Method for removing oxycarbide in hydrogen

Abstract

The invention belongs to the technical field of hydrogen purification, and relates to a method for removing oxycarbide in hydrogen. The method comprises the following steps: carrying out contact reaction on hydrogen-rich gas containing oxycarbide and a nickel catalyst, wherein the nickel catalyst comprises a carrier aluminum oxide and an active component nickel dispersed on the carrier aluminum oxide; the carrier aluminum oxide is prepared by adopting rotation strengthening equipment, and the preparation method comprises the following steps: jointly pumping an aluminum sulfate solution and an aluminum hydroxide-sodium hydroxide mixed solution into a rotation strengthening reactor by adopting a liquid pump to form suspension slurry; spraying the suspension slurry into the inner side of a silk screen filler through a solution mixing distributor, and rotating the silk screen filler to shear the suspension slurry into tiny units; enabling the tiny units to enter a crystallization kettle through an outlet of the rotary intensified reactor, crystallizing to obtain a crystallized material, filtering, washing, drying, and roasting to obtain the alumina carrier. The carrier aluminum oxide adopted by the invention has higher reaction activity in the application of removing trace oxycarbide in hydrogen.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen purification, and in particular, relates to a method for removing carbon oxides from hydrogen. Background Art

[0002] Methanation is the simplest reaction in Fischer-Tropsch synthesis and is mainly used in the fields of ethylene industry, synthetic ammonia, hydrogen purification and coal gasification. It aims to convert COx into methane or remove the impurity COx in the raw gas to achieve the purpose of purification. Natural gas is one of the fossil energy sources and is mainly used in the chemical and fuel fields. Its main component methane can be obtained by catalytic conversion of synthesis gas (COx, H2). As the simplest Fischer-Tropsch synthesis reaction, methanation has the advantages of high calorific value, high conversion rate, single product and good economic benefits.

[0003] The current industrial methanation catalyst is mainly composed of Ni, Ru active ingredients, additives and carriers, and is prepared by traditional impregnation methods. The main process is to immerse the carrier in a solution containing active components. After a period of contact, the remaining liquid is removed by filtering, evaporation and other methods. The active components are loaded on the surface of the carrier in the form of ions or compound microcrystals, and then processed by activation processes such as drying and calcination to obtain the final catalyst product. For example, CN103055874A discloses a methanation catalyst, and the preparation steps are to impregnate an equal amount of a water-soluble salt solution containing nickel and an additive on an alumina carrier, and then dry and calcine. CN102319574A also discloses a methanation catalyst, which also uses an impregnation method to load nickel on alumina modified by cerium oxide. The main features of the impregnation method are: (1) using a carrier with a pre-existing shape and size, no need for subsequent catalyst shaping operations; (2) the impregnation method can load one or several active components on the carrier; (3) the pore structure of the carrier basically determines the pore structure and specific surface area of ​​the catalyst. However, it is worth noting that in order to obtain a highly active catalyst, multiple impregnation and calcination operations are often required, resulting in greater energy consumption and carbon emissions, which does not meet the current energy conservation and carbon reduction goals.

[0004] CN106492864B discloses a carbon-supported CO methanation catalyst that can achieve a large nickel loading at one time. However, the preparation process of the catalyst requires high-temperature pyrolysis under oxygen-free conditions, which produces a large amount of hydrocarbon waste gas and tar, and the pyrolysis temperature is relatively high. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a method for removing carbon oxides from hydrogen. The carrier alumina used can be prepared into a high-content nickel catalyst by one-time impregnation, and has high reaction activity in the application of removing trace carbon oxides from hydrogen.

[0006] In order to achieve the above object, the present invention provides a method for removing carbon oxides from hydrogen, wherein hydrogen-rich gas containing carbon oxides is contacted with a nickel catalyst for reaction, wherein the nickel catalyst comprises a carrier alumina and an active component nickel dispersed thereon;

[0007] The carrier alumina is prepared by a rotary strengthening device, which includes a rotary strengthening reactor, at least two liquid pumps, a crystallization kettle and a motor;

[0008] The rotary enhanced reactor comprises a rotary enhanced reaction device shell, a wire mesh filler and a solution mixing distributor, wherein the wire mesh filler is located inside the rotary enhanced reaction device shell, and a certain space is formed inside the wire mesh filler, the solution mixing distributor is placed in the space, and the motor is connected to the wire mesh filler;

[0009] The liquid pump is provided with a liquid pump discharge pipeline, the rotary enhanced reaction device housing is provided with a rotary enhanced reactor inlet and a rotary enhanced reactor outlet, the liquid pump discharge pipeline is connected to the solution mixing distributor through the rotary enhanced reactor inlet, and the rotary enhanced reactor outlet is connected to the crystallization kettle;

[0010] The steps include:

[0011] (1) using a liquid pump to pump the aluminum sulfate solution and the aluminum hydroxide-sodium hydroxide mixed solution from the inlet of the rotary intensified reactor into the rotary intensified reactor to form a suspension;

[0012] (2) spraying the suspension into the inner side of the wire mesh filler through a solution mixing distributor, and rotating the wire mesh filler driven by a motor to shear the suspension into small units;

[0013] (3) The micro-unit obtained in step (2) enters a crystallization kettle through the outlet of a rotary enhanced reactor for crystallization to obtain a crystallized material. The crystallized material is filtered, washed, dried, and then calcined to obtain the alumina carrier.

[0014] In the present invention, the preparation method of the carrier alumina is as follows Figure 1 The schematic diagram of the rotary intensified impregnation equipment is shown. During the intensified hydrolysis process, the reaction liquid is dispersed into fine droplets and liquid films on the high-speed rotating screen, and the microenvironment of the precipitation reaction is more uniform, thereby obtaining crystal seeds of uniform size. After crystallization and calcination, a carrier alumina with stable structure and performance is obtained.

[0015] According to the present invention, preferably, the concentration of the aluminum sulfate solution is 0.5-2 mol / L.

[0016] According to the present invention, preferably, the aluminum hydroxide concentration in the aluminum hydroxide-sodium hydroxide mixed solution is 0.5-1 mol / L, and the sodium hydroxide concentration is 1-1.5 mol / L.

[0017] According to the present invention, preferably, the flow ratio of the aluminum sulfate solution to the aluminum hydroxide-sodium hydroxide mixed solution is 1:(0.5-2).

[0018] According to the present invention, preferably, in step (2), the wire mesh filler rotates at a speed of 2800 to 3200 rpm.

[0019] According to the present invention, preferably, the crystallization conditions include: a temperature of 60-100° C. and a time of 2-24 h.

[0020] According to the present invention, preferably, the drying conditions include: a temperature of 60-120° C. and a time of 4-12 hours.

[0021] According to the present invention, preferably, the calcination conditions include: a temperature of 400-800° C. and a time of 4-8 hours.

[0022] According to the present invention, preferably, the alumina carrier has the following characteristics: a specific surface area of ​​300 to 800 m 2 / g, preferably 400 to 700 m 2 / g, and the average pore diameter is 10 to 40 nm, preferably 20 to 35 nm.

[0023] According to the present invention, preferably, the method for preparing the nickel catalyst comprises the following steps:

[0024] a) immersing the carrier alumina into a nickel salt solution by an excessive impregnation method to obtain a carrier alumina impregnated with a nickel salt solution;

[0025] b) directly drying and calcining the carrier alumina impregnated with the nickel salt solution obtained in step a) to obtain the nickel catalyst.

[0026] According to the present invention, preferably, in step a), the nickel salt solution is a water-soluble nickel salt solution, preferably at least one of a nickel nitrate solution, a nickel carbonate solution and a nickel sulfate solution.

[0027] More preferably, the concentration of the nickel salt solution is 3-5 mol / L, and the immersion time is 30-120 min.

[0028] According to the present invention, preferably, in step b), the drying conditions include: temperature of 110-130° C., time of 4-12 h; the calcination conditions include: temperature of 600-800° C., time of 4-8 h.

[0029] According to the present invention, preferably, the content of the active component nickel is 30-70wt%, preferably 40-60wt%, and the content of the carrier alumina is 30-70wt%, preferably 40-60wt%.

[0030] According to the present invention, preferably, the contact reaction conditions include: reaction temperature of 150-180°C, reaction pressure of 1-4 MPa, gas space velocity of 1000-3000 h -1 , the carbon oxide concentration in the inlet gas before the reaction is less than 3000ppm, and the carbon oxide concentration in the gas after the reaction is less than 1ppm.

[0031] The invention adopts enhanced hydrolysis to prepare the carrier alumina, and the carrier alumina can be used to prepare a high-content nickel catalyst through one-time impregnation, which is used in the application of removing trace carbon oxides in hydrogen and has high reaction activity.

[0032] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0034] Figure 1 Schematic diagram of the rotary strengthening equipment.

[0035] Description of Reference Numerals

[0036] 1-1, aluminum sulfate solution; 1-2, aluminum hydroxide-sodium hydroxide mixture; 1-3, 1-4, liquid pump; 1-5, solution mixing distributor; 1-6, wire mesh filler; 1-7, rotating intensified reaction device housing; 1-8, reactant outlet; 1-9, crystallization kettle; 1-10, motor. DETAILED DESCRIPTION

[0037] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0038] The present invention will be further described below in conjunction with embodiments, but the scope of the present invention is not limited to these embodiments.

[0039] The test instruments and test conditions used in the examples are as follows:

[0040] The BET surface area and average pore size of the nickel catalyst were measured by N2 adsorption-desorption method.

[0041] The sources of raw materials used in the examples are as follows:

[0042] Other reagents used were commercially available and of analytical grade.

[0043] Example 1

[0044] Carrier alumina: Prepare 0.5 mol / L aluminum sulfate aqueous solution, aluminum hydroxide and sodium hydroxide are 1 mol / and 1 mol / respectively, the flow ratio of aluminum sulfate solution to aluminum hydroxide-sodium hydroxide mixed solution is 1:0.7, turn on the motor to drive the rotating filler, the speed is 3000 rpm, the two liquids are pumped into the liquid distributor through the horizontal flow pump, mixed and sprayed into the enhanced reactor, under the shearing action of the rotating filler, the mixed reaction liquid is sheared into tiny suspension droplets, and finally enters the crystallization kettle from the bottom of the enhanced reactor, and crystallizes at 80°C for 20 hours. After crystallization, it is filtered and washed with deionized water, and then dried at 80°C for 20 hours. Finally, the dried powder is calcined in an air atmosphere at 400°C to obtain an alumina carrier. The specific surface area of ​​the alumina carrier obtained by the enhanced hydrolysis method is 698m by the N2 adsorption and desorption method. 2 / g, and the average pore size is 21nm.

[0045] Nickel catalyst: The above-mentioned carrier alumina was immersed in a 4 mol / L nickel nitrate aqueous solution, filtered after 30 min, dried at 120° C., and calcined at 400° C. to obtain a nickel catalyst with a NiO loading of 55%, which was recorded as A-1.

[0046] Example 2

[0047] Carrier alumina: Prepare 2 mol / L aluminum sulfate aqueous solution, aluminum hydroxide and sodium hydroxide mixed solution of 0.5 mol / and 1.5 mol / respectively, the flow ratio of aluminum sulfate solution to aluminum hydroxide-sodium hydroxide mixed solution is 1:2, turn on the motor to drive the rotating filler, the speed is 3000 rpm, the two liquids are pumped into the liquid distributor through the horizontal flow pump, mixed and sprayed into the enhanced reactor, under the shearing action of the rotating filler, the mixed reaction liquid is sheared into tiny suspension droplets, and finally enters the crystallization kettle from the bottom of the enhanced reactor, and crystallizes at 80°C for 20 hours. After crystallization, it is filtered and washed with deionized water, and then dried at 80°C for 20 hours. Finally, the dried powder is calcined in an air atmosphere at 500°C to obtain an alumina carrier. The specific surface area of ​​the alumina carrier obtained by the enhanced hydrolysis method is 412m by N2 adsorption and desorption method. 2 / g, and the average pore size is 32nm.

[0048] Nickel catalyst: The above-mentioned carrier alumina was immersed in a 4 mol / L nickel nitrate aqueous solution, filtered after 30 min, dried at 120° C., and calcined at 400° C. to obtain a nickel catalyst with a NiO loading of 48%, which was recorded as A-2.

[0049] Example 3

[0050] Carrier alumina: Prepare 1 mol / L aluminum sulfate aqueous solution, aluminum hydroxide and sodium hydroxide mixed solution with 0.5 mol / and 1.5 mol / respectively, the flow ratio of aluminum sulfate solution to aluminum hydroxide-sodium hydroxide mixed solution is 1:1.2, turn on the motor to drive the rotating filler, the speed is 3000 rpm, the two liquids are pumped into the liquid distributor through the horizontal flow pump, mixed and sprayed into the enhanced reactor, under the shearing action of the rotating filler, the mixed reaction liquid is sheared into tiny suspension droplets, and finally enters the crystallization kettle from the bottom of the enhanced reactor, and crystallizes at 80°C for 20 hours. After crystallization, it is filtered and washed with deionized water, and then dried at 80°C for 20 hours. Finally, the dried powder is calcined in an air atmosphere at 800°C to obtain an alumina carrier. The specific surface area of ​​the alumina carrier obtained by the enhanced hydrolysis method is 581m by N2 adsorption and desorption method. 2 / g, and the average pore size is 23nm.

[0051] Nickel catalyst: The above-mentioned carrier alumina was immersed in a 4 mol / L nickel nitrate aqueous solution, filtered after 30 min, dried at 120° C., and calcined at 450° C. to obtain a nickel catalyst with a NiO loading of 51%, which was recorded as A-3.

[0052] Comparative Example 1

[0053] Commercial alumina carrier (Inokai JHZ-04) was used, with a BET specific surface area of ​​239 m 2 / g, and the average pore size is 13nm.

[0054] The commercial alumina carrier was immersed in a 4 mol / L nickel nitrate aqueous solution, filtered after 30 min, dried at 120° C., and calcined at 450° C. After one immersion, a nickel catalyst with a NiO loading of 19% was obtained, which was recorded as D-1.

[0055] Comparative Example 2

[0056] Commercial alumina carrier (Inokai JHZ-04) was used, with a BET specific surface area of ​​239 m 2 / g, and the average pore size is 13nm.

[0057] The commercial alumina carrier was immersed in a 4 mol / L nickel nitrate aqueous solution, filtered after 30 min, dried at 120° C., and calcined at 450° C. After multiple immersions, a nickel catalyst with a NiO loading of 43% was obtained, which was recorded as D-2.

[0058] Comparative Example 3

[0059] The carrier alumina was prepared by ordinary co-precipitation method: 1 mol / L aluminum sulfate aqueous solution, aluminum hydroxide and sodium hydroxide were mixed in the amounts of 0.5 mol / L and 1.5 mol / L, respectively, and the flow ratio of aluminum sulfate solution to aluminum hydroxide-sodium hydroxide mixed solution was 1:1.2, and they were added dropwise into a stirred reactor. The reaction precipitate was transferred to a crystallization kettle and crystallized at 80°C for 20 hours. After crystallization, it was filtered and washed with deionized water, and then dried at 80°C for 20 hours. Finally, the dried powder was calcined in an air atmosphere at 500°C to obtain an alumina carrier. The specific surface area of ​​the alumina carrier obtained by the enhanced hydrolysis method was measured by N2 adsorption-desorption method to be 406m 2 / g, and the average pore size is 13nm.

[0060] Nickel catalyst: The above-mentioned carrier alumina was immersed in a 4 mol / L nickel nitrate aqueous solution, filtered after 30 min, dried at 120° C., and calcined at 450° C. A nickel catalyst with a NiO loading of 21% was obtained by one immersion, which was recorded as D-3.

[0061] Test Case

[0062] 10 ml of the catalyst of Examples 1-6 and Comparative Examples 1-2 were respectively loaded into a stainless steel fixed bed reactor, and high-purity hydrogen was introduced at a flow rate of 300 ml / min, and the temperature was heated to 450° C. to reduce the catalyst for 4 hours; high-purity nitrogen was switched at a flow rate of 300 ml / min, and when the temperature dropped to a set value, raw gas was introduced, and the CO content in the raw gas was 1000 ppm. Other conditions are listed in Table 1. The composition of the gas after the reaction was analyzed by gas chromatography, and the detector was FID.

[0063] Table 1

[0064]

[0065] As can be seen from Table 1, the carrier alumina prepared by the enhanced hydrolysis method can achieve a high nickel loading in a single impregnation operation and achieve a high CO removal efficiency. Compared with commercial alumina carriers and alumina carriers prepared by ordinary stirring precipitation method, the preparation steps can be simplified, the loading capacity of a single impregnation is significantly increased, the production cost of the catalyst is effectively reduced, and the target requirements of energy conservation, emission reduction and carbon reduction can be achieved.

[0066] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0067] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

Claims

1. A method for removing carbon oxides from hydrogen, characterized in that: The hydrogen-rich gas containing carbon oxides is contacted with a nickel catalyst for reaction, wherein the nickel catalyst comprises a carrier alumina and an active component nickel dispersed thereon; The carrier alumina is prepared by a rotary strengthening device, which includes a rotary strengthening reactor, at least two liquid pumps, a crystallization kettle and a motor; The rotary enhanced reactor comprises a rotary enhanced reaction device shell, a wire mesh filler and a solution mixing distributor, wherein the wire mesh filler is located inside the rotary enhanced reaction device shell, and a certain space is formed inside the wire mesh filler, the solution mixing distributor is placed in the space, and the motor is connected to the wire mesh filler; The liquid pump is provided with a liquid pump discharge pipeline, the rotary enhanced reaction device housing is provided with a rotary enhanced reactor inlet and a rotary enhanced reactor outlet, the liquid pump discharge pipeline is connected to the solution mixing distributor through the rotary enhanced reactor inlet, and the rotary enhanced reactor outlet is connected to the crystallization kettle; The steps include: (1) using a liquid pump to pump the aluminum sulfate solution and the aluminum hydroxide-sodium hydroxide mixed solution from the inlet of the rotary intensified reactor into the rotary intensified reactor to form a suspension; (2) spraying the suspension into the inner side of the wire mesh filler through a solution mixing distributor, and rotating the wire mesh filler driven by a motor to shear the suspension into small units; (3) The micro-unit obtained in step (2) enters a crystallization kettle through the outlet of a rotary enhanced reactor for crystallization to obtain a crystallized material. The crystallized material is filtered, washed, dried, and then calcined to obtain the alumina carrier.

2. The method for removing carbon oxides from hydrogen according to claim 1, wherein: The concentration of the aluminum sulfate solution is 0.5-2 mol / L; The aluminum hydroxide-sodium hydroxide mixed solution has an aluminum hydroxide concentration of 0.5-1 mol / L and a sodium hydroxide concentration of 1-1.5 mol / L; The flow ratio of the aluminum sulfate solution to the aluminum hydroxide-sodium hydroxide mixed solution is 1:(0.5-2).

3. The method for removing carbon oxides from hydrogen according to claim 1, wherein: In step (2), the wire mesh filler rotates at a speed of 2800 to 3200 rpm.

4. The method for removing carbon oxides from hydrogen according to claim 1, wherein: In step (3), the crystallization conditions include: temperature of 60-100° C. and time of 2-24 h; The drying conditions include: temperature of 60-120°C and time of 4-12h; The calcination conditions include: a temperature of 400-800° C. and a time of 4-8 hours.

5. The method for removing carbon oxides from hydrogen according to claim 1, wherein: The alumina carrier has the following characteristics: a specific surface area of ​​300 to 800 m 2 / g, preferably 400 to 700 m 2 / g, and the average pore diameter is 10 to 40 nm, preferably 20 to 35 nm.

6. The method for removing carbon oxides from hydrogen according to any one of claims 1 to 5, wherein: The preparation method of the nickel catalyst comprises the following steps: a) immersing the carrier alumina into a nickel salt solution by an excessive impregnation method to obtain a carrier alumina impregnated with a nickel salt solution; b) directly drying and calcining the carrier alumina impregnated with the nickel salt solution obtained in step a) to obtain the nickel catalyst.

7. The method for removing carbon oxides from hydrogen according to claim 6, wherein: In step a), the nickel salt solution is a water-soluble nickel salt solution, preferably at least one of a nickel nitrate solution, a nickel carbonate solution and a nickel sulfate solution; The concentration of the nickel salt solution is 3-5 mol / L, and the immersion time is 30-120 min.

8. The method for removing carbon oxides from hydrogen according to claim 6, wherein: In step b), the drying conditions include: temperature of 110-130° C. and time of 4-12 h; The calcination conditions include: temperature of 600-800°C and time of 4-8h.

9. The method for removing carbon oxides from hydrogen according to claim 6, wherein: The content of nickel as the active component is 30-70 wt%, preferably 40-60 wt%, and the content of alumina as the carrier is 30-70 wt%, preferably 40-60 wt%.

10. The method for removing carbon oxides from hydrogen according to claim 1, wherein: The conditions of the contact reaction include: reaction temperature of 150-180°C, reaction pressure of 1-4 MPa, gas space velocity of 1000-3000 h -1 , the carbon oxide concentration in the inlet gas before the reaction is less than 3000ppm, and the carbon oxide concentration in the gas after the reaction is less than 1ppm.

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