Process for converting whole crude oil to ethylene

Abstract

A process for converting whole crude oil and other heavy hydrocarbon streams to produce ethylene is provided. The process includes feeding a hydrotreated mid-boiling fraction, a hydrotreated resid fraction, or both, and a light boiling fraction to a steam cracker and recovering a light fraction. The light fraction is fed to a first separator and a C1-C3 stream and a mixed C4 and C4 + stream comprising isoolefins, olefins and dienes are recovered, and the mixed C4 and C4 + stream is fed to a second separator and a mixed C4 stream comprising isoolefins, olefins and C4 + streams is recovered. A portion of the mixed C4 stream is dimerized in a dimerization unit to produce a dimerization product stream, hydrogenated in a total hydrogenation system to produce a hydrogenated dimerization product stream, and cracked in a thermal cracking reactor system to produce one or more of hydrogen, methane, ethylene, propylene, n-butene, and isobutene.

Description

TECHNICAL FIELD

[0001] Embodiments herein relate to processes and systems for producing ethylene from crude oil and low value heavy hydrocarbon streams. BACKGROUND

[0002] If high boiling point compounds in crude oil are sent to a steam cracker, they can cause significant operational problems. High boiling point compounds are prone to coke formation, largely due to their high asphaltenes content. Therefore, high boiling point compounds are typically removed before sending the lighter fractions to different petrochemical plants, such as steam crackers or aromatics complexes. However, the removal process increases the capital cost of the overall process and reduces profitability, as the removed high boiling point compounds can only be sold as low value fuel oil. Further, conversion of vacuum residue without substantial formation of HPNA (heavy polynuclear aromatics) which are detrimental to the steam cracking furnace downstream of the process has been a challenge so far.

[0003] USP 3,617,493 describes a process in which crude oil is sent to the convection section of a steam cracker and then to a separation zone, where a portion of the feed boiling below about 450°F is separated from the rest of the feed, and then sent into the high temperature section of the steam cracker with steam and subjected to cracking conditions.

[0004] USP 4,133,777 teaches a process in which a feed oil is first flowed downward in drop form through a fixed bed of HDM catalyst and then downward through a fixed bed of a promoted catalyst containing selected Group VI and Group VIII metals, with little hydrocracking occurring in the combined process.

[0005] USP 5603824 discloses a process for upgrading a waxy hydrocarbon feed mixture containing sulfur compounds boiling in the distillate range to reduce sulfur content and 85% point while maintaining high octane value of naphtha by-product and maximizing distillate yield. The process employs a single downflow reactor with at least two catalyst beds and interbed redistributors between the beds. The top bed contains a hydrocracking catalyst, preferably zeolite beta, and the bottom bed contains a dewaxing catalyst, preferably ZSM-5.

[0006] USP 3,730,879 discloses a two-bed catalytic process for hydrodesulfurization of crude oil or reduced distillate fraction, wherein at least 50% of the total pore volume of the first bed catalyst consists of pores having diameters in the range of 100 to 200 Angstroms.

[0007] USP 3,830,720 discloses a two-bed catalytic process for hydrocracking and hydrodesulfurization of residual oil, wherein a small pore catalyst is disposed upstream of a large pore catalyst.

[0008] USP 3,876,523 describes a new type of catalyst and a process for catalytically demetallizing and desulfurizing hydrocarbon oils including residual oil fractions. The process described therein uses a catalyst including a hydrogenation component such as cobalt and molybdenum oxides complexed on alumina. While this catalyst is very effective for demetallization of residual oil fractions and has good stability over time, its effectiveness is dramatically improved when it is used in combination with a second catalyst having different key characteristics in a particular manner. The catalyst of the type described in US Patent No. 3,876,523 will be referred to as a first catalyst, it being understood that this first catalyst is upstream of a second catalyst having different characteristics.

[0009] USP 4,153,539 discloses improved hydrogen utilization and / or higher conversion of desired products in hydrofining or hydrocracking processes when using dual earthenware particles for hydrofining, catalytic reforming, fixed bed alkylation processes, etc. of light hydrocarbon fractions.

[0010] USP 4,016,067 discloses that hydrocarbon oils, preferably residual oil fractions, are catalytically hydrotreated to very effectively remove metals and sulfur and to very slowly age the catalyst system by sequentially contacting the oil with two different catalysts. The first catalyst, which is upstream of the second catalyst, is characterized by at least 60% of its pore volume being pores having a diameter greater than 100 Angstroms, and other characteristics specified below. The second catalyst, which is downstream relative to the first catalyst, is characterized by a substantial portion of its pore volume being pores having a diameter less than 100 Angstroms.

[0011] The dual catalyst unit of USP 4,016,067 is used to demetallize and / or desulfurize any hydrocarbon oil having a metal and / or sulfur content that is too high for a particular application. The dual catalyst unit is particularly effective for producing a low metal and / or low sulfur content feedstock for catalytic cracking or coking. In the process of removing metals and sulfur, the hydrocarbon oil is also simultaneously enriched in hydrogen, making it a more suitable feedstock for these processes.

[0012] In general, these and prior art total crude oil conversion processes typically convert less than 50% of the crude oil into more desirable end products, including petrochemical products such as ethylene, propylene, butylenes, pentenes, and light aromatics, for example. In general, 20% of the total crude oil is pre-removed in the process, removing the most heavy components that are difficult to convert. Approximately another 20% of the total crude oil is typically converted to pyrolysis oil, and approximately 10% is over-converted to methane. In some industries, it can be desirable to further upgrade the end products.

[0013] For example, to meet fuel blend requirements, such as octane or vapor pressure requirements, smaller olefin molecules, such as C1-C4, can be upgraded to produce longer chain molecules. Alternatively, smaller olefin molecules can be etherified in order to increase the oxygen content of the molecules and the resulting fuel blend. Etherification side reactions can also act as a moderator reaction to control the main reactor, selectively forming dimers instead of trimers.

[0014] One commonly used method of upgrading smaller olefin molecules, such as C2 to C5 olefins, is dimerization. Blending C4, isobutylene, isoamylene (such as 2-methyl-1-butene and 2-methyl-2-butene), and pentenes (such as 1-pentene and 2-pentene) is commercially significant in many applications.

[0015] Dimerization reactions involve contacting an olefin with a catalyst to produce long chain molecules. Dimers can be composed of two or more component olefin molecules. For example, dimerization is a type of oligomerization reaction, limited to the combination of two olefin molecules. If the olefin feed contains only one type of olefin, dimerization products are formed. If the olefin feed contains two or more different olefins or olefin isomers, co-dimerization products can also be formed.

[0016] Specifically, isobutylene olefin dimerization is widely used to produce isooctylene, which is an intermediate that can be hydrogenated to produce isooctane, a high value gasoline blend additive. Several representative olefin dimerization reactions are shown below:

[0017] U.S. Patent Nos. 3,960,978 and 4,021,502 disclose a gas phase olefin dimerization process in which C2to C5olefins fed as pure olefins or in a mixture with paraffins are reacted to dimerize by contact with a fixed bed of zeolite catalyst. Other dimerization processes are disclosed in, for example, U.S. Patent Nos. 4,242,530; 4,375,576; 5,003,124; 7,145,049; 6,335,473; 6,774,275; 6,858,770; 6,936,742; 6,995,296; 7,250,542; 7,288,693; 7,319,180; 6,689,927; 6,376,731; 5,877,372; 4,331,824; 4,100,220; and U.S. Patent Application Publication Nos. 20080064911; 20080045763; 20070161843; 20060030741; 20040210093; and 20040006252, among others. Acidic resin catalysts have also been found useful in various other petrochemical processes, including formation of ethers, hydration of olefins, esterification, and epoxidation, such as described in U.S. Patent Nos. 4,551,567 and 4,629,710.

[0018] Processes for olefin dimerization on such resin catalysts require periodic shutdown of the dimerization unit to replace and / or regenerate the catalyst. In addition, such solid catalytic processes can require additives ("selective activators") to improve the selectivity of the catalyst to dimers, where the additives can cause undesirable acid precipitation, deactivating the catalyst, and can additionally require complex separation processes to remove the additives from the resulting product stream. SUMMARY

[0019] In an aspect, embodiments disclosed herein relate to a process for converting whole crude oil and other heavy hydrocarbons streams to produce ethylene. The process includes separating whole crude oil into at least a light boiling point fraction, a medium boiling point fraction, and a high boiling point residue fraction; treating the medium boiling point fraction, the high boiling point fraction, or both in one or more hydrotreating steps to produce a hydrotreated medium boiling point fraction, a hydrotreated residue fraction, or both; feeding the hydrotreated medium boiling point fraction, the hydrotreated residue fraction, or both, and the light boiling point fraction to a steam cracker; recovering a light ends fraction including C1-C4 hydrocarbons and pyrolysis oil; feeding the light ends fraction to a first separator and recovering a C1-C3 stream and a mixed C4 and C4+ stream including isoolefins, olefins, and dienes; feeding the mixed C4 and C4+ stream including isoolefins, olefins, and dienes to a second separator and recovering a mixed C4 stream including isoolefins, olefins, and C4+ stream; dimerizing the mixed C4 stream in a dimerization unit to produce a dimerization product stream; hydrogenating the dimerization product stream in a total hydrogenation system to produce a hydrogenated dimerization product stream; and cracking the hydrogenated dimerization product stream in a thermal cracking reactor system including one or more thermal cracking reactors to produce one or more of hydrogen, methane, ethylene, propylene, n-butenes, and iso-butenes.

[0020] Other aspects and advantages will be apparent from the following description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a simplified process flow diagram of a system for converting whole crude oil and heavy hydrocarbons to produce ethylene according to embodiments herein.

[0022] Figure 2 is a general simplified process flow diagram of a system for converting whole crude oil and heavy hydrocarbons to produce high value products according to embodiments herein.

[0023] Figure 3 is a simplified process flow diagram of a process for converting whole crude oil and heavy hydrocarbons to produce ethylene according to embodiments herein. DETAILED DESCRIPTION

[0024] As used herein, the term “petrochemicals” refers to hydrocarbons including light olefins and diolefins and C6-C8aromatics. Thus, petrochemicals refer to hydrocarbons including ethylene, propylene, butene, butadiene, pentene, pentadiene, and benzene, toluene, and xylene. As to a subset of petrochemicals, the term “chemicals” as used herein refers to ethylene, propylene, butadiene, 1-butene, iso-butene, benzene, toluene, and p-xylene.

[0025] Hydrofinishing is a catalytic process, usually conducted in the presence of free hydrogen, in which the primary purpose in processing a hydrocarbon feedstock is to remove various metal contaminants (e.g., arsenic), heteroatoms (e.g., sulfur, nitrogen, and oxygen), and aromatics from the feedstock. Generally, in hydrofinishing operations, cleavage of hydrocarbon molecules (i.e., breaking larger hydrocarbon molecules into smaller hydrocarbon molecules) is minimized. As used herein, the term "hydrofinishing" refers to a refining process in which a feed stream is reacted with hydrogen in the presence of a catalyst to remove impurities such as sulfur, nitrogen, oxygen, and / or metals (e.g., nickel or vanadium) from the feed stream (e.g., atmospheric tower bottoms) by a reduction process. The hydrofinishing process can vary greatly depending on the type of feed to the hydrofinishing unit. For example, light feeds (e.g., naphtha) contain very little and few types of impurities, whereas heavy feeds (e.g., ATB) typically contain many different heavy compounds present in crude oil. In addition to containing heavy compounds, the impurities in heavy feeds are more complex and more difficult to treat than the impurities present in light feeds. Thus, hydrofinishing of light feeds is typically conducted at lower reaction severity, whereas heavy feeds require higher reaction pressures and temperatures.

[0026] Hydrocracking refers to a process in which hydrogenation and dehydrogenation are accompanied by hydrocarbon cracking / fragmentation, such as converting heavier hydrocarbons to lighter hydrocarbons, or converting aromatics and / or naphthenes (naphthenic hydrocarbons) to acyclic branched alkanes.

[0027] As used herein, "conditioning" and like terms refer to the conversion of hydrocarbons by one or both of hydrocracking and hydrofinishing. "Destructive hydrogenation" and like terms refer to the cleavage of hydrocarbon molecular bonds of a hydrocarbon and the associated hydrogen saturation of the remaining hydrocarbon fragments, which can produce stable, lower boiling hydrocarbon oil products, and can include both hydrocracking and hydrofinishing.

[0028] As used herein, "dimerization" refers to a chemical reaction in which smaller olefin molecules, such as C2to C5olefins, are upgraded to longer chain hydrocarbons. For example, isobutylene is of commercial interest in many applications and can be used as a feed to a dimerization reaction. For example, isobutylene is one of the co-monomers in butyl rubber. Isobutylene can also be dimerized to produce compounds that can be used as chemical feedstocks for further reactions or gasoline blending. Diisobutylene, the dimer of isobutylene, has particular commercial value in a variety of applications. For example, diisobutylene can be used as an alkylating reaction feedstock or as an intermediate in the production of detergents. Diisobutylene can also be hydrogenated to pure isooctane (2,2,4-trimethylpentane), which is highly preferred in gasoline blending.

[0029] Dimerization reactions involve contacting an olefin with a catalyst to produce longer chain molecules. Dimers can be composed of two olefin molecules, while trimers can be composed of three olefin molecules. For example, dimerization is a type of reaction that is limited primarily to the combination of only two olefin molecules, producing dimerization products with a small amount of trimers and longer chain molecules.

[0030] Specifically, C4 olefin dimerization is widely used to produce isooctene, which is an intermediate that can be hydrogenated to produce isooctane, a high value gasoline blending additive. The following shows a non-limiting example or representative olefin dimerization reaction:

[0031]

[0032] Hydrogenation as used herein involves a catalytic chemical reaction that adds hydrogen to unsaturated hydrocarbons. One particular application of hydrogenation is the saturation of olefins and diolefins to produce alkanes. As catalysts, metals such as platinum, palladium, nickel, and the like can be cited. Hydrogenation reactions can be carried out at low temperatures to avoid cracking or other side reactions.

[0033] Integration of fractionation, hydrotreating, steam cracking, dimerization, hydrogenation, and hydrocracking can result in an efficient facility, and in some embodiments can convert greater than 55%, greater than 60%, greater than 65%, greater than 70%, greater than 75%, greater than 80%, or greater than 85% of whole crude oil to valuable petrochemicals, such as ethylene. In other embodiments, integration of fractionation, hydrotreating, steam cracking, dimerization, hydrogenation, and hydrocracking can result in an efficient facility, and in some embodiments can convert greater than 55%, greater than 60%, greater than 65%, greater than 70%, greater than 75%, greater than 80%, or greater than 85% of whole crude oil to small chain hydrocarbons. Thus, embodiments herein can provide systems and methods for conditioning a feed, even including the heaviest, least desirable residual components, into components that can be vaporized and passed to the radiant section of a steam cracker, resulting in significant improvements over existing processes with respect to low petrochemical conversion and reduced steam cracker fouling.

[0034] Embodiments herein relate to processes and systems that can employ crude oil and / or low value heavy hydrocarbons as feed and produce valuable petrochemical products including ethylene. More specifically, embodiments herein relate to processes and systems for producing olefins by thermal cracking of pre-conditioned crude oil or condensate and using the olefins as feed to produce ethylene by dimerization, hydrogenation, and hydrocracking. In one or more embodiments of the processes disclosed herein, the residual fraction of whole crude and condensate can be conditioned to produce additional feedstock that can be used as a steam cracker feedstock. In another embodiment of the processes disclosed herein, the streams produced by the steam cracker can be further processed and produce chemical streams including isoolefins. In other embodiments of the processes disclosed herein, the isoolefins can be dimerized and hydrogenated to produce ethylene as the final product.

[0035] The hydrocarbon mixtures that can be used in the embodiments disclosed herein can include various hydrocarbon mixtures having a boiling range, where the final boiling point of the mixture can be greater than 500°C, such as greater than 525°C, 550°C, or 575°C. The amount of high boiling point hydrocarbons, such as hydrocarbons with boiling points in excess of 550°C, can be as low as 0.1 wt%, 1 wt%, or 2 wt%, but can be as high as 10 wt%, 25 wt%, 50 wt%, or greater. This description is illustrated for crude oil, such as whole crude, but any hydrocarbon mixture with a high boiling end point can be used. However, the processes disclosed herein can be applied to crude oil, condensate, and hydrocarbons with a wide boiling range curve and an end point above 500°C. Such hydrocarbon mixtures can include whole crude, virgin crude, hydrotreated crude, gas oil, vacuum gas oil, heating oil, jet fuel, diesel, kerosene, gasoline, synthetic naphtha, raffinate reformate, Fischer-Tropsch liquids, Fischer-Tropsch gases, natural gas, gasoline, distillate oil, virgin naphtha, natural gas condensate, atmospheric pipeline distillation column bottoms, vacuum pipeline distillation streams including column bottoms, naphtha to gas oil condensate with a wide boiling point range, heavy non- virgin hydrocarbon streams from refineries, vacuum gas oil, heavy gas oil, atmospheric residue, hydrocracker wax, and Fischer-Tropsch wax, among others. In some embodiments, the hydrocarbon mixtures can include hydrocarbons boiling from the naphtha range or lighter to the vacuum gas oil range or heavier.

[0036] When the final boiling point of the hydrocarbon mixture is very high, such as over 550°C, the hydrocarbon mixture cannot be directly processed in a steam pyrolysis reactor to produce olefins. The presence of these heavy hydrocarbons results in the formation of coke in the reactor, where coking can occur in one or more of the convection section preheat coils or the superheat coils, in the radiant coils, or in the transfer line exchangers, and this coking can occur very quickly, such as within a few hours. Whole crude oil is not typically processed commercially for cracking because it is not economical. Whole crude oil is typically fractionated, and only specific fractions are used in a steam cracker heater to produce olefins. The remainder is used in other processes. The cracking reaction proceeds via a free radical mechanism. Thus, high ethylene yields can be obtained when cracking at high temperatures. Lighter feeds, such as butane and pentane, require high reactor temperatures to obtain high olefin yields. Heavy feeds, such as gas oil and vacuum gas oil (VGO), require lower temperatures. Crude oil contains a distribution of compounds from butane to VGO and residue (materials with boiling points over 550°C). Placing whole crude oil at high temperatures without separation results in high yields of coke (a byproduct of high intensity cracking hydrocarbons) and plugging of the steam pyrolysis reactor. The steam pyrolysis reactor must be shut down periodically and cleaned of coke by steam / air decoking. The time between two cleaning periods when producing olefins is called the run length. When whole crude oil is cracked without separation, coke deposits in the convection section coils (evaporating fluids), the radiant section (where the olefin production reactions occur), and / or the transfer line exchangers (where the reactions are quickly stopped by cooling to preserve olefin yields).

[0037] According to embodiments herein, a process and system for producing a feed stream for a steam cracker from whole crude oil can include a feed preparation section, a crude oil conditioning section, an optional aromatics complex, and a steam cracker. For example, the feed preparation section can include a desalter. The desalted crude oil is then conditioned and processed so that a crackable feed is sent to the steam cracker and / or the aromatics complex. The conditioning section can allow an operator to maximize chemical production while maintaining a reasonable decoking frequency of the furnace. Another goal of the crude oil conditioning unit is to ensure complete or substantially complete (95+) conversion of asphaltenes to low boiling point components, thereby increasing chemical production while reducing the formation of heavy polynuclear aromatics (HPNA).

[0038] Accordingly, the process according to embodiments herein can convert the heavier fractions of the crude oil into high value petrochemical products and can minimize the amount of hydrocarbons sent to a fuel oil pool, which significantly improves profitability. The small fuel oil pool produced can also be upgraded to low sulfur fuel oil that meets the IMO 2020 standards, further increasing product value.

[0039] As mentioned above, high boiling compounds in crude oil can cause severe operational problems if sent to a steam cracker, as they tend to form coke, primarily due to their high asphaltenes content. Therefore, high boiling compounds are typically removed before sending the lighter fractions to different petrochemical units, such as steam crackers and aromatics complexes. The removal process increases the capital cost of the overall process and reduces profitability, as the removed high boiling compounds can only be sold as low value fuel oil. Further, converting vacuum residue without forming significant amounts of HPNA, which are detrimental to the steam cracking furnace downstream of the process, has been a challenge in the industry to date. The process and system according to the embodiments described herein can overcome these challenges.

[0040] The configuration of the system and process for converting whole crude oil and heavy hydrocarbons according to the embodiments described herein can efficiently process residue conversion while maximizing petrochemical product conversion and maintaining a lower coking tendency in the steam cracker. This is achieved by adding one or more integrated separation devices (ISD), solvent deasphalting units, and / or catalytic cracking units to the crude oil conditioning process.

[0041] The upgraded crude oil stream from the crude oil conditioning unit, such as from a fixed bed crude oil conditioning unit and hydrocracker, is a suitable feedstock for the steam cracker as well as the aromatics complex (when present). This can result in a decrease in the overall process yield of low value fuel oil and an increase in the yield of high value olefins.

[0042] The separation of various fractions, such as low boiling fraction (e.g., 160°C- fraction), medium boiling fraction (e.g., 160°C to 490°C fraction), and high boiling fraction (e.g., 490°C+ fraction), can improve the capital efficiency and operating cost of the process and system disclosed herein. Although three fractions are mentioned in many embodiments herein, the inventors recognize that condensate oil, which typically has a small amount of high boiling components, and whole crude oil, which has a large amount of high boiling components, can be treated differently. Therefore, a wide boiling range petroleum feed can be separated into one, two, three, or more individual fractions, and each fraction can be treated separately under optimal conditions.

[0043] The whole crude oil can be separated into the desired fractions using one or more separators (distillation columns, flash tanks, etc.). In some embodiments, the separation of the petroleum feed can be performed in an integrated separation device (ISD), such as disclosed in US20130197283, which is incorporated herein by reference. In the ISD, an initial separation of the low boiling fraction is performed based on a combination of centrifugal and cyclonic effects to separate the desired vapor fraction from the liquid. Additional separation steps can then be used to separate the medium boiling fraction from the high boiling components.

[0044] Generally, hydrocarbon components having a boiling point greater than 490°C contain asphaltenes and Conradson carbon residue and thus require appropriate treatment, as further described below. While embodiments are described as including a low fraction of less than about 90°C to 250°C (such as a 160°C- fraction) and a heavy fraction of greater than about 400°C to 560°C (such as a 490°C+ fraction), it is noted that the actual fraction points can vary depending on the type of whole crude oil or other heavy fraction being treated. For example, for a crude oil containing low metal or nitrogen content, or a large amount of "easy to process" components, for example, boiling at temperatures up to 525°C, 540°C, or 565°C, it is possible to raise the mid / high fraction point while still achieving the benefits of the embodiments herein. Similarly, in some embodiments, the low / mid fraction point can be as high as 220°C, or in other embodiments, as high as 250°C. Further, a low / mid fraction point of about 160°C has been found to provide benefits for the sizing and operation of reactors, such as fixed bed conditioning reactors for conditioning mid- distillate hydrocarbons (mid-distillate). Further, for certain feeds, such as condensate, the low / mid fraction point can be as high as 565°C. The ability to vary the fraction points can increase the flexibility of the processing scheme according to the embodiments herein, allowing for the processing of a variety of feeds while still producing a desired product mixture.

[0045] Thus, in some embodiments, the light fraction can include hydrocarbons having a boiling point of up to about 90°C (e.g., a 90°C- fraction), up to about 100°C, up to about 110°C, up to about 120°C, up to about 130°C, up to about 140°C, up to about 150°C, up to about 160°C, up to about 170°C, up to about 180°C, up to about 190°C, up to about 200°C, up to about 210°C, up to about 220°C, up to about 230°C, up to about 240°C, up to about 250°C (e.g., a 250°C- fraction), up to about 300°C, up to about 350°C, up to about 400°C, up to about 500°C, or up to about 565°C. Embodiments herein also contemplate that the light fraction is a hydrocarbon having a boiling point of up to an intermediate temperature in the above ranges.

[0046] Depending on the fractionation mechanism used, the light hydrocarbon "fractions" can be relatively clean, meaning that the light fraction can not have any significant amount (as used herein > 1 wt%) of compounds with boiling points higher than the intended boiling point temperature target. For example, a 160°C- fraction can not have any significant amount of hydrocarbon compounds boiling higher than 160°C (i.e., > 1 wt%). In other embodiments, the intended target "fraction" temperature described above can be the 95% boiling point temperature, or in other embodiments the 85% boiling point temperature, such as can be measured using ASTM D86 or ASTM D2887, or measured from true boiling point (TBP) analysis according to, for example, ASTM D2892 and ASTM D7169 for heavy streams, such as those streams boiling higher than about 400°C. In such embodiments, there can be up to 5 wt% or up to 15 wt% of compounds higher than the indicated "fraction" point temperature. For many whole crudes, the low / medium fraction point can be such that the light boiling fraction has a 95% boiling point temperature in the range of about 90°C to about 250°C. However, for other feeds, such as condensate, the light boiling fraction can have a 95% boiling point temperature in the range of, for example, about 500°C to about 565°C.

[0047] In some embodiments, the intermediate fraction can include hydrocarbons having a boiling point from a lower limit of the upper limit temperature of the light fraction (e.g., 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 300°C, 350°C, or 400°C) to an upper limit of hydrocarbons having a boiling point of up to about 350°C, up to about 375°C, up to about 400°C, up to about 410°C, up to about 420°C, up to about 430°C, up to about 440°C, up to about 450°C, up to about 460°C, up to about 480°C, up to about 490°C, up to about 500°C, up to about 520°C, up to about 540°C, up to about 560°C, or up to about 580°C. As used herein, for example, an intermediate fraction having a lower limit of 160°C and an upper limit of 490°C can be referred to as a fraction or cut of 160°C to 490°C. Embodiments herein also contemplate that the intermediate fraction is hydrocarbons having from and / or up to the above ranges intermediate temperatures.

[0048] According to the fractionation mechanism, the middle distillate hydrocarbon“cut” can be relatively clean, meaning that the middle distillate can not have any substantial (>1 wt%) compounds boiling below the intended boiling temperature target limit and / or can not have any substantial (>1 wt%) compounds boiling above the intended boiling temperature target limit. For example, a 160°C to 490°C cut can not have any substantial hydrocarbon compounds boiling below 160°C or above 490°C. In other embodiments, the intended target“cut” temperature described above can be 5 wt% or 15 wt% boiling temperature of the lower limit and / or 95% or 85% boiling temperature of the upper limit, such as can be measured using ASTM D86 or ASTM D2887, or measured according to true boiling point (TBP) analysis of ASTM D2892 (e.g., ASTM D7169) for heavy streams, such as those streams boiling above about 400°C. In such embodiments, there can be at most 5 wt% or at most 15 wt% of compounds above and / or below the“cut” point temperature, respectively.

[0049] In some embodiments, the heavy fraction can include hydrocarbons having a boiling point above about 350°C, above about 375°C, above about 400°C (e.g., a >400°C+ fraction), above about 420°C, above about 440°C, above about 460°C, above about 480°C, above about 490°C, above about 500°C, above about 510°C, above about 520°C, above about 530°C, above about 540°C, above about 560°C, above about 580°C, above about 590°C, above about 600°C (e.g., a 600°C+ fraction), or above about 700°C. Embodiments herein also contemplate that the heavy fraction is hydrocarbons having a boiling point above an intermediate temperature of the above temperatures.

[0050] According to the fractionation mechanism, the heavy hydrocarbon“cut” can be relatively clean, meaning that the heavy distillate can not have any substantial (>1 wt%) compounds boiling below the intended boiling temperature target. For example, a 490°C+ cut can not have any substantial hydrocarbon compounds boiling below 490°C. In other embodiments, the intended target“cut” temperature described above can be 95% boiling temperature, or in other embodiments 85% boiling temperature, such as can be measured using ASTM D86 or ASTM D2887, or measured according to true boiling point (TBP) analysis of ASTM D2892 (e.g., ASTM D7169) for heavy streams, such as those streams boiling above about 400°C. In such embodiments, there can be at most 5 wt% or at most 15 wt% of compounds below the“cut” point temperature, respectively.

[0051] While the following examples are given with respect to limited temperature ranges, it is contemplated that any of the temperature ranges specified above can be used in the processes described herein. In addition, with respect to cut points, those mentioned in the examples below can be neat, as described above, or can refer to 5% or 15% boiling point temperature as a lower limit, or can refer to 85% or 95% boiling point temperature as an upper limit.

[0052] After fractionation, the light fraction, such as the 160°C- fraction, can be fed to the steam cracker section of the system with or without further processing. The light fraction fed to the steam cracker section can include, for example, light naphtha and lighter hydrocarbons, and in some embodiments can include heavy naphtha boiling range hydrocarbons.

[0053] The mid-range hydrocarbon fraction can be conditioned using one or more fixed bed reactors, such as hydrofinishing and / or hydrocracking reactors, each of which can destructively hydrogenate the hydrocarbons in the mid-fraction. The conditioning reactors can include catalysts for metal removal, desulfurization, denitrification, and the conditioning in these reactors can collectively add hydrogen to the hydrocarbon components so that they are more easily processed downstream to produce petrochemical products. For example, the fixed bed catalyst system in the mid-fraction conditioning zone can contain different layers of demetallization, destructive hydrogenation, and mesoporous zeolite hydrocracking catalysts to optimize the conversion of heavy materials to achieve a balance between a highly paraffinic stream suitable for olefin products and an aromatic-rich stream suitable for aromatic products.

[0054] In some embodiments, it can be desirable to further fractionate the mid-fraction into a mid-low fraction and a mid-high fraction. For example, a mid-fraction having a boiling range of 160°C to 490°C can be fractionated into a mid-low fraction having a boiling range of from about 160°C to about 325°C and a mid-high fraction having a boiling range of about 325°C to about 490°C. Thus, the conditioning flows can be configured to more selectively convert the hydrocarbon components in the respective low fraction and mid-high fraction to the desired conditioned effluent, where each flow can be configured based on the preferred catalyst for destructively hydrogenating the hydrocarbons therein, the reactor size for the expected feed volume and catalyst life, and the operating conditions to achieve the desired conversion to naphtha range containing steam cracker feedstock. Similarly, fractionating the mid-fraction into three or more sub-fractions is also contemplated.

[0055] Processing heavy hydrocarbons, such as 490 °C+ hydrocarbons, in a solvent deasphalting unit can increase the conversion of low value streams to higher value products. The solvent deasphalting unit can further provide more benefits, such as the ability to match the operating length of the conditioning reactor to the steam cracker, and the ability to process a wider range of feedstocks and different crudes, allowing the operator to adjust the process. The resulting solvent deasphalted oil can then be further processed, conditioning the deasphalted oil for use in a steam cracker system. However, it is recognized that the life of the hydrofinishing and / or hydrocracking catalysts can be negatively impacted by the heavier components, such as when the feed includes components having a boiling point above 565 °C.

[0056] The crude conditioning section aims to achieve four (4) objectives. First, the crude conditioning section can be used to increase the concentration of paraffins and naphthenes in the crude oil. Second, the conditioning section can reduce the concentration of polynuclear aromatics (PNA) in the crude oil. Third, the conditioning section can reduce the final boiling point (FBP) of the crude oil to below 540 °C. And, fourth, the conditioning section can minimize the vacuum residue fraction of the crude oil.

[0057] For example, when conditioning the middle distillate and heavy (deasphalted oil) fractions, embodiments herein can target the conversion of the heavier hydrocarbons to form lighter hydrocarbons than diesel. The hydrofinishing and hydrocracking catalysts and operating conditions can therefore be selected to target the conversion of the hydrocarbons or the hydrocarbons in the respective fractions to primarily (>50 wt%) naphtha range hydrocarbons. In one or more embodiments, the hydrofinishing and hydrocracking catalysts and operating conditions can therefore be selected to target the conversion of the hydrocarbons or the hydrocarbons in the respective fractions to primarily (>50 wt%) steam crackerable products. The use of catalysts and operating conditions in the conditioning section that target lighter hydrocarbon products can improve the operability of the steam cracker and the production of chemicals.

[0058] In some embodiments, the conditioning of a heavy fraction, such as a 490 °C+ fraction, can result in the conversion of at least 70 wt% of compounds having a boiling point above 565 °C to lighter boiling point compounds. Other embodiments can result in the conversion of greater than 75 wt%, greater than 80 wt%, or greater than 85 wt% of compounds having a boiling point above 565 °C to lighter boiling point compounds.

[0059] In some embodiments, the conditioning of a middle fraction, such as a 160 °C to 490 °C fraction, can result in the conversion of greater than 50 wt% of the hydrocarbons therein to naphtha range hydrocarbons. In other embodiments, the conditioning of the middle fraction can result in the conversion of greater than 55 wt%, greater than 60 wt%, or greater than 65 wt% or greater than 70 wt% of the hydrocarbons therein to naphtha range hydrocarbons.

[0060] In some embodiments, the co-regulation of the middle distillate and heavy distillate can result in greater than 50 wt% of the total hydrocarbons being converted to naphtha range hydrocarbons. In other embodiments, the regulation of the middle distillate and heavy distillate can result in greater than 55 wt%, greater than 60 wt%, or greater than 65 wt% of the hydrocarbons being converted to naphtha range hydrocarbons.

[0061] As a result of such initial separation and regulation, in some embodiments, the feed to the steam cracker can be fed directly to the steam cracker without further processing. In some embodiments, the light distillate having the preferred properties, including one or more of boiling point, API, BMCI, hydrogen content, nitrogen content, sulfur content, viscosity, MCRT, or total metal content, can be fed directly to the steam cracker after separation. The effluent from the middle distillate regulation can also be fed directly to the steam cracker according to embodiments herein. Likewise, in some embodiments, the effluent from the heavy distillate regulation can be fed directly to the steam cracker.

[0062] Even when processing multiple feeds of different boiling ranges, the regulation of the respective distillates as described herein can allow the steam cracker to run for extended periods of time. In some embodiments, the steam cracker can be capable of continuous operation for at least three years; in other embodiments at least four years; in yet other embodiments at least five years.

[0063] Further, the initial hydrocarbon distillate points, reactor size, catalyst, etc. can be regulated or configured such that the run time of the steam cracker operation and regulation process can be consistent. The catalyst, reactor size, and conditions can be configured such that the run time of the regulation unit is consistent with the run time of the steam cracker. The catalyst loading, catalyst type, and reaction severity can all play a role in determining the run time of the regulation unit. Further, the degree of regulation of the heavier hydrocarbons in the crude oil can impact the coking in the thermal cracker. To maximize the plant uptime, embodiments herein consider the design and configuration of the entire system such that for a given feedstock or multiple anticipated feedstocks, the regulation system has a similar expected run time as the steam cracker. Further, embodiments herein consider regulating the reaction conditions (T, P, space velocity, etc.) in the regulation section and / or the steam cracker based on the feedstock being processed such that the run time of the regulation section and the steam cracker are similar or consistent.

[0064] Adjustment of run times can minimize downtime, such as in cases where catalyst turnover in the conditioning reactors is performed concurrently with decoking of the steam cracker. When the conditioning system includes multiple reactors or reactor types, adjustment of run times can be based on expected steam cracker performance. Further, for example, in cases where a hydrofining unit can have significantly longer run times than the hydrocrackers in the conditioning section, parallel reactor flows and / or bypass processing can be used such that the total run times of the conditioning and steam cracking units can be uniform.

[0065] Bypass processing can include, for example, temporary processing of 490°C+ fractions in reactors that typically process lighter feedstocks. Heavier feedstocks are expected to have more stringent conditions and shorter catalyst life, so temporary processing of heavy oil in a mid-range hydrocarbon conditioning reactor during heavy catalyst changeover can allow full crude feed to continue to be fed to the steam cracker without shutdown while the heavy conditioning reactor catalyst is changed. The configuration of the mid-range conditioning reactors can also take into account expected bypass processing when designing the overall system for uniform run times.

[0066] Reference is now made to Figure 1 , which shows a simplified process flow diagram for a system for converting whole crude oil and heavy hydrocarbons according to embodiments herein.

[0067] In one or more embodiments, the desalted crude oil 1 can be processed in the feed treatment system 10 to produce one or more chemical streams 23 and a higher boiling pyrolysis oil fraction 25.

[0068] As an example of a feed treatment system 10, a wide boiling range heavy hydrocarbon feed, such as desalted crude oil 1, can be fed to a separation system 3. The separation system 3 can be an integrated separation plant (ISD), as described above and including, for example, separation and thermal integration. In the separation system 3, the desalted crude oil 1 can be separated into three fractions, including (a) a 160°C- fraction 5, which requires no conditioning and can be used as feed to the steam cracker section 7, (b) a 160°C to 490°C fraction 9, which can be upgraded in a conditioning section 11 to produce lighter hydrocarbons, such as a highly paraffinic hydrocarbon stream 13 suitable for processing in the steam cracking section 7, and (c) a 490°C+ fraction 15, which contains the most difficult to melt materials in the crude oil, and which can also be upgraded in the conditioning section 11 to produce lighter hydrocarbons, such as a highly paraffinic hydrocarbon stream 13 suitable for processing in the steam cracking section 7. In one or more embodiments, the 490°C+ fraction 15 is a solvent deasphalting system 17 in conjunction with a hydrofiner and / or a hydrocracker 27. Other fraction points can also be used to transport desired fractions and hydrocarbons therein to desired units for conditioning and / or cracking. The solvent deasphalting system 17 can produce asphalt 19 and deasphalted oil 21, which are suitable for further processing in a conditioning system to produce additional hydrocarbons suitable for conversion to chemicals in the steam cracker section 7. Processing of the feed in the steam cracker section can result in one or more chemical streams 23, such as ethylene, propylene, and butylenes, among others, and a higher boiling pyrolysis oil fraction 25. Other process schemes within the feed treatment system 10 can be used depending on desired fraction points, quality of the desalted crude oil feedstock, desired products, and other factors.

[0069] In some embodiments, the mid-cut (160°C to 490°C) stream can first be processed in a fixed bed conditioning system 27. The 490°C+ stream can be processed in a solvent deasphalting system 17, which can include one or more solvent deasphalting units, to produce deasphalted oil. The deasphalted oil can be further processed in a conditioning section 11, which can include the same reactors used to condition the mid-cut, as shown, or a separate fixed bed conditioning system, which can contain catalysts suitable for effectively conditioning the deasphalted oil received from the solvent deasphalting system. The reaction product 13 from the fixed bed conditioning reactor 27 can then be co-processed in a steam cracker section 7 to convert to light olefins and other valuable chemicals. The asphalt can be processed in one or more downstream processes (not shown).

[0070] Reference is now made to Figure 2 , which shows a simplified process flow diagram of a system for converting whole crude oil and heavy hydrocarbons to produce ethylene, in accordance with embodiments herein, in which like numbers indicate like components.

[0071] A wide boiling range heavy hydrocarbon feed, such as desalted crude oil 1, can be fed to a feed treatment system 10. The feed treatment system 10 can include an integrated separation device (ISD) 3 as described above, and includes, for example, separation and thermal integration. In the ISD 3, the desalted crude oil 1 can be separated into three fractions, including (a) a 160°C- fraction 5, which requires no conditioning and can be used as feed to a steam cracker section 7, (b) a 160°C to 490°C fraction 9, which can be upgraded in a conditioning section 11 to produce lighter hydrocarbons, such as a highly paraffinic hydrocarbon stream 13 suitable for processing in the steam cracker 7, and (c) a 490°C+ fraction 15, which can also be upgraded in the conditioning section 11 to produce lighter hydrocarbons, such as a highly paraffinic stream 13 suitable for processing in the steam cracker 7. In addition to the highly paraffinic stream 13, the conditioning section 11 can also produce asphalt 19, which can include the most difficult to melt materials in the crude oil, and which can be further processed or sent to a residual fuel oil pool as desired.

[0072] The conditioning section 11 can be used to treat the mid boiling fraction 9, the high boiling fraction 15, or both, in one or more hydroprocessing steps to produce a highly paraffinic hydrocarbon stream 13, which can be a hydrofinished effluent stream, or a hydrotreated mid boiling fraction stream, or a hydrotreated resid fraction stream, or a combination thereof. Other fraction points can also be used, if necessary, to transport desired fractions and hydrocarbons therein to desired units for conditioning, cracking, or both. Processing of the highly paraffinic stream 13 in the steam cracker 7 can produce one or more chemical streams 23, such as ethylene, propylene, butylenes, and other C4 and C4+ components, as well as higher boiling pyrolysis oil 25. Although not shown, the pyrolysis oil 25 can be recycled to the conditioning section 11 for further upgrading to chemicals 23.

[0073] One or more chemical streams 23 can be fed to a first separator 30 to recover a light fraction stream 32, which can include ethylene and propylene, and a heavy fraction 33, which can include butylenes, isobutylene, and other C4 and C4+ components including aromatics. The light fraction stream 32 can be recovered as a product, while the heavy fraction 33 can be fed to a second separator 34. The second separator 34 can separate the heavy fraction 33 into an overhead fraction 35, which can include butylenes, isobutylene, and other C4 components, and a bottoms fraction 36, which includes C4+ components and aromatics. The bottoms fraction 36 can be further separated to recover an aromatics stream and a non-aromatics stream, which is recycled to one or more of the ISD 3, the conditioning section 11, and the steam cracker 7 for further upgrading to high value products (not shown). The aromatics stream can be fed to the steam cracker 7 for further upgrading to high value products (not shown).

[0074] The overhead fraction 35 can be sent to a dimerization reaction system 40. The dimerization reaction system 40 can include a number of processing units not specifically shown. For example, the dimerization reaction system 40 can include one or more separators, one or more reactors (which can be fixed bed, ebullated bed, or catalytic distillation reactors), and one or more internal recycle lines as known in the art. In one or more embodiments, the overhead fraction 35 sent to the dimerization reaction system 40 can first be separated to recover an isoolefin fraction, such as an isobutylene fraction. A hydrogen (H2) stream 41 can be fed to the dimerization reaction system, and the dimerization reaction system 40 can include one or more reactors containing one or more catalysts configured to selectively hydrogenate any dienes present in the overhead fraction 35, producing additional n-butenes, butanes, and isobutenes. The one or more reactors containing one or more catalysts can use H2from the hydrogen stream 41 as the source of hydrogen for the selective hydrogenation reactions.

[0075] The dimerization reaction system 40 can also contain one or more catalysts for dimerizing the isobutylene to diisobutylene as previously described. Following reaction in an upstream reactor, such as a fixed bed reactor, the effluent from the primary fixed bed reactor can be fed to a catalytic distillation column reactor to separate the reaction products while simultaneously targeting complete conversion of the isobutylene. Embodiments herein contemplate that the dimerization reaction continues in the catalytic distillation column reactor.

[0076] Following dimerization of the isobutylene in the overhead fraction 35 to produce diisobutylene, the n-butenes and butanes present in the overhead fraction 35 can be separated from the dimerization products in the dimerization reaction system 40, producing a C4 product stream 42 and a dimerization product stream 44. The C4 product stream 42 can be recycled to one or more of the ISD 3, the conditioning section 11, the steam cracker 7, and the first separator 30 for further upgrading to high value products (not shown). In one or more embodiments, the C4 product stream 42 can be recovered as a product and sent to one or more downstream processes, such as a metathesis process (not shown) for conversion to propylene. While described with respect to isobutylene dimerization, one of ordinary skill in the art will appreciate that other dimerization processes can be utilized.

[0077] The dimerization product stream 44, which can primarily contain diisobutylene, can then be fed to a total hydrogenation system 50. The total hydrogenation system 50 can include a number of processing units not specifically shown. For example, the total hydrogenation system 50 can include one or more separators, one or more reactors (which can be fixed bed, ebullated bed, or catalytic distillation reactors), and one or more internal recycle lines as known in the art. The total hydrogenation system 50 can react the diisobutylene in the dimerization product stream 44 with hydrogen 52 in the presence of a hydrogenation catalyst to form a hydrogenated product stream 54 containing isooctane.

[0078] The hydrogenated product stream 54 can then be sent to a thermal cracking reaction system 60. The thermal cracking reaction system 60 can include a number of processing units not specifically shown. For example, the thermal cracking reaction system 60 can include one or more separators, one or more reactors (which can be fixed bed, ebullated bed, or catalytic distillation reactors), and one or more internal recycle lines as known in the art. The isooctane in the hydrogenated product stream 54 can be thermally cracked in the thermal cracking reaction system 60 to produce one or more cracked products 62. These cracked products can include one or more of H2, methane, ethylene, propylene, n-butenes, iso-butenes, and other components.

[0079] The cracked products 62 can be separated and recovered within the hydrocracking reaction system 60 as individual components, or can be sent to a tail separation system (not shown) as an entire product stream. In either embodiment, the recovered H2 stream can be recycled to one or more of the hydrocracking reactors in the hydrocracking reaction system 60, recycled and combined with the hydrogen stream 41, recycled and combined with the hydrogen stream 52, or collected as a product. The ethylene and propylene in the cracked product stream 62 can be combined with the ethylene and propylene in stream 32 and collected as high value products. A portion of the n-butenes and iso-butenes can be recycled and combined with the overheads 35 as additional feed or diluent to a dimerization process. A portion of the n-butenes and iso-butenes can also be combined with the C4 product stream 42 and sent to one or more downstream processes. Any components heavier than C4 that can be present in the cracked products 62 can be recycled to the chemicals stream 23 for additional upgrading or can be collected and sent to another downstream process as desired.

[0080] As described with respect to Figure 1 and Figure 2 The separation system 3 can include separation and heat integration as shown in Figure 3 After desalting, the crude oil 1 can be further preheated in the convection section of a heater 500 to produce a preheated crude oil 502. The preheated crude oil 502 can be fed to a separator 504, which can facilitate separation of a 160°C- fraction 5 from heavier components recovered in stream 506.

[0081] The remaining 160°C+ crude oil fraction 506 can be fed to a pump 508 which produces a pressurized 160°C+ crude oil fraction 510 which can then be fed to a heat exchanger 512. The ISD heat exchanger 512 can preheat the 160°C+ crude fraction 510 against the hot hydrogen stripper bottoms product 520 producing a pressurized and preheated 160°C+ crude fraction 514. The pressurized and preheated 160°C+ crude fraction 514 can then be fed back to the heater 500 where it is heated to facilitate the separation of the 160°C to 490°C fraction from the heavier 490°C+ fraction. The heated 160°C+ crude fraction 516 can then be fed to a hot hydrogen stripper 518. In the hot hydrogen stripper 518, the 160°C+ crude fraction is further separated into a 160°C to 490°C fraction 9 and a hot hydrogen stripper bottoms product 520 which contains the heavier 490°C+ hydrocarbons. The hot hydrogen stripper bottoms product 520 can be removed from the separation system 3 as a 490°C+ fraction 11 after being cooled by indirect heat exchange with the pressurized 160°C+ crude fraction 510 in the heat exchanger 512.

[0082] The hot hydrogen stripper 518 can utilize a hydrogen feed 522 as a stripping medium. The hot hydrogen stripper 518 can be operated to provide a wide range of flexibility based on the properties of the crude oil feedstock being processed. The stripper overhead, i.e., the 160°C to 490°C fraction 9, can be cooled to recover hydrogen gas and sent to an intermediate hydroprocessing reaction stage as appropriate and as described with respect to Figure 1 and Figure 2 After amine refining (not shown), the recovered hydrogen gas can be fed to a downstream pressure swing adsorption (PSA) unit (not shown) to increase the hydrogen gas purity. The PSA hydrogen gas product can be compressed in a make-up hydrogen compressor (not shown) to provide make-up hydrogen to one or more hydroprocessing reactors (not shown) Figure 1 ) and as the hot hydrogen gas feed 522.

[0083] The hot hydrogen stripper bottoms product 520, such as the 490°C+ fraction, contains the most difficult compounds that must be processed in the crude oil, including asphaltenes, metals, and CCR. Excess metals, CCR, and asphaltenes in the high boiling point residual fraction can cause rapid fouling of the catalyst and increase the pressure drop in a fixed bed downflow reactor, limiting conversion and catalyst run time. The 490°C+ stream 11 can be recovered and processed in a liquid circulating, ebullated bed residual hydrocracker along with any additional low value refinery streams, such as a tar stream and / or an oil slurry stream, after the pressurized 160°C+ crude fraction 510 is cooled, as described in Figure 1 .

[0084] By adjusting the amount of hydrogen 522 fed to the hot hydrogen stripper column 518, as well as the operating conditions of the hot hydrogen stripper 518 and the heater 500, the hydrocarbon fractions can be adjusted so that the light fraction 5 can be fed directly to a downstream steam cracker, and the middle fraction 9 can have little or no harmful compounds that would quickly foul a fixed bed conditioning reactor. In this way, the separation system 3 (with the hot hydrogen stripper column 518) can concentrate the most difficult to handle hydrocarbons in the heavy fraction 11, which can be fed to an ebullated bed reactor that can be operated under the most severe conditions, thus preserving the catalysts in the steam cracker and the fixed bed conditioning reactor.

[0085] As described above, embodiments herein can be used to convert the heavier fractions of crude oil into high value chemicals, and can minimize the amount sent to a residual fuel oil pool, which provides profitability.

[0086] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these systems, devices, methods, processes, and compositions belong.

[0087] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0088] As used herein and in the appended claims, the words "comprise," "have," and "include" and all grammatical variations thereof are each intended to have an open, non-limiting meaning that does not preclude the addition of more elements or steps.

[0089] "Optionally" means that the subsequently described event or circumstance can or can not occur. The description includes instances where the event or circumstance occurs and instances where it does not.

[0090] When the word "about" or "approximately" is used, the term can mean an amount that is within ±10%, within ±5%, within ±2%, within ±1%, within ±0.5%, within ±0.1%, or within ±0.01% of a value.

[0091] Ranges can be expressed as from about one particular value to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value to the other particular value, as well as all the particular values and combinations of the ranges.

[0092] Although the present disclosure includes a limited number of embodiments, those skilled in the art having benefit of the present disclosure will appreciate that other embodiments can be devised without departing from the scope of the present disclosure. Accordingly, the scope should be limited only by the appended claims.

[0093] While only a few example embodiments have been described in detail, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible without materially departing from the novel teachings and advantages of the application. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and also cover structures performing the same functions. Similarly, any step-plus-function clauses contained in the claims are intended to cover the acts described herein as performing the recited function and also cover the corresponding functions performed by the acts. Applicant expressly reserves the right to amend this specification to expressly apply 35 U.S.C. § 112(f) to any claim in this specification, where such a claim format is legally permissible.

Claims

1. A process for converting crude oil and other heavy hydrocarbon streams to produce ethylene, the process comprising: The crude oil is separated into at least a light boiling point fraction, a medium boiling point fraction, and a high boiling point residue fraction; The medium-boiling fraction, the high-boiling fraction, or both are processed in one or more hydrotreating steps to produce a hydrotreated medium-boiling fraction, a hydrotreated residue fraction, or both. The hydrotreated medium-boiling fraction, the hydrotreated residue oil fraction, or both, and the light-boiling fraction are fed into the steam cracker. Recovery of light fractions including C1-C4 hydrocarbons and pyrolysis oil; The light fraction is fed into the first separator and the C1-C3 stream and the mixed C4 and C4+ streams, including isoolefins, olefins and dienes, are recovered. The mixed C4 and C4+ streams, comprising isoolefins, olefins, and dienes, are fed into a second separator and the mixed C4 stream, comprising isoolefins, olefins, and C4+ streams, is recovered. The mixed C4 stream is dimerized in a dimerization unit to produce a dimerization product stream; The dimerization product stream is hydrogenated in a total hydrogenation system to produce a hydrogenated dimerization product stream; as well as The hydrogenated dimerization product stream is pyrolyzed in a pyrolysis reactor system comprising one or more pyrolysis reactors to produce one or more of hydrogen, methane, ethylene, propylene, n-butene, and isobutene.

2. The process according to claim 1, wherein dimerization comprises: The mixed C4 stream and hydrogen stream, comprising isoolefins, olefins and dienes, are fed into a first separator to separate the isoolefins and dienes from the olefins; The isoolefin and the diene are fed into a selective hydrogenation unit to convert the diene into olefins and isoolefins, producing a partially hydrogenated C4 stream. The partially hydrogenated C4 stream is fed into a fixed-bed reactor system containing a catalyst to produce a reactor effluent comprising a dimer of the isoolefin and unreacted C4. The reactor effluent is fed into a product splitter to produce a top distillate stream comprising unreacted C4 olefins and isoolefins, and a bottom product comprising the dimerization product stream.

3. The method according to claim 1, wherein separating the whole crude oil comprises: The crude oil is fed into a heater to produce preheated hydrocarbon feedstock; The preheated hydrocarbon feedstock is separated into light boiling point fraction and middle fraction in a separator; The middle fraction is fed back to the heater to produce a heated middle fraction. The hydrogen stream is fed into the hot hydrogen stripping tower; The heated middle fraction is separated into the medium-boiling-point fraction and the bottom fraction of the hot hydrogen stripping column in the hot hydrogen stripping column; as well as The high-boiling-point residue fraction is produced by cooling the bottom fraction of the hot hydrogen stripping tower via indirect heat exchange with the middle fraction.

4. The process according to claim 1, wherein processing the high-boiling-point fraction further comprises: The high-boiling-point fraction is fed into the solvent deasphalting unit to produce deasphalted oil fraction and asphalt fraction.

5. The process according to claim 4, further comprising destructively hydrogenating the medium-boiling fraction and the deasphalted oil fraction to produce the hydrotreated medium-boiling fraction, the hydrotreated residue oil fraction, or both.

6. The process according to claim 1, wherein hydrogenating the dimerization product stream in the hydrogenation unit comprises: The dimerization product stream is fed together with a hydrogen stream into the total hydrogenation system to convert the dimerization product stream of the isoolefin into an alkane, wherein the alkane includes isooctane.

7. The process of claim 2, further comprising recycling a portion of the unreacted C4 olefins and isoolefins to the selective hydrogenation unit, the dimerization unit, the hydrocracking reactor system, or a combination thereof.

8. The process according to any one of claims 1 to 7, wherein the pyrolysis further comprises processing the hydrogen dimerization product stream in a conditioning system, the conditioning system comprising one or more pyrolysis reactors configured to pyrolyze the hydrogen dimerization product stream to produce one or more of hydrogen, methane, ethylene, propylene, n-butene, and isobutene.

9. The process of claim 8, further comprising recycling a portion of the hydrogen to one or more hydrocracking reactors in the hydrocracking reaction system.

10. The process of claim 8, further comprising recycling a portion of the hydrogen gas as part of the hydrogen gas flow to the dimerization unit.

11. The process of claim 8, further comprising recycling a portion of the hydrogen to the total hydrogenation unit.

12. The process of claim 8, further comprising combining the ethylene and the propylene C1-C3 streams.

13. The process of claim 8, further comprising recycling a portion of the n-butene and isobutene to the dimerization unit.

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