A system and method for separating a crude oil to olefin reaction product

Abstract

The application relates to a crude oil olefin reaction product separation system and a separation method, and belongs to the technical field of petroleum chemical industry. The crude oil olefin reaction product separation system comprises a fractionating tower, a desorption tower, a stabilizing tower, a demethanizing tower, a front depropanizing tower, a rear depropanizing tower, a deethanizing tower, an ethylene rectifying tower and a propylene rectifying tower. The reaction product of the crude oil olefin can be effectively separated without adopting cryogenic separation, oil slurry, light diesel oil, mixed carbon four, gasoline, ethane and propane are obtained, polymerization-grade ethylene and polymerization-grade propylene can be obtained, and reasonable conversion and utilization of the reaction product are realized.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical technology, and specifically relates to a separation system and method for the products of crude oil to olefins reaction. Background Technology

[0002] Direct crude oil to low-carbon olefins (LNO) technology has become an important direction for the transformation and development of the refining and chemical industry. Its feedstock is crude oil, not naphtha, light diesel, or hydrotreated tail oil, eliminating the need for fractionation and hydrotreating units. Its products are mainly LNO and aromatics, with extremely low gasoline and diesel yields. Using traditional processes, fuel-based enterprises achieve a LNO yield of approximately 8%, while integrated refining and chemical enterprises achieve 14-20%. However, with direct crude oil to LNO technology, the yield can reach over 40%, creating economies of scale and cost advantages, resulting in strong market competitiveness and significant economic benefits.

[0003] Compared to traditional catalytic cracking units, the yields of products from crude oil direct to olefins (CTO) show significant changes, with a substantial increase in dry gas and LPG yields and a significant decrease in gasoline and diesel yields. Taking heavy oil catalytic cracking as an example, the dry gas + LPG yield is generally <20%, while the dry gas + LPG yield from CTO is >60%. Simultaneously, the CTO products contain high levels of easily coking components such as alkynes and dienes, which readily coke at high temperatures. Traditional catalytic cracking fractionation absorption stabilization processes cannot avoid the high-temperature environment of easily coking components like alkynes and dienes, and cannot separate ethylene, making them unsuitable for CTO product separation. Conventional olefin separation processes generally employ cryogenic separation, requiring complex ethylene refrigeration compressor systems and cold box equipment, resulting in high investment and energy consumption. Therefore, it is necessary to develop a separation system that is simple in process, reliable in operation, and low in energy consumption, taking into account the distribution and composition characteristics of CTO products. Summary of the Invention

[0004] The purpose of this application is to provide a separation system for crude oil to olefins reaction products, which solves the problem that existing technologies cannot effectively separate crude oil to olefins reaction products.

[0005] This invention provides a separation system for the products of a crude oil-to-olefins reaction, comprising: a fractionating tower, wherein the fractionating tower has an oil slurry outlet at its bottom and a light diesel oil outlet in its body; a first oil-gas separator is connected to the top of the fractionating tower, and the gas phase outlet of the first oil-gas separator is connected to a second oil-gas separator via a first gas compressor; a desorption tower, wherein the liquid phase outlet of the first oil-gas separator is connected to the desorption tower, and the top of the desorption tower is connected to the second oil-gas separator; a stabilizing tower, wherein the bottom of the desorption tower is connected to the stabilizing tower, the top of the stabilizing tower has a first C4 outlet, and the bottom of the stabilizing tower has a gasoline outlet; and a demethanizing tower, wherein the gas phase outlet of the second oil-gas separator is connected to the demethanizing tower via a second gas compressor. The demethanizer has a dry gas outlet at its top; a pre-propane demethanizer has its bottom connected to the pre-propane demethanizer; a post-propane demethanizer has its bottom connected to the post-propane demethanizer, and its bottom has a second C4 outlet; an ethane demethanizer has its top and its post-propane demethanizer both connected to the ethane demethanizer; an ethylene distillation tower has its top connected to the ethylene distillation tower, and its top has a polymerization-grade ethylene outlet, while its bottom has an ethane outlet; and a propylene distillation tower has its bottom connected to the propylene distillation tower, and its top has a polymerization-grade propylene outlet, while its bottom has a propane outlet.

[0006] Optionally, the liquid phase outlet of the first oil-gas separator is connected to the fractionation tower via a diversion pipe.

[0007] Optionally, the liquid phase outlet of the second oil-gas separator is connected to the desorption tower.

[0008] Optionally, the second C4 outlet flows in parallel with the first C4 outlet via a parallel flow pipe.

[0009] Optionally, the second C4 outlet is connected to the demethanizer via a splitter.

[0010] Optionally, the first air compressor outlet is provided with a first cooler, the second air compressor outlet is provided with a second cooler, the top of the pre-propane stripper is provided with a third cooler, and the top of the post-propane stripper is provided with a fourth cooler.

[0011] Optionally, a reboiler is provided at the bottom of the demethanizer.

[0012] Optionally, the dry gas outlet is equipped with a desulfurization device.

[0013] This invention also provides a method for separating products from crude oil-to-olefins reaction, applicable to the separation system for crude oil-to-olefins reaction products described in any of the above embodiments, comprising the following steps:

[0014] The products of the crude oil-to-olefins reaction were obtained;

[0015] The reaction products were fractionated to obtain slurry oil, light diesel oil, and mixed gas.

[0016] The mixed gas is cooled to a first temperature, and then subjected to a first oil-gas separation to obtain a first gas phase and a first liquid phase;

[0017] The first gas phase is pressurized to a first gas pressure, and then separated into a second gas phase and a second liquid phase by a second oil-gas separation process.

[0018] The first liquid phase is desorbed to obtain a third gas phase and a third liquid phase;

[0019] The third liquid phase is fractionated to obtain a first mixture of C4 and gasoline;

[0020] The second and third gas phases are pressurized to a second gas pressure, then dehydrated and cooled to a second temperature to obtain the raw material gas;

[0021] The raw gas is subjected to mixed C4 absorption to obtain dry gas and a fourth liquid phase;

[0022] The fourth liquid phase is subjected to a first fractionation to obtain a fifth gas phase and a fifth liquid phase;

[0023] The fifth liquid phase is subjected to a second fractionation to obtain a sixth gas phase and a second mixed C4 phase;

[0024] The fifth and sixth gas phases are cooled to a third temperature and then fractionated to obtain a seventh gas phase and a seventh liquid phase.

[0025] The seventh gas phase was then distilled to obtain polymer-grade ethylene and ethane;

[0026] The seventh liquid phase was distilled to obtain polymer-grade propylene and propane;

[0027] in:

[0028] The first temperature is 40°C;

[0029] The first air pressure is 0.1-0.4 MPa;

[0030] The second air pressure is 2.0-4.0 MPa;

[0031] The second temperature is -20℃;

[0032] The third temperature is -20℃;

[0033] The pressure difference between the desorption pressure and the pressure of the second oil-gas separation is 10-80 kPa;

[0034] The bottom temperature of the desorption column is <80℃, the bottom temperature of the first fractionation column is <80℃, and the bottom temperature of the second fractionation column is <80℃.

[0035] The cooling temperatures are all greater than -35°C.

[0036] Optionally, the following steps may also be included:

[0037] The second mixed C4 solution is split to obtain an absorbent and a product solution;

[0038] The absorbent is used for the mixed C4 absorption.

[0039] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0040] This invention provides a separation system for crude oil-to-olefins reaction products. This system utilizes a fractionation tower, desorption tower, stabilization tower, demethanizer, pre-propane de-propanizer, post-propane de-ethane de-ethane tower, ethylene distillation tower, and propylene distillation tower to perform multi-stage fractionation of the crude oil-to-olefins reaction products. It effectively separates the reaction products without the need for cryogenic separation, yielding slurry oil, light diesel oil, mixed C4 hydrocarbons, gasoline, ethane, and propane. Furthermore, it can produce polymer-grade ethylene and polymer-grade propylene, achieving the rational conversion and utilization of the reaction products.

[0041] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the separation system for crude oil to olefins reaction products provided in an embodiment of the present invention;

[0044] Figure 2 This is a flowchart of a method for separating products from crude oil-to-olefins reaction provided in an embodiment of the present invention.

[0045] Reference numerals: T1 - Fractionating tower; 11 - Slurry outlet; 12 - Light diesel oil outlet; 13 - First cooler; 14 - Second cooler; K1 - First oil-gas separator; C1 - First gas compressor; K2 - Second oil-gas separator; T2 - Desorption tower; T3 - Stabilizer tower; 31 - First C4 outlet; 32 - Gasoline outlet; T4 - Methanogen removal tower; 41 - Dry gas outlet; 42 - Reboiler; 43 - Desulfurization unit; C2 - Second gas compressor; T5 - Pre-propane removal tower; 51 - Third cooler; T6 - Post-propane removal tower; 61 - Second C4 outlet; 62 - Fourth cooler; T7 - ​​Ethane removal tower; T8 - Ethylene distillation tower; 81 - Polymer-grade ethylene outlet; 82 - Ethane outlet; T9 - Propylene distillation tower; 91 - Polymer-grade propylene outlet; 92 - Propane outlet. Detailed Implementation

[0046] The present invention will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present invention more clearly apparent. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present invention.

[0047] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of any conflict, this specification shall prevail. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of protection of this invention. For example, room temperature may refer to a temperature in the range of 10–35°C.

[0048] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0049] Please refer to Figure 1This embodiment provides a separation system for the products of crude oil to olefins reaction, comprising: a fractionating tower T1, wherein the fractionating tower T1 has an oil slurry outlet 11 at its bottom and a light diesel oil outlet 12 at its body; a first oil-gas separator K1 is connected to the top of the fractionating tower T1, and the gas phase outlet of the first oil-gas separator K1 is connected to a second oil-gas separator K2 via a first gas compressor C1; a desorption tower T2, wherein the liquid phase outlet of the first oil-gas separator K1 is connected to the desorption tower T2, and the top of the desorption tower T2 is connected to the second oil-gas separator K2; a stabilizing tower T3, wherein the bottom of the desorption tower T2 is connected to the stabilizing tower T3, wherein the top of the stabilizing tower T3 has a first C4 outlet 31, and the bottom of the stabilizing tower T3 has a gasoline outlet 32; and a demethanizing tower T4, wherein the gas phase outlet of the second oil-gas separator K2 is connected to the demethanizing tower T4 via a second gas compressor C2. The demethanizer T4 has a dry gas outlet 41 at its top; the pre-propane de-tower T5 is connected to the bottom of the demethanizer T4; the post-propane de-tower T6 is connected to the bottom of the pre-propane de-tower T5 and has a second C4 outlet 61 at its bottom; the ethane de-tower T7 is connected to both the top of the pre-propane de-tower T5 and the post-propane de-tower T6; Ethylene distillation column T8 is connected to the top of the deethanizer T7. The top of the ethylene distillation column T8 has a polymerization-grade ethylene outlet 81, and the bottom of the ethylene distillation column T8 has an ethane outlet 82. Propylene distillation column T9 is connected to the bottom of the deethanizer T7. The top of the propylene distillation column T9 has a polymerization-grade propylene outlet 91, and the bottom of the propylene distillation column T9 has a propane outlet 92.

[0050] The aforementioned separation system for crude oil-to-olefins reaction products, by setting up a fractionation tower T1, a desorption tower T2, a stabilization tower T3, a demethanizer T4, a pre-propane de-solvent T5, a post-propane de-solvent T6, a deethaner T7, an ethylene distillation tower T8, and a propylene distillation tower T9, performs multi-stage fractionation of the crude oil-to-olefins reaction products. It can effectively separate the reaction products without the need for cryogenic separation, obtaining slurry oil, light diesel oil, mixed C4, gasoline, ethane, and propane. Furthermore, it can obtain polymer-grade ethylene and polymer-grade propylene, achieving the rational conversion and utilization of the reaction products. Specifically, by setting up a fractionation tower T1, the reaction products are fractionated into oil slurry, light diesel oil, and a mixed gas, where the mixed gas is a mixture of gasoline, liquefied petroleum gas, and dry gas components; the liquid phase is separated into a first gas phase, a first liquid phase, and an aqueous phase by a first oil-gas separator K1, wherein the aqueous phase is discharged as acidic water; the first gas phase is separated into a second gas phase and a second liquid phase by a second oil-gas separator K2; and the carbon components in the first liquid phase are completely desorbed by a desorption tower T2 to obtain a third gas phase and a third liquid phase; In stabilization tower T3, the third liquid phase is separated from the C4 components and gasoline to obtain the first mixed C4 and stabilized gasoline. In demethanizer tower T4, the second and third gas phases are absorbed by mixed C4 to remove C2 and higher components, yielding dry gas and the fourth liquid phase. The dry gas contains inert gases such as methane, hydrogen, and nitrogen. After desulfurization purification, the dry gas can be used as fuel. A pre-propane descaling tower T5 is installed to perform preliminary separation of the C3 and C4 components in the fourth liquid phase, yielding the fifth gas phase and the fifth liquid phase. The fifth liquid phase includes C3 and C4 components, with some C3 components retained to maintain the bottom temperature of the pre-propane stripper T5 below 80°C and inhibit coking of easily coking components such as alkynes and dienes. The fifth gas phase includes C2 and C3 components. A post-propane stripper T6 is used to separate the C3 and C4 components from the fifth liquid phase. Low-pressure conditions are maintained during the separation process to keep the bottom temperature of the post-propane stripper T6 below 80°C and inhibit coking of easily coking components such as alkynes and dienes, resulting in the sixth gas phase and the fifth gas phase. The mixture consists of two C4 phases, where the sixth gas phase comprises C2 and C3 components. An ethane stripper T7 separates the C2 and C3 components from the fifth and sixth gas phases, yielding a seventh gas phase and a seventh liquid phase, where the seventh gas phase is composed of C2 components and the seventh liquid phase is composed of C3 components. An ethylene distillation column T8 separates the ethane and ethylene components from the seventh gas phase, yielding polymerization-grade ethylene and ethane. A propylene distillation column T9 separates the propane and propylene components from the seventh liquid phase, yielding polymerization-grade propylene and propane.

[0051] Furthermore, the liquid phase outlet of the first oil-gas separator K1 is connected to the fractionation tower T1 via a diversion pipe.

[0052] Furthermore, the liquid phase outlet of the second oil-gas separator K2 is connected to the desorption tower T2.

[0053] Furthermore, the second C4 outlet 61 flows in parallel with the first C4 outlet 31 via a parallel flow pipe.

[0054] Furthermore, the second C4 outlet 61 is connected to the demethanizer T4 via a splitter pipe. This configuration allows a portion of the second C4 to be used as the absorbent in the demethanizer T4, achieving the reuse of the mixed C4.

[0055] Furthermore, the outlet of the first air compressor C1 is equipped with a first cooler 13, the outlet of the second air compressor C2 is equipped with a second cooler 14, the top of the pre-propane stripper T5 is equipped with a third cooler 51, and the top of the post-propane stripper T6 is equipped with a fourth cooler 62. By setting the above-mentioned coolers to control the temperature of the raw materials, overall temperature control is achieved.

[0056] Furthermore, a reboiler 42 is provided at the bottom of the demethanizer T4. By providing the reboiler 42, the methane content of the bottom product of the demethanizer T4 can be controlled.

[0057] Furthermore, the dry gas outlet 41 is equipped with a desulfurization device 43.

[0058] Please refer to Figure 2 This embodiment provides a method for separating products from crude oil-to-olefins reaction, applicable to any of the above-mentioned crude oil-to-olefins reaction product separation systems, including the following steps:

[0059] S1, the product of crude oil to olefins reaction is obtained.

[0060] S2. The reaction products are fractionated to obtain oil slurry, light diesel oil and mixed gas.

[0061] S3. The mixed gas is cooled to a first temperature, and then separated into a first gas phase and a first liquid phase by a first oil-gas separation.

[0062] S4. The first gas phase is pressurized to the first gas pressure, and then separated into a second gas phase and a second liquid phase by the second oil-gas separation.

[0063] S5. The first liquid phase is desorbed to obtain the third gas phase and the third liquid phase.

[0064] S6. The third liquid phase is fractionated to obtain a first mixture of C4 and gasoline.

[0065] S7. Pressurize the second and third gas phases to a second gas pressure, then dehydrate and cool to a second temperature to obtain raw material gas.

[0066] S8. The raw material gas is subjected to mixed C4 absorption to obtain dry gas and a fourth liquid phase.

[0067] S9. The fourth liquid phase is subjected to a first fractionation to obtain a fifth gas phase and a fifth liquid phase.

[0068] S10. The fifth liquid phase is subjected to a second fractionation to obtain a sixth gas phase and a second mixed C4.

[0069] S11. After cooling the fifth and sixth gas phases to the third temperature, fractionate them to obtain the seventh gas phase and the seventh liquid phase.

[0070] S12. The seventh gas phase is distilled to obtain polymer-grade ethylene and ethane.

[0071] S13. The seventh liquid phase is distilled to obtain polymer-grade propylene and propane;

[0072] in:

[0073] The first temperature is 40°C;

[0074] The first air pressure is 0.1-0.4 MPa;

[0075] The second air pressure is 2.0-4.0 MPa;

[0076] The second temperature is -20℃;

[0077] The third temperature is -20℃;

[0078] The pressure difference between the desorption pressure and the pressure of the second oil-gas separation is 10-80 kPa;

[0079] The bottom temperature of the desorption column is <80℃, the bottom temperature of the first fractionation column is <80℃, and the bottom temperature of the second fractionation column is <80℃.

[0080] The cooling temperatures are all greater than -35°C.

[0081] Furthermore, it also includes the following steps:

[0082] S10.1. The second mixed C4 is split to obtain an absorbent and a product liquid;

[0083] S10.2. Use the absorbent liquid for the mixed C4 absorption.

[0084] Example 1

[0085] A method for separating products from crude oil-to-olefins reaction, comprising the following steps:

[0086] S1. The crude oil to olefins reaction product is obtained. The composition of the reaction product is shown in Table 1.

[0087] Component Mass fraction % Mass flow kg / h Dry gas 17.66 20138 Liquefied gas 50.67 57800 Gasoline 21.52 24550 Light diesel 7.63 8700 Slurry oil 2.52 2875 Total 100 114063 Ethylene 11.38 12975 Propylene 28.69 32725

[0088] S2. The reaction products are fractionated using a distillation tower T1 to obtain an oil slurry at the bottom of the tower, a light diesel oil in the middle of the tower, and a mixed gas at the top of the tower.

[0089] S3. The mixed gas is cooled to 40°C using the first cooler 13, and then the first oil-gas separator K1 is used to perform the first oil-gas separation to obtain the first gas phase and the first liquid phase.

[0090] S4. The first gas phase is pressurized to 0.23MPa using the first air compressor C1, and then the second oil-gas separator K2 is used for the second oil-gas separation to obtain the second gas phase and the second liquid phase.

[0091] S5. The first liquid phase is desorbed using desorption tower T2. The bottom temperature of desorption tower T2 is 61℃. The third gas phase is obtained at the top of the tower and the third liquid phase is obtained at the bottom of the tower.

[0092] S6. The third liquid phase is fractionated using a stabilizer tower T3, and the first mixed C4 is obtained from the top of the tower, while gasoline is obtained from the bottom of the tower.

[0093] S7. The second gas phase and the third gas phase are pressurized to 2.8 MPa using the second air compressor C2, then dehydrated, and cooled to -20°C using the second cooler 14 to obtain the raw material gas.

[0094] S8. The feed gas is mixed and absorbed by the demethanizer tower T4. The absorbent dosage is 55000 kg / h. The methane content at the bottom of the tower is controlled to be 0.1% mol by the reboiler 42. Dry gas is obtained at the top of the tower and the fourth liquid phase is obtained at the bottom of the tower.

[0095] S9. The fourth liquid phase is fractionated in the pre-propane desulfurization tower T5. The bottom temperature of the pre-propane desulfurization tower T5 is 75℃. The fifth gas phase is obtained at the top of the tower and the fifth liquid phase is obtained at the bottom of the tower.

[0096] S10. The fifth liquid phase is fractionated in the post-propane desulfurization tower T6. The top pressure of the post-propane desulfurization tower T6 is 0.9 MPa and the bottom temperature is 74 °C. The sixth gas phase is obtained at the top of the tower and the second mixed C4 phase is obtained at the bottom of the tower.

[0097] S10.1. The second mixed C4 is split to obtain an absorbent and a product liquid.

[0098] S10.2 Cool the absorbent to -20°C for use in the mixed C4 absorption.

[0099] S11. The fifth and sixth gas phases are cooled to -20°C using the third cooler 51 and the fourth cooler 62, respectively. Then, the de-ethanizer T7 is used for fractionation to obtain the seventh gas phase at the top of the column and the seventh liquid phase at the bottom of the column.

[0100] S12. The seventh gas phase is distilled using ethylene distillation column T8 to obtain polymer-grade ethylene at the top of the column with an ethylene recovery rate of 99.6% and 1624 kg / h of ethane at the bottom of the column.

[0101] S13. The seventh liquid phase is distilled using propylene distillation column T9 to obtain polymer-grade propylene at the top of the column with a propylene recovery rate of 99.8% and propane at the bottom of the column.

[0102] Finally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0103] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0104] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A separation system for products from the direct crude oil to olefins reaction, characterized in that, include: A fractionation tower (T1) is used to fractionate the reaction products into oil slurry, light diesel oil, and mixed gas. The mixed gas is a mixture of gasoline, liquefied petroleum gas, and dry gas components. The fractionation tower (T1) has an oil slurry outlet (11) at the bottom and a light diesel oil outlet (12) in the body. The top of the fractionation tower (T1) is connected to a first oil-gas separator (K1) to separate the liquid phase into a first gas phase, a first liquid phase, and a water phase. The gas phase outlet of the first oil-gas separator (K1) is connected to a second oil-gas separator (K2) through a first air compressor (C1) to separate the first gas phase into a second gas phase and a second liquid phase. The desorption tower (T2) is used to desorb all the carbon components in the first liquid phase to obtain the third gas phase and the third liquid phase. The liquid phase outlet of the first oil-gas separator (K1) is connected to the desorption tower (T2), and the top of the desorption tower (T2) is connected to the second oil-gas separator (K2). The stabilization tower (T3) is used to separate the third liquid phase from the C4 component and gasoline to obtain the first mixed C4 and stabilized gasoline. The bottom of the desorption tower (T2) is connected to the stabilization tower (T3). The top of the stabilization tower (T3) has a first C4 outlet (31), and the bottom of the stabilization tower (T3) has a gasoline outlet (32). The demethanizer (T4) is used to absorb the second and third gas phases using mixed C4 absorption, absorbing C2 and above components to obtain dry gas and a fourth liquid phase. The gas phase outlet of the second oil-gas separator (K2) is connected to the demethanizer (T4) through the second gas compressor (C2). The demethanizer (T4) has a dry gas outlet (41) at the top. The pre-propane de-coupling tower (T5) is used for the preliminary separation of C3 and C4 components in the fourth liquid phase to obtain the fifth gas phase and the fifth liquid phase. The bottom of the demethanizer tower (T4) is connected to the pre-propane de-coupling tower (T5). The post-propane stripper (T6) is used to separate the fifth liquid phase into C3 and C4. The bottom of the pre-propane stripper (T5) is connected to the post-propane stripper (T6), and the bottom of the post-propane stripper (T6) has a second C4 outlet (61). The ethane stripper (T7) is used to separate C2 and C3 in the fifth and sixth gas phases to obtain the seventh gas phase and the seventh liquid phase. The top of the pre-propane stripper (T5) and the post-propane stripper (T6) are both connected to the ethane stripper (T7). The ethylene distillation column (T8) is used to separate ethane and ethylene in the seventh gas phase to obtain polymer-grade ethylene and ethane. The top of the de-ethanizer (T7) is connected to the ethylene distillation column (T8). The top of the ethylene distillation column (T8) has a polymer-grade ethylene outlet (81), and the bottom of the ethylene distillation column (T8) has an ethane outlet (82). The propylene distillation column (T9) is used to separate propane and propylene from the seventh liquid phase to obtain polymer-grade propylene and propane. The bottom of the deethanizer (T7) is connected to the propylene distillation column (T9). The top of the propylene distillation column (T9) has a polymer-grade propylene outlet (91), and the bottom of the propylene distillation column (T9) has a propane outlet (92). The bottom temperatures of the pre-propane de-coating tower (T5) and the post-propane de-coating tower (T6) are controlled to be below 80°C to suppress coking of alkynes and dienes in the reaction products.

2. The separation system for the products of the direct crude oil to olefins reaction according to claim 1, characterized in that, The liquid phase outlet of the first oil-gas separator (K1) is connected to the fractionation tower (T1) through a diversion pipe.

3. The separation system for the products of the direct crude oil to olefins reaction according to claim 1, characterized in that, The liquid phase outlet of the second oil-gas separator (K2) is connected to the desorption tower (T2).

4. The separation system for the products of the direct crude oil to olefins reaction according to claim 1, characterized in that, The second C4 outlet (61) flows in parallel with the first C4 outlet (31) through a parallel flow pipe.

5. The separation system for the products of the direct crude oil to olefins reaction according to claim 4, characterized in that, The second C4 outlet (61) is connected to the demethanizer (T4) via a splitter pipe.

6. The separation system for the products of the direct crude oil to olefins reaction according to claim 1, characterized in that, The first air compressor (C1) outlet is provided with a first cooler (13), the second air compressor (C2) outlet is provided with a second cooler (14), the top of the pre-propane dehydrogenator (T5) is provided with a third cooler (51), and the top of the post-propane dehydrogenator (T6) is provided with a fourth cooler (62).

7. The separation system for the products of the direct crude oil to olefins reaction according to claim 1, characterized in that, The demethanizer (T4) is equipped with a reboiler (42) at the bottom.

8. The separation system for the products of the direct crude oil to olefins reaction according to claim 1, characterized in that, The dry gas outlet (41) is equipped with a desulfurization device (43).

9. A method for separating products from the direct crude oil to olefins reaction, characterized in that, A separation system applicable to the crude oil direct to olefins reaction products according to any one of claims 1-8, comprising the following steps: The products of the crude oil-to-olefins reaction were obtained; The reaction products were fractionated to obtain slurry oil, light diesel oil, and mixed gas. The mixed gas is cooled to a first temperature, and then subjected to a first oil-gas separation to obtain a first gas phase and a first liquid phase; The first gas phase is pressurized to a first gas pressure, and then separated into a second gas phase and a second liquid phase by a second oil-gas separation process. The first liquid phase is desorbed to obtain a third gas phase and a third liquid phase; The third liquid phase is fractionated to obtain a first mixture of C4 and gasoline; The second and third gas phases are pressurized to a second gas pressure, then dehydrated and cooled to a second temperature to obtain the raw material gas; The raw gas is subjected to mixed C4 absorption to obtain dry gas and a fourth liquid phase; The fourth liquid phase is subjected to a first fractionation to obtain a fifth gas phase and a fifth liquid phase; The fifth liquid phase is subjected to a second fractionation to obtain a sixth gas phase and a second mixed C4 phase; The fifth and sixth gas phases are cooled to a third temperature and then fractionated to obtain a seventh gas phase and a seventh liquid phase. The seventh gas phase was then distilled to obtain polymer-grade ethylene and ethane; The seventh liquid phase was distilled to obtain polymer-grade propylene and propane; The second mixed C4 solution is split to obtain an absorbent and a product solution; The absorbent solution is used for the mixed C4 absorption; in: The first temperature is 40°C; The first air pressure is 0.1-0.4 MPa; The second air pressure is 2.0-4.0 MPa; The second temperature is -20℃; The third temperature is -20℃; The pressure difference between the desorption pressure and the pressure of the second oil-gas separation is 10-80 kPa; The bottom temperature of the desorption column is <80℃, the bottom temperature of the first fractionation column is <80℃, and the bottom temperature of the second fractionation column is <80℃. The cooling temperatures are all greater than -35°C.

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