A method and system for steam cracking heavy hydrocarbons

Abstract

The present disclosure relates to a method and system for steam cracking heavy hydrocarbon, which makes the heavy hydrocarbon enter a first gas-liquid separator, separates the first liquid phase material obtained by separation, mixes and heats the first liquid phase material with dilution steam, and then makes the first liquid phase material enter a second gas-liquid separator for separation, and uses at least part of the first gas phase material obtained by separation and all of the second gas phase material to produce a cracking product including olefins by steam cracking, so that the heavy hydrocarbon can be directly cracked to produce olefins or used for other purposes, the production device for pretreatment of heavy hydrocarbon in a traditional oil refining device is greatly reduced, the energy consumption for producing olefins is minimized, and the process is shortened.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of petroleum chemical technology, in particular, to a method and system for steam cracking heavy hydrocarbon. BACKGROUND

[0002] Compared with traditional cracking feedstock, heavy hydrocarbon (crude oil, etc.) has high end boiling point (greater than 520℃), contains impurities such as resin and asphaltene, is not easy to vaporize, and is prone to coking when used as a steam cracking furnace feedstock. Therefore, the design of the cracking furnace and the production process need to be handled and improved accordingly to adapt to the characteristics of heavy hydrocarbon (crude oil, etc.).

[0003] CN111196936A discloses a combined processing method and device for producing olefins by cracking crude oil. The method first removes impurities through pretreatment such as desalting and dewatering, then sends the feedstock into the convection section of the ethylene cracking furnace for heating, and the heated feedstock is sent into a gas-liquid separator. The lighter diesel and lighter components are separated and sent into the convection section and the radiant section for steam cracking reaction to produce olefins. The liquid phase from the gas-liquid separator contains atmospheric residue and other components, which is sent into a hydrogenation unit for further treatment and then returned to the convection section and the radiant section. This method can use less components of crude oil.

[0004] CN107001955A discloses a method for thermal cracking of crude oil and heavy feedstock in a pyrolysis reactor to produce olefins. The method describes a scheme of a cracking furnace convection section and a multi-stage (up to 3 stages) separator or a combination with a fractionating column. The method can perform gas-liquid separation of a mixture of crude oil and steam multiple times, and send mixtures of different weights into different radiant section furnace tubes for cracking. The method mentions that when heavier fractions need to be vaporized, the crude oil is preheated in an external heat exchanger before entering the convection section of the cracking furnace, but does not specify the source of heat exchange. The method separates the mixture through a multi-stage separator, a fractionating column, and different radiant furnace tubes to crack different fractions, which is only suitable for cracking the separated light components, and cannot meet the requirement of providing feedstock for downstream processing devices.

[0005] CN100564484A discloses a method for cracking heavy hydrocarbon feedstock, wherein the heavy hydrocarbon feedstock mainly includes 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-liquid components well through simple flash vaporization. The method is only suitable for cracking the separated light components, and cannot meet the requirement of providing feedstock for downstream processing devices.

[0006] CN101528894A and CN101778929A introduce the process technology of using crude oil / condensate cracking to produce ethylene. CN101528894A introduces that the light components separated from the preheated crude oil / condensate in the convection section enter the cracking furnace convection section after being superheated and then enter the radiation section for cracking, and the heavy components are sent to the atmospheric tower and / or vacuum tower for further separation, and CN101778929A introduces that the heavy materials such as crude oil or condensate mixed in the raw materials at 30% by weight are preheated in the convection section and then enter the upper separation device to separate the protective naphtha and lighter components, and the separated liquid phase enters the lower packing tower for further separation, and how to treat the separated heavy components is not introduced. The evaporation unit of the two patents adopts a stripping tower containing packing or trays, and the evaporation zone at the upper part contains a gas-liquid separator, which can realize gas-liquid separation.

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

[0008] The methods disclosed in the prior art control the constant flash vaporization rate by various methods, use special flash equipment to achieve as much flash as possible and control the entrainment of heavy components in the gas phase components, but most of the equipment requires relatively high crude oil for primary separation or the flash process is complex for multi-stage separation, and the separated gas phase is sent to the radiation section for cracking and the separated liquid phase components are further separated, without utilizing the separated gas phase components to control the inlet process conditions of the secondary gas-liquid separation, the vaporization rate and the entrainment of light components in the liquid phase components, and without sending the gas phase components to other downstream devices for further production of other products. SUMMARY

[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 conventional method and system, is easy to operate, realizes flexible cutting of heavy hydrocarbons, takes into account the raw material supply of ethylene cracking devices and oil refining related processing devices such as reforming devices, and the gas-liquid separation method is efficient, which can effectively solve the problems of impurities in heavy components and entrainment of light components in the gas-liquid separation process, realize efficient conversion of heavy hydrocarbons and reduce the energy consumption of ethylene devices.

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

[0011] S1, making the preheated heavy hydrocarbons 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 part of the first liquid phase material with primary dilution steam to obtain a first mixture stream, and mixing the first mixture stream with at least part of secondary dilution steam after first heating to obtain a third mixture stream;

[0013] mixing at least part of the first gas phase material with at least part of the secondary dilution steam to obtain a second mixture stream, and feeding the second mixture stream into a second gas-liquid separator;

[0014] mixing the third mixture stream with the second mixture stream after entering the second gas-liquid separator to perform second separation, to obtain a second gas phase material and a second liquid phase material;

[0015] S3, feeding the second gas phase material into a radiant section of a steam cracking device after second heating to perform steam cracking, to obtain a cracking product containing olefins.

[0016] Optionally, step S2 further comprises: feeding at least part of the first gas phase material into a separation tower to perform third separation, to obtain a third gas phase material and a third liquid phase material;

[0017] mixing at least part of the third liquid phase material with the secondary dilution steam to obtain a second mixture stream, and feeding the second mixture stream into the second gas-liquid separator;

[0018] the third mixture stream and the second mixture stream are subjected to second separation in the second gas-liquid separator, to obtain a second gas phase material and a second liquid phase material.

[0019] In step S1, the temperature of the preheated heavy hydrocarbon is 200-400℃, preferably 240-370℃;

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

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

[0022] In step S2, at least part of the first gas phase material, the first liquid phase material, and the primary dilution steam are subjected to first mixing to obtain a first mixture stream; 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 mixture stream to the first gas phase material in the first mixture stream is 1:(0.90-153), preferably 1:(2.35-153).

[0025] Optionally, the method further comprises: in step S2, heating at least part of the primary dilution steam in a third heating section to obtain superheated primary dilution steam; mixing the superheated primary dilution steam, the first liquid phase material, and at least part of the first gas phase material to obtain a first mixture stream;

[0026] Heating at least part of the secondary dilution steam in a fifth heating section to obtain superheated secondary dilution steam;

[0027] Mixing the first mixture stream with at least part of the superheated secondary dilution steam after the first mixture stream is heated in a fourth heating section to obtain a third mixture stream;

[0028] Optionally, the temperature of the superheated primary dilution steam is 240-400℃, preferably 280-385℃;

[0029] Optionally, the temperature of the first mixture stream is 200-350℃, preferably 240-300℃;

[0030] Optionally, the temperature of the first mixture stream after the first heating is below 400℃, preferably 285-370℃;

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

[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] The second gas phase material contains steam and a second light component; the second liquid phase material contains a second heavy component; the terminal boiling point temperature of the second light component is 330-500℃; the heavy component with carbon atom number not less than 30 carried by the second gas phase material is not more than 1wt%, preferably not more than 0.5wt%; the initial boiling point temperature of the second heavy component is not higher than the terminal boiling point of the second light component, and the flash point temperature of the second liquid phase material meets the storage requirement.

[0034] Optionally, step S2 further comprises:

[0035] At least part of the first gas phase material is sent out for post-treatment, and the post-treatment does not include steam cracking;

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

[0037] The first mixture stream is obtained by mixing at least part of the first liquid phase material, at least part of the third liquid phase material and the primary dilution steam in a first mixer;

[0038] The weight ratio of the first liquid phase material to the primary dilution steam in the first mixture stream 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 mixture stream to the third liquid phase material in the first mixture stream is 1:(0.90-153), preferably 1:(2.35-153).

[0040] The third mixture stream is obtained by mixing at least part of the secondary dilution steam and the first mixture stream in a third mixer;

[0041] The second mixture stream is obtained by mixing at least part of the first gas phase material and the secondary dilution steam in a second mixer, or by mixing at least part of the third liquid phase material and the secondary dilution steam in a second mixer;

[0042] Optionally, the temperature of the second mixture stream is 300-550℃, preferably 325-500℃;

[0043] Optionally, the temperature of the third mixture stream is 200-450℃, preferably 285-400℃.

[0044] Preferably, the third mixture stream and the second mixture stream enter the liquid phase space of a second gas-liquid separator to perform a second separation, obtaining 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 vaporization rate and the entrainment of heavy components in the gas phase components, ultimately achieving efficient cracking and prolonging the decoking cycle; optionally, the cooling aid includes water and / or liquid hydrocarbon; 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 mixture stream is stripped against the liquid phase component in the third mixture stream to control the content of light components in the second liquid phase material obtained by separation; the liquid phase component obtained by further separation of the second mixture stream is contacted with the third mixture stream in the second gas-liquid separator, which can control the vaporization 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 comprises:

[0050] The heavy hydrocarbon to be preheated is subjected to first preheating in the first heating section to obtain first preheated heavy hydrocarbon; and then the first preheated heavy hydrocarbon is introduced into the first gas-liquid separator as the preheated heavy hydrocarbon;

[0051] At least part of the first preheated heavy hydrocarbon from the first heating section is introduced into the second heating section for heating to obtain second preheated heavy hydrocarbon; and the second preheated heavy hydrocarbon is introduced into the first gas-liquid separator as the preheated heavy hydrocarbon;

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

[0053] Another aspect of the present disclosure also provides a system for steam cracking heavy hydrocarbon, which comprises 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 subject the preheated heavy hydrocarbon to first separation therein to obtain a first gas phase material and a first liquid phase material;

[0055] The second gas-liquid separator is configured to subject a third mixture stream and a second mixture stream to second separation therein to obtain a second gas phase material and a second liquid phase material;

[0056] The radiation section of the steam cracking device is configured to subject at least part of the second gas phase material to steam cracking to obtain a cracking product comprising olefins;

[0057] The system further comprises a post-treatment device configured to post-treat the at least partial first gas phase material outfeed.

[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 in communication with the raw material heating outlet of the convection section; the first liquid phase material outlet of the first gas-liquid separator is in communication with the steam cracking inlet of the radiation section;

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

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

[0062] The third mixture flow inlet of the second gas-liquid separator is in communication with the heating outlet of the fourth heating section; optionally, the first gas phase material outlet of the first gas-liquid separator is in communication with the second mixture 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 second gas phase material outlet of the second gas-liquid separator is in communication with the steam cracking inlet of the radiation section.

[0064] 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 along the height direction of the steam cracking device;

[0065] The heating inlet of the first heating section is used to introduce the heavy hydrocarbon to be preheated; the heating outlet of the first heating section is in communication with the gas-liquid separation inlet of the first gas-liquid separator; preferably, a pressure regulating valve is arranged on the introduction pipeline of the gas-liquid separation inlet of the first gas-liquid separator, so as to control the preheating temperature of the heavy hydrocarbon entering the first gas-liquid separator; optionally, a pressure regulating valve is arranged on the introduction pipeline of the first gas phase material outlet, so as to further control the gasification rate;

[0066] The heating inlet of the fourth heating section is in communication with 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 in communication with 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 communication line between the heating outlet of the fourth heating section and the third mixture flow inlet of the second gas-liquid separator and the second line;

[0068] the heating inlet of the sixth heating section is communicated with the second gas phase material outlet of the second gas-liquid separator; and 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 device.

[0070] Optionally, the second gas-liquid separator is internally provided with a structure of a tray, a cooler and a hydrocyclone or a combination of at least two thereof.

[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 communicated with the first gas phase material inlet of the separation tower, the third liquid phase material outlet of the separation tower is communicated with the second mixture flow inlet of the second gas-liquid separator via a third line; and the heating outlet of the fifth heating section is connected to the third line.

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

[0074] Optionally, the first line is further provided with a first mixer for mixing and superheating or gasifying the first liquid phase material and the primary dilution steam in the first mixer to obtain a first mixture flow.

[0075] the second line is further provided with a second mixer for mixing and superheating or gasifying the first gas phase material and the secondary dilution steam in the second mixer to obtain a second mixture flow.

[0076] Optionally, the communication line between the heating outlet of the fourth heating section and the third mixture flow inlet of the second gas-liquid separator is further provided with a third mixer for mixing and superheating or gasifying the first mixture flow and at least part of the secondary dilution steam in the third mixer to obtain a third mixture flow.

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

[0078] The second mixer is provided with a first gas material inlet, a secondary dilution steam inlet and a second mixture outlet; the first gas material inlet of the second mixer is communicated with the first gas material outlet of the first gas-liquid separator, and the second mixture outlet of the second mixer is communicated with the second mixture inlet of the second gas-liquid separator;

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

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

[0081] Alternatively, the second mixer is arranged on the third pipeline to mix the third liquid material with the secondary dilution steam to obtain a second mixture; the second mixer is provided with a third liquid material inlet, a secondary dilution steam inlet and a second mixture outlet;

[0082] The third liquid material outlet of the separation tower is communicated with the third liquid material inlet of the second mixer; the heating outlet of the fifth heating section is respectively communicated with the secondary dilution steam inlet of the second mixer and the secondary dilution steam inlet of the third mixer; and the second mixture outlet of the second mixer is communicated with the second mixture 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; and 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 material is respectively connected to the first pipeline and the third liquid material inlet of the second mixer.

[0085] By the technical scheme, the method and system for steam cracking heavy hydrocarbon are provided, and beneficial effects at least include: (1) the first gas-liquid separator is arranged to preliminarily separate the heavy hydrocarbon, so that the size of the next separation device is reduced and the energy consumed by separation is reduced when part of the first gas phase material is further separated, and the light component content and flash point of the liquid phase component in the device can be optionally controlled by not separating part of the first gas phase material to enter the next separation device as a gas stripping agent; the cooling aid is in the same layer with the third mixture flow and the second mixture flow in the second gas-liquid separator, or is mixed with or countercurrently contacted with the gas phase component after separation, so as to control the gasification rate and the heavy component entrainment in the gas phase component, and finally achieve the purposes of efficient cracking and prolonging the decoking cycle; (2) the two-stage separation is arranged, and the heavy hydrocarbon has a wide adaptation range, so that at least three different narrow distillation range components can be cut according to the properties of the heavy hydrocarbon of different distillation range components, and the separation effect is improved to realize efficient cracking of the heavy hydrocarbon, high olefin yield, and maximum application of the existing steam cracking technology, which is mature and simple to operate; (3) the first gas phase material in the second mixture flow is used as a gas stripping agent to be countercurrently contacted with the liquid phase material obtained after the third mixture flow enters the second gas-liquid separator, so that the content of the gas phase component entrained in the second liquid phase component can be effectively controlled, and the light component of the heavy hydrocarbon is fully utilized to improve the utilization rate and the olefin yield; (4) the temperature of the second mixture flow is controlled below 550 DEG C, so that the liquid phase material in the second gas-liquid separator is prevented from being contacted at a too high temperature to produce coking products by cracking reaction, and the coking products are entrained into the radiant section to cause coking in the radiant section; on the other hand, the requirement for the material of the gas-liquid separation device is reduced, so that the production cost is reduced, and the light component in the first liquid phase material is introduced into the first gas phase material as much as possible to improve the utilization rate of the wide distillation range hydrocarbon; (5) the raw material is provided for the downstream device, the downstream separation device is flexibly arranged, and appropriate cutting is performed to realize "olefin if appropriate, aromatic if appropriate, and oil if appropriate", realize the upgrading and efficiency improvement of the existing refining integrated device, and also be used for producing olefin in the new refining integrated device.

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

[0087] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and together with the specific embodiments below, serve to explain the present disclosure but do not constitute a limitation on the present disclosure. In the drawings:

[0088] Figure 1 is an exemplary flow chart of the present disclosure for producing olefin by steam cracking of heavy hydrocarbon.

[0089] Figure 2is one exemplary flow chart for steam cracking of heavy hydrocarbons to produce olefins provided by the present disclosure.

[0090] Figure 3 is one exemplary flow chart for steam cracking of heavy hydrocarbons to produce olefins provided by the present disclosure.

[0091] BRIEF DESCRIPTION OF DRAWINGS

[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 column; 8 - first gas-liquid separator; 9 - second gas-liquid separator. DETAILED DESCRIPTION

[0093] The specific embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

[0094] In the present disclosure, the words "first", "second", "third" and the like used herein are merely used to distinguish different components and do not contain actual meanings such as the order of connection and the like, unless otherwise stated. In the present disclosure, the orientation words such as "upper", "lower", "top" and "bottom" generally refer to the upper and lower, top and bottom in the normal use state of the device.

[0095] In the present disclosure, the words "primary dilution steam", "secondary dilution steam" and the like used herein are merely used to distinguish the introduced steam in different steps, and do not contain actual meanings such as the nature of the steam itself.

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

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

[0098] S1, introducing the preheated heavy hydrocarbons into a 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 part of the first liquid phase material with primary dilution steam to obtain a first mixture stream, and mixing at least part of the secondary dilution steam with the first mixture stream after first heating to obtain a third mixture stream;

[0100] mixing at least part of the first gas phase material with at least part of the secondary dilution steam to obtain a second mixture stream;

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

[0102] S3, the second gas phase material is heated and then enters a radiant 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, naphthenic-based crude oil, condensate oil, gasoline, kerosene, diesel, tail oil, fuel oil, reforming oil, etc. processed by a refinery device such as atmospheric and vacuum distillation, reforming, catalysis, coking, etc.

[0104] The present disclosure provides a process and system for steam cracking heavy hydrocarbons to produce olefins. The heavy hydrocarbons are preheated and then separated in a first gas-liquid separator 8. The separated first liquid phase material and first gas phase material are mixed with dilution steam and then sent to a second gas-liquid separator 9 for a second separation. The second gas phase material obtained by the second separation is heated and then sent to a radiant section of a steam cracking device for steam cracking. The process realizes the subdivision of different distillation range components, is suitable for a wide range of heavy hydrocarbons, and can flexibly utilize the separated fractions to maximize the use of existing steam cracking technology.

[0105] The present disclosure provides a process and system for steam cracking heavy hydrocarbons to produce olefins. The heavy hydrocarbons are preheated and then separated in a first gas-liquid separator 8. The separated first liquid phase material and first gas phase material are mixed with dilution steam and then sent to a second gas-liquid separator 9 for a second separation. The second gas phase material obtained by the second separation is heated and then sent to a radiant section of a steam cracking device for steam cracking. The process realizes the subdivision of different distillation range components, is suitable for a wide range of heavy hydrocarbons, and can flexibly utilize the separated fractions to maximize the use of existing steam cracking technology.

[0106] The present disclosure provides a process and system for steam cracking heavy hydrocarbons to produce olefins. The heavy hydrocarbons are preheated and then separated in a first gas-liquid separator 8. The separated first liquid phase material and first gas phase material are mixed with dilution steam and then sent to a second gas-liquid separator 9 for a second separation. The second gas phase material obtained by the second separation is heated and then sent to a radiant section of a steam cracking device for steam cracking. The process realizes the subdivision of different distillation range components, is suitable for a wide range of heavy hydrocarbons, and can flexibly utilize the separated fractions to maximize the use of existing steam cracking technology.

[0107] The post-treatment in the present disclosure is reforming, oil processing treatment of oil refining, normal-isomer separation and other treatment modes not including steam cracking, which can effectively separate heavy hydrocarbons with high aromatic content. The heavy hydrocarbons include mixed hydrocarbons with wide distillation range, and the end boiling point is above 540℃, for example, the heavy hydrocarbons can have an initial boiling point of 15℃ and an end boiling point of above 750℃, or a mixture of hydrocarbons containing components that are prone to coking under cracking furnace operating conditions.

[0108] The radiant section furnace tube of the present disclosure is also provided with a twisted fin heat transfer element or other coking inhibition element to avoid the entrainment of excessive heavy components with carbon atom number of 30 or more in the second gas phase material.

[0109] In one embodiment, the method provided by the present disclosure further includes introducing a cooling aid into the second gas-liquid separator 9, and 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 mixture flow to cool the gas phase components in the first mixture flow.

[0110] In the present disclosure, the at least part of the first gas phase material and / or the cooling aid is introduced into the gas phase space of the second gas-liquid separator 9 and contacted with the second gas phase material therein, and when the temperature is higher than a certain range and the vaporization rate reaches a certain value, the at least part of the first gas phase material as the reflux or washing of gas-liquid separation can effectively prevent the entrainment of heavy distillate and avoid impurities entering the radiant section to cause furnace tube coking and other phenomena; the impurities include one or more of gum, 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 the separation column 7 for third separation to obtain a third gas phase material and a third liquid phase material;

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

[0113] The third mixture flow and the second mixture flow are subjected to 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 enter the second gas-liquid separator 9 as a cooling aid 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 gas phase material to the water is 1:(0.01-0.2), preferably 1:(0.05-0.15); or the weight ratio of the second gas phase 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 comprises that the cooling aid introduction mode is selected from at least one of the following modes: in the axial direction of the second gas-liquid separator 9, the water introduction position is above the liquid hydrocarbon introduction position; or in the axial direction of the second gas-liquid separator 9, the water introduction position is below the liquid hydrocarbon introduction position; or in the axial direction of the second gas-liquid separator 9, the water introduction position is in the same plane as the liquid hydrocarbon introduction position.

[0118] In an embodiment, in step S1, the preheated heavy hydrocarbon has a temperature of 200-400°C, preferably 240-370°C.

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

[0120] In the present disclosure, the heavy hydrocarbon is preheated and the preheating temperature and the gasification rate of the heavy hydrocarbon in the convection section of the steam cracking device are controlled, so as to control the tube wall temperature of the convection section.

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

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

[0123] In a preferred embodiment, step S1 further comprises: the first preheated heavy hydrocarbon is subjected to desalting treatment before heating, and the flue gas obtained by the desalting pretreatment can further heat the first preheated heavy hydrocarbon; or the heavy hydrocarbon to be preheated is subjected to desalting treatment before entering the first heating section 1A for first preheating. The present disclosure couples the steam cracking device with the electric desalting device, which is conducive to comprehensive utilization of energy, reduction of energy consumption and increase of applicability to heavy hydrocarbons.

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

[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 one preferred embodiment, the method further comprises: in step S2, heating at least part of the primary dilution steam in the third heating section 3A to obtain superheated primary dilution steam, and mixing the superheated primary dilution steam, the first liquid phase material and at least part of the first gas phase material to obtain a first mixture stream;

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

[0130] Heating at least part of the secondary dilution steam in the fifth heating section 3B to obtain superheated secondary dilution steam;

[0131] Mixing the first mixture stream with at least part of the superheated secondary dilution steam after the first heating in the fourth heating section 4 to obtain a third mixture stream;

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

[0133] The temperature of the first mixture stream is 200-350℃, preferably 240-300℃.

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

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

[0136] Optionally, the temperature of the third mixture stream is 200-450℃, preferably 285-400℃.

[0137] In one embodiment, step S2 further comprises:

[0138] At least part of the first liquid phase material, at least part of the third liquid phase material and the primary dilution steam are mixed in a first mixer 6A to superheat or vaporize, obtaining a first mixture stream; at least part of the secondary dilution steam and the first mixture stream are mixed in a third mixer 6C to superheat or vaporize, obtaining a third mixture stream;

[0139] At least part of the first gas phase material and the secondary dilution steam are mixed in a second mixer 6B to superheat or vaporize, obtaining a second mixture stream;

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

[0141] Optionally, the present disclosure introduces at least part 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 the first mixture stream, for controlling the temperature of the first mixture stream, and further controlling the vaporization rate and the content of heavy components to prevent coking of the convection section, which can be flexibly adapted to various heavy hydrocarbon feedstocks.

[0142] Alternatively, at least part of the third liquid phase material and the secondary dilution steam are mixed in a second mixer 6B to superheat or vaporize, obtaining a second mixture stream;

[0143] The second mixture stream is introduced into the liquid phase space or above the liquid surface of the second gas-liquid separator 9, and the third mixture stream and the second mixture stream are subjected to a second separation in the second gas-liquid separator 9, obtaining a second gas phase material and a second liquid phase material;

[0144] Optionally, the temperature of the second mixture stream is 300-550℃, preferably 325-500℃;

[0145] In the present disclosure, at least part of the first gas phase material is mixed with the secondary steam to obtain a second mixture stream as a stripping agent, and the temperature of the second mixture stream is controlled to be lower than 550℃, preventing the heavy components in the third mixture material from coking due to contact with high-temperature gas during the stripping process, and the material grade of the second gas-liquid separator can be reduced 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 part of the first gas phase material to a post-treatment, the post-treatment comprising one or more of reforming treatment, oil product processing treatment of oil refining, normal-paraffin-isoparaffin separation, and not including steam cracking.

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

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

[0150] In one 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 the heavy hydrocarbon, the first light component has an initial boiling point temperature ≤270°C and a final boiling point temperature between 265-275°C; the first heavy component is in equilibrium with the first light component; the second light component has a final boiling point temperature of 330-500°C; the second gas phase material has no more than 1wt% of heavy components with carbon atom number no less than 30, preferably no more than 0.5wt%; the second heavy component is in equilibrium with the second light component; the third light component mainly comprises C1-C6 components, has a final boiling point temperature ≤90°C, and is sent to other cracking furnaces for cracking; the first middle fraction mainly comprises C6-C 10 components, has a distillation range of 80-180°C, and is sent to a reforming device; and the third heavy component has a distillation range of 180-380°C, mainly comprises C 11 and the above components, and is returned to the cracking furnace for cracking. It should be understood that the initial boiling point or the final boiling point of each fraction in the present disclosure is a range value, and in actual operation, it can be any temperature within the range. Moreover, the present disclosure can select the separated fractions according to actual production needs. The first middle component in the present disclosure has a high aromatic content, and is not suitable for steam cracking, and can be flexibly sent to an oil refining device such as reforming as a raw material, so as to achieve the principle of "aromatics for aromatics, olefins for olefins, and oil for oil".

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

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

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

[0155] The first gas-liquid separator 8 is configured to allow preheated heavy hydrocarbon to enter for first separation, obtaining a first gas phase material and a first liquid phase material;

[0156] The second gas-liquid separator 9 is configured to allow the third mixture stream and the second mixture stream to enter for second separation, obtaining a second gas phase material and a second liquid phase material;

[0157] The radiant section of the steam cracking device is configured to allow at least part of the second gas phase material to undergo steam cracking, obtaining a cracking product comprising olefins;

[0158] The system further comprises a post-treatment device configured to post-treat at least part of the first gas phase material sent out, the post-treatment device not comprising a steam cracking device.

[0159] The convection section is provided with a raw material heating inlet and a raw material heating outlet; the radiant 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 in communication with the raw material heating outlet of the convection section; the first liquid phase material outlet of the first gas-liquid separator 8 is in communication with the steam cracking inlet of the radiant section;

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

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

[0163] The third mixture stream inlet of the second gas-liquid separator 9 is in communication with the heating outlet of the fourth heating section 4; optionally, the first gas phase material outlet of the first gas-liquid separator 8 is in communication with the second mixture stream inlet of the second gas-liquid separator 9 via a second pipeline;

[0164] The radiant section comprises a steam cracking inlet and a cracking product outlet; the second gas phase material outlet of the second gas-liquid separator 9 is in communication with the steam cracking inlet of the radiant section.

[0165] The convection section 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 along the height direction of the steam cracking device;

[0166] The heating inlet of the first heating section 1A is used for introducing the heavy hydrocarbon to be preheated; the heating outlet of the first heating section 1A is communicated with the gas-liquid separation inlet of the first gas-liquid separator 8; preferably, a pressure regulating valve is arranged on the introduction pipeline of the gas-liquid separation inlet of the first gas-liquid separator 8, so as to control the preheating temperature of the heavy hydrocarbon entering the first gas-liquid separator 8; optionally, a pressure regulating valve is arranged on the introduction pipeline of the first gas phase material outlet, so as to further control the gasification rate;

[0167] The heating inlet of the fourth heating section 4 is communicated with the first liquid phase material outlet of the first gas-liquid separator 8 via a first pipeline; the heating inlet of the third heating section 3A is communicated with a primary steam source; and 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 communicated with the third mixed material flow inlet of the second gas-liquid separator 9; the heating inlet of the fifth heating section 3B is communicated with a secondary steam source; and the heating outlet of the fifth heating section 3B is connected to the communication pipeline of the heating outlet of the fourth heating section 4 and the third mixed material flow inlet of the second gas-liquid separator 9 and the second pipeline;

[0169] The heating inlet of the sixth heating section 5 is communicated with the second gas phase material outlet of the second gas-liquid separator 9; and the heating outlet of the sixth heating section 5 is communicated with 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 device;

[0171] Optionally, at least one of a cooler, a tray and a hydrocyclone is arranged 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 communicated with the first gas phase material inlet of the separation tower 7, and the third liquid phase material outlet of the separation tower 7 is communicated with the second mixed material flow inlet of the second gas-liquid separator 9 via a third pipeline; and 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 connected to a post-treatment device.

[0175] Optionally, a first mixer 6A is arranged on the first pipeline, for mixing the first liquid phase material and the primary dilution steam therein to obtain a first mixture stream;

[0176] Optionally, a second mixer 6B is arranged on the second pipeline, for mixing the first gas phase material and the secondary dilution steam therein to obtain a second mixture stream;

[0177] Optionally, a third mixer 6C is arranged on the pipeline connecting the heating outlet of the fourth heating section 4 and the third mixture stream inlet of the second gas-liquid separator 9, for mixing the first mixture stream and at least part of the secondary dilution steam therein to obtain a third mixture stream;

[0178] The first mixer 6A is provided with a first liquid phase material inlet, a primary dilution steam inlet and a first mixture stream outlet; the first liquid phase material outlet of the first gas-liquid separator 8 is connected to the first liquid phase 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 mixture stream 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 mixture stream 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 mixture stream outlet of the second mixer 6B is connected to the second mixture stream inlet of the second gas-liquid separator 9;

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

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

[0182] 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 connected to the secondary dilution steam inlets of the second mixer 6B and the second mixer 6C, respectively; 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 connected to the first pipeline and the third liquid phase material inlet of the second mixer 6B respectively.

[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 includes: 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 radiant 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. The radiant 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 a first pipeline, on which a first mixer 6A is provided. The heating inlet of the third heating section 3A is connected to a primary steam source, and 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 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. The heating inlet of the fifth heating section 3B is connected to a 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, 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. 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, 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 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 steam cracking heavy hydrocarbons to produce olefins includes:

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

[0191] S2. Mix at least a portion of the first liquid-phase material with the primary dilution steam superheated in the third heating section 3A in a first mixer 6A, superheat or vaporize the mixture to obtain a first mixed flow. The first mixed flow enters the fourth heating section 4 for first heating, and then is mixed with at least a portion of the secondary dilution steam in a third mixer 6C, superheat or vaporize the mixture to obtain a third mixed flow. The third mixed flow enters 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 after being superheated by the fifth heating section 3B in the second mixer 6B to be superheated or gasified, to obtain a second mixture flow;

[0194] The second mixture flow is introduced into the second gas-liquid separator 9 to be in contact with the third mixture flow to be second separated, to obtain a second gas phase material and a second liquid phase material; meanwhile, a cooling aid is introduced into the gas phase space of the second gas-liquid separator 9 to control the tube wall temperature of the second gas-liquid separator 9 to prevent coking in the re-gasification process; the cooling aid is cooling water;

[0195] S3, the second gas phase material enters the sixth heating section 5 to be second heated and then enters the radiant section of the steam cracking device to be steam cracked, to obtain a cracking product containing olefins; the second liquid phase material enters a post-treatment device.

[0196] As shown in Figure 2 , an exemplary embodiment of the system for producing olefins by steam cracking of heavy hydrocarbons provided by the present disclosure is different from the system shown in Figure 1 in that: the system is not provided with a separator 7; the outlets of the first gas phase material are respectively connected to the first pipeline and the first gas phase material inlet of the second mixer 6B.

[0197] The method step S2 comprises: mixing the first liquid phase material, at least part of the first gas phase material, and the primary dilution steam after being superheated to obtain a first mixture flow;

[0198] Mixing at least part of the first gas phase material with the secondary dilution steam after being superheated in the second mixer 6B to be superheated or gasified to obtain a second mixture flow, and introducing the second mixture flow into the second gas-liquid separator 9; introducing the second mixture flow into the second gas-liquid separator 9 to be in contact with the third mixture flow to be second separated, to obtain a second gas phase material and a second liquid phase material.

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

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

[0201] The steam cracking device comprises a convection section and a radiant section; along the height direction of the steam cracking device, the convection section is sequentially provided from top to bottom with the first heating section 1A, the boiler feed water preheating section BFW, the third heating section 3A, the fourth heating section 4, the fifth heating section 3B, and the sixth heating section 5; the radiant section comprises 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 material flow inlet, a second mixed material flow inlet, a second gas-phase material outlet and a second liquid-phase material outlet;

[0203] The heating inlet of the first heating section 1A is used for introducing the heavy hydrocarbon to be preheated; the heating outlet of the first heating section 1A is communicated with 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 communicated with the heating inlet of the fourth heating section 4 via a first pipeline; the heating inlet of the third heating section 3A is communicated with a 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 communicated with the third mixed material flow inlet of the second gas-liquid separator 9, and a third mixer 6C is arranged on the communication pipeline;

[0204] The first gas-phase material outlet of the first gas-liquid separator 8 is communicated with the first gas-phase material inlet of the second mixer 6B via a second pipeline; the first gas-phase material outlet of the first gas-liquid separator 8 is communicated with the first gas-phase material inlet of the second mixer 6B and a post-treatment device respectively; the heating inlet of the fifth heating section 3B is communicated with a secondary steam source, and the heating outlet of the fifth heating section 3B is 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 respectively; the second mixed material flow outlet of the second mixer 6B is communicated with the second mixed material flow inlet of the second gas-liquid separator 9; the second gas-phase material outlet of the second gas-liquid separator 9 is communicated with the heating inlet of the sixth heating section 5, and the heating outlet of the sixth heating section 5 is communicated with the radiant section of the steam cracking device; the second liquid-phase material outlet of the second gas-liquid separator 9 is communicated with the post-treatment device;

[0205] The system shown in the figure is used to carry out the specific process flow of producing olefins by steam cracking of heavy hydrocarbons, which comprises: Figure 3

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

[0207] S2, at least part of the first liquid-phase material is mixed with the primary dilution steam overheated by the third heating section 3A in the first mixer 6A to obtain a first mixed material flow; the first mixed material flow enters the fourth heating section 4 for first heating and is mixed with the secondary dilution steam overheated by the fifth heating section 3B to obtain a third mixed material flow;

[0208] ​mixing the at least part of the first gas phase material with the secondary dilution steam after being superheated by the fifth heating section 3B in the second mixer 6B to obtain a second mixture stream; and mixing another part of the first gas phase material into the post-treatment device;

[0209] mixing the third mixture stream and the second mixture stream into the second gas-liquid separator 9 to obtain a second gas phase material and a second liquid phase material;

[0210] S3, making the second gas phase material enter the sixth heating section 5 to be second heated and then enter the radiant section of the steam cracking device to be steam cracked to obtain a cracking product containing olefins; and making the second liquid phase material enter the post-treatment device.

[0211] The present disclosure will be further illustrated by examples, but the present disclosure is not limited in any way by the examples.

[0212] Example 1

[0213] The flow of this example refers to Figure 1 , and a heavy hydrocarbon with an API value of 44 is used, which specifically includes the following steps:

[0214] S1, making the heavy hydrocarbon from the storage tank enter the first heating section 1A of the convection section of the steam cracking device after being preliminarily preheated to be first preheated, and the temperature of the first preheated heavy hydrocarbon is 112℃; and sending the first preheated heavy hydrocarbon into the second heating section 1B to obtain a second preheated heavy hydrocarbon, and the temperature of the second preheated heavy hydrocarbon is 269℃, and the vaporization rate is 26%;

[0215] making the second preheated heavy hydrocarbon enter the first gas-liquid separator 8 to be first separated as a preheated heavy hydrocarbon to obtain a first gas phase material and a first liquid phase material; the first gas phase material contains a first light component, and the mass fraction is 35wt%; and the first liquid phase material contains a first heavy component, and the mass fraction is 65wt%;

[0216] S2, mixing the first liquid phase material and the primary dilution steam after being superheated by the third heating section 3A in the first mixer 6A to be superheated and vaporized to obtain a first mixture stream; 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℃, and the temperature of the first mixture stream is 259℃;

[0217] The first mixture stream is sent to the fourth heating section 4 for first heating, and the temperature of the first mixture stream after the first heating is 320℃; the first mixture stream after the first heating is mixed with the secondary dilution steam after the superheating of the fifth heating section 3B in the third mixer 6C for superheating and vaporization to obtain a third mixture stream, and the third mixture stream is sent to 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℃, the temperature of the third mixture stream is 318℃, and the vaporization rate is 59%;

[0218] The first gas phase material is sent to the separation tower 7 for third separation to obtain a third gas phase material (the final boiling point temperature is 165℃) and a third liquid phase material (the initial boiling point temperature is ≥165℃); 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 superheated secondary dilution steam after the fifth heating section 3B in the second mixer 6B for vaporization and superheating to obtain a second mixture stream, 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 mixture stream is 453℃, and the second mixture stream is introduced into the lower part of the second gas-liquid separator 9, while cooling water is introduced into the second gas-liquid separator 9, and the temperature in the second gas-liquid separator 9 is controlled to be 290-400℃;

[0219] The third mixture stream and the second mixture stream are mixed in the second gas-liquid separator 9 for second separation to obtain a second gas phase material and a second liquid phase material; the second gas phase material contains carried steam and a second light component, and the second liquid phase material contains a second heavy component (the initial boiling point temperature is 430℃, the flash point temperature of the second liquid phase material is controlled to be higher than 116℃, and the tank storage requirement is met); wherein the superheated second mixture stream is used for stripping the third mixture stream, so that the impurities carried in the separated second gas phase material are washed or condensed;

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

[0221] Example 2

[0222] The flow of this example is shown in Figure 2 , and the heavy hydrocarbon with an API value of 38 is used, which specifically includes the following steps:

[0223] S1, the heavy hydrocarbon from the storage tank is first preheated and then passed through the first heating section 1A of the convection section of the steam cracking device for first preheating, the first preheated heavy hydrocarbon has a temperature of 115°C; the first preheated heavy hydrocarbon is sent to the second heating section 1B to obtain second preheated heavy hydrocarbon, the second preheated heavy hydrocarbon has a temperature of 235°C, and the gasification rate of the second preheated heavy hydrocarbon is 21%;

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

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

[0226] The first mixed stream is sent to the fourth heating section 4 for first heating, and the first heated first mixed stream has a temperature of 248°C; the first heated first mixed stream is mixed with the overheated secondary dilution steam passing through the fifth heating section 3B in the third mixer 6C to obtain a third mixed stream, and the third mixed stream is sent to the second gas-liquid separator 9; the weight ratio of the first liquid phase material to the overheated secondary dilution steam is 1:0.14; the temperature of the overheated secondary dilution steam is 418°C, the temperature of the third mixed stream is 232°C, and the gasification rate is 41%;

[0227] At least part of the first gas phase material is mixed with the overheated secondary dilution steam passing through the fifth heating section 3B in the second mixer 6A to obtain a second mixed stream, the temperature of the second mixed stream is 395°C, and the second mixed stream is introduced from 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 overheated secondary dilution steam is 1:0.50; the weight ratio of the first gas phase material in the second mixed stream to the first gas phase material in the first mixed stream is 1:2.70.

[0228] The third mixture stream and the second mixture stream are mixed 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 a second heavy component (with an initial boiling point of 414℃) ;

[0229] S3, the second gas phase material is subjected to a second heating in the sixth heating section 5 and then enters the radiant section of the steam cracking device to be subjected to steam cracking, wherein the steam cracking temperature is 800℃, the residence time of the radiant furnace tube is 0.24s, and the second liquid phase material separated by the second gas-liquid separator 9 is sent to the oil refining device.

[0230] Example 3

[0231] The flowchart of this example is shown in Figure 3 , and the heavy hydrocarbon with an API value of 38 is used, and the specific steps include the following steps:

[0232] S1, the heavy hydrocarbon from the storage tank is subjected to a first preheating after a preliminary preheating and then subjected to a first preheating in the first heating section 1A of the convection section of the steam cracking device, wherein the temperature of the first preheated heavy hydrocarbon is 229℃, and the gasification rate of the first preheated heavy hydrocarbon is 20%;

[0233] The first preheated heavy hydrocarbon is used as the preheated heavy hydrocarbon to be subjected to a first separation in the first gas-liquid separator 8 to obtain a first gas phase material and a first liquid phase material, wherein the first gas phase material contains a first light component with a mass fraction of 26wt%; and the first liquid phase material contains a first heavy component with a mass fraction of 74wt%;

[0234] S2, the first liquid phase material is mixed with the once-diluted steam subjected to a superheating in the third heating section 3A in the first mixer 6A to obtain a first mixture stream, wherein the weight ratio of the first liquid phase material to the once-diluted steam subjected to a superheating is 1:0.21; the temperature of the once-diluted steam subjected to a superheating is 374℃, and the temperature of the first mixture stream is 334℃;

[0235] The first mixed stream enters the fourth heating section 4 for a first heating, and is then mixed with the secondary dilution steam superheated in the fifth heating section 3B in the third mixer 6C, superheated, and vaporized to obtain a third mixed stream. The third mixed stream enters the second gas-liquid separator 9, and the temperature of the first mixed stream after the first heating is 389° C. At least a portion of the first gas-phase material and the secondary dilution steam superheated in the fifth heating section 3B are second-mixed, vaporized, and superheated in the second mixer 6B to obtain a second mixed stream, and the temperature of the second mixed stream is 313° C. The second mixed stream is introduced through the lower portion 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 stream is 378° C., and the vaporization 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 boiling point temperature is 402°C);

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

[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 superheated secondary dilution steam is 1:0.17; the temperature of the superheated secondary dilution steam is 398° C.;

[0244] The second gas phase material contains entrained steam and second light components, the second liquid phase material contains second heavy components with a first distillation point of 348℃, and the second heavy components contain more of the second light components;

[0245] The steam cracking temperature is 781℃, and the radiant furnace tube residence time is 0.23s.

[0246] By the above technical solution, the method for producing olefins by steam cracking of 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 use heavy hydrocarbons directly for cracking to produce olefins, greatly reducing the production devices for heavy hydrocarbon pretreatment provided in the traditional heavy hydrocarbon device, and producing olefins with the shortest process and minimum energy consumption.

[0247] The preferred embodiments of the present disclosure are described in detail above in combination with the drawings, but the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept range of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all belong to the protection range of the present disclosure.

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

[0249] In addition, various different embodiments of the present disclosure can also be combined in any manner as long as they do not deviate from the idea of the present disclosure, and they should also be considered as disclosed by the present disclosure.

Claims

1. A process for steam cracking of heavy hydrocarbons, characterized in that, The method comprises the following steps: 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; S2. mixing at least a portion of the first liquid-phase material with primary dilution steam to obtain a first mixed flow, heating the first mixed flow, and then mixing the first mixed flow with at least a portion of secondary dilution steam to obtain a third mixed flow; mixing at least a portion of the first gaseous material with at least a portion of the secondary dilution steam to produce a second mixed stream; The third mixed flow and the second mixed flow 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 radiant section of a steam cracking device for steam cracking to obtain a cracking product containing olefins; Wherein, step S2 also includes: allowing at least a portion 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; 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); At least a portion 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.

2. The method of claim 1, wherein, In step S1, the temperature of the preheated heavy hydrocarbon is 200-400°C; The first gas phase material comprises a first light component, and the first liquid phase material comprises a first heavy component; The gasification rate of the preheated heavy hydrocarbons is 20-65%.

3. The method of claim 2, wherein, In step S1, the temperature of the preheated heavy hydrocarbon is 240-370°C; The gasification rate of the preheated heavy hydrocarbons is 25-45%.

4. The method of claim 1, wherein, The weight ratio of the first liquid phase material to the primary dilution steam is 1:(0.1-0.5); The weight ratio of the first liquid phase material to the secondary dilution steam is 1:(0-0.55); 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 subjecting the superheated primary dilution steam, the first liquid-phase material, and at least a portion of the first gas-phase material to a first mixing process 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; The first mixed flow enters a 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; The temperature of the superheated primary dilution steam is 240-400°C; The temperature of the first mixed stream is 200-350°C; The temperature of the first mixed stream after the first heating is below 400° C. The temperature of the superheated secondary dilution steam is 400-630°C; 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).

5. The method of claim 4, wherein, The weight ratio of the first liquid phase material to the primary dilution steam is 1:(0.15-0.4); The weight ratio of the first liquid phase material to the secondary dilution steam is 1:(0.10-0.35); The temperature of the superheated primary dilution steam is 280-385℃; The temperature of the first mixture stream is 240-300℃; The temperature of the first mixture stream after the first heating is 285-370℃; The temperature of the superheated secondary dilution steam is 450-595℃; The weight ratio of the first gas phase material in the second mixture stream to the first gas phase material in the first mixture stream is 1:(2.35-153).

6. The method of claim 1, wherein, The second gas phase material contains steam and second light components; the second liquid phase material contains second heavy components; the end boiling point temperature of the second light components is 330-500℃; the second gas phase material contains no more than 1wt% of heavy components with carbon atom number not less than 30; The step S2 further comprises: Mixing at least part of the first liquid phase material, at least part of the third liquid phase material and the primary dilution steam in a first mixer (6A) to obtain a first mixture stream; The weight ratio of the first liquid phase material to the primary dilution steam in the first mixture stream is 1:(0.1-0.5); Mixing at least part of the secondary dilution steam and the first mixture stream in a third mixer (6C) to obtain a third mixture stream; Mixing at least part of the first gas phase material and the secondary dilution steam in a second mixer (6B) to obtain a second mixture stream; or mixing at least part of the third liquid phase material and the secondary dilution steam in a second mixer (6B) to obtain a second mixture stream; the weight ratio of the third liquid phase material in the second mixture stream to the third liquid phase material in the first mixture stream is 1:(2-154); The temperature of the second mixture stream is 300-550℃; The temperature of the third mixture stream is 200-450℃; Introducing a cooling aid into the gas phase space of the second gas-liquid separator (9), the cooling aid comprising water and / or liquid hydrocarbon, the liquid hydrocarbon comprising diesel fraction; Introducing at least part of the third liquid phase material into the gas phase space of the second gas-liquid separator (9) as the cooling aid; The first mixture stream and the cooling aid are introduced into the gas phase space of the second gas-liquid separator (9) in different directions; 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); The method further comprises: sending at least part of the first gas phase material out for post-treatment, the post-treatment comprising one or more of reforming treatment, normal-isomer separation, and not including steam cracking.

7. The method of claim 6, wherein, The second gas phase material contains no more than 0.5wt% of heavy components with carbon atom number not less than 30; The weight ratio of the first liquid phase material to the primary dilution steam in the first mixture stream is 1:(0.15-0.4); The weight ratio of the third liquid phase material in the second mixture stream to the third liquid phase material in the first mixture stream is 1:(3.5-153); The temperature of the second mixture stream is 325-500℃, and the temperature of the third mixture stream is 285-400℃; The cooling aid is introduced into the gas phase space of the second gas-liquid separator (9) above the first mixture stream to cool the gas phase components in the first mixture stream; The weight ratio of the first gas phase material or the third liquid phase material to the secondary dilution steam is 1:(0.6-3.5).

8. The method of 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 comprises at least 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); Step S1 further comprises: The heavy hydrocarbon to be preheated enters the first heating section (1A) for first preheating to obtain first preheated heavy hydrocarbon; and then the first preheated heavy hydrocarbon enters the first gas-liquid separator (8) as the preheated heavy hydrocarbon; At least part of the first preheated heavy hydrocarbon from the first heating section (1A) enters the second heating section (1B) for heating to obtain second preheated heavy hydrocarbon; and then the second preheated heavy hydrocarbon enters the first gas-liquid separator (8) as the preheated heavy hydrocarbon; The first preheated heavy hydrocarbon is heated after desalination treatment, or the heavy hydrocarbon to be preheated is first preheated after desalination treatment.

9. A system for steam cracking of heavy hydrocarbons, the system being for carrying out the method of claim 1, 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 separate the preheated heavy hydrocarbon to obtain a first gas phase material and a first liquid phase material; The second gas-liquid separator (9) is configured to separate a third mixture stream and a second mixture stream to obtain a second gas phase material and a second liquid phase material; The radiation section of the steam cracking device is configured to perform steam cracking on at least part of the second gas phase material to obtain a cracking product comprising olefins; The system further comprises a post-treatment device configured to post-treat at least part of the first gas phase material.

10. The system of claim 9, wherein, The convection section is provided with a raw material heating inlet and a raw material heating outlet; and 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 in communication with the raw material heating outlet of the convection section; and the first liquid phase material outlet of the first gas-liquid separator (8) is in communication with the steam cracking inlet of the radiation section; The second gas-liquid separator (9) is provided with a third mixture stream inlet, a second mixture stream inlet, an optional cooling aid inlet, a second gas phase material outlet and a second liquid phase material outlet; The cooling aid inlet comprises a liquid hydrocarbon inlet and / or a water inlet; The third mixture flow inlet of the second gas-liquid separator (9) is communicated with the heating outlet of the fourth heating section (4); the first gas phase material outlet of the first gas-liquid separator (8) is communicated with the second mixture flow inlet of the second gas-liquid separator (9) via a second pipeline; The radiant section comprises a steam cracking inlet and a cracking product outlet; the second gas phase material outlet of the second gas-liquid separator (9) is communicated with the steam cracking inlet of the radiant section.

11. The system of claim 10, wherein, Along the height direction of the steam cracking device, the convection section comprises at least 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); The heating inlet of the first heating section (1A) is used for introducing the heavy hydrocarbon to be preheated; the heating outlet of the first heating section (1A) is communicated with the gas-liquid separation inlet of the first gas-liquid separator (8); a pressure regulating valve is arranged on the introduction pipeline of the gas-liquid separation inlet of the first gas-liquid separator (8) to control the preheating temperature of the heavy hydrocarbon entering the first gas-liquid separator (8); a pressure regulating valve is arranged on the leading-out pipeline of the first gas phase material outlet to further control the gasification rate; The heating inlet of the fourth heating section (4) is communicated with the first liquid phase material outlet of the first gas-liquid separator (8) via a first pipeline; the heating inlet of the third heating section (3A) is communicated with 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 communicated with the third mixture flow inlet of the second gas-liquid separator (9); the heating inlet of the fifth heating section (3B) is communicated with a secondary steam source; the heating outlet of the fifth heating section (3B) is respectively connected to the communication pipeline of the heating outlet of the fourth heating section (4) and the third mixture flow inlet of the second gas-liquid separator (9) and the second pipeline; The heating inlet of the sixth heating section (5) is communicated with the second gas phase material outlet of the second gas-liquid separator (9); the heating outlet of the sixth heating section (5) is communicated with the steam cracking inlet of the radiant section; The second liquid phase material outlet of the second gas-liquid separator (9) can be used to communicate with a hydrocracking or catalytic cracking device; At least one of a cooler, a tray and a hydrocyclone is arranged inside the second gas-liquid separator (9); 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 communicated with the first gas phase material inlet of the separation tower (7); the third liquid phase material outlet of the separation tower (7) is communicated with the second mixture 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-treatment device.

12. The system of claim 11, wherein, The first pipeline is provided with a first mixer (6A) for mixing and superheating or gasifying the first liquid phase material and the primary dilution steam to obtain a first mixed material flow; The second pipeline is provided with a second mixer (6B) for mixing and superheating or gasifying the first gas phase material and the secondary dilution steam to obtain a second mixed material flow; The heating outlet of the fourth heating section (4) is further provided with a third mixer (6C) in the communication pipeline with the third mixed material flow inlet of the second gas-liquid separator (9) for mixing and superheating or gasifying the first mixed material flow and at least part of the secondary dilution steam to obtain a third mixed material flow; The first mixer (6A) is provided with a first liquid phase material inlet, a primary dilution steam inlet and a first mixed material flow outlet; the first liquid phase material outlet of the first gas-liquid separator (8) is communicated with the first liquid phase material inlet of the first mixer (6A), and the heating outlet of the third heating section (3A) is communicated with the primary dilution steam inlet of the first mixer (6A); the first mixed material flow outlet of the first mixer (6A) is communicated with 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 material flow outlet; the first gas phase material outlet of the first gas-liquid separator (8) is communicated with the first gas phase material inlet of the second mixer (6B), and the second mixed material flow outlet of the second mixer (6B) is communicated with the second mixed material flow inlet of the second gas-liquid separator (9); The third mixer (6C) is provided with a first mixed material flow inlet, a secondary dilution steam inlet and a third mixed material flow outlet; the heating outlet of the fourth heating section (4) is communicated with the first mixed material flow inlet of the third mixer (6C), the heating outlet of the fifth heating section (3B) is respectively communicated with 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 material flow outlet of the third mixer (6C) is communicated with the third mixed material flow inlet of the second gas-liquid separator (9); 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); Alternatively, the second mixer (6B) is arranged on the third pipeline for mixing the third liquid phase material with the secondary dilution steam therein to superheat or vaporize the third liquid phase material to obtain a second mixture stream; the second mixer (6B) is provided with a third liquid phase material inlet, a secondary dilution steam inlet and a second mixture stream outlet; the third liquid phase material outlet of the separation tower (7) is in communication with the third liquid phase material inlet of the second mixer (6B), the heating outlet of the fifth heating section (3B) is in communication with the secondary dilution steam inlet of the second mixer (6B) and the secondary dilution steam inlet of the third mixer (6C) respectively, and the second mixture stream outlet of the second mixer (6B) is in communication with the second mixture stream inlet of the second gas-liquid separator (9); the heating outlet of the first heating section (1A) is in communication with the heating inlet of the second heating section (1B); and the heating outlet of the second heating section (1B) is in communication with the gas-liquid separation inlet of the first gas-liquid separator (8); 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.

Images