Method and system for steam cracking of heavy hydrocarbons

Abstract

The invention relates to a method and a system for steam cracking of heavy hydrocarbon, which are characterized in that the heavy hydrocarbon enters a first gas-liquid separator to be separated, a first liquid-phase material obtained by separation and diluted steam are mixed and heated and then enter a second gas-liquid separator to be separated, at least one part of the first gas-phase material and all the second gas-phase material obtained through separation are used for steam cracking to generate cracking products including olefin, so that effective subdivision and efficient cracking of different fractions in the heavy hydrocarbon are realized, the heavy hydrocarbon can be flexibly used for direct cracking production of olefin or other products, and the production efficiency is improved. Production devices for pretreatment of heavy hydrocarbon arranged in a traditional oil refining device are greatly reduced, and the energy consumption of olefin production is reduced to the maximum extent in the shortest process.

Description

Technical Field

[0001] The present disclosure relates to the field of petrochemical technology, and in particular, to a method and system for steam cracking heavy hydrocarbons. Background Art

[0002] Compared with traditional cracking raw materials, heavy hydrocarbons (crude oil, etc.) used as steam cracking furnace raw materials have the problems of high final boiling point (greater than 520°C), containing impurities such as colloids and asphaltene, not easy to vaporize, and easy to cause coking. Therefore, corresponding treatment and improvement are needed in the design and production process of cracking furnaces to adapt to the characteristics of heavy hydrocarbons (crude oil, etc.).

[0003] CN111196936A discloses a combined processing method and device for producing olefins by cracking crude oil, which first uses pre-treatment such as desalting and dehydration to remove impurities, then feeds into the ethylene cracking convection section for heating, and feeds the heated feed into the gas-liquid separator to separate the lighter diesel and lighter components into the convection section and the radiation section for steam cracking reaction to produce olefins. The liquid phase from the gas-liquid separator contains components such as atmospheric residue, which are further processed in the hydrogenation unit and then returned to the convection section and the radiation section. This method can use fewer crude oil components.

[0004] CN107001955A discloses a method for thermally cracking crude oil and heavy feed in a pyrolysis reactor to generate olefins. The method describes a solution combining a cracking furnace convection section and a multi-stage (up to 3 stages) separator or a fractionation tower, and the method can perform multiple gas-liquid separations on a mixture of crude oil and steam, and send mixtures of different heavinesses into different radiation section furnace tubes for cracking. The method mentions that when a heavier fraction needs to be gasified, the crude oil is preheated in an external heat exchanger before entering the convection section of the cracking furnace, but the source of heat exchange is not explained. The method uses a multi-stage separator and a fractionation tower to separate the mixture into gas and liquid, and different radiation furnace tubes to crack different fractions. It is only suitable for cracking the separated light components, and cannot meet the requirements of providing raw materials for downstream processing devices.

[0005] CN100564484A discloses a method for cracking heavy hydrocarbon raw materials, wherein the heavy hydrocarbon raw materials mainly include: crude oil, naphtha, gas oil, fuel oil, natural gasoline (condensate oil), residual oil, etc. The method describes a flash vaporization separation process, but it is difficult to separate the gas and liquid components well by simple flash vaporization. It is only suitable for cracking the separated light components, but cannot meet the requirement of providing raw materials for downstream processing devices.

[0006] CN101528894A and CN101778929A introduce the process technology of preparing ethylene by cracking crude oil / condensate. CN101528894A introduces that after crude oil / condensate is preheated in the convection section, the separated light components enter the convection section of the cracking furnace for overheating and then enter the radiation section for cracking, and the heavy components are sent to the atmospheric tower and / or the vacuum tower for further separation. CN101778929A introduces that after the raw materials are mixed with 30% by weight of heavy raw materials such as crude oil or condensate, they enter the upper part of the separation device after being preheated in the convection section to separate the protective naphtha and lighter components, and the separated liquid phase enters the packing tower below for further separation. How to deal with the separated heavy components is not introduced. The evaporation units of these two patents use a stripping tower containing packing or trays, wherein the upper evaporation zone contains a gas-liquid separator to achieve gas-liquid separation.

[0007] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art.

[0008] The methods disclosed in the prior art use a variety of methods to control the flash vaporization rate to be constant, and use special flash evaporation equipment to achieve as much flash evaporation as possible and control the entrainment of heavy components in the gas phase components. However, most of the equipment has relatively high requirements for crude oil when performing primary separation or a complicated flash evaporation process when performing multi-stage separation, and the separated gas phase enters the radiation section for cracking and the separated liquid phase components are further separated, but the separated gas phase components are not used to control the inlet process conditions, vaporization rate and entrainment of light components in the liquid phase components of the secondary gas-liquid separation, and the gas phase components are not sent to other downstream devices for processing to further produce other products. Summary of the invention

[0009] The purpose of the present disclosure is to provide a method and system for steam cracking heavy hydrocarbons, which simplifies the atmospheric and vacuum devices in the traditional methods and systems, is simple to operate, realizes flexible cutting of heavy hydrocarbons, takes into account the raw material supply of ethylene cracking devices and refining-related processing devices such as reforming devices, and has an efficient gas-liquid separation method, which can effectively solve the problem of impurities and light components entrained in the heavy components during the gas-liquid separation process, realizes efficient conversion of heavy hydrocarbons and reduces the energy consumption of the ethylene device.

[0010] A first aspect of the present disclosure provides a method for steam cracking heavy hydrocarbons, the method comprising the following steps:

[0011] S1, allowing the preheated heavy hydrocarbons to enter a first gas-liquid separator for first separation to obtain a first gas phase material and a first liquid phase material;

[0012] S2, mixing at least a portion of the first liquid phase material with a primary dilution steam to obtain a first mixed flow, and subjecting the first mixed flow to a first heating and then mixing it with at least a portion of a secondary dilution steam to obtain a third mixed flow;

[0013] Mixing at least a portion of the first gas phase material with at least a portion of the secondary dilution steam to obtain a second mixed flow, and allowing the second mixed flow to enter a second gas-liquid separator;

[0014] The third mixed flow and the second mixed flow are introduced into the second gas-liquid separator for mixing and then subjected to a second separation to obtain a second gas phase material and a second liquid phase material;

[0015] S3, subjecting the second gaseous material to a second heating and then entering the radiation section of a steam cracking device for steam cracking to obtain a cracking product containing olefins.

[0016] Optionally, step S2 further includes: allowing at least part of the first gas phase material to enter a separation tower for a third separation to obtain a third gas phase material and a third liquid phase material;

[0017] Mixing at least a portion of the third liquid phase material with the secondary dilution steam to obtain a second mixed flow, and allowing the second mixed flow to enter the second gas-liquid separator;

[0018] The third mixed flow and the second mixed flow are subjected to a second separation in a second gas-liquid separator to obtain a second gas phase material and a second liquid phase material.

[0019] Wherein, in step S1, the temperature of the preheated heavy hydrocarbon is 200-400°C, preferably 240-370°C;

[0020] Optionally, the first gas phase material comprises a first light component, and the first liquid phase material comprises a first heavy component;

[0021] Optionally, the gasification rate of the preheated heavy hydrocarbons is 20-65%, preferably 25-45%.

[0022] The method further comprises: in step S2, at least part of the first gas phase material, the first liquid phase material and the primary dilution steam are first mixed to obtain a first mixed flow; the weight ratio of the first liquid phase material to the primary dilution steam is 1:(0.1-0.5), preferably 1:(0.15-0.4);

[0023] The weight ratio of the first liquid phase material to the secondary dilution steam is 1:(0-0.55), preferably 1:(0.10-0.35);

[0024] The weight ratio of the first gas-phase material in the second mixed flow to the first gas-phase material in the first mixed flow is 1:(0.90-153), preferably 1:(2.35-153).

[0025] Optionally, the method further comprises: in step S2, allowing at least a portion of the primary dilution steam to enter a third heating section for heating to obtain superheated primary dilution steam; and performing a first mixing of the superheated primary dilution steam, the first liquid-phase material, and at least a portion of the first gas-phase material to obtain a first mixed flow;

[0026] Allowing at least a portion of the secondary dilution steam to enter a fifth heating section for heating to obtain superheated secondary dilution steam;

[0027] Allowing the first mixed flow to enter a fourth heating section for first heating and then be mixed with at least a portion of the superheated secondary dilution steam to obtain a third mixed flow;

[0028] Optionally, the temperature of the primary dilution steam after superheating is 240-400°C, preferably 280-385°C;

[0029] Optionally, the temperature of the first mixed stream is 200-350°C, preferably 240-300°C;

[0030] Optionally, the temperature of the first mixed stream after the first heating is below 400° C., preferably 285-370° C.;

[0031] Optionally, the temperature of the superheated secondary dilution steam is 400-630°C, preferably 450-595°C.

[0032] Optionally, the weight ratio of the first gas phase material or the third liquid phase material to the secondary dilution steam is 1:(0.2-4); preferably 1:(0.6-3.5).

[0033] Among them, the second gaseous material contains carried steam and a second light component; the second liquid material contains a second heavy component; the final distillation point temperature of the second light component is 330-500°C; the heavy component with a carbon atom number of not less than 30 carried by the second gaseous material is not more than 1wt%, preferably not more than 0.5wt%; the initial distillation point temperature of the second heavy component is not higher than the final distillation point of the second light component, and the flash point temperature of the second liquid material meets the storage requirements.

[0034] Optionally, step S2 also includes:

[0035] Sending at least a portion of the first gaseous material to a post-processing, wherein the post-processing does not include steam cracking;

[0036] The post-treatment includes one or more of reforming treatment, oil product processing treatment of oil refining, and normal isomerization separation;

[0037] Allow at least a portion of the first liquid phase material, at least a portion of the third liquid phase material and the primary dilution steam to enter a first mixer for mixing, superheating or vaporization to obtain a first mixed flow;

[0038] In the first mixed flow, the weight ratio of the first liquid phase material to the primary dilution steam is 1:(0.1-0.5), preferably 1:(0.15-0.4);

[0039] The weight ratio of the third liquid phase material in the second mixed flow to the third liquid phase material in the first mixed flow is 1:(0.90-153), preferably 1:(2.35-153).

[0040] Allowing at least a portion of the secondary dilution steam to enter a third mixer with the first mixed flow for mixing, superheating or vaporization to obtain a third mixed flow;

[0041] Allow at least part of the first gaseous material and the secondary dilution steam to enter the second mixer for mixing, superheating or vaporization to obtain a second mixed flow; or allow at least part of the third liquid material and the secondary dilution steam to enter the second mixer for mixing, superheating or vaporization to obtain a second mixed flow;

[0042] Optionally, the temperature of the second mixed stream is 300-550°C, preferably 325-500°C;

[0043] Optionally, the temperature of the third mixed stream is 200-450°C, preferably 285-400°C.

[0044] Preferably, the third mixed flow and the second mixed flow enter the liquid phase space in the second gas-liquid separator and then undergo a second separation to obtain a second gas phase material and a second liquid phase material;

[0045] Optionally, a cooling aid is introduced above the gas phase space of the second gas-liquid separator to control the gasification rate and the entrainment of heavy components in the gas phase components, and ultimately achieve the purpose of efficient cracking and extended decoking cycle; Optionally, the cooling aid includes water and / or liquid hydrocarbons; or, at least part of the third liquid phase material is introduced above the gas phase space of the second gas-liquid separator as a cooling aid;

[0046] The gas phase component in the second mixed flow performs gas stripping on the liquid phase component in the third mixed flow to control the light component content in the separated second liquid phase material; the liquid phase component obtained by further separation of the second mixed flow is in contact with the third mixed flow in the same layer in the second gas-liquid separator, so as to control the gasification rate and the entrainment of heavy components in the gas phase component;

[0047] Optionally, the weight ratio of the first gas phase material or the third liquid phase material to the secondary dilution steam is 1:(0.2-0.4); preferably 1:(0.6-3.5).

[0048] Optionally, the steam cracking device comprises a convection section and a radiation section; along the height direction of the steam cracking device, the convection section comprises a first heating section, an optional second heating section, a third heating section, a fourth heating section, a fifth heating section and a sixth heating section;

[0049] Optionally, step S1 further includes:

[0050] Allowing the heavy hydrocarbons to be preheated to enter the first heating section for first preheating to obtain first preheated heavy hydrocarbons; then allowing the first preheated heavy hydrocarbons to enter the first gas-liquid separator as the preheated heavy hydrocarbons;

[0051] allowing at least a portion of the first preheated heavy hydrocarbons from the first heating section to enter the second heating section for heating to obtain second preheated heavy hydrocarbons; allowing the second preheated heavy hydrocarbons to enter the first gas-liquid separator as the preheated heavy hydrocarbons;

[0052] Optionally, the first preheated heavy hydrocarbon is subjected to a desalination treatment before being heated, or the heavy hydrocarbon to be preheated is subjected to a desalination treatment before being subjected to the first preheating.

[0053] Another aspect of the present disclosure provides a system for steam cracking heavy hydrocarbons, the system comprising a steam cracking device, a first gas-liquid separator and a second gas-liquid separator; the steam cracking device comprises a convection section and a radiation section;

[0054] The first gas-liquid separator is configured to allow the preheated heavy hydrocarbons to enter therein for first separation to obtain a first gas phase material and a first liquid phase material;

[0055] The second gas-liquid separator is configured to allow the third mixed flow and the second mixed flow to enter therein for second separation to obtain a second gas phase material and a second liquid phase material;

[0056] The radiant section of the steam cracking device is configured to steam crack at least a portion of the second gas phase material to obtain a cracking product containing olefins;

[0057] The system further comprises a post-processing device, which is configured to perform post-processing on at least a portion of the first gas-phase material being sent out.

[0058] The convection section is provided with a raw material heating inlet and a raw material heating outlet; the radiation section is provided with a steam cracking inlet and a cracking product outlet;

[0059] The first gas-liquid separator is provided with a gas-liquid separation inlet, a first gas-phase material outlet and a first liquid-phase material outlet; the gas-liquid separation inlet of the first gas-liquid separator is connected to the raw material heating outlet of the convection section; the first liquid-phase material outlet of the first gas-liquid separator is connected to the steam cracking inlet of the radiation section;

[0060] The second gas-liquid separator is provided with a third mixed stream inlet, an optional cooling aid inlet, a second mixed stream inlet, a second gas phase material outlet and a second liquid phase material outlet;

[0061] The cooling aid inlet includes a liquid hydrocarbon inlet and / or a water inlet;

[0062] Wherein, the third mixed flow inlet of the second gas-liquid separator is connected to the heating outlet of the fourth heating section; optionally, the first gas-phase material outlet of the first gas-liquid separator is connected to the second mixed flow inlet of the second gas-liquid separator via a second pipeline;

[0063] The radiation section comprises a steam cracking inlet and a cracking product outlet; the outlet of the second gas phase material of the second gas-liquid separator is connected to the steam cracking inlet of the radiation section.

[0064] Wherein, along the height direction of the steam cracking device, the convection section includes a first heating section, an optional second heating section, a third heating section, a fourth heating section, a fifth heating section and a sixth heating section;

[0065] Wherein, the heating inlet of the first heating section is used to introduce the heavy hydrocarbons to be preheated; the heating outlet of the first heating section is connected to the gas-liquid separation inlet of the first gas-liquid separator; preferably, a pressure regulating valve is provided on the inlet pipeline of the gas-liquid separation inlet of the first gas-liquid separator to control the preheating temperature of the heavy hydrocarbons entering the first gas-liquid separator; optionally, a pressure regulating valve is provided on the outlet pipeline of the first gas-phase material outlet to further control the gasification rate;

[0066] The heating inlet of the fourth heating section is connected to the first liquid phase material outlet of the first gas-liquid separator via a first pipeline; the heating inlet of the third heating section is connected to a primary steam source; the heating outlet of the third heating section is connected to the first pipeline;

[0067] The heating outlet of the fourth heating section is connected to the third mixed flow inlet of the second gas-liquid separator; the heating inlet of the fifth heating section is connected to the secondary steam source; the heating outlet of the fifth heating section is connected to the connecting pipeline between the heating outlet of the fourth heating section and the third mixed flow inlet of the second gas-liquid separator and the second pipeline respectively;

[0068] The heating inlet of the sixth heating section is communicated with the second gas-phase material outlet of the second gas-liquid separator; the heating outlet of the sixth heating section is communicated with the steam cracking inlet of the radiation section;

[0069] Optionally, the second liquid phase material outlet of the second gas-liquid separator can be used to communicate with a hydrocracking or catalytic cracking unit;

[0070] Optionally, a tower tray, a cooler and a cyclone separator or a combination of at least two of them are arranged inside the second gas-liquid separator.

[0071] Optionally, the system further comprises a separation tower; the separation tower is provided with a first gas phase material inlet, a third gas phase material outlet and a third liquid phase material outlet;

[0072] The first gas-phase material outlet of the first gas-liquid separator is connected to the first gas-phase material inlet of the separation tower, and the third liquid-phase material outlet of the separation tower is connected to the second mixed flow inlet of the second gas-liquid separator via a third pipeline; the heating outlet of the fifth heating section is connected to the third pipeline;

[0073] The third gas phase material outlet of the separation tower is communicated with a post-processing device.

[0074] Optionally, the first pipeline is further provided with a first mixer for mixing the first liquid-phase material and the primary dilution steam therein to be superheated or vaporized to obtain a first mixed flow;

[0075] The second pipeline is also provided with a second mixer for mixing the first gaseous material and the secondary dilution steam therein to be superheated or gasified to obtain a second mixed flow;

[0076] Optionally, a third mixer is further provided on the connecting pipeline between the heating outlet of the fourth heating section and the third mixed flow inlet of the second gas-liquid separator, for mixing the first mixed flow with at least part of the secondary dilution steam to be superheated or vaporized to obtain a third mixed flow;

[0077] The first mixer is provided with a first liquid material inlet, a primary dilution steam inlet and a first mixed flow outlet; the first liquid material outlet of the first gas-liquid separator is connected to the first liquid material inlet of the first mixer; the heating outlet of the third heating section is connected to the primary dilution steam inlet of the first mixer; the first mixed flow outlet of the first mixer is connected to the heating inlet of the fourth heating section;

[0078] The second mixer is provided with a first gas-phase material inlet, a secondary dilution steam inlet, and a second mixed flow outlet; the first gas-phase material inlet of the second mixer is connected to the first gas-phase material outlet of the first gas-liquid separator, and the second mixed flow outlet of the second mixer is connected to the second mixed flow inlet of the second gas-liquid separator;

[0079] The third mixer is provided with a first mixed flow inlet, a secondary dilution steam inlet and a third mixed flow outlet; the heating outlet of the fourth heating section is connected to the first mixed flow inlet of the third mixer, the heating outlet of the fifth heating section is connected to the secondary dilution steam inlet of the second mixer and the secondary dilution steam inlet of the third mixer respectively, and the third mixed flow outlet of the third mixer is connected to the third mixed flow inlet of the second gas-liquid separator;

[0080] Optionally, the outlet of the first gas-phase material is connected to the first gas-phase material inlet of the first pipeline and the second mixer respectively;

[0081] Alternatively, the second mixer is disposed on the third pipeline, and is used to allow the third liquid phase material and the secondary dilution steam to enter therein for mixing, overheating or vaporization to obtain a second mixed flow; the second mixer is provided with a third liquid phase material inlet, a secondary dilution steam inlet, and a second mixed flow outlet;

[0082] The third liquid material outlet of the separation tower is connected to the third liquid material inlet of the second mixer; the heating outlet of the fifth heating section is respectively connected to the secondary dilution steam inlet of the second mixer and the secondary dilution steam inlet of the third mixer; the second mixed flow outlet of the second mixer is connected to the second mixed flow inlet of the second gas-liquid separator.

[0083] Optionally, the heating outlet of the first heating section is communicated with the heating inlet of the second heating section; the heating outlet of the second heating section is communicated with the gas-liquid separation inlet of the first gas-liquid separator;

[0084] Optionally, the outlet of the third liquid-phase material is connected to the first pipeline and the third liquid-phase material inlet of the second mixer, respectively.

[0085] Through the above technical scheme, the present disclosure provides a method and system for steam cracking heavy hydrocarbons, and the beneficial effects include at least: (1) a first gas-liquid separator is set to perform preliminary separation of heavy hydrocarbons, which can reduce the size of the next-stage separation device and thus reduce the energy consumed by separation when part of the first gas phase material is further separated. At the same time, part of the first gas phase material can be selectively not separated and enter the next-stage separation device as a stripping agent to control the light component content and flash point in the liquid phase component in the device; the cooling aid is in contact with the third mixed flow and the second mixed flow in the second gas-liquid separator at the same layer, or is mixed or countercurrently contacted with the separated gas phase components, so as to control the gasification rate and the entrainment of heavy components in the gas phase components, and finally achieve the purpose of efficient cracking and extending the decoking cycle; (2) a two-stage separation is set, which has a wide range of adaptability to heavy hydrocarbons, can be cut into at least three different narrow distillation range components according to the properties of different distillation range components of heavy hydrocarbons, and improve its separation effect, so as to achieve efficient cracking of heavy hydrocarbons, high olefin yield and maximum application of existing steam cracking technology. The technology is mature and the operation is simple; (3) the first gas phase material in the second mixed flow is used as a stripping agent to countercurrently contact with the liquid phase material obtained after the third mixed flow enters the second gas-liquid separator, which can effectively control the content of the gas phase component entrained in the second liquid phase component, so that the light components of the heavy hydrocarbons can be fully utilized, thereby improving the utilization rate and olefin yield; (4) the temperature of the second mixed flow is controlled below 550°C, thereby avoiding the liquid phase material in the second gas-liquid separator from cracking and producing coking products after contacting at too high a temperature, and entraining to the radiation section to cause coking in the radiation section; on the other hand, it can reduce the requirements for the material of the gas-liquid separation device, thereby reducing the production cost; and it can introduce as much light component in the first liquid phase material as possible into the first gas phase material to improve the utilization rate of wide-fraction hydrocarbons; (5) it provides raw materials for downstream devices, flexibly sets downstream separation devices and performs appropriate cutting to achieve "olefins when suitable, aromatics when suitable, and oil when suitable", and achieves quality improvement and efficiency enhancement with existing refining and chemical integration devices, and can also be used for the production of olefins in new refining and chemical integration devices.

[0086] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0088] Figure 1 The present invention provides an exemplary flow chart of steam cracking of heavy hydrocarbons to produce olefins.

[0089] Figure 2The present invention provides an exemplary flow chart of steam cracking of heavy hydrocarbons to produce olefins.

[0090] Figure 3 The present invention provides an exemplary flow chart of steam cracking of heavy hydrocarbons to produce olefins.

[0091] Description of Reference Numerals

[0092] 1A-first heating section; BFW-boiler feed water preheating section; 1B-second heating section; 3A-third heating section; 4-fourth heating section; 3B-fifth heating section; 5-sixth heating section; 6A-first mixer; 6B-second mixer; 6C-third mixer; 7-separation tower; 8-first gas-liquid separator; 9-second gas-liquid separator. DETAILED DESCRIPTION

[0093] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0094] In the present disclosure, unless otherwise stated, the words "first", "second", "third", etc. are used only to distinguish different components and do not have actual meanings such as the order of connection between the front and the back. In the present disclosure, the directional words used, such as "upper, lower, top, bottom", generally refer to the upper and lower, top and bottom of the device in normal use.

[0095] In the present disclosure, the terms "primary dilution steam", "secondary dilution steam" and the like are used only to distinguish the steam introduced in different steps, but do not contain any actual meaning such as the properties of the steam itself.

[0096] Each device used in the present disclosure is a structure conventionally selected in the art.

[0097] A first aspect of the present disclosure provides a method for steam cracking heavy hydrocarbons, the method comprising the following steps:

[0098] S1, allowing the preheated heavy hydrocarbons to enter the first gas-liquid separator 8 for first separation to obtain a first gas phase material and a first liquid phase material;

[0099] S2, mixing at least a portion of the first liquid phase material with a primary dilution steam to obtain a first mixed flow, and subjecting the first mixed flow to a first heating and then mixing it with at least a portion of a secondary dilution steam to obtain a third mixed flow;

[0100] Mixing at least a portion of the first gas phase material with at least a portion of the secondary dilution steam to obtain a second mixed stream;

[0101] The third mixed flow and the second mixed flow enter into a second gas-liquid separator 9 for second separation to obtain a second gas phase material and a second liquid phase material;

[0102] S3, subjecting the second gaseous material to a second heating and then entering the radiation section of a steam cracking device for steam cracking to obtain a cracking product containing olefins.

[0103] The heavy hydrocarbon feedstock used in the present disclosure includes one or more of the following feedstocks: paraffin-based crude oil, intermediate-based crude oil, cycloalkane-based crude oil, condensate oil, gasoline, kerosene, diesel, tail oil, fuel oil, reformed oil, etc. processed by refineries such as atmospheric and vacuum distillation, reforming, catalysis, coking, etc.

[0104] After extensive research, the inventors of the present disclosure have found that heavy hydrocarbons (including crude oil, etc.) have complex characteristics (for example, they contain impurities such as fractions with high terminal distillation points, colloids and asphaltene, etc.), and are difficult to vaporize and easily cause coking during direct cracking. It is necessary to make corresponding treatments and improvements in the design of the cracking furnace and the production process to adapt to the characteristics of the heavy hydrocarbons themselves. Optionally, it is necessary to remove 10-30% by weight of heavy fractions (different heavy hydrocarbons have different contents) in the heavy hydrocarbons that are not suitable for cracking, and one of the effective removal methods is to perform gas-liquid separation on the heavy hydrocarbons. The present disclosure further preheats the heavy hydrocarbons before performing gas-liquid separation, controls the preheating temperature and gasification rate in the convection section of the cracking furnace, and further controls the tube wall temperature of the convection section to prevent the tube wall temperature and gasification rate from being too high, resulting in carbonization and coking of heavier components in the ungasified heavy hydrocarbons.

[0105] The present disclosure provides a process and system for steam cracking heavy hydrocarbons to produce olefins, wherein the preheated heavy hydrocarbons are first separated in a first gas-liquid separator 8, and the separated first liquid phase material and the first gas phase material are respectively mixed with dilution steam and sent to a second gas-liquid separator 9 for second separation, and the second gas phase material obtained by the second separation is heated and sent to the radiation section of the steam cracking device for steam cracking, thereby achieving subdivision of components in different distillation ranges, having a wide range of applicability to heavy hydrocarbons, and the separated fractions can be flexibly utilized, thereby maximizing the application of existing steam cracking technology.

[0106] The present invention cuts / separates heavy hydrocarbons into fractions or gasification rates according to the properties of heavy hydrocarbons and other cracking furnace steam cracking raw materials or the properties of oil products of downstream refining units (such as reforming, etc.); part of the first gas phase material is sent out for post-processing, and multiple fractions can be flexibly separated according to needs, thereby achieving quality improvement and efficiency enhancement with existing integrated refining and chemical units.

[0107] The post-treatment described in the present disclosure is reforming, oil product processing of oil refining, normal isomer separation and other treatment methods not including steam cracking, which can effectively separate heavy hydrocarbons with high aromatic content. Among them, heavy hydrocarbons include mixed hydrocarbons with a wide range, whose final boiling point is above 540°C, for example, heavy hydrocarbons with an initial boiling point temperature of 15°C and a final boiling point temperature of above 750°C, or a hydrocarbon mixture containing components that are easy to coke under the operating conditions of a cracking furnace.

[0108] The radiation section furnace tube of the present invention is also provided with a twisted sheet enhanced heat transfer element or other coking inhibition elements to prevent the second gas phase material from carrying excessive heavy components with carbon atoms of 30 or more.

[0109] In one embodiment, the method provided in the present disclosure also includes introducing a cooling aid into the second gas-liquid separator 9, wherein the cooling aid is selected from one or both of liquid hydrocarbons and / or water; preferably, the cooling aid is introduced into the gas phase space of the second gas-liquid separator 9 above the first mixed flow to cool the gas phase component in the first mixed flow.

[0110] In the present disclosure, at least part of the first gas phase material and / or cooling aid is introduced into the gas phase space of the second gas-liquid separator 9 and contacts with the second gas phase material therein. When the temperature is higher than a certain range and the gasification rate reaches a certain value, at least part of the first gas phase material is used as reflux or washing for gas-liquid separation, which can effectively prevent the entrainment of heavy fractions and avoid impurities from entering the radiation section to cause coking of furnace tubes and the like; the impurities include one or more of colloids, asphaltene, metal impurities, sulfur, oxygen, nitrogen and heavy components.

[0111] In one embodiment, step S2 further includes: allowing at least part of the first gas phase material to enter a separation tower 7 for a third separation to obtain a third gas phase material and a third liquid phase material;

[0112] Mixing at least a portion of the third liquid phase material with the secondary dilution steam to obtain a second mixed flow, and allowing the second mixed flow to enter the second gas-liquid separator 9;

[0113] The third mixed flow and the second mixed flow are subjected to a second separation in the second gas-liquid separator 9 to obtain a second gas phase material and a second liquid phase material.

[0114] In one embodiment, part of the third liquid phase material can also be used as a cooling aid to enter the second gas-liquid separator 9 to further adjust the reaction temperature in the second gas-liquid separator 9 .

[0115] In a preferred embodiment, the weight ratio of the second gas phase material to the at least part of the first gas phase material is 1:(0.01-0.2), preferably 1:(0.05-0.15).

[0116] In a preferred embodiment, the weight ratio of the second gaseous material to the water is 1:(0.01-0.2), preferably 1:(0.05-0.15); or, the weight ratio of the second gaseous material to the liquid hydrocarbon is 1:(0.01-0.2), preferably 1:(0.05-0.15).

[0117] In a preferred embodiment, the method further includes: the cooling aid introduction method is selected from at least one of the following methods: along the axial direction of the second gas-liquid separator 9, the water introduction position is above the liquid hydrocarbon introduction position; or along the axial direction of the second gas-liquid separator 9, the water introduction position is below the liquid hydrocarbon introduction position; or along the axial direction of the second gas-liquid separator 9, the water introduction position and the liquid hydrocarbon introduction position are located in the same plane.

[0118] In one embodiment, in step S1, the temperature of the preheated heavy hydrocarbon is 200-400°C, preferably 240-370°C;

[0119] The first gas phase material contains a first light component, and the first liquid phase material contains a first heavy component; the gasification rate of the preheated heavy hydrocarbons is 20-65%, preferably 25-45%.

[0120] In the present disclosure, heavy hydrocarbons are preheated and their preheating temperature and gasification rate in the convection section of the steam cracking device are controlled, thereby controlling the tube wall temperature of the convection section.

[0121] In a preferred embodiment, step S1 further comprises: allowing the heavy hydrocarbons to be preheated to enter the first heating section 1A for first preheating to obtain first preheated heavy hydrocarbons; and then allowing the first preheated heavy hydrocarbons to enter the first gas-liquid separator 8 as the preheated heavy hydrocarbons;

[0122] In a preferred embodiment, at least part of the first preheated heavy hydrocarbons from the first heating section 1A enter the second heating section 1B for heating to obtain second preheated heavy hydrocarbons, and the second preheated heavy hydrocarbons enter the first gas-liquid separator 8 as the preheated heavy hydrocarbons; specifically, the heavy hydrocarbon preheating method can be selected according to the actual heat required by the steam cracking system.

[0123] In a preferred embodiment, step S1 further includes: subjecting the first preheated heavy hydrocarbon to desalination treatment and then heating it, and the flue gas obtained by the desalination pretreatment can further heat the first preheated heavy hydrocarbon; or, subjecting the heavy hydrocarbon to be preheated to desalination treatment and then entering the first heating section 1A for the first preheating. The present disclosure couples the steam cracking device with the electric desalination device, which is beneficial to the comprehensive utilization of energy, reduces energy consumption and increases the applicability to heavy hydrocarbons.

[0124] In one embodiment, optionally, the method further comprises: in step S2, first mixing at least part of the first gas-phase material and the first liquid-phase material with the primary dilution steam to obtain a first mixed flow;

[0125] The weight ratio of the first liquid phase material to the primary dilution steam is 1:(0.1-0.5), preferably 1:(0.15-0.4);

[0126] In step S2, the weight ratio of the first liquid phase material to the primary dilution steam is 1:(0.1-0.5), preferably 1:(0.15-0.4);

[0127] The weight ratio of the first gas phase material to the secondary dilution steam is 1:(0-0.55), preferably 1:(0.10-0.35).

[0128] In a preferred embodiment, the method further comprises: in step S2, allowing at least a portion of the primary dilution steam to enter the third heating section 3A for heating to obtain superheated primary dilution steam, and performing a first mixing of the superheated primary dilution steam, the first liquid-phase material and at least a portion of the first gas-phase material to obtain a first mixed flow;

[0129] Optionally, a weight ratio of the first gas-phase material in the second mixed flow to the first gas-phase material in the first mixed flow is 1:(0.90-153), preferably 1:(2.35-153).

[0130] Allowing at least a portion of the secondary dilution steam to enter the fifth heating section 3B for heating to obtain superheated secondary dilution steam;

[0131] The first mixed flow enters the fourth heating section 4 for first heating and is then mixed with at least a portion of the superheated secondary dilution steam to obtain a third mixed flow;

[0132] The temperature of the superheated primary dilution steam is 240-400°C, preferably 280-385°C;

[0133] The temperature of the first mixed stream is 200-350°C, preferably 240-300°C.

[0134] In one embodiment, the temperature of the first mixed stream after the first heating is below 400°C, preferably 285-370°C;

[0135] The temperature of the superheated secondary dilution steam is 400-630°C, preferably 450-595°C;

[0136] Optionally, the temperature of the third mixed stream is 200-450°C, preferably 285-400°C.

[0137] In one implementation, step S2 further includes:

[0138] Allow at least part of the first liquid phase material, at least part of the third liquid phase material and the primary dilution steam to enter the first mixer 6A for mixing, superheating or vaporization to obtain a first mixed flow; allow at least part of the secondary dilution steam and the first mixed flow to enter the third mixer 6C for mixing, superheating or vaporization to obtain a third mixed flow;

[0139] Allow at least part of the first gaseous material and the secondary dilution steam to enter the second mixer 6B for mixing, superheating or gasification to obtain a second mixed flow;

[0140] Optionally, a weight ratio of the third liquid phase material in the second mixed flow to the third liquid phase material in the first mixed flow is 1:(2-154), preferably 1:(3.5-153).

[0141] Optionally, the present invention introduces at least a portion of the first gas phase material or the third liquid phase material into the first mixer 6A to mix with the first liquid phase material and the primary dilution steam as a first mixed flow, which is used to control the temperature of the first mixed flow, and then control the gasification rate and the content of the heavy components to prevent coking in the convection section, and can flexibly adapt to various heavy hydrocarbon feedstocks.

[0142] Alternatively, at least part of the third liquid phase material and the secondary dilution steam are allowed to enter the second mixer 6B to be mixed, overheated or vaporized to obtain a second mixed flow;

[0143] Introducing the second mixed flow into the liquid phase space or above the liquid surface of the second gas-liquid separator 9, so that the third mixed flow and the second mixed flow are subjected to a second separation in the second gas-liquid separator 9 to obtain a second gas phase material and a second liquid phase material;

[0144] Optionally, the temperature of the second mixed stream is 300-550°C, preferably 325-500°C;

[0145] In the present disclosure, at least a portion of the first gas phase material is mixed with secondary steam to obtain a second mixed flow as a stripping agent, and the temperature of the second mixed flow is controlled to be lower than 550° C. to prevent the heavy components in the third mixed material from coking due to contact with high-temperature gas during the stripping process, and to reduce the material grade of the second gas-liquid separator to reduce investment.

[0146] Optionally, the weight ratio of the first gas phase material or the third liquid phase material to the secondary dilution steam is 1:(0.2-4); preferably 1:(0.6-3.5).

[0147] Optionally, the method further comprises: sending at least a portion of the first gaseous material for post-processing, wherein the post-processing comprises one or more of reforming, oil product processing of oil refining, and normal isomer separation, but does not comprise steam cracking.

[0148] In one embodiment, the first gas-phase material comprises a third light component, a first middle distillate, and a third heavy component;

[0149] In one embodiment, the second gas phase material comprises entrained steam and a second light component; the second liquid phase material comprises a second heavy component;

[0150] In a preferred embodiment, the third gas phase material comprises entrained steam and a third light component; and the third liquid phase material comprises a third heavy component.

[0151] In one embodiment, the first light component accounts for 30-40% by weight of the total weight of heavy hydrocarbons, the first light component has an initial distillation point temperature of ≤270°C and a final distillation point temperature of 265-275°C; the first heavy component is in equilibrium with the first light component; the final distillation point temperature of the second light component is 330-500°C; the second gaseous material carries a heavy component with a carbon atom number of not less than 30 and is not more than 1wt%, preferably not more than 0.5wt%; the second heavy component is in equilibrium with the second light component; the third light component mainly includes C1-C6 components, has a final distillation point temperature of ≤90°C, and is sent to other cracking furnaces for cracking; the first intermediate distillate mainly includes C6-C 10 The third heavy component has a distillation range of 180-380°C and mainly includes C 11 And above components, return to this cracking furnace for cracking. It should be understood that the initial distillation point or final distillation point of each fraction in the present disclosure is a range value, and in actual operation it can be any temperature within the range value. And the present disclosure can select the separated fractions according to actual production needs. The first intermediate component of the present disclosure has a high aromatic content and is not suitable for steam cracking. It can be flexibly sent to reforming and other oil refining units as raw materials, so that aromatics can be used, olefins can be used, and oils can be used.

[0152] The above operating temperatures are all temperatures under normal operating conditions under conventional operating conditions of the cracking furnace.

[0153] The parameters in each step involved in the present disclosure and the control methods and technical principles of the parameters have been described in detail in the foregoing content and will not be repeated here.

[0154] Another aspect of the present disclosure provides a system for steam cracking heavy hydrocarbons, the system comprising a steam cracking device, a first gas-liquid separator 8 and a second gas-liquid separator 9; the steam cracking device comprises a convection section and a radiation section;

[0155] The first gas-liquid separator 8 is configured to allow the preheated heavy hydrocarbons to enter therein for first separation to obtain a first gas phase material and a first liquid phase material;

[0156] The second gas-liquid separator 9 is configured to allow the third mixed flow and the second mixed flow to enter therein for second separation to obtain a second gas phase material and a second liquid phase material;

[0157] The radiant section of the steam cracking device is configured to steam crack at least a portion of the second gas phase material to obtain a cracking product containing olefins;

[0158] The system further includes a post-processing device, which is configured to post-process at least a portion of the first gas-phase material sent out, and the post-processing device does not include a steam cracking device.

[0159] The convection section is provided with a raw material heating inlet and a raw material heating outlet; the radiation section is provided with a steam cracking inlet and a cracking product outlet;

[0160] The first gas-liquid separator 8 is provided with a gas-liquid separation inlet, a first gas-phase material outlet and a first liquid-phase material outlet; the gas-liquid separation inlet of the first gas-liquid separator 8 is connected to the raw material heating outlet of the convection section; the first liquid-phase material outlet of the first gas-liquid separator 8 is connected to the steam cracking inlet of the radiation section;

[0161] The second gas-liquid separator 9 is provided with a third mixed stream inlet, an optional cooling aid inlet, a second mixed stream inlet, a second gas phase material outlet and a second liquid phase material outlet;

[0162] The cooling aid inlet includes a liquid hydrocarbon inlet and / or a water inlet;

[0163] The third mixed flow inlet of the second gas-liquid separator 9 is connected to the heating outlet of the fourth heating section 4; optionally, the first gas-phase material outlet of the first gas-liquid separator 8 is connected to the second mixed flow inlet of the second gas-liquid separator 9 via a second pipeline;

[0164] The radiation section includes a steam cracking inlet and a cracking product outlet; the outlet of the second gas phase material of the second gas-liquid separator 9 is connected to the steam cracking inlet of the radiation section.

[0165] Wherein, along the height direction of the steam cracking device, the convection section includes a first heating section 1A, an optional second heating section 1B, a third heating section 3A, a fourth heating section 4, a fifth heating section 3B and a sixth heating section 5;

[0166] Wherein, the heating inlet of the first heating section 1A is used to introduce the heavy hydrocarbons to be preheated; the heating outlet of the first heating section 1A is connected to the gas-liquid separation inlet of the first gas-liquid separator 8; preferably, a pressure regulating valve is provided on the inlet pipeline of the gas-liquid separation inlet of the first gas-liquid separator 8 to control the preheating temperature of the heavy hydrocarbons entering the first gas-liquid separator 8; optionally, a pressure regulating valve is provided on the outlet pipeline of the first gas-phase material outlet to further control the gasification rate;

[0167] The heating inlet of the fourth heating section 4 is connected to the first liquid material outlet of the first gas-liquid separator 8 via a first pipeline; the heating inlet of the third heating section 3A is connected to a primary steam source; the heating outlet of the third heating section 3A is connected to the first pipeline;

[0168] The heating outlet of the fourth heating section 4 is connected to the third mixed flow inlet of the second gas-liquid separator 9; the heating inlet of the fifth heating section 3B is connected to the secondary steam source; the heating outlet of the fifth heating section 3B is connected to the connecting pipeline between the heating outlet of the fourth heating section 4 and the third mixed flow inlet of the second gas-liquid separator 9 and the second pipeline respectively;

[0169] The heating inlet of the sixth heating section 5 is connected to the second gas phase material outlet of the second gas-liquid separator 9; the heating outlet of the sixth heating section 5 is connected to the steam cracking inlet of the radiation section;

[0170] Optionally, the second liquid phase material outlet of the second gas-liquid separator 9 can be used to communicate with a hydrocracking or catalytic cracking unit;

[0171] Optionally, at least one of a cooler, a tower tray and a hydrocyclone is disposed inside the second gas-liquid separator 9 .

[0172] Optionally, the system further comprises a separation tower 7; the separation tower 7 is provided with a first gas phase material inlet, a third gas phase material outlet and a third liquid phase material outlet;

[0173] The first gas-phase material outlet of the first gas-liquid separator 8 is connected to the first gas-phase material inlet of the separation tower 7, and the third liquid-phase material outlet of the separation tower 7 is connected to the second mixed flow inlet of the second gas-liquid separator 9 via a third pipeline; the heating outlet of the fifth heating section 3B is connected to the third pipeline;

[0174] The third gas phase material outlet of the separation tower 7 is communicated with a post-processing device.

[0175] Optionally, the first pipeline is further provided with a first mixer 6A for mixing the first liquid-phase material and the primary dilution steam therein to superheat or vaporize the mixture to obtain a first mixed flow;

[0176] Optionally, the second pipeline is further provided with a second mixer 6B for mixing the first gaseous material and the secondary dilution steam therein to superheat or gasify them to obtain a second mixed flow;

[0177] Optionally, a third mixer 6C is provided on the connecting pipeline between the heating outlet of the fourth heating section 4 and the third mixed flow inlet of the second gas-liquid separator 9, for mixing the first mixed flow with at least part of the secondary dilution steam to be superheated or vaporized to obtain a third mixed flow;

[0178] The first mixer 6A is provided with a first liquid material inlet, a primary dilution steam inlet and a first mixed flow outlet; the first liquid material outlet of the first gas-liquid separator 8 is connected to the first liquid material inlet of the first mixer 6A; the heating outlet of the third heating section 3A is connected to the primary dilution steam inlet of the first mixer 6A, and the first mixed flow outlet of the first mixer 6A is connected to the heating inlet of the fourth heating section 4;

[0179] The second mixer 6B is provided with a first gas-phase material inlet, a secondary dilution steam inlet, and a second mixed flow outlet; the first gas-phase material outlet of the first gas-liquid separator 8 is connected to the first gas-phase material inlet of the second mixer 6B; the second mixed flow outlet of the second mixer 6B is connected to the second mixed flow inlet of the second gas-liquid separator 9;

[0180] The third mixer 6C is provided with a first mixed flow inlet, a secondary dilution steam inlet and a third mixed flow outlet; the heating outlet of the fourth heating section 4 is connected to the first mixed flow inlet of the third mixer 6C, the heating outlet of the fifth heating section 3B is respectively connected to the secondary dilution steam inlet of the second mixer 6B and the secondary dilution steam inlet of the third mixer 6C, and the third mixed flow outlet of the third mixer 6C is connected to the third mixed flow inlet of the second gas-liquid separator 9; optionally, the outlet of the first gas-phase material is respectively connected to the first pipeline and the first gas-phase material inlet of the second mixer 6B;

[0181] Alternatively, the second mixer 6B is disposed on the third pipeline, and is used to mix the third liquid phase mixed material and the secondary dilution steam therein, and superheat or vaporize them to obtain a second mixed flow;

[0182] The second mixer 6B is provided with a third liquid material inlet, a secondary dilution steam inlet and a second mixed flow outlet; the third liquid material outlet of the separation tower 7 is connected to the third liquid material inlet of the second mixer 6B; the heating outlet of the fifth heating section 3B is respectively connected to the secondary dilution steam inlets of the second mixer 6B and the second mixer 6C; the second mixed flow outlet of the second mixer 6B is connected to the second mixed flow inlet of the second gas-liquid separator 9;

[0183] Optionally, the heating outlet of the first heating section 1A is connected to the heating inlet of the second heating section 1B; the heating outlet of the second heating section 1B is connected to the gas-liquid separation inlet of the first gas-liquid separator 8; optionally, the outlet of the third liquid phase material is respectively connected to the first pipeline and the third liquid phase material inlet of the second mixer 6B.

[0184] like Figure 1 As shown, in an exemplary embodiment of the system for producing olefins by steam cracking heavy hydrocarbons provided by the present disclosure, the system comprises: a steam cracking device, a first mixer 6A, a second mixer 6B, a third mixer 6C, a separation tower 7, a first gas-liquid separator 8 and a second gas-liquid separator 9;

[0185] The steam cracking device includes a convection section and a radiation section; along the height direction of the steam cracking device, the convection section is provided with a first heating section 1A, a second heating section 1B, a boiler feed water preheating section BFW, a third heating section 3A, a fourth heating section 4, a fifth heating section 3B and a sixth heating section 5 from top to bottom; the radiation section includes a steam cracking inlet and a cracking product outlet;

[0186] The heating inlet of the first heating section 1A is used to introduce the heavy hydrocarbons to be preheated; the heating outlet of the first heating section 1A is connected to the heating inlet of the second heating section 1B, and the heating outlet of the second heating section 1B is connected to the gas-liquid separation inlet of the first gas-liquid separator 8;

[0187] The first liquid phase material outlet of the first gas-liquid separator 8 is connected to the heating inlet of the fourth heating section 4 via the first pipeline, and the first mixer 6A is arranged on the first pipeline; the heating inlet of the third heating section 3A is connected to the primary steam source, the heating outlet of the third heating section 3A is connected to the primary dilution steam inlet of the first mixer 6A, and the first mixed flow outlet of the first mixer 6A is connected to the heating inlet of the fourth heating section 4; the heating outlet of the fourth heating section 4 is connected to the third mixed flow inlet of the second gas-liquid separator 9, and the third mixer 6C is arranged on the connecting pipeline; the heating inlet of the fifth heating section 3B is connected to the secondary steam source;

[0188] The first gas-phase material outlet of the first gas-liquid separator 8 is connected to the first gas-phase material inlet of the separation tower 7, the third liquid-phase material outlet of the separation tower 7 is connected to the second mixed flow inlet of the second gas-liquid separator 9 via a third pipeline, a second mixer 6B is provided on the third pipeline, the third liquid-phase material outlet of the separation tower 7 is connected to the third liquid-phase material inlet of the second mixer 6B, and the third gas-phase material outlet of the separation tower 7 is connected to the post-processing device; the heating outlet of the fifth heating section 3B is respectively connected to the secondary dilution steam inlet of the third mixer 6C and the secondary dilution steam inlet of the second mixer 6B on the third pipeline, the second mixed flow outlet of the second mixer 6B is connected to the second mixed flow inlet of the second gas-liquid separator 9; the second gas-liquid separator 9 is also provided with a cooling agent inlet;

[0189] use Figure 1 The specific process flow of the system shown in the figure for producing olefins by steam cracking heavy hydrocarbons includes:

[0190] S1, allowing the heavy hydrocarbons to be preheated to enter the first heating section 1A for heating to obtain preheated heavy hydrocarbons; allowing the preheated heavy hydrocarbons to enter the second heating section 1B for first heating to obtain second preheated heavy hydrocarbons, and allowing the second preheated heavy hydrocarbons to enter the first gas-liquid separator 8 as the preheated heavy hydrocarbons for first separation to obtain a first gas phase material and a first liquid phase material;

[0191] S2, mixing at least part of the first liquid phase material with the primary dilution steam that has been superheated in the third heating section 3A in the first mixer 6A to be superheated or vaporized to obtain a first mixed flow, allowing the first mixed flow to enter the fourth heating section 4 for first heating and then to be mixed with at least part of the secondary dilution steam in the third mixer 6C to be superheated or vaporized to obtain a third mixed flow, and allowing the third mixed flow to enter the second gas-liquid separator 9;

[0192] Allow at least part of the first gas phase material to enter the separation tower 7 for third separation to obtain a third gas phase material and a third liquid phase material; allow the third gas phase material to enter a post-processing device;

[0193] The third liquid phase material is mixed with the secondary dilution steam superheated in the fifth heating section 3B and superheated or vaporized in the second mixer 6B to obtain a second mixed flow;

[0194] The second mixed flow enters the second gas-liquid separator 9 to contact with the third mixed flow for second separation, thereby obtaining a second gas phase material and a second liquid phase material; at the same time, a cooling agent is introduced into the gas phase space of the second gas-liquid separator 9 to control the inner wall temperature of the tube of the second gas-liquid separator 9 to prevent coking during the regasification process; the cooling agent is cooling water;

[0195] S3, allowing the second gas-phase material to enter the sixth heating section 5 for a second heating and then enter the radiation section of the steam cracking device for steam cracking to obtain a cracking product containing olefins; allowing the second liquid-phase material to enter a post-processing device.

[0196] like Figure 2 As shown, in an exemplary embodiment of the system for producing olefins by steam cracking heavy hydrocarbons provided by the present disclosure, the system is Figure 1 The difference between the system shown is that: the separator 7 is not provided in the system; the outlet of the first gas-phase material is connected to the first gas-phase material inlet of the first pipeline and the second mixer 6B respectively;

[0197] Step S2 of the method comprises: mixing the first liquid phase material, at least a portion of the first gas phase material and the superheated primary dilution steam to obtain a first mixed flow;

[0198] At least part of the first gaseous material is mixed with the superheated secondary dilution steam in the second mixer 6B and superheated or vaporized to obtain a second mixed flow, and the second mixed flow enters the second gas-liquid separator 9; the second mixed flow enters the second gas-liquid separator 9 to contact with the third mixed flow for a second separation to obtain a second gaseous material and a second liquid material.

[0199] like Figure 3 As shown, in an exemplary embodiment of the system for producing olefins by steam cracking heavy hydrocarbons provided by the present disclosure, the system comprises:

[0200] Steam cracking device, first mixer 6A, second mixer 6B, third mixer 6C, first gas-liquid separator 8 and second gas-liquid separator 9;

[0201] The steam cracking device includes a convection section and a radiation section; along the height direction of the steam cracking device, the convection section is provided with a first heating section 1A, a boiler feed water preheating section BFW, a third heating section 3A, a fourth heating section 4, a fifth heating section 3B and a sixth heating section 5 from top to bottom; the radiation section includes a steam cracking inlet and a cracking product outlet;

[0202] The first gas-liquid separator 8 is provided with a gas-liquid separation inlet, a first gas-phase material outlet and a first liquid-phase material outlet; the second gas-liquid separator 9 is provided with a third mixed flow inlet, a second mixed flow inlet, a second gas-phase material outlet and a second liquid-phase material outlet;

[0203] Among them, the heating inlet of the first heating section 1A is used to introduce the heavy hydrocarbon to be preheated; the heating outlet of the first heating section 1A is connected to the gas-liquid separation inlet of the first gas-liquid separator 8; the first liquid phase material outlet of the first gas-liquid separator 8 is connected to the heating inlet of the fourth heating section 4 via the first pipeline; the heating inlet of the third heating section 3A is connected to the primary steam source, and the heating outlet of the third heating section 3A is connected to the first pipeline; the heating outlet of the fourth heating section 4 is connected to the third mixed flow inlet of the second gas-liquid separator 9, and a third mixer 6C is provided on the connecting pipeline;

[0204] The first gas-phase material outlet of the first gas-liquid separator 8 is connected to the first gas-phase material inlet of the second mixer 6B via the second pipeline; wherein the second mixer 6B is arranged on the second pipeline, and the first gas-phase material outlet of the first gas-liquid separator 8 is respectively connected to the first gas-phase material inlet of the second mixer 6B and the post-processing device; the heating inlet of the fifth heating section 3B is connected to the secondary steam source, and the heating outlet of the fifth heating section 3B is respectively connected to the secondary dilution steam inlet of the second mixer 6B and the secondary dilution steam inlet of the third mixer 6C on the second pipeline; the second mixed flow outlet of the second mixer 6B is connected to the second mixed flow inlet of the second gas-liquid separator 9; the second gas-phase material outlet of the second gas-liquid separator 9 is connected to the heating inlet of the sixth heating section 5, and the heating outlet of the sixth heating section 5 is connected to the radiation section of the steam cracking device; the second liquid-phase material outlet of the second gas-liquid separator 9 is connected to the post-processing device;

[0205] use Figure 3 The specific process flow of the system shown in the figure for producing olefins by steam cracking heavy hydrocarbons includes:

[0206] S1, allowing the heavy hydrocarbons to be preheated to enter the first heating section 1A for heating to obtain preheated heavy hydrocarbons; allowing the preheated heavy hydrocarbons to enter the first gas-liquid separator 8 for first separation to obtain a first gas phase material and a first liquid phase material;

[0207] S2, mixing at least part of the first liquid phase material with the primary dilution steam that has been superheated in the third heating section 3A in the first mixer 6A to obtain a first mixed flow, and then mixing the first mixed flow into the fourth heating section 4 for first heating and then with the secondary dilution steam that has been superheated in the fifth heating section 3B to obtain a third mixed flow;

[0208] At least part of the first gaseous material is mixed with the secondary dilution steam that has been superheated in the fifth heating section 3B and superheated or vaporized in the second mixer 6B to obtain a second mixed flow; another part of the first gaseous material enters the post-processing device;

[0209] The third mixed flow and the second mixed flow are mixed in the second gas-liquid separator 9 and then subjected to a second separation to obtain a second gas phase material and a second liquid phase material;

[0210] S3, allowing the second gaseous material to enter the sixth heating section 5 for a second heating and then enter the radiation section of the steam cracking device for steam cracking to obtain a cracking product containing olefins; allowing the second liquid-phase material to enter a post-processing device.

[0211] The present disclosure is further illustrated below by way of examples, but the present disclosure is not limited thereby.

[0212] Example 1

[0213] See the process of this embodiment for Figure 1 , using heavy hydrocarbons with an API value of 44, specifically including the following steps:

[0214] S1, after preliminary preheating, the heavy hydrocarbons from the storage tank are first preheated through the first heating section 1A of the convection section of the steam cracking unit, and the temperature of the first preheated heavy hydrocarbons is 112°C; the first preheated heavy hydrocarbons are sent to the second heating section 1B to obtain second preheated heavy hydrocarbons, and the temperature of the second preheated heavy hydrocarbons is 269°C, and the gasification rate is 26%;

[0215] The second preheated heavy hydrocarbon is used as the preheated heavy hydrocarbon to enter the first gas-liquid separator 8 for first separation to obtain a first gas phase material and a first liquid phase material; the first gas phase material contains a first light component with a mass fraction of 35 weight %; the first liquid phase material contains a first heavy component with a mass fraction of 65 weight %;

[0216] S2, the first liquid phase material and the superheated primary dilution steam after passing through the third heating section 3A are mixed, superheated and vaporized in the first mixer 6A to obtain a first mixed flow; the weight ratio of the first liquid phase material to the superheated primary dilution steam is 1:0.21; the temperature of the superheated primary dilution steam is 359°C, and the temperature of the first mixed flow is 259°C;

[0217] The first mixed flow enters the fourth heating section 4 for first heating, and the temperature of the first mixed flow after the first heating is 320°C; the first mixed flow after the first heating and the secondary dilution steam after superheating in the fifth heating section 3B are mixed, overheated and vaporized in the third mixer 6C to obtain a third mixed flow, and the third mixed flow enters the second gas-liquid separator 9; the weight ratio of the first liquid phase material to the superheated secondary dilution steam is 1:0.14; the temperature of the superheated secondary dilution steam is 551°C, the temperature of the third mixed flow is 318°C, and the vaporization rate is 59%;

[0218] The first gas phase material is sent to the separation tower 7 for the third separation to obtain a third gas phase material (the final distillation point temperature is 165°C) and a third liquid phase material (the initial distillation point temperature is ≥165°C); the third gas phase material is sent to other steam cracking devices or oil refining devices; the third liquid phase material is mixed with the secondary dilution steam superheated in the fifth heating section 3B in the second mixer 6B, and is gasified and superheated to obtain a second mixed flow, and the weight ratio of the third liquid phase material to the superheated secondary dilution steam is 1:0.40; the temperature of the second mixed flow is 453°C, and the second mixed flow is introduced through the lower part of the second gas-liquid separator 9, and cooling water is introduced into the second gas-liquid separator 9 at the same time, and the temperature in the second gas-liquid separator 9 is controlled to be 290-400°C;

[0219] The third mixed stream is mixed with the second mixed stream in the second gas-liquid separator 9 and then subjected to a second separation to obtain a second gas phase material and a second liquid phase material; the second gas phase material contains the carried steam and the second light component, and the second liquid phase material contains the second heavy component (the initial distillation point temperature is 430° C., and the flash point temperature of the second liquid phase material is controlled to be higher than 116° C. and meets the tank storage requirements); wherein the superheated second mixed stream strips the third mixed stream so that the impurities carried in the separated second gas phase material are washed or condensed;

[0220] S3, the second gaseous material enters the sixth heating section 5 for a second heating and then enters the radiation section of the steam cracking device for steam cracking; the steam cracking temperature is 802° C., and the radiation furnace tube residence time is 0.26 s; the second liquid phase material is sent to the oil refining device.

[0221] Example 2

[0222] See the process of this embodiment for Figure 2 , using heavy hydrocarbons with an API value of 38, specifically including the following steps:

[0223] S1. After preliminary preheating, heavy hydrocarbons from a storage tank are first preheated through a first heating section 1A of a convection section of a steam cracking unit, wherein the temperature of the first preheated heavy hydrocarbons is 115° C.; the first preheated heavy hydrocarbons are sent to a second heating section 1B to obtain second preheated heavy hydrocarbons, wherein the temperature of the second preheated heavy hydrocarbons is 235° C., and the gasification rate of the second preheated heavy hydrocarbons is 21%;

[0224] The second preheated heavy hydrocarbon is used as the preheated heavy hydrocarbon to enter the first gas-liquid separator 8 for first separation to obtain a first gas phase material and a first liquid phase material; the first gas phase material contains a first light component with a mass fraction of 32 weight %; the first liquid phase material contains a first heavy component with a mass fraction of 68 weight %;

[0225] S2, mixing at least part of the first gas phase material with the first liquid phase material and the superheated primary dilution steam after passing through the third heating section 3A, superheating and gasifying in the first mixer 6A to obtain a first mixed flow; wherein the weight ratio of the first liquid phase material to the superheated primary dilution steam is 1:0.18; the temperature of the superheated primary dilution steam is 290° C., and the temperature of the first mixed flow is 207° C.;

[0226] The first mixed flow enters the fourth heating section 4 for first heating, and the temperature of the first mixed flow after the first heating is 248°C; the first mixed flow after the first heating and the secondary dilution steam after superheating in the fifth heating section 3B are mixed, overheated and vaporized in the third mixer 6C to obtain a third mixed flow, and the third mixed flow enters the second gas-liquid separator 9; the weight ratio of the first liquid phase material to the superheated secondary dilution steam is 1:0.14; the temperature of the superheated secondary dilution steam is 418°C, the temperature of the third mixed flow is 232°C, and the vaporization rate is 41%;

[0227] At least part of the first gas phase material and the secondary dilution steam superheated by the fifth heating section 3B are mixed, vaporized and superheated in the second mixer 6A to obtain a second mixed flow, the temperature of the second mixed flow is 395°C, and the second mixed flow is introduced through the lower part of the second gas-liquid separator 9 to wash or condense the impurities carried in the separated second gas phase material, and cooling water is introduced into the second gas-liquid separator 9 to control the temperature in the second gas-liquid separator 9 to be 290-400°C; the weight ratio of the first gas phase material to the superheated secondary dilution steam is 1:0.50; the weight ratio of the first gas phase material in the second mixed flow to the first gas phase material in the first mixed flow is 1:2.70.

[0228] The third mixed flow is mixed with the second mixed flow in the second separator 9 and then subjected to a second separation to obtain a second gas phase material and a second liquid phase material, wherein the second gas phase material contains the carried steam and the second light component; and the second liquid phase material contains the second heavy component (the initial distillation point temperature is 414° C.);

[0229] S3, the second gas phase material enters the sixth heating section 5 for the second heating and then enters the radiation section of the steam cracking device for steam cracking; the steam cracking temperature is 800° C., and the radiation furnace tube residence time is 0.24 s; the second liquid phase material separated by the second gas-liquid separator 9 is sent to the oil refining device.

[0230] Example 3

[0231] See the process of this embodiment for Figure 3 , using heavy hydrocarbons with an API value of 38, specifically including the following steps:

[0232] S1, after preliminary preheating, the heavy hydrocarbons from the storage tank are first preheated through the first heating section 1A of the convection section of the steam cracking device, the first preheated heavy hydrocarbon temperature is 229° C., and the first preheated heavy hydrocarbon gasification rate is 20%;

[0233] The first preheated heavy hydrocarbon is used as the preheated heavy hydrocarbon to enter the first gas-liquid separator 8 for first separation to obtain a first gas phase material and a first liquid phase material; the first gas phase material contains a first light component with a mass fraction of 26 weight %; the first liquid phase material contains a first heavy component with a mass fraction of 74 weight %;

[0234] S2, the first liquid phase material and the superheated primary dilution steam after passing through the third heating section 3A are mixed and superheated in the first mixer 6A to obtain a first mixed flow; the weight ratio of the first liquid phase material to the superheated primary dilution steam is 1:0.21; the temperature of the superheated primary dilution steam is 374°C, and the temperature of the first mixed flow is 334°C;

[0235] The first mixed flow enters the fourth heating section 4 for first heating, and then is mixed with the secondary dilution steam that has been superheated in the fifth heating section 3B in the third mixer 6C for overheating and gasification to obtain a third mixed flow, and the third mixed flow enters the second gas-liquid separator 9, and the temperature of the first mixed flow after the first heating is 389°C; at least part of the first gas phase material and the secondary dilution steam that has been superheated in the fifth heating section 3B are second mixed, gasified and superheated in the second mixer 6B to obtain a second mixed flow, and the temperature of the second mixed flow is 313°C, and the second mixed flow is introduced through the lower part of the second gas-liquid separator 9; the weight ratio of the first gas phase material to the superheated secondary dilution steam is 1:0.54; the temperature of the superheated secondary dilution steam is 436°C; the weight ratio of the first liquid phase material to the superheated secondary dilution steam is 1:0.22; the temperature of the superheated secondary dilution steam is 502°C, the temperature of the third mixed flow is 378°C, and the gasification rate is 63%;

[0236] The third mixed flow is mixed with the second mixed flow in the second gas-liquid separator 9 and then subjected to a second separation to obtain a second gas phase material and a second liquid phase material;

[0237] The second gas phase material contains the entrained steam and the second light component; the second liquid phase material contains the second heavy component (the initial distillation point temperature is 402°C);

[0238] S3, the second gas phase material enters the sixth heating section 5 for the second heating and then enters the radiation section of the steam cracking device for steam cracking; the steam cracking temperature is 795° C., and the radiation furnace tube residence time is 0.24 s; the second liquid phase material separated by the second gas-liquid separator 9 is sent to the oil refining device.

[0239] Comparative Example 1

[0240] This comparative example process and embodiment Figure 3 The same method is used, using heavy hydrocarbons with an API value of 38. The specific steps are the same as those in Example 1, except that:

[0241] In step S1, the temperature of the first preheated heavy hydrocarbon is 182°C;

[0242] In step S2, the weight ratio of the first liquid phase material to the superheated primary dilution steam is 1:0.08; the temperature of the superheated primary dilution steam is 231°C;

[0243] The temperature of the first mixed flow after the first heating is 279°C; the temperature of the second mixed flow is 320°C; the weight ratio of the first gas phase material to the secondary dilution steam after superheating is 1:0.17; the temperature of the secondary dilution steam after superheating is 398°C;

[0244] The second gas phase material contains steam and a second light component, the second liquid phase material contains a second heavy component, the initial distillation point temperature is 348°C, and the second heavy component carries a large amount of the second light component;

[0245] The steam cracking temperature is 781°C and the radiation furnace tube residence time is 0.23s.

[0246] Through the above technical scheme, the method for producing olefins by steam cracking heavy hydrocarbons provided by the present disclosure can prevent or reduce the entrainment of heavy components in the gas phase components by selecting appropriate gasification conditions and component cutting methods. The present disclosure can completely use heavy hydrocarbons for direct cracking to produce olefins, greatly reducing the heavy hydrocarbon pre-treatment production equipment set in the traditional heavy hydrocarbon equipment, and producing olefins to the maximum extent with the shortest process and the minimum energy consumption.

[0247] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0248] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0249] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for steam cracking heavy hydrocarbons, characterized in that: The method comprises the following steps: S1, allowing the preheated heavy hydrocarbons to enter a first gas-liquid separator (8) for first separation to obtain a first gas phase material and a first liquid phase material; S2, mixing at least a portion of the first liquid phase material with a primary dilution steam to obtain a first mixed flow, and subjecting the first mixed flow to a first heating and then mixing it with at least a portion of a secondary dilution steam to obtain a third mixed flow; Mixing at least a portion of the first gas phase material with at least a portion of the secondary dilution steam to obtain a second mixed stream; allowing the third mixed flow and the second mixed flow to enter a second gas-liquid separator (9) for second separation to obtain a second gas phase material and a second liquid phase material; S3, subjecting the second gaseous material to a second heating and then entering the radiation section of a steam cracking device for steam cracking to obtain a cracking product containing olefins.

2. The method according to claim 1, wherein: Step S2 also includes: allowing at least a portion of the first gas phase material to enter a separation tower (7) for third separation to obtain a third gas phase material and a third liquid phase material; Mixing at least a portion of the third liquid phase material with the secondary dilution steam to obtain a second mixed flow, and allowing the second mixed flow to enter the second gas-liquid separator (9); The third mixed flow and the second mixed flow are subjected to a second separation in a second gas-liquid separator (9) to obtain a second gas phase material and a second liquid phase material.

3. The method according to claim 1, wherein: In step S1, the temperature of the preheated heavy hydrocarbon is 200-400°C, preferably 240-370°C; Optionally, the first gas phase material comprises a first light component, and the first liquid phase material comprises a first heavy component; Optionally, the gasification rate of the preheated heavy hydrocarbons is 20-65%, preferably 25-45%.

4. The method according to claim 1, wherein: The method further comprises: in step S2, first mixing at least a portion of the first gas phase material, the first liquid phase material and the primary dilution steam to obtain a first mixed flow; The weight ratio of the first liquid phase material to the primary dilution steam is 1:(0.1-0.5), preferably 1:(0.15-0.4); The weight ratio of the first liquid phase material to the secondary dilution steam is 1:(0-0.55), preferably 1:(0.10-0.35); Optionally, the method further comprises: in step S2, allowing at least a portion of the primary dilution steam to enter a third heating section (3A) for heating to obtain superheated primary dilution steam, and performing a first mixing of the superheated primary dilution steam, the first liquid-phase material and at least a portion of the first gas-phase material to obtain a first mixed flow; allowing at least a portion of the secondary dilution steam to enter a fifth heating section (3B) for heating to obtain superheated secondary dilution steam; Allowing the first mixed flow to enter a fourth heating section (4) for first heating and then to mix with at least a portion of the superheated secondary dilution steam to obtain a third mixed flow; Optionally, the temperature of the primary dilution steam after superheating is 240-400°C, preferably 280-385°C; Optionally, the temperature of the first mixed stream is 200-350°C, preferably 240-300°C; Optionally, the temperature of the first mixed stream after the first heating is below 400° C., preferably 285-370° C.; Optionally, the temperature of the superheated secondary dilution steam is 400-630° C., preferably 450-595° C.; Optionally, a weight ratio of the first gas-phase material in the second mixed flow to the first gas-phase material in the first mixed flow is 1:(0.90-153), preferably 1:(2.35-153).

5. The method according to claim 2, wherein: The second gaseous material contains steam and a second light component; the second liquid material contains a second heavy component; the final distillation temperature of the second light component is 330-500° C.; the second gaseous material contains no more than 1wt% of a heavy component having a carbon number of not less than 30, preferably no more than 0.5wt%; The initial distillation point temperature of the second heavy component is not higher than the final distillation point of the second light component; Optionally, step S2 also includes: Allow at least a portion of the first liquid phase material, at least a portion of the third liquid phase material and the primary dilution steam to enter a first mixer (6A) for mixing to obtain a first mixed flow; In the first mixed flow, the weight ratio of the first liquid phase material to the primary dilution steam is 1:(0.1-0.5), preferably 1:(0.15-0.4); Allowing at least a portion of the secondary dilution steam to enter a third mixer (6C) and mix with the first mixed flow to obtain a third mixed flow; Allow at least part of the first gaseous material and the secondary dilution steam to enter the second mixer (6B) for mixing, overheating or vaporization to obtain a second mixed flow; or allow at least part of the third liquid material and the secondary dilution steam to enter the second mixer (6B) for mixing, overheating or vaporization to obtain a second mixed flow; optionally, the weight ratio of the third liquid material in the second mixed flow to the third liquid material in the first mixed flow is 1:(2-154), preferably 1:(3.5-153); Optionally, the temperature of the second mixed stream is 300-550°C, preferably 325-500°C; Optionally, the temperature of the third mixed stream is 200-450°C, preferably 285-400°C; Optionally, a cooling aid is introduced into the gas phase space of the second gas-liquid separator (9), wherein the cooling aid comprises water and / or liquid hydrocarbons, wherein the liquid hydrocarbons comprise a diesel fraction; Optionally, at least part of the third liquid phase material is introduced into the upper part of the gas phase space of the second gas-liquid separator (9) as a cooling aid; Optionally, the first mixed flow and the cooling aid are introduced into the gas phase space of the second gas-liquid separator (9) in different directions; Preferably, the cooling aid is introduced into the gas phase space of the second gas-liquid separator (9) above the first mixed flow to cool the gas phase components in the first mixed flow; Optionally, the weight ratio of the first gas phase material or the third liquid phase material to the secondary dilution steam is 1:(0.2-4); preferably 1:(0.6-3.5); Optionally, the method further comprises: sending at least a portion of the first gaseous material for post-processing, wherein the post-processing comprises one or more of reforming, oil product processing of oil refining, and normal isomer separation, but does not comprise steam cracking.

6. The method according to claim 1 or 2, wherein: The steam cracking device comprises a convection section and a radiation section; along the height direction of the steam cracking device, the convection section at least comprises a first heating section (1A), an optional second heating section (1B), a third heating section (3A), a fourth heating section (4), a fifth heating section (3B) and a sixth heating section (5); Optionally, step S1 further includes: The heavy hydrocarbons to be preheated are allowed to enter the first heating section (1A) for first preheating to obtain first preheated heavy hydrocarbons; and then the first preheated heavy hydrocarbons are allowed to enter the first gas-liquid separator (8) as the preheated heavy hydrocarbons; Allowing at least a portion of the first preheated heavy hydrocarbons from the first heating section (1A) to enter the second heating section (1B) for heating to obtain second preheated heavy hydrocarbons; allowing the second preheated heavy hydrocarbons to enter the first gas-liquid separator (8) as the preheated heavy hydrocarbons; Optionally, the first preheated heavy hydrocarbon is subjected to a desalination treatment before being heated, or the heavy hydrocarbon to be preheated is subjected to a desalination treatment before being subjected to the first preheating.

7. A system for steam cracking heavy hydrocarbons, characterized in that: The system comprises a steam cracking device, a first gas-liquid separator (8) and a second gas-liquid separator (9); the steam cracking device comprises a convection section and a radiation section; The first gas-liquid separator (8) is configured to allow the preheated heavy hydrocarbons to enter therein for first separation to obtain a first gas phase material and a first liquid phase material; The second gas-liquid separator (9) is configured to allow the third mixed flow and the second mixed flow to enter therein for second separation to obtain a second gas phase material and a second liquid phase material; The radiant section of the steam cracking device is configured to steam crack at least a portion of the second gas phase material to obtain a cracking product containing olefins; The system further comprises a post-processing device configured to perform post-processing on at least a portion of the first gas-phase material sent outward.

8. The system according to claim 7, wherein: The convection section is provided with a raw material heating inlet and a raw material heating outlet; the radiation section is provided with a steam cracking inlet and a cracking product outlet; The first gas-liquid separator (8) is provided with a gas-liquid separation inlet, a first gas-phase material outlet and a first liquid-phase material outlet; the gas-liquid separation inlet of the first gas-liquid separator (8) is connected to the raw material heating outlet of the convection section; the first liquid-phase material outlet of the first gas-liquid separator (8) is connected to the steam cracking inlet of the radiation section; The second gas-liquid separator (9) is provided with a third mixed stream inlet, a second mixed stream inlet, an optional cooling aid inlet, a second gas phase material outlet and a second liquid phase material outlet; The cooling aid inlet includes a liquid hydrocarbon inlet and / or a water inlet; wherein the third mixed flow inlet of the second gas-liquid separator (9) is connected to the heating outlet of the fourth heating section (4); optionally, the first gas-phase material outlet of the first gas-liquid separator (8) is connected to the second mixed flow inlet of the second gas-liquid separator (9) via a second pipeline; The radiation section comprises a steam cracking inlet and a cracking product outlet; the outlet of the second gas phase material of the second gas-liquid separator (9) is connected to the steam cracking inlet of the radiation section.

9. The system according to claim 8, wherein: Along the height direction of the steam cracking device, the convection section at least includes a first heating section (1A), an optional second heating section (1B), a third heating section (3A), a fourth heating section (4), a fifth heating section (3B) and a sixth heating section (5); wherein the heating inlet of the first heating section (1A) is used to introduce the heavy hydrocarbons to be preheated; the heating outlet of the first heating section (1A) is connected to the gas-liquid separation inlet of the first gas-liquid separator (8); preferably, a pressure regulating valve is provided on the inlet pipeline of the gas-liquid separation inlet of the first gas-liquid separator (8) to control the preheating temperature of the heavy hydrocarbons entering the first gas-liquid separator (8); optionally, a pressure regulating valve is provided on the outlet pipeline of the first gas-phase material outlet to further control the gasification rate; The heating inlet of the fourth heating section (4) is connected to the first liquid material outlet of the first gas-liquid separator (8) via a first pipeline; the heating inlet of the third heating section (3A) is connected to a primary steam source; the heating outlet of the third heating section (3A) is connected to the first pipeline; The heating outlet of the fourth heating section (4) is connected to the third mixed flow inlet of the second gas-liquid separator (9); the heating inlet of the fifth heating section (3B) is connected to the secondary steam source; the heating outlet of the fifth heating section (3B) is respectively connected to the connecting pipeline between the heating outlet of the fourth heating section (4) and the third mixed flow inlet of the second gas-liquid separator (9) and the second pipeline; The heating inlet of the sixth heating section (5) is connected to the second gas-phase material outlet of the second gas-liquid separator (9); the heating outlet of the sixth heating section (5) is connected to the steam cracking inlet of the radiation section; Optionally, the second liquid phase material outlet of the second gas-liquid separator (9) can be used to communicate with a hydrocracking or catalytic cracking unit; Optionally, the second gas-liquid separator (9) is internally provided with at least one of a cooler, a tray and a hydrocyclone separator; Optionally, the system further comprises a separation tower (7); the separation tower (7) is provided with a first gas phase material inlet, a third gas phase material outlet and a third liquid phase material outlet; The first gas-phase material outlet of the first gas-liquid separator (8) is connected to the first gas-phase material inlet of the separation tower (7), and the third liquid-phase material outlet of the separation tower (7) is connected to the second mixed flow inlet of the second gas-liquid separator (9) via a third pipeline; the heating outlet of the fifth heating section (3B) is connected to the third pipeline; The third gas phase material outlet of the separation tower (7) is communicated with a post-processing device.

10. The system according to claim 9, wherein: Optionally, a first mixer (6A) is provided on the first pipeline, for mixing the first liquid-phase material and the primary dilution steam therein to be superheated or vaporized to obtain a first mixed flow; The second pipeline is provided with a second mixer (6B) for mixing the first gaseous material and the secondary dilution steam therein to be superheated or gasified to obtain a second mixed flow; Optionally, a third mixer (6C) is further provided on the connecting pipeline between the heating outlet of the fourth heating section (4) and the third mixed flow inlet of the second gas-liquid separator (9), for mixing the first mixed flow with at least part of the secondary dilution steam to be superheated or vaporized to obtain a third mixed flow; The first mixer (6A) is provided with a first liquid material inlet, a primary dilution steam inlet and a first mixed flow outlet; the first liquid material outlet of the first gas-liquid separator (8) is connected to the first liquid material inlet of the first mixer (6A), the heating outlet of the third heating section (3A) is connected to the primary dilution steam inlet of the first mixer (6A); the first mixed flow outlet of the first mixer (6A) is connected to the heating inlet of the fourth heating section (4); The second mixer (6B) is provided with a first gas-phase material inlet, a secondary dilution steam inlet and a second mixed flow outlet; the first gas-phase material outlet of the first gas-liquid separator (8) is connected to the first gas-phase material inlet of the second mixer (6B), and the second mixed flow outlet of the second mixer (6B) is connected to the second mixed flow inlet of the second gas-liquid separator (9); The third mixer (6C) is provided with a first mixed flow inlet, a secondary dilution steam inlet and a third mixed flow outlet; the heating outlet of the fourth heating section (4) is connected to the first mixed flow inlet of the third mixer (6C), the heating outlet of the fifth heating section (3B) is respectively connected to the secondary dilution steam inlet of the second mixer (6B) and the secondary dilution steam inlet of the third mixer (6C), and the third mixed flow outlet of the third mixer (6C) is connected to the third mixed flow inlet of the second gas-liquid separator (9); Optionally, the outlet of the first gas-phase material is connected to the first gas-phase material inlet of the first pipeline and the second mixer (6B), respectively; Alternatively, the second mixer (6B) is arranged on the third pipeline, and is used to mix the third liquid phase material and the secondary dilution steam therein, and superheat or vaporize them to obtain a second mixed flow; the second mixer (6B) is provided with a third liquid phase material inlet, a secondary dilution steam inlet and a second mixed flow outlet; the third liquid phase material outlet of the separation tower (7) is connected to the third liquid phase material inlet of the second mixer (6B), the heating outlet of the fifth heating section (3B) is respectively connected to the secondary dilution steam inlet of the second mixer (6B) and the secondary dilution steam inlet of the third mixer (6C), and the second mixed flow outlet of the second mixer (6B) is connected to the second mixed flow inlet of the second gas-liquid separator (9); Optionally, the heating outlet of the first heating section (1A) is connected to the heating inlet of the second heating section (1B); the heating outlet of the second heating section (1B) is connected to the gas-liquid separation inlet of the first gas-liquid separator (8); Optionally, the outlet of the third liquid-phase material is connected to the first pipeline and the third liquid-phase material inlet of the second mixer (6B), respectively.

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