A multi-stage composite metal oxide deoxidizer and its application

Abstract

The present invention relates to the field of petrochemical technology, and more specifically to a multi-stage composite metal oxide deoxidizer and its application. The deoxidizer uses two or more of alumina, 13X, and NaY as supports and incorporates six active components: K2O, MgO, CaO, Fe2O3, TiO2, and ZnO. It is used to remove oxygenated compounds such as methanol, dimethyl ether, MTBE, and carbon dioxide from light hydrocarbons. It exhibits a high removal depth (≤1 ppm), a large adsorption capacity (≥13% per unit weight), high thermal stability, and reusability after regeneration. The present invention also discloses a method for preparing the multi-stage composite deoxidizer and its application in deoxygenation of mixed C4.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical industry, in particular to a multi-stage composite metal oxide deoxidizer and application thereof. Background Art

[0002] As my country's crude oil processing capacity increases, refineries' catalytic cracking, hydrocracking, and delayed coking units will produce large quantities of liquefied petroleum gas (LPG), containing approximately 30-50% light hydrocarbons. If burned as fuel, their value is very low. The comprehensive utilization of light hydrocarbons has become a major research area for petrochemical companies and research institutions. Isobutylene is the most abundant and valuable component of C4 hydrocarbons. The reaction of isobutylene with methanol to synthesize MTBE is a widely used method for separating isobutylene and 1-butene for comprehensive C4 utilization. However, the isobutylene feedstock produced by MTBE cracking contains trace amounts of oxygenates such as dimethyl ether, methanol, and MTBE. Polymerization catalysts used in polyisobutylene production have very strict requirements for the oxygenate impurity content of the isobutylene feedstock. These trace oxygenate impurities can damage the catalyst's active sites or react with its active components, reducing its activity and selectivity, severely impacting product quality and yield. The removal of unreacted methanol and small oxygenates such as dimethyl ether (DME) produced as a side effect from the etherification reaction's tail gas is a key factor restricting its comprehensive utilization. Furthermore, with the rapid development of my country's coal chemical industry, plants for producing olefins, aromatics, and synthetic oils using methanol as a base feedstock have become widespread. The need to incorporate efficient oxygenate separation technologies into these processes is also a pressing issue.

[0003] Currently, the removal of oxygenated compounds from mixed C4 hydrocarbons is mainly based on distillation. However, this method has disadvantages such as large material circulation, bulky equipment, high energy consumption, and difficulty in controlling separation accuracy. Therefore, it is necessary to seek a technology for removing oxygenated compounds with low energy consumption, high removal accuracy, low cost, no environmental pollution, and easy industrialization. In recent years, the adsorption method has been highly valued by refining and chemical companies due to its advantages such as low energy consumption, low investment, simple process, and easy operation. It is a new process for removing oxygenated compounds with broad application prospects. The development of adsorbents with high adsorption capacity, strong selectivity, few side reactions, and easy regeneration for efficient removal of oxygenated compounds is the key to this technology. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-stage composite metal oxide deoxidizer and its application to solve the problems of low adsorption capacity, low selectivity and few regeneration times of existing light hydrocarbon deoxidizers.

[0005] To achieve the above objectives, this application is implemented through the following technical solutions:

[0006] A multi-stage composite metal oxide deoxidizer comprises a support and active components, wherein the support is a mixture of two or more of alumina, 13X and NaY, and the active components are K2O, MgO, CaO, Fe2O3, TiO2 and ZnO.

[0007] The content of the active component oxide in the deoxidizer accounts for 3-30% of the total mass fraction of the deoxidizer, preferably 8-14%.

[0008] When the support contains aluminum oxide, the effect is better if its mass content is less than 60% of the total amount of the support.

[0009] The active component K2O in the deoxidizer accounts for 1-5% of the total mass fraction of the deoxidizer, preferably 1-3%.

[0010] The active component CaO in the deoxidizer accounts for 1-5% of the total mass fraction of the deoxidizer, preferably 1-3%.

[0011] The active component Fe2O3 in the deoxidizer accounts for 1-5% of the total mass fraction of the deoxidizer, preferably 1-3%.

[0012] The active component TiO2 in the deoxidizer accounts for 1-5% of the total mass fraction of the deoxidizer, preferably 1-3%.

[0013] The active component ZnO in the deoxidizer accounts for 1-5% of the total mass fraction of the deoxidizer, preferably 1-3%.

[0014] Furthermore, the preparation method of the multi-stage composite metal oxide deoxidizer comprises the following steps:

[0015] (1) Mixing the support and the active component precursor uniformly;

[0016] (2) adding nitric acid, citric acid, and carboxymethyl cellulose to deionized water, stirring and dissolving the mixture, and then pouring it into the mixture obtained in step (1), and continuing to mix evenly;

[0017] (3) Extruding the mixture obtained in step (2) multiple times, mixing evenly and then forming strips;

[0018] (4) Drying and calcining the product obtained in step (3) to obtain the desired deoxidizer.

[0019] Preferably, in step (2), the mass of the added nitric acid accounts for 3-6% of the mass of the support, the mass of the added citric acid accounts for 2-5% of the mass of the support, and the mass of the added carboxymethyl cellulose accounts for 2-5% of the mass of the support.

[0020] Furthermore, the drying and calcining in step (3) are specifically as follows: drying at 60°C for 3 hours, drying at 120°C for 6 hours, and finally calcining at 500°C for 5 hours.

[0021] Preferably, the precursor of the active component K in the present invention is selected from potassium carbonate and potassium oxide.

[0022] Preferably, the precursor of the active component Mg in the present invention is selected from magnesium hydroxide and magnesium oxide.

[0023] Preferably, the precursor of the active component Ca in the present invention is selected from calcium hydroxide and calcium oxide.

[0024] Preferably, the precursor of the active component Fe in the present invention is iron oxide.

[0025] Preferably, the precursor of the active component Ti in the present invention is metatitanic acid.

[0026] Preferably, the precursor of the active component Zn in the present invention is zinc oxide.

[0027] In the present invention, multiple metal active components are added, and the synergistic effect between metal oxides is utilized to increase the catalyst's adsorption of oxygen-containing compounds in light hydrocarbons; at the same time, through kneading and roasting, the metal components are easily cross-linked, which helps to improve the thermal stability of the catalyst and facilitates multiple regeneration applications of the catalyst.

[0028] In the present invention, a multi-stage composite metal oxide deoxidizer is used. The multi-stage composite metal oxide deoxidizer needs to be treated as follows before use:

[0029] (1) First, cut the deoxidizer into strips of 4-8 mm in length;

[0030] (2) The deoxidizer was loaded into a fixed bed reactor, heated to 300°C under a nitrogen atmosphere and dried for 6 h, and then purged and cooled;

[0031] (3) After the temperature drops to room temperature, the system pressure is raised to 0.5 MPa using nitrogen. Subsequently, the C4 raw material mixed with oxygen-containing compounds is injected into the reactor. The product results are analyzed using gas chromatography to calculate the adsorption capacity of the deoxidizer.

[0032] (4) After the deoxidizer is saturated with adsorption, it is purged with nitrogen and then heated to 300°C for regeneration. When the content of oxygen-containing compounds in the tail gas is less than 1 ppm, the regeneration is stopped. After the temperature drops to room temperature, the pressure is resumed and the deoxidation evaluation experiment is continued.

[0033] The deoxidizer of the present invention has the following excellent properties: (1) multiple metal oxides act synergistically to increase adsorption capacity; (2) it has high thermal stability and can be regenerated multiple times, thereby reducing production costs; and (3) it has a simple preparation process and is convenient for mass production and industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is the XRD spectrum of the deoxidizer in Example 3;

[0035] Figure 2 This is the nitrogen adsorption-desorption isotherm spectrum of the deoxidizer in Example 3. DETAILED DESCRIPTION

[0036] The technical solutions of the present invention are described in detail below through examples. The following examples are merely exemplary and can only be used to explain and illustrate the technical solutions of the present invention, and cannot be interpreted as limiting the technical solutions of the present invention.

[0037] The present application provides a method for preparing a deoxidizer that is simple to operate, has high adsorption capacity, high thermal stability, and can be regenerated multiple times, thereby solving the problems of low adsorption capacity and rapid decrease in adsorption capacity after regeneration. The prepared multi-metal composite deoxidizer has high adsorption capacity and good stability in the mixed C4 deoxygenation reaction.

[0038] In the preparation of the catalyst of the present application, a variety of metal oxides are introduced, one of which is to utilize the synergistic effect between metals to increase the adsorption capacity, and the other is to improve the thermal stability during the calcination process.

[0039] The deoxidizer prepared in this application is loaded into a fixed-bed continuous reactor, using mixed C4 containing oxides such as methanol, dimethyl ether, and MTBE as raw material, and the oxide content of the product is tested after adsorption deoxidation.

[0040] Example 1

[0041] (1) 120 g of 13X molecular sieve, 16 g of aluminum hydroxide gel, 3.2 g of potassium carbonate, 1.4 g of calcium hydroxide, 1.6 g of magnesium hydroxide, 2.16 g of iron oxide, 1.3 g of metatitanic acid, and 1.08 g of zinc oxide were mixed uniformly;

[0042] (2) Add 6 g of concentrated nitric acid, 3 g of citric acid, and 3 g of carboxymethyl cellulose to 80 g of deionized water, stir to dissolve, and then pour into the mixture obtained in step (1), and continue stirring;

[0043] (3) The mixture obtained in step (2) is poured into an extruder and extruded and stirred for multiple times, then loaded into a mold for extrusion molding, dried at 60°C for 3 hours, dried at 120°C for 6 hours, and finally calcined at 500°C for 5 hours to obtain a multi-stage composite oxide deoxidizer with 13X molecular sieve and alumina as supports (the mass of alumina accounts for 10% of the total amount of the support) and 2% K2O, 1% CaO, 1% MgO, 2% Fe2O3, 1% TiO2, and 1% ZnO as active components.

[0044] (4) The prepared deoxidizer was cut into pieces of 4-8 mm in length and loaded into a fixed bed reactor. The temperature was raised to 300°C under a nitrogen atmosphere and dried for 6 h. The temperature was then purged and cooled. After the temperature dropped to room temperature, the system pressure was raised to 0.5 MPa using nitrogen. Subsequently, the C4 raw material mixed with oxygen-containing compounds was injected into the reactor. The product results were analyzed by gas chromatography to calculate the adsorption capacity of the deoxidizer.

[0045] (5) After the deoxidizer is saturated with adsorption, it is purged with nitrogen and then heated to 300°C for regeneration. When the content of oxygen-containing compounds in the tail gas is less than 1 ppm, the regeneration is stopped. After the temperature drops to room temperature, the pressure is resumed and the deoxidation evaluation experiment is continued. The changes in adsorption capacity after three regenerations are compared.

[0046] Example 2

[0047] (1) 112 g of 13X molecular sieve, 15 g of aluminum hydroxide gel, 4.8 g of potassium carbonate, 2.8 g of calcium hydroxide, 3.2 g of magnesium hydroxide, 3.24 g of iron oxide, 2.6 g of metatitanic acid, and 2.16 g of zinc oxide were mixed uniformly;

[0048] (2) Dissolve 6 g of concentrated nitric acid, 3 g of citric acid, and 3 g of carboxymethyl cellulose in 78 g of deionized water, stir well, and then pour into the mixture obtained in step (1), and continue stirring;

[0049] (3) The mixture obtained in step (2) is poured into an extruder and extruded and stirred for multiple times, then loaded into a mold for extrusion molding, dried at 60°C for 3 hours, dried at 120°C for 6 hours, and finally calcined at 500°C for 5 hours to obtain a multi-stage composite oxide deoxidizer with 13X molecular sieve and alumina as supports (the mass of alumina accounts for 10% of the total amount of the support) and 3% K2O, 2% CaO, 2% MgO, 3% Fe2O3, 2% TiO2, and 2% ZnO as active components.

[0050] (4) The prepared deoxidizer was cut into pieces of 4-8 mm in length and loaded into a fixed bed reactor. The temperature was raised to 300°C under a nitrogen atmosphere and dried for 6 h. The temperature was then purged and cooled. After the temperature dropped to room temperature, the system pressure was raised to 0.5 MPa using nitrogen. Subsequently, the C4 raw material mixed with oxygen-containing compounds was injected into the reactor. The product results were analyzed by gas chromatography to calculate the adsorption capacity of the deoxidizer.

[0051] (5) After the deoxidizer is saturated with adsorption, it is purged with nitrogen and then heated to 300°C for regeneration. When the content of oxygen-containing compounds in the tail gas is less than 1 ppm, the regeneration is stopped. After the temperature drops to room temperature, the pressure is resumed and the deoxidation evaluation experiment is continued. The changes in adsorption capacity after three regenerations are compared.

[0052] Example 3

[0053] (1) 112 g of 13X molecular sieve, 16 g of aluminum hydroxide gel, 3.2 g of potassium carbonate, 2.8 g of calcium hydroxide, 3.2 g of magnesium hydroxide, 2.16 g of iron oxide, 1.3 g of metatitanic acid, and 1.08 g of zinc oxide were mixed uniformly;

[0054] (2) Dissolve 6 g of concentrated nitric acid, 3 g of citric acid, and 3 g of carboxymethyl cellulose in 80 g of deionized water, stir evenly, and then pour into the mixture obtained in step (1), and continue stirring;

[0055] (3) The mixture obtained in step (2) is poured into an extruder and extruded and stirred for multiple times, then loaded into a mold for extrusion molding, dried at 60°C for 3 hours, dried at 120°C for 6 hours, and finally calcined at 500°C for 5 hours to obtain a multi-stage composite oxide deoxidizer with 13X molecular sieve and alumina as supports (the mass of alumina accounts for 10% of the total amount of the support) and 2% K2O, 1% CaO, 2% MgO, 2% Fe2O3, 1% TiO2, and 2% ZnO as active components.

[0056] (4) The prepared deoxidizer was cut into pieces of 4-8 mm in length and loaded into a fixed bed reactor. The temperature was raised to 300°C under a nitrogen atmosphere and dried for 6 h. The temperature was then purged and cooled. After the temperature dropped to room temperature, the system pressure was raised to 0.5 MPa using nitrogen. Subsequently, the C4 raw material mixed with oxygen-containing compounds was injected into the reactor. The product results were analyzed by gas chromatography to calculate the adsorption capacity of the deoxidizer.

[0057] (5) After the deoxidizer is saturated with adsorption, it is purged with nitrogen and then heated to 300°C for regeneration. When the content of oxygen-containing compounds in the tail gas is less than 1 ppm, the regeneration is stopped. After the temperature drops to room temperature, the pressure is resumed and the deoxidation evaluation experiment is continued. The changes in adsorption capacity after three regenerations are compared.

[0058] Example 4

[0059] (1) 120 g of NaY molecular sieve, 16 g of aluminum hydroxide gel, 3.2 g of potassium carbonate, 1.4 g of calcium hydroxide, 1.6 g of magnesium hydroxide, 2.16 g of iron oxide, 1.3 g of metatitanic acid, and 1.08 g of zinc oxide were mixed uniformly;

[0060] (2) Dissolve 6 g of concentrated nitric acid, 3 g of citric acid, and 3 g of carboxymethyl cellulose in 80 g of deionized water, stir to dissolve, and then pour into the mixture obtained in step (1), and continue stirring;

[0061] (3) The mixture obtained in step (2) is poured into an extruder and extruded and stirred for multiple times, then loaded into a mold for extrusion molding, dried at 60°C for 3 hours, dried at 120°C for 6 hours, and finally calcined at 500°C for 5 hours to obtain a multi-stage composite oxide deoxidizer with NaY molecular sieve and alumina as supports (the mass of alumina accounts for 10% of the total amount of the support) and 2% K2O, 1% CaO, 1% MgO, 2% Fe2O3, 1% TiO2, and 1% ZnO as active components.

[0062] (4) The prepared deoxidizer was cut into pieces of 4-8 mm in length and loaded into a fixed bed reactor. The temperature was raised to 300°C under a nitrogen atmosphere and dried for 6 h. The temperature was then purged and cooled. After the temperature dropped to room temperature, the system pressure was raised to 0.5 MPa using nitrogen. Subsequently, the C4 raw material mixed with oxygen-containing compounds was injected into the reactor. The product results were analyzed by gas chromatography to calculate the adsorption capacity of the deoxidizer.

[0063] (5) After the deoxidizer is saturated with adsorption, it is purged with nitrogen and then heated to 300°C for regeneration. When the content of oxygen-containing compounds in the tail gas is less than 1 ppm, the regeneration is stopped. After the temperature drops to room temperature, the pressure is resumed and the deoxidation evaluation experiment is continued. The changes in adsorption capacity after three regenerations are compared.

[0064] Comparative Example 1

[0065] (1) 67 g of NaY molecular sieve, 80 g of aluminum hydroxide gel, 3.2 g of potassium carbonate, 1.4 g of calcium hydroxide, 1.6 g of magnesium hydroxide, 2.16 g of iron oxide, 1.3 g of metatitanic acid, and 1.08 g of zinc oxide were mixed uniformly;

[0066] (2) Dissolve 6 g of concentrated nitric acid, 3 g of citric acid, and 3 g of carboxymethyl cellulose in deionized water, stir to dissolve, and then pour into the mixture obtained in step (1), and continue stirring;

[0067] (3) The mixture obtained in step (2) is poured into an extruder and extruded and stirred for multiple times, then loaded into a mold for extrusion molding, dried at 60°C for 3 hours, dried at 120°C for 6 hours, and finally calcined at 500°C for 5 hours to obtain a multi-stage composite oxide deoxidizer with NaY molecular sieve and alumina as supports (the mass of alumina accounts for 80% of the total amount of the support) and 2% K2O, 1% CaO calcium oxide, 1% MgO magnesium oxide, 2% Fe2O3 iron oxide, 1% TiO2, and 1% ZnO as active components.

[0068] (4) The prepared deoxidizer was cut into pieces of 4-8 mm in length and loaded into a fixed bed reactor. The temperature was raised to 300°C under a nitrogen atmosphere and dried for 6 h. The temperature was then purged and cooled. After the temperature dropped to room temperature, the system pressure was raised to 0.5 MPa using nitrogen. Subsequently, the C4 raw material mixed with oxygen-containing compounds was injected into the reactor. The product results were analyzed by gas chromatography to calculate the adsorption capacity of the deoxidizer.

[0069] (5) After the deoxidizer is saturated with adsorption, it is purged with nitrogen and then heated to 300°C for regeneration. When the content of oxygen-containing compounds in the tail gas is less than 1 ppm, the regeneration is stopped. After the temperature drops to room temperature, the pressure is resumed and the deoxidation evaluation experiment is continued. The changes in adsorption capacity after three regenerations are compared.

[0070] Comparative Example 2

[0071] (1) Mix 112 g of 13X molecular sieve, 16 g of aluminum hydroxide gel, 0 g of potassium oxide, 2.16 g of calcium oxide, 1.08 g of magnesium oxide, 1.08 g of iron oxide, 1.3 g of metatitanic acid, and 1.08 g of zinc oxide;

[0072] (2) Dissolve 6 g of concentrated nitric acid, 3 g of citric acid, and 3 g of carboxymethyl cellulose in 80 g of deionized water, stir evenly, and then pour into the mixture obtained in step (1), and continue stirring;

[0073] (3) The mixture obtained in step (2) is poured into an extruder and extruded and stirred for multiple times, then loaded into a mold for extrusion molding, dried at 60°C for 3 hours, dried at 120°C for 6 hours, and finally calcined at 500°C for 5 hours to obtain a multi-stage composite oxide deoxidizer with 13X molecular sieve, NaY molecular sieve and alumina as supports (the mass of alumina accounts for 10% of the total amount of the support) and 0% K2O, 2% CaO, 1% MgO, 1% Fe2O3, 1% TiO2, and 1% ZnO as active components.

[0074] (4) The prepared deoxidizer was cut into pieces of 4-8 mm in length and loaded into a fixed bed reactor. The temperature was raised to 300°C under a nitrogen atmosphere and dried for 6 h. The temperature was then purged and cooled. After the temperature dropped to room temperature, the system pressure was raised to 0.5 MPa using nitrogen. Subsequently, the C4 raw material mixed with oxygen-containing compounds was injected into the reactor. The product results were analyzed by gas chromatography to calculate the adsorption capacity of the deoxidizer.

[0075] (5) After the deoxidizer is saturated with adsorption, it is purged with nitrogen and then heated to 300°C for regeneration. When the content of oxygen-containing compounds in the tail gas is less than 1 ppm, the regeneration is stopped. After the temperature drops to room temperature, the pressure is resumed and the deoxidation evaluation experiment is continued. The changes in adsorption capacity after three regenerations are compared.

[0076] Comparative Example 3

[0077] (1) 112 g of 13X molecular sieve, 16 g of aluminum hydroxide gel, 6.4 g of potassium carbonate, 1.4 g of calcium hydroxide, 1.6 g of magnesium hydroxide, 2.16 g of iron oxide, 1.3 g of metatitanic acid, and 1.08 g of zinc oxide were mixed uniformly;

[0078] (2) Dissolve 6 g of concentrated nitric acid, 3 g of citric acid, and 3 g of carboxymethyl cellulose in deionized water, stir to dissolve, and then pour into the mixture obtained in step (1), and continue stirring;

[0079] (3) The mixture obtained in step (2) is poured into an extruder and extruded and stirred for multiple times, then loaded into a mold for extrusion molding, dried at 60°C for 3 hours, dried at 120°C for 6 hours, and then calcined at 500°C for 5 hours to obtain a multi-stage composite oxide deoxidizer with NaY molecular sieve and alumina as supports (the mass of alumina accounts for 10% of the total amount of the support) and 4% K2O, 3% CaO calcium oxide, 3% MgO magnesium oxide, 3% Fe2O3 iron oxide, 4% TiO2, and 3% ZnO as active components.

[0080] (4) The prepared deoxidizer was cut into pieces of 4-8 mm in length and loaded into a fixed bed reactor. The temperature was raised to 300°C under a nitrogen atmosphere and dried for 6 h. The temperature was then purged and cooled. After the temperature dropped to room temperature, the system pressure was raised to 0.5 MPa using nitrogen. Subsequently, the C4 raw material mixed with oxygen-containing compounds was injected into the reactor. The product results were analyzed by gas chromatography to calculate the adsorption capacity of the deoxidizer.

[0081] (5) After the deoxidizer is saturated with adsorption, it is purged with nitrogen and then heated to 300°C for regeneration. When the content of oxygen-containing compounds in the tail gas is less than 1 ppm, the regeneration is stopped. After the temperature drops to room temperature, the pressure is resumed and the deoxidation evaluation experiment is continued. The changes in adsorption capacity after three regenerations are compared.

[0082] Table 1 summarizes the adsorption capacity results of different adsorbents after reaction. The adsorption capacity is based on the mass of the deoxidizer, and the adsorbed oxides are the mass percentage of the catalyst.

[0083] Table 1

[0084]

[0085] Comparison of the data in Table 1 shows that the adsorbents prepared using the kneading method exhibit high activity and excellent stability in the process of mixing C4 deoxygenated compounds. Compared with the technical solution of the present application, Comparative Example 1, which increases the alumina content in the deoxidizer, results in a decrease in adsorption capacity; Comparative Example 2, which reduces the active component content, significantly reduces both the adsorption capacity and stability of the resulting deoxidizer; and Comparative Example 3, which increases the active component metal oxide content in the deoxidizer, results in a decrease in adsorption capacity and significantly reduced stability.

[0086] The above description is merely an embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, it is not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An application method of a multi-stage composite metal oxide deoxidizer, characterized in that: Perform the following processing: (1) First, cut the deoxidizer into strips of 4-8 mm in length; (2) The deoxidizer was loaded into a fixed bed reactor, heated to 300 °C under a nitrogen atmosphere and dried for 6 h, then purged and cooled; (3) After the temperature drops to room temperature, the system pressure is raised to 0.5 MPa using nitrogen. Subsequently, the C4 raw material mixed with oxygen-containing compounds is injected into the reactor, and the product results are analyzed by gas chromatography; (4) After the deoxidizer is saturated with adsorption, it is purged with nitrogen and then heated to 300°C for regeneration. When the content of oxygenated compounds in the tail gas is less than 1 ppm, regeneration is stopped. After the temperature drops to room temperature, the pressure is resumed and the deoxidation is continued. The multi-stage composite metal oxide deoxidizer comprises a support and an active component, wherein the support is a mixture of two or more of alumina, 13X, and NaY, and the active component is K2O, MgO, CaO, Fe2O3, TiO2, and ZnO; Based on the total mass of the deoxidizer, the content of active components in the deoxidizer is 8-14%, wherein the content of active component K2O is 1-5%; the content of active component CaO is 1-5%; the content of active component Fe2O3 is 1-5%; the content of active component TiO2 is 1-5%; and the content of active component ZnO is 1-5%. The method for preparing the multi-stage composite metal oxide deoxidizer comprises the following steps: (1) Mix the support and the active component precursor evenly; (2) Add nitric acid, citric acid, and carboxymethyl cellulose to deionized water, stir and dissolve, then pour into the mixture obtained in step (1), and continue to mix evenly; (3) Extruding the mixture obtained in step (2) multiple times, mixing evenly and then forming strips; (4) drying and calcining the product obtained in step (3) to obtain the desired deoxidizer; In step (2), the mass of the added nitric acid accounts for 3-6% of the mass of the support, the mass of the citric acid accounts for 2-5% of the mass of the support, and the mass of the carboxymethyl cellulose accounts for 2-5% of the mass of the support.

2. The application method of the multi-stage composite metal oxide deoxidizer according to claim 1, characterized in that: When the support contains aluminum oxide, its mass content is less than 60% of the total amount of the support.

3. The application method of the multi-stage composite metal oxide deoxidizer according to claim 1, characterized in that: Based on the total mass of the deoxidizer, the content of the active component K2O is 1-3%; the content of the active component CaO is 1-3%; the content of the active component Fe2O3 is 1-3%; the content of the active component TiO2 is 1-3%; and the content of the active component ZnO is 1-3%.

4. The application method of the multi-stage composite metal oxide deoxidizer according to claim 1, characterized in that: The drying and calcining are specifically as follows: drying at 60° C. for 3 h, drying at 120° C. for 6 h, and finally calcining at 500° C. for 5 h.

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