Regeneration method for enhancing particle strength of deactivated catalyst for preparing maleic anhydride through oxidation of n-butane

Abstract

The invention relates to the field of regeneration of a deactivated catalyst for preparing maleic anhydride through oxidation of n-butane, and discloses a regeneration method for enhancing the particle strength of the deactivated catalyst for preparing maleic anhydride through oxidation of n-butane. The method comprises the following steps: carrying out first regeneration and second regeneration on a deactivated catalyst for preparing maleic anhydride by oxidizing n-butane; wherein the first regeneration atmosphere is inert gas; wherein the second regeneration atmosphere is at least one of alcohol steam, water vapor, inert gas and air. By adopting the method, the activity of the deactivated catalyst is greatly improved, the particle strength of the deactivated catalyst is also improved, and the cost is reduced and the efficiency is improved for stable operation of a device.

Description

Technical Field

[0001] The invention relates to the field of regeneration of deactivated catalysts for preparing maleic anhydride by oxidation of n-butane, and in particular to a regeneration method for enhancing the strength of deactivated catalyst particles for preparing maleic anhydride by oxidation of n-butane. Background Art

[0002] The oxidation of n-butane to produce maleic anhydride (maleic anhydride for short) is a highly exothermic, high value-added catalytic conversion process and one of the most significant industrial applications. Its downstream products are very rich, such as γ-butyrolactone, fumarate, unsaturated polyester resin, etc. As an important intermediate, maleic anhydride has very important applications in the fields of fine chemicals such as food, medicine, pesticides, construction, and new materials, and is an important basic material for biodegradable plastics, with huge market demand in the future. However, due to the large number of side reactions in the catalytic conversion process of butane, the requirements for catalysts in the process of butane oxidation to produce maleic anhydride are extremely high. At present, only VPO catalyst has achieved industrial production, but its high price and high technical barriers have greatly increased the investment of maleic anhydride manufacturers in catalysts. During the long-term operation of VPO industrial catalysts (usually 3-5 years), the catalyst activity decreases significantly and the strength decreases. Catalyst pulverization can cause catalyst pipe blockage and increase the pressure drop in the tower, greatly increasing the energy consumption and operating cost of the device. The recovery process of VPO deactivated catalyst in the prior art is complex and expensive, and causes great pollution and waste. Summary of the invention

[0003] The purpose of the present invention is to overcome the problems existing in the prior art and provide a regeneration method for enhancing the strength of deactivated catalyst particles for the production of maleic anhydride by oxidation of n-butane. The method greatly improves the activity of the deactivated catalyst and increases its particle strength, thereby reducing costs and increasing efficiency for the stable operation of the device.

[0004] In order to achieve the above object, the present invention provides a method for regenerating a deactivated catalyst for preparing maleic anhydride by oxidation of n-butane, the method comprising the following steps: performing a first regeneration and a second regeneration on the deactivated catalyst for preparing maleic anhydride by oxidation of n-butane;

[0005] Wherein, the first regeneration atmosphere is an inert gas;

[0006] Wherein, the second regeneration atmosphere is alcohol vapor, and at least one of water vapor, inert gas and air.

[0007] Through the above technical solution, the beneficial effects of the present invention include:

[0008] Through the regeneration method provided by the present invention, the inactive phase of the deactivated catalyst can be effectively converted back into the active phase by adopting a two-stage regeneration process, greatly improving the activity of the deactivated catalyst, and also increasing the strength of the deactivated catalyst particles, effectively reducing the degree of catalyst pulverization under long-term operation, and reducing costs and increasing efficiency for the stable operation of the device. Preferably, the catalyst is regenerated by an online method without disassembling the catalyst, which is simple to operate, saves time and effort, is easy to operate, does not require large-scale transformation of industrial equipment, and reduces labor costs and safety risks. DETAILED DESCRIPTION

[0009] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0010] In the present invention, the "first", "second" and "third" do not limit the substances and operations, but are only used to distinguish the substances introduced in different steps and the operations performed in different stages.

[0011] In the present invention, the "room temperature" refers to 20-40°C.

[0012] In one aspect, the present invention provides a method for regenerating a deactivated catalyst for preparing maleic anhydride by oxidation of n-butane, the method comprising the following steps: performing a first regeneration and a second regeneration on the deactivated catalyst for preparing maleic anhydride by oxidation of n-butane;

[0013] Wherein, the first regeneration atmosphere is an inert gas;

[0014] Wherein, the second regeneration atmosphere is alcohol vapor, and at least one of water vapor, inert gas and air.

[0015] After a long period of operation (generally 3-5 years), the catalyst for the oxidation of n-butane to produce maleic anhydride is deactivated. Compared with the fresh catalyst, the catalyst activity is seriously reduced, and the deactivated catalyst also has a decrease in particle strength and particle pulverization, which leads to catalyst pipe blockage and increased pressure drop in the tower, greatly increasing the energy consumption and operating cost of the device. The inventors of the present invention have found that the first regeneration using the first regeneration atmosphere as an inert gas and the second regeneration atmosphere as an alcohol vapor, as well as the synergistic effect of the second regeneration of at least one of water vapor, inert gas and air, can greatly improve the activity of the deactivated catalyst and the particle strength, thereby reducing costs and increasing efficiency for the stable operation of the device.

[0016] In the present invention, when the n-butane oxidation to maleic anhydride reacts at 420°C and the maleic anhydride mass yield is less than 80% or the molar yield is less than 50%, it can be considered that the catalyst is deactivated and is not suitable for continued production, and the particle strength is less than 40N, requiring regeneration and strengthening of the particle strength.

[0017] The present invention has a wide range of selections for the inert gas, which can be conventionally selected in the art. Preferably, the inert gas is selected from at least one of nitrogen, argon, helium and neon, preferably nitrogen.

[0018] According to the present invention, preferably, the volume space velocity of the first regeneration atmosphere is 300-2000h -1 , preferably 800-1500h -1 The use of this preferred embodiment is conducive to preventing the catalyst from further pulverizing.

[0019] In order to improve the particle strength and activity of the deactivated catalyst, preferably, in the second regeneration atmosphere, the volume content of alcohol vapor is 0.1-5%, for example, it can be 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% and any value in the range formed by any two of these point values; the volume content of water vapor is 0-50%, for example, it can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% and any value in the range formed by any two of these point values. The volume content of the inert gas is 0-80%, for example, it can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 65%, 70%, 75%, 80% and any value in the range formed by any two of these point values; the volume content of the air is 0-45%, for example, it can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% and any value in the range formed by any two of these point values.

[0020] Preferably, the second regeneration atmosphere is alcohol vapor, and at least two of water vapor, inert gas and air. For example, it can be a combination of alcohol vapor, water vapor and air, a combination of alcohol vapor, water vapor and inert gas, or a combination of alcohol vapor, inert gas and air.

[0021] According to the present invention, it is particularly preferred that the second regeneration atmosphere is alcohol vapor, water vapor, inert gas and air. This preferred embodiment is beneficial to further improve the particle strength and activity of the deactivated catalyst.

[0022] In order to further improve the particle strength and activity of the deactivated catalyst, preferably, in the second regeneration atmosphere, the volume content of alcohol vapor is 1-3.5%, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5% and any value in the range formed by any two of these point values; the volume content of water vapor is 10-35%, for example, it can be 10%, 15%, 20%, 25%, 30%, 35% and any value in the range formed by any two of these point values; the volume content of the inert gas is 40-80%, for example, it can be 40%, 45%, 50%, 60%, 65%, 70%, 75%, 80% and any value in the range formed by any two of these point values; the volume content of air is 8-30%, for example, it can be 8%, 10%, 15%, 20%, 25%, 30% and any value in the range formed by any two of these point values.

[0023] According to the present invention, preferably, the volume space velocity of the second regeneration atmosphere is 300-2000h -1 , preferably 800-1500h -1 The use of this preferred embodiment is further beneficial to enhancing the strength of the catalyst particles while improving the catalyst activity.

[0024] According to the present invention, preferably, the alcohol vapor is selected from C 1 -C 4 The alcohol is preferably at least one selected from ethanol, isopropanol and isobutanol.

[0025] Further preferably, the alcohol vapor is isobutanol, ethanol and / or isopropanol.

[0026] According to the present invention, preferably, the volume ratio of isobutanol to ethanol and / or isopropanol is 1:0.3-1, for example, it can be 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1 and any value in the range formed by any two of these point values.

[0027] The use of the specific type of alcohol vapor in the above specific ratio is beneficial to further improve the particle strength of the catalyst.

[0028] According to the present invention, preferably, the first regeneration comprises: heating the deactivated catalyst from room temperature to a first regeneration temperature in a first regeneration atmosphere, and then performing a first constant temperature maintenance.

[0029] According to the present invention, preferably, the first regeneration temperature is 380-450°C, preferably 380-430°C; the first constant temperature holding time is 0-8h, preferably 0-5h.

[0030] According to the present invention, preferably, the heating rate of heating to the first regeneration temperature is 0.1-10°C / min, preferably 0.1-7°C / min.

[0031] The present invention adopts the above-mentioned specific first regeneration process, which is beneficial to the stability of the catalyst structure and strength.

[0032] According to the present invention, preferably, the second regeneration condition includes: in a second regeneration atmosphere, subjecting the first regeneration product to a second constant temperature maintenance at a second regeneration temperature.

[0033] According to the present invention, preferably, the second regeneration temperature is 380-450°C, preferably 380-430°C; the second constant temperature holding time is 5-24h, preferably 8-15h.

[0034] In the present invention, the second regeneration temperature may be higher than the first regeneration temperature, or may be the same as the first regeneration temperature. Preferably, the second regeneration temperature is the same as the first regeneration temperature.

[0035] When the second regeneration temperature may be higher than the first regeneration temperature, preferably, the heating rate of heating to the second regeneration temperature is 0.1-10° C. / min.

[0036] The present invention adopts the above-mentioned specific second regeneration process to help increase particle strength and improve catalyst activity.

[0037] According to the present invention, preferably, the regeneration method further comprises: cooling the second regeneration product from the second regeneration temperature to room temperature in a third regeneration atmosphere.

[0038] According to the present invention, preferably, the third regeneration atmosphere is selected from air, and an inert gas and / or water vapor.

[0039] According to the present invention, preferably, in the third regeneration atmosphere, the volume content of the air is 10-60%, for example, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% and any value in the range formed by any two of these point values; the volume content of the inert gas is 0-80%, for example, it can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 65%, 70%, 75%, 80% and any value in the range formed by any two of these point values; the volume content of water vapor is 0-40%, for example, it can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40% and any value in the range formed by any two of these point values.

[0040] According to the present invention, preferably, the volume space velocity of the third regeneration atmosphere is 300-2000h -1 , preferably 800-1500h -1 .

[0041] According to the present invention, preferably, the cooling rate to room temperature is 1-5°C / min.

[0042] The specific cooling process adopted in the present invention is beneficial to maintaining the activity and particle strength of the catalyst after regeneration.

[0043] According to the present invention, preferably, the deactivated catalyst is a vanadium phosphorus oxygen catalyst. Vanadium phosphorus oxygen catalyst is the most widely used catalyst with the best application effect in the field of n-butane oxidation to maleic anhydride. Therefore, the present invention mainly regenerates such catalyst.

[0044] The present invention has no particular limitation on the specific composition of the deactivated catalyst, which can be a deactivated catalyst after long-term operation of various compositions of vanadium-phosphorus-oxygen catalysts conventionally used in the field of n-butane oxidation to maleic anhydride. Preferably, in the deactivated catalyst, the mass ratio of vanadium to phosphorus, calculated as elements, is 0.5-2:1.

[0045] The regeneration method of the present invention can be used to regenerate the catalyst by an online method without disassembling the catalyst, which is simple to operate, saves time and effort, is easy to operate, does not require large-scale transformation of industrial equipment, and reduces labor costs and safety risks. Preferably, the regeneration process of the deactivated catalyst is carried out in a reactor for producing maleic anhydride by oxidation of n-butane.

[0046] The present invention has no particular limitation on the loading amount of the deactivated catalyst in the n-butane oxidation to maleic anhydride reactor, which is generally the loading amount of the fresh catalyst in the n-butane oxidation to maleic anhydride reaction, that is, the amount loaded for the reaction is the amount regenerated later.

[0047] The particle strength of the regenerated catalyst obtained by the regeneration method of the present invention is significantly improved and can be close to the particle strength of the fresh catalyst (55-80N). According to the present invention, preferably, the particle strength of the regenerated catalyst is 50-70N.

[0048] The present invention will be described in detail below through examples.

[0049] The particle strength of the catalyst of the present invention is measured by using a clover-shaped (manufactured by Huntsman) particle strength tester. Determination method: Measure 10 samples to be tested. Set the relevant measurement parameters of the particle strength tester, place a catalyst particle sample to be tested on the sample table, click the measurement button, and slowly drop the force rod to increase the pressure until the catalyst particles to be measured are broken, and record the pressure data. Take the average of the pressure data of the 10 catalyst particles to be measured, which is the particle strength of the catalyst;

[0050] The deactivated catalyst used in the following examples was heated at 420°C and fed with n-butane and air, with a n-butane volume fraction of 1.8% and a volume space velocity of 2000 h / min. -1 After a period of reaction under the same conditions, the mass yield of maleic anhydride was 77.6wt%, and the particle strength of the deactivated catalyst was 35.06N.

[0051] Example 1

[0052] The deactivated catalyst (mass ratio of V to P was 1.6:1) was placed in a fixed bed reactor with a filling volume of 30 mL.

[0053] Step 1 - First regeneration: At room temperature, nitrogen was introduced with a total volume space velocity of 1000 h -1 The temperature was raised at a rate of 1°C / min to 380°C for the catalyst bed and maintained at this temperature for 1 h.

[0054] Step 2 - Second regeneration: The catalyst bed was maintained at 380°C and isobutanol, nitrogen, air and water vapor were introduced at corresponding volume fractions of 1%, 50%, 24% and 25% respectively, with a total volume space velocity of 1000 h -1 , and keep at this temperature for 15h.

[0055] Step 3 - Cooling: nitrogen and air are introduced, with the volume fractions of nitrogen and air being 60% and 40% respectively, and the total volume air velocity being 1000h -1 The catalyst after the second regeneration was cooled to room temperature at a rate of 1°C / min. The particle strength parameters of the regenerated catalyst are shown in Table 1.

[0056] The regenerated catalyst was subjected to performance evaluation. The temperature of the catalyst bed was directly raised to 420°C, and n-butane and air were introduced. The volume fraction of n-butane was 1.8%, and the volume space velocity of n-butane and air was 2000 h-1. -1 The catalytic evaluation results after 24 h of reaction are shown in Table 2.

[0057] Wherein, the volume fraction of n-butane=the volume of n-butane introduced / (the volume of n-butane introduced+the volume of air introduced)×100%.

[0058] Example 2

[0059] The deactivated catalyst (mass ratio of V to P was 1.6:1) was placed in a fixed bed reactor with a filling volume of 30 mL.

[0060] Step 1 - First regeneration: At room temperature, nitrogen was introduced with a volumetric space velocity of 1500 h -1The temperature of the catalyst bed was raised to 450°C at a heating rate of 5°C / min and maintained at this temperature for 1 h.

[0061] Step 2 - Second regeneration: The catalyst bed is maintained at 450°C and is introduced with isopropanol, nitrogen, air and water vapor at volume fractions of 1%, 80%, 9% and 10% respectively, with a total volume space velocity of 2000 h -1 , and keep at this temperature for 10h.

[0062] Step 3 - Cooling: Air and nitrogen are introduced, with the volume fractions of nitrogen and air being 80% and 20% respectively, and the total volume air velocity being 1000h -1 The catalyst after the second regeneration was cooled to room temperature at a rate of 5°C / min. The strength parameters of the catalyst after regeneration are shown in Table 1.

[0063] The regenerated catalyst was subjected to performance evaluation. The temperature of the catalyst bed was directly raised to 420°C, and n-butane and air were introduced. The volume fraction of n-butane was 1.8%, and the volume space velocity of n-butane and air was 2000 h-1. -1 The catalytic evaluation results after 24 h of reaction are shown in Table 2.

[0064] Example 3

[0065] The deactivated catalyst (mass ratio of V to P was 1.6:1) was placed in a fixed bed reactor with a filling volume of 30 mL.

[0066] Step 1 - First regeneration: At room temperature, nitrogen was introduced with a total volume space velocity of 1000 h -1 The temperature was raised at a rate of 0.5°C / min to 410°C for the catalyst bed and maintained at this temperature for 5 h.

[0067] Step 2 - Second regeneration: The catalyst bed was maintained at 410°C and regenerated by introducing isopropanol, nitrogen, air and water vapor. The corresponding volume fractions were 0.2%, 50%, 24.8% and 25%, respectively. The total volume space velocity was 1000h -1 , and keep at this temperature for 10h.

[0068] Step 3 - Cooling: nitrogen and air are introduced, with the volume fractions of nitrogen and air being 50% and 50% respectively, and the total volume air velocity being 1000h -1 The catalyst after the second regeneration was cooled to room temperature at a rate of 1°C / min. The strength parameters of the catalyst after regeneration are shown in Table 1.

[0069] The regenerated catalyst was subjected to performance evaluation. The temperature of the catalyst bed was directly raised to 420°C, and n-butane and air were introduced. The volume fraction of n-butane was 1.8%, and the volume space velocity of n-butane and air was 2000 h-1.-1 The catalytic evaluation results after 24 h of reaction are shown in Table 2.

[0070] Example 4

[0071] The deactivated catalyst (mass ratio of V to P was 1.6:1) was placed in a fixed bed reactor with a filling volume of 30 mL.

[0072] Step 1 - First regeneration: At room temperature, nitrogen was introduced with a volumetric space velocity of 1300 h -1 The temperature of the catalyst bed was raised to 380°C at a heating rate of 1°C / min and maintained at this temperature for 5 h.

[0073] Step 2 - Second regeneration: The catalyst bed was maintained at 380°C and isobutanol, nitrogen, air and water vapor were introduced at corresponding volume fractions of 1%, 50%, 20% and 29% respectively, with a total volume space velocity of 1300 h -1 , and keep at this temperature for 10h.

[0074] Step 3 - Cooling: nitrogen and air are introduced, with the volume fractions of nitrogen and air being 50% and 50% respectively, and the total volume air velocity being 1300h -1 The catalyst after the second regeneration was cooled to room temperature at a rate of 2°C / min. The strength parameters of the catalyst after regeneration are shown in Table 1.

[0075] The regenerated catalyst was subjected to performance evaluation. The temperature of the catalyst bed was directly raised to 420°C, and n-butane and air were introduced. The volume fraction of n-butane was 1.8%, and the volume space velocity of n-butane and air was 2000 h-1. -1 The catalytic evaluation results after 24 h of reaction are shown in Table 2.

[0076] Example 5

[0077] The deactivated catalyst (mass ratio of V to P was 1.6:1) was placed in a fixed bed reactor with a filling volume of 30 mL.

[0078] Step 1 - First regeneration: At room temperature, nitrogen was introduced with a volumetric space velocity of 800 h -1 The temperature was raised at a rate of 0.1°C / min to 410°C for 0 h.

[0079] Step 2 - Second regeneration: The catalyst bed was maintained at 410°C and ethanol, isopropanol, nitrogen, air and water vapor were introduced at corresponding volume fractions of 1%, 1%, 50%, 25% and 23% respectively, with a total volume space velocity of 800 h -1 , and keep at this temperature for 10h.

[0080] Step 3 - Cooling: nitrogen, air and water vapor are introduced, with the volume fractions of nitrogen, air and water vapor being 50%, 45% and 5% respectively, and the total volume air velocity being 800h -1 The catalyst after the second regeneration was cooled to room temperature at a rate of 2°C / min. The strength parameters of the catalyst after regeneration are shown in Table 1.

[0081] The regenerated catalyst was subjected to performance evaluation. The temperature of the catalyst bed was directly raised to 420°C, and n-butane and air were introduced. The volume fraction of n-butane was 1.8%, and the volume space velocity of n-butane and air was 2000 h-1. -1 The catalytic evaluation results after 24 h of reaction are shown in Table 2.

[0082] Example 6

[0083] The method of Example 1 was followed, except that the regeneration temperature of the first regeneration process and the second regeneration process were both 445°C.

[0084] The catalyst strength parameters after regeneration are shown in Table 1.

[0085] The regenerated catalyst was subjected to performance evaluation. The temperature of the catalyst bed was directly raised to 420°C, and n-butane and air were introduced. The volume fraction of n-butane was 1.8%, and the volume space velocity of n-butane and air was 2000 h-1. -1 The catalytic evaluation results after 24 h of reaction are shown in Table 2.

[0086] Example 7

[0087] The method of Example 1 is followed, except that the second regeneration atmosphere of the second regeneration process is isobutanol, ethanol, nitrogen, air and water vapor, and the corresponding volume fractions are 1%, 0.5%, 50%, 25% and 23.5%, respectively.

[0088] The catalyst strength parameters after regeneration are shown in Table 1.

[0089] The regenerated catalyst was subjected to performance evaluation. The temperature of the catalyst bed was directly raised to 420°C, and n-butane and air were introduced. The volume fraction of n-butane was 1.8%, and the volume space velocity of n-butane and air was 2000 h-1. -1 The catalytic evaluation results after 24 h of reaction are shown in Table 2.

[0090] Comparative Example 1

[0091] The method of Example 1 is followed, except that the second regeneration atmosphere of the second regeneration process is nitrogen, air and water vapor, and the corresponding volume fractions are 50%, 25% and 25%, respectively.

[0092] The catalyst strength parameters after regeneration are shown in Table 1.

[0093] The regenerated catalyst was subjected to performance evaluation. The temperature of the catalyst bed was directly raised to 420°C, and n-butane and air were introduced. The volume fraction of n-butane was 1.8%, and the volume space velocity of n-butane and air was 2000 h-1. -1 The catalytic evaluation results after 24 h of reaction are shown in Table 2.

[0094] Table 1

[0095]

[0096]

[0097] It can be seen from the results in Table 1 that the regenerated catalyst obtained by the regeneration method of the present invention has higher strength, enhanced wear resistance, and further extended catalyst life. In addition, the catalyst strength is enhanced, which reduces the degree of catalyst pulverization under long-term operation, thereby reducing costs and increasing efficiency for the stable operation of the device.

[0098] Table 2

[0099] Example No. n-Butane conversion rate / % Maleic anhydride mass yield / wt% Fresh Catalyst 90.09 110.77 Deactivated catalyst 58.21 77.6 Example 1 86.50 104.65 Example 2 82.23 99.87 Example 3 83.17 101.09 Example 4 87.00 105.37 Example 5 87.23 105.68 Example 6 84.2 100.99 Example 7 87.5 107.46 Comparative Example 1 87.65 103.50

[0100] Note: The evaluation results of fresh catalyst were obtained under the same conditions as in the example.

[0101] It can be seen from the results in Table 2 that the regenerated catalyst obtained by the regeneration method of the present invention still has a high n-butane conversion rate and a high maleic anhydride yield when applied to the n-butane oxidation to maleic anhydride reaction. This shows that the catalyst obtained by the regeneration method of the present invention has a significantly higher activity.

[0102] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for regenerating a deactivated catalyst for producing maleic anhydride by oxidation of n-butane, the method comprising: The following steps are involved: The deactivated catalyst for preparing maleic anhydride by oxidation of n-butane is subjected to a first regeneration and a second regeneration; Wherein, the first regeneration atmosphere is an inert gas; Wherein, the second regeneration atmosphere is alcohol vapor, and at least one of water vapor, inert gas and air.

2. The method according to claim 1, in, The volume space velocity of the first regeneration atmosphere is 300-2000h -1 , preferably 800-1500h -1 .

3. The method according to claim 1, in, In the second regeneration atmosphere, the volume content of alcohol vapor is 0.1-5%; the volume content of water vapor is 0-50%; the volume content of the inert gas is 0-80%; and the volume content of air is 0-45%.

4. The method according to any one of claims 1 to 3, in, The second regeneration atmosphere is alcohol vapor, water vapor, inert gas and air; Preferably, in the second regeneration atmosphere, the volume content of alcohol vapor is 1-3.5%; the volume content of water vapor is 10-35%; the volume content of the inert gas is 40-80%; the volume content of the air is 8-30%; Preferably, the volume space velocity of the second regeneration atmosphere is 300-2000h -1 , preferably 800-1500h -1 .

5. The method according to any one of claims 1 to 4, in, The alcohol vapor is selected from C 1 -C 4 The alcohol is preferably selected from at least one of ethanol, isopropanol and isobutanol; Further preferably, the alcohol vapor is isobutanol, ethanol and / or isopropanol; Preferably, the volume ratio of isobutanol to ethanol and / or isopropanol is 1:0.3-1.

6. The method according to any one of claims 1 to 5, in, The first regeneration comprises: heating the deactivated catalyst from room temperature to a first regeneration temperature in a first regeneration atmosphere, and then maintaining the temperature at a first constant temperature; Preferably, the first regeneration temperature is 380-450°C, preferably 380-430°C; the first constant temperature holding time is 0-8h, preferably 0-5h; Preferably, the heating rate of heating to the first regeneration temperature is 0.1-10°C / min, preferably 0.1-7°C / min.

7. The method according to any one of claims 1 to 6, in, The second regeneration conditions include: maintaining the first regeneration product at a second constant temperature at a second regeneration temperature in a second regeneration atmosphere; Preferably, the second regeneration temperature is 380-450°C, preferably 380-430°C; the second constant temperature holding time is 5-24h, preferably 8-15h.

8. The method according to claim 7, in, The regeneration method further comprises: cooling the second regeneration product from a second regeneration temperature to room temperature in a third regeneration atmosphere; Preferably, the third regeneration atmosphere is selected from air, and an inert gas and / or water vapor; Preferably, in the third regeneration atmosphere, the volume content of the air is 10-60%, the volume content of the inert gas is 0-80%, and the volume content of the water vapor is 0-40%; Preferably, the volume space velocity of the third regeneration atmosphere is 300-2000h -1 , preferably 800-1500h -1 ; Preferably, the cooling rate to room temperature is 1-5°C / min.

9. The method according to any one of claims 1 to 8, in, The deactivated catalyst is a vanadium phosphorus oxygen catalyst; Preferably, in the deactivated catalyst, the mass ratio of vanadium to phosphorus, calculated as elements, is 0.5-2:

1.

10. The method according to any one of claims 1 to 9, in, The regeneration process of the deactivated catalyst is carried out in a reactor for producing maleic anhydride by oxidation of n-butane.

11. The method according to any one of claims 1 to 10, in, The particle strength of the regenerated catalyst is 50-70N.

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