Regeneration method of toluene disproportionation catalyst

Abstract

The invention discloses a method for regenerating a toluene disproportionation catalyst, which is characterized by comprising the following steps of: contacting the toluene disproportionation catalyst to be regenerated with oxygen-containing gas in a rotary roasting kiln for roasting at the roasting temperature of 400-700 DEG C, preferably 550-600 DEG C; the time is 10 to 60 minutes, preferably 30 to 40 minutes. The catalyst is in rapid contact with oxygen in a rotary roasting kiln, the scorching temperature is high, the contact time is short, the inactivated disproportionation reaction catalyst can be effectively and completely activated, and meanwhile the specific surface area of the catalyst is increased.

Description

Technical Field

[0001] This invention relates to a method for regenerating catalysts, and more specifically to a method for regenerating catalysts for toluene disproportionation reactions. Background Technology

[0002] Benzene, toluene, and xylene are important aromatic hydrocarbons, mainly derived from naphtha catalytic reforming products and steam cracking gasoline. However, the xylene products obtained from this process cannot meet the market demand for para-xylene (PX), while toluene and C9+ aromatic hydrocarbon resources are relatively abundant. Therefore, producing benzene and xylene from toluene via a disproportionation process is an effective way to increase xylene production and adjust the aromatic hydrocarbon product structure.

[0003] Currently, the active catalyst components used in industrial toluene disproportionation mainly include mordenite (HM) and ZSM-5 zeolite. Catalyst coking is a common problem in toluene disproportionation reactions, and it is a major cause of decreased catalyst activity or even deactivation. In-situ regeneration (internal regeneration) is typically used to regenerate the catalyst, involving calcination in an oxygen-containing atmosphere to remove the coking deposits from the catalyst surface. However, due to the severe coking and poor high-temperature resistance of this catalyst, the regeneration conditions are extremely demanding. Low-temperature calcination cannot effectively remove the coking deposits, while high-temperature calcination (above 450°C) easily leads to metal migration on the catalyst surface, damaging the catalyst structure and reducing the activity of the regenerated catalyst. Therefore, there are very few patents regarding external regeneration of toluene disproportionation catalysts.

[0004] In 2012, Hou Min et al. disclosed a method for regenerating toluene disproportionation catalyst (CN103657743). The method involves burning deactivated catalyst in an oxygen-containing atmosphere to produce a gaseous mixture, which is then divided into two parts. The concentrations of carbon monoxide and carbon dioxide in the regeneration atmosphere are detected separately, which can promptly determine the degree of regeneration of toluene disproportionation catalyst and can be used in the industrial production of toluene disproportionation catalyst regeneration. Summary of the Invention

[0005] The purpose of this invention is to provide a regeneration method for toluene disproportionation catalyst that is completely different from the prior art. This method can fully activate the deactivated disproportionation catalyst while ensuring the crystallinity of the catalyst, and at the same time increase the specific surface area of ​​the catalyst.

[0006] Currently, acidic molecular sieves are commonly used as catalysts for the toluene disproportionation reaction. These acidic molecular sieves are actually crystalline microporous aluminosilicates, whose basic framework structure is based on a rigid three-dimensional TO4 (SiO4, AlO4, etc.) unit structure. In this structure, TO4 atoms share oxygen atoms in a tetrahedral manner, and the charge balance of the framework tetrahedra, such as AlO4, is achieved through surface cations such as Na. + H +The existence of these pores is maintained. At the same time, the structure of molecular sieves contains a rich system of channels with specific pore sizes, which interweave to form a three-dimensional network structure.

[0007] Acidic molecular sieves gradually deactivate during use, and many factors contribute to this deactivation, such as catalyst poisons present in the reactants, including basic nitrogen compounds and sulfur-containing compounds. Catalyst poisons can react with the acidic sites of the catalyst, leading to the deactivation of active components or restricting access to active components within the catalyst structure. Catalyst poisons can further reduce yield and increase cost. Additionally, as the reaction continues, low C / H ratio coke precursors deposit on the catalyst surface. The continuous accumulation of these substances can clog catalyst pores or occupy active sites, resulting in a gradual decrease in catalyst activity.

[0008] Due to the inherent structural characteristics of toluene disproportionation catalysts, regeneration conditions are extremely demanding, and their high-temperature resistance is poor. Excessively high processing temperatures can lead to the collapse of the molecular sieve framework or metal migration from the catalyst surface, thus affecting the recovery of catalyst activity during regeneration.

[0009] Through extensive experimentation, the inventors discovered that using a rotary roasting furnace to subject the deactivated disproportionated catalyst to instantaneous contact treatment followed by high-temperature coking can effectively improve the uniformity of catalyst surface temperature compared to existing processes. Simultaneously, it shortens catalyst regeneration time, reduces the damage to the catalyst structure caused by high-temperature treatment, increases the specific surface area of ​​the catalyst, and restores the catalyst's activity to its initial level. Based on this, the present invention was developed.

[0010] This invention provides a method for regenerating a toluene disproportionation catalyst, the method comprising: roasting the to be-regenerated toluene disproportionation catalyst in a rotary roasting furnace with an oxygen-containing gas, the roasting temperature being 400-700℃, preferably 550-600℃, and the roasting time being 10-60 min, preferably 30-40 min.

[0011] According to the present invention, oxygen-containing gas is preferably expressed as oxygen (m). 3 The ratio of the catalyst to the toluene disproportionation catalyst (kg) is 1 to 10:1; preferably 3 to 4:1. By adopting the aforementioned preferred embodiment, the uniformity of the catalyst surface temperature can be effectively improved, while shortening the catalyst regeneration time, reducing the damage to the catalyst structure caused by high-temperature treatment, increasing the specific surface area of ​​the catalyst, and restoring the catalyst activity to its initial activity.

[0012] This invention is applicable to deactivated disproportionation catalysts from various sources, illustrated by way of example but not limiting the scope of the invention. According to the invention, the deactivated disproportionation catalyst is preferably a deactivated disproportionation catalyst from the reaction of toluene and C9 aromatics to prepare xylene.

[0013] This invention is applicable to deactivated disproportionation catalysts of various properties. The examples are illustrative but do not limit the scope of the invention. According to the invention, a preferred deactivated disproportionation catalyst, i.e., the toluene disproportionation catalyst to be generated as described in this invention, has the following characteristics: carbon content of 1-25%, preferably 18-22% by weight; specific surface area of ​​100-350 m² / g. 2 / g, preferably 150-160m 2 / g; pore volume is 0.1-0.36 mL / g, preferably 0.15-0.17 mL / g.

[0014] This invention is suitable for disproportionation catalysts after deactivation of various structures. It is illustrative but does not limit the scope of the invention. According to the invention, preferably, one or more of the disproportionation catalysts selected from HM structure molecular sieves, ZSM-5 type molecular sieves or EU-1 molecular sieves are used as the catalyst active component.

[0015] The present invention does not have special requirements for the structure of the rotary roasting kiln. According to the present invention, the preferred operating parameters of the rotary roasting kiln include: the thickness of the toluene disproportionation catalyst to be produced is 1-2 cm, the diameter is 1 m-2 m, there is a material lifting baffle on the inner wall, the shape of the material lifting baffle is a spiral line (the fastest descent line), and the rotation speed is 1-10 rpm.

[0016] In this invention, there are no special requirements for the length of the material feeding baffle, nor for the distance between the centers of the two baffles. In the embodiment, the baffle length is 10cm, the center points are arranged in a regular hexagon, and the distance between the centers of the two baffles is 20cm, which serves as an example to illustrate the advantages of this invention.

[0017] According to the present invention, the calcination is preferably carried out under conditions where the toluene disproportionation catalyst is adsorbed with pyridine and / or aniline, wherein the amount of pyridine and / or aniline is 10-100 g / kg catalyst, preferably 40-60 g / kg catalyst, and preferably both pyridine and aniline are adsorbed simultaneously, with a mass ratio of pyridine to aniline of 0.1-0.5:1. The aforementioned preferred embodiments can more effectively improve the uniformity of catalyst surface temperature, while shortening the catalyst regeneration time, reducing the damage to the catalyst structure caused by high-temperature treatment, increasing the specific surface area of ​​the catalyst, and restoring the catalyst activity to its initial activity.

[0018] In this invention, in order to ensure that pyridine and / or aniline are adsorbed as uniformly as possible with the catalyst, a high-speed mixing device can be used for mixing, or an aqueous solution can be prepared in advance for thorough mixing, followed by drying to obtain a uniformly adsorbed solid for regeneration. For example, an aqueous solution with a concentration of 0.5-2wt% can be prepared for premixing. To ensure thorough mixing, it can be thoroughly mixed at 80-100℃ for 1-3 hours, and then dried until the mass remains unchanged before being sent to a rotary kiln for processing.

[0019] According to a more preferred embodiment of the present invention, the preferred calcination conditions include: holding at 400-600°C for 5-20 min; preferably at 500°C for 10 min; followed by holding at 500-700°C for 20-30 min, preferably at 560°C for 25 min. The aforementioned preferred embodiments can more effectively improve the uniformity of catalyst surface temperature, while shortening the catalyst regeneration time, reducing the damage to the catalyst structure caused by high-temperature treatment, increasing the specific surface area of ​​the catalyst, and restoring the catalyst activity to its initial activity.

[0020] In this invention, there are no special requirements for the oxygen-containing gas. According to this invention, the oxygen-containing gas preferably comprises: an oxygen content of 20-50%v%, with the remainder being inert gases.

[0021] In this invention, the calcination is preferably carried out in the presence of water vapor, the amount of water vapor being measured by volume (m³). 3 The ratio of the catalyst to the toluene disproportionation catalyst (kg) is 1 to 4:1; preferably 2 to 3:1. This allows for better recovery of the catalyst's initial activity, ensuring its complete restoration.

[0022] like Figure 1 , Figure 2 As shown, Figure 1 This is a front view of a rotary kiln according to one embodiment of the present invention; Figure 2 The left view of a rotary kiln according to an embodiment of the present invention includes a kiln body and a baffle plate disposed inside the kiln body.

[0023] In this invention, the rotary roasting kiln has a diameter of, for example, 1-2 meters, and has baffles on its inner wall to ensure sufficient contact between the catalyst material and the combustion-supporting fuel during roasting. This also reduces the contact time between the catalyst and the kiln's inner wall, minimizing the damage to the catalyst structure caused by high temperatures. The roasting temperature is 400-700°C, with a preferred contact temperature of 550-600°C. The contact time is 10-60 minutes, with a preferred contact time of 30-40 minutes. During the contact, the combustion-supporting fuel is oxygen, with a gas-to-fuel ratio of 1-10, and a preferred flow rate of 3-4.

[0024] In this invention, the rotary kiln has no special requirements for rotation speed. For example, the rotation speed is 1 to 10 rpm, preferably 2 to 5 rpm, such as 2 rpm, 3 rpm, 4 rpm, or 5 rpm.

[0025] The regeneration method provided by this invention is particularly suitable for the regeneration of toluene disproportionation catalysts. In the disproportionation catalyst, one or more molecular sieves selected from ZSM-5, HM, and EU-1 are used as the active catalyst component. As mentioned earlier, toluene disproportionation catalysts gradually deactivate during use due to carbon buildup or other impurities clogging the pores, resulting in a decreasing number of active centers and a slow decline in toluene conversion rate, necessitating regeneration.

[0026] Considering the recovery effect of the specific surface area of ​​the catalyst after regeneration, the preferred regeneration temperature is 550–600°C. The inventors unexpectedly discovered that, according to the method of this invention, when the contact time is 30–40 minutes, the regeneration effect is even better, with minimal damage to the catalyst structure, and the specific surface area and pore volume of the catalyst are both increased by 10% compared to the regeneration effect of a single substance.

[0027] In the regeneration method provided by this invention, the step of instantaneously contacting the disproportionation catalyst with the rotary roasting kiln helps to improve the accessibility of the molecular sieve catalyst pore structure, increase the specific surface area and pore volume of the catalyst, thereby better restoring the initial activity of the catalyst and enabling the initial activity of the catalyst to be fully restored.

[0028] This invention enables rapid contact with oxygen in a rotary kiln, resulting in high coking temperature and short contact time, which effectively reactivates the deactivated disproportionation catalyst and increases its specific surface area. Attached Figure Description

[0029] Figure 1 This is a front view of a rotary kiln according to one embodiment of the present invention; Figure 2 This is a left view of a rotary kiln according to one embodiment of the present invention. Detailed Implementation

[0030] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0031] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by one of ordinary skill in the art. In case of conflict, the definitions in this specification shall prevail.

[0032] In the context of this specification, any two or more aspects of the present invention may be combined arbitrarily, and the resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0033] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless being based on weight would not be in accordance with the common understanding of those skilled in the art.

[0034] The present invention will be further illustrated by the following examples, but these examples do not limit the scope of the invention.

[0035] In the examples, the specific surface area and pore volume of the catalyst were determined by nitrogen low-temperature physical adsorption (BET method), and the carbon content was determined by an infrared carbon-sulfur analyzer.

[0036] In the examples, the disproportionation catalyst A (the active component is HM molecular sieve, with a carbon content of 21.1% and a specific surface area of ​​150 m²) 2 / g, pore volume is 0.15 mL / g); In the examples, the undeveloped disproportionation catalyst B (the active component is ZSM-5 molecular sieve, with a carbon content of 19.6% and a specific surface area of ​​160 m²) 2 / g, pore volume is 0.17 mL / g). Both the disproportionation catalysts A and B are deactivated disproportionation catalysts from the reaction of toluene and C9 aromatics to prepare xylene.

[0037] The following embodiments employ the following methods: Figure 1 The rotary kiln shown is used for catalyst regeneration. Its specific structure includes a rotary kiln body and scraping baffles. The scraping baffles are fixed to the inner wall of the rotary kiln, with a length of 10cm and their center points arranged in a regular hexagonal pattern. The distance between the centers of two baffles is 20cm, and the diameter of the rotary kiln is 1.5m. The cross-sectional shape of the baffles is a spiral curve (brachial descent curve).

[0038] Example 1 The temperature of the rotary roasting kiln was controlled at 560℃. After the temperature stabilized, the rotation speed of the rotary roasting kiln was set (3 rpm) to make the roasting time 30 min. Oxygen (pure oxygen) was introduced to keep the gas-catalyst mass ratio at 3:1. Then, the deactivated disproportionating catalyst A was continuously added into the rotary roasting kiln, and the catalyst accumulation thickness was controlled at 2 cm. The regenerated catalyst was discharged from the outlet to obtain catalyst A1.

[0039] The specific surface area and pore volume of catalyst A1 were determined. The analytical results are listed in Table 1.

[0040] Comparative Example 1 Comparative Example 1 illustrates the conventional roasting and regeneration process in the prior art.

[0041] Calcination: The catalyst A to be regenerated was placed in a mesh belt kiln, and oxygen (pure oxygen) was introduced to maintain the gas-catalyst mass ratio at 3:1. Calcination was carried out at 450℃ for 24 hours to obtain catalyst DB-A. The specific surface area and pore volume of the catalyst were measured. The analytical results are listed in Table 1.

[0042] Example 2 The temperature of the rotary roasting kiln was controlled at 500℃. After the temperature stabilized, the rotation speed of the rotary roasting kiln was set (3 rpm) to make the roasting time 30 min. Oxygen (pure oxygen) was introduced to keep the gas-catalyst mass ratio at 3:1. Then, the deactivated disproportionation catalyst A was continuously added into the rotary roasting kiln, and the catalyst accumulation thickness was controlled at 2 cm. The regenerated catalyst was discharged from the outlet to obtain catalyst A2.

[0043] The specific surface area and pore volume of catalyst A2 were determined. The analytical results are listed in Table 1.

[0044] Example 3 The temperature of the rotary roasting kiln was controlled at 650℃. After the temperature stabilized, the rotation speed of the rotary roasting kiln was set (3 rpm) to make the roasting time 30 min. Oxygen (pure oxygen) was introduced to keep the gas-catalyst mass ratio at 3:1. Then, the deactivated disproportionation catalyst A was continuously added into the rotary roasting kiln, and the catalyst accumulation thickness was controlled at 2 cm. The regenerated catalyst was discharged from the outlet to obtain catalyst A3.

[0045] The specific surface area and pore volume of catalyst A3 were determined. The analytical results are listed in Table 1.

[0046] Example 4 The temperature of the rotary roasting kiln was controlled at 560℃. After the temperature stabilized, the rotation speed of the rotary roasting kiln was set (3 rpm) to make the roasting time 10 min. Oxygen (pure oxygen) was introduced to keep the gas-catalyst mass ratio at 3:1. Then, the deactivated disproportionation catalyst A was continuously added into the rotary roasting kiln, and the catalyst accumulation thickness was controlled at 2 cm. The regenerated catalyst was discharged from the outlet to obtain catalyst A4.

[0047] The specific surface area and pore volume of catalyst A4 were determined. The analytical results are listed in Table 1.

[0048] Example 5 The temperature of the rotary roasting kiln was controlled at 560℃. After the temperature stabilized, the rotation speed of the rotary roasting kiln was set (3 rpm) to make the roasting time 60 min. Oxygen (pure oxygen) was introduced to keep the gas-catalyst mass ratio at 3:1. Then, the deactivated disproportionating catalyst A was continuously added into the rotary roasting kiln, and the catalyst accumulation thickness was controlled at 2 cm. The regenerated catalyst was discharged from the outlet to obtain catalyst A5.

[0049] The specific surface area and pore volume of catalyst A5 were determined. The analytical results are listed in Table 1.

[0050] Example 6 The temperature of the rotary roasting kiln was controlled at 560℃. After the temperature stabilized, the rotation speed of the rotary roasting kiln was set (3 rpm) to make the roasting time 30 min. Oxygen (pure oxygen) was introduced to keep the gas-to-catalyst ratio at 1:1. Then, the deactivated disproportionating catalyst A was continuously added into the rotary roasting kiln, and the catalyst accumulation thickness was controlled at 2 cm. The regenerated catalyst was discharged from the outlet to obtain catalyst A6.

[0051] The specific surface area and pore volume of catalyst A6 were determined. The analytical results are listed in Table 1.

[0052] Example 7 The temperature of the rotary roasting kiln was controlled at 560℃. After the temperature stabilized, the rotation speed of the rotary roasting kiln was set (3 rpm) to make the roasting time 30 min. Oxygen (pure oxygen) was introduced to keep the gas-catalyst mass ratio at 10:1. Then, the deactivated disproportionation catalyst A was continuously added into the rotary roasting kiln, and the catalyst accumulation thickness was controlled at 2 cm. The regenerated catalyst was discharged from the outlet to obtain catalyst A7.

[0053] The specific surface area and pore volume of catalyst A7 were determined. The analytical results are listed in Table 1.

[0054] Example 8 The temperature of the rotary roasting kiln was controlled at 560℃. After the temperature stabilized, the rotation speed of the rotary roasting kiln was set (3 rpm) to make the roasting time 30 min. Oxygen (pure oxygen) was introduced to keep the gas-catalyst mass ratio at 3:1. Then, the deactivated disproportionation catalyst B was continuously added into the rotary roasting kiln, and the catalyst accumulation thickness was controlled at 2 cm. The regenerated catalyst was discharged from the outlet to obtain catalyst B1.

[0055] The specific surface area and pore volume of the catalyst were determined. The analytical results are listed in Table 1.

[0056] Comparative Example 2 This comparative example illustrates the conventional roasting and regeneration process.

[0057] Calcination: The toluene disproportionation catalyst B to be produced is placed in a mesh belt kiln, oxygen (pure oxygen) is introduced to maintain the gas-catalyst mass ratio at 3:1, and calcined at 550℃ for 24 hours to obtain catalyst DB-B.

[0058] The specific surface area and pore volume of the catalyst were determined. The analytical results are listed in Table 1.

[0059] Example 9 The temperature of the rotary roasting kiln was controlled at 560℃. After the temperature stabilized, the rotation speed of the rotary roasting kiln was set (3 rpm) to make the roasting time 50 min. Oxygen (pure oxygen) was introduced to keep the gas-catalyst mass ratio at 3:1. Then, the deactivated disproportionation catalyst B was continuously added into the rotary roasting kiln, and the catalyst accumulation thickness was controlled at 2 cm. The regenerated catalyst was discharged from the outlet to obtain catalyst B2.

[0060] The specific surface area and pore volume of catalyst B2 were determined. The analytical results are listed in Table 1.

[0061] Example 10 The method is the same as in Example 8, except that the catalyst to be produced is treated with pyridine before being fed into the rotary kiln for calcination, with the amount of pyridine being 50 g / kg of catalyst. 1 m³ of the solution is prepared according to the specified ratio. 3 A 1% pyridine aqueous solution was poured into a reactor, along with 500 kg of the catalyst to be generated. Stirring was started, and the temperature was raised. The mixture was kept constant at 95±5℃ for 120 minutes, after which stirring was stopped. The catalyst was washed twice with clean water, filtered, and dried. It was then sent to a rotary kiln for further processing to obtain catalyst B3.

[0062] The specific surface area and pore volume of catalyst B3 were determined. The analytical results are listed in Table 1.

[0063] Example 11 The method was followed in Example 8, except that the temperature of the rotary roasting kiln was controlled in stages. The temperature of the first stage was controlled at 500°C for 10 minutes; the temperature of the second stage was controlled at 560°C for 25 minutes. The rotation speed of the rotary roasting kiln was set to 3 revolutions / min, and catalyst B4 was obtained after regeneration.

[0064] The specific surface area and pore volume of catalyst B4 were determined. The analytical results are listed in Table 1.

[0065] Example 12 The method is the same as in Example 8, except that the concentration of oxygen in the combustion-supporting gas is 45%, with the remainder being nitrogen. Catalyst B5 is obtained after regeneration.

[0066] The specific surface area and pore volume of catalyst B5 were determined. The analytical results are listed in Table 1.

[0067] Example 13 The method is the same as in Example 8, except that a small amount of water vapor is added during the roasting process, by volume (m). 3 The ratio of the amount of catalyst B6 to the amount of toluene disproportionation catalyst (kg) was 2:1, thus obtaining catalyst B6.

[0068] The specific surface area and pore volume of catalyst B6 were determined. The analytical results are listed in Table 1.

[0069] Example 14 The method is the same as in Example 10, except that a small amount of water vapor is added during the roasting process, by volume (m³). 3 The ratio of oxygen to toluene disproportionation catalyst (kg) was 2:1. The oxygen concentration in the combustion-supporting gas was 45%, with the remainder being nitrogen. The temperature of the rotary kiln was controlled in stages. The first stage temperature was controlled at 500℃ for 10 min, and the second stage temperature was controlled at 560℃ for 25 min. The rotation speed of the rotary kiln was set to 3 rpm.

[0070] Example 15 The method is the same as in Example 8, except that the calcination temperature is 600°C and the time is 40 minutes.

[0071] Example 16 The method of Example 14 is followed, except that pyridine and aniline are used as a co-adsorption catalyst with a mass ratio of pyridine to aniline of 0.3:1 and an amount of pyridine and aniline of 50 g / kg catalyst. Specifically, the method of Example 10 is followed for the pre-adsorption of pyridine and aniline.

[0072] Test case The regenerated catalyst samples from the examples and comparative examples were used in the toluene disproportionation reaction.

[0073] The catalyst sample was ground into 20-40 mesh particles, and 60 mL was loaded into a stainless steel reactor (stainless steel tubular isothermal reaction tube, inner diameter 22 mm, catalyst loading 60 mL). After purging with nitrogen at 110 °C, toluene and C9 aromatics (mass ratio of toluene to C9 aromatics 6:4) were introduced. The C9 aromatics included propylbenzene and ethylbenzene, etc. The volumetric hourly space velocity of the feed liquid was 3 h⁻¹. -1 The reaction pressure was 2.1 MPa. After stabilization at 360℃ for 48 hours, the material balance of the device was performed, and the liquid recovery was over 96%. Samples were taken for chromatographic analysis. The disproportionation reaction results are shown in Table 1.

[0074] Table 1 The total conversion rate of disproportionation is calculated as follows: (total amount of toluene and C9 aromatics in reactants - total amount of toluene and C9 aromatics in products) / total amount of toluene and C9 aromatics in reactants; The total selectivity of xylene is calculated as: xylene production / (total amount of toluene and C9 aromatics in reactants - total amount of toluene and C9 aromatics in products).

[0075] The embodiments described above are merely illustrative of the detailed process of the present invention, but the present invention is not limited to the above-described process; that is, the present invention can be implemented without relying on the steps described in the above embodiments. In summary, any improvements made to the present invention by those skilled in the art, including substitutions for the raw materials and additives described in the present invention, and selections of specific implementation methods, are all within the scope of protection and disclosure of the present invention.

Claims

1. A method for regenerating a toluene disproportionation catalyst, characterized in that, The method includes: roasting the toluene disproportionation catalyst in a rotary roasting furnace by contacting it with an oxygen-containing gas at a temperature of 400–700°C, preferably 550–600°C, for a time of 10–60 min, preferably 30–40 min.

2. The regeneration method according to claim 1, wherein, Oxygen-containing gas is expressed as oxygen (m³ / s). 3 The ratio of the catalyst to the toluene disproportionation catalyst (kg) is 1 to 10:1; preferably 3 to 4:

1.

3. The regeneration method according to claim 1 or 2, wherein, The aforementioned toluene disproportionation catalyst is the deactivated disproportionation catalyst obtained from the reaction of toluene and C9 aromatics to prepare xylene.

4. The regeneration method according to any one of claims 1-3, wherein, The toluene disproportionation catalyst to be produced has a carbon content of 1-25% by weight, preferably 18-22% by weight; and a specific surface area of ​​100-350 m². 2 / g, preferably 150-160m 2 / g; pore volume is 0.1-0.36 mL / g, preferably 0.15-0.17 mL / g.

5. The regeneration method according to any one of claims 1-4, wherein, In the disproportionation catalyst, one or more of the following are selected as catalyst active components: HM structure molecular sieve, ZSM-5 type molecular sieve or EU-1 molecular sieve.

6. The regeneration method according to any one of claims 1-5, wherein, The operating parameters of the rotary roasting kiln include: the thickness of the toluene disproportionation catalyst to be produced is 1-2 cm, the diameter is 1-2 m, there are material-lifting baffles on the inner wall, the shape of the material-lifting baffles is a spiral line (the fastest descent line), and the rotation speed is 1-10 rpm.

7. The regeneration method according to any one of claims 1-6, wherein, The calcination is carried out under the condition that the toluene disproportionation catalyst adsorbs pyridine and / or aniline. The amount of pyridine and / or aniline is 10-100 g / kg catalyst, preferably 40-60 g / kg catalyst. It is preferred that pyridine and aniline are adsorbed simultaneously, and the mass ratio of pyridine to aniline is 0.1-0.5:

1.

8. The regeneration method according to any one of claims 1-7, wherein, The roasting process includes: holding at 400-600℃ for 5-20 minutes; preferably at 500℃ for 10 minutes; then raising the temperature to 500-700℃ and holding for 20-30 minutes, preferably at 560℃ for 25 minutes.

9. The regeneration method according to claim 1 or 2, wherein, The oxygen-containing gas composition includes: 20-50% oxygen content, with the remainder being inert gases.

10. The regeneration method according to claim 1 or 2, wherein, The calcination is carried out in the presence of steam, the amount of steam being measured by volume (m³). 3 The ratio of the catalyst to the toluene disproportionation catalyst (kg) is 1 to 4:1; preferably 2 to 3:1.

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