Method for increasing yield of heavy naphtha by adopting slurry bed hydrogenation device

Abstract

The invention belongs to the technical field of petrochemical engineering, and relates to a method for increasing the yield of heavy naphtha by adopting a slurry bed hydrogenation device. According to the method, normal-pressure fractionation is carried out on the mixed oil obtained after the hydrogenation reaction of the slurry reactor, on the premise that an atmospheric tower is not transformed, operation parameters are optimized and adjusted, and gas-liquid phase distribution and product cutting points in the tower are changed, so that more C11 and part of suitable components in diesel oil fractions are transferred into heavy naphtha fractions, and the yield of heavy naphtha is increased; meanwhile, the quality control index of the heavy naphtha is changed from traditional final boiling point control to control based on specific component content, so that the heavy naphtha after yield increase meets the feeding requirements of subsequent naphtha hydrogenation and reforming devices.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical technology and relates to a method for increasing the production of heavy naphtha using a slurry bed hydrogenation unit. Background Technology

[0002] The slurry-bed hydrotreating unit employs slurry-bed residue hydrotreating technology, a key process in modern oil refining for converting heavy crude oil and increasing the yield of light oils. This technology typically uses vacuum residue from atmospheric and vacuum distillation as feedstock, undergoing hydrocracking and hydrorefining reactions under the action of a molybdenum-based catalyst. This process involves thermal cracking and catalytic hydrogenation of the feedstock, inhibiting coking, promoting desulfurization, denitrification, and deoxygenation, and simultaneously removing halogenated sulfur, nitrogen, and metallic impurities. The result is a series of products including desulfurized fuel gas, liquefied petroleum gas (LPG), naphtha, diesel oil, wax oil, and oil residue.

[0003] In slurry-bed residue hydrotreating units, the atmospheric distillation column receives the reaction oil and performs distillation range separation on the reaction effluent. The separation efficiency directly determines the yield and quality of products such as diesel, heavy naphtha, and wax oil. In traditional operating modes, the operating parameters of the atmospheric distillation column are typically optimized to produce qualified diesel and ensure stable feedstock for downstream diesel hydrotreating or cracking units. The processing route cannot be flexibly adjusted, which to some extent limits the value of heavy naphtha as a high-quality reforming feedstock. Heavy naphtha is rich in cycloalkanes and aromatic precursors, making it a high-quality catalytic reforming feedstock. Its potential economic benefits in producing high-octane gasoline or high-value chemical products such as BTX (benzene, toluene, xylene) far exceed those of using it as a diesel component.

[0004] Therefore, those skilled in the art have been seeking methods to optimize existing slurry bed residue hydrotreating units in order to increase the production of heavy naphtha while ensuring that the final boiling point does not exceed 180°C. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, the present invention aims to provide a method for increasing the production of heavy naphtha using a slurry bed hydrogenation unit, thereby overcoming the shortcomings of the prior art.

[0006] One aspect of the present invention provides a method for increasing the production of heavy naphtha using a slurry bed hydrotreating unit, comprising the following steps: The residue oil from the atmospheric and vacuum distillation unit is fed into the slurry bed hydrotreating unit. After being mixed with hydrogen, it enters the reactor for thermal cracking. After separation by the slurry fractionation system, the oil enters the feed buffer tank of the atmospheric fractionation system. The oil in the feed buffer tank is heated and then introduced into the lower section of the atmospheric distillation tower for fractionation. After separation by the atmospheric distillation tower, wax oil, diesel oil and heavy naphtha products are obtained.

[0007] Slurry-bed hydrotreating technology is a key technology specifically designed for processing heavy and low-quality feedstocks such as residual oil and coal liquefaction oil. Compared to the limitations of traditional fixed-bed reactors, which are prone to deactivation due to impurity blockage, this technology adopts a gas-liquid co-current reaction mode, forming a slurry bed with micron-sized catalyst particles. This not only effectively solves the problems of increased bed pressure drop and rapid catalyst deactivation, but also achieves extremely high reactivity and catalyst utilization efficiency due to the elimination of internal diffusion effects. It can efficiently remove impurities such as metals, gums, residual carbon, sulfur, and nitrogen from heavy oil products, achieving high conversion rates of heavy oil and high yields of light oil, demonstrating significant technical advantages and application prospects.

[0008] Preferably, the mass ratio of residual oil to hydrogen is 11~13:1.

[0009] Preferably, the pressure of the thermal cracking reaction is 12~20 MPa and the reaction temperature is 400~450℃.

[0010] Preferably, the reactor is a slurry bubbling reactor.

[0011] The thermal cracking reaction is carried out in the presence of a catalyst. Preferably, the catalyst is added at a mass of 0.1 to 0.3% of the raw material, and the catalyst is a molybdenum-based catalyst.

[0012] The gas-liquid-solid three-phase slurry product generated by the thermal cracking reaction is discharged from the reactor and enters the slurry fractionation system. The separated oil is transported to the feed buffer tank of the atmospheric fractionation system and then fractionated in the atmospheric distillation tower. This invention aims to increase the yield of heavy naphtha by optimizing and adjusting the operating parameters of the atmospheric distillation tower to extract the C11 component from the diesel fraction into the heavy naphtha fraction. The operating parameters of the atmospheric distillation tower include: Under 100% load operation conditions of slurry bed hydrogenation unit: The temperature at the top of the tower is 144~148℃ The pressure at the top of the tower is 0.14~0.16 MPa; Heavy naphtha tower top reflux flow rate: 37~39 t / h; The side-stream diesel stripping tower has a stripping steam output of 80~120 kg / h and an atmospheric pressure tower bottom stripping steam output of 800~1200 kg / h. Mid-section circulation rate: 210~230 t / h; The return temperature in the middle section of the tower is 170~175℃; The feed rate of the atmospheric pressure tower is 160~170 t / h; The feed temperature is 310~312℃.

[0013] During fractionation, a portion of the liquid is drawn from the middle tray of the rectification section of the atmospheric distillation column, cooled by a cooler, and then returned to the corresponding tray in the column. This circulation volume is called the middle section circulation volume.

[0014] Preferably, the operating parameters of the atmospheric distillation column also include: The extraction temperature in the middle section is 230~245℃; The bottom temperature of the atmospheric pressure column is 255~265℃; The side-stream diesel extraction temperature is 235~245℃, and the extraction rate is 110~120t / h; The production capacity of heavy naphtha is 55~65t / h.

[0015] Due to the high C content in diesel fuel 11 To increase heavy naphtha production, the original heavy naphtha final boiling point control index has exceeded the threshold; therefore, this index is now cancelled, and a staged control strategy based on carbon composition is adopted. Preferably, the heavy naphtha recovery index is: C content... 11 The content of the above components is controlled at 1.0~2.8wt%, C 12 The content of the above components is ≤0.15wt%.

[0016] Preferably, the method for increasing the production of heavy naphtha using a slurry bed hydrogenation unit in this invention achieves a heavy naphtha yield of 9.0-9.8%.

[0017] A second aspect of the present invention provides a heavy naphtha, which is obtained by the above-described method.

[0018] Preferably, the heavy naphtha contains C 11 The content of the above components is 1.0~2.8wt%, C 12 The content of the above components is ≤0.15wt%.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. In the method of the present invention, the mixed oil from the slurry bed hydrotreating reaction is subjected to atmospheric distillation. Without modifying the atmospheric distillation tower, the operating parameters are optimized and adjusted to change the gas-liquid phase distribution and product cut-off point in the tower, thereby transferring more C11 and some suitable components from the diesel fraction to the heavy naphtha fraction, thus increasing the production of heavy naphtha. At the same time, the quality control index of heavy naphtha is changed from the traditional final boiling point control to control based on the content of specific components, so as to ensure that the increased production of heavy naphtha meets the feed requirements of subsequent naphtha hydrotreating and reforming units.

[0020] 2. After adjusting the operating parameters of the atmospheric distillation column at 100% load, the heavy naphtha yield of the slurry bed hydrogenation unit significantly increased to 9.6%, and the C content in the heavy naphtha increased. 11 After the composition was adjusted, the content was increased to 2.1%, and the content of C12 and above components was ≤0.15%. Moreover, after the process adjustment, the product quality of heavy naphtha was not adversely affected, thus achieving the goal of increasing the production of heavy naphtha without reducing its quality.

[0021] 3. The process of this invention adjusts the yield of heavy naphtha and the C content of the heavy naphtha components. 11 The adjustments provide more options for the implementation of projects optimizing heavy naphtha processing routes. The heavy naphtha product can be processed not only in diesel cracking units but also in naphtha hydrotreating units, and can also be sent to reforming units as feedstock.

[0022] 4. By increasing the yield of heavy naphtha and expanding its downstream utilization pathways, the process of this invention significantly enhances the comprehensive utilization value and economic contribution of heavy naphtha. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the atmospheric distillation system of the slurry bed hydrogenation device in this invention. Detailed Implementation

[0024] The present invention provides a method for increasing the production of heavy naphtha using a slurry bed hydrogenation unit. However, these embodiments are exemplary, and the scope of the invention is not limited thereto. Furthermore, the accompanying drawings used herein are merely for better illustration of the invention and do not limit the scope of protection.

[0025] A method for increasing the production of heavy naphtha using a slurry bed hydrogenation unit includes the following steps: Residue oil from the atmospheric and vacuum distillation unit is fed into the slurry bed hydrotreating unit and mixed with hydrogen at a mass ratio of 11-13:1. After mixing, the mixture is conveyed into the slurry bubbling reactor for thermal cracking. The thermal cracking reaction is carried out in the presence of a catalyst, which is added at a mass of 0.1-0.3% of the feedstock. The catalyst is a molybdenum-based catalyst. The thermal cracking reaction pressure is 12-20 MPa, and the reaction temperature is 400-450℃. The gas-liquid-solid three-phase slurry product generated by the thermal cracking reaction is discharged from the reactor and enters the slurry fractionation system. The separated oil is conveyed to the feed buffer tank of the atmospheric fractionation system. Figure 1 This is a schematic diagram of the atmospheric distillation system of a slurry bed hydrogenation unit, combined with... Figure 1A detailed description of the atmospheric distillation system process is provided: The oil in the feed buffer tank V-5001 is heated by heat exchangers E5001-E5006 and heater F-5001, controlling the oil temperature to 310~312℃. After heat treatment, it is introduced into the lower section of the atmospheric distillation tower for fractionation: wax oil is discharged from the bottom of the tower, and diesel oil is discharged from the side stream into the diesel stripping tower C-5002. Stripping steam MS is introduced from the diesel stripping tower C-5002. The steam rises from bottom to top, fully contacting the diesel oil flowing downwards. Utilizing the "carrying effect" of the steam, the oil is separated from the diesel oil. The remaining light components are vaporized; the vaporized light components are discharged from the top of the stripping tower along with the steam and returned to the corresponding temperature section of the atmospheric tower; the diesel oil, after the light components have been removed, is discharged from the bottom of the stripping tower, becoming qualified diesel oil; the heavy naphtha produced at the top of the atmospheric tower is first cooled by an air cooler (A-5001) and a cooler (E-5007), and the cooled heavy naphtha enters the "atmospheric tower top reflux tank V-5002" for gas-liquid separation; a portion of the heavy naphtha is refluxed to the top of the atmospheric tower via pump P-5005, and the other portion is sent out as a product through pipeline. After separation in the atmospheric tower, wax oil, diesel oil, and heavy naphtha products are obtained.

[0026] During the fractionation process, the operating parameters of the atmospheric distillation column are adjusted as follows: bottom temperature of the atmospheric distillation column is 255~265℃, bottom stripping steam flow rate is 800~1200 kg / h, feed temperature is 310~312℃, feed rate is 160~170 t / h, mid-section extraction temperature is 230~245℃, mid-section circulation rate is 210~230 t / h, mid-section return temperature is 170~175℃, side-stream diesel extraction temperature is 235~245℃, extraction rate is 110~120 t / h, side-stream stripping rate is 80~120 kg / h, top temperature is 144~148℃, top pressure is 0.14~0.16 MPa, heavy naphtha extraction rate is 55~65 t / h, and top reflux rate is 37~39 t / h.

[0027] By adjusting the process parameters of the atmospheric distillation tower, the C11 component in the diesel fraction can be extracted into the heavy naphtha fraction, thereby increasing the yield of heavy naphtha.

[0028] Example 1 The method for increasing the production of heavy naphtha using a slurry bed hydrogenation unit in this embodiment includes the following specific steps: Residue oil from the atmospheric and vacuum distillation unit is fed into the slurry bed hydrotreating unit and mixed with hydrogen at a mass ratio of 12.4:1. After mixing, the mixture is conveyed into the slurry bubbling reactor for thermal cracking. The thermal cracking reaction is carried out in the presence of a molybdenum-based catalyst, with the catalyst added at 0.11% of the feed mass. The thermal cracking reaction pressure is 16 MPa, and the reaction temperature is 420 °C. The gas-liquid-solid three-phase slurry product generated by the thermal cracking reaction is discharged from the reactor and enters the slurry fractionation system. The separated oil is conveyed to the feed buffer tank of the atmospheric distillation system.

[0029] The oil in the feed buffer tank undergoes temperature control via a heat exchanger and heater, maintaining a temperature of 311℃. After heat treatment, it is introduced into the lower section of the atmospheric distillation tower for fractionation: wax oil is discharged from the bottom of the tower; diesel oil is discharged from the side stream and enters the diesel stripping tower. Stripping steam is introduced into the diesel stripping tower, rising from bottom to top and fully contacting the diesel oil flowing from top to bottom, vaporizing the residual light components in the diesel oil. The vaporized light components are discharged from the top of the stripping tower along with the steam, returning to the corresponding temperature section of the atmospheric distillation tower; the diesel oil after the light components have been removed is discharged from the bottom of the stripping tower, becoming qualified diesel oil; according to the indicators: C in the composition 11 The content of the above components is controlled between 1-2.8%, C 12 Heavy naphtha with a content of ≤0.15% or higher is produced at the top of the atmospheric pressure tower. After cooling, the heavy naphtha enters the "atmospheric pressure tower top reflux tank" for gas-liquid separation. Part of the heavy naphtha is pumped back to the top of the atmospheric pressure tower, and the other part of the heavy naphtha is sent out as a product through pipeline.

[0030] With a 100% load of 357 t / h, the operating parameters of the atmospheric distillation column during the fractionation process are shown in Table 1.

[0031] Example 2 The method for increasing the production of heavy naphtha using a slurry bed hydrogenation unit in this embodiment includes the following specific steps: Residue oil from the atmospheric and vacuum distillation unit is fed into the slurry bed hydrotreating unit and mixed with hydrogen at a mass ratio of 13:1. After mixing, the mixture is conveyed into the slurry bubbling reactor for thermal cracking. The thermal cracking reaction is carried out in the presence of a molybdenum-based catalyst, with the catalyst added at 0.15% of the feed mass. The thermal cracking reaction pressure is 18 MPa, and the reaction temperature is 430 °C. The gas-liquid-solid three-phase slurry product generated by the thermal cracking reaction is discharged from the reactor and enters the slurry fractionation system. The separated oil is conveyed to the feed buffer tank of the atmospheric distillation system.

[0032] The oil in the feed buffer tank undergoes temperature control via a heat exchanger and heater, maintaining a temperature of 312℃. After heat treatment, it is introduced into the lower section of the atmospheric distillation tower for fractionation: wax oil is discharged from the bottom of the tower; diesel oil is discharged from the side stream and enters the diesel stripping tower. Stripping steam is introduced into the diesel stripping tower, rising from bottom to top and fully contacting the diesel oil flowing from top to bottom, vaporizing the residual light components in the diesel oil. The vaporized light components are discharged from the top of the stripping tower along with the steam, returning to the corresponding temperature section of the atmospheric distillation tower; the diesel oil after the light components have been removed is discharged from the bottom of the stripping tower, becoming qualified diesel oil; according to the indicators: C in the composition 11 The content of the above components is controlled between 1-2.8%, C 12 Heavy naphtha with a content of ≤0.15% or higher is produced at the top of the atmospheric pressure tower. After cooling, the heavy naphtha enters the "atmospheric pressure tower top reflux tank" for gas-liquid separation. Part of the heavy naphtha is pumped back to the top of the atmospheric pressure tower, and the other part of the heavy naphtha is sent out as a product through pipeline.

[0033] With a 100% load of 357 t / h, the operating parameters of the atmospheric distillation column during the fractionation process are shown in Table 1.

[0034] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is the operating parameters of the atmospheric pressure column. The operating parameters of the atmospheric pressure column in Comparative Example 1 are shown in Table 1.

[0035] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is the operating parameters of the atmospheric pressure column. The operating parameters of the atmospheric pressure column in Comparative Example 2 are shown in Table 1.

[0036] .

[0037] As shown in Table 1, the yields of Examples 1 and 2 were 9.6% and 9.4%, respectively, which were significantly higher than those of Comparative Examples 1-2. Furthermore, the heavy naphtha obtained using the method of this invention all met the requirement of a final boiling point below 180°C, the content of C11 and higher components was precisely controlled within the target range of 1%-2.8%, and the content of C12 and higher components was strictly limited to below 0.05%.

[0038] The heavy naphtha products of Example 1 and Comparative Example 1 were analyzed by laboratory testing, and the results are shown in Table 2: .

[0039] As shown in Table 2, the light component in Example 1 was significantly reduced, while the proportion of C9+, especially C10+ and C11+ heavy components, was significantly increased. This indicates that the product cut-off point was shifted later, light-end entrainment was effectively controlled, the composition of the heavy naphtha fraction was more concentrated, the heavy-end characteristics were more prominent, and the product quality was better matched with the positioning of heavy naphtha. Tables 1 and 2 show that the parameter optimization of the present invention significantly improved the yield of heavy naphtha without negatively impacting product quality.

[0040] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.

[0041] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A method for increasing the production of heavy naphtha using a slurry bed hydrogenation unit, characterized in that, Includes the following steps: The residue oil from the atmospheric and vacuum distillation unit is fed into the slurry bed hydrotreating unit. After being mixed with hydrogen, it enters the reactor for thermal cracking. After separation by the slurry fractionation system, the oil enters the feed buffer tank of the atmospheric fractionation system. The oil in the feed buffer tank is heated and then introduced into the lower section of the atmospheric distillation tower for fractionation. After separation by the atmospheric distillation tower, wax oil, diesel oil and heavy naphtha products are obtained. Under 100% load operation conditions, the operating parameters of the atmospheric distillation column in a slurry-bed hydrogenation unit include: The temperature at the top of the tower is 144~148℃; The pressure at the top of the tower is 0.14~0.16 MPa; The reflux flow rate at the top of the heavy naphtha tower is 37~39 t / h; The stripping steam rate of the side-stream diesel stripping tower is 80~120 kg / h; The stripping steam flow rate at the bottom of the atmospheric pressure tower is 800~1200 kg / h; The intermediate circulation rate is 210~230 t / h; The return temperature in the middle section of the tower is 170~175℃; The feed rate of the atmospheric pressure tower is 160~170 t / h; The feed temperature is 310~312℃.

2. The method according to claim 1, characterized in that, The mass ratio of residual oil to hydrogen is 11~13:

1.

3. The method according to claim 1, characterized in that, The pressure of the thermal cracking reaction is 12~20 MPa, and the reaction temperature is 400~450℃.

4. The method according to claim 1, characterized in that, The reactor is a slurry bubbling reactor.

5. The method according to claim 1, characterized in that, The thermal cracking reaction is carried out in the presence of a catalyst, which is added at a mass of 0.1-0.3% of the raw material. The catalyst is a molybdenum-based catalyst.

6. The method according to claim 1, characterized in that, The operating parameters of an atmospheric distillation column also include: The extraction temperature in the middle section is 230~245℃; The bottom temperature of the atmospheric pressure column is 255~265℃; The side-stream diesel extraction temperature is 235~245℃, and the extraction rate is 110~120t / h; The production capacity of heavy naphtha is 55~65t / h.

7. The method according to claim 1, characterized in that, Heavy naphtha recovery index is: C content in the composition 11 The content of the above components is controlled at 1.0~2.8wt%, C 12 The content of the above components is ≤0.15wt%.

8. The method according to claim 1, characterized in that, The yield of heavy naphtha is 9.0-9.8%.

9. A type of heavy naphtha, characterized in that, It is obtained by extraction using the method described in any one of claims 1 to 8.

10. The heavy naphtha according to claim 9, characterized in that, C in heavy naphtha 11 The content of the above components is 1.0~2.8wt%, C 12 The content of the above components is ≤0.15wt%.

Images