A deoxidizer and a method for preparing the same

Abstract

The application relates to the technical field of gas deoxidization, and particularly discloses a deoxidizer and a preparation method thereof. A preparation method of a deoxidizer comprises the following steps: S1: dissolving lanthanum salt, manganese salt and nickel salt in water, adding citric acid, adjusting pH, mixing under temperature rise, spray drying, heat preservation under temperature rise, switching the mixed gas of O2 and N2, sintering under temperature rise, and obtaining granules A; S2: dissolving cerium salt, manganese salt and nickel salt in water, adding citric acid, adjusting pH, mixing under temperature rise, spray drying, sintering under temperature rise, and obtaining granules B; S3: mixing the granules A and the granules B, grinding for 4-5 hours, adding a dispersing agent and water, uniformly mixing, adding magnesium modified ceramsite carriers, vacuum impregnating for 45-55 minutes, solid-liquid separation, drying, and heat preserving for 110-150 minutes under the mixed gas of H2 and N2 at 480-520 DEG C, and cooling to obtain the deoxidizer. The deoxidizer has excellent deoxidization capacity.

Description

Technical Field

[0001] This application relates to the technical field of gas deoxidation, and more specifically, to a deoxidizing agent and a method for preparing the same. Background Technology

[0002] Currently, commonly used gas purification deoxidizers are classified into catalytic hydrogenation deoxidizers and chemical absorption deoxidizers based on their deoxidation mechanism. Catalytic hydrogenation deoxidizers, in the presence of hydrogen, react with residual oxygen in the feed gas to form water, thus removing oxygen. They typically use noble metals such as Pd and Pt as active components, and Al2O3, TiO2, and SiO2 as supports. They offer high deoxidation precision and mild reaction conditions, generally removing oxygen from gases to very low levels at room temperature, but are expensive. Furthermore, because hydrogen is required for their use, this catalyst is currently mainly used in the electrolysis of hydrogen to produce high-purity hydrogen and inert gases. Chemical absorption deoxidizers typically use metals such as copper and manganese as active components, reacting chemically with oxygen to form oxides, thereby removing oxygen. However, their deoxidation effect is poor, exhibiting limitations in precision and capacity.

[0003] Patent application CN1342516A discloses a deoxidizer with MnO and CuO as active components. The specific preparation method is as follows (taking Example 3 as an example): Take 80 grams of MnCO3 and 10 grams of Al2O3, mix them thoroughly and crush them to a fineness of 500 mesh or higher, add an appropriate amount of 10% dilute nitric acid, process them into strips, and air dry them naturally; impregnate them with 10 grams of Cu(NO3)2 by weight, calcine them at 300°C for 6 hours under ventilated conditions, and then cool them naturally to room temperature for later use.

[0004] In this technical solution, MnCO3 and Al2O3 are directly mixed and pulverized by physical mixing. MnO generated from MnCO3 is prone to agglomeration due to uneven mixing, resulting in a reduced specific surface area and insufficient effective contact sites with oxygen. Although Cu(NO3)2 impregnation can penetrate into the interior of the carrier through capillary penetration, the uneven distribution of CuO due to the uneven pore structure of the carrier ultimately leads to a small deoxygenation capacity. Summary of the Invention

[0005] To improve deoxidation capacity, this application provides a deoxidizing agent and a method for preparing the same.

[0006] In a first aspect, this application provides a method for preparing a deoxidizer, employing the following technical solution:

[0007] A method for preparing a deoxidizer includes the following steps:

[0008] S1: Dissolve lanthanum salt, manganese salt and nickel salt in water with a molar ratio of 1:x:(1-x), add citric acid to adjust the pH to 5.5~6.0, heat to 75~85℃, mix for 90~120min, spray dry, first at 280~320℃ for 50~70min, switch to a mixture of O2 and N2, sinter at 720~760℃ for 3~3.5h to obtain granules A;

[0009] S2: Dissolve cerium salt, manganese salt and nickel salt in water with a molar ratio of 1:(0.04~0.06):(0.04~0.05), add citric acid to adjust the pH to 5.5~6.0, heat to 75~85℃, mix for 90~120min, spray dry, and sinter at 580~620℃ for 3~3.5h to obtain particles B;

[0010] S3: Mix particles A and B, grind for 4-5 hours, add dispersant and water, mix evenly, add magnesium-modified ceramic carrier, vacuum impregnate for 45-55 minutes, separate solid and liquid, dry, and keep warm at 480-520℃ for 110-150 minutes under a mixture of H2 and N2, then cool to obtain deoxidizer.

[0011] In this scheme, particle A, based on a specific La:Mn:Ni ratio, forms a stable metal-citric acid complex through pH adjustment. Spray drying locks in dispersion. After pre-decomposition, oxygen is precisely controlled using a specific ratio of oxygen-nitrogen mixed gas, leading to directional crystallization at a suitable temperature to form the main perovskite phase, ensuring efficient oxygen migration channels. Particle B, by limiting the Mn / Ni doping amount (≤10%), maintains the structural stability of the fluorite phase CeO2, ensuring that its lattice oxygen has appropriate activity. After mixing and grinding particles A and B, they are then vacuum impregnated onto a magnesium-modified ceramic support. Under a reducing atmosphere of H2 and N2, the CeO2 on the surface of particle B... 4+ Prioritize restoring to Ce 3+ This generates high concentrations of oxygen vacancies, and the released electrons are transferred to particle A through the interface, triggering the migration of oxygen ions from the perovskite-like phase to CeO2, forming a continuous oxygen vacancy gradient, driving cyclic deoxygenation, and effectively improving the deoxygenation rate and capacity.

[0012] Preferably, in step S1, the value range of x is 0.5 to 0.8.

[0013] Preferably, in step S1, the volume ratio of O2 to N2 in the O2 and N2 mixture is (15~20):(80~85).

[0014] Preferably, in step S3, the volume ratio of H2 to N2 in the H2 and N2 mixture is (5~10):(90~95).

[0015] Preferably, in step S3, the dispersant is polyvinylpyrrolidone.

[0016] Preferably, in step S3, the amount of dispersant used is 1.5% to 2.5% of the total mass of particles A and particles B.

[0017] Preferably, in step S3, the mass ratio of particle A to particle B is (3~4):3.

[0018] Preferably, in step S3, the ratio of the mass of magnesium-modified ceramic particles to the total mass of particles A, particles B and water is (1.5~2.5):1.

[0019] Preferably, the preparation method of the magnesium-modified ceramsite carrier includes the following steps:

[0020] Kaolin, pore-forming agent, and magnesium-modified molecular sieve were added to a reactor, kneaded with water until homogeneous, extruded, granulated, and dried. The mixture was then sintered at 550–600℃ for 1.5–2 h, followed by switching to an inert atmosphere and further heating to 1100–1150℃ for 2.5–3 h. After cooling, the mixture was immersed in nitric acid with a molar concentration of 0.15–0.2 mol / L, heated to 80–100℃, and acid-washed for 2–2.5 h. Solid-liquid separation was achieved, followed by washing until neutral. The mixture was then immersed in magnesium nitrate solution with a molar concentration of 0.6–0.8 mol / L and sonicated for 30–40 min. Solid-liquid separation was achieved, followed by washing, drying, and sintering at 550–600℃ for 1.5–2 h. After cooling, magnesium-modified ceramic particle carrier was obtained.

[0021] Preferably, the mass ratio of the kaolin, pore-forming agent and magnesium-modified molecular sieve is (6~6.5):2.5:(1~1.5).

[0022] In this scheme, the magnesium-modified ceramsite carrier forms a porous and stable structure through reasonable material formulation and step-by-step processing. After sintering to create pores, acid washing, and magnesium nitrate impregnation, raw materials such as kaolin provide ample loading space for the active particles, while magnesium regulates surface properties and enhances the bonding with the active particles. This not only ensures oxygen mass transfer and dispersion of active components but also helps construct an oxygen vacancy gradient, ultimately synergistically improving the efficiency and lifespan of the deoxidizer.

[0023] Preferably, the preparation method of the magnesium-modified molecular sieve includes the following steps:

[0024] SBA-15 molecular sieve was placed in a sintering furnace, heated to 550-600℃, held for 3.5-4 hours, cooled to room temperature, immersed in nitric acid with a molar concentration of 0.15-0.2 mol / L, heated to 80-100℃, acid washed for 3-4 hours, solid-liquid separation was achieved, washed until neutral, immersed in magnesium nitrate solution with a molar concentration of 0.6-0.8 mol / L, sonicated for 30-40 minutes, solid-liquid separation was achieved, washed, dried, sintered at 550-600℃ for 2.5-3 hours, and cooled to obtain magnesium-modified molecular sieve.

[0025] In this scheme, the preparation of magnesium-modified molecular sieve involves activating SBA-15 molecular sieve through high-temperature pretreatment, removing impurities and increasing surface active sites through nitric acid washing, followed by ultrasonic impregnation with magnesium nitrate to achieve uniform magnesium loading, and finally high-temperature sintering to transform magnesium into a stable active phase. This endows the molecular sieve with abundant magnesium active sites and suitable surface chemical properties. Its function is to introduce uniformly dispersed magnesium elements into the ceramsite support, strengthen the interfacial synergy between the support and the deoxidizing active particles, and ultimately promote the improvement of deoxidation performance together with the support and active components.

[0026] Preferably, in the preparation method of the magnesium-modified ceramsite carrier, after the magnesium-modified molecular sieve, the method further includes the step of adding alumina fibers, wherein the amount of alumina fibers is 3% to 4% of the total mass of kaolin, pore-forming agent and magnesium-modified molecular sieve.

[0027] In this scheme, the compressive strength of the ceramsite carrier is improved by the mechanical reinforcement effect of alumina fibers. Furthermore, because its fibrous structure can interweave with the ceramic skeleton to form a network, it can inhibit excessive pore collapse during sintering and help maintain the integrity of the porous structure of the carrier.

[0028] Preferably, in step S1, after adding nickel salt, a step of adding strontium salt is also included, wherein the molar ratio of lanthanum salt to strontium salt is 1:(0.1~0.2).

[0029] In this scheme, strontium salt is introduced into the preparation of particle A and a specific molar ratio of lanthanum and strontium is controlled. The doping effect of strontium ions is utilized: the ionic radius of strontium is close to that of lanthanum, and it can partially replace lanthanum. 3+ The formation of solid solutions increases the oxygen vacancy concentration through charge compensation mechanisms, further widening oxygen migration channels.

[0030] Preferably, in step S3, after particle B, a step of adding nano-strontium titanate is further included, wherein the amount of nano-strontium titanate is 3% to 5% of the total mass of particle A and particle B.

[0031] In this scheme, the nano-strontium titanate has a similar structure to particle A, forming a coherent interface and reducing the oxygen ion migration barrier.

[0032] Preferably, the nano-strontium titanate undergoes the following treatment steps before use:

[0033] Nano-strontium titanate and polyvinylpyrrolidone (PVP) were mixed evenly at a mass ratio of 1:(1~1.1), anhydrous ethanol was added, the mixture was ball-milled evenly, dried, and sieved to obtain pretreated nano-strontium titanate.

[0034] Secondly, this application provides a deoxidizer prepared by the above-described preparation method.

[0035] In summary, this application has the following beneficial effects:

[0036] This application synthesizes particles A and B in steps. After the two are combined, the resulting oxygen vacancy concentration gradient drives the directional migration of oxygen ions. Combined with the cycle of surface oxygen activation and lattice oxygen storage, the deoxidation rate and capacity are significantly improved. At the same time, relying on the porous structure of the carrier, the deoxidation performance and service life are synergistically improved. Attached Figure Description

[0037] Figure 1 The XRD pattern of the deoxidizer in Example 2 of this application;

[0038] Figure 2 The image shows the XRD pattern of the deoxidizer in Comparative Example 1 of this application. Detailed Implementation

[0039] The present application will be further described in detail below with reference to the embodiments.

[0040] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0041] The particle size distribution of nano-strontium titanate is 40~60nm;

[0042] The particle size distribution of alumina fibers is 5~20μm;

[0043] Kaolinite particle size distribution: 2~5μm;

[0044] SBA-15 molecular sieve has a particle size distribution of 1~5μm.

[0045] Example 1

[0046] The method for preparing the deoxidizer in this embodiment includes the following steps:

[0047] S1: Dissolve 0.1 mol of lanthanum nitrate hexahydrate, 0.08 mol of manganese nitrate tetrahydrate, and 0.02 mol of nickel nitrate hexahydrate in 500 mL of deionized water, add 0.2 mol of citric acid, stir and mix at 200 rpm for 30 min, adjust the pH to 5.5 with 15% ammonia water, heat to 80℃, continue stirring and mixing for 100 min, cool to room temperature, homogenize three times at 150 MPa and 25℃, spray dry at an inlet temperature of 180℃ and an outlet temperature of 80℃, then transfer to a sintering furnace, heat to 300℃ at 5℃ / min, hold for 60 min, then switch to a mixture of oxygen and nitrogen with a volume ratio of 20:80 at a flow rate of 1.0 L / min, continue heating to 750℃, sinter for 3 h, cool to room temperature, and obtain particle A;

[0048] S2: Dissolve 0.1 mol of cerium nitrate hexahydrate, 0.005 mol of manganese nitrate tetrahydrate, and 0.005 mol of nickel nitrate hexahydrate in 500 mL of deionized water, add 0.11 mol of citric acid, stir and mix at 200 rpm for 30 min, adjust the pH to 5.5 with 15% ammonia water, heat to 80℃, continue stirring and mixing for 100 min, cool to room temperature, homogenize three times at 150 MPa and 25℃, spray dry at an inlet temperature of 180℃ and an outlet temperature of 80℃, then transfer to a sintering furnace, heat to 600℃ at 5℃ / min, hold for 3 h, cool to room temperature to obtain particles B;

[0049] S3: Mix 20g of particle A and 15g of particle B, place them in a ball mill, grind for 5 hours, add 0.53g of polyvinylpyrrolidone and 85g of deionized water, transfer to an ultrasonic device, power 500W, frequency 40KHz, treat for 30 minutes, add about 220g of magnesium-modified ceramic carrier, evacuate to -0.1MPa, vacuum impregnate for 50 minutes, remove surface residual liquid, dry at 80℃ for 3 hours, transfer to a sintering furnace, under a mixed gas of hydrogen and nitrogen with a volume ratio of 7:93, flow rate 0.5L / min, heat to 500℃ at 2℃ / min, hold for 130 minutes, cool to room temperature to obtain the deoxidizer.

[0050] The preparation method of magnesium-modified ceramsite carrier includes the following steps:

[0051] Add 210g of kaolin, 87.5g of corn starch, and 52.5g of magnesium-modified molecular sieve to a container, add 120mL of deionized water, knead until uniform, and extrude using a plum blossom-shaped through-hole mold (outer diameter 3mm / pore diameter 1mm). Cut into 5mm cylindrical sections, first dry at 80℃ for 2 hours, then raise the temperature to 100℃ and dry for 2 hours, continue to raise the temperature to 120℃ and dry for 2 hours, then transfer to a sintering furnace, raise the temperature to 550℃ at 5℃ / min, hold for 2 hours, switch to a nitrogen atmosphere, flow rate 1L / min. The temperature was increased to 1100℃ and held for 3 hours. After cooling to room temperature, the sample was immersed in a 0.15 mol / L nitric acid solution, heated to 100℃, and acid-washed for 2 hours. The sample was then filtered, washed with deionized water until neutral, and then immersed in a 0.6 mol / L magnesium nitrate solution. The sample was sonicated for 30 minutes at a power of 300 W and a frequency of 40 kHz. After filtration, the sample was dried at 100℃ for 2 hours and then transferred to a sintering furnace. The temperature was increased to 550℃ at a rate of 5℃ / min and sintered for 2 hours. After cooling to room temperature, the magnesium-modified ceramic particle carrier was obtained.

[0052] The preparation method of magnesium-modified molecular sieves includes the following steps:

[0053] 100g of SBA-15 molecular sieve was placed in a sintering furnace, heated to 550℃ at 5℃ / min, held for 4h, cooled to room temperature, immersed in 0.15mol / L nitric acid solution, heated to 100℃, acid washed for 3h, filtered, washed with deionized water until neutral, dried at 80℃ for 2h, immersed in 0.6mol / L magnesium nitrate solution, sonicated for 30min at 300W power and 20kHz frequency, filtered, rinsed twice with deionized water and once with anhydrous ethanol, dried at 100℃ for 2h, transferred to a sintering furnace, heated to 550℃ at 5℃ / min, held for 3h, cooled to room temperature, and magnesium-modified molecular sieve was obtained.

[0054] Example 2

[0055] The method for preparing the deoxidizer in this embodiment includes the following steps:

[0056] S1: Dissolve 0.1 mol of lanthanum nitrate hexahydrate, 0.05 mol of manganese nitrate tetrahydrate, and 0.05 mol of nickel nitrate hexahydrate in 500 mL of deionized water, add 0.3 mol of citric acid, stir and mix at 200 rpm for 30 min, adjust the pH to 6.0 with 15% ammonia water, heat to 75℃, continue stirring and mixing for 120 min, cool to room temperature, homogenize four times at 140 MPa and 20℃, spray dry at an inlet temperature of 180℃ and an outlet temperature of 80℃, then transfer to a sintering furnace, heat to 280℃ at 5℃ / min, hold for 70 min, then switch to a mixture of oxygen and nitrogen with a volume ratio of 15:85 at a flow rate of 1.0 L / min, continue heating to 720℃, sinter for 3.5 h, cool to room temperature, and obtain particle A;

[0057] S2: Dissolve 0.1 mol of cerium nitrate hexahydrate, 0.004 mol of manganese nitrate tetrahydrate, and 0.004 mol of nickel nitrate hexahydrate in 500 mL of deionized water, add 0.16 mol of citric acid, stir and mix at 200 rpm for 30 min, adjust the pH to 6.0 with 15% ammonia water, heat to 75℃, continue stirring and mixing for 120 min, cool to room temperature, homogenize four times at 140 MPa and 20℃, spray dry at an inlet temperature of 180℃ and an outlet temperature of 80℃, then transfer to a sintering furnace, heat to 580℃ at 5℃ / min, hold for 3.5 h, cool to room temperature to obtain particle B;

[0058] S3: Mix 15g of particle A and 15g of particle B, place them in a ball mill, grind for 4 hours, add 0.6g of polyvinylpyrrolidone and 70g of deionized water, transfer to an ultrasonic device, power 500W, frequency 40KHz, treat for 40 minutes, add about 150g of magnesium-modified ceramic carrier, evacuate to -0.1MPa, vacuum impregnate for 45 minutes, remove surface residual liquid, dry at 80℃ for 3 hours, transfer to a sintering furnace, under a mixed gas of hydrogen and nitrogen with a volume ratio of 5:95, flow rate 0.5L / min, heat to 480℃ at 2℃ / min, hold for 150 minutes, cool to room temperature to obtain the deoxidizer.

[0059] The preparation method of magnesium-modified ceramsite carrier includes the following steps:

[0060] Add 195g of kaolin, 75g of corn starch, and 30g of magnesium-modified molecular sieve to a container, add 105mL of deionized water, knead until uniform, and extrude using a plum blossom-shaped through-hole mold (outer diameter 3mm / pore diameter 1mm). Cut into 5mm cylindrical sections, first dry at 80℃ for 2 hours, then raise the temperature to 100℃ and dry for 2 hours, continue to raise the temperature to 120℃ and dry for 2 hours, then transfer to a sintering furnace, raise the temperature to 600℃ at 5℃ / min, hold for 1.5 hours, switch to a nitrogen atmosphere at a flow rate of 1L / min. The temperature was further increased to 1150℃ and held for 2.5 hours. After cooling to room temperature, the sample was immersed in a 0.2 mol / L nitric acid solution, heated to 80℃, and acid-washed for 2.5 hours. The sample was then filtered, washed with deionized water until neutral, and then immersed in a 0.8 mol / L magnesium nitrate solution. The sample was sonicated for 40 minutes at a power of 300 W and a frequency of 40 kHz. After filtration, the sample was dried at 100℃ for 2 hours and then transferred to a sintering furnace. The temperature was increased to 600℃ at a rate of 5℃ / min, and the sample was sintered for 1.5 hours. After cooling to room temperature, the magnesium-modified ceramic particle carrier was obtained.

[0061] The preparation method of magnesium-modified molecular sieves includes the following steps:

[0062] 100g of SBA-15 molecular sieve was placed in a sintering furnace, heated to 600℃ at 5℃ / min, held for 3.5h, cooled to room temperature, immersed in 0.2mol / L nitric acid solution, heated to 80℃, acid washed for 4h, filtered, washed with deionized water until neutral, dried at 80℃ for 2h, immersed in 0.8mol / L magnesium nitrate solution, sonicated for 40min at 300W power and 20kHz frequency, filtered, rinsed twice with deionized water and once with anhydrous ethanol, dried at 100℃ for 2h, transferred to a sintering furnace, heated to 600℃ at 5℃ / min, held for 2.5h, cooled to room temperature, and magnesium-modified molecular sieve was obtained.

[0063] Example 3

[0064] The method for preparing the deoxidizer in this embodiment includes the following steps:

[0065] S1: Dissolve 0.1 mol of lanthanum nitrate hexahydrate, 0.07 mol of manganese nitrate tetrahydrate, and 0.03 mol of nickel nitrate hexahydrate in 500 mL of deionized water, add 0.3 mol of citric acid, stir and mix at 200 rpm for 30 min, adjust the pH to 6.0 with 15% ammonia water, heat to 85℃, continue stirring and mixing for 90 min, cool to room temperature, homogenize three times at 160 MPa and 25℃, spray dry at an inlet temperature of 180℃ and an outlet temperature of 80℃, then transfer to a sintering furnace, heat to 320℃ at 5℃ / min, hold for 50 min, then switch to a mixture of oxygen and nitrogen with a volume ratio of 20:80 at a flow rate of 1.0 L / min, continue heating to 760℃, sinter for 3 h, cool to room temperature, and obtain particle A;

[0066] S2: Dissolve 0.1 mol of cerium nitrate hexahydrate, 0.006 mol of manganese nitrate tetrahydrate, and 0.004 mol of nickel nitrate hexahydrate in 500 mL of deionized water, add 0.16 mol of citric acid, stir and mix at 200 rpm for 30 min, adjust the pH to 6.0 with 15% ammonia water, heat to 85℃, continue stirring and mixing for 90 min, cool to room temperature, homogenize three times at 160 MPa and 25℃, spray dry at an inlet temperature of 180℃ and an outlet temperature of 80℃, then transfer to a sintering furnace, heat to 620℃ at 5℃ / min, hold for 3 h, cool to room temperature to obtain particles B;

[0067] S3: Mix 20g of particle A and 15g of particle B, place them in a ball mill, grind for 4 hours, add 0.88g of polyvinylpyrrolidone and 90g of deionized water, transfer to an ultrasonic device, power 500W, frequency 40KHz, treat for 35 minutes, add about 210g of magnesium-modified ceramic carrier, evacuate to -0.1MPa, vacuum impregnate for 55 minutes, remove surface residual liquid, dry at 80℃ for 3 hours, transfer to a sintering furnace, under a mixed gas of hydrogen and nitrogen with a volume ratio of 10:90, flow rate 0.5L / min, heat to 520℃ at 2℃ / min, hold for 110 minutes, cool to room temperature to obtain deoxidizer.

[0068] The preparation method of magnesium-modified ceramsite carrier includes the following steps:

[0069] Add 195g of kaolin, 75g of corn starch, 30g of magnesium-modified molecular sieve, and 9g of alumina fiber to a container, add 110mL of deionized water, knead until uniform, and extrude using a plum blossom-shaped through-hole mold (outer diameter 3mm / pore diameter 1mm). Cut into 5mm cylindrical sections, first dry at 80℃ for 2 hours, then raise the temperature to 100℃ and dry for 2 hours, continue to raise the temperature to 120℃ and dry for 2 hours, then transfer to a sintering furnace, raise the temperature to 600℃ at 5℃ / min, hold for 1.5 hours, switch to a nitrogen atmosphere at a flow rate of 1L. The temperature was increased to 1150℃ at a constant rate of 5℃ / min, held for 2.5h, cooled to room temperature, immersed in 0.2mol / L nitric acid solution, heated to 80℃, acid washed for 2.5h, filtered, washed with deionized water until neutral, and then immersed in 0.8mol / L magnesium nitrate solution. The mixture was sonicated for 40min at 300W and 40kHz, filtered, dried at 100℃ for 2h, transferred to a sintering furnace, heated to 600℃ at a constant rate of 5℃ / min, sintered for 1.5h, and cooled to room temperature to obtain magnesium-modified ceramic aggregate carrier.

[0070] The preparation method of magnesium-modified molecular sieves includes the following steps:

[0071] 100g of SBA-15 molecular sieve was placed in a sintering furnace, heated to 600℃ at 5℃ / min, held for 3.5h, cooled to room temperature, immersed in 0.2mol / L nitric acid solution, heated to 80℃, acid washed for 4h, filtered, washed with deionized water until neutral, dried at 80℃ for 2h, immersed in 0.8mol / L magnesium nitrate solution, sonicated for 40min at 300W power and 20kHz frequency, filtered, rinsed twice with deionized water and once with anhydrous ethanol, dried at 100℃ for 2h, transferred to a sintering furnace, heated to 600℃ at 5℃ / min, held for 2.5h, cooled to room temperature, and magnesium-modified molecular sieve was obtained.

[0072] Example 4

[0073] The difference between this embodiment and embodiment 3 is as follows:

[0074] In step S1, 0.1 mol of lanthanum nitrate hexahydrate, 0.05 mol of manganese nitrate tetrahydrate, 0.05 mol of nickel nitrate hexahydrate, and 0.01 mol of strontium nitrate were dissolved in 500 mL of deionized water. 0.3 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 6.0 using 15% ammonia water. The temperature was raised to 85 °C, and the mixture was stirred for another 90 min. The mixture was then cooled to room temperature and homogenized three times at 160 MPa and 25 °C. The mixture was then spray-dried at an inlet temperature of 180 °C and an outlet temperature of 80 °C. The mixture was then transferred to a sintering furnace, heated to 320 °C at a rate of 5 °C / min, and held for 50 min. A mixture of oxygen and nitrogen with a volume ratio of 20:80 and a flow rate of 1.0 L / min was then introduced, and the temperature was raised to 760 °C. The mixture was sintered for 3 h and then cooled to room temperature to obtain particles A.

[0075] The preparation method of magnesium-modified ceramsite carrier includes the following steps:

[0076] Add 195g of kaolin, 75g of corn starch, 30g of magnesium-modified molecular sieve, and 12g of alumina fiber to a container, add 110mL of deionized water, knead until uniform, and extrude using a plum blossom-shaped through-hole mold (outer diameter 3mm / pore diameter 1mm). Cut into 5mm cylinders, first dry at 80℃ for 2 hours, then heat to 100℃ and dry for 2 hours, then continue heating to 120℃ and dry for 2 hours. Then transfer to a sintering furnace, heat to 600℃ at 5℃ / min, hold for 1.5 hours, switch to nitrogen atmosphere, flow rate 1... The temperature was increased to 1150℃ at a constant rate of L / min, held for 2.5 h, cooled to room temperature, immersed in 0.2 mol / L nitric acid solution, heated to 80℃, acid washed for 2.5 h, filtered, washed with deionized water until neutral, and then immersed in 0.8 mol / L magnesium nitrate solution. The mixture was sonicated for 40 min at 300 W and 40 kHz, filtered, dried at 100℃ for 2 h, transferred to a sintering furnace, heated to 600℃ at a constant rate of 5℃ / min, sintered for 1.5 h, and cooled to room temperature to obtain magnesium-modified ceramic aggregate carrier.

[0077] Everything else is the same as in Example 3.

[0078] Example 5

[0079] The difference between this embodiment and embodiment 4 is that:

[0080] In step S3, after particle B, there is also a step of adding 1.05g of nano-strontium titanate.

[0081] Before use, nano-strontium titanate undergoes the following treatment steps:

[0082] Nano-sized strontium titanate and polyvinylpyrrolidone (PVP) were mixed at a mass ratio of 1:1, anhydrous ethanol was added, the solid-liquid ratio was 1:5, the mixture was ball-milled for 2 hours, dried at 60°C to constant weight, passed through a 300-mesh sieve, and the sieve-passed material was collected for later use.

[0083] The rest is the same as in Example 4.

[0084] Example 6

[0085] The difference between this embodiment and embodiment 5 is as follows:

[0086] In step S1, 0.1 mol of lanthanum nitrate hexahydrate, 0.05 mol of manganese nitrate tetrahydrate, 0.05 mol of nickel nitrate hexahydrate, and 0.02 mol of strontium nitrate were dissolved in 500 mL of deionized water. 0.3 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 6.0 using 15% ammonia water. The temperature was raised to 85 °C, and the mixture was stirred for another 90 min. The mixture was then cooled to room temperature and homogenized three times at 160 MPa and 25 °C. The mixture was then spray-dried at an inlet temperature of 180 °C and an outlet temperature of 80 °C. The mixture was then transferred to a sintering furnace, heated to 320 °C at a rate of 5 °C / min, and held for 50 min. A mixture of oxygen and nitrogen with a volume ratio of 20:80 and a flow rate of 1.0 L / min was then introduced, and the temperature was raised to 760 °C. The mixture was sintered for 3 h and then cooled to room temperature to obtain particles A.

[0087] In step S3, after particle B, there is also a step of adding 1.75g ​​of nano-strontium titanate.

[0088] Before use, nano-strontium titanate undergoes the following treatment steps:

[0089] Nano-sized strontium titanate and polyvinylpyrrolidone (PVP) were mixed at a mass ratio of 1:1.1, anhydrous ethanol was added, the solid-liquid ratio was 1:5, the mixture was ball-milled for 2 hours, dried at 60°C to constant weight, passed through a 300-mesh sieve, and the sieve-passed material was collected for later use.

[0090] The rest is the same as in Example 5.

[0091] Comparative Example 1

[0092] The preparation method of the deoxidizer in this comparative example includes the following steps:

[0093] S1: Dissolve 0.1 mol of lanthanum nitrate hexahydrate, 0.1 mol of cerium nitrate hexahydrate, 0.054 mol of manganese nitrate tetrahydrate, and 0.054 mol of nickel nitrate hexahydrate in 1000 mL of deionized water, add 0.46 mol of citric acid, stir and mix at 200 rpm for 30 min, adjust the pH to 6.0 with 15% ammonia water, heat to 75℃, continue stirring and mixing for 120 min, cool to room temperature, homogenize four times at 140 MPa and 20℃, spray dry at an inlet temperature of 180℃ and an outlet temperature of 80℃, then transfer to a sintering furnace, heat to 280℃ at 5℃ / min, hold for 70 min, then switch to a mixture of oxygen and nitrogen at a volume ratio of 15:85 at a flow rate of 1.0 L / min, continue heating to 720℃, sinter for 3.5 h, cool to room temperature, and obtain granules;

[0094] S2: Place 30g of particles in a ball mill and grind for 4 hours. Add 0.6g of polyvinylpyrrolidone and 70g of deionized water. Transfer to an ultrasonic device with a power of 500W and a frequency of 40KHz for 40 minutes. Add approximately 150g of magnesium-modified ceramic carrier. Vacuum the material to -0.1MPa and vacuum impregnate for 45 minutes. Remove residual liquid from the surface. Dry at 80℃ for 3 hours. Transfer to a sintering furnace. Heat to 480℃ at a flow rate of 0.5L / min under a mixed gas of hydrogen and nitrogen with a volume ratio of 5:95. Hold at this temperature for 150 minutes. Cool to room temperature to obtain the deoxidizer.

[0095] Everything else is the same as in Example 2.

[0096] Comparative Example 2

[0097] The difference between this comparative example and Example 1 is as follows:

[0098] The preparation method of ceramsite carrier includes the following steps:

[0099] Add 210g of kaolin, 87.5g of corn starch, and 52.5g of magnesium-modified molecular sieve to a container, add 120mL of deionized water, knead until uniform, and extrude using a plum blossom-shaped through-hole mold (outer diameter 3mm / pore diameter 1mm). Cut into 5mm cylinders, first dry at 80℃ for 2h, then heat to 100℃ and dry for 2h, then continue to heat to 120℃ and dry for 2h. Then transfer to a sintering furnace, heat to 550℃ at 5℃ / min and hold for 2h, switch to nitrogen atmosphere at a flow rate of 1L / min, continue to heat to 1100℃ and hold for 3h, cool to room temperature, immerse in 0.15mol / L nitric acid solution, heat to 100℃, acid wash for 2h, filter, wash with deionized water until neutral, and dry at 100℃ to constant weight to obtain ceramsite carrier.

[0100] Everything else is the same as in Example 1.

[0101] Comparative Example 3

[0102] The difference between this comparative example and Example 1 is as follows:

[0103] The preparation method of the deoxidizer in this comparative example includes the following steps:

[0104] S1: Dissolve 0.1 mol of lanthanum nitrate hexahydrate, 0.08 mol of manganese nitrate tetrahydrate, and 0.02 mol of nickel nitrate hexahydrate in 500 mL of deionized water, add 0.2 mol of citric acid, stir and mix at 200 rpm for 30 min, adjust the pH to 5.5 with 15% ammonia water, heat to 80℃, continue stirring and mixing for 100 min, cool to room temperature, homogenize three times at 150 MPa and 25℃, spray dry at an inlet temperature of 180℃ and an outlet temperature of 80℃, then transfer to a sintering furnace, heat to 300℃ at 5℃ / min, hold for 60 min, then switch to a mixture of oxygen and nitrogen at a volume ratio of 20:80 at a flow rate of 1.0 L / min, continue heating to 750℃, sinter for 3 h, cool to room temperature, and obtain granules;

[0105] S3: Place 20g of particles in a ball mill and grind for 5 hours. Add 0.4g of polyvinylpyrrolidone and 45g of deionized water. Transfer to an ultrasonic device with a power of 500W and a frequency of 40KHz for 30 minutes. Add approximately 120g of magnesium-modified ceramic carrier. Vacuum the material to -0.1MPa and vacuum impregnate for 50 minutes. Remove residual liquid from the surface. Dry at 80℃ for 3 hours. Transfer to a sintering furnace and heat to 500℃ at a flow rate of 0.5L / min under a mixed gas of hydrogen and nitrogen with a volume ratio of 7:93. Hold at this temperature for 130 minutes and cool to room temperature to obtain the deoxidizer.

[0106] Everything else is the same as in Example 1.

[0107] Performance testing

[0108] The deoxidizers prepared in Examples 1-6 and Comparative Examples 1-3 were respectively loaded into a fixed-bed reactor (50g loading amount). The operating temperature was set to 25±5℃, the pressure to 5MPa, and propylene gas with an oxygen content of 100ppm was introduced. The space velocity was set to 1000h. -1The oxygen concentration of the outlet gas was monitored using an online laser oxygen analyzer. When the outlet oxygen concentration was ≤0.1ppm, it was considered qualified. The gas was continuously circulated until the outlet oxygen concentration was ≥0.1ppm, at which point the test was stopped, and the cumulative oxygen volume adsorbed by the deoxidizer was recorded. The deoxidation capacity (unit: mL / g) was calculated. After each failure, the deoxidizer was regenerated for 2 hours in a mixed atmosphere of H2 and N2 (volume ratio of 10:90) at 500℃. After the activity was restored, the above deoxidation test was repeated. After 50 cycles, the capacity retention rate (capacity after cycle / initial capacity × 100%) was calculated. Five molded deoxidizer particles were randomly selected, the surface dust was cleaned with anhydrous ethanol, dried at 60℃, and the maximum pressure when a single particle broke was measured. The average value was taken and is shown in Table 1.

[0109] Table 1. Performance test data of the deoxidizers prepared in Examples 1-6 and Comparative Examples 1-3

[0110]

[0111] A comparison of performance data from Examples 1-3 and Comparative Examples 1-3 shows that the stepwise synthesis process of this application is key to improving deoxidation performance. Examples 1-3, through a stepwise synthesis process, constructed a multiphase composite system consisting of a perovskite-like phase (auxiliary phase: metallic Ni phase), fluorite CeO2 phase, and a magnesium-modified support. Crucially, this process effectively isolates different precursors, ensuring the independent formation and coexistence of key functional phases (especially the highly efficient oxygen storage phase CeO2). A synergistic interface is formed between the multiphases (especially the perovskite-like phase / fluorite CeO2 interface), achieving functional coupling and kinetic acceleration of oxygen storage, oxygen transfer, and oxygen consumption. This is the core mechanism that significantly improves deoxidation capacity. In contrast, the one-step process of Comparative Example 1, due to Ce... 4+ Due to poor compatibility with the perovskite structure, a phase-separated mixture of defective perovskite and CeO2 is actually formed. Subsequent reduction treatment further induces nickel ion precipitation into the metallic nickel phase, resulting in a deoxidation capacity far lower than that of the multiphase system synthesized stepwise. Meanwhile, the sintering optimization of alumina fiber reinforcement and magnesium-modified support significantly improves the mechanical strength and structural stability of the deoxidizer, providing solid physical support for the material to maintain high activity during long-term cycling.

[0112] From Example 4 via Sr 2+ Doping with La sites induces lattice oxygen vacancies by utilizing the charge imbalance effect, thereby improving oxygen ion mobility. In Examples 5 and 6, nano-strontium titanate is introduced, which forms a coherent interface with the main perovskite phase. The lattice distortion at the interface reduces the oxygen migration energy barrier, thereby accelerating deoxygenation kinetics and improving cycle stability.

[0113] Combination Figure 1As can be seen, Example 2, through a distributed synthesis process, forms a pure La(Mn,Ni)O3 perovskite-like phase in step S1, exhibiting characteristic peaks at 32.5°, 40°, and 46°. In step S2, a Mn,Ni-doped CeO2 fluorite phase is formed, corresponding to characteristic peaks at 28.5°, 47.5°, and 56.3°. The magnesium modification process introduces the MgO phase, corresponding to a characteristic peak at 42.9°. The reduction treatment does not destroy the main crystal lattice and does not produce characteristic peaks of metallic nickel. The characteristic peak at 30.5° indicates that lattice strain and electronic interaction occur at the interface between the two active phases, forming oxygen vacancy migration channels. The coexistence of multiphase characteristic peaks (perovskite, fluorite, and support) and interface peaks, precisely separated by XRD, confirms that the stepwise synthesis process successfully constructs a multiphase synergistic structure. Nickel / manganese ions are stably dissolved in the crystal lattice, and the reduction only optimizes the surface valence state and oxygen defects.

[0114] Combination Figure 2 It can be seen that Comparative Example 1 uses a one-pot co-precipitation method to synthesize a single (La,Ce)(Mn,Ni)O3 solid solution, but because Ce... 4+ Incompatible with the perovskite structure, sintering actually produced defective perovskite phases (33°, 40.3°) and independent CeO2 phases (28.5°, 47.5°). Subsequent reduction treatment caused nickel ions to detach from the unstable lattice, precipitating metallic nickel (characteristic peak at 43.2°), while the support contributed a MgO peak (42.9°). The 47.3° peak in XRD is a superposition peak of CeO2 and perovskite, and the interface coupling peak (30.5°) is missing. This indicates that the co-precipitation process induced cerium phase separation, the reduction step destroyed the perovskite structure, and the final product was a multiphase mixture, which contradicted the target solid solution design.

[0115] 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 method for preparing a deoxidizer, characterized in that, Includes the following steps: S1: Dissolve lanthanum salt, manganese salt and nickel salt in water with a molar ratio of 1:x:(1-x), add citric acid to adjust the pH to 5.5~6.0, heat to 75~85℃, mix for 90~120min, spray dry, first at 280~320℃ for 50~70min, switch to a mixture of O2 and N2, sinter at 720~760℃ for 3~3.5h to obtain granules A; S2: Dissolve cerium salt, manganese salt and nickel salt in water with a molar ratio of 1:(0.04~0.06):(0.04~0.05), add citric acid to adjust the pH to 5.5~6.0, heat to 75~85℃, mix for 90~120min, spray dry, and sinter at 580~620℃ for 3~3.5h to obtain particles B; S3: Mix particles A and B, grind for 4-5 hours, add dispersant and water, mix evenly, add magnesium-modified ceramic carrier, vacuum impregnate for 45-55 minutes, separate solid and liquid, dry, and keep warm at 480-520℃ for 110-150 minutes under a mixture of H2 and N2, then cool to obtain deoxidizer. In step S1, the value of x is in the range of 0.5 to 0.8; in the mixture of O2 and N2, the volume ratio of O2 to N2 is (15~20):(80~85). The preparation method of the magnesium-modified ceramsite carrier includes the following steps: Kaolin, pore-forming agent, and magnesium-modified molecular sieve are added to a reactor, kneaded with water until homogeneous, extruded, granulated, and dried. The mixture is then sintered at 550–600℃ for 1.5–2 hours, followed by switching to an inert atmosphere and further heating to 1100–1150℃ for 2.5–3 hours. After cooling, the mixture is immersed in nitric acid with a molar concentration of 0.15–0.2 mol / L, heated to 80–100℃, and acid-washed for 2–2.5 hours. Solid-liquid separation is achieved, followed by washing until neutral. The mixture is then immersed in magnesium nitrate solution with a molar concentration of 0.6–0.8 mol / L and sonicated for 30–40 minutes. Solid-liquid separation is achieved again, followed by washing, drying, and sintering at 550–600℃ for 1.5–2 hours. After cooling, the final product is obtained.

2. The method for preparing the deoxidizer according to claim 1, characterized in that, In step S3, the mass ratio of particle A to particle B is (3~4):

3.

3. The method for preparing the deoxidizer according to claim 1, characterized in that, In step S3, the volume ratio of H2 to N2 in the H2 and N2 mixture is (5~10):(90~95).

4. The method for preparing the deoxidizer according to claim 1, characterized in that, The mass ratio of the kaolin, pore-forming agent and magnesium-modified molecular sieve is (6~6.5):2.5:(1~1.5).

5. The method for preparing the deoxidizer according to claim 1, characterized in that, The preparation method of the magnesium-modified molecular sieve includes the following steps: SBA-15 molecular sieve was placed in a sintering furnace, heated to 550-600℃, held for 3.5-4 hours, cooled to room temperature, immersed in nitric acid with a molar concentration of 0.15-0.2 mol / L, heated to 80-100℃, acid washed for 3-4 hours, solid-liquid separation, washed until neutral, immersed in magnesium nitrate solution with a molar concentration of 0.6-0.8 mol / L, sonicated for 30-40 minutes, solid-liquid separation, washed, dried, sintered at 550-600℃ for 2.5-3 hours, cooled, and magnesium-modified molecular sieve was obtained.

6. The method for preparing the deoxidizer according to claim 1, characterized in that, The preparation method of the magnesium-modified ceramsite carrier includes a step of adding alumina fibers after the magnesium-modified molecular sieve. The amount of alumina fibers is 3% to 4% of the total mass of kaolin, pore-forming agent and magnesium-modified molecular sieve.

7. The method for preparing the deoxidizer according to claim 1, characterized in that, In step S1, after the nickel salt, a step of adding strontium salt is also included, wherein the molar ratio of lanthanum salt to strontium salt is 1:(0.1~0.2).

8. A deoxidizer prepared by the method of any one of claims 1 to 7.

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