Method for on-line replacement and cascade regeneration of waste mineral oil hydrogenation microspherical catalyst

Abstract

The application provides an online replacement and cascade regeneration method of waste mineral oil hydrogenation microspherical catalyst, which is used in a waste mineral oil boiling bed-multipipe fixed bed combined hydrogenation process and comprises the following steps: monitoring parameters, discharging the deactivated microspherical catalyst when the parameters reach the threshold value, and synchronously supplementing the same amount of filled microspherical catalyst; washing the deactivated microspherical catalyst by using a washing solvent, removing impurities by filtration, and drying; performing first-stage low-oxygen controlled temperature calcination on the dried deactivated microspherical catalyst; performing second-stage oxygen-rich high-temperature calcination on the deactivated microspherical catalyst subjected to the first-stage low-oxygen controlled temperature calcination; obtaining regenerated microspherical catalyst after screening, mixing the regenerated microspherical catalyst with fresh microspherical catalyst to obtain filled microspherical catalyst, and completing the online replacement and cascade regeneration treatment of the waste mineral oil hydrogenation microspherical catalyst. The application can remove the impurities of the deactivated microspherical catalyst, realizes the synchronous performance of deep carbon removal and heavy metal poison removal, and greatly restores the specific surface area and hydrogenation active sites of the deactivated microspherical catalyst.

Description

Technical Field

[0001] This invention relates to the field of waste mineral oil resource utilization and waste catalyst regeneration and recycling technology, specifically to an online replacement and cascade regeneration method for waste mineral oil hydrogenation microsphere catalysts. Background Technology

[0002] In recent years, with the increasing severity and deterioration of crude oil and the surge in waste mineral oil production across various industries, environmental protection requirements have become increasingly stringent. How to achieve clean and efficient resource utilization of waste mineral oil to meet the growing market demand for light oil and aviation kerosene has become a crucial task in the global petroleum processing and solid waste treatment sectors. The fluidized bed hydrotreating process, due to its high degree of material backmixing within the reactor, low bed pressure drop, uniform temperature distribution, and strong feedstock adaptability, is widely used in the hydrotreating, depurification, and conversion of low-quality heavy oil and waste lubricating oil, and is attracting increasing attention from large petrochemical and environmental protection companies.

[0003] The fluidized bed hydrogenation process involves high reaction temperatures and vigorous three-phase fluidization, making it prone to the deposition and coking of large molecular colloidal substances and metallic impurities in waste mineral oil, leading to rapid catalyst deactivation. Especially in combined processes with downstream fixed beds, if the deactivation of the fluidized bed microsphere catalyst is not addressed promptly, large quantities of unconverted, inferior components will enter the downstream system, causing fluctuations throughout the entire system. Currently, the main methods for treating spent catalysts are offline carbon regeneration or direct treatment as solid hazardous waste, resulting in extremely high catalyst operating costs and significant environmental pressure.

[0004] Chinese patent document CN109876543A discloses a method for decarbonization and regeneration of spent hydrogenation catalysts. This method involves removing the deactivated catalyst from the reactor, performing preliminary extraction with conventional organic solvents, and then subjecting it to air roasting in a roasting furnace. While this method can restore some activity, it is an offline process that cannot address the problem of bed buildup during continuous operation of a fluidized bed reactor. Furthermore, simple high-temperature air roasting is insufficient to effectively remove deposited heavy metals (such as iron, vanadium, and nickel), and can easily damage the microsphere catalyst framework structure.

[0005] Chinese patent document CN111234567A discloses an online catalyst addition and removal system and method for a fluidized bed reactor. This system achieves dynamic catalyst addition and replacement through differential pressure control, effectively maintaining the fluidization state inside the reactor. However, the discharged waste catalyst is directly sent to a waste tank for cooling and then disposed of as solid waste, failing to achieve catalyst reactivation and recycling, resulting in high costs associated with both new catalyst procurement and hazardous waste treatment.

[0006] As can be seen from the above patents, existing technologies cannot restore the activity of deactivated catalysts and remove heavy metals and other impurities deposited on the catalysts when treating deactivated catalysts in fluidized bed reactors, thus failing to achieve recycling and resulting in significant waste.

[0007] In view of this, the present invention is hereby proposed. Summary of the Invention

[0008] This invention provides an online replacement and cascade regeneration method for waste mineral oil hydrogenation microsphere catalysts. It mainly addresses the problem that in the treatment of deactivated catalysts in fluidized bed reactors, the activity of deactivated catalysts cannot be restored, and impurities such as light carbon deposits, deep coking, and heavy metals on the deactivated catalysts cannot be removed, resulting in the inability to recycle the deactivated catalysts and causing waste.

[0009] To achieve the above objectives, the present invention employs the following technical solution: This invention provides an online replacement and cascade regeneration method for waste mineral oil hydrogenation microsphere catalysts, applicable to a combined hydrogenation process of waste mineral oil fluidized bed-multi-tube fixed bed, comprising the following steps: Monitor parameters, and when the parameters reach the threshold, remove the deactivated microsphere catalyst and simultaneously replenish an equal amount of filling microsphere catalyst; The deactivated microsphere catalyst was washed with a washing solvent, filtered to remove impurities, and then dried. The dried, deactivated microsphere catalyst was subjected to the first stage of low-oxygen, temperature-controlled calcination. The deactivated microsphere catalyst that has undergone the first stage of low-oxygen temperature-controlled calcination is subjected to a second stage of oxygen-enriched high-temperature calcination. After sieving, a regenerated microsphere catalyst is obtained. The regenerated microsphere catalyst is mixed with a fresh microsphere catalyst to obtain a packed microsphere catalyst, thus completing the online replacement and cascade regeneration treatment of the waste mineral oil hydrogenation microsphere catalyst.

[0010] This invention removes impurities from deactivated microsphere catalysts by setting up a first stage of low-temperature controlled calcination and a second stage of oxygen-enriched high-temperature calcination, thereby achieving simultaneous deep decarbonization and removal of heavy metal poisons, and greatly restoring the specific surface area and hydrogenation active sites of the deactivated microsphere catalysts.

[0011] In one specific implementation scheme, the monitoring parameter, when it reaches a threshold, involves removing the deactivated microsphere catalyst and simultaneously replenishing it with an equal amount of fresh microsphere catalyst, which includes the following steps: Monitor the hot spot temperature of the multi-tube fixed-bed reactor connected in series with the fluidized bed reactor. When the hot spot temperature is abnormal and the hot spot temperature drift is greater than or equal to 5°C, 3% to 8% of the total mass of the microsphere catalyst is discharged online and an equal amount of filled microsphere catalyst is added simultaneously.

[0012] In one specific implementation, the washing of the deactivated microsphere catalyst with a washing solvent includes the following steps: The deactivated microsphere catalyst was cooled down, and then the deactivated microsphere catalyst was washed countercurrently with a washing solution; The countercurrent washing temperature is 60℃~90℃, the countercurrent washing pressure is 0.2MPa~0.5MPa, the liquid-solid mass ratio of the washing solution to the deactivated microsphere catalyst is (2~5):1, and the countercurrent washing time is 30min~90min.

[0013] The washing solution is one or a combination of several of the following: n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, toluene, xylene, and light naphtha.

[0014] In one specific implementation, the filtration to remove impurities and drying include the following steps: The washed deactivated microsphere catalyst was subjected to solid-liquid separation under a nitrogen pressure difference of 0.1 MPa to 0.5 MPa using a filter medium with a pore size of 1 to 20 μm to obtain a wet catalyst. The wet catalyst was purged with nitrogen and dried at 80℃~160℃ for 1h~4h to obtain the dried deactivated microsphere catalyst.

[0015] In one specific implementation, the first stage of low-oxygen temperature-controlled calcination of the dried, deactivated microsphere catalyst includes the following steps: Under inert gas protection, the temperature is increased to 350℃~450℃ at a heating rate of 1℃ / min~10℃ / min, and an oxygen-containing gas with a volume concentration of 2%~5% is introduced at a gas hourly space velocity of 500 h⁻¹. -1 ~3000 h -1 Under these conditions, the first stage of low-oxygen temperature-controlled calcination is carried out, with a calcination time of 1 h to 6 h.

[0016] In one specific implementation, the second stage of oxygen-enriched high-temperature calcination of the deactivated microsphere catalyst after the first stage of low-oxygen temperature-controlled calcination includes the following steps: A mixed gas was introduced into the deactivated microsphere catalyst after the first stage of low-oxygen temperature-controlled calcination, and the temperature was increased to 500℃~600℃ at a heating rate of 2℃ / min~10℃ / min, with a gas hourly space velocity of 1000 h⁻¹. -1 ~4000 h -1 Under these conditions, a second stage of oxygen-enriched high-temperature roasting is carried out for 2 h to 8 h, while removing deposited heavy metals. The mixed gas is a mixture of a gaseous chemical complexing agent and an oxygen-enriched gas containing 6% to 21% oxygen by volume. The gas-phase chemical complexing agent is one of acetylacetone vapor, trifluoroacetylacetone vapor, C1-C3 low organic acid vapor, and gas-phase chlorination reagent, and the volume concentration of the chemical complexing agent in the oxygen-enriched gas is 0.1% to 3.0%.

[0017] In this invention, the first stage of low-oxygen, temperature-controlled roasting primarily removes flammable soft coke, but highly crystalline hard coke and deposited heavy metals (such as V, Ni, and Fe) remain deep within the catalyst channels. The second stage of oxygen-enriched, high-temperature roasting increases the oxygen concentration to 6%–21% and the temperature to 500°C–600°C, completely burning off the hard coke. Simultaneously, a gaseous chemical complexing agent introduced with the oxygen-enriched gas diffuses into the pores, undergoing a highly efficient coordination reaction with the exposed heavy metal oxides on the surface to generate volatile metal complexes. These complexes are rapidly desorbed by the exhaust gas under high-temperature gas flow and carried out of the reactor, achieving simultaneous deep decarbonization and heavy metal poisoning removal, significantly restoring the catalyst's specific surface area and hydrogenation active sites.

[0018] In one specific implementation, obtaining the regenerated microsphere catalyst after sieving includes the following steps: The deactivated microsphere catalyst, which has undergone the second stage of oxygen-enriched high-temperature calcination, is passed through a first-stage sieve with a pore size of 150μm to 200μm to remove large particle agglomerates, and then through a second-stage sieve with a pore size of 20μm to 40μm to remove fine dust. Particles with a diameter in the range of 20 μm to 150 μm were collected to obtain regenerated microsphere catalysts.

[0019] In one specific feasible implementation, after filtering out impurities, the following steps are also included: The mixture obtained after washing the deactivated microsphere catalyst with the washing solution is then separated by flash evaporation and recycled for reuse.

[0020] In one specific implementation, the flash separation includes the following steps: The mixture is separated by flash evaporation after being depressurized by throttling. The top vapor separated by flash evaporation is cooled and the gas and light hydrocarbons are recovered. The concentrated catalyst slurry at the bottom is recovered into the washing solution to wash the deactivated microsphere catalyst. The flash separation temperature is 150℃~300℃, and the pressure is 0.1MPa~1.5MPa.

[0021] In one specific implementation, the filled microsphere catalyst is a mixture of regenerated microsphere catalyst and fresh microsphere catalyst in a mass ratio of (1~9):(9~1).

[0022] Compared with the prior art, the present invention has at least the following advantages: 1. This invention employs a staged coking process combined with gas-phase complexation cascade regeneration technology to achieve deep and thorough removal of carbon deposits and heavy metal toxins: This invention overcomes the bottleneck of traditional coke regeneration, which cannot effectively remove heavy metal toxins. First, residual oil is removed by washing with a washing solution. Then, a first-stage low-oxygen, temperature-controlled roasting process prioritizes the removal of light, soft coke, effectively preventing bed overheating and active metal sintering. Next, a second-stage oxygen-rich, high-temperature roasting process burns off the deep, hard coke, while simultaneously introducing a gas-phase chemical complexing agent. This transforms exposed heavy metals (such as V, Ni, and Fe) into volatile complexes for in-situ removal, thoroughly restoring the microporous structure and hydrogenation active sites of the deactivated microsphere catalyst.

[0023] 2. This invention achieves continuous online control and long-term stable operation of the reaction system, avoiding downtime losses: This invention utilizes real-time monitoring of the hot spot temperature and drift (e.g., drift ≥ 5°C) of a multi-tube fixed-bed reactor connected in series with a fluidized bed reactor. It employs an online, batch-by-batch replacement technique to rapidly replenish the overall average catalytic activity of the bed and mitigate hot spot temperature drift without requiring shutdown. While maintaining the optimal process conditions of the fluidized bed reactor, this significantly extends the continuous operation cycle and avoids the substantial economic losses associated with a complete bed shutdown for catalyst replacement.

[0024] 3. This invention possesses a precise particle size distribution control mechanism, enabling high-quality closed-loop recycling of microsphere catalysts: This invention introduces a two-stage sieving process (first-stage sieving and second-stage sieving) to precisely remove fine dust (<20μm) and sintered agglomerates (>150μm) generated during regeneration, ensuring that the particle size distribution (20μm~150μm) and fluidization performance of the regenerated microsphere catalyst are highly matched with those of the fresh catalyst. The regenerated microspheres can be directly recycled back to the reaction system, truly achieving green closed-loop utilization of waste mineral oil hydrogenation catalysts and significantly reducing solid waste emissions and production and operating costs. Attached Figure Description

[0025] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic flowchart of the online replacement and cascade regeneration method for waste mineral oil hydrogenation microsphere catalyst provided by the present invention. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0027] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connection, detachable connection, or integral connection; they can refer to mechanical connection or electrical connection; they can refer to direct connection or indirect connection through an intermediate medium; and they can refer to the connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] To more clearly illustrate the technical solutions in this invention, specific embodiments are described below.

[0030] Example 1 like Figure 1 As shown, this invention provides an online displacement and cascade regeneration method for waste mineral oil hydrogenation microsphere catalysts, which includes the following steps: 1. In the combined hydrogenation process of waste mineral oil fluidized bed-multi-tube fixed bed reactor, the hot spot temperature of the multi-tube fixed bed reactor connected in series with the fluidized bed reactor is monitored in real time. Specifically, the hot spot temperature inside the tube bundle of the multi-tube fixed bed reactor is monitored. When a significant abnormal fluctuation in the hot spot temperature is detected, and the hot spot temperature drift reaches 5.5℃, the deactivated microsphere catalyst is discharged online at 5% of the total metered amount from the discharge hopper at the bottom of the fluidized bed reactor. At the same time, an equal amount of filled microsphere catalyst is added from the top feeder (when there is no filled microsphere catalyst or the amount of filled microsphere catalyst is insufficient, fresh microsphere catalyst can also be added directly).

[0031] Specifically, significant abnormal fluctuations in hot spot temperature refer to at least one of the following situations occurring in the hot spot temperature monitored within the tube bundle of a multi-tube fixed-bed reactor: 1) Abnormal heating rate: The hot spot temperature heating rate is greater than or equal to 0.5℃ / min; 2) Axial hot spot migration: The highest temperature point moves downstream along the tube bundle axis by a distance exceeding 10% of the total bed height; 3) Increased transverse temperature difference between tubes: The maximum temperature difference between different reaction tubes on the same axial cross section is ≥ 5℃; 4) Amplified oscillation: The hot spot temperature exhibits oscillations with an amplitude greater than or equal to ±3℃ around the preset process temperature.

[0032] When the above abnormal fluctuations continue for 5 The above operation is triggered when the hot spot temperature drifts by ≥ 5.5℃ relative to the set reference value after 15 minutes.

[0033] 2. After cooling the discharged deactivated microsphere catalyst, send it into a closed washing tank, pump in the washing solution, and perform countercurrent washing. Control the countercurrent washing time at 75°C, the countercurrent washing pressure at 0.3 MPa, and the countercurrent washing duration at 60 min. The liquid-solid mass ratio of the washing solution to the deactivated microsphere catalyst is 3:1. In this embodiment, the washing solution is selected as n-heptane solution.

[0034] The washed and deactivated microsphere catalyst was fed into a sealed filter, and solid-liquid separation was performed using a filter medium with a pore size of 10 μm under a nitrogen pressure difference of 0.3 MPa to obtain a wet catalyst.

[0035] The wet catalyst was dried at 120°C for 3 hours under nitrogen purging (or under reduced pressure). The residual solvent fraction was less than 1.0%, resulting in a dried deactivated microsphere catalyst.

[0036] Simultaneously, the washed mixture (oil-containing washing solution) is subjected to flash evaporation for separation: The discharged mixture containing the deactivated microsphere catalyst is fed into a flash tank through a throttling and depressurization process. Flash separation is performed at 200°C and 1.0 MPa. The top vapor separated by flash separation is cooled and the recovered gas and light hydrocarbons are collected. The concentrated catalyst at the bottom of the flash tank is remixed with the washing solution to wash the deactivated microsphere catalyst. The heavy residual oil separated by flash separation is sent to the tail oil treatment unit for further processing, or it can be used as a component in asphalt blending.

[0037] 3. The deactivated microsphere catalyst, after washing and removing impurities, undergoes a first-stage low-oxygen temperature-controlled calcination: Under inert gas protection (in this embodiment, nitrogen is selected as the inert gas), an oxygen-deficient mixture with an oxygen volume concentration of 3% is introduced (in this invention, an oxygen-deficient mixture refers to a mixture in which the oxygen supply in the system is significantly lower than the theoretical equivalence ratio required for complete combustion of the carbon deposit. The oxygen volume concentration of the oxygen-deficient mixture is 1%–5%, with the remainder being non-combustion-supporting gases such as nitrogen, carbon dioxide, water vapor, or inert flue gas. In this embodiment, the oxygen volume concentration of the oxygen-deficient mixture is selected as 3%), and the temperature is increased to 400°C at a heating rate of 5°C / min, with a gas hourly space velocity of 2000 h⁻¹. -1 Under controlled temperature conditions, roast for 3 hours.

[0038] 4. The deactivated microsphere catalyst, after the first stage of low-oxygen temperature-controlled calcination, undergoes a second stage of oxygen-enriched high-temperature calcination: A mixed gas (consisting of a gaseous chemical complexing agent (acetylacetone vapor) with a volume concentration of 2% and an oxygen-enriched gas with a volume concentration of 15%) was introduced, and the temperature was increased to 550°C at a heating rate of 8°C / min, with a gas hourly space velocity of 3000 h⁻¹. -1 Under the conditions of high temperature roasting for 4 hours, the heavy metals such as iron and vanadium deposited on the surface are washed away by gas-phase chemical complexing agent.

[0039] It should be noted that the terms "low oxygen," "oxygen-rich," and "high temperature" in this invention are relative to the first stage of low-oxygen temperature-controlled calcination and the second stage of oxygen-rich high-temperature calcination.

[0040] 5. The deactivated microsphere catalyst after the second stage of oxygen-enriched high-temperature calcination is fed into an airflow sieving device or an ultrasonic vibrating screen for two-stage sieving: large particle agglomerates are removed by passing through a first-stage screen with a pore size of 150-200μm, and fine dust is removed by passing through a second-stage screen with a pore size of 20-40μm; microsphere particles with a particle size in the range of 20-150μm are collected, which are the regenerated microsphere catalyst.

[0041] The sieving in this invention can be carried out by airflow sieving or ultrasonic vibration sieving. In this embodiment, ultrasonic vibration sieving is used.

[0042] The regenerated microsphere catalyst and the fresh microsphere catalyst were mixed at a mass ratio of 1:2: The sieved regenerated microsphere catalyst and the fresh microsphere catalyst were added to a closed fluidized bed mixer at a mass ratio of 1:2, and the mixture was purged with dry nitrogen (gas hourly space velocity of 100 h⁻¹). -1 ~500h -1 The gas is suspended in air for 10-20 minutes (in this embodiment, the gas space velocity is selected as 300 h⁻¹). -1 The aerodynamic suspension mixing time was set to 15 minutes to ensure uniform mixing and obtain a well-flowable packed microsphere catalyst. The mixing process was carried out under dry and oxygen-free conditions to prevent the catalyst from absorbing water and moisture.

[0043] The online replacement and cascade regeneration treatment of waste mineral oil hydrogenation microsphere catalysts was completed.

[0044] Example 2-3 The specific implementation method is the same as that in Example 1, except that the conditions are different, as shown in Table 1 below: Table 1 Different reaction conditions Example 4 This embodiment provides an online replacement and cascade regeneration method for waste mineral oil hydrogenation microsphere catalysts, which includes the following steps: 1. During the combined hydrotreating of waste mineral oil, the hot spot temperature of the multi-tube fixed-bed reactor connected in series with the fluidized bed reactor is monitored in real time. Specifically, the hot spot temperature inside the tube bundle of the multi-tube fixed-bed reactor is monitored. When a significant abnormal fluctuation in the hot spot temperature is detected, and the hot spot temperature drift reaches 5°C, the deactivated microsphere catalyst is discharged online at 8% of the total metered amount from the discharge hopper at the bottom of the fluidized bed reactor. At the same time, an equal amount of filled microsphere catalyst is added from the top feeder (when there is no filled microsphere catalyst or the amount of filled microsphere catalyst is insufficient, fresh microsphere catalyst can also be added directly).

[0045] 2. After cooling the discharged deactivated microsphere catalyst, send it into a closed washing tank, pump in the washing solution, and perform countercurrent washing. Control the countercurrent washing time at 85°C, the countercurrent washing pressure at 0.4 MPa, and the countercurrent washing duration at 45 min. The liquid-solid mass ratio of the washing solution to the deactivated microsphere catalyst is 4:1. In this embodiment, the washing solution is selected as n-heptane solution.

[0046] The deactivated microsphere catalyst, after being washed in a sealed washing tank, is filtered out and dried.

[0047] Simultaneously, the washed mixture (oil-containing washing solution) is flash-separated. The washing solution obtained after flash separation is recycled to a closed washing tank for reuse. The heavy residual oil separated by flash separation is sent to the tail oil treatment unit for treatment, or it can be used as an asphalt blending component.

[0048] 3. The deactivated microsphere catalyst, after being washed and free of impurities, undergoes the first stage of low-oxygen temperature-controlled calcination: a lean oxygen mixture with an oxygen volume concentration of 5% is introduced, and the catalyst is calcined at 350℃ for 2 hours.

[0049] 4. The deactivated microsphere catalyst, after the first stage of low-oxygen temperature-controlled calcination, undergoes a second stage of oxygen-enriched high-temperature calcination: oxygen-enriched gas is introduced, and the catalyst is calcined at 550°C for 5 hours, while chemical complexation is used to wash away the heavy metals such as iron and vanadium deposited on the surface.

[0050] 5. The deactivated microsphere catalyst after the second stage of oxygen-enriched high-temperature calcination is screened to obtain regenerated microsphere catalyst. The regenerated microsphere catalyst and fresh microsphere catalyst are mixed at a mass ratio of 1:1 to obtain packed microsphere catalyst, thus completing the online replacement and cascade regeneration treatment of waste mineral oil hydrogenation microsphere catalyst.

[0051] Comparative Example 1 This comparative example uses a conventional offline single-stage calcination regeneration method without n-heptane washing to treat the deactivated microsphere catalyst, which includes the following steps: In the combined hydrogenation process of waste mineral oil fluidized bed-multi-tube fixed bed, the fluidized bed reactor was forced to shut down due to excessive bed pressure drop. After all the deactivated microsphere catalyst in the fluidized bed reactor was removed, it was directly placed in a muffle furnace. Under a conventional air atmosphere (oxygen concentration of 21%), it was directly heated to 600℃ for 5 hours in a single-stage, one-step high-temperature calcination to obtain the regenerated microsphere catalyst.

[0052] Comparative Example 2 This comparative example uses a conventional method for treating deactivated microsphere catalysts without temperature-linked control and elution regeneration defects, which includes the following steps: The conventional pressure drop monitoring method was used for discharging, but the discharging hopper at the bottom of the fluidized bed reactor was not linked to the hot spot temperature inside the tube bundle of the multi-tube fixed bed reactor.

[0053] The deactivated catalyst was washed with ordinary industrial kerosene and then subjected to single-stage air calcination at 500°C for 3 hours to obtain regenerated microsphere catalyst.

[0054] Experimental Example First, the regenerated microsphere catalysts obtained in step (5) of Examples 1-4 and the regenerated microsphere catalysts obtained in Comparative Examples 1-2 were used as samples to test the specific surface area recovery rate, total heavy metal removal rate, and mechanical wear rate (referring to ASTM D4058 standard). The test results are shown in Table 2 below: Table 2 Test Results As can be seen from the data in Table 2, the specific surface area of ​​the regenerated microsphere catalyst prepared by the method provided in this invention can be restored to 86% of that of the fresh microsphere catalyst, the wear rate is 0.4%, and the total removal rate of heavy metals can reach 89.0%. This is much higher than that of the regenerated microsphere catalysts prepared by Comparative Example 1 and Comparative Example 2. This is because in Comparative Example 1, heavy residual oil was not washed off in advance with a washing solution, and the high content of colloids was violently burned at high temperature, causing microscopic local temperature runaway of the deactivated microsphere catalyst. Most of the microsphere skeletons were broken and pulverized, and the wear rate increased sharply to 3.8 wt%. Moreover, the heavy metal impurities were sintered at high temperature and blocked the pores, and the specific surface area was only restored to 42% of that of the fresh catalyst, completely losing its industrial value for re-fluidization and reuse.

[0055] In Comparative Example 2, the discharge lock hopper at the bottom of the fluidized bed reactor was not linked to the hot spot temperature inside the tube bundle of the multi-tube fixed bed reactor. This caused some inferior oil to break through the fluidized bed and undergo local secondary coking in the fixed bed tube bundle. At the same time, the solubility of conventional kerosene was insufficient and single-stage roasting could not completely clean up the deep coking. The specific surface area recovery rate of the final microsphere catalyst was only 55%, which made it very easy to be deactivated again after reuse, which seriously restricted long-term stable operation.

[0056] Table 2 shows that the regenerated microsphere catalysts prepared in this invention achieved a specific surface area recovery rate of over 85%, and the wear rate was strictly maintained below 0.5 wt%, fully meeting the mechanical strength requirements for refluidization in a fluidized bed reactor. In contrast, Comparative Example 1, without elution and direct high-temperature calcination, resulted in violent combustion of high-content colloidal matter, causing microscopic thermal stress concentration in the catalyst, leading to a wear rate as high as 3.85 wt% and severe pulverization, with extremely low heavy metal removal rate; Comparative Example 2, using conventional kerosene solvent and single-stage calcination, failed to remove deep coking in the pores, resulting in poor specific surface area recovery. This further verifies the excellent performance of the online replacement and cascade regeneration method for waste mineral oil hydrogenation microsphere catalysts provided by this invention.

[0057] To verify the recycling effect of the regenerated microsphere catalyst provided by this invention, the filled microsphere catalyst obtained in step (5) of Examples 1-4 and the filled microsphere catalyst obtained by mixing the regenerated microsphere catalyst obtained in Comparative Examples 1-2 with the fresh microsphere catalyst at a mass ratio of 1:2 were used as samples for the waste mineral oil fluidized bed-multi-tube fixed bed combined hydrogenation process. The waste mineral oil feedstock had the following properties: total heavy metal content >150μg / g, and residual carbon content >5%. The focus was on evaluating the protective effect of the discharge linkage logic on the downstream system and the continuous operation cycle of the device. The results are shown in Table 3 below. Table 3 Validation Results As shown in Table 3, this invention, by precisely linking the discharge lock hopper at the bottom of the fluidized bed reactor with the hot spot temperature within the tube bundle of the multi-tube fixed bed reactor, can complete the online renewal of the microsphere catalyst before inferior materials or deactivated powder break through the fluidized bed reactor. This strictly controls the hot spot temperature fluctuation within the tube bundle of the multi-tube fixed bed reactor to within 2°C, completely avoiding secondary coking of the tube bundle. This results in a continuous and stable operating cycle exceeding 3800 hours for the waste mineral oil fluidized bed-multi-tube fixed bed combined hydrogenation process. In contrast, Comparative Example 2, lacking temperature linkage protection, suffered from downstream temperature runaway due to the escape of inferior components, severely restricting the capacity of the entire waste mineral oil hydrogenation unit.

[0058] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. The present invention is not limited to the exact structures described above and illustrated in the accompanying drawings, and it should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various changes and modifications made without departing from the concept of the present invention should be considered to fall within the protection scope of the present invention.

Claims

1. An online replacement and cascade regeneration method for waste mineral oil hydrogenation microsphere catalysts, applied to a waste mineral oil fluidized bed-multi-tube fixed bed combined hydrogenation process, characterized in that... Includes the following steps: Monitor parameters, and when the parameters reach the threshold, remove the deactivated microsphere catalyst and simultaneously replenish an equal amount of filling microsphere catalyst; The deactivated microsphere catalyst was washed with a washing solvent, filtered to remove impurities, and then dried. The dried, deactivated microsphere catalyst was subjected to the first stage of low-oxygen, temperature-controlled calcination. The deactivated microsphere catalyst that has undergone the first stage of low-oxygen temperature-controlled calcination is subjected to a second stage of oxygen-enriched high-temperature calcination. After sieving, a regenerated microsphere catalyst is obtained. The regenerated microsphere catalyst is mixed with a fresh microsphere catalyst to obtain a packed microsphere catalyst, thus completing the online replacement and cascade regeneration treatment of the waste mineral oil hydrogenation microsphere catalyst.

2. The online displacement and cascade regeneration method according to claim 1, characterized in that, The monitoring parameters, when they reach a threshold, involve the following steps: removing the deactivated microsphere catalyst and simultaneously replenishing it with an equal amount of fresh microsphere catalyst. Monitor the hot spot temperature of the multi-tube fixed-bed reactor connected in series with the fluidized bed reactor. When the hot spot temperature is abnormal and the hot spot temperature drift is greater than or equal to 5°C, 3% to 8% of the total mass of the microsphere catalyst is discharged online and an equal amount of filled microsphere catalyst is added simultaneously.

3. The online displacement and cascade regeneration method according to claim 1, characterized in that, The washing of the deactivated microsphere catalyst with a washing solvent includes the following steps: The deactivated microsphere catalyst was cooled down, and then the deactivated microsphere catalyst was washed countercurrently with a washing solution; The countercurrent washing temperature is 60℃~90℃, the countercurrent washing pressure is 0.2MPa~0.5MPa, the liquid-solid mass ratio of the washing solution to the deactivated microsphere catalyst is (2~5):1, and the countercurrent washing time is 30min~90min; The washing solution is one or a combination of several of the following: n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, toluene, xylene, and light naphtha.

4. The online displacement and cascade regeneration method according to claim 3, characterized in that, The filtration to remove impurities and drying process includes the following steps: The washed deactivated microsphere catalyst was subjected to solid-liquid separation under a nitrogen pressure difference of 0.1 MPa to 0.5 MPa using a filter medium with a pore size of 1 to 20 μm to obtain a wet catalyst. The wet catalyst was purged with nitrogen and dried at 80℃~160℃ for 1h~4h to obtain the dried deactivated microsphere catalyst.

5. The online displacement and cascade regeneration method according to claim 1, characterized in that, The first stage of low-oxygen temperature-controlled calcination of the dried, deactivated microsphere catalyst includes the following steps: Under inert gas protection, the temperature is increased to 350℃~450℃ at a heating rate of 1℃ / min~10℃ / min, and an oxygen-containing gas with a volume concentration of 2%~5% is introduced at a gas hourly space velocity of 500 h⁻¹. -1 ~3000 h -1 Under these conditions, the first stage of low-oxygen temperature-controlled calcination is carried out, with a calcination time of 1 h to 6 h.

6. The online displacement and cascade regeneration method according to claim 1, characterized in that, The second stage of oxygen-enriched high-temperature calcination of the deactivated microsphere catalyst after the first stage of low-oxygen temperature-controlled calcination includes the following steps: A mixed gas was introduced into the deactivated microsphere catalyst after the first stage of low-oxygen temperature-controlled calcination, and the temperature was increased to 500℃~600℃ at a heating rate of 2℃ / min~10℃ / min, with a gas hourly space velocity of 1000 h⁻¹. -1 ~4000 h -1 Under these conditions, a second stage of oxygen-enriched high-temperature roasting is carried out for 2 h to 8 h, while removing deposited heavy metals. The mixed gas is a mixture of a gaseous chemical complexing agent and an oxygen-enriched gas containing 6% to 21% oxygen by volume. The gas-phase chemical complexing agent is one of acetylacetone vapor, trifluoroacetylacetone vapor, C1-C3 low organic acid vapor, and gas-phase chlorination reagent, and the volume concentration of the chemical complexing agent in the oxygen-enriched gas is 0.1% to 3.0%.

7. The online displacement and cascade regeneration method according to claim 4, characterized in that, The process of obtaining the regenerated microsphere catalyst after sieving includes the following steps: The deactivated microsphere catalyst, which has undergone the second stage of oxygen-enriched high-temperature calcination, is passed through a first-stage sieve with a pore size of 150μm to 200μm to remove large particle agglomerates, and then through a second-stage sieve with a pore size of 20μm to 40μm to remove fine dust. Particles with a diameter in the range of 20 μm to 150 μm were collected to obtain regenerated microsphere catalysts.

8. The online displacement and cascade regeneration method according to claim 3, characterized in that, After filtering to remove impurities, the following steps are also included: The mixture obtained after washing the deactivated microsphere catalyst with the washing solution is then separated by flash evaporation and recycled for reuse.

9. The online displacement and cascade regeneration method according to claim 2, characterized in that, The flash separation includes the following steps: The mixture is separated by flash evaporation after being depressurized by throttling. The top vapor separated by flash evaporation is cooled and the gas and light hydrocarbons are recovered. The concentrated catalyst slurry at the bottom is recovered into the washing solution to wash the deactivated microsphere catalyst. The flash separation temperature is 150℃~300℃, and the pressure is 0.1MPa~1.5MPa.

10. The online displacement and cascade regeneration method according to claim 1, characterized in that, The filled microsphere catalyst is a mixture of regenerated microsphere catalyst and fresh microsphere catalyst in a mass ratio of (1~9):(9~1).

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