In-situ regeneration method of ruthenium-based catalyst

Abstract

The invention discloses an in-situ regeneration method of a ruthenium-based catalyst. The regeneration method comprises the following steps: carrying out primary reduction treatment on an inactivated ruthenium-based catalyst in hydrogen or diluent gas formed by mixing hydrogen and nitrogen, then carrying out oxidation treatment in an oxygen-containing atmosphere, and then carrying out secondary reduction treatment in a reducing atmosphere. According to the regeneration method provided by the invention, the activity recovery rate of the inactivated ruthenium-based catalyst can reach 100%, the service life of the ruthenium-based catalyst is prolonged, the utilization efficiency of the ruthenium-based catalyst is improved, and the regeneration method is simple to operate, easy to implement and relatively high in economical efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst regeneration, and in particular to an in-situ regeneration method of a ruthenium-based catalyst. Background Art

[0002] In the research and development of industrial catalysts, the regeneration of deactivated catalysts is a crucial topic and a daunting challenge. This issue involves multiple factors, such as economics and resource conservation, industrial production efficiency, and environmental and energy sustainability.

[0003] Catalysts play a key role in industrial production, accelerating chemical reactions and improving product selectivity, both economically and in terms of resource conservation. However, with increasing resource scarcity and intensifying environmental concerns, efficiently utilizing catalysts and minimizing their environmental impact has become a pressing issue. Catalyst recycling and regeneration technologies are crucial for resource conservation and environmental protection. Regeneration technologies can significantly extend catalyst life, reduce production costs, and minimize resource waste and environmental pollution caused by discarded catalysts.

[0004] Catalyst deactivation is a common problem in industrial catalytic processes, often leading to decreased production efficiency and increased costs. The causes of catalyst deactivation vary, primarily including carbon deposition, poisoning, and sintering. These factors can cover active sites or block pores, reducing catalyst activity. Therefore, developing effective catalyst regeneration methods to restore catalyst activity is crucial for ensuring the continuity and economic viability of industrial production.

[0005] In the face of increasingly severe environmental and energy challenges, catalyst regeneration technology has emerged. Catalyst regeneration technology involves restoring the catalytic efficiency of a degraded catalyst through specific chemical or physical methods. This technology is crucial for reducing environmental pollution and improving energy efficiency.

[0006] Although a variety of chemical reactions and methods exist to remove the factors that cause catalyst deactivation, developing reliable, efficient, and economical catalyst regeneration methods remains an urgent challenge in industrial practice. Current research progress includes regeneration methods such as oxidation (such as air, ozone, and nitrogen oxides), gasification (such as carbon dioxide and water vapor), and hydrogenation (such as hydrogen). For example, the regeneration technology of vanadium-based catalysts and Co-based catalysts is relatively mature, using physical and chemical methods to remove carbon deposits on the catalyst surface and restore its activity.

[0007] In recent years, research on direct synthesis of olefins from syngas has made significant progress. This technology is gradually moving from the laboratory to industrialization, providing a new development direction for the energy and chemical industry. Among them, the Ru-based catalyst developed by the Shanghai Advanced Research Institute of the Chinese Academy of Sciences has unique advantages in this field: it can produce olefins with high selectivity while controlling the overall selectivity of the byproducts CH4 and CO2 to less than 5%. Pilot-scale trials have been successfully completed, demonstrating promising prospects for industrial application. However, due to the high production cost of Ru, deactivated Ru-based catalysts must be regenerated.

[0008] CN111686824A discloses a method for soaking and washing a deactivated ruthenium-based catalyst with naphtha, purging the soaked and washed catalyst with an inert gas, oxidizing it with an oxygen-containing gas, and then reducing it with hydrogen to obtain a regenerated catalyst. This patent requires removing the deactivated ruthenium-based catalyst from a fixed bed and then soaking it, which prevents in-situ regeneration and is time-consuming and labor-intensive.

[0009] Therefore, the development of an efficient and economical catalyst regeneration method that can achieve in situ regeneration is of great significance for improving industrial production efficiency, reducing production costs, protecting environmental resources, and promoting sustainable development in the energy and chemical industry. Summary of the Invention

[0010] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide an in-situ regeneration method for a ruthenium-based catalyst.

[0011] To achieve the above-mentioned purpose and other related purposes, the present invention is achieved through the following technical solutions.

[0012] A first aspect of the present invention provides a method for in-situ regeneration of a ruthenium-based catalyst, comprising the following steps:

[0013] The deactivated ruthenium-based catalyst is subjected to a first reduction treatment in a diluent gas formed by hydrogen or a mixture of hydrogen and nitrogen, followed by an oxidation treatment in an oxidizing atmosphere, and then a second reduction treatment in a reducing atmosphere.

[0014] In industrial applications, ruthenium-based catalysts are widely used due to their efficient catalytic performance. However, under high temperature conditions, the surface atoms of the metal ruthenium particles in the ruthenium-based catalysts have high thermal energy and are prone to migration and diffusion. This migration and diffusion will lead to enhanced interactions between the particles, thereby promoting particle growth. The active component ruthenium may grow due to particle growth (exceeding 8nm). In addition, ruthenium-based catalysts sinter or chemically change under high temperature or reaction conditions, thereby affecting the dispersibility and stability of the metal ruthenium particles, causing the metal ruthenium particles to agglomerate and reducing the specific surface area of ​​the catalyst. These factors combined lead to the deactivation of the ruthenium-based catalyst. In response to the problems of ruthenium particles growing, being covered by impurities and agglomerating during the use of ruthenium-based catalysts, the present invention proposes an innovative in-situ regeneration method. The method reduces the ruthenium oxide on the surface of the deactivated catalyst to metallic ruthenium through a first reduction treatment, which restores its active state; then an oxidation treatment is performed to remove carbon deposits and other organic impurities on the surface of the catalyst, and an oxide layer is formed on the surface of the generated metallic ruthenium. This treatment not only removes surface impurities but also prepares for subsequent reduction treatment; then a second reduction treatment is performed to remove the oxide layer on the surface of the metallic ruthenium, making the metallic ruthenium highly dispersed to form particles of appropriate size (4-6nm). This treatment not only restores the activity of the catalyst but also significantly improves its dispersibility and stability. The present invention successfully achieves the regeneration of the deactivated catalyst, so that the activity recovery rate of the catalyst can reach 100%. The surface load of the regenerated ruthenium-based catalyst is evenly dispersed, the metallic ruthenium particles are 4-6 nanometers in size, and no agglomeration occurs. The present invention not only restores the activity of the catalyst but also improves its performance, making it more competitive in industrial applications.

[0015] In some embodiments, the temperature of the first reduction treatment can be 100-500°C, or 100-250°C, or 200-350°C, or 300-500°C, or 100, 200, 300, 400, or 500°C. The present invention can effectively remove heavy or long-chain olefin products or alkanes adsorbed on the surface of the deactivated ruthenium-based catalyst through high-temperature reduction, thereby removing impurities. The temperature of the reduction treatment should not be too high or too low. If it is too high, the particle size of the metal ruthenium particles will be too large. If it is too low, the reduction will be incomplete, and oxidized ruthenium will be present.

[0016] In some embodiments, the pressure of the first reduction treatment can be 1-20 bar, 1-12 bar, 9-17 bar, 15-20 bar, or 1, 3, 7, 9, 11, 13, 14, 15, 17, or 20 bar.

[0017] In some embodiments, the first reduction treatment time can be 2 to 15 hours, 2 to 8 hours, 6 to 11 hours, 9 to 15 hours, or 2, 5, 8, 10, 11, 12, 13, 14, or 15 hours.

[0018] In some embodiments, during the first reduction treatment, the space velocity of hydrogen or diluent gas may be 3000 to 12000 mL g -1 h -1 , or 3000~6000mL g -1 h -1 , or 5000~9000mL g -1 h -1 , or 8000~12000mL g -1 h -1 , can also be 3000, 5000, 8000, 10000, 11000, 12000mL g -1 h -1 .

[0019] In some embodiments, in the dilution gas, the volume ratio of hydrogen and nitrogen can be (5-80):(20-95), (5-80):(20-55), (5-80):(45-75), (5-80):(65-95), or 10:90, 50:50, or 80:20.

[0020] In some embodiments, the deactivated ruthenium-based catalyst undergoes a first reduction treatment in a diluent atmosphere consisting of a mixture of hydrogen and nitrogen. By diluting the hydrogen with nitrogen, the present invention effectively controls the rate of reduction, preventing structural changes in the catalyst caused by aggressive reduction. Furthermore, it reduces the partial pressure of water during the reduction process, preventing further oxidation of the ruthenium metal.

[0021] In some embodiments, the temperature of the oxidation treatment can be 50-400°C, or 100-250°C, or 200-350°C, or 300-500°C, or 100, 150, 200, 300, 400, or 500°C. The present invention forms an oxide layer on the surface of the metallic ruthenium obtained by the first reduction through the oxidation treatment, thereby preventing the agglomeration of the metallic ruthenium. The temperature of the oxidation treatment should be neither too high nor too low. Too high results in excessive oxidation, causing the entire catalyst to completely convert into ruthenium oxide, while too low results in no oxidation.

[0022] In some embodiments, the oxidation treatment time can be 1 to 20 hours, 1 to 8 hours, 6 to 14 hours, 13 to 20 hours, or 1, 5, 8, 10, 11, 12, 13, 14, 15, or 20 hours.

[0023] In some embodiments, the oxidizing atmosphere is selected from one or more of oxygen, hydrogen peroxide vapor, and a diluent gas formed by a mixture of oxygen and nitrogen.

[0024] In some specific embodiments, the oxidizing atmosphere is a diluent gas formed by a mixture of oxygen and nitrogen.

[0025] In some more specific embodiments, in the diluent gas, the volume ratio of oxygen and nitrogen is (5-90):(10-95), or (5-90):(10-45), or (5-90):(40-65), or (5-90):(60-95), or 10:90, 50:50, or 60:40.

[0026] In some specific embodiments, the concentration of the hydrogen peroxide vapor can be 20-40 wt %, 20-35 wt %, 30-40 wt %, or 20, 25, 30, 35, or 40 wt %. Concentrations higher than this may result in excessive oxidation, converting the entire catalyst completely into ruthenium oxide, while concentrations lower than this may result in no oxidation.

[0027] In some embodiments, the temperature of the second reduction treatment can be 100-300° C., 100-220° C., 160-280° C., 210-300° C., or 100, 150, 200, or 300° C. The present invention removes the ruthenium oxide layer through low-temperature reduction and achieves a better dispersion effect.

[0028] In some embodiments, the pressure of the second reduction treatment may be 1 to 5 bar, 1 to 3 bar, 2 to 5 bar, or 1, 2, 3, 4, or 5 bar.

[0029] In some embodiments, the second reduction treatment may last for 2 to 10 hours, 2 to 7 hours, 6 to 10 hours, or 2, 4, 5, 8, or 10 hours.

[0030] In some embodiments, the space velocity of the reducing atmosphere during the second reduction treatment may be 3000 to 12000 mL g - 1 h -1 , or 3000~6000mL g -1 h-1 , or 5000~9000mL g -1 h -1 , or 8000~12000mL g -1 h -1 , can also be 3000, 5000, 8000, 10000, 11000, 12000mL g -1 h -1 .

[0031] In some embodiments, the reducing atmosphere is selected from one or both of hydrogen and synthesis gas, and a diluent gas formed by mixing one or both of hydrogen and synthesis gas with nitrogen.

[0032] In some specific embodiments, the synthesis gas is hydrogen and carbon monoxide, and the volume ratio of the hydrogen to carbon monoxide is (1-3):1.

[0033] In some specific embodiments, the reducing atmosphere is a diluent gas formed by mixing synthesis gas and nitrogen, wherein the volume ratio of synthesis gas to nitrogen is 50:50 to 10:90, preferably 10:90.

[0034] In some embodiments, the ruthenium-based catalyst is a supported metal ruthenium catalyst, which comprises at least a ruthenium metal oxide and a support.

[0035] In some specific embodiments, the mass of ruthenium in the ruthenium metal oxide is 0.1 wt% to 15 wt% based on the mass of the support; the ruthenium-based catalyst further comprises a copper metal oxide; the mass of copper in the copper metal oxide does not exceed 30 wt% based on the mass of the support. The ruthenium-based catalyst is obtained by conventional methods, including but not limited to CN117358230A.

[0036] In some more specific embodiments, the metal promoter includes one or more of calcium, magnesium, lithium, sodium, potassium, rubidium, cesium, cerium, barium, and manganese.

[0037] In some more specific embodiments, the structural additive is one or more of silicon oxide, aluminum oxide, zirconium oxide, and titanium oxide.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1) The present invention provides an in-situ regeneration method for a ruthenium-based catalyst. Through a three-step treatment process of reduction-oxidation-reduction, the regeneration of the deactivated catalyst is achieved. The surface of the regenerated ruthenium-based catalyst is loaded with uniformly dispersed metallic ruthenium with a size of 4-6 nm and will not agglomerate, effectively solving the problem of poor activity recovery of the deactivated ruthenium-based catalyst after regeneration.

[0040] 2) This invention provides an in-situ regeneration method for a ruthenium-based catalyst. Without changing other reaction conditions, the CO conversion rate can be restored to 100%. Compared to a deactivated catalyst, the regenerated catalyst achieves a CO conversion rate improvement of at least 25.7%. This significant performance improvement not only extends the catalyst's lifespan but also reduces production costs, improving the economics and efficiency of industrial production.

[0041] 3) This invention provides an in-situ regeneration method for ruthenium-based catalysts. This method can be performed on the fixed bed where the catalytic reaction originally took place, eliminating the need to remove the catalyst, making it convenient and quick. Furthermore, through a reduction-oxidation-reduction process, the problem of catalyst deactivation is successfully resolved, significantly improving catalyst performance and service life. This technology has significant application value and broad market prospects in the field of industrial catalyst regeneration. DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0043] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are for describing specific specific embodiments rather than for limiting the scope of protection of the present invention; in the present specification and claims, unless otherwise expressly stated herein, the singular forms "a", "an" and "the" include plural forms.

[0044] When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the understanding of the prior art by those skilled in the art and the description of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention may also be used to implement the present invention.

[0045] The deactivated ruthenium-based catalyst in the following examples of this application is continuously operated for 10,000 hours in the Fischer-Tropsch synthesis reaction. -1 The ruthenium-based catalyst was tested and compared with the initial reaction time, it was continuously operated for 10,000 hours.-1 The CO conversion rate dropped by 30% after adding a ruthenium-based catalyst. The ruthenium-based catalyst is composed of ruthenium, sodium, and a structural promoter (silicon oxide). Calculated by weight, the ruthenium-based catalyst includes 3 wt% ruthenium, 0.5 wt% sodium, and 96.5 wt% of the structural promoter (silicon oxide). The ruthenium content is calculated as the weight of metallic ruthenium, and the structural promoter content is calculated as the weight of the corresponding oxide.

[0046] The following in-situ regeneration method is carried out in a fixed bed, including but not limited to a shell-and-tube fixed bed reactor.

[0047] Example 1

[0048] In this embodiment 1, a method for in-situ regeneration of a ruthenium-based catalyst is provided, comprising the following steps:

[0049] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in hydrogen. The first reduction treatment was carried out for 5 h at a temperature of 200 °C, a pressure of 1 bar, and a space velocity of 8000 mL g -1 h -1 .

[0050] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, followed by oxidation in an oxidizing atmosphere of oxygen for 5 hours at 100°C and atmospheric pressure (1.01325 bar).

[0051] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is hydrogen; the second reduction treatment is carried out for 5 hours at a temperature of 200°C, a pressure of 1 bar, and a space velocity of 8000 mL g -1 h -1 .

[0052] Example 2

[0053] In this embodiment 2, a method for in-situ regeneration of a ruthenium-based catalyst is provided, comprising the following steps:

[0054] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in hydrogen. The first reduction treatment was carried out for 5 h at a temperature of 200 °C, a pressure of 1 bar, and a space velocity of 12000 mL g -1 h -1 .

[0055] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, followed by oxidation in an oxidizing atmosphere. The oxidizing atmosphere was a diluent mixture of hydrogen and nitrogen, with an oxygen concentration of 10 v / v% (O2:N2 volume ratio of 10:90). The oxidation treatment lasted 5 hours at 100°C and atmospheric pressure (1.01325 bar).

[0056] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is hydrogen; the second reduction treatment is carried out for 5 hours at a temperature of 300°C, a pressure of 5 bar, and a space velocity of 12000 mL g -1 h -1 .

[0057] Example 3

[0058] In this embodiment 3, a method for in-situ regeneration of a ruthenium-based catalyst is provided, comprising the following steps:

[0059] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in a diluent gas consisting of a mixture of hydrogen and nitrogen. The hydrogen concentration in the diluent gas was 10 v / v% (i.e., a volume ratio of H2:N2 of 10:90). The first reduction treatment lasted 10 h at a temperature of 400°C, a pressure of 5 bar, and a space velocity of 12,000 mL g -1 h -1 .

[0060] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, followed by oxidation in an oxidizing atmosphere comprising a diluent mixture of oxygen and nitrogen (O2:N2 volume ratio of 10:90). The oxidation treatment lasted 5 hours at 100°C and atmospheric pressure (1.01325 bar).

[0061] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is hydrogen; the second reduction treatment is carried out for 5 hours at a temperature of 300°C, a pressure of 5 bar, and a space velocity of 12000 mL g -1 h -1 .

[0062] Example 4

[0063] This embodiment 4 provides an in-situ regeneration method for a ruthenium-based catalyst, comprising the following steps:

[0064] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in hydrogen. The first reduction treatment was carried out for 2 h at a temperature of 100 °C, a pressure of 2 bar, and a space velocity of 12000 mL g -1 h -1 .

[0065] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, followed by oxidation in an oxidizing atmosphere. The oxidizing atmosphere was provided by 3 wt% hydrogen peroxide vapor. The oxidation treatment lasted for 10 hours at a temperature of 150°C and atmospheric pressure (1.01325 bar).

[0066] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is hydrogen; the second reduction treatment is carried out for 5 hours at a temperature of 300°C, a pressure of 5 bar, and a space velocity of 12000 mL g -1 h -1 .

[0067] Example 5

[0068] In this embodiment 5, a method for in-situ regeneration of a ruthenium-based catalyst is provided, comprising the following steps:

[0069] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in hydrogen. The first reduction treatment was carried out for 5 h at a temperature of 200 °C, a pressure of 1 bar, and a space velocity of 12000 mL g -1 h -1 .

[0070] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, followed by oxidation in an oxidizing atmosphere comprising a diluent mixture of hydrogen and nitrogen (O2:N2 in a 50:50 volume ratio). The oxidation treatment lasted for 1 hour at 300°C and atmospheric pressure (1.01325 bar).

[0071] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is hydrogen; the second reduction treatment is carried out for 5 hours at a temperature of 300°C, a pressure of 5 bar, and a space velocity of 12000 mL g -1 h -1 .

[0072] Example 6

[0073] In this embodiment 6, a method for in-situ regeneration of a ruthenium-based catalyst is provided, comprising the following steps:

[0074] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in a dilution gas consisting of a mixture of hydrogen and nitrogen. The hydrogen concentration in the dilution gas was 50 v / v% (H2:N2 volume ratio was 50:50). The first reduction treatment lasted 5 hours at a temperature of 200°C, a pressure of 1 bar, and a space velocity of 12,000 mL g -1 h -1 .

[0075] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, followed by oxidation in an oxidizing atmosphere. The oxidizing atmosphere was a diluent mixture of hydrogen and nitrogen, with an oxygen concentration of 60 v / v% (O2:N2 volume ratio of 60:40). The oxidation treatment lasted for 1 hour at 300°C and atmospheric pressure (1.01325 bar).

[0076] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is hydrogen; the second reduction treatment is carried out for 5 hours at a temperature of 300°C, a pressure of 2 bar, and a space velocity of 12000 mL g -1 h -1 .

[0077] Example 7

[0078] In this embodiment 7, a method for in-situ regeneration of a ruthenium-based catalyst is provided, comprising the following steps:

[0079] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in a dilution gas consisting of a mixture of hydrogen and nitrogen. The hydrogen concentration in the dilution gas was 80 v / v% (H2:N2 volume ratio was 80:20). The first reduction treatment lasted 3 h at a temperature of 250°C, a pressure of 3 bar, and a space velocity of 3000 mL g -1 h -1 .

[0080] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, followed by oxidation in an oxidizing atmosphere. The oxidizing atmosphere was provided by 30% hydrogen peroxide vapor. The oxidation treatment lasted for 2 hours at 150°C and atmospheric pressure (1.01325 bar).

[0081] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is hydrogen; the second reduction treatment is carried out for 5 hours at a temperature of 300°C, a pressure of 2 bar, and a space velocity of 3000 mL g -1 h -1 .

[0082] Example 8

[0083] In this embodiment 8, a method for in-situ regeneration of a ruthenium-based catalyst is provided, comprising the following steps:

[0084] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in a dilution gas consisting of a mixture of hydrogen and nitrogen. The hydrogen concentration in the dilution gas was 80 v / v% (H2:N2 volume ratio was 80:20). The first reduction treatment lasted 3 h at a temperature of 300°C, a pressure of 1 bar, and a space velocity of 6000 mL g -1 h -1 .

[0085] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, followed by oxidation in an oxidizing atmosphere. The oxidizing atmosphere was provided by 30% hydrogen peroxide vapor. The oxidation treatment was performed at a temperature of 150°C, for 2 hours, at atmospheric pressure (1.01325 bar).

[0086] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is hydrogen; the second reduction treatment is performed for 2 hours at a temperature of 200°C, a pressure of 1 bar, and a space velocity of 12000 mL g -1 h -1 .

[0087] Example 9

[0088] This embodiment 9 provides an in-situ regeneration method for a ruthenium-based catalyst, comprising the following steps:

[0089] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in hydrogen. The first reduction treatment was performed for 2 h at a temperature of 300 °C, a pressure of 1 bar, and a space velocity of 8000 mL g -1 h -1 .

[0090] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, and then oxidized in an oxidizing atmosphere of oxygen for 2 hours at a temperature of 150°C.

[0091] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is hydrogen; the second reduction treatment is performed for 2 hours at a temperature of 200°C, a pressure of 1 bar, and a space velocity of 12000 mL g -1 h -1 .

[0092] Example 10

[0093] In this embodiment 10, a method for in-situ regeneration of a ruthenium-based catalyst is provided, comprising the following steps:

[0094] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in hydrogen. The first reduction treatment was carried out for 2 h at a temperature of 300 °C, a pressure of 1 bar, and a space velocity of 8000 mL g -1 h -1 .

[0095] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, and then oxidized in an oxidizing atmosphere of oxygen for 1 hour at a temperature of 300°C.

[0096] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is hydrogen; the second reduction treatment is performed for 2 h at a temperature of 200°C, a pressure of 1 bar, and a space velocity of 10,000 mL g -1 h -1 .

[0097] Example 11

[0098] This embodiment 11 provides an in-situ regeneration method for a ruthenium-based catalyst, comprising the following steps:

[0099] 1) The deactivated ruthenium-based catalyst was subjected to a first reduction treatment in hydrogen. The first reduction treatment was carried out for 2 h at a temperature of 300 °C, a pressure of 1 bar, and a space velocity of 8000 mL g -1 h -1 .

[0100] 2) The catalyst treated in step 1) was first purged with N2 and cooled to room temperature for 30 minutes, followed by oxidation in an oxidizing atmosphere of oxygen for 1 hour at 300°C and atmospheric pressure (1.01325 bar).

[0101] 3) The catalyst treated in step 2) is then subjected to a second reduction treatment in a reducing atmosphere to obtain a regenerated catalyst. The reducing atmosphere is a diluent gas composed of synthesis gas and nitrogen (synthesis gas / nitrogen = 10 / 90, with a ratio of H2 to CO of 1:3). The second reduction treatment is performed for 2 h at a temperature of 200° C., a pressure of 1 bar, and a space velocity of 10,000 mL g -1 h -1 .

[0102] Example 12

[0103] Compared with Example 4, this Example 12 is different in that the oxidation treatment is carried out in oxygen, and the rest is the same as Example 4.

[0104] Example 13

[0105] Compared with Example 4, this Example 13 is different in that the oxidation treatment is carried out in a dilution gas formed by a mixture of oxygen and nitrogen (the volume ratio of O2:N2 is 50:50), and the rest is the same as Example 4.

[0106] Comparative Example 1

[0107] In Comparative Example 1, the deactivated ruthenium-based catalyst was soaked in the naphtha of CN111686824A, then oxidized in an oxidizing atmosphere, and then reduced in a second reducing atmosphere. The oxidation and reduction treatments were the same as in Example 4.

[0108] Comparative Example 2

[0109] In this comparative example 2, diluted synthesis gas was used for the first reduction treatment, and the rest was the same as in Example 4. The diluted synthesis gas was obtained by mixing synthesis gas and nitrogen in a volume ratio of 10:90, wherein the ratio of H2 to CO was 1:3.

[0110] As can be seen from Table 1, the regeneration effect of the deactivated catalyst by using diluted synthesis gas is not good, which may be due to the easy accumulation of carbon on the surface of ruthenium.

[0111] Comparative Example 3

[0112] The difference between Comparative Example 3 and Example 4 is that the temperature is 90° C.; the rest is the same as Example 4.

[0113] Comparative Example 4

[0114] The difference between Comparative Example 4 and Example 4 is that the temperature is 550° C.; the rest are the same as Example 4.

[0115] Comparative Example 5

[0116] The difference between Comparative Example 5 and Example 4 is that the first reduction treatment is not performed; the rest is the same as Example 4.

[0117] The catalytic performance of the regenerated catalysts obtained in Examples 1-13 and Comparative Examples 1-5 was evaluated, and the results are shown in Table 1.

[0118] The deactivated ruthenium-based catalyst and the catalyst regenerated by the in-situ regeneration method of the present invention are respectively used to catalyze synthesis gas to prepare olefins. During the catalytic reaction, the molar ratio of H2 to CO in the synthesis gas is 1, and the reaction time space velocity is 3000h-1 The reaction temperature was 250°C and the reaction pressure was 10 bar. After the reaction, the types and contents of the various components in the product were analyzed using gas chromatography (Agilent 8860), and the conversion rate and selectivity of the reaction were calculated accordingly. The specific results are shown in Table 1. CO conversion rate = (CO concentration at the end of the reaction - CO concentration at the beginning of the reaction) / CO concentration at the beginning of the reaction.

[0119] Table 1

[0120]

[0121]

[0122] As can be seen from Table 1, the performance advantages of the regenerated catalyst after treatment by the method of the present invention are significant.

[0123] In terms of CO conversion, the method of the present invention improves CO conversion by at least 25.7% compared to the deactivated catalyst. Compared to the naphtha-oxidation-reduction method of Comparative Example 1, the method of the present invention increases the activity recovery rate from 85% to at least 88%, a 3.53% increase. Compared to the first syngas reduction method of Comparative Example 2, the activity recovery rate is also increased from 85% to at least 88%, a 6.02% increase. Compared to Comparative Example 5, which only uses hydrogen peroxide oxidation-reduction treatment, the method of the present invention significantly increases the activity recovery rate from 77% to at least 88%, a 14.3% increase. Furthermore, in comparing the oxidation treatment methods, the method of the present invention, which performs oxidation treatment in diluted oxygen and hydrogen peroxide vapor, achieves superior activity recovery of the regenerated catalyst. The CO conversion rate of the regenerated catalyst after hydrogen peroxide vapor oxidation treatment in Example 4 is 31.4% higher than that of the deactivated catalyst and 2.22% higher than that of the regenerated catalyst after oxidation treatment in oxygen (Example 12).

[0124] In terms of olefin selectivity, the regenerated catalyst treated with the present invention exhibited a reduction in olefin selectivity of less than 5%, demonstrating superior performance. The catalysts obtained by the regeneration methods of Comparative Examples 1, 2, and 5 exhibited reductions in olefin selectivity of 9.894%, 17.46%, and 17.31%, respectively. Furthermore, the regenerated catalyst oxidized in hydrogen peroxide vapor exhibited no decrease in olefin selectivity.

[0125] In summary, the in-situ regeneration method of the present invention achieves an activity recovery rate of up to 100% for the regenerated catalyst. The activity recovery rate refers to the percentage of the catalyst's initial activity after regeneration, measured in terms of CO conversion in this application. This regeneration process can reduce the cost of industrial catalyst applications, extend the service life and utilization efficiency of ruthenium-based catalysts, and is simple to operate, easy to implement, and highly economical.

[0126] The above examples are intended to illustrate the embodiments disclosed herein and are not to be construed as limiting the present invention. In addition, the various modifications listed herein and variations of the methods and compositions in the invention will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. Although the present invention has been specifically described in conjunction with various specific preferred embodiments of the present invention, it should be understood that the present invention should not be limited to these specific embodiments. In fact, various modifications apparent to those skilled in the art as described above to obtain the invention should be included within the scope of the present invention.

Claims

1. A method for in-situ regeneration of a ruthenium-based catalyst, characterized in that: The steps include: The deactivated ruthenium-based catalyst is subjected to a first reduction treatment in a diluent gas formed by hydrogen or a mixture of hydrogen and nitrogen, followed by an oxidation treatment in an oxidizing atmosphere, and then a second reduction treatment in a reducing atmosphere.

2. The in-situ regeneration method according to claim 1, wherein: The temperature of the first reduction treatment is 100-500°C; And / or, the pressure of the first reduction treatment is 1 to 20 bar; And / or, the first reduction treatment lasts for 2 to 15 hours.

3. The in-situ regeneration method according to claim 1, wherein: In the dilution gas, the volume ratio of hydrogen to nitrogen is (5-80):(20-95).

4. The in-situ regeneration method according to claim 1, wherein: The temperature of the oxidation treatment is 50-400°C; And / or, the oxidation treatment time is 1 to 20 hours; And / or, the oxidizing atmosphere is selected from one or more of oxygen, hydrogen peroxide vapor and a diluent gas formed by a mixture of oxygen and nitrogen.

5. The in-situ regeneration method according to claim 4, characterized in that: In the diluent gas, the volume ratio of oxygen to nitrogen is (5-90): (10～95)。 6. The in-situ regeneration method according to claim 1, wherein: The temperature of the second reduction treatment is 100-300°C; And / or, the pressure of the second reduction treatment is 1 to 5 bar; And / or, the second reduction treatment time is 2 to 10 hours; And / or, the reducing atmosphere is selected from one or both of hydrogen and synthesis gas, and a diluent gas formed by a mixture of one or both of hydrogen and synthesis gas and nitrogen.

7. The in-situ regeneration method according to claim 6, characterized in that: The synthesis gas is hydrogen and carbon monoxide; And / or, the reducing atmosphere is a diluent gas formed by mixing synthesis gas and nitrogen.

8. The in-situ regeneration method according to claim 7, characterized in that: In the dilution gas, the volume ratio of the synthesis gas to nitrogen is (10-50): (50-90); And / or, the volume ratio of hydrogen to carbon monoxide is (1-3):

1.

9. The in-situ regeneration method according to any one of claims 1 to 8, characterized in that: The ruthenium-based catalyst is a supported metal ruthenium catalyst, which at least comprises ruthenium metal oxide and a carrier.

10. The in-situ regeneration method according to claim 9, characterized in that: Based on the mass of the carrier, the mass of the ruthenium element in the ruthenium metal oxide is 0.1wt% to 15wt%; the ruthenium-based catalyst also contains copper metal oxide; based on the mass of the carrier, the mass of the copper element in the copper metal oxide does not exceed 30wt%.

Images