Systems and methods for producing olefin products

Abstract

Systems and processes for producing an olefin product from a hydrocarbon feedstock are described. The system may be a steam cracking plant capable of receiving ethane from an ethane source, ethane / propane from an ethane / propane source, propane / butane from a propane / butane dehydrogenation plant, or a combination thereof. Methods of producing hydrocarbon products are also described.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] none. Background of the Invention A. Technical field

[0002] The present invention generally relates to systems and methods for producing hydrocarbon products from hydrocarbon feedstocks. The system may include a steam cracking unit capable of receiving ethane, optional propane and / or a dehydrogenated propane / butane composition. The steam cracking unit is connected to a feed preparation unit and an optional propane / butane dehydrogenation unit. B. Background Technology

[0003] Olefins, such as ethylene, are building blocks for a wide variety of commercially valuable polymers. Naturally occurring sources of olefins are not available in commercial quantities. Therefore, polymer producers rely on methods that convert more abundant lower alkanes into olefins. The preferred method for today's commercial-scale producers is steam cracking, a highly endothermic process in which steam-diluted alkanes are briefly subjected to temperatures of at least 800°C. The need for fuel to generate the required temperatures and the need for equipment that can withstand them significantly increase the overall cost. In addition, high temperatures promote the formation of coke and its accumulation within the system, resulting in the need for expensive periodic reactor shutdowns for maintenance and decoking.

[0004] Methods and systems for producing olefins from crude oil have been described. For example, International Patent Application No. WO2017 / 133975 by Ward et al. describes an integrated method for converting crude oil into petrochemical products, which includes crude oil distillation, hydrocracking, and steam cracking to produce petroleum products. Some methods use a mixed feed cracker (MFC). MFC can process light hydrocarbons such as ethane, propane, and butane, to naphtha, to heavy liquid feedstocks such as diesel and hydrocracking residues to produce gasoline and most petrochemical industrial products. AMFC methods can be operated based on an optimized downstream value chain between the supply of oil or natural gas as a feedstock and the market price of high value-added hydrocarbon products. However, the disadvantage of mixed feed steam crackers is that they cannot convert all feedstocks into olefins. The performance of the cracker can be optimized when a compatible feed is supplied. In most steam crackers, a dedicated furnace is usually required to achieve optimal ethane cracking. This leads to differences in the type and size of the furnace. Steam cracking causes coke (a type of carbon) to slowly deposit on the reactor walls. Decoking requires isolating the furnace from the process and then passing a stream of steam or a steam / air mixture through the furnace coils. This converts the hard, solid carbon layer into carbon monoxide and carbon dioxide. Once this reaction is complete, the furnace is returned to service. Because a lot of coking occurs within the MRC when ethane is cracked, an MRC typically requires at least two compatible furnaces to crack ethane, which affects the size of the furnaces in the MRC and makes the process less efficient and more expensive.

[0005] Systems and methods for producing hydrocarbon products have been described. For example, U.S. Patent No. 11,180,706 to Al-Sayed et al. describes an olefin production configuration. The process progressively separates crude oil into light and heavy fractions, which can then be upgraded using a fixed bed hydroconverter, a fluidized catalytic converter, or a residue hydrocracking unit. The upgraded stream can be fed to a steam cracker to produce olefins. The performance of this process is poor, which increases the capital cost of the overall process and reduces profitability.

[0006] In general, while technologies to produce petrochemicals such as olefins exist, they are energy inefficient and costly. Summary of the invention

[0007] A discovery can provide a solution for at least one of the problems associated with producing petrochemical products from crude oil. In one aspect, the discovery can include a system connected to a steam cracker, which provides an ethane / propane source, a butene / propylene source or both. The butene / propylene source can be a butane / propane dehydrogenation unit located downstream of the steam cracker. The device can provide a higher ethylene selectivity / conversion rate by providing a hydrogen-rich feed (such as ethane, ethylene, propane, propylene), and butane, butene or their mixture is sent to the steam cracker. In addition, this arrangement can also increase the amount of other hydrocarbons (such as naphtha, diesel, etc.), which can be sent to the steam cracker or made into other petroleum products (such as fuels, lubricants, etc.). In some aspects, the device can also make the total conversion rate of crude oil to petrochemical products reach at least 50%, preferably 65%, and more preferably at least 70%.

[0008] In one aspect of the present invention, a system and method for producing hydrocarbon products (e.g., olefins) are described. The system for producing hydrocarbon products may include a feed preparation unit, a steam cracking unit, and an ethane and / or propane feed stream conduit. The feed preparation unit is capable of producing a hydrocarbon feed stream containing liquefied petroleum gas (LPG), hydrocarbons, or mixtures thereof, and a fuel / asphalt stream from crude oil. The feed preparation unit, which may also be referred to as a crude oil processing unit, may be connected to the steam cracking unit so that the hydrocarbon feed stream can be transported to the steam cracking unit. The steam cracking unit is capable of cracking hydrocarbons, preferably ethane and / or propane, to produce ethylene and / or propylene. The ethane and / or propane feed stream conduit may be separated from the hydrocarbon feed stream and is capable of transporting ethane and / or propane to the steam cracking unit. On the other hand, the system may also include a propane / butane dehydrogenation unit connected to the steam cracking unit. The propane / butane dehydrogenation unit is capable of providing propylene and butenes to the steam cracking unit. A circulating propane / butane pipeline may be connected to the steam cracking unit and the propane / butane dehydrogenation unit. Propane, butane or both can be transferred from the steam cracking unit to the propane / butane dehydrogenation unit through a circulating propane / butane pipeline. The propane / butane conduit can provide additional propane, butane or a mixture thereof to the propane / butane dehydrogenation unit. In some aspects, the feed preparation unit is connected to the propane / butane dehydrogenation unit. The feed preparation unit can provide propane, butane or a mixture thereof to the propane / butane dehydrogenation unit.

[0009] Another aspect of the present invention describes a method for producing olefins. The method may include passing a hydrocarbon feed stream including a mixture of liquefied petroleum gas (LPG) and / or high boiling hydrocarbons and a second gaseous feed stream including ethane, propane or a mixture thereof through steam cracking conditions sufficient to produce olefin products. The hydrocarbon feed stream may include liquefied petroleum gas, hydrocarbons, or a combination thereof. In some aspects, the second gaseous feed stream may mainly include ethane, butane, or a mixture thereof feed stream (e.g., at least 50wt.% ethane, at least 75wt.% ethane, at least 99wt.% ethane, at least 50wt.% butane, at least 75wt.% butane, at least 99wt.% butane, or at least 50wt.% of a combination of ethane and butane, at least 75wt.% of a combination of ethane and butane, or at least 99wt.% of a combination of ethane and butane), which is obtained from a source different from LPG and / or higher boiling hydrocarbons. Steam cracking conditions can include a temperature of 600°C to 1000°C and a pressure of 0.1MPa to 0.5MPa. In some aspects, steam cracking conditions can produce a first (C3 / C4) hydrocarbon stream, which can include propane, butane or a combination thereof. A first (C3 / C4) hydrocarbon stream, a second (C3 / C4) hydrocarbon stream including propane, butane or a combination thereof, or a combination of a first (C3 / C4) hydrocarbon stream and a second (C3 / C4) hydrocarbon stream can be subjected to conditions suitable for producing a dehydrogenated C3 / C4 composition (e.g., propylene, isobutylene, butadiene, butene or a combination thereof). In some aspects, a crude oil feed can be subjected to conditions suitable for producing a hydrocarbon feed stream. This treatment can include producing a third (C3 / C4) hydrocarbon stream from a crude oil feedstock, which includes propane, butane or a combination thereof. The third (C3 / C4) hydrocarbon stream can be combined with a second (C3 / C4) hydrocarbon stream and subjected to suitable conditions to produce a dehydrogenated propane / butane composition. Crude oil conditions can also produce fuel and / or asphalt from crude oil, which can be separated to produce fuel compositions and asphalt compositions. The fuel compositions can include diesel, kerosene, gas oil or their mixtures. The olefin products produced by steam cracking include ethene, propylene or their mixtures.

[0010] Another aspect of the present invention discloses a system and method for producing hydrocarbons (e.g., ethylene and / or propylene). The system may use at least two, three, four or more steam cracking units, which may be placed in parallel, in series or in combination. The advantage of such a unit is that the conversion rate of crude oil into petrochemical products such as ethylene and / or propylene can reach at least 50%, preferably 65%, more preferably at least 70%, 80%, 90% or more. The system may include a feed preparation unit that is capable of producing a hydrocarbon feed stream containing liquefied petroleum gas (LPG), hydrocarbons or mixtures thereof, and a fuel / asphalt stream from crude oil; a first steam cracking unit that is located downstream of the feed preparation unit and connected to the feed preparation unit and is capable of cracking hydrocarbons from the hydrocarbon feed stream, preferably ethane and / or propane, to produce a C2 / C3 product stream containing ethylene and / or propylene, and a second steam cracking unit that is capable of cracking hydrocarbons from the hydrocarbon feed stream and / or hydrocarbons from the C2 / C3 product stream. The second steam cracking unit may be located downstream of the feed preparation unit and connected to the feed preparation unit, or may be located downstream of the first steam cracking unit and connected to the first steam cracking unit. In one aspect, the second steam cracking unit may be located downstream of the feed preparation unit and connected thereto, wherein the first steam cracking unit is capable of cracking a first portion of a hydrocarbon feed stream, and the second steam cracking unit is capable of cracking a second portion of the hydrocarbon feed stream. In another aspect, the second steam cracking unit may be located downstream of the first steam cracking unit and connected thereto, wherein the second steam cracking unit is capable of cracking hydrocarbons from a C2 / C3 product stream produced by the first steam cracking unit. A method for producing ethylene and / or propylene using a system having two or more steam cracking units is also disclosed.

[0011] The coupling may be in direct fluid communication with the coupling device or in indirect fluid communication with the coupling device.

[0012] The application discusses other embodiments of the present invention in full. Any embodiment discussed for one aspect of the present invention is also applicable to other aspects of the present invention, and vice versa. Each embodiment described herein should be understood as an embodiment applicable to other aspects of the present invention. It is conceivable that any embodiment or aspect discussed herein can be combined with other embodiments or aspects discussed herein and / or implemented for any method or composition of the present invention, and vice versa. In addition, the composition of the present invention can be used to realize the method of the present invention.

[0013] The following includes definitions of various terms and phrases used in this specification.

[0014] The term "C# hydrocarbons", where # is a positive integer, is intended to describe all hydrocarbons having # carbon atoms. Furthermore, the term "C#+ hydrocarbons" is intended to describe all hydrocarbon molecules having # or more carbon atoms. Thus, "C2+" hydrocarbons refers to a mixture of hydrocarbons having 2 or more carbon atoms. Thus, the term "C2+ alkanes" relates to alkanes having 2 or more carbon atoms.

[0015] "Cracking" refers to the process of breaking down organic compounds and reorganizing the molecules to produce more molecules than the original ones. During cracking, a series of reactions occur, accompanied by the transfer of hydrogen atoms between molecules. For example, naphtha can undergo thermal cracking to form ethylene and hydrogen.

[0016] "Hydrocarbons" are generally defined as molecules consisting primarily of carbon and hydrogen atoms. Hydrocarbons may also include other elements, such as, but not limited to, halogens, metallic elements, nitrogen, oxygen, and / or sulfur. Hydrocarbon fluids may include, entrain, or be entrained in non-hydrocarbon fluids, such as hydrogen, nitrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, water, and / or ammonia.

[0017] The term "about" or "approximately" is defined as close to, as understood by one of ordinary skill in the art. In a non-limiting embodiment, the term is defined as within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0018] The terms "wt. %, "vol. %" or "mol. %" refer to the weight percent of a component, the volume percent of a component or the mole percent of a component, respectively, based on the total weight, the total volume or the total number of moles of the material including the component. In a non-limiting example, 10 grams of a component in 100 grams of a material is 10 wt. % of the component.

[0019] The term "substantially" and variations thereof are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.

[0020] The terms "inhibit" or "reduce" or "prevent" or "avoid" or any variation of these terms when used in the claims and / or specification include any measurable reduction or complete inhibition to achieve a desired result.

[0021] The term "effective" as used in this specification and / or claims means sufficient to achieve a desired, intended, or expected result.

[0022] In the claims or description, when "a" or "an" is used in conjunction with the terms "includes," "comprising," "containing," or "having," it may mean "one," but is also consistent with the meaning of "one or more," "at least one," and "one or more."

[0023] The words "comprise" (and any form of including, such as "comprises" and "comprises"), "have" (and any form of having, such as "have" and "has"), "include" (and any form of including, such as "includes" and "include"), or "contain" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0024] The systems and methods of the present invention may "comprise," "consist essentially of," or "consist of" particular ingredients, components, compositions, etc. disclosed throughout the specification. With respect to the transitional phrase "consist essentially of," in one non-limiting aspect, a fundamental and novel feature of the systems and methods of the present invention is that they enable the production of petrochemical products (e.g., olefins, such as ethylene or propylene) from crude oil in a cost- and energy-efficient manner.

[0025] Other objects, features and advantages of the present invention will become apparent from the following drawings, detailed descriptions and examples. However, it should be understood that although the drawings, detailed descriptions and examples show specific embodiments of the present invention, they are given by way of illustration only and are not intended to be limiting. In addition, it is contemplated that from this detailed description, those skilled in the art will clearly understand the changes and modifications within the spirit and scope of the present invention. In further embodiments, the features of a particular embodiment may be combined with the features of other embodiments. For example, the features of one embodiment may be combined with the features of any other embodiment. In further embodiments, additional features may be added to the particular embodiments described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Advantages of the present invention will become apparent to those skilled in the art from the following detailed description with reference to the accompanying drawings.

[0027] FIG. 1 shows an example of a system for producing olefin products including a steam cracking unit coupled to an ethane / propane feed source.

[0028] FIG. 2 shows another embodiment of a system for producing olefin products, which includes a propane / butane dehydrogenation unit coupled to a steam cracker.

[0029] FIG. 3 shows another embodiment of a system for producing olefin products, which includes a feed preparation unit coupled to a propane / butane dehydrogenation unit coupled to a steam cracking unit.

[0030] 4A and 4B illustrate an embodiment of another system for producing olefin products, the system comprising two steam crackers, one of which is placed in parallel with the other steam cracker (FIG. 4A) and one of which is placed in series with the other steam cracker (FIG. 4B).

[0031] Although the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the accompanying drawings. The drawings may not be drawn to scale. In addition, the schematic diagrams shown in Figures 1-4 can be combined with each other, for example, to create a more robust method for producing various petrochemical products from crude oil. DETAILED DESCRIPTION

[0032] A discovery can provide a solution to at least one of the problems associated with producing petrochemical products from crude oil. In one aspect of the invention, a hydrocarbon feed obtained from crude oil and a separate alkane feed (e.g., a feed mainly containing (i.e., 50wt.% or more, 60wt.% or more, 70wt.% or more, 80wt.% or more, 90wt.% or more, or 99wt.% or more of ethane and / or butane) can be sent to a steam cracking unit to produce petroleum products. The advantage of this device is that more hydrogen can be supplied to the steam cracking unit, thereby increasing the output of ethylene and propylene. In addition, this allows more crude oil processing to be used for the production of fuel. These and other non-limiting aspects of the present invention will be discussed in further detail in the following sections with reference to the accompanying drawings.

[0033] Referring to FIG. 1 , a system 100 for producing olefin products is described. The system 100 may include a feed preparation unit 102 and a steam cracking unit 104. Crude oil 108 enters the feed preparation unit 102. Crude oil is unrefined petroleum extracted from a geological formation. The term crude oil may also include oil that has been subjected to water-oil separation and / or gas-oil separation and / or desalting and / or stabilization treatment. Non-limiting examples of crude oil include Arab heavy crude oil, Arab light crude oil, other Gulf crude oil, Brent crude oil, North Sea crude oil, North African and West African crude oil, Indonesian crude oil, Chinese crude oil, West Texas crude oil and mixtures thereof, and also include shale oil, oil sands, condensate and bio-based oil. The crude oil used as feed for the method of the present invention is preferably conventional oil, and its API gravity is greater than 20°API (measured according to ASTMD287 standard). On the one hand, the crude oil used in the method of the present invention is a light crude oil with an API gravity greater than 30°API; on the other hand, the crude oil used in the method of the present invention may include Arab light crude oil. The API gravity of Arab light crude oil is generally between 32-36° API and the sulfur content is between 1.5-4.5wt.%. Crude oil can be separated into different crude oil fractions according to the difference in boiling point. For example, a fractionation tower or a combination of multiple fractionation towers can be used to distill crude oil, and the fractionation tower is used to separate crude oil into fractions by fractionation. The resulting crude oil can be processed in an atmospheric distillation unit to separate gas oil and lighter fractions from high boiling point components to obtain a mixed hydrocarbon feed 110. The hydrocarbon feed may include hydrocarbons having a boiling point higher than 560°C. Non-limiting examples of various fraction hydrocarbon feeds having a boiling point higher than 560°C include vacuum gas oil, middle distillate oil, naphtha, kerosene, and liquefied petroleum gas. The distilled hydrocarbons can be converted into additional feeds for fuels and / or steam cracking units. Asphalt 112 can also be produced by the feed preparation unit 102. The fuel stream 110 can leave the feed preparation unit 102 and be sold, transported, or further processed. The bitumen stream 112 may exit the feed preparation unit 102 and be further processed.

[0034] The hydrocarbon feed 114 may leave the feed preparation unit 102 and enter the steam cracking unit 104. The hydrocarbon feed may include ethane, propane, butane, naphtha, distillate, or any combination thereof. The second gaseous hydrocarbon stream 116 may enter the steam cracking unit 104. The second gaseous hydrocarbon stream 116 may include ethane, propane, or a mixture thereof. The second gaseous hydrocarbon stream 116 may include 50 wt.% or more, 60 wt.% or more, 70 wt.% or more, 80 wt.% or more, 90 wt.% or more, or 99 wt.% or more of ethane or butane or a combination of ethane and butane. In the steam cracking unit 104, the hydrocarbon feed 114 and the second gaseous hydrocarbon feed 116 can be steam cracked at a temperature of 600°C to 770°C (e.g., 600°C, 625°C, 650°C, 675°C, 700°C, 725°C, 950°C, 770°C, or any value or range therebetween) and / or a pressure of 0.2 MPa to 0.3 MPa (e.g., 0.2 MPa, 0.21 MPa, 0.22 MPa, 0.23 MPa, 0.24 MPa, 0.25 MPa, 0.26 MPa, 0.27 MPa, 0.28 MPa, 0.30 MPa, or any value or range therebetween). During the steam cracking process, saturated hydrocarbons are decomposed into smaller, usually unsaturated hydrocarbons, such as ethylene and propylene, by diluting the mixed hydrocarbon feed with steam and heating the mixture in a furnace in the absence of oxygen. The residence time of the steam cracking reaction can be as high as 50 to 1000 milliseconds. The mixed steam cracker may have a fractionation unit (not shown) or a gas fractionation unit (not shown) capable of separating the olefin product stream from other products (e.g., butane, propane, etc.). Such fractionation units are well known in the art. The olefin product stream 118 may leave the mixed feed steam cracker 104 and be stored, transported, or used in other processing units.

[0035] With reference to FIG. 2 , additional hydrogen-rich olefins (e.g., propylene and / or butenes) may be provided to the steam cracker 104 from a propane / butane dehydrogenation unit 106. The propane / butane dehydrogenation unit 106 may receive a first C3 / C4 alkane stream 202 from the steam cracker 104, a second C3 / C4 alkane stream 204 from a propane and / or butane source, or a combination thereof. The C3 / C4 alkane stream may include propane, butane, or a mixture thereof. The ratio of C3 to C4 alkanes in the C3 / C4 stream may be from 0.1 to 99.9 to 99.9 to 0.1, and may vary according to the requirements of the steam cracker, the propane / butane dehydrogenation unit, or both. The amount of propane and / or butane in the C3 / C4 stream may be at least 50 wt.% or more, 60 wt.% or more, 70 wt.% or more, 80 wt.% or more, 90 wt.% or more, or 99 wt.% or more (propane and / or butane). In some embodiments, C3 / C4 alkanes may be provided to the propane / butane dehydrogenation unit 106 in the form of separate streams (e.g., C3 stream and C4 stream). In the propane / butane dehydrogenation unit, propane, butane or a mixture thereof may be dehydrogenated to propylene, butene or a mixture thereof (e.g., propylene, isobutylene, butene, butadiene, etc.). The dehydrogenated propylene / butene (C3 / C4 olefin) stream 206 may leave the propane / butane dehydrogenation unit and enter the steam cracking unit 104. The dehydrogenation conditions may include a pressure in the range of 500°C to 1000°C, 0 to 1379 kPa, and a space velocity of 0.1 to 10 hr-1 weight hourly space velocity (WHSV). A portion of the dehydrogenated propylene / butene (C3 / C4 olefin) stream 206 may be provided to other processing units, storage, or transportation. In some embodiments, the C3 / C4 alkane stream 202 may be considered a recycle stream between the steam cracker and the propane / butane dehydrogenation unit because sufficient C3 / C4 alkanes may not be produced before providing the dehydrogenated propylene / butenes to the steam cracker.

[0036] In the steam cracking unit 104, the second gaseous hydrocarbon stream 116 can primarily include ethane (e.g., at least 50 wt.%, 60 wt.%, 70 wt.%, 80 wt.%, 90 wt.%, 91 wt.%, 92 wt.%, 93 wt.%, 94 wt.%, 95 wt.%, 96 wt.%, 97 wt.%, 98 wt.%, 99 wt.%, or 100 wt.% ethane, or any range or value therebetween). In the steam cracking unit 106, gaseous ethane, optional propane, dehydrogenated propane / butane composition (e.g., propylene and butene) can be diluted with steam and heated in one or more furnaces to a temperature of 775°C to 860°C (e.g., 775°C, 800°C, 825°C, 850°C, 860°C, or any value or range therebetween) and / or a pressure of 0.2MPa to 0.3MPa (e.g., 0.2MPa, 0.21MPa, 0.22MPa, 0.23MPa, 0.24MPa, 0.25MPa, 0.26MPa, 0.27MPa, 0.28MPa, 0.30MPa, or any value or range therebetween) to produce olefins and hydrocarbon products. The steam cracking unit 104 can include one or more separation units that can separate propane, butane, or a mixture thereof from olefin products and other hydrocarbon products. The separated propane and / or butane can form a second propane / butane product stream. The olefin product stream 118 can exit the mixed feed steam cracker 104 and be stored, transported, or used in other processing units. In some embodiments, the olefin product stream 118 can have an increased amount of ethylene and / or propylene compared to steam cracking of a hydrocarbon feed in the absence of additional ethane, propane, and / or butane.

[0037] With reference to Figure 3, the system of Fig. 2 has been described, wherein propane and / or butanes are provided to the propane / butane dehydrogenation unit from the feed preparation unit. In system 3, the 3rd C3 / C4 hydrocarbon stream 302 can be produced from the feed preparation unit by separating propane and / or butanes from distillate, gas oil, vacuum gas oil, naphtha or residual oil. The 3rd C3 / C4 alkane stream 302 can leave the feed preparation unit 102 and combine with the first C3 / C4 alkane stream 202 (shown), directly offer to the propane / butane dehydrogenation unit (not shown), or their combination. In some aspects, the C3 / C4 alkane stream 302 is offered to the steam cracking unit 104 (not shown).

[0038] With reference to Fig. 4A, this is the system of Fig. 1, with additional steam cracking unit. Specifically, the first steam cracking unit 104a and the second steam cracking unit 114b are placed in parallel with each other. The first part of hydrocarbon feed 114 can be processed by the first steam cracking unit 104a, and the second part of hydrocarbon feed 114 can be processed by the second steam cracking unit 104b. This may be advantageous for producing additional olefin product stream 118. In addition, the second hydrocarbon gas stream 116 (not shown) can be removed from the system in Fig. 4A. Alternatively, another hydrocarbon gas stream 116 can be sent to the second steam cracking unit 104b (not shown). The system in Fig. 4A can include three, four or more steam cracking units, which can be placed in parallel or in series with each other, or placed in a combination of parallel or series.

[0039] Referring to FIG. 4B , this is the system of FIG. 1 with an additional steam cracking unit. Specifically, the first steam cracking unit 104a and the second steam cracking unit 104b are placed in series with each other. The second steam cracking unit 104b is located downstream of the first steam cracking unit 104a. This arrangement allows any uncracked hydrocarbons in the product stream 118 to be further cracked in the second steam cracking unit 104b. Compared with the product stream 118, the product stream 118b can have a higher olefin product content because the uncracked hydrocarbons in 118 are subjected to another round of cracking in the second steam cracking unit 104 (b). This may be advantageous for producing additional olefin products (e.g., ethylene and / or propylene). In addition, the second hydrocarbon gas stream 116 (not shown) can be removed from the system in FIG. 4B. Alternatively, another hydrocarbon gas stream 116 can be sent to the second steam cracking unit 104b (not shown). The system in FIG. 4B may include three, four or more steam cracking units, which can be placed in parallel or in series with each other, or placed in a combination of parallel or series.

[0040] Although the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the spirit and scope of the embodiments defined in the appended claims. In addition, the scope of the present application is not limited to the specific embodiments of the methods, machines, manufactures, material compositions, devices, methods and steps described in the specification. It is easy for a person of ordinary skill in the art to understand from the above disclosure that existing or later developed processes, machines, manufactures, material compositions, devices, methods or steps that perform substantially the same functions as the corresponding embodiments described herein or achieve substantially the same results can be utilized. Therefore, the attached claims are intended to include these processes, machines, manufactures, material compositions, devices, methods or steps within their scope.

Claims

1. A method for producing olefins, characterized in that The process comprises subjecting a hydrocarbon feed stream comprising liquefied petroleum gas (LPG), hydrocarbons or mixtures thereof and a second gaseous feed stream comprising ethane, propane or mixtures thereof to steam cracking conditions sufficient to produce olefin products.

2. The method according to claim 1, characterized in that The hydrocarbons include naphtha, gas oil, distillates or mixtures thereof.

3. The method according to any one of claims 1 to 2, characterized in that Wherein the second gaseous feed stream is obtained from a source different from the hydrocarbon feed.

4. The method according to any one of claims 1 to 3, characterized in that The steam cracking conditions include a temperature of 600°C to 1000°C and a pressure of 0.1 MPa to 0.5 MPa.

5. The method according to any one of claims 1 to 4, characterized in that wherein the crude oil is subjected to conditions to produce a hydrocarbon feed.

6. The method according to claim 5, characterized in that The crude oil is processed through various conditions to produce fuel and / or asphalt.

7. The method according to claim 6, characterized in that The fuel comprises diesel, kerosene, gasoline or a mixture thereof.

8. The method according to any one of claims 1 to 7, characterized in that The olefin products produced by steam cracking include ethylene, propylene, C4 hydrocarbons or mixtures thereof.

9. The method according to any one of claims 1 to 8, characterized in that Wherein the second gaseous feed stream comprises at least 50 wt.% ethane or propane, or a mixture thereof, preferably the second gaseous feed stream comprises at least 50 wt.% ethane.

10. The method according to claim 9, characterized in that Wherein the steam cracking conditions produce a first (C3 / C4) hydrocarbon stream comprising propane, butane, or a combination thereof.

11. The method according to claim 10, characterized in that wherein the first (C3 / C4) hydrocarbon stream, the second (C3 / C4) hydrocarbon stream comprising propane, butane or a combination thereof, or the combination of the first (C3 / C4) hydrocarbon stream and the second (C3 / C4) hydrocarbon stream are subjected to conditions suitable for dehydrogenating propane and / or butane, and wherein the dehydrogenated propane and / or butane are subjected to steam cracking conditions.

12. The method according to any one of claims 1 to 11, characterized in that Also included is subjecting the crude oil feed to conditions suitable for producing a hydrocarbon feed stream and a third C3 / C4 hydrocarbon feed stream, preferably wherein the third C3 / C4 feed stream is subjected to conditions for dehydrogenating propane and / or butanes, and wherein the dehydrogenated propane and / or butanes are subjected to steam cracking conditions.

13. The method according to any one of claims 1 to 12, characterized in that Also included is subjecting the produced olefin product to a second steam cracking step in a separate steam cracking unit to increase the amount of the olefin product produced.

14. The method according to any one of claims 1 to 13, characterized in that Also included is subjecting a first portion of the hydrocarbon feed stream to steam cracking conditions and subjecting a second portion of the hydrocarbon feed stream to a second steam cracking step, wherein the first portion is cracked in a first steam cracking unit and the second portion is cracked in a second steam cracking unit.

15. A system for producing hydrocarbon products, characterized in that: The system comprises: a feed preparation unit capable of producing a hydrocarbon feed stream comprising liquefied petroleum gas (LPG), hydrocarbons or mixtures thereof, and a fuel / asphalt stream from crude oil; a steam cracking unit capable of cracking hydrocarbons (preferably ethane and / or propane) to produce ethylene and / or propylene, wherein the feed preparation unit is connected to the steam cracker unit so that the hydrocarbon feed stream can be transported to the steam cracker unit; and an ethane and / or propane feed stream conduit, which is separated from the hydrocarbon feed stream and capable of transporting ethane and / or propane to the steam cracker unit.

16. The system according to claim 15, characterized in that Further comprising a propane / butane dehydrogenation unit coupled to the steam cracker, the propane / butane dehydrogenation unit being capable of providing propylene and butenes to the steam cracker, and / or further comprising a circulating propane / butane pipeline coupled to the steam cracker and the propane / butane dehydrogenation unit, the circulating pipeline being capable of providing propane, butane or both from the steam cracker to the propane / butane dehydrogenation unit, and / or further comprising a propane / butane pipeline coupled to the propane / butane dehydrogenation unit and being capable of providing propane, butane or a mixture thereof to the propane / butane dehydrogenation unit, and / or wherein the feed preparation unit is also capable of producing propane, butane or a combination thereof from crude oil, and wherein propane, butane or a combination thereof can be provided to the propane / butane dehydrogenation unit.

17. The system according to any one of claims 15 or 16, characterized in that Further comprising at least a second steam cracking unit capable of cracking hydrocarbons, preferably ethane and / or propane, to produce ethylene and / or propylene.

18. The system according to claim 17, characterized in that The feed preparation unit is coupled to the second steam cracking unit such that at least a portion of the hydrocarbon feed stream can be fed to the steam cracking unit and a second portion of the hydrocarbon feed stream can be fed to the second steam cracking unit.

19. The system according to claim 18, characterized in that The second steam cracking unit is located downstream of the steam cracking unit, and the second steam cracking unit is connected to the steam cracking unit and is capable of receiving C2 / C3 products from the steam cracking unit.

20. A system for producing hydrocarbon products, characterized in that: The system comprises: a feed preparation device, which is capable of producing a hydrocarbon feed stream and a fuel / asphalt stream containing liquefied petroleum gas (LPG), hydrocarbons or a mixture thereof from crude oil; a first steam cracking device, which is located downstream of the feed preparation device and connected to the feed preparation device and is capable of cracking hydrocarbons (preferably ethane and / or propane) from the hydrocarbon feed stream to produce a C2 / C3 product stream containing ethylene and / or propylene; and a second steam cracking device, which is capable of cracking hydrocarbons from the hydrocarbon feed stream and / or hydrocarbons from the C2 / C3 product stream, wherein the second steam cracking device is located downstream of the feed preparation device and connected to the feed preparation device or is located downstream of the first steam cracking device and connected to the first steam cracking device.

21. The system according to claim 20, characterized in that wherein the second steam cracking unit is located downstream of and connected to the feed preparation unit, wherein the first steam cracking unit is capable of cracking a first portion of the hydrocarbon feed stream and the second steam cracking unit is capable of cracking a second portion of the hydrocarbon feed stream, and / or wherein the second steam cracking unit is located downstream of and connected to the first steam cracking unit, wherein the second steam cracking unit is capable of cracking hydrocarbons from a C2 / C3 product stream.

22. A method for producing ethylene and / or propylene, characterized in that: The method comprises using the system of any one of claim 20 or claim 21.

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