this disclosure, the term "butene" refers to one or more of 1-butene, trans-2-butene, cis-2-butene, isobutylene, or a mixture of these isomers. As used throughout this disclosure, the term "n-butene" may refer to one or more of 1-butene, trans-2-butene, cis-2-butene, or a mixture of these isomers, and does not include isobutylene. As used throughout this disclosure, the term "2-butene" may refer to trans-2-butene, cis-2-butene, or a mixture of these two isomers.

[0033] As used throughout this disclosure, the term "xylene", when used without specifying the isomer, such as the prefix p, m or o (or the letters p, m and o, respectively), may refer to one or more of m-xylene, o-xylene, p-xylene and mixtures of these xylene isomers.

[0034] As used throughout this disclosure, the term "naphtha" may refer to a mixture of many different hydrocarbons. It has an initial boiling point (IBP) of about 35°C, a final boiling point (FBP) of about 200°C, and contains paraffins, cycloparaffins (cyclic paraffins), and aromatics ranging from 4 carbon atoms to about 10 or 11 carbon atoms.

[0035] It should be further understood that a stream can be named after a component of the stream, and the component of the named stream can be the major component of the stream (e.g., comprising 50 wt.%, 70 wt.%, 90 wt.%, 95 wt.%, 99 wt.%, 99.5 wt.%, or even 99.9 wt.% to 100 wt.% of the contents of the stream). It should also be understood that when a stream including the component is disclosed as being transferred from one system component to another system component, the component of the stream is disclosed as being transferred from the system component to the other system component. For example, a "hydrogen stream" disclosed as being transferred to a first system component or from a first system component to a second system component should be understood to be equivalently disclosed as being transferred to the first system component or from a first system component to a second system component.

[0036] Refer again Figure 1, a naphtha feed stream 101 is introduced into an adsorption unit 110. In one or more embodiments, the naphtha feed stream 101 can be an overhead distillate from a crude distillation tower, hydrocracking, fluid catalytic cracking (FCC) or coking, and contains normal paraffins and isoparaffins. In an embodiment, the naphtha feed stream contains other components, such as aromatics and olefins. The adsorption unit 110 is operable to separate normal paraffins from isoparaffins present in the naphtha feed stream 101. According to an embodiment, the naphtha feed stream 101 contains 50wt% to 80wt% of paraffins (including both normal paraffins and isoparaffins), for example, 55wt% to 75wt% or 60wt% to 70wt%. The molar ratio of iso-paraffins to normal-paraffins in the naphtha feed stream 101 is from 0.8 to 5.0, eg, from 1.0 to 4.5, from 1.5 to 4.0, from 2.0 to 3.5, or from 2.0 to 3.0.

[0037] Now refer to Figure 2 The embodiment of the adsorption unit 110 is described in more detail. In the embodiment, the adsorption unit 110 includes a plurality of adsorption zones 110a and 110b. For ease of illustration and description, the adsorption unit 110 is Figure 2 110a and 110b. However, the adsorption unit 110 may have more than or equal to two adsorption zones, such as 2, 3, 4, 5, 6, 7, 8 adsorption zones or more than 8 adsorption zones. In an embodiment, each adsorption zone is a fixed bed adsorption zone filled with an adsorbent. The naphtha feed stream 101 is fed into the first adsorption zone 110a at the bottom as the first naphtha feed stream 101a. Since the naphtha fills the first adsorption zone 110a, the normal paraffins are adsorbed by the adsorbent filled in the first adsorption zone 110a, and the isoparaffins and other components in the first naphtha feed stream 101a pass through the first adsorption zone 110a and leave the first adsorption zone 110a as the first isoparaffin stream 103a. The first naphtha feed stream 101a continues to flow to the first adsorption zone 110a until the adsorbent loaded into the first adsorption zone 110a is saturated with normal paraffins.

[0038] Once the adsorbent loaded into the first adsorption zone 110a is saturated with normal paraffins, the naphtha feed stream 101 is bypassed through the first adsorption zone 110a, for example, through a valve, etc., and the naphtha feed stream 101 is sent to the second adsorption zone 110b through the second naphtha feed stream 101b. Since the naphtha fills the second adsorption zone 110b, the normal paraffins are adsorbed by the adsorbent filled in the second adsorption zone 110b, and the isoparaffins and other components in the second naphtha feed stream 101b pass through the second adsorption zone 110b and leave the second adsorption zone 110b as the second isoparaffin stream 103b. The second naphtha feed stream 101b continues to flow to the second adsorption zone 110b until the adsorbent loaded into the second adsorption zone 110b is saturated with normal paraffins.

[0039] In an embodiment, the saturated adsorbent in the first adsorption zone 110a is regenerated by feeding a desorbent into the first adsorption zone 110a. In the process, the naphtha feed stream 101 is directed to the second adsorption zone 110b through the second naphtha feed stream 101b, and the naphtha feed stream 101 is not fed into the first adsorption zone 110a. In an embodiment, a desorbent is added to the top of the first adsorption zone 110a through a first desorbent stream 201a, in which the desorbent desorbs normal paraffins from the adsorbent in the first adsorption zone 110a. The desorbed bottom sediment contains normal paraffins and desorbent. The desorbent in the desorbed bottom sediment is flushed and recycled to be used again in the first desorbent stream 201a. The normal paraffins in the desorbed bottom sediment leave the bottom of the first adsorption zone 110a as the first normal paraffin stream 102a.

[0040] In an embodiment, the saturated adsorbent in the second adsorption zone 110b is regenerated by feeding a desorbent into the second adsorption zone 110b. In the process, the naphtha feed stream 101 is directed to the first adsorption zone 110a through the first naphtha feed stream 101a, and the naphtha feed stream 101 is not fed into the second adsorption zone 110b. In an embodiment, a desorbent is added to the top of the second adsorption zone 110b through a second desorbent stream 201b, in which the desorbent desorbs normal paraffins from the adsorbent in the second adsorption zone 110b. The desorbed bottom sediment contains normal paraffins and desorbent. The desorbent in the desorbed bottom sediment is flushed and recycled to be used again in the second desorbent stream 201b. The normal paraffins in the desorbed bottom sediment leave the bottom of the second adsorption zone 110b as a second normal paraffin stream 102b.

[0041] It should be understood that in embodiments, any number of adsorption zones may be included in the adsorption unit 110, and in embodiments where three or more adsorption zones are present in the adsorption unit 110, the naphtha feed stream 101 may be introduced into multiple adsorption zones simultaneously. Similarly, in embodiments where three or more adsorption zones are present in the adsorption unit 110, regeneration using a desorbent may be performed simultaneously in more than one adsorption zone. The process conditions for the adsorption and regeneration processes are described in more detail below. It should be understood that these process conditions apply to both the first adsorption zone 110a and the second adsorption zone 110b, as well as any number of other adsorption zones present in the adsorption unit 110.

[0042] In one or more embodiments, the adsorbent is zeolite A as described by the International Zeolite Association (IZA). Generally, but not limited to, zeolite A is a zeolite having the formula [Na + 12 (H2O) 27 ]8[Al 12 Si 22 O 48 ]8 aluminosilicate, and having sodalite cages connected by four-membered rings forming a three-dimensional network. Sodium can be replaced with lithium, potassium or calcium to change the size of the ring openings, thereby changing the adsorption properties of the zeolite A adsorbent. In an embodiment, the adsorbent is zeolite 5A as defined by IZA. Zeolite 5A is typically, but is not limited to, a calcium-based zeolite A structure with a ring opening of approximately 5 angstroms. or 0.5nm. Therefore, zeolite 5A generally absorbs less than molecules. In embodiments, the adsorbent may be zeolite T, chabazite, or erionite as described in U.S. Patent No. 2,950,952. In embodiments, the adsorbent may be provided in the form of particles loaded into the adsorption zone. In embodiments, the particles may have an average size of 1 mm to 7 mm, wherein the size is measured along the longest axis of the particles. In embodiments, the particles may have an average size of 2 mm to 7 mm, 3 mm to 7 mm, 4 mm to 7 mm, 5 mm to 7 mm, 6 mm to 7 mm, 1 mm to 6 mm, 2 mm to 6 mm, 3 mm to 6 mm, 4 mm to 6 mm, 5 mm to 6 mm, 1 mm to 5 mm, 2 mm to 5 mm, 3 mm to 5 mm, 4 mm to 5 mm, 1 mm to 4 mm, 2 mm to 4 mm, 3 mm to 4 mm, 1 mm to 3 mm, 2 mm to 3 mm, or 1 mm to 2 mm.

[0043] In embodiments, the adsorbent is dried in nitrogen or atmospheric air at a temperature of 350°C to 550°C for a duration of 2 hours to 12 hours prior to exposing the adsorbent to the naphtha feed stream 101. In one or more embodiments, the adsorbent is dried at a temperature of 375°C to 550°C, 400°C to 550°C, 425°C to 550°C, 450°C to 550°C, 475°C to 550°C, 500°C to 550°C, 525°C to 550°C, 350°C to 525°C, 375°C to 525°C, 400°C to 525°C, 425°C to 525°C, 450°C to 525°C, 475°C to 525°C, 500°C to 525°C, 350°C to 500°C, 375°C to 500°C, 400°C to 500°C, The present invention is preferably dried at a temperature of 425°C to 500°C, 450°C to 500°C, 475°C to 500°C, 350°C to 475°C, 375°C to 475°C, 400°C to 475°C, 425°C to 475°C, 450°C to 475°C, 350°C to 450°C, 375°C to 450°C, 400°C to 450°C, 425°C to 450°C, 350°C to 425°C, 375°C to 425°C, 400°C to 425°C, 350°C to 400°C, 375°C to 400°C or 350°C to 375°C. In embodiments, the adsorbent is dried for a period of 4 hours to 12 hours, 6 hours to 12 hours, 8 hours to 12 hours, 10 hours to 12 hours, 2 hours to 10 hours, 4 hours to 10 hours, 6 hours to 10 hours, 8 hours to 10 hours, 2 hours to 8 hours, 4 hours to 8 hours, 6 hours to 8 hours, 2 hours to 6 hours, 4 hours to 6 hours, or 2 hours to 4 hours.

[0044] During the adsorption process, when the n-paraffin is being adsorbed by the adsorbent in the adsorption zone, according to embodiments, the adsorption zone is operated at atmospheric pressure and a temperature of 100° C. to 300° C. In embodiments, the temperature during the adsorption process is 125° C. to 300° C., 150° C. to 300° C., 175° C. to 300° C., 200° C. to 300° C., 225° C. to 300° C., 250° C. to 300° C., 275° C. to 300° C., 100° C. to 275° C., 125° C. to 275° C., 150° C. to 275° C., 175° C. to 275° C., 200° C. to 275° C., 225° C. to 275° C., 250° C. to 275° C., 100° C. to 250° C., 125° C. to 250° C., 150° C. to 250° C. 0°C, 175°C to 250°C, 200°C to 250°C, 225°C to 250°C, 100°C to 225°C, 125°C to 225°C, 150°C to 225°C, 175°C to 225°C, 200°C to 225°C, 100°C to 200°C, 125°C to 200°C, 150°C to 200°C, 175°C to 200°C, 100°C to 175°C, 125°C to 175°C, 150°C to 175°C, 100°C to 150°C, 125°C to 150°C or 100°C to 125°C.

[0045] In one or more embodiments, during the adsorption process, the naphtha feed stream 101 is fed at a rate of 0.001 h -1 ) to 10h -1 The liquid hourly space velocity (LHSV) flows to the adsorption zone, for example 0.01h -1 Until 10h -1 , 0.1h -1 Until 10h -1 、0.5h -1 Until 10h -1 , 1h -1 Until 10h -1 , 2h -1 Until 10h -1 , 3h -1 Until 10h -1 , 4h -1 Until 10h -1 , 5h -1 Until 10h -1 , 6h -1 Until 10h -1 , 7h -1 Until 10h -1 , 8h -1 Until 10h -1 , 9h -1 Until 10h -1 、0.001h -1 Until 9h -1 , 0.01h -1 Until 9h-1 , 0.1h -1 Until 9h -1 、0.5h -1 Until 9h -1 , 1h -1 Until 9h -1 , 2h -1 Until 9h -1 , 3h -1 Until 9h -1 , 4h -1 Until 9h -1 , 5h -1 Until 9h -1 , 6h -1 Until 9h -1 , 7h -1 Until 9h -1 , 8h -1 Until 9h -1 、0.001h -1 Until 8h -1 , 0.01h -1 Until 8h -1 , 0.1h -1 Until 8h -1 、0.5h -1 Until 8h -1 , 1h -1 Until 8h -1 , 2h -1 Until 8h -1 , 3h -1 Until 8h -1 , 4h -1 Until 8h -1 , 5h -1 Until 8h -1 , 6h -1 Until 8h -1 , 7h -1 Until 8h -1 、0.001h -1 Until 7h -1 , 0.01h -1 Until 7h -1 , 0.1h -1 Until 7h -1 、0.5h -1 Until 7h -1 , 1h -1 Until 7h -1 , 2h -1 Until 7h -1 , 3h -1 Until 7h -1 , 4h -1 Until 7h -1 , 5h -1 Until 7h -1 , 6h-1 Until 7h -1 、0.001h -1 Until 6h -1 , 0.01h -1 Until 6h -1 , 0.1h -1 Until 6h -1 、0.5h -1 Until 6h -1 , 1h -1 Until 6h -1 , 2h -1 Until 6h -1 , 3h -1 Until 6h -1 , 4h -1 Until 6h -1 , 5h -1 Until 6h -1 、0.001h -1 Until 5h -1 , 0.01h -1 Until 5h -1 , 0.1h -1 Until 5h -1 、0.5h -1 Until 5h -1 , 1h -1 Until 5h -1 , 2h -1 Until 5h -1 , 3h -1 Until 5h -1 , 4h -1 Until 5h -1 、0.001h -1 Up to 4h -1 , 0.01h -1 Up to 4h -1 , 0.1h -1 Up to 4h -1 、0.5h -1 Up to 4h -1 , 1h -1 Up to 4h -1 , 2h -1 Up to 4h -1 , 3h -1 Up to 4h -1 、0.001h -1 Until 3h -1 , 0.01h -1 Until 3h -1 , 0.1h -1 Until 3h -1 、0.5h -1 Until 3h -1 , 1h -1 Until 3h -1, 2h -1 Until 3h -1 、0.001h -1 Up to 2h -1 , 0.01h -1 Up to 2h -1 , 0.1h -1 Up to 2h -1 、0.5h -1 Up to 2h -1 , 1h -1 Up to 2h -1 、0.001h -1 Up to 1h -1 , 0.01h -1 Up to 1h -1 , 0.1h -1 Up to 1h -1 、0.5h -1 Up to 1h -1 、0.001h -1 Up to 0.5h -1 , 0.01h -1 Up to 0.5h -1 , 0.1h -1 Up to 0.5h -1 、0.001h -1 To 0.1h -1 , 0.01h -1 To 0.1h -1 or 0.001h -1 To 0.01h -1 .

[0046] In one or more embodiments, the isoparaffin stream 103 exiting the adsorption unit comprises at least 95 wt.% isoparaffins, e.g., at least 95.5 wt.% isoparaffins, at least 96.0 wt.% isoparaffins, at least 96.5 wt.% isoparaffins, at least 97.0 wt.% isoparaffins, at least 97.5 wt.% isoparaffins, at least 98.0 wt.% isoparaffins, at least 98.5 wt.% isoparaffins, at least 99.0 wt.% isoparaffins, or at least 99.5 wt.% isoparaffins. In embodiments, the isoparaffin stream 103 exiting the adsorption unit comprises from 95.0 wt.% to 99.5 wt.% isoparaffins, e.g., from 95.5 wt.% to 99.5 wt.% isoparaffins, from 96.0 wt.% to 99.5 wt.% isoparaffins, from 96.5 wt.% to 99.5 wt.% isoparaffins, from 97.0 wt.% to 99.5 wt.% isoparaffins, from 97.5 wt.% to 99.5 wt.% isoparaffins, from 98.0 wt.% to 99.5 wt.% isoparaffins, from 98.5 wt.% to 99.5 wt.% isoparaffins. .% isoparaffins, 99.0wt.% to 99.5wt.% isoparaffins, 95.0wt.% to 99.0wt.% isoparaffins, 95.5wt.% to 99.0wt.% isoparaffins, 96.0wt.% to 99.0wt.% isoparaffins, 96.5wt.% to 99.0wt.% isoparaffins, 97.0wt.% to 99.0wt.% isoparaffins, 97.5wt.% to 99.0wt.% isoparaffins, 98.0wt.% to 99.0wt.% isoparaffins, 98.5wt.% to 99 .0wt.% isoparaffin, 95.0wt.% to 98.5wt.% isoparaffin, 95.5wt.% to 98.5wt.% isoparaffin, 96.0wt.% to 98.5wt.% isoparaffin, 96.5wt.% to 98.5wt.% isoparaffin, 97.0wt.% to 98.5wt.% isoparaffin, 97.5wt.% to 98.5wt.% isoparaffin, 98.0wt.% to 98.5wt.% isoparaffin, 95.0wt.% to 98.0wt.% isoparaffin, 95.5wt. % to 98.0 wt. % of isoparaffins, 96.0 wt. % to 98.0 wt. % of isoparaffins, 96.5 wt. % to 98.0 wt. % of isoparaffins, 97.0 wt. % to 98.0 wt. % of isoparaffins, 97.5 wt. % to 98.0 wt. % of isoparaffins, 95.0 wt. % to 97.5 wt. % of isoparaffins, 95.5 wt. % to 97.5 wt. % of isoparaffins, 96.0 wt. % to 97.5 wt. % of isoparaffins, 96.5 wt. % to 97.5 wt. % of isoparaffins, 97.0 wt.% to 97.5 wt.% isoparaffin, 95.0 wt.% to 97.0 wt.% isoparaffin, 95.5 wt.% to 97.0 wt.% isoparaffin, 96.0 wt.% to 97.0 wt.% isoparaffin, 96.5 wt.% to 97.0 wt.% isoparaffin, 95.0 wt.% to 96.5 wt.% isoparaffin, 95.5 wt.% to 96.5 wt.% isoparaffin, 96.0 wt.% to 96.5 wt.% isoparaffin, 95.0 wt.% to 96.0 wt.% isoparaffin, 95.5 wt.% to 96.0 wt.% isoparaffin or 95.0 wt.% to 95.5 wt.% isoparaffin.

[0047] After the adsorbent is saturated with normal paraffins, the flow of the naphtha feed stream 101 to the adsorption zone with the saturated adsorbent is interrupted, and a stream of desorbent is introduced into the adsorption zone to regenerate the adsorbent. In embodiments, the desorbent used to regenerate the adsorbent is selected from normal pentane or hexane. In one or more embodiments, the desorbent is normal pentane.

[0048] During the regeneration process, the n-paraffins in the adsorbent are desorbed by the desorbent in the adsorption zone, and according to embodiments, the adsorption zone is operated at atmospheric pressure and a temperature of 100° C. to 300° C. In embodiments, the temperature during the regeneration process is 125° C. to 300° C., 150° C. to 300° C., 175° C. to 300° C., 200° C. to 300° C., 225° C. to 300° C., 250° C. to 300° C., 275° C. to 300° C., 100° C. to 275° C., 125° C. to 275° C., 150° C. to 275° C., 175° C. to 275° C., 200° C. to 275° C., 225° C. to 275° C., 250° C. to 275° C., 100° C. to 250° C., 125° C. to 250° C., 150° C. to 250° C. 0°C, 175°C to 250°C, 200°C to 250°C, 225°C to 250°C, 100°C to 225°C, 125°C to 225°C, 150°C to 225°C, 175°C to 225°C, 200°C to 225°C, 100°C to 200°C, 125°C to 200°C, 150°C to 200°C, 175°C to 200°C, 100°C to 175°C, 125°C to 175°C, 150°C to 175°C, 100°C to 150°C, 125°C to 150°C or 100°C to 125°C.

[0049] In one or more embodiments, during the adsorption process, the first desorbent stream 201a or 201b is heated at 10.0 h. -1 To 20.0h -1 The LHSV flows to the adsorption zone, for example 11.0h -1 To 20.0h -1 , 12.0h -1To 20.0h -1 , 13.0h -1 To 20.0h -1 , 14.0h -1 To 20.0h -1 , 15.0h -1 To 20.0h -1 , 16.0h -1 To 20.0h -1 , 17.0h -1 To 20.0h -1 , 18.0h -1 To 20.0h -1 , 19.0h -1 To 20.0h -1 , 10.0h -1 Until 19.0h -1 , 11.0h -1 Until 19.0h -1 , 12.0h -1 Until 19.0h -1 , 13.0h -1 Until 19.0h -1 , 14.0h -1 Until 19.0h -1 , 15.0h -1 Until 19.0h -1 , 16.0h -1 Until 19.0h -1 , 17.0h -1 Until 19.0h -1 , 18.0h -1 Until 19.0h -1 , 10.0h -1 Until 18.0h -1 , 11.0h -1 Until 18.0h -1 , 12.0h -1 Until 18.0h -1 , 13.0h -1 Until 18.0h -1 , 14.0h -1 Until 18.0h -1 , 15.0h -1 Until 18.0h -1 , 16.0h -1 Until 18.0h -1 , 17.0h -1 Until 18.0h -1 , 10.0h -1 Until 17.0h -1 , 11.0h -1 Until 17.0h-1 , 12.0h -1 Until 17.0h -1 , 13.0h -1 Until 17.0h -1 , 14.0h -1 Until 17.0h -1 , 15.0h -1 Until 17.0h -1 , 16.0h -1 Until 17.0h -1 , 10.0h -1 Until 16.0h -1 , 11.0h -1 Until 16.0h -1 , 12.0h -1 Until 16.0h -1 , 13.0h -1 Until 16.0h -1 , 14.0h -1 Until 16.0h -1 , 15.0h -1 Until 16.0h -1 , 10.0h -1 To 15.0h -1 , 11.0h -1 To 15.0h -1 , 12.0h -1 To 15.0h -1 , 13.0h -1 To 15.0h -1 , 14.0h -1 To 15.0h -1 , 10.0h -1 Until 14.0h -1 , 11.0h -1 Until 14.0h -1 , 12.0h -1 Until 14.0h -1 , 13.0h -1 Until 14.0h -1 , 10.0h -1 Until 13.0h -1 , 11.0h -1 Until 13.0h -1 , 12.0h -1 Until 13.0h -1 , 10.0h -1 Until 12.0h -1 , 11.0h -1 Until 12.0h -1 or 10.0h -1 Until 11.0h -1 .

[0050] In an embodiment, a desorption bottom sediment rich in normal paraffins is collected at the bottom of the adsorption zone that has been regenerated. A desorbent (such as normal pentane or hexane) is flushed from the desorption bottom sediment and recycled to the adsorption zone as a first desorbent stream 201a or a second desorbent stream 201b. In one or more embodiments, the desorbent is separated from the normal paraffins by distillation. The normal paraffins then leave the adsorption unit 110 as a normal paraffin stream 102.

[0051] In one or more embodiments, the normal paraffin stream 102 exiting the adsorption unit comprises at least 95 wt.% normal paraffins, e.g., at least 95.5 wt.% normal paraffins, at least 96.0 wt.% normal paraffins, at least 96.5 wt.% normal paraffins, at least 97.0 wt.% normal paraffins, at least 97.5 wt.% normal paraffins, at least 98.0 wt.% normal paraffins, at least 98.5 wt.% normal paraffins, at least 99.0 wt.% normal paraffins, or at least 99.5 wt.% normal paraffins. In embodiments, the normal paraffin stream 102 exiting the adsorption unit comprises 95.0 wt.% to 99.5 wt.% normal paraffins, e.g., 95.5 wt.% to 99.5 wt.% normal paraffins, 96.0 wt.% to 99.5 wt.% normal paraffins, 96.5 wt.% to 99.5 wt.% normal paraffins, 97.0 wt.% to 99.5 wt.% normal paraffins, 97.5 wt.% to 99.5 wt.% normal paraffins, 98.0 wt.% to 99.5 wt.% normal paraffins, 98.5 wt.% to 99.5 wt.% normal paraffins. .% of normal paraffins, 99.0wt.% to 99.5wt.% of normal paraffins, 95.0wt.% to 99.0wt.% of normal paraffins, 95.5wt.% to 99.0wt.% of normal paraffins, 96.0wt.% to 99.0wt.% of normal paraffins, 96.5wt.% to 99.0wt.% of normal paraffins, 97.0wt.% to 99.0wt.% of normal paraffins, 97.5wt.% to 99.0wt.% of normal paraffins, 98.0wt.% to 99.0wt.% of normal paraffins, 98.5wt.% to 99 .0wt.% of normal paraffins, 95.0wt.% to 98.5wt.% of normal paraffins, 95.5wt.% to 98.5wt.% of normal paraffins, 96.0wt.% to 98.5wt.% of normal paraffins, 96.5wt.% to 98.5wt.% of normal paraffins, 97.0wt.% to 98.5wt.% of normal paraffins, 97.5wt.% to 98.5wt.% of normal paraffins, 98.0wt.% to 98.5wt.% of normal paraffins, 95.0wt.% to 98.0wt.% of normal paraffins, 95.5wt. % to 98.0wt.% of normal paraffins, 96.0wt.% to 98.0wt.% of normal paraffins, 96.5wt.% to 98.0wt.% of normal paraffins, 97.0wt.% to 98.0wt.% of normal paraffins, 97.5wt.% to 98.0wt.% of normal paraffins, 95.0wt.% to 97.5wt.% of normal paraffins, 95.5wt.% to 97.5wt.% of normal paraffins, 96.0wt.% to 97.5wt.% of normal paraffins, 96.5wt.% to 97.5wt.% of normal paraffins, 97.0wt.% to 97.5wt.% of normal paraffins, 95.0wt.% to 97.0wt.% of normal paraffins, 95.5wt.% to 97.0wt.% of normal paraffins, 96.0wt.% to 97.0wt.% of normal paraffins, 96.5wt.% to 97.0wt.% of normal paraffins, 95.0wt.% to 96.5wt.% of normal paraffins, 95.5wt.% to 96.5wt.% of normal paraffins, 96.0wt.% to 96.5wt.% of normal paraffins, 95.0wt.% to 96.0wt.% of normal paraffins, 95.5wt.% to 96.0wt.% of normal paraffins, or 95.0wt.% to 95.5wt.% of normal paraffins.

[0052] Reference again Figure 2 , the isoparaffin stream 103 and the normal paraffin stream 102 leave the adsorption unit as effluents. It should be understood that at any given time, the isoparaffin stream 103 leaving the adsorption unit 110 comprises the first isoparaffin stream 103a from the first adsorption zone 110a, the second isoparaffin stream 103b from the second adsorption zone 110b, or a combination of the first isoparaffin stream 103a and the second isoparaffin stream 103b. Similarly, in embodiments, at any given time, the normal paraffin stream 102 leaving the adsorption unit 110 comprises the first normal paraffin stream 102a from the first adsorption zone 110a, the second normal paraffin stream 102b from the second adsorption zone 110b, or a combination of the first normal paraffin stream 102a and the second normal paraffin stream 102b.

[0053] Reference again Figure 1 , the normal paraffin stream 102 leaves the adsorption unit 110 and is transferred to the steam cracking unit 120. Now referring to Figure 3 The steam cracking unit 120 is operable to contact the normal paraffin stream 102 with steam 112 at a temperature sufficient to cause at least a portion of the hydrocarbons in the normal paraffin stream to undergo a hydrocracking reaction to produce a first BTX and olefin stream 108, wherein the first BTX and olefin stream includes an increased concentration of olefins, aromatic compounds, or both.

[0054] The steam cracking unit 120 may include a convection zone 121 and a pyrolysis zone 122. The normal paraffin stream 102 may be passed to the convection zone 121 along with steam 112. In an embodiment, a raffinate stream 111 (discussed in more detail below) is introduced into the convection zone 121. In the convection zone 121, the normal paraffin stream may be preheated to a desired temperature, such as 400°C to 650°C. The contents of the normal paraffin stream 102 present in the convection zone 121 may then be passed to the pyrolysis zone 122, where the contents are steam cracked to produce a first BTX and olefin stream 108. The first BTX and olefin stream 108 may leave the steam cracking unit 120 and pass through a heat exchanger (not shown) in which a process fluid such as water or pyrolysis fuel oil cools the first BTX and olefin stream 108. The first BTX and olefin stream 108 may include a mixture of cracked hydrocarbon-based materials that may be separated into one or more petrochemical products included in one or more system product streams. The pyrolysis zone 122 may be operated at a temperature of 700° C. to 900° C. The pyrolysis zone 122 may be operated with a residence time of 0.05 seconds to 2 seconds. The mass ratio of steam 112 to normal paraffin stream 102 may be about 0.3:1 to about 2:1.

[0055] By providing the normal paraffin stream 102 to the steam cracking unit 120 instead of the naphtha feed stream 101, the ethylene yield can be increased by at least 15 wt.%, such as at least 20 wt.% or at least 25 wt.%; the total olefin yield is increased by at least 6 wt.%, at least 8 wt.% or at least 10 wt.%; and the N+2A in the separated naphtha is increased by at least 15 wt.%, at least 18 wt.% or at least 20 wt.%. The aromatic yield is also increased.

[0056] Reference again Figure 1 , the isoparaffin stream 103 leaves the adsorption unit 110 and is introduced into the splitting unit 130. In the splitting unit 130, the isoparaffin stream 103 is split into a lower boiling point isoparaffin stream 104 and a higher boiling point isoparaffin stream 105. The lower boiling point isoparaffin stream 104 contains isoparaffins having a boiling point below 65° C. The higher boiling point isoparaffin stream 105 contains isoparaffins, naphthalene, and aromatics having a boiling point of 65° C. to 180° C.

[0057] In embodiments, the higher boiling isoparaffin stream 105 comprises 40 wt% to 60 wt% isoparaffins, e.g., 42 wt% to 60 wt% isoparaffins, 45 wt% to 60 wt% isoparaffins, 48 ​​wt% to 60 wt% isoparaffins, 50 wt% to 60 wt% isoparaffins, 52 wt% to 60 wt% isoparaffins, 55 wt% to 60 wt% isoparaffins, 58 wt% to 60 wt% isoparaffins, , 40wt% to 58wt% isoparaffin, 42wt% to 58wt% isoparaffin, 45wt% to 58wt% isoparaffin, 48wt% to 58wt% isoparaffin, 50wt% to 58wt% isoparaffin, 52wt% to 58wt% isoparaffin, 55wt% to 58wt% isoparaffin, 40wt% to 55wt% isoparaffin, 42wt% to 55wt% isoparaffin, 45wt% % to 55 wt % of isoparaffins, 48 ​​wt % to 55 wt % of isoparaffins, 50 wt % to 55 wt % of isoparaffins, 52 wt % to 55 wt % of isoparaffins, 40 wt % to 52 wt % of isoparaffins, 42 wt % to 52 wt % of isoparaffins, 45 wt % to 52 wt % of isoparaffins, 48 ​​wt % to 52 wt % of isoparaffins, 50 wt % to 52 wt % of isoparaffins, 40 wt % to 50 wt % of isoparaffins % to 48 wt % of isoparaffins, 40 wt % to 45 wt % of isoparaffins, 42 wt % to 45 wt % of isoparaffins, 42 wt % to 45 wt % of isoparaffins, or 40 wt % to 42 wt % of isoparaffins.

[0058] In embodiments, the higher boiling isoparaffin stream 105 comprises from 35 wt% to 55 wt% naphthalene, e.g., from 38 wt% to 55 wt% naphthalene, from 40 wt% to 55 wt% naphthalene, from 42 wt% to 55 wt% naphthalene, from 45 wt% to 55 wt% naphthalene, from 48 wt% to 55 wt% naphthalene, from 50 wt% to 55 wt% naphthalene, from 52 wt% to 55 wt% naphthalene, from 35 wt% to 52 wt% naphthalene, from 38 wt% to 52 wt% naphthalene, from 40 wt% to 52 wt% naphthalene, from 42 wt% to 52 wt% naphthalene, from 45 wt% to 52 wt% naphthalene, from 48 wt% to 52 wt% naphthalene, from 50 wt% to 52 wt% naphthalene, from 35 wt% to 50 wt% naphthalene, from 38 wt% to 50 wt% naphthalene, from 40 wt% to 52 wt% naphthalene, from 42 wt% to 52 wt% naphthalene, % to 50wt% naphthalene, 42wt% to 50wt% naphthalene, 45wt% to 50wt% naphthalene, 48wt% to 50wt% naphthalene, 35wt% to 48wt% naphthalene, 38wt% to 48wt% naphthalene, 40wt% to 48wt% naphthalene, 42wt% to 48wt% naphthalene, 45wt% to 48wt% naphthalene, 35wt% to 45wt% naphthalene, 38wt% to 45wt% naphthalene, 40wt% to 45wt% naphthalene, 42wt% to 45wt% naphthalene, 35wt% to 42wt% naphthalene, 38wt% to 42wt% naphthalene, 40wt% to 42wt% naphthalene, 35wt% to 40wt% naphthalene, 38wt% to 40wt% naphthalene or 35wt% to 38wt% naphthalene.

[0059] In embodiments, the higher boiling isoparaffin stream 105 comprises from 5 wt% to 15 wt% aromatics, e.g., from 8 wt% to 15 wt% aromatics, from 10 wt% to 15 wt% aromatics, from 12 wt% to 15 wt% aromatics, from 5 wt% to 12 wt% aromatics, from 8 wt% to 12 wt% aromatics, from 10 wt% to 12 wt% aromatics, from 5 wt% to 10 wt% aromatics, from 8 wt% to 10 wt% aromatics, or from 5 wt% to 8 wt% aromatics.

[0060] In embodiments, the splitting unit 130 can be a distillation unit. However, in embodiments, any unit capable of splitting isoparaffins having a boiling point below 65°C from isoparaffins, naphthalene, and aromatics having a boiling point of 65°C to 180°C can be used. In one or more embodiments, the splitting unit 130 can be a conventional naphtha splitter having an inlet temperature of 100°C to 120°C, such as 105°C to 115°C or 105°C to 110°C.

[0061] The lower boiling isoparaffin stream 104 leaves the splitting unit 130 and is introduced into the aromatization unit 140. In the aromatization unit 140, the isoparaffins present in the lower boiling isoparaffin stream 104 are aromatized to increase the content of BTX and olefins, such as to increase the ethylene content. It should be understood that any suitable aromatization unit that increases the BTX and olefin content (e.g., increases the ethylene content) of the lower boiling isoparaffin stream 104 can be used as the aromatization unit 140. In one or more embodiments, the aromatization unit 140 can be a fixed bed reactor using a catalyst based on gallium ZSM-5 zeolite (Ga / ZSM-5). The fixed bed reactor can be operated under the following conditions: a temperature of 530°C to 570°C, such as 535°C to 565°C, 540°C to 560°C, 545°C to 555°C, or about 550°C, for 1.5h -1 Up to 2.5h -1 Weight hourly space velocity (WHSV), for example 1.8h -1 To 2.2h -1 or about 2.0h -1 , a pressure of 2 to 7 bars, such as 3 to 6 bars, 4 to 5 bars, or about 5 bars. The aromatized stream 106 exits the aromatization unit 140 and is introduced into the separation unit 160. The aromatized stream comprises 40 to 70 wt% aromatics, such as 45 to 70 wt% aromatics, 50 to 70 wt% aromatics, 55 to 70 wt% aromatics, 60 to 70 wt% aromatics, 65 to 70 wt% aromatics, 40 to 65 wt% aromatics, 45 to 65 wt% aromatics, 50 to 65 wt% aromatics, 55 to 65 wt% aromatics, 60 to 70 wt% aromatics, t% to 65wt% aromatics, 40wt% to 60wt% aromatics, 45wt% to 60wt% aromatics, 50wt% to 60wt% aromatics, 55wt% to 60wt% aromatics, 40wt% to 55wt% aromatics, 45wt% to 55wt% aromatics, 50wt% to 55wt% aromatics, 40wt% to 50wt% aromatics, 45wt% to 50wt% aromatics or 40wt% to 45wt% aromatics.

[0062] The higher boiling isoparaffin stream exits the splitting unit 130 and is introduced into the reforming unit 150. In the reforming unit 150, the isoparaffins, naphthalenes, and aromatics present in the higher boiling isoparaffin stream 105 are reformed to increase the BTX and olefin content, such as to increase the ethylene content. It should be understood that any suitable reforming unit that increases the BTX and olefin content (e.g., increases the ethylene content) of the higher boiling isoparaffin stream 105 can be used as the reforming unit 150. In one or more embodiments, the reforming unit 150 can be any conventional reforming unit, such as a UOP Platformer process operated at a temperature of 495° C. to 520° C., such as 500° C. to 515° C. or 505° C. to 510° C., a pressure of 4 bar to 45 bar, such as 10 bar to 35 bar, 15 bar to 30 bar, 20 bar to 25 bar, and 1 h -1 Until 5h -1 Liquid hourly space velocity (LHSV), for example 2h -1 Up to 4h -1 or about 3h -1 According to an embodiment, the reformed stream 107 comprising 55 wt% to 60 wt% BTX exits the reforming unit 150 and is introduced into the separation unit 160 .

[0063] The aromatized stream 106 and the reformed stream 107 are introduced into the separation unit 160. In the separation unit 160, the aromatized stream 106 and the reformed stream 107 are mixed and the normal paraffins are separated from the BTX and olefin products. The BTX and olefin products leave the separation unit 160 as a second BTX and olefin stream 109. Although Figure 1 109, it will be appreciated that the BTX and olefin stream 109 may be a plurality of different streams, such as streams of lower and higher boiling olefins, streams of lower and higher boiling aromatics, etc., in embodiments, depending on the separations performed in the separation unit 160. The separation unit 160 may be any conventional separator. The normal paraffins leave the separation unit 160 as a raffinate stream 111 and are recycled back to the steam cracking unit 120, where they may be converted to BTX and olefins.

[0064] In embodiments, the raffinate stream 111 comprises 80 wt% to 90 wt% C5 alkanes, e.g., 82 wt% to 90 wt% C5 alkanes, 85 wt% to 90 wt% C5 alkanes, 88 wt% to 90 wt% C5 alkanes, 80 wt% to 88 wt% C5 alkanes, 82 wt% to 88 wt% C5 alkanes, 85 wt% to 88 wt% C5 alkanes, 80 wt% to 85 wt% C5 alkanes, 82 wt% to 85 wt% C5 alkanes, or 80 wt% to 82 wt% C5 alkanes. In embodiments, the raffinate stream 111 comprises from 10 wt% to 20 wt% C6 alkanes, e.g., from 12 wt% to 20 wt% C6 alkanes, from 15 wt% to 20 wt% C6 alkanes, from 18 wt% to 20 wt% C6 alkanes, from 10 wt% to 18 wt% C6 alkanes, from 12 wt% to 18 wt% C6 alkanes, from 15 wt% to 18 wt% C6 alkanes, from 10 wt% to 15 wt% C6 alkanes, from 12 wt% to 15 wt% C6 alkanes, or from 10 wt% to 12 wt% C6 alkanes.

[0065] Example

[0066] Various embodiments of the methods and systems for processing naphtha will be further illustrated by the following examples. The examples are illustrative in nature and should not be construed as limiting the subject matter of the present disclosure.

[0067] Example 1: Comparison of normal paraffins and isoparaffins in steam cracking

[0068] In Example 1, two steam cracking simulations were performed using SPYRO 6 simulation software from Technip Energies. The first steam cracking simulation utilized a feed stream comprising n-butane, while the second steam cracking simulation utilized isobutane as the feed stream. The results provide a comparison of the yields of n-paraffins when used for steam cracking versus iso-paraffins when used for steam cracking.

[0069] Both the n-butane simulation and the isobutane simulation were performed using steam cracking at 840°C for a period of 0.4 seconds. The steam to oil ratio was set to 0.6. Table 1 below provides the chemical composition of the yield stream, where the yield is provided in weight percent. In Table 1, E+P+B olefins are the sum of ethylene (C2H4), propylene (C3H6) and butene (C4H8).

[0070] Table 1

[0071]

[0072]

[0073] As shown in Table 1, when n-butane is used, the yield of ethylene is 21.87 wt.% higher than that of isobutane, and when n-butane is used, the total olefin yield (E+P+B olefins) is 5.6 wt.% higher than that of isobutane. Therefore, when n-butane is used, the total olefin yield, especially the ethylene yield, for steam cracking is higher than that of isobutane.

[0074] Although the above examples utilize n-butane and isobutane, it would be expected that other n- and iso-alkanes would have similar effects, since n-butane and iso-butane have the greatest differences in steam cracking olefin yields. Thus, as carbon number decreases (from C4 for butane), the ethylene and propylene differences will become smaller. However, when carbon number increases to 7 (n-heptane and isoheptane), there is no significant difference in olefin yields.

[0075] Example 2: Adsorption of n-paraffins using zeolite 5A

[0076] In Example 2, the adsorption efficiency of zeolite 5A adsorbent for n-paraffins was tested by loading zeolite 5A into the adsorption zone and then introducing straight run naphtha from a refinery into the loaded adsorption zone. The operating conditions during the n-paraffin adsorption process were atmospheric pressure, 180°C, 0.025h -1 When the zeolite 5A adsorbent is saturated, n-pentene is used to regenerate the adsorbent. The regeneration operating conditions are atmospheric pressure, 180°C, 12h -1 Table 2 below provides the chemical composition of the isoparaffin stream leaving the adsorption zone during the adsorption process and the normal paraffin stream collected after regeneration.

[0077] Table 2

[0078] Normal paraffin Isoparaffin Naphthalene Aromatics Naphtha Stream 25.6 37.0 26.7 10.7 Isoparaffin stream 0.14 49.6 35.9 14.4 Normal paraffin stream 97.5 1.2 0.9 0.4

[0079] As shown in Table 2, zeolite 5A effectively adsorbs normal paraffins and separates them from isoparaffins.

[0080] Example 3: Comparison of Steam Cracking Using Naphtha, Isoparaffin Streams and Normal Paraffin Streams

[0081] In Example 3, a simulation was performed in a steam cracking unit using the stream provided by the adsorption in Example 2. Three steam cracking simulations were performed, using the naphtha stream from Example 2 in one simulation, the isoparaffin stream from Example 2 in one simulation, and the normal paraffin stream from Example 2 in one simulation. The steam cracking conditions were a temperature of 850° C., a pressure of 1.8 bar, a steam / hydrocarbon ratio of 0.5 kg / kg, and a residence time of 0.34 seconds. Table 3 below provides the weight specific yields of ethylene, propylene, and butene from each simulation.

[0082] Table 3

[0083] Ethylene Propylene Butene Total E+P+B Naphtha Stream 31.4 16.6 6.7 54.7 Isoparaffin stream 25.8 16.5 7.0 49.3 Normal paraffin stream 49.1 15.8 5.4 70.3

[0084] As shown in Table 3, the overall olefin yield of the normal paraffin stream is 15.6 wt.% higher than that of the naphtha stream, and the ethylene yield of the normal paraffin stream is 17.7 wt.% higher than that of the naphtha stream.

[0085] Example 4: Steam cracked normal paraffins and reformed isoparaffins with steam cracked naphtha or reformed naphtha Compare

[0086] In Example 4, three simulations were performed to compare the yield of steam cracked naphtha, the yield of reformed naphtha, and the yield of a combination of steam cracked normal paraffins and reformed iso-paraffins. In the first simulation, the naphtha stream provided in Example 2 was steam cracked using the parameters provided in Example 1. In the second simulation, the naphtha stream provided in Example 2 was reformed over a commercial Pt / Al2O3 catalyst at a temperature of 520°C, a pressure of 5 bar, and an LHSV of 1.5 h -1 In the third simulation, the normal paraffin stream provided in Example 2 was steam cracked using the parameters provided in Example 1, and the isoparaffin stream provided in Example 2 was reformed using the parameters in the second simulation. The weight specific yields of ethylene, propylene, butenes, and BTX are provided in Table 4 below.

[0087] Table 4

[0088]

[0089] In Table 4, E+P+B in Simulation 2 and E+P+B in isoparaffins to the reforming unit for Simulation 3 are calculated from the reforming products.

[0090] As shown in Table 4, the total chemical yield of Simulation 3 is 11 wt.% higher than when steam cracking naphtha, and more than 15 wt.% higher than when reforming naphtha.

[0091] The first aspect includes a method for forming olefins and aromatics from naphtha, comprising: introducing a naphtha feed stream into an adsorption unit, the adsorption unit comprising an adsorbent; adsorbing normal paraffins from the naphtha feed stream onto the adsorbent; removing an isoparaffin stream from the adsorption unit; introducing a desorbent stream into the adsorption unit, the desorbent stream comprising a desorbent; removing normal paraffins from the adsorbent with the desorbent, thereby forming a desorbed bottom sediment; collecting normal paraffins from the desorbed bottom sediment, thereby forming a normal paraffin stream; introducing the normal paraffin stream into a steam cracking unit; and forming olefins and aromatics from the normal paraffin stream in the steam cracking unit.

[0092] A second aspect includes the method of aspect 1, wherein the isoparaffin stream is introduced into a splitting unit, which splits the isoparaffin stream into a lower boiling point isoparaffin stream and a higher boiling point isoparaffin stream.

[0093] The third aspect includes the method of aspects 1 and 2, wherein a lower boiling point isoparaffin stream is introduced into an aromatization unit, where the lower boiling point isoparaffin stream is aromatized into an aromatized stream, and a higher boiling point isoparaffin stream is introduced into a reforming unit, where the higher boiling point isoparaffin stream is reformed into a reformed stream.

[0094] A fourth aspect includes the method of aspects 1 to 3, wherein the aromatization stream and the reforming stream are introduced into a separation unit.

[0095] A fifth aspect includes the method of aspects 1 to 4, wherein the aromatization stream and the reforming stream are mixed together in a separation unit and separated into a BTX and olefin stream and a raffinate stream, wherein the raffinate stream comprises normal paraffins.

[0096] A sixth aspect includes the method of aspects 1 to 5, wherein the raffinate stream is recycled back to the steam cracking unit.

[0097] A seventh aspect includes the method of aspects 1 to 6, wherein the adsorbent is selected from the group consisting of zeolite 5A, zeolite T, chabazite, and erionite.

[0098] An eighth aspect includes the method of aspects 1 to 7, wherein the adsorbent is dried in air or nitrogen at a temperature of 350° C. to 550° C. for a duration of 2 hours to 12 hours prior to adsorbing normal paraffins from the naphtha feed stream onto the adsorbent.

[0099] The ninth aspect includes the method of aspects 1 to 8, wherein the -1 Until 10h -1 The normal paraffins are adsorbed from the naphtha feed stream onto the adsorbent at a liquid space velocity of 1000 Å.

[0100] The tenth aspect includes the method of aspects 1 to 9, wherein the desorbent is selected from n-pentane or hexane.

[0101] The eleventh aspect includes the method of aspects 1 to 10, wherein the -1 To 20.0h -1 The normal paraffins are removed from the adsorbent using a desorbent stream at a liquid space velocity of 1000 Å.

[0102] A twelfth aspect includes the method of aspects 1 to 11, wherein the normal paraffin stream comprises at least 95.0 wt.% normal paraffins.

[0103] A thirteenth aspect includes the method of aspects 1 to 12, wherein the isoparaffin stream comprises at least 95.0 wt.% isoparaffins.

[0104] The fourteenth aspect includes the method described in aspects 1 to 13, wherein the adsorption unit includes a first adsorption zone and a second adsorption zone, each of the first adsorption zone and the second adsorption zone contains an adsorbent, a first naphtha feed stream is introduced into the first adsorption zone, and a second desorbent stream is introduced into the second adsorption zone at the same time, and the first desorbent stream is introduced into the first adsorption zone, and the second naphtha feed stream is introduced into the second adsorption zone at the same time, and the first naphtha feed stream and the first desorbent stream are not introduced into the first adsorption zone at the same time, and the second naphtha feed stream and the second desorbent stream are not introduced into the second adsorption zone at the same time.

[0105] A fifteenth aspect includes a system for forming olefins and aromatics from naphtha, the system comprising: an adsorption unit located upstream of a splitting unit and a steam cracking unit and connected to the splitting unit and steam cracking unit fluids; the steam cracking unit is located downstream of the adsorption unit and connected to the adsorption unit fluids, and the steam cracking unit is located upstream of a separation unit and connected to the separation unit fluids; the splitting unit is located downstream of the adsorption unit and connected to the adsorption unit fluids, and the splitting unit is located upstream of an aromatization unit and connected to the aromatization unit and reforming unit fluids; the aromatization unit is located downstream of the splitting unit and connected to the splitting unit fluids, and the aromatization unit is located upstream of the separation unit and connected to the separation unit fluids; the reforming unit is located downstream of the splitting unit and connected to the splitting unit fluids, and the reforming unit is located upstream of the separation unit and connected to the separation unit fluids; the separation unit is located downstream of the aromatization unit and connected to the aromatization unit and reforming unit fluids, and the separation unit is located downstream of the steam cracking unit and connected to the steam cracking unit fluids, wherein the adsorption unit comprises an adsorbent selected from the group consisting of zeolite 5A, zeolite T, chabazite, and erionite.

[0106] A sixteenth aspect includes the system of aspect 15, wherein the adsorbent is zeolite 5A.

[0107] A seventeenth aspect includes the system of aspects 15 and 16, wherein the adsorption unit is configured to adsorb normal paraffins and allow iso-paraffins to pass through the adsorption unit.

[0108] An eighteenth aspect includes the system of aspects 15 to 17, wherein the adsorption unit is configured such that the iso-paraffins exiting the adsorption unit are introduced into the splitting unit, and such that the normal-paraffins exiting the adsorption unit are introduced into the steam cracking unit.

[0109] A nineteenth aspect includes the system of aspects 15 to 18, wherein the adsorption unit comprises a first adsorption zone and a second adsorption zone, each of the first adsorption zone and the second adsorption zone comprising an adsorbent.

[0110] The twentieth aspect includes the system described in aspects 15 to 19, wherein the first adsorption zone and the second adsorption zone are configured such that: the first naphtha feed stream is introduced into the first adsorption zone, and the second desorbent stream is introduced into the second adsorption zone at the same time; the first desorbent stream is introduced into the first adsorption zone, and the second naphtha feed stream is introduced into the second adsorption zone at the same time; the first naphtha feed stream and the first desorbent stream are not introduced into the first adsorption zone at the same time; and the second naphtha feed stream and the second desorbent stream are not introduced into the second adsorption zone at the same time.

[0111] It should be noted that one or more of the following claims utilize the term "wherein" as a transition phrase. For purposes of defining the present technology, it should be noted that this term is introduced in the claims as an open transition phrase used to introduce a recitation of a series of features of a structure and should be interpreted in a manner similar to the more commonly used open-ended preamble term "comprising."

[0112] It should be understood that any two quantitative values ​​assigned to a property may form a range for that property, and that all combinations of ranges formed by all of the stated quantitative values ​​for a given property are contemplated in the present disclosure.

[0113] Having described the subject matter of the present disclosure in detail and with reference to specific embodiments, it should be noted that the various details described in the present disclosure should not be viewed as implying that these details relate to elements of the essential parts of the various embodiments described in the present disclosure, even if the specific elements are shown in each of the drawings accompanying the present specification. On the contrary, the claims appended hereto should be viewed as the only indication of the breadth of the present disclosure and the corresponding scope of the various embodiments described in the present disclosure. Moreover, it is apparent that modifications and variations are possible without departing from the scope of the appended claims.

Claims

1. A method for forming olefins and aromatics from naphtha, comprising: introducing a naphtha feed stream into an adsorption unit, the adsorption unit comprising an adsorbent; adsorbing normal paraffins from the naphtha feed stream onto the adsorbent; removing an isoparaffin stream from said adsorption unit; introducing a desorbent stream into the adsorption unit, the desorbent stream comprising a desorbent; removing the normal paraffins from the adsorbent with the desorbent, thereby forming a desorbed bottoms sediment; collecting the normal paraffins from the desorbed bottoms to form a normal paraffin stream; introducing the normal paraffin stream into a steam cracking unit; as well as Olefins and aromatics are formed from the n-paraffin stream in the steam cracking unit.

2. The process according to claim 1, wherein the isoparaffin stream is introduced into a splitting unit which splits the isoparaffin stream into a lower boiling isoparaffin stream and a higher boiling isoparaffin stream.

3. The process of claim 2, wherein the lower boiling isoparaffin stream is introduced into an aromatization unit, wherein the lower boiling isoparaffin stream is aromatized into an aromatized stream in the aromatization unit, and The higher boiling isoparaffin stream is introduced into a reforming unit where it is reformed into a reformed stream.

4. The process according to claim 3, wherein the aromatized stream and the reformed stream are introduced into a separation unit.

5. The process of claim 4, wherein the aromatization stream and the reforming stream are mixed together in the separation unit and separated into a BTX and olefin stream and a raffinate stream, wherein the raffinate stream comprises normal paraffins.

6. The process of claim 5, wherein the raffinate stream is recycled back to the steam cracking unit.

7. The method of claim 1, wherein the adsorbent is selected from the group consisting of zeolite 5A, zeolite T, chabazite, and erionite.

8. The process of claim 1, wherein the adsorbent is dried in air or nitrogen at a temperature of 350°C to 550°C for a duration of 2 hours to 12 hours prior to adsorbing normal paraffins from the naphtha feed stream onto the adsorbent.

9. The method according to claim 1, wherein the temperature is 100°C to 300°C for 0.001h -1 Until 10h -1 The normal paraffins are adsorbed from the naphtha feed stream onto the adsorbent at a liquid space velocity of 100 Å.

10. The method according to claim 1, wherein the desorbent is selected from n-pentane or hexane.

11. The method according to claim 1, wherein the temperature is between 100°C and 300°C for 10.0 hours. -1 To 20.0h -1 The n-paraffins are removed from the adsorbent using the desorbent stream at a liquid space velocity of 100 Å.

12. The process of claim 1, wherein the normal paraffin stream comprises at least 95.0 wt.% normal paraffins.

13. The process of claim 1, wherein the isoparaffin stream comprises at least 95.0 wt.% isoparaffins.

14. The method according to claim 1, wherein the adsorption unit comprises a first adsorption zone and a second adsorption zone, each of the first adsorption zone and the second adsorption zone comprising the adsorbent, A first naphtha feed stream is introduced into the first adsorption zone while a second desorbent stream is introduced into the second adsorption zone, and a first desorbent stream is introduced into the first adsorption zone while a second naphtha feed stream is introduced into the second adsorption zone, and the first naphtha feed stream and the first desorbent stream are not introduced into the first adsorption zone at the same time, and the second naphtha feed stream and the second desorbent stream are not introduced into the second adsorption zone at the same time.

15. A system for forming olefins and aromatics from naphtha, the system comprising: an adsorption unit located upstream of and in fluid connection with the splitting unit and the steam cracking unit; The steam cracking unit is located downstream of the adsorption unit and is fluidly connected to the adsorption unit, and the steam cracking unit is located upstream of the separation unit and is fluidly connected to the separation unit; The splitting unit is located downstream of and fluidly connected to the adsorption unit, and the splitting unit is located upstream of and fluidly connected to an aromatization unit and a reforming unit; The aromatization unit is located downstream of the splitting unit and is fluidly connected to the splitting unit, and the aromatization unit is located upstream of the separation unit and is fluidly connected to the separation unit; The reforming unit is located downstream of the splitting unit and is fluidly connected to the splitting unit, and the reforming unit is located upstream of the separation unit and is fluidly connected to the separation unit; The separation unit is located downstream of and fluidly connected to the aromatization unit and the reforming unit, and the separation unit is located downstream of and fluidly connected to the steam cracking unit, wherein the adsorption unit comprises an adsorbent selected from the group consisting of zeolite 5A, zeolite T, chabazite, and erionite.

16. The system of claim 15, wherein the adsorbent is zeolite 5A.

17. The system of claim 15, wherein the adsorption unit is configured to adsorb normal paraffins and allow iso-paraffins to pass through the adsorption unit.

18. The system of claim 17, wherein the adsorption unit is configured such that iso-paraffins exiting the adsorption unit are introduced into the splitting unit and such that normal-paraffins exiting the adsorption unit are introduced into the steam cracking unit.

19. The system of claim 15, wherein the adsorption unit comprises a first adsorption zone and a second adsorption zone, each of the first adsorption zone and the second adsorption zone containing the adsorbent.

20. The system of claim 19, wherein the first adsorption zone and the second adsorption zone are configured such that: A first naphtha feed stream is introduced into the first adsorption zone while a second desorbent stream is introduced into the second adsorption zone; A first desorbent stream is introduced into the first adsorption zone while a second naphtha feed stream is introduced into the second adsorption zone; the first naphtha feed stream and the first desorbent stream are not introduced into the first adsorption zone simultaneously; and The second naphtha feed stream and the second desorbent stream are not introduced into the second adsorption zone simultaneously.

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