Process for converting very light low sulfur crude oil to chemicals

Abstract

The present disclosure relates to systems and processes for converting light or very light low sulfur crude oils and gas condensate to chemicals and petrochemical products. The process includes providing a hydrocarbon feedstock comprising a crude oil or gas condensate having an API specific gravity of at least 35, a sulfur content of less than 0.2 wt%, and hydrocarbons having a standard boiling point above 575 DEG C of less than 10 wt%. The hydrocarbon feedstock is heated and separated to recover a light fraction, a middle fraction, and optionally a heavy fraction. The light fraction is steam cracked to produce a cracked light fraction, and the middle fraction is steam cracked separately to produce a cracked middle fraction. The cleaved light fraction and the cleaved middle fraction are then separated to recover one or more product fractions, including an ethylene fraction and a propylene fraction.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to converting crude oil into olefins and other chemicals. Background Art

[0002] Crude oil processing usually requires conventional refining units (such as crude oil distillation) to separate various boiling range fractions for further downstream processing. Refining and petrochemical complexes are separate and operate independently of each other. The configuration of traditional and independent refineries is capital and energy intensive.

[0003] If the high boiling compounds in crude oil are sent to a steam cracker, they can cause significant operating problems. High boiling compounds tend to form coke, largely due to their high asphaltene content. Therefore, high boiling compounds are usually removed before the lighter fractions are sent to different petrochemical units, such as steam crackers or aromatic complexes.

[0004] However, the removal process increases the capital cost of the entire process and reduces profitability, as the removed high-boiling compounds can only be sold as low-value fuel oil. In addition, converting the vacuum residue without the formation of large amounts of heavy polynuclear aromatics (HPNA), which are harmful to the steam crackers downstream in the process, has been a challenge so far. HPNA leads to rapid coking in the steam crackers, which requires frequent decoking cycles, reducing the overall operating rate of the complex.

[0005] Additionally, the vacuum residue portion of crude oil is very deficient in hydrogen, which reduces the yield of valuable chemicals in the steam cracking furnace.

[0006] Generally speaking, a typical refinery plus petrochemical complex and other conventional processes for converting whole crude oil generally convert less than 50% of the crude oil into more desirable end products, such as petrochemical products such as ethylene, propylene, butenes, pentenes and light aromatics. Generally speaking, 20% of the whole crude oil is removed in advance during processing to remove the heaviest components that are difficult to convert. About another 20% of the whole crude oil is usually converted into pyrolysis oil, and about 10% is converted into methane. Summary of the invention

[0007] On the one hand, embodiments herein relate to a process for converting light or very light low sulfur crude oil and condensate into chemicals and petrochemical products. The process includes providing a hydrocarbon feedstock, the hydrocarbon feedstock comprising a crude oil or condensate, the API gravity of which is at least 35, the sulfur content is less than 0.2wt%, and the hydrocarbon content with a standard boiling point higher than 575°C is less than 10wt%. The process also includes heating and separating the hydrocarbon feedstock to recover light fractions, middle fractions and optional heavy fractions. The light fraction is steam cracked to produce a cracked light fraction. The middle fraction is steam cracked to produce a cracked middle fraction. The cracked light fraction and the cracked middle fraction are then separated to recover one or more product fractions, the product fractions including an ethylene fraction and a propylene fraction.

[0008] In some embodiments, the light fraction and the middle fraction are steam cracked without any intermediate treatment. In embodiments where a heavy fraction is recovered, the process includes hydrotreating the heavy fraction to produce a converted heavy fraction having a higher hydrogen content than the heavy fraction, and steam cracking the converted heavy fraction to produce a cracked heavy fraction. The resulting cracked heavy fraction can then be separated from the cracked light fraction and the cracked middle fraction and collected to recover one or more product fractions.

[0009] In various embodiments, the one or more product fractions include a pyrolysis oil fraction. In such embodiments, the process may further include hydrotreating the heavy fraction and the pyrolysis oil fraction to produce a converted heavy fraction.

[0010] On the other hand, embodiments herein relate to a process for converting light or very light low sulfur crude oil and condensate into chemicals and petrochemical products. The process includes providing a hydrocarbon feedstock, the feedstock comprising a crude oil or condensate, the API gravity of which is at least 35, and the hydrocarbon content of the standard boiling point higher than 575°C is less than 10wt%. The hydrocarbon feedstock is heated and separated in one or more stages to recover light fractions, middle fractions and optional heavy fractions. The light fraction is steam cracked to produce a cracked light fraction. The middle fraction is hydrotreated to produce a converted middle fraction having a higher hydrogen content than the middle fraction, and then the converted middle fraction is steam cracked to produce a cracked middle fraction. The cracked light fraction is then separated from the cracked middle fraction to recover one or more product fractions, and the product fractions include an ethylene fraction and a propylene fraction.

[0011] In some embodiments, the light fraction is steam cracked without any intermediate treatment. In embodiments where a heavy fraction is recovered, the process includes hydrotreating the heavy fraction to produce a converted heavy fraction having a higher hydrogen content than the heavy fraction, and steam cracking the converted heavy fraction to produce a cracked heavy fraction. The resulting cracked heavy fraction can then be separated from the cracked light fraction and the cracked middle fraction and collected to recover one or more product fractions.

[0012] In various embodiments, the final boiling point of the light fraction is in the range of 160°C to 250°C, and the final boiling point of the middle fraction is in the range of 500°C to 540°C.

[0013] On the other hand, embodiments of the present invention relate to a system for converting light or very light sweet crude oil and condensate into chemicals and petrochemical products. The system includes a feed source containing a hydrocarbon feedstock, the hydrocarbon feedstock comprising crude oil or condensate, the API gravity of which is at least 35, the sulfur content is less than 0.2wt%, and the content of hydrocarbons with a standard boiling point higher than 575°C is less than 10wt%. A flow line can be provided for feeding the hydrocarbon feedstock to the convection coils of the cracking furnace to heat the hydrocarbon feedstock to produce a heated hydrocarbon feedstock. A separator is provided for separating the hydrocarbon feedstock to recover a light fraction and a residual liquid fraction. The convection coils of the second cracking furnace are provided for heating the residual liquid fraction to produce a heated residual fraction, and a second separator is provided for separating the heated residual fraction to recover an intermediate fraction and a heavy fraction. The radiant coils of the cracking furnace steam crack the light fraction to produce a cracked light fraction. The radiant coils of the second cracking furnace steam crack the intermediate fraction to produce a cracked intermediate fraction. The system further comprises a separation system for collectively separating the cracked light fraction and the cracked middle fraction to recover one or more product fractions including an ethylene fraction and a propylene fraction.

[0014] In some embodiments, the system further includes a hydrotreating unit for increasing the hydrogen content of the middle distillate downstream of the second separator and upstream of the radiant coils of the second cracking furnace.

[0015] In various embodiments, the system further comprises a hydroprocessing unit for increasing the hydrogen content of the heavy fraction to produce a hydrotreated heavy fraction. The radiant coils of the same or different cracking furnaces are arranged to steam crack the hydrotreated heavy fraction to produce a cracked heavy fraction. A flow line is also arranged to feed the cracked heavy fraction to a separation system to centrally separate a cracked light fraction, a cracked middle fraction and a cracked heavy fraction, thereby recovering one or more product fractions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1-4A simplified process flow diagram is shown of systems and processes according to one or more embodiments disclosed herein. DETAILED DESCRIPTION

[0017] As used herein, the term "petrochemicals" refers to hydrocarbons including light olefins and diolefins and C6-C8 aromatic compounds. Thus, petrochemicals refer to hydrocarbons including ethylene, propylene, butylenes, butadiene, pentenes, pentadienes, as well as benzene, toluene, and xylenes. With respect to a subset of petrochemicals, the term "chemicals" as used herein refers to ethylene, propylene, butadiene, 1-butene, isobutylene, benzene, toluene, and p-xylene.

[0018] Hydrofining is a catalytic process, usually carried out in the presence of free hydrogen, in which the main purpose when used to process hydrocarbon feedstocks is to remove various metal contaminants (e.g., arsenic), heteroatoms (e.g., sulfur, nitrogen, and oxygen), and aromatics from the feedstock. Typically, in hydrofining operations, the cracking of hydrocarbon molecules (i.e., breaking down larger hydrocarbon molecules into smaller hydrocarbon molecules) is minimized. The term "hydrofining" as used herein 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 a feed stream (e.g., atmospheric tower bottoms) through a reduction process. The hydrofining process can vary greatly depending on the type of feed to the hydrofining unit. For example, light feeds (e.g., naphtha) contain very few and very few types of impurities, while heavy feeds (e.g., atmospheric tower bottoms (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 handle than those present in light feeds. Therefore, hydroprocessing of light feeds is usually carried out at lower reaction severity, while heavy feeds require higher reaction pressures and temperatures.

[0019] Hydrocracking refers to the process of hydrogenation and dehydrogenation accompanied by hydrocarbon cracking / fragmentation, for example, converting heavier hydrocarbons to lighter hydrocarbons, or converting aromatics and / or cycloalkanes (cycloalkanes) to non-cyclic branched alkanes.

[0020] As used herein, "conditioning" and similar terms refer to converting hydrocarbons by one or both of hydrocracking and hydrofinishing. "Destructive hydrogenation" and similar terms refer to the cracking of hydrocarbon molecular bonds of hydrocarbons and the associated hydrogen saturation of the remaining hydrocarbon fragments, which can produce a stable lower boiling hydrocarbon oil product, and can include both hydrocracking and hydrofinishing.

[0021] "API Gravity" means the specific gravity of a petroleum feed or product relative to water as determined by ASTM D4052-11.

[0022] Embodiments herein relate to processes and systems that use crude oil (such as light or very light sweet crude oil) and / or low-value heavy hydrocarbons as feedstock and produce petrochemical products (such as light olefins (ethylene, propylene and / or butenes)) and aromatics. More specifically, embodiments herein relate to methods and systems for producing olefins and aromatics by thermal cracking of pre-regulated light sweet crude oil. Light sweet crude oil can be divided into light fraction, middle fraction and heavy fraction, each defined as follows. Then the process of embodiments herein can directly steam crack light fraction or middle fraction and heavy fraction. In certain embodiments, before the regulated middle fraction is fed to the steam cracker, the middle fraction can be regulated to improve the quality of the raw material. The heavy fraction as a small part of the light sweet crude oil can be discarded or can be further processed to produce a raw material for use as a steam cracker raw material.

[0023] The hydrocarbon mixture that can be used in the embodiments disclosed herein may include various hydrocarbon mixtures with a boiling point range, wherein the final boiling point of the mixture may be greater than 500°C, such as greater than 525°C, 550°C, or 575°C. The amount of high boiling hydrocarbons (e.g., hydrocarbons with a boiling point exceeding 550°C) may be as low as 0.1wt%, 1wt%, or 2wt%, but may be as high as 10wt%, 25wt%, 50wt%, or greater. This description is illustrated for crude oil (such as whole crude oil), but any hydrocarbon mixture with a high boiling point endpoint may be used. However, the process disclosed herein may be applied to crude oil, condensate, and hydrocarbons with a broad boiling point curve and an endpoint above 500°C. Such hydrocarbon mixtures may include whole crude oil, virgin crude oil, hydrotreated crude oil, 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, distillates, virgin naphtha, natural gas condensate, atmospheric pipeline distillation tower bottoms, vacuum pipeline distillation liquid streams including tower bottoms, wide boiling range naphtha to gas oil condensate, heavy non-virgin hydrocarbon streams from refineries, vacuum gas oil, heavy gas oil, atmospheric residue, hydrocracker wax, and Fischer-Tropsch wax, etc. In some embodiments, the hydrocarbon mixture may include hydrocarbons with boiling points ranging from the naphtha range or lighter to the vacuum gas oil range or heavier.

[0024] When the final boiling point of the hydrocarbon mixture may be very high, such as exceeding 550°C in some embodiments, the hydrocarbon mixture cannot be directly processed in a steam cracking furnace to produce olefins. The presence of these heavy hydrocarbons leads to the formation of coke in the furnace, wherein coking may occur in one or more of the convection zone preheating coils or superheating coils, in the radiation coils or in the transmission pipeline exchanger, and this coking may occur very quickly (such as within a few hours). Whole crude oil is usually not cracked commercially because it is not economical. Whole crude oil is usually fractionated, and only a specific portion is used for steam cracking heaters to produce olefins. The rest is used for other processes. The cracking reaction is carried out via a free radical mechanism. Therefore, high ethylene yields can be obtained when cracking at high temperatures. Lighter feeds, such as butane and pentane, require high furnace 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 a boiling point exceeding 550°C). Exposing whole crude oil to high temperatures without separation produces high yields of coke (a byproduct of severe cracking of hydrocarbons) and plugs the furnace. Steam cracking furnaces must be shut down periodically and the coke cleaned by steam / air decoking. The time between two cleaning periods when olefins are produced is called the run length. When whole crude oil is cracked without separation, coke is deposited on the convection section coils (evaporating fluid), the radiant section (where the olefin production reaction occurs), and / or the transmission line exchangers (where the reaction is quickly stopped by cooling to maintain olefin yield).

[0025] Although the process herein can be used for various hydrocarbon mixtures with a wide boiling point range, the embodiments herein are particularly advantageous for light or very light sweet crude oils. As used herein, the API gravity of light crude oil is at least 35, at least 40 in some embodiments, and the API gravity of very light crude oil is at least 42, at least 45 in some embodiments. Such feeds can additionally have a boiling point curve, wherein at least 90wt% of the material has a boiling point below 575°C. In addition, the sulfur content of light or very light sweet crude oil can be less than 0.2wt%, as well as having a low metal content and a low Conradson carbon content. Examples of suitable light sweet crude oils that can be used for embodiments herein may include, for example, Permian crude oil or West Texas light crude oil, Arabian or Agbami light crude oil, and other crude oils having a boiling point of less than 10wt% of materials above 575°C. The process herein can also be used to process condensates with very low high boiling point materials (>575°C).

[0026] Thus, embodiments herein relate to processes that utilize very light sweet crude oil or condensate as feedstock and produce chemicals and petrochemicals. The processes and systems herein may include a separation section, such as a HOPS (Heavy Oil Processing Scheme), integrated with a mixed feed steam cracker with optional hydrotreating or hydrofining for selected intermediate streams.

[0027] Light crude oil or condensate feed is separated and processed to deliver high quality steam cracker feed to the mixed feed steam cracker to maximize the percentage of valuable chemicals produced from a barrel of crude oil while maintaining a reasonable decoking frequency for the steam cracking heater. Due to the reduced amount of asphaltenes and micro carbon residues in the light crude oil or condensate, the formation of HPNA is controlled via small amount of bleed, rather than catalytic or thermal conversion.

[0028] According to embodiments of the present invention, the process and system may include a feed preparation section, for example, a desalter may be included. The desalted crude oil may then be separated into a light fraction, a middle fraction, and a heavy fraction. Crude oil and / or condensate are first separated into different fractions in a pre-separation section (such as a HOPS tower). As described above, the different fractions may include: a light fraction, whose final boiling point is in the range of about 200-250°C, which is rich in normal alkanes and is therefore a good steam cracking feedstock; a middle fraction, whose boiling point ranges from an initial boiling point of about 200-250°C to a final boiling point of 500-540°C, and the middle fraction contains materials in the distillate and gas oil range; and a heavy fraction (residue stream), which contains hydrocarbons with a boiling point higher than 500-540°C. The initial boiling points of the middle fraction and the heavy fraction are similar to the final boiling points of the light fraction and the middle fraction, respectively.

[0029] Although embodiments are described as including light fraction points below about 250°C (such as a 160°C fraction) and heavy fractions having a boiling point above about 500°C-540°C (such as a 520°C fraction), it should be noted that the actual fraction points may vary depending on the type of whole crude oil or other condensate fraction being processed. For example, for crude oils containing low metal or nitrogen content, or a large amount of "easy to process" components that boil at temperatures as high as 525°C, 540°C, or 565°C, it is possible to increase the mid / high fraction points while still achieving the advantages of the embodiments herein. Similarly, in some embodiments, the low / mid fraction points may be as high as 220°C, or as high as 250°C in other embodiments. According to the embodiments herein, the ability to change the fraction points can increase the flexibility of the process scheme, thereby allowing the processing of a variety of feeds while still producing a desired product mixture.

[0030] The 500-540°C+ residue portion of the crude oil is very deficient in hydrogen, which reduces the yield of valuable chemicals in the steam cracker. Removing this portion allows the steam cracker to operate stably and maintain high conversion to high-quality petrochemicals. By optionally hydrotreating or hydrofinishing the residue portion to increase the hydrogen content, the overall chemical yield per barrel of feedstock can be increased. Selectively hydrotreating or hydrofinishing on the 500-540°C+ stream provides the opportunity to recycle pyrolysis oil from the downstream mixed feed steam cracker to increase the overall conversion of the feed to chemicals while still limiting the heaviest molecules in the crude oil from entering the steam cracker to maintain high operating rates.

[0031] The light fraction is then sent to a steam cracker. Since the composition of the light fraction is rich in normal paraffins, the light fraction can be sent to the steam cracker without any intermediate treatment.

[0032] The middle fraction is also sent to the steam cracker. In some embodiments, the middle fraction may be sent to the steam cracker without any intermediate treatment. In other embodiments, the middle fraction is processed in a first hydroprocessing or hydrofinishing section, which may utilize a fixed bed hydroprocessing or hydrofinishing reactor operating at mild severity to increase the hydrogen content, and the effluent from the first hydroprocessing or hydrofinishing section is sent to the steam cracker.

[0033] Although "steam crackers" are generally mentioned above, the processes and systems herein may include one or more furnaces, each having one or more convection and radiation coils for preheating, superheating and thermal cracking of the respective feeds. In addition, the steam cracker or "steam cracker section" or "steam cracker zone" herein may include a quench system for rapidly cooling the effluent from the radiation coils, and a separation system, which may include one or more distillation columns for separating the steam cracker effluent into various hydrocarbon fractions, such as C2, C3, C4, naphtha, diesel, gas oil, vacuum gas oil, pyrolysis oil and residual fractions, etc., and combinations of two or more of these fractions, such as C2-C4 fractions.

[0034] In some embodiments, the light fraction and the middle fraction may be fed to separate heaters within the steam cracker section of the plant. In other embodiments, the light fraction and the middle fraction may be fed to separate coils of the same heater. Various other arrangements using separate or identical heaters for various feed fractions are also contemplated.

[0035] In some embodiments, the residual fraction (heavy fraction) is removed from the system and not further processed. In other embodiments, the residual fraction is sent to a hydrotreating or hydrofinishing step, where the hydrogen content of the heavy fraction is increased, and then sent to a steam cracking heater to produce chemicals, thereby increasing the overall production of total chemicals. Optionally, in the case of high value of ultra-low sulfur fuel oil, the hydrotreating or hydrofinishing step can be completely avoided, thereby further reducing CAPEX, OPEX and CO2 emissions.

[0036] As mentioned above, the separate parts of the plant, including separation, steam cracking and optional hydroprocessing or hydrofinishing modules, are deeply integrated, meaning that they are combined into one unit / technology. The operation and design of each module are tailored so that the products of each module either fit the subsequent block or meet the final goal of chemicals generated. In a traditional setup, such integration is not possible due to the different requirements of the intermediate products and the respective final products.

[0037] The difference between this and various other traditional technologies (such as integrated refineries) for converting crude oil into chemicals is optimization and integration, and the capital savings achieved thereby. If the goal is not to produce fuel products such as gasoline or diesel, most of the traditional refinery equipment required to make such fuel products is no longer needed, thereby reducing overall capital investment. The configuration disclosed herein also minimizes and / or eliminates the need for refinery auxiliary units (such as hydrogen production, amine regeneration, sulfur recovery, sulfur-containing wastewater stripping, etc.).

[0038] The deep integration of the early separation system (such as the two-stage HOPS system) with the mixed feed steam cracking heater reduces capital investment and improves the overall efficiency of the unit by optimizing heat recovery during the early separation process. The configuration in this article combines the energy requirements of the early crude oil separation to meet the downstream cracking heater vaporization requirements.

[0039] The system is designed to process very light, sweet crude oil feedstocks (with API about >45°) that have very little residual content (about 500-540°C+). Therefore, no dedicated conversion unit is required to upgrade the residual portion of the crude oil. Removal of this small residual fraction allows high operating rates to be achieved when designing mixed feed cracking heaters. Unlike conventional refineries that produce chemicals, the feed to the steam cracker is not limited to light components and naphtha, but the full range of molecules from naphtha to gas oil boiling point range are fed to the heater, and the heater and downstream system design can accommodate non-conventional feeds.

[0040] The embodiment of the above process is Figures 1 to 4 Each figure is described in the figure.

[0041] Figure 1 A configuration for processing very light sweet crude oil feedstock (API about> 45°) according to an embodiment of the present invention is shown. In this embodiment, a crude oil feedstock 10 is fed to a two-stage HOPS (heavy oil processing scheme) 12 to produce a light fraction 14, whose component boiling points are lower than about 200-250°C, an intermediate fraction 16, whose component boiling points are between about 200-250°C and 500-540°C, and an optional residue discharge fraction 18, whose component boiling points are higher than about 500-540°C. The light stream 14 is sent to a steam cracker section 20 including a cracking furnace, a quenching system, and a separation system without intermediate treatment because it is rich in normal alkanes and is therefore an excellent steam cracker feedstock. The intermediate fraction is also sent to a steam cracker section 20 and can be fed to a separate heater in the steam cracker section. After conversion in the cracking furnace, the resulting cracked product can be quenched and separated to recover one or more chemical streams 22.

[0042] Figure 2 A configuration for processing very light sweet crude oil feedstock (API about> 45°) according to some embodiments of the present invention is shown, wherein the same numerals represent the same components. In this embodiment, the crude oil feedstock 10 is fed to a two-stage HOPS (heavy oil processing scheme) 12 to produce a light fraction 14, whose components have a boiling point below about 200-250°C, an intermediate fraction 16, whose components have a boiling point between about 200-250°C and 500-540°C, and a residual fraction 18, whose components have a boiling point above about 500-540°C. The light stream 14 is sent to the steam cracker section 20 without intermediate treatment because it is rich in normal alkanes and is therefore an excellent steam cracker feedstock. The intermediate fraction 16 is also sent to the steam cracker section 20 and can be sent to a separate heater (not shown) within the steam cracker section. The residual fraction 18 is sent to a hydrotreating or hydrofinishing section 26, wherein the hydrogen content of the heavy fraction 18 is increased, and the resulting hydrotreated product 28 is then sent to a steam cracking heater within a steam cracker section 20 to produce chemicals 22, thereby increasing the overall production of all chemicals. Optionally, when the value of very low sulfur fuel oil is high, the hydrotreating or hydrofinishing step can be avoided entirely, and the heavy fraction 18 can be recovered as a blend or product stream 30 for use in producing very low sulfur fuel oil, resulting in even greater reductions in CAPEX, OPEX, and CO2 emissions. The pyrolysis oil 32 recovered while separating the cracked hydrocarbon products within the steam cracker section is fed to the hydrotreating or hydrofinishing step together with the residual fraction 18 of the crude feedstock, thereby increasing the overall conversion of the feedstock to chemicals.

[0043] Figure 3A configuration for processing a very light sweet crude feedstock (API>45°) according to some embodiments herein is shown, wherein like numbers represent like components. In this embodiment, a crude feedstock 10 is fed to a two-stage HOPS (heavy oil processing scheme) 12 to produce a light fraction 14, whose components have a boiling point below about 200-250°C, an intermediate fraction 16, whose components have a boiling point between about 200-250°C and 500-540°C, and a residual fraction 18, whose components have a boiling point above about 500-540°C. The light stream 14 is sent to a steam cracker section 20 without intermediate treatment. The intermediate fraction 16 is processed in a first hydroprocessing or hydrofinishing section 36, which may utilize a fixed bed hydroprocessing or hydrofinishing reactor operated under mild conditions to increase the hydrogen content; the effluent 38 from the first hydroprocessing or hydrofinishing section 36 is sent to the steam cracking section 20. The residual fraction 18 is sent to a hydrotreating or hydrofinishing section 26, wherein the hydrogen content of the heavy fraction 18 is increased, and the resulting hydrotreated product fraction 28 is then sent to a steam cracking heater in a steam cracker section n20 to produce chemicals 22, thereby increasing the overall production of chemicals. Optionally, when the value of very low sulfur fuel oil is high, the hydrotreating or hydrofinishing step can be completely avoided, and the heavy fraction 18 can be recovered as a blend or product stream 30 for use in the production of very low sulfur fuel oil, resulting in even greater reductions in CAPEX, OPEX and CO2 emissions. The pyrolysis oil 32 recovered while separating the cracked hydrocarbon products in the steam cracker section is fed to the hydrotreating or hydrofinishing step together with the residual fraction 18 of the crude feedstock, thereby increasing the overall conversion of the feedstock to chemicals.

[0044] Although Figure 3 36. It is not shown in the figure, but the hydroprocessing zone 26, 36 may include one or more hydroprocessing or hydrofinishing reactors and separation systems. The reactor contains a suitable catalyst to increase the hydrogen content of the hydrocarbons in the corresponding middle distillate or heavy distillate. Therefore, the reaction in the hydroprocessing or hydrofinishing reactor may include the above-mentioned various reactions, including hydrodesulfurization, hydrocracking, hydrodenitrogenation and other reactions for removing metals, heteroatoms and other pollutants while increasing the hydrogen content of the hydrogen molecules therein. After the reaction, the hydrotreated reaction product (hydrotreated middle distillate or hydrotreated heavy distillate) can be fed to the separation system to recover any unreacted hydrogen, acid gases, converted hydrocarbons and optionally residual liquids containing unconverted hydrocarbons that are not suitable for steam cracking.

[0045] Figure 4 shows that initially Figure 2An embodiment of processing very light sweet crude oil (such as Permian crude oil) in the manner described. In this embodiment, a two-stage HOPS (heavy oil processing scheme) 12 is used to separate crude oil 10 to produce a light fraction (naphtha fraction) 14, a middle fraction (AGO / VGO fraction) 16, and a residual fraction 18. The very light sweet crude oil 10 is fed to one or more heaters, such as convection coils 52 disposed in the convection section 50 of the cracking furnace. The heated crude oil 10H is then fed to the first stage separator 12A of the two-stage HOPS 12 and separated into the light fraction 14 and the residual liquid 54. The residual liquid 54 is then fed to one or more heaters, such as the convection coils 62 disposed in the convection section 60 of the cracking furnace and heated. The heated residual liquid 54H is then fed to the second stage separator 12B of the two-stage HOPS 12 and separated into the middle fraction 16 and the residual fraction 18. Depending on the amount of crude oil being processed, one or more heaters and HOPS may be used to produce and process the corresponding fractions, wherein the feeds fed to and received from the multiple heaters are represented by 10', 54' and 18'. Figure 4 As shown, a feed buffer tank 55 may be used to accumulate and distribute a plurality of residual liquid streams 54 , 54 ′ that may be received from a plurality of first stage HOPSs 12A and distribute the residual liquid 54 , 54 ′ to a plurality of heaters 60 and a plurality of second stage HOPSs 12B.

[0046] The light fraction 14 is sent to the steam cracker section 20 without intermediate treatment because it is rich in normal paraffins and is therefore an excellent steam cracker feed. For thermal cracking, the light fraction 14 can be heated and superheated in one or more convection coils 56 of the same or different heaters and then fed to the radiant coils 58 for rapid heating to the cracking temperature, producing a cracked light fraction 59.

[0047] In this embodiment, the middle distillate 16 is sent to a separate heater within the steam cracker section 20. For thermal cracking, the middle distillate 16 can be heated and superheated in one or more convection coils 66 of the same or different heaters and then fed to radiant coils 68 for rapid heating to cracking temperatures to produce a cracked middle distillate 69.

[0048] The residual fraction 18 is sent to a hydrotreating or hydrofinishing step 26, wherein the hydrogen content of the heavy fraction is increased, and the resulting hydrotreated product fraction 28 having improved crackability is then sent to a steam cracking heater (not shown) to produce chemicals, thereby increasing the overall production of chemicals. After hydrotreating, for example, the hydrotreated reaction effluent can be separated to recover unreacted hydrogen and hydrogen sulfide, hydrotreated hydrocarbons fed to the cracker section 20, and residual fuel oil 30' containing unconverted heavy hydrocarbons that are not suitable for thermal cracking.

[0049] The resulting cracked products, including the cracked hydrotreated fraction from stream 28, the cracked light fraction 59, and the cracked middle fraction 69, are fed to a separation zone of the steam cracker section 20 to recover light olefins including the pyrolysis oil 32 among other products.

[0050] Optionally, in cases where the value of ultra low sulfur fuel oil is high, the hydrotreating or hydrofinishing step can be avoided entirely, thereby further reducing CAPEX, OPEX and CO2 emissions. The pyrolysis oil 32 from the steam cracker section is fed to the hydrotreating or hydrofinishing step together with the residual fraction 18 of the crude oil feed.

[0051] Figure 4 Further illustrate that dilution steam is added to the light fraction and the middle fraction vapor fraction. In each heater (50, 60), water or steam 70 can be superheated in one or more convection coils 72 to produce superheated steam 74, which is mixed with heated raw materials (10H, 54H) and / or steam streams (light fraction 14 and middle fraction 16) to provide steam-diluted feed to the cracking coils. After mixing, steam and hydrocarbons can be superheated and sent to the radiant coils 58, 68 of the heater for cracking. Vapor fractions such as naphtha fractions, gas oil fractions or light hydrocarbon fractions and dilution steam mixtures are further superheated in the convection section (coils 56, 66) and enter the radiant coils (58, 68). The radiant coils can be located in different units, or a group of radiant coils in a single unit can be used for cracking hydrocarbons in the vapor fraction. The amount of dilution steam can be controlled to minimize total energy. Typically, the steam is controlled at a steam to oil ratio of about 0.5 w / w, with any value from 0.05 w / w to 1.0 w / w being acceptable, such as from about 0.3 w / w to about 0.7 w / w, or from about 0.1 w / w to 0.4 w / w.

[0052] The radiant coil technology can be of any type with an overall residence time ranging from 90 ms to 1000 ms with multiple rows and multiple parallel channels and / or split coil arrangements. They can be vertical or horizontal. The coil material can be high strength alloys with bare finned tubes or tubes with improved internal heat transfer. The heater can consist of one radiant box with multiple coils and / or two radiant boxes, each of the two radiant boxes having multiple coils. The geometry and size of the radiant coils and the number of coils in each box can be the same or different. If cost is not a factor, multiple flow heaters / exchangers can be employed.

[0053] After the radiant coils are broken, one or more transfer line exchangers can be used to cool the product very quickly and generate (ultra) high pressure steam. One or more coils can be combined and connected to each exchanger. The exchangers can be double tube or multi-tube shell and shell exchangers.

[0054] Direct quenching can also be used instead of indirect cooling. For this case, oil can be injected at the outlet of the radiant coil. After oil quenching, water quenching can also be used. Instead of oil quenching, full water quenching is also acceptable. After quenching, the product is sent to the recovery section.

[0055] As mentioned above, the embodiments of this article can be used to convert light sweet crude oil feed into chemicals while reducing and / or eliminating traditional refinery unit operations. Two-stage HOPS is used to separate crude oil into different fractions: light fraction, middle fraction and optional residual fraction that can be removed from the system. The light stream is sent directly to the steam cracker section to be converted into chemicals. The middle fraction can be sent directly to the steam cracker section, or can be optionally mildly hydrotreated or hydrofinished in a fixed bed reactor to increase the content of hydrogen and paraffins before being sent to the steam cracking section. The residual fraction can be the effluent of the system, or is sent to a hydrotreating or hydrofining step, wherein the hydrogen content of the heavy fraction is increased, and then is sent to a steam cracking heater to produce chemicals, thereby increasing the total output of all chemicals, or optionally as a very low sulfur fuel oil product when valuable.

[0056] Unless defined otherwise, all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art to which these systems, apparatuses, methods, processes, and compositions belong.

[0057] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0058] As used herein and in the appended claims, the words "comprising," "having," and "including" and all grammatical variations thereof are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps.

[0059] "Optionally" means that the subsequently described event or circumstance may or may not occur. The description includes instances where the event or circumstance occurs and instances where the event or circumstance does not occur.

[0060] When the word "about" or "approximately" is used, the term may mean that the value may vary by up to ±10%, up to 5%, up to 2%, up to 1%, up to 0.5%, up to 0.1%, or up to 0.01%.

[0061] Ranges can be expressed as from about one particular value to about another particular value, inclusive. When such a range is expressed, it should be understood that another embodiment is from the one particular value to the other particular value, as well as all the particular values ​​within the range and combinations thereof.

[0062] While the present disclosure includes a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the present disclosure. Accordingly, the scope should be limited only by the appended claims.

Claims

1. A process for converting light or very light sweet crude oil and condensate into chemicals and petrochemical products, the process comprising: Providing a hydrocarbon feedstock, the hydrocarbon feedstock comprising crude oil or condensate, wherein the crude oil or condensate has an API gravity of at least 35, a sulfur content of less than 0.2 wt%, and less than 10 wt% of hydrocarbons having a normal boiling point higher than 575° C.; heating and separating the hydrocarbon feedstock to recover a light fraction, a middle fraction, and optionally a heavy fraction; steam cracking the light fraction to produce a cracked light fraction; steam cracking the middle distillate to produce a cracked middle distillate; as well as The cracked light fraction and the cracked middle fraction are separated to recover one or more product fractions, including an ethylene fraction and a propylene fraction.

2. The process according to claim 1, wherein the light fraction and the middle fraction are steam cracked without any intermediate treatment.

3. The process according to claim 1, wherein a heavy fraction is recovered, the process comprising: hydrotreating the heavy fraction to produce a converted heavy fraction having a higher hydrogen content than the heavy fraction; as well as steam cracking the converted heavy fraction to produce a cracked heavy fraction; as well as The cracked heavy fraction is collectively separated from the cracked light fraction and the cracked middle fraction to recover the one or more product fractions.

4. The process of claim 3, wherein the one or more product fractions include a pyrolysis oil fraction, the process comprising hydrotreating the heavy fraction and the pyrolysis oil fraction to produce the converted heavy fraction.

5. The process of claim 2, wherein the hydrocarbon feedstock has an API gravity of at least 45.

6. A process for converting light or very light sweet crude oil and condensate into chemicals and petrochemical products, the process comprising: Providing a hydrocarbon feedstock, the hydrocarbon feedstock comprising crude oil or condensate, wherein the crude oil or condensate has an API gravity of at least 35 and contains less than 10 wt% of hydrocarbons having a normal boiling point higher than 575° C.; heating and separating the hydrocarbon feedstock to recover a light fraction, a middle fraction, and optionally a heavy fraction; steam cracking the light fraction to produce a cracked light fraction; hydrotreating the middle distillate to produce a converted middle distillate having a higher hydrogen content than the middle distillate; steam cracking the converted middle distillate to produce a cracked middle distillate; as well as The cracked light fraction and the cracked middle fraction are separated to recover one or more product fractions, including an ethylene fraction and a propylene fraction.

7. The process according to claim 6, wherein the light fraction is steam cracked without any intermediate treatment.

8. The process according to claim 6, wherein a heavy fraction is recovered, the process comprising: hydrotreating the heavy fraction to produce a converted heavy fraction having a higher hydrogen content than the heavy fraction; as well as steam cracking the converted heavy fraction to produce a cracked heavy fraction; as well as The cracked heavy fraction is collectively separated from the cracked light fraction and the cracked middle fraction to recover the one or more product fractions.

9. The process of claim 8, wherein the one or more product fractions include a pyrolysis oil fraction, the process comprising hydrotreating the heavy fraction and the pyrolysis oil fraction to produce the converted heavy fraction.

10. The process of claim 6, wherein the final boiling point of the light fraction is in the range of 160°C to 250°C, and the final boiling point of the middle fraction is in the range of 500°C to 540°C.

11. A system for converting light or very light sweet crude oil and condensate into chemicals and petrochemicals, the system comprising: A feed source containing a hydrocarbon feedstock, the hydrocarbon feedstock comprising crude oil or condensate, the crude oil or condensate having an API gravity of at least 35, a sulfur content of less than 0.2 wt%, and less than 10 wt% of hydrocarbons having a normal boiling point greater than 575°C; a convection coil of a cracking furnace, the convection coil for heating the hydrocarbon feedstock to produce a heated hydrocarbon feedstock; a separator for separating the hydrocarbon feedstock to recover a light fraction and a residual liquid fraction; convection coils of a second cracking furnace, the convection coils for heating the residual liquid fraction to produce a heated residual fraction; a second separator for separating the heated residual fraction to recover a middle fraction and a heavy fraction; a radiant coil of a cracking furnace, the radiant coil being used to steam crack the light fraction to produce a cracked light fraction; radiant coils of a second cracking furnace, the radiant coils being used to steam crack the middle distillate to produce a cracked middle distillate; as well as A separation system is used for collectively separating the cracked light fraction and the cracked middle fraction to recover one or more product fractions, wherein the product fractions include an ethylene fraction and a propylene fraction.

12. The system of claim 11, further comprising a hydrotreater for increasing the hydrogen content of the middle distillate downstream of the second separator and upstream of the radiant coils of the second cracking furnace.

13. The system according to claim 11, further comprising a hydrotreating unit for increasing the hydrogen content of the heavy fraction to produce a hydrotreated heavy fraction; radiant coils of the same or different cracking furnace, the radiant coils being used to steam crack the hydrotreated heavy fraction to produce a cracked heavy fraction; as well as A flow line is provided for feeding the cracked heavy fraction to the separation system so as to centrally separate the cracked light fraction, the cracked middle fraction and the cracked heavy fraction to recover the one or more product fractions.

14. The system of claim 11, further comprising a flow line for recovering the heavy fraction as low sulfur fuel oil.

15. The system of claim 13, wherein the separation system further produces a pyrolysis oil fraction, the system comprising a flow line for providing the pyrolysis oil fraction to the hydroprocessing unit.

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