Natural gas-steam reforming hydrogen production catalyst as well as preparation method and application thereof

Abstract

The invention discloses a natural gas-steam reforming hydrogen production catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: dropwise adding an acid solution into water glass with SiO2 solubility of 8-15% or dropwise adding the water glass into the acid solution for acidification, controlling the pH value at the end point of acidification to be 6-8, stirring for 0.5-3 hours, and performing primary aging at 60-90 DEG C for 1-8 hours; then adding 8-15% by mass of sulfuric acid to adjust the pH value of the slurry to 1-3, carrying out secondary aging at room temperature for 1-8 hours, and carrying out suction filtration, washing and drying on the slurry to obtain a macroporous silica gel carrier; and dipping the macroporous silica gel carrier in a 1-10mol / L nickel salt precursor solution, and drying and calcining to obtain the loaded nickel-based macroporous silica gel catalyst. The method is simple in preparation process and low in cost, has good reforming hydrogen production reaction activity, can realize utilization of natural gas methane resources, and has certain industrial application potential.

Description

Technical Field

[0001] The present invention relates to the field of natural gas reforming hydrogen production catalysts, and in particular to a natural gas-steam reforming hydrogen production catalyst, a preparation method and an application thereof. Background Art

[0002] The main component of natural gas is methane, which is the simplest alkane. Natural gas itself can be used directly as an energy source. It is also one of the basic raw materials for modern chemical industry. It has many uses such as producing methanol, acetylene, synthetic fertilizers, oil products, hydrogen, carbon materials, etc. With the gradual deepening of domestic offshore gas field exploration and development in recent years, a wide range of natural gas sources have been provided. Hydrogen is widely regarded as a low-carbon energy carrier in the future because of its highest specific energy, clean combustion products, and ability to be used in fuel cells. Natural gas reforming to produce hydrogen is currently the most common and largest source of hydrogen in industry, so the development of new natural gas reforming hydrogen production catalysts has high industrial value.

[0003] About 50% of the world's annual hydrogen production is produced from natural gas, which includes natural gas thermal cracking, natural gas-CO2 dry reforming, and natural gas-steam reforming. Natural gas-steam reforming is one of the more mature process routes. According to a report by China National Offshore Oil Corporation [International Journal of Hydrogen Energy 48(2023)18601-18611], natural gas reforming produces 1m3 of hydrogen per tonne. 3 Hydrogen uses 0.44-0.48m3 of natural gas, which has the advantage of high raw material utilization compared to other processes. In addition, due to the improvement of mining technology in recent years, non-traditional natural gas such as methane hydrate and shale gas have also been included in the targets that can be mined, providing a wider range of raw material sources for the natural gas hydrogen production process.

[0004] In summary, natural gas steam reforming reaction can achieve high-value utilization of natural gas and alleviate the problem of difficulty in utilizing natural gas resources. However, the current natural gas steam reforming reaction has problems such as easy carbon deposition and easy loss of active metals caused by steam. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a natural gas-steam reforming hydrogen production catalyst and a preparation method and application thereof. The catalyst uses nickel as an active center and adopts macroporous silica gel as a carrier to ensure smooth mass transfer of reactants while improving the volumetric carbon capacity of the catalyst, thereby improving the stability of the catalyst. Moreover, the silanol group of the silica gel material can anchor the nickel metal active center, which is conducive to further improving the service life of the catalyst and the activity of the natural gas-steam reforming reaction.

[0006] In a first aspect, the present invention provides a method for preparing a natural gas-steam reforming hydrogen production catalyst, which is achieved by adopting the following technical scheme.

[0007] A method for preparing a natural gas-steam reforming hydrogen production catalyst comprises the following steps:

[0008] S1. Preparation of macroporous silica carrier:

[0009] The acid solution is dripped into a water glass solution with a SiO2 solubility of 8-15%, or the water glass is dripped into the acid solution for acidification, the pH value of the acidification end point is controlled to be 6-8, and after stirring for 0.5-3h, an aging is performed at 60-90°C for 1-8h; then, sulfuric acid with a mass fraction of 8-15% is added to adjust the pH of the slurry to 1-3, and a secondary aging is performed at room temperature for 1-8h. The slurry is filtered, washed, and dried to obtain a macroporous silica gel carrier;

[0010] S2. Nickel-based active component loading

[0011] The macroporous silica gel carrier prepared in step S1 is immersed in a 1-10 mol / L nickel salt precursor solution, with a loading amount of 0.5-10 wt % based on Ni, and then dried and calcined to obtain a loaded nickel-based macroporous silica gel catalyst.

[0012] Furthermore, in step S1, a macroporous silica gel carrier is prepared by a parallel flow method, and the preparation method is as follows: desalted water is used as a base liquid, and water glass with a SiO2 solubility of 8-15% and an acid solution are added to the base liquid simultaneously using a diaphragm pump, and the pH of the neutralization process is controlled at 6-8 by adjusting the dripping speed of the acid solution and the silicon source; after the addition is completed, the mixture is stirred for 0.5-4h, and aged at 60-90°C for 1-8h; after one aging, the pH of the slurry is adjusted to 1-3 using sulfuric acid with a mass fraction of 8-15%, and aged at room temperature for 1-8h. The obtained slurry is filtered, washed, and dried to obtain a macroporous silica gel carrier.

[0013] Furthermore, in step S1, the acid solution is selected from sulfuric acid, formic acid, acetic acid, hydrochloric acid, nitric acid or phosphoric acid; the mass fraction of sulfuric acid is 5-20%, and the mass fraction of formic acid, acetic acid, hydrochloric acid, nitric acid and phosphoric acid is 8-15%.

[0014] Furthermore, in step S1, the slurry is filtered and then washed with desalted water, and dried at 100-120° C. for 6-12 hours.

[0015] Furthermore, in step S2, the precursor nickel salt is selected from one or a mixture of nickel nitrate, nickel oxalate, nickel acetate, and nickel formate.

[0016] Furthermore, in step S2, the impregnation liquid uses a mixture of one or more of water, ethanol and methanol as the solvent; nitric acid is added as an acidifier during the preparation of the impregnation liquid, and the volume ratio of nitric acid to the impregnation liquid is (1-10):50 to inhibit the hydrolysis process of the nickel salt.

[0017] Furthermore, in step S2, the drying process temperature is 80-120° C. and the drying time is 4-10 hours.

[0018] Furthermore, in step S2, the high temperature calcination process uses one or a mixture of air, oxygen, nitrogen, etc., the calcination temperature is 300-400° C., and the calcination time is 2-8 hours.

[0019] In a second aspect, the present invention provides a natural gas-steam reforming hydrogen production catalyst, which is achieved by adopting the following technical solution.

[0020] A natural gas-steam reforming hydrogen production catalyst prepared by the above preparation method.

[0021] In a third aspect, the present invention provides a use of a natural gas-steam reforming hydrogen production catalyst, which is achieved by adopting the following technical solution.

[0022] An application of the above-mentioned natural gas-steam reforming hydrogen production catalyst in the reforming reaction of natural gas and steam.

[0023] This application has the following beneficial effects.

[0024] The catalyst prepared by the present invention has a macroporous structure, which can significantly improve the volumetric carbon capacity of the catalyst and has good mass transfer capacity. In addition, the silanol groups of the silica gel carrier can effectively improve the anchoring of metal sites and reduce the loss of metal active components during the use of the catalyst. The present invention can achieve effective utilization of natural gas resources through catalytic conversion, produce green energy carriers and basic chemical raw materials such as hydrogen, and obtain considerable benefits while achieving high-value utilization of resources. DETAILED DESCRIPTION

[0025] The present patent application is further described below in conjunction with embodiments.

[0026] The materials used in the preparation process of the following examples were not further processed unless otherwise specified and were purchased from commercial sources.

[0027] Example 1

[0028] A method for preparing a natural gas-steam reforming hydrogen production catalyst comprises the following steps:

[0029] (1) Preparation of catalyst carrier: Weigh 1 kg of water glass (SiO2 solubility 10%) and 400 g of desalted water as silicon source, and prepare 1 kg of 8% mass fraction sulfuric acid as acid solution. Gradually add the acid solution to the silicon source and stir at 50 Hz during the addition process. Control the end point pH = 7. Continue stirring for 1 hour after the addition. After the stirring is completed, perform an aging at 60°C for 2 hours. After the first aging, the pH of the solution will gradually rise. Continue to add 8% mass fraction sulfuric acid solution to adjust the slurry pH to 2. After a secondary aging process of 12 hours at room temperature, wash and filter to obtain silica gel powder.

[0030] (2) The solid silica gel obtained in step (1) can be used as a catalyst carrier after being dried at 120° C. for 8 h.

[0031] (3) The support obtained in step (2) was impregnated with a 5 mol / L nickel nitrate aqueous solution as the impregnation solution, with a loading of 5 wt %. The impregnated sample was placed in an oven at 100° C. for 12 h, and then calcined in a muffle furnace at 350° C. for 4 h to decompose the precursor salt, thereby obtaining a nickel-based macroporous silica gel catalyst.

[0032] Example 2

[0033] A method for preparing a natural gas-steam reforming hydrogen production catalyst is different from that of Example 1 in that: step (1) uses a parallel flow method to prepare a carrier, and the specific steps are as follows:

[0034] Prepare 200g of desalted water as the base liquid, and prepare 1200g of water glass (10% SiO2 solubility) + 400g of desalted water as the alkali liquid and 1200g of 8% sulfuric acid as the acid liquid. Use a diaphragm pump to synchronously drip the above two liquids into the base liquid, and control the simultaneous dripping. Use a 50Hz frequency to stir during the dripping process. After the dripping is completed, stir for 4 hours and then place it at 80℃ for stirring and aging for 4 hours. After the first aging, use 12% sulfuric acid to acidify the slurry to reduce the pH to 2 and then perform a second aging for 8 hours. After aging, filter and wash to obtain silica gel powder.

[0035] Example 3

[0036] A method for preparing a natural gas-steam reforming hydrogen production catalyst, which is different from Example 1 in that: in step (1), the primary aging temperature is 80° C., the aging time is 4 hours, and the remaining operating steps are the same as Example 1.

[0037] Example 4

[0038] A method for preparing a natural gas-steam reforming hydrogen production catalyst is different from that of Example 1 in that: in step (1), 8% by mass hydrochloric acid is prepared as an acid solution and dripped into a silicon source, and the remaining steps are the same as those of Example 1.

[0039] Example 5

[0040] A method for preparing a natural gas-steam reforming hydrogen production catalyst is different from that of Example 1 in that: in step (1), a similarly prepared silicon source is used as a base liquid, 8% sulfuric acid is gradually added to the silicon source, and the pH value is adjusted to 7. The remaining steps are the same as those of Example 1.

[0041] Example 6

[0042] A method for preparing a natural gas-steam reforming hydrogen production catalyst, which is different from Example 1 in that the silica gel powder obtained in step (2) is dried at 100° C. for 10 hours, and the remaining steps are the same as Example 1.

[0043] Example 7

[0044] A method for preparing a natural gas-steam reforming hydrogen production catalyst, which is different from Example 1 in that: in step (3), a 5 mol / L nickel acetate aqueous solution is used as an impregnation liquid, and the loading amount is 5 wt%. The impregnated sample is placed in a 100° C. oven to dry for 12 h, and then placed in a muffle furnace to calcine at 350° C. for 4 h to calcine and decompose the precursor salt to obtain a nickel-based macroporous silica gel catalyst. The remaining steps are the same as Example 1.

[0045] Example 8

[0046] A method for preparing a natural gas-steam reforming hydrogen production catalyst, which is different from that in Example 1 in that: in step (3), a 5 mol / L nickel nitrate aqueous solution is used as an impregnation liquid, the loading amount is 10 wt%, the impregnated sample is placed in a 100° C. oven to dry for 12 h, and then placed in a muffle furnace to calcine at 350° C. for 4 h to calcine and decompose the precursor salt to obtain a nickel-based macroporous silica gel catalyst, and the remaining steps are the same as in Example 1.

[0047] Comparative Example 1

[0048] A method for preparing a natural gas-steam reforming hydrogen production catalyst, comprising the following steps:

[0049] (1) A 5 mol / L aqueous solution of nickel nitrate was prepared as the impregnation solution, and the loading amount was 5 wt%.

[0050] (2) Weigh 25 g of commercial fumed silica as a carrier, impregnate the solution prepared in step (1) on the silica carrier, and dry it at 100°C.

[0051] (3) The calcination process is the same as in Example 1.

[0052] Performance Evaluation

[0053] The performance evaluation was carried out on a 30mL micro fixed bed reactor. 20g of the catalyst described in Examples 1-8 and Comparative Example 1 and 50mL of quartz sand were weighed and loaded into the middle section of the reactor. Porcelain balls or quartz wool were used to support both ends. 25% H2 / N2 was continuously introduced under programmed temperature, and the catalyst was reduced at 700°C for 2h. When the reaction gas was introduced, the feed ratio of raw methane to hydrogen was 1:1, and the reaction gas space velocity was 80L / g cat h, and the reaction temperature was 700°C. Sampling and analysis were performed 1 h after the reaction started to ensure that the reaction operation reached stability. The experimental results are shown in Table 1.

[0054] Table 1

[0055]

[0056] The catalyst prepared in Example 1 was used for evaluation of natural gas-steam reforming reaction, except that the ratio of the reaction gas was adjusted. The evaluation process was the same as above, and the experimental results are shown in Table 2.

[0057] Table 2

[0058]

[0059]

[0060] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a catalyst for hydrogen production by natural gas-steam reforming, characterized in that: The following steps are involved: S1. Preparation of macroporous silica carrier: The acid solution is dripped into water glass with a SiO2 solubility of 8-15%, or the water glass is dripped into the acid solution for acidification, the pH value of the acidification end point is controlled to be 6-8, and after stirring for 0.5-3h, an aging is performed at 60-90°C for 1-8h; then, sulfuric acid with a mass fraction of 8-15% is added to adjust the pH of the slurry to 1-3, and a secondary aging is performed at room temperature for 1-8h. The slurry is filtered, washed, and dried to obtain a macroporous silica gel carrier; S2. Nickel-based active component loading The macroporous silica gel carrier prepared in step S1 is immersed in a 1-10 mol / L nickel salt precursor solution, with a loading amount of 0.5-10 wt % based on Ni, and then dried and calcined to obtain a loaded nickel-based macroporous silica gel catalyst.

2. The method for preparing a natural gas-steam reforming hydrogen production catalyst according to claim 1, characterized in that: In step S1, a macroporous silica gel carrier is prepared by a parallel flow method, and the preparation method is as follows: desalted water is used as a base liquid, and water glass with a SiO2 solubility of 8-15% and an acid solution are added to the base liquid simultaneously using a diaphragm pump, and the pH of the neutralization process is controlled at 6-8 by adjusting the dripping speed of the acid solution and the silicon source; after the addition is completed, it is stirred for 0.5-4h and aged at 60-90°C for 1-8h; after one aging, the pH of the slurry is adjusted to 1-3 using sulfuric acid with a mass fraction of 8-15%, and aged at room temperature for 1-8h. The obtained slurry is filtered, washed, and dried to obtain a macroporous silica gel carrier.

3. The method for preparing a natural gas-steam reforming hydrogen production catalyst according to claim 1 or 2, characterized in that: In step S1, the acid solution is selected from sulfuric acid, formic acid, acetic acid, hydrochloric acid, nitric acid or phosphoric acid; the mass fraction of sulfuric acid is 5-20%, and the mass fraction of formic acid, acetic acid, hydrochloric acid, nitric acid and phosphoric acid is 8-15%.

4. The method for preparing a natural gas-steam reforming hydrogen production catalyst according to claim 1 or 2, characterized in that: In step S1, the slurry is filtered, washed with desalted water, and dried at 100-120° C. for 6-12 hours.

5. The method for preparing a natural gas-steam reforming hydrogen production catalyst according to claim 1 or 2, characterized in that: In step S2, the precursor nickel salt is selected from one of nickel nitrate, nickel oxalate, nickel acetate, and nickel formate, or a mixture of several of them.

6. The method for preparing a natural gas-steam reforming hydrogen production catalyst according to claim 1 or 2, characterized in that: In step S2, the impregnation liquid uses one or a mixture of water, ethanol and methanol as the solvent; nitric acid is added as an acidifying agent during the preparation of the impregnation liquid, and the volume ratio of nitric acid to the impregnation liquid is (1-10):

50.

7. The method for preparing a natural gas-steam reforming hydrogen production catalyst according to claim 1 or 2, characterized in that: In step S2, the drying process temperature is 80-120° C. and the drying time is 4-10 hours.

8. The method for preparing a natural gas-steam reforming hydrogen production catalyst according to claim 1 or 2, characterized in that: In step S2, the high temperature calcination process uses one or a mixture of air, oxygen, nitrogen, etc., the calcination temperature is 300-400° C., and the calcination time is 2-8 hours.

9. A natural gas-steam reforming hydrogen production catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the natural gas-steam reforming hydrogen production catalyst according to claim 9 in a reforming reaction of natural gas and steam.

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