A deep purification desulfurization catalyst for synthesis gas and a preparation method thereof

Abstract

The application relates to the technical field of catalysts, and particularly discloses a deep purification desulfurization catalyst for synthesis gas and a preparation method thereof. The deep purification desulfurization catalyst for synthesis gas comprises a carrier component and an active component, the active component comprises raw materials in the following proportions by weight: 30-40 parts of copper oxide, 20-24 parts of zinc oxide, 12-20 parts of aluminum oxide, 5-15 parts of rare earth oxide and 3-10 parts of yttrium-doped zirconium oxide; and the carrier component comprises raw materials in the following proportions by weight: 30-50 parts of titanium carbide, 10-18 parts of hydroxylated boron nitride, 25-35 parts of gamma-aluminum oxide, 15-25 parts of pure calcium aluminate, 5-15 parts of modified diatomite and 6-8 parts of a crystal lattice stabilizer. The desulfurization catalyst has high desulfurization precision and structural stability by the proportioning design of the active component and the carrier component, and the high-temperature resistance and the erosion resistance of the desulfurization catalyst are improved.

Description

Technical Field

[0001] This application relates to the field of catalyst technology, and more specifically, to a deep purification and desulfurization catalyst for syngas and a method for preparing the same. Background Technology

[0002] In many chemical production processes, such as coal-to-natural-gas conversion, syngas is a crucial intermediate product. Syngas can be converted into methane using a methanation catalyst, thus producing natural gas. Syngas is mainly composed of carbon monoxide (CO), carbon dioxide (CO2), and hydrogen (H2), and also contains a certain amount of impurities such as sulfides. These sulfides not only poison the methanation catalyst in subsequent processes, reducing its activity and lifespan, but also lead to a decline in product quality and even cause equipment corrosion during production, seriously affecting the stability and economic efficiency of the entire production process. Therefore, deep purification and desulfurization of syngas to remove sulfide impurities is a necessary step to ensure the smooth operation of chemical production.

[0003] Currently, various types of catalysts and their preparation methods have been developed in the field of deep purification and desulfurization of syngas. Common desulfurization catalysts can be broadly classified into conventional desulfurizers and fine desulfurizers based on their composition and mechanism of action. For conventional desulfurizers, zinc oxide desulfurizers, due to their high sulfur capacity, can effectively adsorb sulfides in syngas under certain conditions, thereby extending the catalyst's lifespan, and are used in the upper layer of desulfurization units. Among fine desulfurizers, the copper-zinc-aluminum series of ultra-fine desulfurization catalysts is a typical example, usually packed in the lower layer of the desulfurization unit. This copper-based catalyst has a good hydrogenation effect on organic sulfur, further promoting the conversion and absorption of organic sulfur, ensuring that the total sulfur content at the outlet meets standards. In terms of preparation methods, for copper-based catalysts, the copper oxide content is generally controlled within a certain range (e.g., 15%-50%) to effectively avoid side reactions while considering the catalyst's sulfur capacity and other properties.

[0004] However, existing syngas deep purification desulfurization catalysts still have some shortcomings that urgently need to be addressed in practical applications. On the one hand, their high-temperature resistance is poor. With the continuous optimization of coal-to-natural gas projects, the CO2 concentration after syngas conversion increases, placing higher demands on the overall process environment temperature. The limitation of some desulfurization catalysts operating at temperatures generally below 200℃ is no longer sufficient to meet actual production needs. Under high-temperature environments, existing desulfurization catalysts are prone to problems such as reduced activity and structural damage, resulting in a significant reduction in desulfurization efficiency and an inability to consistently guarantee the desulfurization requirement of an outlet concentration below 20 ppb. On the other hand, existing desulfurization catalysts suffer from poor erosion resistance. During the continuous passage of syngas through the desulfurization unit, the catalyst is subjected to the erosion effect of the airflow. After long-term operation, some catalysts are prone to wear and breakage, which not only affects the service life of the catalyst itself but also leads to increased pressure drop in the desulfurization unit, affecting the stable operation of the entire syngas purification system. Therefore, how to develop a deep purification desulfurization catalyst for syngas with both good high-temperature resistance and excellent erosion resistance has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] To improve the high-temperature resistance and erosion resistance of desulfurization catalysts for syngas, this application provides a deep purification desulfurization catalyst for syngas and its preparation method.

[0006] The deep purification and desulfurization catalyst for syngas provided in this application adopts the following technical solution:

[0007] A deep purification and desulfurization catalyst for syngas includes a support component and an active component, wherein the active component comprises the following raw materials in parts by weight:

[0008] 30-40 parts copper oxide;

[0009] 20-24 parts zinc oxide;

[0010] 12-20 parts of aluminum oxide;

[0011] 5-15 parts of rare earth oxides;

[0012] 3-10 parts of yttrium-doped zirconium oxide;

[0013] The carrier component comprises the following raw materials in parts by weight:

[0014] 30-50 parts of titanium carbide;

[0015] 10-18 parts of hydroxylated boron nitride;

[0016] 25-35 parts of γ-alumina;

[0017] 15-25 parts of pure calcium aluminate;

[0018] 5-15 parts of modified diatomaceous earth;

[0019] 6-8 parts of lattice stabilizer.

[0020] By adopting the above technical solution, yttrium-doped zirconium oxide in the active component forms a bifunctional system of "anti-sintering-sulfide activation" with rare earth oxides (CeO2 / La2O3). 3+ Doping creates oxygen vacancies, which firmly anchor CuO active particles, inhibiting their migration and aggregation at high temperatures, thus preventing the loss of active sites. Simultaneously, the oxygen vacancies in yttrium-doped zirconium oxide can adsorb and activate organic sulfur compounds such as COS and thiophene, converting them into H2S, which is easily adsorbed by CuO, thus solving the problem of low efficiency in organic sulfur removal by traditional catalysts. Rare earth oxides (CeO2 / La2O3) further assist in preventing sintering: the oxygen storage / release capacity of CeO2 can alleviate Cu oxidation at high temperatures, while La2O3 forms a solid solution structure with CuO and ZnO, doubly inhibiting the crystallization and growth of active components. Ultimately, this increases the upper limit of the catalyst's applicable temperature from 200℃ to over 400℃, meeting the high-temperature process requirements under high CO2 concentrations after syngas shift reaction.

[0021] In the support components, titanium carbide (TiC) serves as the core rigid framework, with a hardness far exceeding that of traditional SiC, directly resisting the impact of syngas flow. Simultaneously, its thermal conductivity is more than 10 times that of γ-alumina, enabling rapid conduction of localized heat within the bed and preventing particle cracking caused by thermal stress. Hydroxylated boron nitride, as a toughening reinforcing phase, absorbs the energy of the flow impact through its layered structure, alleviating mechanical stress through interlayer slip and significantly improving the catalyst's fracture strength. Furthermore, the hydroxyl groups on the surface of hydroxylated boron nitride form hydrogen bonds and chemical bonds with γ-alumina and TiC, firmly "weaving" the support components into a network structure, forming a composite support structure that is "hard but not brittle, tough and wear-resistant." This structure maintains particle integrity even under long-term flow erosion, significantly improving the catalyst's erosion resistance. Modified diatomaceous earth, with its low-density characteristics, reduces the overall density of the catalyst, decreasing particle kinetic energy during flow impact and further mitigating erosion damage. The synergistic effect of these three components significantly enhances the catalyst's mechanical strength and erosion resistance, ensuring the catalyst's long-term operational stability.

[0022] In summary, the technical solution of this application balances desulfurization precision and structural stability through the ratio design of active components and carrier components, which fully improves the high temperature resistance and erosion resistance of the desulfurization catalyst, and can stably guarantee the desulfurization requirement of outlet concentration below 20 ppb, thus meeting the needs of deep purification of syngas.

[0023] Optionally, the yttrium-doped zirconium oxide is prepared by the following method:

[0024] (1) Zirconium oxychloride and yttrium nitrate were added to deionized water and stirred at 50-60℃ for 30-40 min. Then, the mixture was sonicated for 20-30 min to obtain a salt solution. Then, ammonium carbonate solution was added dropwise to the salt solution at a rate of 1-2 mL / min under constant temperature stirring at 60-70℃. After the addition was completed, the mixture was stirred for 1-2 h and then aged for 4-6 h. Then, the mixture was filtered, washed and dried to obtain yttrium-doped zirconium oxide precursor powder.

[0025] (2) Place the yttrium-doped zirconium oxide precursor powder into a muffle furnace and keep it at 250-300℃ for 2-3 hours; then keep it at 550-600℃ for 2-3 hours; then keep it at 1000-1100℃ for 4-5 hours and cool it naturally to room temperature to obtain yttrium-doped zirconium oxide.

[0026] By employing the above technical solution, yttrium-doped zirconium oxide precursor powder was first prepared, and then subjected to multi-stage heating and holding treatments to finally obtain high-performance yttrium-doped zirconium oxide. This precise preparation process ensures that the yttrium-doped zirconium oxide has a suitable oxygen vacancy concentration and crystal structure, thereby better exerting its functions of anchoring copper oxide active particles, activating sulfides, and enhancing high-temperature desulfurization activity, further guaranteeing the overall stability and high efficiency of the catalyst.

[0027] Optionally, the mass ratio of zirconium oxychloride, yttrium nitrate and deionized water is 1:(0.08-0.2):(3-5).

[0028] By adopting the above technical solution, the material mass ratio can ensure that all raw materials react fully during the preparation of yttrium-doped zirconium oxide, forming a uniform and stable salt solution. This ensures that the yttrium doping amount in the final yttrium-doped zirconium oxide is moderate and the oxygen vacancy concentration meets the requirements. This is beneficial for synergistic effects with active components such as copper oxide, enhancing the catalyst's adsorption and conversion capacity for sulfides and improving the catalyst's desulfurization effect.

[0029] Optionally, the mass concentration of the ammonium carbonate solution is 10%-15%, and the mass ratio of the ammonium carbonate solution to zirconium oxychloride is (4-8):1.

[0030] Optionally, the rare earth oxide is a mixture of cerium oxide and lanthanum oxide, with a mass ratio of cerium oxide to lanthanum oxide of 1:(0.5-2).

[0031] By adopting the above technical solution, the rare earth oxide is identified as a mixture of cerium oxide and lanthanum oxide, and their mass ratio is specified. Mixing cerium oxide and lanthanum oxide in a specific mass ratio allows for the full utilization of their respective properties, more effectively promoting the adsorption and oxidation of sulfides through an oxygen vacancy mechanism, while better suppressing the sintering of active components at high temperatures, maintaining the number of active sites on the catalyst surface, and further improving the catalyst's desulfurization performance and high-temperature stability.

[0032] Optionally, the hydroxylated boron nitride is prepared by the following method:

[0033] Layered boron nitride was ultrasonically dispersed in deionized water for 30-40 min to obtain a boron nitride suspension. Then, hydrogen peroxide solution was added to the boron nitride suspension, and the pH of the system was adjusted to 9-10 with ammonia. The temperature was then raised to 60-80℃ and stirred at a constant temperature for 4-6 h. The mixture was then vacuum filtered, and the filter cake was washed with deionized water until the pH of the filtrate was 7.0±0.2. Subsequently, it was placed in a forced-air drying oven and dried at 80-100℃ for 8-12 h to obtain hydroxylated boron nitride.

[0034] By employing the above-mentioned technical solution, layered boron nitride is prepared through ultrasonic dispersion, addition of hydrogen peroxide solution, pH adjustment, and constant-temperature stirring at a certain temperature. This preparation method successfully introduces hydroxyl groups onto the surface of boron nitride, forming a layered structure similar to a "nanopoucher," thereby effectively absorbing the impact energy of airflow, solving the problem of the carrier being "hard and brittle," and simultaneously enhancing the binding force with other carrier components, improving the carrier's erosion resistance and overall stability.

[0035] Optionally, the mass ratio of layered boron nitride to deionized water is 1:(10-20); the mass concentration of the hydrogen peroxide solution is 25%-30%, and the mass ratio of the amount of hydrogen peroxide solution added to the mass of layered boron nitride is (2-4):1.

[0036] By adopting the above technical solution, the appropriate ratio can ensure that the layered boron nitride is fully dispersed in deionized water, and the hydrogen peroxide solution can effectively hydroxylate and modify the boron nitride, so that the prepared hydroxylated boron nitride has an ideal layered structure and surface properties, better exert its toughness reinforcement and bonding enhancement effect in the support, and improve the catalyst's erosion resistance.

[0037] Optionally, the modified diatomaceous earth is prepared using the following method:

[0038] Diatomaceous earth, γ-aminopropyltriethoxysilane and ethanol solution were mixed at a mass ratio of 1:(0.05-0.2):(3-5), stirred at a constant temperature of 50-60℃ for 3-4 hours, filtered and dried at 60-90℃ to obtain modified diatomaceous earth.

[0039] By adopting the above technical solution, the above preparation method can modify the surface of diatomaceous earth, enhance its binding ability with other carrier components, and at the same time, its low density characteristics can reduce the overall density of the catalyst, reduce the impact kinetic energy of the airflow, and further enhance the erosion resistance and overall mechanical strength of the carrier.

[0040] Optionally, the lattice stabilizer is at least one of magnesium oxide and calcium oxide.

[0041] Secondly, this application provides a method for preparing a deep purification and desulfurization catalyst for syngas, employing the following technical solution:

[0042] A method for preparing a deep purification and desulfurization catalyst for syngas includes the following steps:

[0043] S1. Titanium carbide, hydroxylated boron nitride, γ-alumina, pure calcium aluminate, modified diatomaceous earth, and lattice stabilizer are mixed to obtain a mixture. Deionized water accounting for 8%-12% of the total mass of the mixture is added, stirred evenly, shaped, dried, and calcined to obtain carrier particles.

[0044] S2. Copper oxide, zinc oxide, aluminum oxide, rare earth oxides and yttrium-doped zirconium oxide are mixed and dissolved in deionized water, and ultrasonically dispersed for 30-40 minutes to obtain an active slurry;

[0045] S3. Immerse the carrier particles in the active slurry at 50-70℃ for 4-8 hours, filter, dry at 80-120℃ for 8-12 hours, and then calcine at 450-550℃ for 3-5 hours. After calcination, introduce a hydrogen-nitrogen mixture with a hydrogen gas fraction of 5%-10%, then reduce at 280-320℃ for 3-5 hours, and finally passivate with nitrogen containing 1-3 vol% oxygen for 2-3 hours to obtain a deep purification desulfurization catalyst.

[0046] First, various support components are mixed, stirred with water to form a granulated mixture, dried, and calcined to obtain support particles, providing a stable support base for the active components. Then, the active components are mixed, dissolved in water, and ultrasonically dispersed to obtain an active slurry, ensuring uniform dispersion of the active components. Next, the support particles are immersed in the active slurry for impregnation, drying, and calcination, ensuring the active components are firmly loaded onto the support. Finally, the catalyst performance is further optimized through reduction with a hydrogen-nitrogen mixed gas and passivation with an oxygen-containing nitrogen gas. This preparation method ensures that the active components and the support are fully integrated, forming a high-performance deep purification desulfurization catalyst with excellent properties such as high-temperature resistance and erosion resistance.

[0047] In summary, this application has the following beneficial effects:

[0048] 1. This application significantly improves the high-temperature resistance of the desulfurization catalyst. In the active component of the deep purification desulfurization catalyst of this application, yttrium-doped zirconium oxide and rare earth oxides (CeO2 / La2O3) form a bifunctional system of "anti-sintering-sulfide activation". Yttrium-doped zirconium oxide, through Y... 3+Doping creates oxygen vacancies, anchoring CuO active particles and inhibiting their migration and aggregation at high temperatures, thus preventing the loss of active sites and adsorbing activated organic sulfur. Rare earth oxides assist in preventing sintering, CeO2's oxygen storage / release capacity alleviates Cu oxidation, and La2O3 forms a solid solution structure with CuO and ZnO, doubly inhibiting the crystallization and growth of active components. This series of effects raises the upper limit of the catalyst's applicable temperature from 200℃ to over 400℃, meeting the high-temperature process requirements under high CO2 concentrations after syngas shift reaction and ensuring the stable operation of chemical production in high-temperature environments.

[0049] 2. This application effectively enhances the erosion resistance of the desulfurization catalyst. In the support components of this application, titanium carbide (TiC) serves as the core rigid framework, with a hardness far exceeding that of traditional SiC, directly resisting the impact of syngas flow. Its high thermal conductivity allows for rapid heat transfer, preventing particle cracking caused by thermal stress. Hydroxylated boron nitride acts as a toughening reinforcing phase; its layered structure absorbs the energy of the gas flow impact, alleviating mechanical stress through interlayer slip and improving the catalyst's fracture strength. Its surface hydroxyl groups form hydrogen bonds and chemical bonds with γ-alumina and TiC, creating a highly wear-resistant and tough composite support structure. Modified diatomaceous earth, with its low density, reduces the overall density of the catalyst, decreasing particle kinetic energy during gas flow impact. The synergistic effect of these three components significantly improves the catalyst's mechanical strength and erosion resistance, maintaining particle integrity even under long-term gas flow erosion and ensuring long-term stable operation of the catalyst.

[0050] 3. This application specifies in detail the preparation methods of each component. For example, yttrium-doped zirconium oxide is first prepared as a precursor powder, then subjected to multi-stage heating and holding treatment to ensure it has a suitable oxygen vacancy concentration and crystal structure; hydroxylated boron nitride is introduced with hydroxyl groups through specific operations to form an ideal layered structure; modified diatomaceous earth is obtained by mixing, stirring, and drying in a specific ratio. In the overall catalyst preparation, multiple support components are first mixed, shaped, dried, and calcined to obtain support particles, then the active components are mixed and dispersed to form a slurry. The support particles are impregnated with the slurry and then subjected to drying, calcination, reduction, and passivation treatment. This precise preparation process ensures that the active components and the support are fully combined, enabling the catalyst to balance desulfurization precision and structural stability, stably guaranteeing the desulfurization requirement of an outlet concentration below 20 ppb, and meeting the needs of deep purification of syngas. Attached Figure Description

[0051] Figure 1 This is a scanning electron microscope image of the desulfurization catalyst prepared in Example 1 of this application;

[0052] Figure 2 This is a scanning electron microscope image of the desulfurization catalyst prepared in Example 2 of this application;

[0053] Figure 3 This is a scanning electron microscope image of the desulfurization catalyst prepared in Example 3 of this application. Detailed Implementation

[0054] The present application will be further described in detail below with reference to the embodiments.

[0055] Example of yttrium-doped zirconium oxide preparation:

[0056] Preparation Example 1

[0057] Yttrium-doped zirconium oxide was prepared using the following method:

[0058] (1) Add 100g zirconium oxychloride and 8g yttrium nitrate to 300g deionized water, stir at 50℃ for 40min, then sonicate for 20min to obtain a salt solution, and then add ammonium carbonate solution dropwise to the salt solution at a rate of 1mL / min under constant temperature stirring at 60℃. The mass concentration of the ammonium carbonate solution is 10%, and the total amount of ammonium carbonate added is 800g. After the dropwise addition is completed, stir for 1h, then age for 4h, filter by vacuum filtration, wash the filtered precipitate with deionized water 5 times, and then dry it at 80℃ for 8h to obtain yttrium-doped zirconium oxide precursor powder.

[0059] (2) The yttrium-doped zirconium oxide precursor powder was placed in a muffle furnace and kept at 250°C for 3 hours; then kept at 550°C for 3 hours; then kept at 1000°C for 5 hours and naturally cooled to room temperature to obtain yttrium-doped zirconium oxide.

[0060] Preparation Example 2

[0061] Yttrium-doped zirconium oxide was prepared using the following method:

[0062] (1) 100g zirconium oxychloride and 14g yttrium nitrate were added to 400g deionized water and stirred at 55℃ for 35min. Then, the mixture was sonicated for 25min to obtain a salt solution. Then, ammonium carbonate solution was added dropwise to the salt solution at a rate of 1.5mL / min under constant temperature stirring at 65℃. The mass concentration of the ammonium carbonate solution was 12.5%, and the total amount of ammonium carbonate added was 600g. After the addition was completed, the mixture was stirred for 1.5h and then aged for 5h. The mixture was then filtered by vacuum filtration. The precipitate was washed 5 times with deionized water and then dried at 90℃ for 8h to obtain yttrium-doped zirconium oxide precursor powder.

[0063] (2) The yttrium-doped zirconium oxide precursor powder was placed in a muffle furnace and kept at 275°C for 2.5 h; then kept at 575°C for 2.5 h; then kept at 1050°C for 4.5 h, and naturally cooled to room temperature to obtain yttrium-doped zirconium oxide.

[0064] Preparation Example 3

[0065] Yttrium-doped zirconium oxide was prepared using the following method:

[0066] (1) 100g zirconium oxychloride and 20g yttrium nitrate were added to 500g deionized water and stirred at 60℃ for 30min. Then, the mixture was sonicated for 30min to obtain a salt solution. Then, ammonium carbonate solution was added dropwise to the salt solution at a rate of 2mL / min under constant temperature stirring at 70℃. The mass concentration of the ammonium carbonate solution was 15%, and the total amount of ammonium carbonate added was 400g. After the addition was completed, the mixture was stirred for 2h and then aged for 6h. The mixture was filtered by vacuum filtration. The precipitate was washed 5 times with deionized water and then dried at 100℃ for 6h to obtain yttrium-doped zirconium oxide precursor powder.

[0067] (2) The yttrium-doped zirconium oxide precursor powder was placed in a muffle furnace and kept at 300°C for 2 hours; then kept at 600°C for 2 hours; then kept at 1100°C for 4 hours and naturally cooled to room temperature to obtain yttrium-doped zirconium oxide.

[0068] Example of preparation of hydroxylated boron nitride:

[0069] Preparation Example 4

[0070] Hydroxylated boron nitride was prepared by the following method:

[0071] 10g of 200-mesh layered boron nitride was added to 100g of deionized water and ultrasonically dispersed at 300W for 40min to obtain a boron nitride suspension. Then, 20g of 30% hydrogen peroxide solution was added to the boron nitride suspension, and the pH of the system was adjusted to 9 with ammonia. The temperature was then raised to 60℃ and stirred at a constant temperature for 6h. The mixture was then vacuum filtered, and the filter cake was washed with deionized water until the pH of the filtrate was 7.0±0.2. Subsequently, it was placed in a forced-air drying oven and dried at 80℃ for 12h to obtain hydroxylated boron nitride.

[0072] Preparation Example 5

[0073] Hydroxylated boron nitride was prepared by the following method:

[0074] 10g of 200-mesh layered boron nitride was added to 150g of deionized water and ultrasonically dispersed at 400W for 35min to obtain a boron nitride suspension. Then, 30g of 27% hydrogen peroxide solution was added to the boron nitride suspension, and the pH of the system was adjusted to 9.5 with ammonia. The temperature was then raised to 70℃ and stirred at a constant temperature for 5h. The mixture was then vacuum filtered, and the filter cake was washed with deionized water until the pH of the filtrate was 7.0±0.2. The filtrate was then placed in a forced-air drying oven and dried at 90℃ for 10h to obtain hydroxylated boron nitride.

[0075] Preparation Example 6

[0076] Hydroxylated boron nitride was prepared by the following method:

[0077] 10g of 200-mesh layered boron nitride was added to 200g of deionized water and ultrasonically dispersed at 500W for 30min to obtain a boron nitride suspension. Then, 40g of 25% hydrogen peroxide solution was added to the boron nitride suspension, and the pH of the system was adjusted to 10 with ammonia. The temperature was then raised to 80℃ and stirred at a constant temperature for 4h. The mixture was then vacuum filtered, and the filter cake was washed with deionized water until the pH of the filtrate was 7.0±0.2. Subsequently, it was placed in a forced-air drying oven and dried at 100℃ for 8h to obtain hydroxylated boron nitride.

[0078] Example of preparation of modified diatomaceous earth:

[0079] Preparation Example 7

[0080] Modified diatomaceous earth is prepared by the following method:

[0081] Diatomaceous earth, γ-aminopropyltriethoxysilane, and ethanol solution were mixed at a mass ratio of 1:0.05:3, wherein the mass concentration of the ethanol solution was 20%. The mixture was stirred at a constant temperature of 50°C for 4 hours, filtered, and dried at 60°C for 6 hours to obtain modified diatomaceous earth.

[0082] Preparation Example 8

[0083] Modified diatomaceous earth is prepared by the following method:

[0084] Diatomaceous earth, γ-aminopropyltriethoxysilane, and ethanol solution were mixed at a mass ratio of 1:0.12:4, with the ethanol solution having a mass concentration of 25%. The mixture was stirred at a constant temperature of 55°C for 3.5 hours, filtered, and then dried at 75°C for 5 hours to obtain modified diatomaceous earth.

[0085] Preparation Example 9

[0086] Modified diatomaceous earth is prepared by the following method:

[0087] Diatomaceous earth, γ-aminopropyltriethoxysilane, and ethanol solution were mixed at a mass ratio of 1:0.2:5, with the ethanol solution having a mass concentration of 30%. The mixture was stirred at a constant temperature of 60°C for 3 hours, filtered, and then dried at 90°C for 4 hours to obtain modified diatomaceous earth.

[0088] Example

[0089] Example 1

[0090] A deep purification and desulfurization catalyst for syngas comprises a support component and an active component. The raw material components and amounts of the support and active components are shown in Table 1. In the active component, the rare earth oxide is a homogeneous mixture of cerium oxide and lanthanum oxide at a mass ratio of 1:0.5; the yttrium-doped zirconium oxide is the yttrium-doped zirconium oxide prepared in Preparation Example 1. In the support component, the hydroxylated boron nitride is the hydroxylated boron nitride prepared in Preparation Example 4; the modified diatomaceous earth is the modified diatomaceous earth prepared in Preparation Example 7; and the lattice stabilizer is magnesium oxide.

[0091] A deep purification and desulfurization catalyst for syngas is prepared by the following method:

[0092] S1. Titanium carbide, hydroxylated boron nitride, γ-alumina, pure calcium aluminate, modified diatomaceous earth, and lattice stabilizer are mixed to obtain a mixture. Deionized water accounting for 8% of the total mass of the mixture is added, stirred evenly, and then shaped. After drying and calcination, carrier particles are obtained.

[0093] S2. Copper oxide, zinc oxide, aluminum oxide, rare earth oxides and yttrium-doped zirconium oxide are mixed and dissolved in deionized water, and ultrasonically dispersed for 30 min to obtain an active slurry;

[0094] S3. The carrier particles are immersed in the active slurry and impregnated at 50°C for 8 hours. After filtration, they are dried at 80°C for 12 hours and then calcined at 450°C for 5 hours. After calcination, a hydrogen-nitrogen mixture is introduced with a hydrogen gas fraction of 5%. Then, the mixture is reduced at 280°C for 5 hours and finally passivated with nitrogen containing 1 vol% oxygen for 3 hours to obtain a deep purification desulfurization catalyst.

[0095] Example 2

[0096] A deep purification and desulfurization catalyst for syngas comprises a support component and an active component. The raw material components and amounts of the support and active components are shown in Table 1. In the active component, the rare earth oxide is a homogeneous mixture of cerium oxide and lanthanum oxide at a mass ratio of 1:1.2; the yttrium-doped zirconium oxide is the yttrium-doped zirconium oxide prepared in Preparation Example 2. In the support component, the hydroxylated boron nitride is the hydroxylated boron nitride prepared in Preparation Example 5; the modified diatomaceous earth is the modified diatomaceous earth prepared in Preparation Example 8; and the lattice stabilizer is calcium oxide.

[0097] A deep purification and desulfurization catalyst for syngas is prepared by the following method:

[0098] S1. Titanium carbide, hydroxylated boron nitride, γ-alumina, pure calcium aluminate, modified diatomaceous earth, and lattice stabilizer are mixed to obtain a mixture. Deionized water accounting for 10% of the total mass of the mixture is added, stirred evenly, and then shaped. After drying and calcination, carrier particles are obtained.

[0099] S2. Copper oxide, zinc oxide, aluminum oxide, rare earth oxides and yttrium-doped zirconium oxide are mixed and dissolved in deionized water, and ultrasonically dispersed for 35 min to obtain an active slurry;

[0100] S3. The carrier particles are immersed in the active slurry and soaked at 60°C for 6 hours. After filtration, they are dried at 100°C for 10 hours and then calcined at 500°C for 4 hours. After calcination, a hydrogen-nitrogen mixture is introduced with a hydrogen gas fraction of 8%. Then, the mixture is reduced at 300°C for 4 hours and finally passivated with nitrogen containing 2 vol% oxygen for 2.5 hours to obtain a deep purification desulfurization catalyst.

[0101] Example 3

[0102] A deep purification and desulfurization catalyst for syngas comprises a support component and an active component. The raw material components and their amounts for both the support and active components are shown in Table 1. In the active component, the rare earth oxide is a homogeneous mixture of cerium oxide and lanthanum oxide at a mass ratio of 1:2; the yttrium-doped zirconium oxide is the yttrium-doped zirconium oxide prepared in Preparation Example 3. In the support component, the hydroxylated boron nitride is the hydroxylated boron nitride prepared in Preparation Example 6; the modified diatomaceous earth is the modified diatomaceous earth prepared in Preparation Example 9; and the lattice stabilizer is calcium oxide.

[0103] A deep purification and desulfurization catalyst for syngas is prepared by the following method:

[0104] S1. Titanium carbide, hydroxylated boron nitride, γ-alumina, pure calcium aluminate, modified diatomaceous earth, and lattice stabilizer are mixed to obtain a mixture. Deionized water accounting for 12% of the total mass of the mixture is added, stirred evenly, and then shaped. After drying and calcination, carrier particles are obtained.

[0105] S2. Copper oxide, zinc oxide, aluminum oxide, rare earth oxides and yttrium-doped zirconium oxide are mixed and dissolved in deionized water, and ultrasonically dispersed for 40 min to obtain an active slurry;

[0106] S3. The carrier particles are immersed in the active slurry and soaked at 70°C for 4 hours. After filtration, they are dried at 120°C for 8 hours and then calcined at 550°C for 3 hours. After calcination, a hydrogen-nitrogen mixture is introduced with a hydrogen gas fraction of 10%. Then, the mixture is reduced at 320°C for 3 hours and finally passivated with nitrogen containing 3 vol% oxygen for 2 hours to obtain a deep purification desulfurization catalyst.

[0107] Table 1. Components and amounts (g) of the catalysts used in Examples 1-3

[0108]

[0109] Example 4

[0110] A deep purification and desulfurization catalyst for syngas differs from Example 1 in that the rare earth oxide used in this example is a single cerium oxide.

[0111] Example 5

[0112] A deep purification and desulfurization catalyst for syngas differs from Example 1 in that the lattice stabilizer in this example is a mixture of magnesium oxide and calcium oxide in a mass ratio of 1:1.

[0113] Comparative Example

[0114] Comparative Example 1

[0115] A deep purification and desulfurization catalyst for syngas differs from Example 5 in that an equal amount of zirconium oxide is used instead of yttrium-doped zirconium oxide in the active component of this comparative example.

[0116] Comparative Example 2

[0117] A deep purification and desulfurization catalyst for syngas differs from Example 5 in that an equal amount of boron nitride is used instead of hydroxylated boron nitride in the support component of this comparative example.

[0118] Comparative Example 3

[0119] A deep purification and desulfurization catalyst for syngas differs from Example 5 in that an equal amount of diatomaceous earth is used instead of modified diatomaceous earth in the carrier component of this comparative example.

[0120] Comparative Example 4

[0121] A deep purification and desulfurization catalyst for syngas differs from Example 5 in its preparation method. In this comparative example, oxygen-containing nitrogen gas was not used for passivation treatment of the reduced solid material in step S3. Specifically, step S3 in this comparative example is as follows:

[0122] The carrier particles were immersed in the active slurry and impregnated at 50°C for 8 hours. After filtration, they were dried at 80°C for 12 hours and then calcined at 450°C for 5 hours. After calcination, a hydrogen-nitrogen mixture was introduced, with the hydrogen gas fraction being 5%. The mixture was then reduced at 280°C for 5 hours to obtain a deep purification desulfurization catalyst.

[0123] Performance testing

[0124] The performance of the deep purification desulfurization catalysts prepared in Examples 1-5 and Comparative Examples 1-4 was tested.

[0125] 1. High temperature resistance test

[0126] Take 50g of catalyst particles from the examples / comparative examples and pack them into a quartz fixed-bed reactor with an inner diameter of 20mm and a bed height of 10cm; age the reactor at 450℃ under a N2 atmosphere for 200h, and retain the unaged catalyst from the same batch as a blank control; then introduce simulated synthesis gas containing H2S and COS (space velocity 3000h). -1 The desulfurization efficiency was measured by gas chromatography-PFPD. The activity retention rate was calculated as "desulfurization efficiency after aging / desulfurization efficiency before aging × 100%". The higher the activity retention rate, the better the high temperature resistance of the catalyst.

[0127] 2. Erosion resistance

[0128] Take 100g of catalyst and pack it into a fixed bed. Pass dry air through it at a flow rate of 10m / s for 100h. After rinsing, sieve the fine powder with a 100-mesh sieve and weigh the remaining intact particles. Calculate the wear rate according to "(initial mass - remaining mass) / initial mass × 100%". The lower the wear rate, the better the catalyst's erosion resistance.

[0129] 3. Desulfurization precision

[0130] 20g of catalyst was packed into a fixed bed, and a simulated synthesis gas containing H2S (300ppb), COS (80ppb), and thiophene (30ppb) was introduced (400℃, 1.0MPa, space velocity 3000h). -1 The system was run continuously for 48 hours, and the total sulfur at the outlet was measured by gas chromatography-CLD every 2 hours. The stable value recorded was the desulfurization accuracy.

[0131] 4. Mechanical strength

[0132] The test was conducted using a microcomputer-controlled electronic universal testing machine (WDW-5, Jinan Test Metal), equipped with a flat indenter (10mm in diameter) and a loading rate of 1mm / min. The test procedure was as follows: a single catalyst particle was placed in the center of the indenter, and pressure was applied at a uniform speed until the particle broke. The maximum pressure at the moment of breakage was recorded, and then the mechanical strength was calculated.

[0133] The results are shown in Table 2.

[0134] Table 2 Detection Results

[0135]

[0136] As can be seen from Table 2, the detection data of Examples 1-5 are all better than those of Comparative Examples 1-4, which fully verifies that the active component "yttrium-doped zirconium oxide + rare earth oxide" and the support component "TiC + hydroxylated boron nitride + modified diatomite" in the technical solution of this application can effectively improve the catalyst's high temperature resistance, erosion resistance, deep desulfurization and mechanical strength performance, which is in line with the core goal of "solving the high temperature deactivation and easy wear of traditional catalysts".

[0137] The activity retention rates of Examples 1-3 and Example 5 were all ≥96.9%, with Example 5 (mixed lattice stabilizer) reaching 98.4%. This indicates that the "yttrium-doped zirconium oxide + CeO2 / La2O3" dual-active system can effectively inhibit the high-temperature sintering of CuO. The oxygen vacancies of yttrium-doped zirconium oxide anchor Cu particles, and La2O3 forms a solid solution, synergistically maintaining active sites, thus effectively enhancing the catalyst's high-temperature resistance. It can maintain a long-term stable catalytic desulfurization effect even at 450℃. In Example 4, the use of a single cerium oxide resulted in a loss of activity retention rate, indicating a decrease in high-temperature resistance. This demonstrates that the rare earth oxide composite of CeO2 and La2O3 plays a crucial role in maintaining the catalyst's high-temperature resistance.

[0138] Comparative Example 1 used ordinary zirconium oxide instead of yttrium-doped zirconium oxide, and its activity retention rate at 450℃ was only 89.6%, due to the absence of Yttrium. 3+ The doped oxygen vacancies have weak resistance to sintering, thus reducing their high-temperature performance. Comparative Example 4 (without passivation treatment) only had an activity retention rate of 78.6% at 450℃. This was because Cu was exposed to oxidation after reduction, resulting in the loss of active sites, which proves the necessity of the passivation step for high-temperature activity retention.

[0139] The wear rates of Examples 1-5 were all ≤0.41%, which was much lower than that of the comparative example, indicating that the "TiC rigid skeleton + hydroxylated BN tough buffer + modified diatomaceous earth low density" worked synergistically. Among them, TiC resisted impact, hydroxylated BN absorbed energy through interlayer slip, and modified diatomaceous earth reduced particle kinetic energy, thus reducing wear.

[0140] Comparative Example 2 uses ordinary BN instead of hydroxylated BN, and its wear rate reaches 2.25%. Because ordinary BN has no surface hydroxyl groups, it cannot be firmly bonded to TiC / γ-alumina, and the carrier is easy to disintegrate. Comparative Example 3 uses ordinary diatomaceous earth instead of modified diatomaceous earth, and its wear rate reaches 1.39%. Because ordinary diatomaceous earth has weak bonding force with the carrier, it is easily washed away by airflow.

[0141] Examples 1-3 and 5 achieved a desulfurization accuracy of ≤6.1ppb, far exceeding the requirement of "≤20ppb". This is because yttrium-doped zirconium oxide can activate organic sulfur (converting it into easily adsorbed hydrogen sulfide), and combined with copper oxide-zinc oxide adsorption, it achieves deep removal. Example 4 (using only cerium oxide) achieved 9.6ppb. Due to the lack of lanthanum oxide to assist in the activation of organic sulfur, the accuracy was slightly reduced, but it is still better than traditional catalysts.

[0142] In Comparative Example 1, ordinary zirconium oxide was used instead of yttrium-doped zirconium oxide, and its desulfurization accuracy reached 26.3 ppb. However, because ordinary zirconium oxide does not have enough oxygen vacancies to activate organic sulfur, it can only remove hydrogen sulfide and cannot meet the requirements for deep purification.

[0143] The mechanical strength of Examples 1-5 is ≥190.6 MPa, meeting the requirements of "resistance to compression and fracture". This is attributed to the high hardness of titanium carbide, the bonding and strengthening effect of pure calcium aluminate, and the strong chemical bond between modified diatomite and other carrier components, resulting in a stable overall structure. In Comparative Example 2, ordinary boron nitride was used instead of hydroxylated boron nitride, and in Comparative Example 3, ordinary diatomite was used instead of modified diatomite. The final catalyst strengths decreased to 155.4 MPa and 163.7 MPa, respectively, due to the weak bonding of the carrier components and poor structural integrity. This demonstrates the supporting role of hydroxylated boron nitride and modified diatomite in improving mechanical strength.

[0144] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A deep clean-up desulfurization catalyst for synthesis gas comprising a support component and an active component, characterized in that, The active component comprises raw materials in the following proportions by weight: copper oxide 30-40 parts; zinc oxide 20-24 parts; aluminum oxide 12-20 parts; rare earth oxide 5-15 parts; yttrium-doped zirconium oxide 3-10 parts; the carrier component comprises raw materials in the following proportions by weight: titanium carbide 30-50 parts; hydroxylated boron nitride 10-18 parts; gamma-aluminum oxide 25-35 parts; pure calcium aluminate 15-25 parts; modified diatomite 5-15 parts; lattice stabilizer 6-8 parts; The rare earth oxide is a mixture of cerium oxide and lanthanum oxide; the lattice stabilizer is at least one of magnesium oxide and calcium oxide; The modified diatomite is prepared by the following method: The diatomite, gamma-aminopropyl triethoxysilane and ethanol solution are mixed in a mass ratio of 1: (0.05-0.2): (3-5), stirred at 50-60°C for 3-4h, dried at 60-90°C after filtration, and obtained. The catalyst preparation method comprises the following steps: S1, mixing titanium carbide, hydroxylated boron nitride, gamma-aluminum oxide, pure calcium aluminate, modified diatomite and lattice stabilizer to obtain a mixture, adding 8%-12% of deionized water based on the total mass of the mixture, uniformly stirring, shaping, drying and calcining to obtain carrier particles; S2, mixing copper oxide, zinc oxide, aluminum oxide, rare earth oxide and yttrium-doped zirconium oxide, dissolving in deionized water, ultrasonic dispersion for 30-40min to obtain active slurry; S3, immersing the carrier particles in the active slurry, immersing at 50-70°C for 4-8h, filtering, drying at 80-120°C for 8-12h, and then calcining at 450-550°C for 3-5h; after calcination, hydrogen and nitrogen mixed gas is introduced, the volume fraction of hydrogen is 5%-10%, then reduced at 280-320°C for 3-5h, and finally passivated with nitrogen containing 1-3vol% oxygen for 2-3h.

2. A deep purification desulfurization catalyst for synthesis gas according to claim 1, characterized by, The yttrium-doped zirconium oxide is prepared by the following method: (1) adding zirconium oxychloride and yttrium nitrate into deionized water, stirring at 50-60°C for 30-40min, then ultrasonic treatment for 20-30min to obtain a salt solution, then adding ammonium carbonate solution into the salt solution at a rate of 1-2mL / min under the condition of constant temperature stirring at 60-70°C, stirring for 1-2h after the addition is completed, then aging for 4-6h, then filtering, washing and drying to obtain yttrium-doped zirconium oxide precursor powder; (2) placing the yttrium-doped zirconium oxide precursor powder into a muffle furnace, keeping at 250-300°C for 2-3h, then keeping at 550-600°C for 2-3h, and then keeping at 1000-1100°C for 4-5h, and naturally cooling to room temperature to obtain yttrium-doped zirconium oxide.

3. A deep clean-up desulphurization catalyst for synthesis gas as claimed in claim 2, wherein: The mass ratio of zirconium oxychloride, yttrium nitrate and deionized water is 1: (0.08-0.2): (3-5).

4. A deep clean-up desulphurization catalyst for synthesis gas as claimed in claim 3, wherein: The mass concentration of the ammonium carbonate solution is 10%-15%, and the mass ratio of the ammonium carbonate solution to zirconium oxychloride is (4-8):

1.

5. A deep purification desulfurization catalyst for synthesis gas according to claim 1, characterized by: The mass ratio of cerium oxide to lanthanum oxide is 1: (0.5-2).

6. A deep purification desulfurization catalyst for synthesis gas according to claim 1, characterized by, The hydroxylated boron nitride is prepared by the following method: The layered boron nitride is added into deionized water and ultrasonically dispersed for 30-40 min to obtain a boron nitride suspension, then hydrogen peroxide solution is added into the boron nitride suspension, the pH of the system is adjusted to 9-10 by adding ammonia water, then the temperature is increased to 60-80℃, constant temperature stirring is carried out for 4-6 h, then the mixture is vacuum filtered, the filter cake is washed with deionized water until the pH of the filtrate is 7.0±0.2, then it is put into a blast drying oven and dried at 80-100℃ for 8-12 h to obtain the hydroxylated boron nitride.

7. A deep clean-up desulphurization catalyst for synthesis gas as claimed in claim 6, wherein: The mass ratio of the layered boron nitride to deionized water is 1: (10-20), the mass concentration of the hydrogen peroxide solution is 25%-30%, and the mass ratio of the hydrogen peroxide solution to the layered boron nitride is (2-4):1.

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