Synergistic treatment method for aromatic hydrocarbon enrichment and solid removal in oil slurry

Abstract

The present application relates to the field of petroleum processing technology, and particularly relates to a synergistic treatment method for aromatic hydrocarbon enrichment and solid removal in oil slurry, which comprises the following steps: (1) contacting an extractant and catalytic oil slurry to perform extraction, to obtain raffinate phase 1 and extract phase 1, and the mass ratio of the extractant to the catalytic oil slurry is not less than 0.5; (2) removing the extractant and solids from the raffinate phase 1 to obtain raffinate oil, and the removed extractant is returned to step (1) to perform extraction; removing the extractant and solids from the extract phase 1 to obtain aromatic hydrocarbon-enriched desolid oil slurry, and the removed extractant is returned to step (1) to perform extraction. The method can realize the comprehensive effect of deep desolid and aromatic hydrocarbon enrichment in oil slurry, effectively improve the comprehensive utilization value of the oil slurry, avoid the technical problem that part of useful oil slurry components is removed at the same time of removing solid particles, leading to low utilization rate of effective components in the oil slurry, improve the operation cycle of the oil slurry desolid technology, reduce energy consumption, and be beneficial to the technical problem of large-scale industrial application.

Description

Technical Field

[0001] This invention relates to the field of petroleum processing technology, specifically to a synergistic treatment method for aromatic hydrocarbon enrichment and solid removal in oil slurry. Background Technology Catalytic cracking slurry is a byproduct of the catalytic cracking process, containing a large amount of tri- and tetra-cyclic aromatic hydrocarbons, making it an ideal component for the preparation of carbon material precursors. However, solid particles in the slurry, such as catalyst powder, can affect its comprehensive utilization. Therefore, how to effectively remove solid particles from the slurry and improve its comprehensive utilization value is an urgent problem to be solved in the field of petroleum processing technology. The slurry system has high viscosity, especially the polar components such as gums and asphaltenes, which can form "encapsulations" with solid particles through adsorption, increasing the difficulty of solid particle removal. The high ash content (2000-5000 ppm) and wide particle size distribution of solids (0.5-40.0 μm) in the slurry make it very difficult to deeply remove solid particles of all sizes. The existing technology has the following limitations: (1) Insufficient single technology: There is currently no single technology that can effectively remove solid particles with such a wide range of particle sizes; (2) Loss of effective components: When removing solid particles, some useful oil slurry components will be removed along with them, reducing the utilization rate of effective components; (3) Operating cycle and energy consumption issues: The operating cycle is short and the energy consumption is high, which is not conducive to large-scale industrial applications.

[0002] Existing solids removal technologies mainly fall into two categories: intermittent and continuous operation. Intermittent solids removal technology, in terms of its technical principles, primarily involves filtration and sedimentation. Filtration is mainly suitable for situations where the solid particle content in the slurry is not critical, and it can remove solid particles within a certain particle size range, but its removal effect on smaller particles is limited. The removable solid particle size depends on the pore size of the filter medium; generally, it can remove larger particles. Sedimentation can be used for the preliminary separation of solid particles in the slurry, allowing solid particles to settle naturally under gravity, but the sedimentation rate is slow, and the solids removal effect is limited. The removable solid particle size range is: it is more effective for larger particles, but its effect on smaller particles is not significant. To improve the solids removal effect, the industry has developed several enhancement methods, mainly including centrifugation, pressure filtration, electric fields, and magnetic fields during the solids removal process to enhance the solids removal effect. There are also combinations of two or more technologies to improve filtration speed, efficiency, and the range of solid particles removed. Continuous deconsolidation technologies include cross-flow membrane filtration, electric field deconsolidation, and gravity-assisted deconsolidation. However, each has certain limitations. For example, cross-flow membrane filtration inevitably produces 10-20% concentrated oil slurry while obtaining clarified oil slurry, resulting in waste due to a lack of suitable utilization scenarios. Electric field deconsolidation technology has limitations on the polar asphaltenes content in the oil slurry, significantly reducing the operating cycle for oil slurries with high asphaltenes content. Gravity-assisted deconsolidation technology requires the addition of flocculants for better results, but the development of flocculants is also quite difficult, requiring customized development for different types of oil slurries.

[0003] Oil slurry desolidification technology is a key step in improving the comprehensive utilization value of petroleum processing by-products. Currently, although existing technologies have solved the problem of removing solid particles from oil slurry to some extent, many limitations remain. CN115505424A discloses a method for desolidifying catalytic oil slurry, including steps S1: mixing and heating the raw oil slurry with a diluent; step S2: vacuum dehydrating the mixture of raw oil slurry and diluent obtained in step S1; step S3: filtering the mixture obtained in step S2; and step S4: vacuum stripping distillation of the mixture obtained in step S3 to obtain desolidified oil slurry. This invention effectively dissolves a large amount of gum and asphaltenes in the catalytic oil slurry by adding a diluent, destroying the coating layer and interaction forces between the oil slurry and the catalyst powder. Furthermore, the diluent can dilute the catalytic oil slurry and reduce its viscosity, greatly reducing the difficulty of separating the oil and solid phases, effectively achieving desolidification of the catalytic oil slurry, and ensuring further processing of the catalytic oil slurry. This technology introduces new solid particles of clay to adsorb colloids and asphaltenes. After adsorption, these particles form a new encapsulation system, increasing the difficulty of deconsolidation. Subsequent filtration removes the solid particles; however, the specific filtration methods employed are not disclosed, making it impossible to assess the filtration effectiveness. CN111303939A provides a method and system for deconsolidating aromatic oil from catalytic slurry through vacuum distillation to produce needle coke feedstock. This method and system enable comprehensive utilization of the catalytic slurry. High-value aromatic oils are separated by vacuum distillation, and catalyst particles and metallic impurities are efficiently removed using a liquid-solid separator. The clarified oil after solidification has an ash content of no more than 100 ppm, and can even be reduced to below 10 ppm. The aromatic index (BMCI) is no less than 120, and impurities are low (sulfur mass fraction no more than 0.5%, total nitrogen mass fraction no more than 0.05%). All indicators fully meet the requirements for high-quality needle coke feedstock, enabling the regeneration of previously difficult-to-process and low-economic-value catalytic slurry into high-quality oil-based needle coke feedstock. This also lays the foundation for further development of other high-value comprehensive utilization pathways for catalytic slurry, providing a new solution for the disposal of catalytic slurry by petroleum refining enterprises, and significantly improving the economic benefits of related refining and chemical industry chain enterprises. The main problems with this technology are low slurry utilization rate and the inability to truly enrich aromatics due to the close boiling points of aromatics and some saturated hydrocarbons, as boiling point cutting methods cannot achieve true aromatic enrichment.

[0004] The future development direction of oil slurry desolidification technology mainly has three aspects: First, developing new composite technologies that combine different types of desolidification technologies with other oil slurry treatment technologies. Through synergistic effects and optimized process parameters, this can achieve a wider range of solid particle size distributions and greater removal depth. Second, improving the utilization rate of effective components while removing solid particles and minimizing the loss of useful oil slurry components. This can be achieved by further processing the removed solid particles to recover useful components and improve resource utilization. Third, extending the operating cycle and reducing energy consumption. This can be achieved by optimizing equipment design and operating conditions, leveraging the strengths and mitigating the weaknesses of different technologies, and working synergistically to reduce equipment blockage and wear, thereby extending the operating cycle. Summary of the Invention

[0005] The purpose of this invention is to provide a synergistic treatment method for the enrichment of aromatics and the removal of solids in oil slurry. This method can achieve the combined effect of deep desolidification and aromatic enrichment in oil slurry, effectively improving the comprehensive utilization value of oil slurry. It avoids the technical problem that some useful oil slurry components are also removed while removing solid particles, resulting in low utilization rate of effective components in oil slurry. It also improves the operating cycle of oil slurry desolidification technology, reduces energy consumption, and is beneficial for large-scale industrial applications.

[0006] This invention provides a synergistic treatment method for aromatic enrichment and solid removal in slurry oil. The method includes: (1) contacting an extractant and a catalytic slurry oil for extraction to obtain raffinate phase 1 and extraction phase 1, wherein the mass ratio of the extractant to the catalytic slurry oil is not less than 0.5; (2) after removing solids and extractant from raffinate phase 1, raffinate oil is obtained, and the removed extractant is returned to step (1) for extraction; after removing solids and extractant from extraction phase 1, aromatic enriched solidified slurry oil is obtained, and the removed extractant is returned to step (1) for extraction.

[0007] Compared with existing technologies, the beneficial effects of this technical solution are as follows: 1. Deep Desolidification: This technical solution achieves deep desolidification of solids in oil slurry through a combination of processes. The oil slurry treatment process only removes catalyst powder from the oil slurry without other by-products, thereby improving the comprehensive utilization value of the oil slurry.

[0008] 2. Increase throughput and operating cycle: Adding an extraction process before desolidification can remove fine particles that affect the long-term operation of filtration technologies, including cross-flow membrane filtration technology, thereby increasing the throughput of the unit filtration area, saving energy and reducing consumption, and extending the operating cycle of the desolidification unit.

[0009] 3. Optimize equipment usage: For cross-flow membrane filtration units, since the overall solid content is reduced and the catalyst particles are all relatively large, large-flux membrane tubes with larger pore sizes can be used to increase the clarified oil slurry utilization rate and reduce the circulation volume and the proportion of concentrated oil slurry. Furthermore, the membrane flux shows a smaller downward trend during operation, extending the membrane tube's service life.

[0010] 4. Improve product quality: Through the extraction process, aromatic components are enriched, which improves the comprehensive utilization value of the oil slurry. The final refined oil slurry, which is deeply desolidified and enriched with aromatics, can be used as a raw material for the production of needle coke and mesophase pitch.

[0011] 5. Broad Application Prospects: This technical solution can be used to process oil slurry from different sources, and is particularly suitable for processing intermediate-based and paraffin-based oil slurry feedstocks to obtain deeply deconsolidated and aromatic-enriched oil slurry, which can be used to produce high-quality needle coke and mesophase pitch. With the booming development of the carbon materials field using oil slurry as the main raw material, this technology has outstanding technical and economic advantages and very good application prospects. Attached Figure Description

[0012] Figure 1 Flowchart of the subsequent extraction-desolidification combined technology for recovery Figure 2 Flowchart of the extraction-deconsolidation combined technology for recovery Detailed Implementation The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0013] This invention provides a synergistic treatment method for aromatic enrichment and solid removal in slurry oil. The method includes: (1) contacting an extractant and a catalytic slurry oil for extraction to obtain raffinate phase 1 and extraction phase 1, wherein the mass ratio of the extractant to the catalytic slurry oil is not less than 0.5; (2) after removing solids and extractant from raffinate phase 1, raffinate oil is obtained, and the removed extractant is returned to step (1) for extraction; after removing solids and extractant from extraction phase 1, aromatic enriched solidified slurry oil is obtained, and the removed extractant is returned to step (1) for extraction.

[0014] According to a preferred embodiment of the present invention, the mass ratio of the extractant to the catalytic slurry is (0.5-3):1, for example, 1:1, 1.3:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, etc. By employing the aforementioned technical solution, the present invention can achieve both aromatic hydrocarbon enrichment and solid removal from the slurry, while maintaining a low energy consumption during operation.

[0015] In this invention, after extraction, the catalytic oil slurry and the extractant are used to obtain an upper raffinate phase 1 and a lower extractable phase 1. The raffinate phase 1, carrying most of the solid particles, overflows from the top of the extraction device and enters the desolidification device. After sedimentation and desolidification, the raffinate oil overflows from the top of the desolidification device.

[0016] In this invention, the destination of the raffinate oil can be determined according to the different compositions of the saturated components in the slurry. For example, when the saturated components in the slurry are mainly alkanes, the raffinate oil is returned to the catalytic cracking unit for reprocessing after the extractant is removed by stripping distillation or vacuum distillation. When the saturated components in the slurry are mainly cycloalkanes, the raffinate oil is mixed with extraction phase 1 for subsequent processing.

[0017] According to a preferred embodiment of the present invention, when the mass ratio of the extractant to the catalytic slurry is not higher than 1:1, the step of obtaining an aromatic-enriched desolidified slurry after removing solids and extractant from the extraction phase 1 includes: removing solids from the extraction phase 1 to obtain the extraction phase 2, removing the extractant from the extraction phase 2 to obtain the aromatic-enriched desolidified slurry, and returning the extractant removed from the extraction phase 2 to the extraction tower for reuse.

[0018] According to a preferred embodiment of the present invention, when the mass ratio of the extractant to the catalytic slurry is not higher than 1:1, the operating system of the present invention includes: an extraction unit, a desolidification unit A, a desolidification unit B, and a recovery unit. Specifically, the catalytic slurry enters the extraction unit for extraction to obtain raffinate phase 1 and extractable phase 1. Raffinate phase 1 enters the desolidification unit A to obtain upper raffinate oil, lower extractant, and solid-rich components. The lower extractant is returned to the extraction unit for reuse. Extractable phase 1 enters the desolidification unit B for desolidification to obtain extractable phase 2 and solid particles. Extractable phase 2 enters the recovery unit to remove the extractant to obtain an aromatic-enriched and deeply desolidified slurry. The removed extractant is returned to the extraction unit for reuse.

[0019] According to a preferred embodiment of the present invention, when the mass ratio of extractant to catalytic slurry is higher than 1:1, the step of obtaining aromatic-enriched desolidified slurry after removing solids and extractant from extraction phase 1 includes: removing extractant from extraction phase 1 to obtain extraction phase 3, removing solids from extraction phase 3, and then removing extractant to obtain aromatic-enriched desolidified slurry, and returning the extractant removed from extraction phase 1 to the extraction tower for reuse.

[0020] According to a preferred embodiment of the present invention, when the mass ratio of the extractant to the catalytic slurry is higher than 1:1, the operating system of the present invention includes: an extraction unit, a desolidification unit A, a recovery unit A, a desolidification unit B, and a recovery unit B. Specifically, the catalytic slurry enters the extraction unit for extraction to obtain raffinate phase 1 and extractable phase 1. Raffinate phase 1 enters the desolidification unit A for desolidification to obtain upper raffinate oil, lower extractant, and solid-rich components. The lower extractant is returned to the extraction unit for reuse. Extractable phase 1 enters the recovery unit A to remove the extractant to obtain extractable phase 3. The removed extractant is returned to the extraction unit for reuse. Extractable phase 3 enters the desolidification unit B to remove solid particles, and then enters the recovery unit B for further removal of extractant to obtain an aromatic-enriched and deeply desolidified slurry. The removed extractant is returned to the extraction unit for reuse.

[0021] In this invention, after the extraction phase 3 is desolidified, the removed portion concentrates the residual aromatic components containing the extractant in the catalyst powder of the extraction phase 3, which can be returned to the catalytic slurry for re-extraction.

[0022] In this invention, after catalytic oil slurry extraction, the extractant is first removed, resulting in an extractant phase 3 with a viscosity of 1-150 mm. 2 The aforementioned technical solution is more conducive to subsequent detachment.

[0023] In this invention, there are no special limitations on the equipment or apparatus used for the extraction process. For example, it can be carried out in an extraction tower. There are no special requirements for the internal structure of the extraction tower. For example, the extraction tower can have static or dynamic internal components. Static internal components can be a turntable and / or a sieve plate, and dynamic internal components can be a vibrating sieve plate and / or a turbine.

[0024] In this invention, the extraction temperature can be selected over a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the extraction temperature is 25-130°C.

[0025] In this invention, there are no special requirements for the extraction time. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the extraction time is 10-60 min.

[0026] In this invention, there are no special requirements for the contact method during the extraction process. According to a preferred embodiment of the invention, the contact method for extraction is countercurrent contact. The inlet positions of the oil slurry and the extractant are determined by their densities. The denser fluid enters from the upper side of the extraction tower, while the less dense fluid enters from the lower side of the tower, achieving countercurrent contact within the tower. During this process, the extractant breaks down the inclusions formed by the polar adsorption of colloids, asphaltenes, and catalyst powder, releasing the catalyst powder. The raffinate phase 1, which has low solubility with the extractant, has a low density and is distributed in the upper layer, but has a high viscosity, trapping most of the catalyst powder in the oil slurry, especially small particles. A small number of larger particles settle into the lower raffinate phase 1.

[0027] According to a preferred embodiment of the present invention, the desolidation temperature of the raffinate phase 1 is lower than the extraction temperature, and more preferably, the desolidation temperature of the raffinate phase 1 is 0-60°C. Since the desolidation temperature of the raffinate phase 1 is lower than the extraction temperature, it will further release the saturated components dissolved therein at high temperatures. Because the density of the catalyst powder is comparable to that of the oil slurry, which is greater than that of the mixture of the saturated components and a small amount of solvent, it can quickly separate into layers, with the catalyst distributed at the bottom of the tank.

[0028] In this invention, no special requirements are placed on the equipment for removing solids and extractant from the raffinate phase 1. According to a preferred embodiment of the invention, the solidification of the raffinate phase 1 is carried out in a settling separator with a narrowed bottom. In this embodiment, a settling tank with a narrowed bottom is used to illustrate the advantages of the invention. The settling separator with a narrowed bottom facilitates the release of catalyst powder that has accelerated settling. At the same time, a differential pressure level gauge can be used to control the interface, and the bottom valve can be automatically opened according to the density difference to release the catalyst powder that has settled at the bottom of the separator.

[0029] In this invention, there are no special requirements for the deconsolidation time of the raffinate phase 1. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the deconsolidation time of the raffinate phase 1 is 2-8 hours.

[0030] In this invention, there is no special limitation on the position where the raffinate phase 1 enters the settling separator; for example, it can enter from the middle of the settling separator.

[0031] In this invention, there are no particular limitations on the method for removing solids from the extraction phase 1. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the method for removing solids from the extraction phase 1 is selected from cross-flow membrane filtration, dead-end filtration, and settling. From the perspective of solid removal effect, cross-flow membrane filtration is more effective; from an economic perspective, dead-end filtration or settling is better. Settling or dead-end filtration is more economical. After depolymerization and extraction by the extractant, most of the catalyst powder overflows from the top of the column and separates. A small amount of catalyst powder with larger particle size, due to its high density, is distributed in the extraction phase 1 and moves towards the bottom of the column. After settling, it easily settles to the bottom.

[0032] In this invention, when the extraction phase 1 removes solids using a cross-flow membrane filtration system, the pore size of the cross-flow membrane filtration system is selected based on the particle size of the catalyst powder in the extraction phase 1. According to a preferred embodiment of the invention, the pore size of the cross-flow membrane filtration system is 0.1-50 μm. Further, the particle size of the catalyst powder in the extraction phase 1 depends on the saturation content of the oil slurry. If the oil slurry is of medium to low saturation content, the resulting upper raffinate phase 1 has a moderate content and a moderate carrying capacity for solid particles in the oil slurry. A small portion of smaller particles will settle into the extraction phase 1 and need to be separated in subsequent processes, requiring the use of a membrane with a smaller pore size for separation. If the oil slurry is of high saturation content, the resulting upper raffinate phase 1 has a higher content and a higher carrying capacity for solid particles in the oil slurry. Almost no smaller particles will settle into the extraction phase 1, and the larger particles that need to be separated in subsequent processes will require the use of a membrane with a larger pore size for separation.

[0033] In this invention, there are no special requirements for the method of removing the extractant from the extraction phase 1. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the method of removing the extractant from the extraction phase 1 is selected from one or more of flash distillation, vacuum distillation, stripping distillation, and molecular distillation. In this embodiment of the invention, flash distillation is used as the method of removing the extractant to illustrate the advantages of the invention.

[0034] In this invention, there is no particular limitation on the specific type of extractant. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the extractant is selected from one or more of furfural, DMF, N-methylpyrrolidone, dimethyl sulfoxide and sulfolane.

[0035] According to a preferred embodiment of the present invention, the density of the extractant is less than the density of the oil slurry, and more preferably, the density is between the densities of the saturated and aromatic components in the oil slurry. Using the aforementioned technical solution, better extraction can be achieved. After the oil slurry comes into contact with the solvent, it releases the saturated components with low solubility and low density, which carry solid particles to the top of the column, while the aromatic components, colloids, and asphaltenes with high density and high polarity dissolved in the oil slurry are carried to the bottom of the column. During the upward movement of the raffinate, it comes into countercurrent contact with the fresh extractant, dissolving the small amount of aromatic components carried therein and moving them to the bottom of the column, thus improving the selectivity of the extraction.

[0036] In this invention, there are no special requirements for the components and contents of the catalytic slurry. The following is an example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the catalytic slurry contains, by weight: 15-65% saturated components, 25-65% aromatic components, 8-20% gum, and 1-8% asphaltenes.

[0037] The technical solution of the present invention can achieve the desolidification treatment of catalytic oil slurry with different solid contents, and can achieve the desolidification effect. There are no special requirements for the solid content of the catalytic oil slurry. The following is an example, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the solid content of the catalytic oil slurry is 1500-5000ppm.

[0038] The present invention will be described in detail below through embodiments.

[0039] In the following embodiments, The particle size of the catalyst particles remaining in the extraction phase 1 was obtained by a particle size analyzer. The testing principle was laser diffraction, and the principle is described in ISO 13320-1. The yield of aromatic hydrocarbon-rich slurry in the product is the portion remaining after slurry pretreatment to remove residual oil and solid particles, which is calculated by weighing. Solid content is the percentage of solid particles retained on the filter paper after filtering a certain amount of sample, which is calculated by weighing the sample. The viscosity of the extraction phase 3 was measured according to GB / T11137; Furfural and DMF reagents are of analytical grade, with a purity of not less than 95%. In this embodiment of the invention, the slurry feedstock is derived from the heavy components of the catalytic cracking products containing solid catalyst powder, which are thrown off the bottom of the distillation tower of the catalytic cracking unit. The saturated components in the slurry feedstock are mainly alkanes. Detailed parameters are shown in Table 1.

[0040] Example 1 The process flow diagram of this embodiment is as follows: Figure 1As shown: Furfural and oil slurry feedstock 1 were separately introduced into the extraction tower of the extraction unit at a ratio of 0.5:1. Furfural entered from the top inlet of the extraction tower, while oil slurry feedstock 1 entered from the bottom, and they were in countercurrent contact within the tower. The extraction tower temperature was set to 40℃, and the extraction time was set to 10 min. After extraction, an upper raffinate phase 1 and a lower extractable phase 1 were obtained. Raffinate phase 1 overflowed from the top of the tower and settled in a settling tank (with a narrowed bottom) to separate into layers. The upper raffinate oil was returned to the catalytic cracking unit as feedstock, and the lower extractant, rich in solid components at the bottom, was returned to the extraction tower for reuse. The settling tank temperature was set to 20℃, and the settling time was 2 h.

[0041] Extraction phase 1 is collected from the bottom of the extraction tower. Due to the low proportion of furfural added, a process of first removing solids and then removing the extractant is adopted. Cross-flow membrane filtration is performed using a membrane tube with a pore size of 0.1 μm. After filtration, a deeply desolidified filtrate is obtained, which is then subjected to flash evaporation and stripping distillation to remove the extractant, resulting in a deeply desolidified aromatic hydrocarbon-enriched slurry. The removed extractant is returned to the extraction tower for reuse. The concentrate containing solids after membrane filtration is returned to the extraction unit for processing. The basic properties of slurry feedstock 1 are shown in Table 1 below. The yield of the final product, the aromatic hydrocarbon-enriched slurry, is 92.5%, and the solid content is 18.7 ppm.

[0042] Example 2 The process flow diagram of this embodiment is as follows: Figure 2 As shown: Furfural and oil slurry feedstock 2 were fed separately into the extraction tower at a ratio of 1.5:1. Furfural entered through the top inlet of the extraction tower, while oil slurry feedstock 2 entered through the bottom, and they were in countercurrent contact within the tower. The extraction tower temperature was set to 80℃, and the extraction time was set to 30 min. After extraction, an upper raffinate phase 1 and a lower extractable phase 1 were obtained. The raffinate phase overflowed from the top of the tower and settled in a settling tank (with a narrowed bottom) to separate into layers. The upper raffinate oil was returned to the catalytic cracking unit as feedstock, and the lower extractant, rich in solid components at the bottom, was returned to the extraction tower for reuse. The settling tank temperature was set to 30℃, and the settling time was 4 h.

[0043] Extractive phase 1 was collected from the bottom of the extraction column. Due to the high proportion of furfural solvent added, a process of first removing the extractant and then removing the solids was adopted. First, flash evaporation was performed to remove most of the extractant, yielding extractive phase 3 (viscosity 30 mm). 2 / s), the removed extractant is returned to the extraction tower for reuse.

[0044] Extraction phase 3 enters the desolidification unit, where it undergoes cross-flow membrane filtration using a 0.5 μm pore size membrane tube. After filtration, a deeply desolidified filtrate is obtained. This filtrate is then stripped by distillation to remove residual solvent, yielding the extracted oil, i.e., the aromatic-rich oil slurry. The solids-containing concentrate after membrane filtration is returned to the extraction unit. The basic properties of oil slurry feedstock 2 are shown in Table 1 below. The final product shows an aromatic-rich oil slurry yield of 87.2% and a solids content of 30.3 ppm.

[0045] Example 3 The process flow diagram of this embodiment is as follows: Figure 2 As shown, furfural and oil slurry feedstock No. 3 were fed separately into the extraction tower at a ratio of 3:1. Furfural entered through the top inlet of the extraction tower, while oil slurry feedstock No. 3 entered through the bottom, and they were in countercurrent contact within the tower. The extraction tower temperature was set at 120℃, and the extraction time was set at 60 min. After extraction, an upper raffinate phase 1 and a lower extractable phase 1 were obtained. The raffinate phase overflowed from the top of the tower and settled in a settling tank (with a narrowed bottom) to separate into layers. The upper raffinate oil was returned to the catalytic cracking unit as feedstock, and the lower extractant, rich in solid components at the bottom, was returned to the extraction tower for reuse. The settling tank temperature was set at 60℃, and the settling time was 8 h.

[0046] Extractive phase 1 was collected from the bottom of the extraction column. Due to the high proportion of furfural solvent added, a process of first removing the extractant and then removing the solids was adopted. First, flash evaporation was performed to remove most of the extractant, yielding extractive phase 3 (viscosity 20 mm). 2 / s), the removed extractant is returned to the extraction tower for reuse.

[0047] Extraction phase 3 enters the deconsolidation unit, where it undergoes cross-flow membrane filtration using a 0.1 μm pore size membrane tube. After filtration, a deeply deconsolidated filtrate is obtained. This filtrate is then stripped by distillation to remove residual solvent, yielding the extracted oil, i.e., the aromatic-rich slurry. The basic properties of slurry feedstock 3 are shown in Table 1 below. The final product, containing aromatic-rich slurry, has a yield of 95.2% and a solid content of 15 ppm.

[0048] Example 4 The method was followed in Example 2, except that the solidification of the extraction phase 3 was performed using a dead-end filtration process with a 0.5 μm sintered metal mesh; all other conditions remained unchanged. The final product had an aromatic-rich oil slurry yield of 87.8% and a solid content of 37.2 ppm.

[0049] Example 5 The method was followed in Example 3, except that the solidification of the extraction phase 3 was performed using a static sedimentation process, while other conditions remained unchanged. The final product had an aromatic-rich oil slurry yield of 89.5% and a solid content of 49.3 ppm.

[0050] Example 6 The process flow diagram of this embodiment is as follows: Figure 1As shown: DMF (extractant) and oil slurry feedstock 1 were fed separately into the extraction tower at a ratio of 0.5:1. DMF entered through the lower inlet of the extraction tower, while oil slurry feedstock 1 entered through the upper inlet, and they were in countercurrent contact within the tower. The extraction tower temperature was set to 40℃, and the extraction time was set to 10 min. After extraction, an upper raffinate phase 1 and a lower extractable phase 1 were obtained. The raffinate phase overflowed from the top of the tower and settled in a settling tank (with a narrowed bottom) to separate into layers. The upper raffinate oil was returned to the catalytic cracking unit as feedstock, and the lower extractant, rich in solid components at the bottom, was returned to the extraction tower for reuse. The settling tank temperature was set to 20℃, and the settling time was 2 h.

[0051] Extraction phase 1 was collected from the bottom of the extraction column. Due to the low proportion of DMF solvent added, a process of first removing the solids and then removing the extractant was adopted. Cross-flow membrane filtration was performed using a membrane tube with a pore size of 0.1 μm. After filtration, a deeply desolventized filtrate was obtained, which was then subjected to flash evaporation and stripping distillation to remove the extractant, resulting in a deeply desolventized aromatic-rich slurry. The removed extractant was returned to the extraction column for reuse. The concentrate containing solids after membrane filtration was returned to the extraction unit for further processing. The final product had an aromatic-rich slurry yield of 95.3% and a solids content of 11.2 ppm.

[0052] Example 7 Following the method of Example 2, the difference was that the ratio of furfural to oil slurry feedstock 2 was 4:1, and a process of first removing the extractant and then desolidifying was employed. The final product had an aromatic-rich oil slurry yield of 88.5% and a solid content of 23 ppm. Analysis of the results showed that excessive extractant addition resulted in good selectivity in the extraction and separation, but also reduced the proportion of saturated fractions in the raffinate phase 1. This led to a poorer adhesion effect on the catalyst powder in the oil slurry. Because the raffinate phase 1 contained a large amount of extractant, its viscosity was too low, causing some catalyst powder to enter the raffinate phase 1. However, this desolidification was achieved after subsequent treatment. Due to the large amount of extractant used in the extraction, energy consumption also increased accordingly, making this not a preferred solution.

[0053] Comparative Example 1 The method was followed in Example 2, except that the ratio of furfural to raw material No. 2 was 0.3:1. At this ratio, a process of first removing the solids and then removing the extractant was employed. The final product had an aromatic-rich oil slurry yield of 82.3% and a solid content of 108.9 ppm, which did not meet the required solid content.

[0054] Table 1 Basic parameters of oil slurry feedstock

[0055] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for synergistic treatment of aromatic hydrocarbon enrichment and solid removal in oil slurry, characterized in that, The method includes: (1) Extraction is carried out by contacting the extractant and the catalytic oil slurry to obtain raffinate phase 1 and extract phase 1, wherein the mass ratio of the extractant to the catalytic oil slurry is not less than 0.5; (2) After removing solids and extractant from raffinate phase 1, raffinate oil is obtained. The removed extractant is returned to step (1) for extraction. After removing solids and extractant from extraction phase 1, aromatic-enriched desoldered oil slurry is obtained. The removed extractant is returned to step (1) for extraction.

2. The method according to claim 1, characterized in that, The mass ratio of the extractant to the catalytic slurry is (0.5-3):

1.

3. The method according to claim 1 or 2, characterized in that, The step of obtaining an aromatic-enriched deconsolidated oil slurry after removing solids and extractant from extraction phase 1, wherein the mass ratio of extractant to catalytic oil slurry is not higher than 1:1, includes: Extraction phase 1 is desolventized to obtain extraction phase 2. Extraction phase 2 is desolventized to obtain aromatic-enriched desolventized oil slurry. The extractant removed from extraction phase 2 is returned to the extraction tower for reuse.

4. The method according to claim 1 or 2, characterized in that, The step of obtaining an aromatic-enriched deconsolidated oil slurry after the extraction phase 1 removes solids and extractant, with the mass ratio of extractant to catalytic oil slurry being higher than 1:1, includes: Extraction phase 1 is de-extracted to obtain extraction phase 3. Extraction phase 3 is de-solidified and de-extracted to obtain aromatic-enriched oil slurry. The extractant removed from extraction phase 1 is returned to the extraction tower for reuse.

5. The method according to claim 4, characterized in that, The solid-free portion of the extraction phase 3 is returned to the catalytic slurry for re-extraction.

6. The method according to claim 5 or 6, characterized in that, The viscosity of the extraction phase 3 is 1-150 mm. 2 .s.

7. The method according to claim 1 or 2, characterized in that, The extraction conditions include: Temperatures range from 25 to 130°C; and / or The time is 10-60 minutes; and / or The extraction contact method is countercurrent contact.

8. The method according to claim 1 or 2, characterized in that, The temperature at which the raffinate phase 1 is desolidified is lower than the extraction temperature.

9. The method according to claim 8, characterized in that, The temperature at which the raffinate phase 1 is desolidified is 0-60℃.

10. The method according to claim 1 or 2, characterized in that, Deconsolidation of the raffinate phase 1 is carried out in a settling separator with a narrowed bottom; and / or The time for desolidification of the raffinate phase 1 is 2-8 hours.

11. The method according to claim 1 or 2, characterized in that, The method for removing solids from the extraction phase 1 is selected from one of cross-flow membrane filtration, dead-end filtration, and settling.

12. The method according to claim 11, characterized in that, The cross-flow membrane filter has a membrane pore size of 0.1-50 μm.

13. The method according to claim 1 or 2, characterized in that, The method for removing the extractant from the extraction phase 1 is selected from one or more of flash distillation, vacuum distillation, stripping distillation, and molecular distillation.

14. The method according to claim 1 or 2, characterized in that, The extractant is selected from one or more of furfural, DMF, N-methylpyrrolidone, dimethyl sulfoxide, and sulfolane.

15. The method according to claim 14, characterized in that, The density of the extractant is less than that of the oil slurry.

16. The method according to claim 1 or 2, characterized in that, By weight, the catalytic slurry contains: 15-65% saturated components, 25-65% aromatic components, 8-20% gums, 1-8% asphaltenes; and / or The solid content of the catalytic slurry is 1500-5000 ppm.

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