CN108273508A - A kind of preparation method of high-performance reforming of methane on Ni-Ce nickel-base catalyst - Google Patents

Abstract

Nickel nitrate is first reacted synthesis nickel hydroxide powder, then complex prepared by nickel hydroxide and glycine as presoma, with SiO by a kind of preparation method of high-performance reforming of methane on Ni-Ce nickel-base catalyst, this method with NaOH₂Or Al₂O₃As carrier, the methane reforming nickel-base catalyst of high activity and high stability is prepared for using excessive infusion process（Ni/SiO₂Or Ni/Al₂O₃）.The present invention has raw material nickel nitrate, NaOH, glycine and the carrier prepared used in catalyst（SiO₂Or Al₂O₃）It is cheap and easy to get, the advantages that preparation process condition is simple, is easily industrialized, and repeatability is good.Compared with traditional dipping technique, catalyst prepared by the method for the present invention not only shows higher CH₄Conversion ratio, and there is very high stability, significantly improve the activity and stability of methane reforming reaction.

Description

Preparation method of a high-performance nickel-based catalyst for methane reforming to synthesis gas

technical field

The invention belongs to the technical field of catalysts, and in particular relates to a preparation method of a high-performance nickel-based catalyst for reforming methane into synthesis gas.

Background technique

With the deepening of people's understanding of the greenhouse effect, the capture and effective utilization of CO ₂ , one of the most powerful greenhouse gases, has attracted increasing attention. Among them, CO ₂ and CH ₄ reforming (CDR) combined with clean utilization of natural gas or coalbed methane (mainly methane) to synthesis gas or hydrogen technology has received great attention and extensive research reports have been carried out. The CDR process utilizes two major greenhouse gases, CO ₂ and CH ₄ , which is of great significance to the reduction of greenhouse gas emissions, and the H ₂ /CO of the synthesis gas is ≤ 1, which can be used as carbonyl and organic oxygen-containing compound synthesis and Fischer-Tropsch (FT) The synthesis reaction is the raw material gas for the synthesis of long chain hydrocarbons. More importantly, compared with other _CO2 conversion and utilization technologies, CDR is expected to be directly applied to the reforming reaction of _CH4 and _CO2 in flue gas without pre-separation of _CO2 in flue gas. Therefore, the industrialization process of CDR reaction is of great significance for solving energy problems and realizing _CO2 emission reduction and efficient utilization. Studies have shown that catalyst deactivation caused by carbon deposition and sintering is the bottleneck for the industrial application of CDR. Therefore, a lot of research has been carried out around the stability of catalysts.

Studies have found that, except for Os, transition metals of group VIII have catalytic activity for methane reforming reaction, among which noble metals (such as Pt, Pd, Rh, Ir, etc.) have higher catalytic activity, stronger anti-coking ability, and higher stability. it is good. However, considering the catalytic performance and economic efficiency, Ni-based catalysts are the best. Therefore, how to improve the performance, especially the stability, of Ni-based catalysts has become one of the current research hotspots.

A comprehensive analysis of relevant literature reports shows that there are two key factors affecting the carbon deposition of Ni-based catalysts in CDR reactions, namely the particle size of Ni and its interaction with the support. Studies have shown that small particles of Ni can effectively inhibit the formation of carbon deposition, but when the size of Ni particles increases to more than 9 nm, the rate of carbon deposition on the catalyst surface will rapidly increase, resulting in catalyst deactivation. Therefore, obtaining highly dispersed Ni-based catalysts and suppressing the sintering of Ni under high-temperature reduction and reaction conditions by increasing the interaction between them and the support can effectively control the formation of carbon deposits. In view of the above key factors affecting the performance of Ni-based catalysts, researchers at home and abroad have adopted a variety of new strategies to improve the anti-sintering and anti-carbon deposition performance of Ni-based catalysts. A lot of innovative research has been done on changing the particle size of Ni and its interaction with the carrier, and some achievements have been made.

Contents of the invention

In order to overcome the deficiencies in the prior art, the purpose of this invention is to provide a kind of preparation method of high-performance methane reforming system synthesis gas nickel-based catalyst, with the stable complex that nickel hydroxide and glycine forms as precursor, SiO _or Al ₂ O ₃ as a support, a highly active and stable nickel-based catalyst for methane reforming was prepared by an excess impregnation method. Compared with the traditional impregnation method, the activity, especially the stability, of the methane reforming reaction can be obviously improved by using the catalyst prepared by the invention.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A preparation method of a high-performance methane reforming synthesis gas nickel-based catalyst, comprising the following steps:

1) Under stirring conditions at room temperature, add 0.2 mol/L NaOH aqueous solution dropwise to 0.1 mol/L nickel nitrate aqueous solution, stir for 30-60 minutes after the dropwise addition, centrifuge, wash with deionized water until neutral, 80-120 Dry at ℃ for 10-12 hours, and grind to obtain nickel hydroxide powder;

2) Add nickel hydroxide powder into 0.01-0.1 g/mL glycine aqueous solution under stirring condition of 50-80°C, and continue stirring for 1-4 hours to obtain nickel glycine complex solution;

3) Add SiO ₂ or Al ₂ O ₃ to the nickel glycine complex solution according to the Ni loading of 5% to 20%, stir at 50 to 80°C for 0.5 to 1.5 hours, and then use a rotary evaporator at 50 to Remove water at 80°C, dry at 80-120°C for 10-12 hours, calcinate at 500°C for 4 hours, press into tablets, granulate, and screen 40-60 mesh particles after calcining to obtain a nickel-based catalyst.

The molar ratio of nickel nitrate to NaOH in the step 1) is 1:2-2.5.

The molar ratio of nickel hydroxide to glycine in the step 2) is 1:2-3.

The stirring temperature in the step 3) is 80°C for 1-1.5 hours.

The calcination in step 3) was carried out at a rate of 5 ℃/min to 500 ℃ for 4 hours.

The beneficial effects of the present invention are:

The invention uses the stable complex formed by nickel hydroxide and glycine as a precursor, SiO ₂ or Al ₂ O ₃ as a carrier, and prepares a high-activity and high-stability nickel-based catalyst for methane reforming through an excessive impregnation method. Compared with the traditional impregnation method, the activity, especially the stability, of the methane reforming reaction can be obviously improved by using the catalyst prepared by the invention.

The raw materials used for preparing the catalyst in the invention are cheap and easy to obtain, the preparation process is simple, easy to realize industrialization, and has good repeatability.

Detailed ways

The present invention will be further described in detail below in conjunction with the examples, but the protection scope of the present invention is not limited to these examples.

Example 1

Under the condition of stirring at room temperature, add 25 mL 0.2 mol/L NaOH aqueous solution dropwise to 25 mL 0.1 mol/L nickel nitrate aqueous solution, continue to stir for 60 minutes after the dropwise addition, centrifuge, wash with deionized water until neutral, 100°C Dry for 12 hours to obtain nickel hydroxide powder. According to the Ni loading of 10%, 0.1755 g of nickel hydroxide powder was added to 8.6 mL of 0.05 g/mL glycine aqueous solution (the molar ratio of glycine to nickel hydroxide was 3) under the condition of stirring at 80 °C, and the stirring was continued for 2 hours , to obtain the nickel glycine complex impregnation solution. Add 1.00 g SiO ₂ to the glycine nickel complex impregnation solution, stir at 80°C for 1 hour, then use a rotary evaporator to remove water at 50°C, dry at 80°C for 12 hours, and increase the temperature at a rate of 5°C/min to Calcining at 500°C for 4 hours, tableting, granulation, and screening of 40-60 mesh particles to obtain a nickel-based catalyst.

Example 2

Under the condition of stirring at room temperature, add 30 mL 0.2 mol/L NaOH aqueous solution dropwise to 20 mL 0.1 mol/L nickel nitrate aqueous solution, continue to stir for 30 minutes after the dropwise addition, centrifuge, wash with deionized water until neutral, 120°C It was dried for 10 hours to obtain nickel hydroxide powder. According to the Ni loading of 5%, 0.0831 g of nickel hydroxide powder was added to 13 mL of 0.01 g/mL glycine aqueous solution (the molar ratio of glycine to nickel hydroxide was 2) under the stirring condition of 80 °C, and the stirring was continued for 2 hours. The impregnation solution of the nickel glycine complex was obtained. Add 1.00 g SiO ₂ to the nickel glycine complex impregnation solution, stir at 80°C for 1 hour, then use a rotary evaporator to remove water at 60°C, dry at 100°C for 12 hours, and increase the temperature at a rate of 5°C/min to Calcining at 500°C for 4 hours, tableting, granulation, and screening of 40-60 mesh particles to obtain a nickel-based catalyst.

Example 3

Under the condition of stirring at room temperature, add 25 mL 0.2 mol/L NaOH aqueous solution dropwise to 25 mL 0.1 mol/L nickel nitrate aqueous solution, continue to stir for 30 minutes after the dropwise addition, centrifuge, wash with deionized water until neutral, 100°C Dry for 12 hours to obtain nickel hydroxide powder. According to the Ni loading of 10%, add 0.1755 g of nickel hydroxide powder into 5.7 mL of 0.10 g/mL glycine aqueous solution (the molar ratio of glycine to nickel hydroxide is 4) under stirring condition at 80 °C, and continue stirring for 1 hour , to obtain the nickel glycine complex impregnation solution. Add 1.00 g SiO ₂ to the nickel glycine complex impregnation solution, stir at 100°C for 1 hour, then use a rotary evaporator to remove water at 70°C, dry at 120°C for 10 hours, and increase the temperature at a rate of 5°C/min to Calcining at 500°C for 4 hours, tableting, granulation, and screening of 40-60 mesh particles to obtain a nickel-based catalyst.

Example 4

Under the condition of stirring at room temperature, add 50 mL 0.2 mol/L NaOH aqueous solution dropwise to 50 mL 0.1 mol/L nickel nitrate aqueous solution, continue to stir for 60 minutes after the dropwise addition, centrifuge, wash with deionized water until neutral, 80°C Dry for 12 hours to obtain nickel hydroxide powder. According to the Ni loading of 20%, add 0.3949 g of nickel hydroxide powder into 4.0 mL of 0.08 g/mL glycine aqueous solution (the molar ratio of glycine to nickel hydroxide is 1) under stirring condition at 80 °C, and continue stirring for 0.5 hours , to obtain the nickel glycine complex impregnation solution. Then add 1.00 g SiO ₂ to the nickel glycine complex impregnation solution, stir at 100°C for 1 hour, then use a rotary evaporator to remove water at 80°C, dry at 100°C for 12 hours, and increase the temperature at a rate of 5°C/min to Calcining at 500°C for 4 hours, tableting, granulation, and screening of 40-60 mesh particles to obtain a nickel-based catalyst.

Example 5

Under the condition of stirring at room temperature, add 50 mL 0.2 mol/L NaOH aqueous solution dropwise to 50 mL 0.1 mol/L nickel nitrate aqueous solution, continue to stir for 60 minutes after the dropwise addition, centrifuge, wash with deionized water until neutral, 120°C It was dried for 10 hours to obtain nickel hydroxide powder. According to the Ni loading of 15%, add 0.2787 g of nickel hydroxide powder into 9.0 mL of 0.05 g/mL glycine aqueous solution (the molar ratio of glycine to nickel hydroxide is 2) under stirring condition at 80 °C, and continue stirring for 1 hour , to obtain the nickel glycine complex impregnation solution. Add 1.00 g Al ₂ O ₃ to the nickel glycine complex impregnation solution, stir at 100°C for 1 hour, then use a rotary evaporator to remove water at 60°C, and dry at 80°C for 12 hours, at a heating rate of 5°C/min Raise the temperature to 500°C for 4 hours, press into tablets, granulate, and screen 40-60 mesh particles to obtain a nickel-based catalyst.

Example 6

Under the condition of stirring at room temperature, add 25 mL 0.2 mol/L NaOH aqueous solution dropwise to 25 mL 0.1 mol/L nickel nitrate aqueous solution, continue to stir for 60 minutes after the dropwise addition, centrifuge, wash with deionized water until neutral, 100°C Dry for 12 hours to obtain nickel hydroxide powder. According to the Ni loading of 10%, 0.1755 g of nickel hydroxide powder was added to 5.4 mL of 0.08 g/mL glycine aqueous solution (the molar ratio of glycine to nickel hydroxide was 3) under the condition of stirring at 80 °C, and the stirring was continued for 0.5 hours , to obtain the nickel glycine complex impregnation solution. Add 1.00 g Al ₂ O ₃ to the nickel glycine complex impregnation solution, stir at 100°C for 2 hours, then use a rotary evaporator to remove water at 60°C, and dry at 100°C for 12 hours, at a heating rate of 5°C/min Raise the temperature to 500°C and roast for 4 hours, press into tablets, granulate, and sieve 40-60 mesh particles to obtain a nickel-based catalyst.

In order to verify the beneficial effect of the present invention, the inventor has carried out performance evaluation to the nickel-based catalyst prepared in embodiment 1～6, and concrete experiment situation is as follows:

Put 0.10 g of catalyst in a fixed bed reactor, feed H ₂ /N ₂ with a volume ratio of 20% under normal pressure, flow rate is 50 mL·min ^-1 , and the heating rate is 4 ℃·min ^-1 Raise from room temperature to 700 ℃, and reduce for 2.5 hours. Then, turn off H ₂ , continue to feed N ₂ , and raise the temperature to 750 °C at a rate of 2 °C·min ^-1 , and switch to the reaction gas (the volume ratio of CO ₂ and CH ₄ is 1:1) after the temperature is stable. mixed gas), the total amount of reaction gas is 100 mL·min ^-1 , under the conditions of P = 1.0 atm, T = 750 ℃, CO ₂ /CH ₄ = 1.0, space velocity = 60000 mL·g ^-1 ·h ^-1 Under the reaction, the gas after the reaction is detected and analyzed by the chromatograph of Zhejiang Fuli GC9720 II thermal conductivity cell detector (the chromatographic columns are 5A and PQ columns). The experimental results are shown in Table 1.

Table 1 Methane-carbon dioxide reforming reaction performance of different catalysts catalyst Initial methane conversion rate (%) Carbon dioxide initial conversion rate (%) Methane conversion rate after 20 hours (%) Carbon dioxide conversion rate after 20 hours (%) Example 1 84.7 93.8 83.2 93.1 Example 2 80.6 90.1 78.5 88.3 Example 3 80.5 91.7 77.6 89.5 Example 4 85.1 94.5 70.6 79.7 Example 5 82.6 93.1 82.0 90.9 Example 6 83.0 92.1 82.1 90.2

It can be seen from Table 1 that the Ni/ _SiO2 and Ni/ _Al2O3 catalysts prepared by the method of the present invention have high reactivity to methane reforming reaction, and the initial conversion rates _{of CH4} and _CO2 are as high as 80% and 90% respectively above. After 20 h of reaction, the _CH4 and _CO2 conversions were still higher than 70% and 79%.

Claims (5)

1. a kind of preparation method of high-performance reforming of methane on Ni-Ce nickel-base catalyst, which is characterized in that include the following steps：

1）Under the conditions of being stirred at room temperature, 0.2 isometric mol/L NaOH aqueous solutions are added drop-wise to 0.1 mol/L nickel nitrate water In solution, continue stirring after being added dropwise to complete 30~60 minutes, centrifuges solid, then be washed with deionized water to neutrality, 80~ It is 10~12 hours dry in 120 DEG C of baking ovens, nickel hydroxide powder is obtained after grinding；

2）Under 50~80 DEG C of stirring conditions, nickel hydroxide powder is added to the glycine solution of 0.01~0.1 g/mL In, continue stirring 1~4 hour, obtains nickel glycinate complex solution；

3）According to Ni load capacity 5%~20%, by SiO₂Or Al₂O₃It is added in nickel glycinate complex solution, in 50~80 DEG C of items Continue stirring under part 0.5~1.5 hour, then removes water, 80~120 DEG C of dryings 10~12 at 50~80 DEG C with Rotary Evaporators Hour, 500 DEG C roast 4 hours, and tabletting, granulation, the particle for screening 40~60 mesh, obtain Ni/SiO after roasting₂Or Ni/Al₂O₃It urges Agent.

2. a kind of preparation method of high-performance reforming of methane on Ni-Ce nickel-base catalyst according to claim 1, special Sign is, the step 1）The molar ratio of middle nickel nitrate and NaOH are 1:2~2.5.

3. a kind of preparation method of high-performance reforming of methane on Ni-Ce nickel-base catalyst according to claim 1, special Sign is, the step 2）The molar ratio of middle nickel hydroxide and glycine is 1:2~3.

4. the preparation method of high-performance methane reforming nickel-base catalyst according to claim 1, which is characterized in that described Step 3）Middle whipping temp is to stir 1-1.5 hours under the conditions of 80 DEG C.

5. the preparation method of high-performance methane reforming nickel-base catalyst according to claim 1, which is characterized in that described Step 3）Middle roasting rises to 500 DEG C with 5 DEG C/min of heating rate and roasts 4 hours.