Method for preparing hydrogen through catalytic cracking of CVI tail gas by using porous SiO2 loaded Ni

Abstract

The invention discloses a method for preparing hydrogen through catalytic cracking of CVI tail gas by using porous SiO2 loaded Ni. The CVI tail gas is used as reaction gas, and clean hydrogen energy is prepared through catalytic cracking. According to the method, tail gas waste heat is utilized, a catalytic cracking material is designed according to tail gas components, tail gas catalytic cracking deep dehydrogenation is achieved, hydrogen in tail gas is recycled, a new method is provided for carbon-based material chemical vapor deposition tail gas utilization, and green and environment-friendly production and development of the industry for preparing high-performance carbon-based materials through chemical vapor deposition are promoted.

Description

Technical Field

[0001] The invention relates to a method for preparing hydrogen by catalytically cracking CVI tail gas using porous SiO2 loaded Ni, and belongs to the technical field of material synthesis. Background Art

[0002] Chemical vapor deposition (CVI) is the main technical means for preparing high-performance carbon / carbon composite materials. Carbon / carbon composite materials are formed by pyrolysis carbon formed by natural pyrolysis of carbon-hydrogen (natural gas) carbon source gas in a pyrolysis furnace. The utilization rate of carbon-hydrogen gas in the preparation process of carbon / carbon materials is low, and the atomic utilization rate is only about 10%. The natural pyrolysis process temperature is usually higher than 1000°C. The pyrolysis furnace will discharge high-calorific value, high-temperature and low-pressure tail gas containing methane, hydrogen, nitrogen, small molecule olefin / alkyne gas and tar. In the development process of carbon material research and development → carbon material performance improvement → cost reduction and efficiency improvement, the carbon / carbon industry has focused on product improvement and production cost reduction, but has ignored the comprehensive utilization and environmental friendliness of pyrolysis tail gas. At present, it is mainly discharged by ignition, which increases carbon emissions and waste of valuable products. With the development of the industry, environmental and energy issues are related to the success or failure of enterprises, industry progress and national development. The comprehensive utilization of tail gas is imminent and needs to be solved urgently. Summary of the invention

[0003] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications and omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0004] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 loaded Ni, which can adjust the tail gas outlet parameters, maximize the atomic utilization rate, reduce energy consumption, and be suitable for large-scale production. In order to achieve the above purpose, the present invention provides the following technical solutions:

[0006] A method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 loaded Ni, the raw materials comprising: tetraethyl orthosilicate, ammonia water and ethanol; the preparation steps are as follows:

[0007] S1. First, stir anhydrous ethanol, deionized water and ammonia water to obtain a mixed solution A;

[0008] S2. Add ethyl orthosilicate to the mixed solution A and stir in a greenhouse for 3.5 to 4.5 hours; filter and wash with ethanol and water until neutral;

[0009] S3, drying the washed material at 105°C for 24h, transferring it to a crucible, and placing the crucible in a muffle furnace;

[0010] S4, setting the temperature of the muffle furnace at a high temperature and calcining for 1 to 5 hours to obtain porous spherical silica;

[0011] S5, dispersing porous spherical silica in water, adding one or more of ammonia water, sodium hydroxide or ammonium fluoride and stirring evenly; adding one or more of cerium nitrate or nickel nitrate; filtering and washing, vacuum drying after washing, and reducing in a hydrogen reduction furnace to obtain catalyst A;

[0012] S6. The CVI tail gas is introduced into a container with catalyst A to be cracked to obtain hydrogen.

[0013] As a preferred embodiment of the method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 loaded with Ni according to the present invention, the porous spherical silica has the characteristics of uniform size and controllable pore diameter; the sphere size of the porous spherical silica is 100-300nm.

[0014] As a preferred embodiment of the method for preparing hydrogen by catalytic cracking of CVI tail gas by porous SiO2 loaded Ni according to the present invention; in steps S1 and S2, tetraethyl orthosilicate: ammonia water = 1:1-10; tetraethyl orthosilicate: water = 1:1-10; tetraethyl orthosilicate: ammonia water = 1:1-10; tetraethyl orthosilicate: anhydrous ethanol = 1:50-100.

[0015] As a preferred embodiment of the method for preparing hydrogen by catalytic cracking of CVI tail gas with porous SiO2 supported Ni according to the present invention, the stirring rate in S2 is controlled at 1000-10000 Rap, and the reaction time is controlled at 2-24 h.

[0016] As a preferred embodiment of the method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 loaded Ni according to the present invention, the calcination temperature is controlled at 400-800°C.

[0017] As a preferred embodiment of the method for preparing hydrogen by catalytic cracking of CVI tail gas by porous SiO2 supported Ni according to the present invention, the step of obtaining the catalyst in step S5 is as follows:

[0018] S51, dispersing porous spherical silica in water, and ultrasonicating for 30-120 min;

[0019] S52, after the ultrasonic treatment, add one or more of ammonia water, sodium hydroxide or ammonium fluoride, and stir in a room temperature for 30 minutes;

[0020] S53, adding one or more of cerium nitrate or nickel nitrate, and stirring at room temperature for 50 min to 70 min;

[0021] S54, filter and wash with deionized water until neutral, vacuum dry and place in a hydrogen tube furnace for reduction; obtain catalyst A.

[0022] As a preferred embodiment of the method for preparing hydrogen by catalytic cracking of CVI tail gas by porous SiO2 loaded with Ni according to the present invention, the porous spherical silica: water = 1:50-500, ultrasonic treatment for 30-120 minutes, adding one or more of ammonia water, sodium hydroxide and ammonium fluoride, and controlling the concentration to 0.5-5%. Then, adding one or more of cerium nitrate and nickel nitrate, and controlling the concentration to 0.5-5%.

[0023] As a preferred embodiment of the method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 loaded Ni according to the present invention, the temperature of the hydrogen reduction furnace is controlled at 200-500° C., and the reduction time is controlled at 1-8 hours.

[0024] At the same time, the catalytic cracking of CVI tail gas, the tail gas inlet temperature is controlled at 500-800°C, and the catalyst filling amount is 50-500L / g according to the tail gas intake amount. Cat. / h.

[0025] Beneficial Effects

[0026] The present invention discloses a method for preparing hydrogen by catalytically cracking CVI tail gas using porous SiO2 loaded Ni. The method has simple technology, simple and efficient process, realizes the recovery and reuse of hydrogen in the tail gas, consumes less energy for waste heat recycling, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 The SEM image and macroscopic sample image of SiO2 in Example 1 are shown in FIG.

[0029] Figure 2 This is the SEM image after SiO2 etching in Example 1

[0030] Figure 3 The SEM image and macroscopic sample image of SiO2 loaded with nickel in Example 1 DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0033] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0034] A method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 loaded Ni, the raw materials comprising: tetraethyl orthosilicate, ammonia water and ethanol; the preparation steps are as follows:

[0035] S1. First, stir anhydrous ethanol, deionized water and ammonia water to obtain a mixed solution A;

[0036] S2. Add ethyl orthosilicate to the mixed solution A and stir in a greenhouse for 3.5 to 4.5 hours; filter and wash with ethanol and water until neutral;

[0037] S3, drying the washed material at 105°C for 24h, transferring it to a crucible, and placing the crucible in a muffle furnace;

[0038] S4, setting the temperature of the muffle furnace at a high temperature and calcining for 1 to 5 hours to obtain porous spherical silica;

[0039] S5, dispersing porous spherical silica in water, adding one or more of ammonia water, sodium hydroxide or ammonium fluoride and stirring evenly; adding one or more of cerium nitrate or nickel nitrate; filtering and washing, vacuum drying after washing, and reducing in a hydrogen reduction furnace to obtain catalyst A;

[0040] S6. The CVI tail gas is introduced into a container with catalyst A to be cracked to obtain hydrogen.

[0041] The porous spherical silica has the characteristics of uniform size and controllable pore diameter; the spherical size of the porous spherical silica is 100-300nm.

[0042] In steps S1 and S2, tetraethyl orthosilicate: ammonia water = 1:1-10; tetraethyl orthosilicate: water = 1:1-10; tetraethyl orthosilicate: ammonia water = 1:1-10; tetraethyl orthosilicate: anhydrous ethanol = 1:50-100.

[0043] The stirring rate in S2 is controlled at 1000-10000 Rap, and the reaction time is controlled at 2-24 h.

[0044] The calcination temperature is controlled at 400-800°C.

[0045] Step S5: The steps of obtaining the catalyst are:

[0046] S51, dispersing porous spherical silica in water, and ultrasonicating for 30-120 min;

[0047] S52, after the ultrasonic treatment, add one or more of ammonia water, sodium hydroxide or ammonium fluoride, and stir in a room temperature for 30 minutes;

[0048] S53, adding one or more of cerium nitrate or nickel nitrate, and stirring at room temperature for 50 min to 70 min;

[0049] S54, filter and wash with deionized water until neutral, vacuum dry and place in a hydrogen tube furnace for reduction; obtain catalyst A.

[0050] The porous spherical silica: water is 1:50-500 by mass ratio, ultrasonicated for 30-120 minutes, and one or more of ammonia water, sodium hydroxide and ammonium fluoride are added, and the concentration is controlled to be 0.5-5%. Then, one or more of cerium nitrate and nickel nitrate are added, and the concentration is controlled to be 0.5-5%.

[0051] The temperature of the hydrogen reduction furnace is controlled at 200-500° C., and the reduction time is controlled at 1-8 hours.

[0052] At the same time, the catalytic cracking of CVI tail gas, the tail gas inlet temperature is controlled at 500-800°C, and the catalyst filling amount is 50-500L / g according to the tail gas intake amount. Cat. / h.

[0053] Example 1

[0054] Add 20g of deionized water and 10g of ammonia water to 300g of anhydrous ethanol and stir evenly, then add 20g of tetraethyl silicate, stir at room temperature for 4h, control the stirring rate at 2000Rap, filter and wash, wash with ethanol and water until neutral, and dry at 105℃ for 24h. Transfer to a crucible, place in a muffle furnace, and calcine at 500℃ for 3h. Weigh 1g of the above powder, disperse in 100g of deionized water, ultrasonic for 60min, add 1g of sodium hydroxide and 0.5g of ammonium fluoride, stir at room temperature for 30min, then add 0.1g of cerium nitrate and 0.01g of nickel nitrate, stir at room temperature for 1h, filter and wash with deionized water until neutral, reduce in a hydrogen tubular furnace at 300℃ for 2h to obtain a catalyst.

[0055] The CVI tail gas inlet temperature is controlled at 700°C, and the catalyst filling amount is 100L / g according to the tail gas intake amount. Cat. / h, and the methane cracking rate is 97.5%.

[0056] Example 2

[0057] Add 20g of deionized water and 10g of ammonia water to 300g of anhydrous ethanol and stir evenly, then add 20g of tetraethyl silicate, stir at room temperature for 4h, control the stirring rate at 2000Rap, filter and wash, wash with ethanol and water until neutral, and dry at 105℃ for 24h. Transfer to a crucible, place in a muffle furnace, and calcine at 500℃ for 3h. Weigh 1g of the above powder, disperse in 100g of deionized water, ultrasonic for 60min, add 1g of ammonia water and 0.5g of ammonium fluoride, stir at room temperature for 30min, then add 0.1g of cerium nitrate and 0.1g of nickel nitrate, stir at room temperature for 1h, filter and wash with deionized water until neutral, reduce in a hydrogen tubular furnace at 300℃ for 2h to obtain a catalyst.

[0058] The CVI tail gas inlet temperature is controlled at 750°C, and the catalyst filling amount is 200L / g according to the tail gas intake amount. Cat. / h, and the methane cracking rate is 97.2%.

Claims

1. A method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 supported Ni, characterized in that: Ingredients include: Tetraethyl orthosilicate, ammonia water and ethanol; the preparation steps are as follows: S1. First, stir anhydrous ethanol, deionized water and ammonia water to obtain a mixed solution A; S2. Add ethyl orthosilicate to the mixed solution A and stir in a greenhouse for 3.5 to 4.5 hours; filter and wash with ethanol and water until neutral; S3, drying the washed material at 105°C for 24h, transferring it to a crucible, and placing the crucible in a muffle furnace; S4, setting the temperature of the muffle furnace at a high temperature and calcining for 1 to 5 hours to obtain porous spherical silica; S5, dispersing porous spherical silica in water, adding one or more of ammonia water, sodium hydroxide or ammonium fluoride and stirring evenly; adding one or more of cerium nitrate or nickel nitrate; filtering and washing, vacuum drying after washing, and reducing in a hydrogen reduction furnace to obtain catalyst A; S6. The CVI tail gas is introduced into a container with catalyst A to be cracked to obtain hydrogen.

2. A method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 loaded Ni according to claim 1; characterized in that: The porous spherical silica has the characteristics of uniform size and controllable pore diameter; the spherical size of the porous spherical silica is 100-300nm.

3. A method for preparing hydrogen by catalytic cracking of CVI tail gas by porous SiO2 supported Ni according to claim 1; characterized in that: In steps S1 and S2, tetraethyl orthosilicate: ammonia water = 1:1-10; tetraethyl orthosilicate: water = 1:1-10; tetraethyl orthosilicate: ammonia water = 1:1-10; tetraethyl orthosilicate: anhydrous ethanol = 1:50-100.

4. The method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 supported Ni according to claim 1, characterized in that: The stirring rate in S2 is controlled at 1000-10000 Rap, and the reaction time is controlled at 2-24 h.

5. The method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 supported Ni according to claim 1, characterized in that: The calcination temperature is controlled at 400-800°C.

6. The method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 supported Ni according to claim 1, characterized in that: Step S5: The steps of obtaining the catalyst are: S51, dispersing porous spherical silica in water, and ultrasonicating for 30-120 min; S52, after the ultrasonic treatment, add one or more of ammonia water, sodium hydroxide or ammonium fluoride, and stir in a room temperature for 30 minutes; S53, adding one or more of cerium nitrate or nickel nitrate, and stirring at room temperature for 50 min to 70 min; S54, filter and wash with deionized water until neutral, vacuum dry and place in a hydrogen tube furnace for reduction; obtain catalyst A.

7. The method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 supported Ni according to claim 6, characterized in that: , according to the mass ratio of the porous spherical silica: water = 1:50-500, ultrasonic for 30-120 minutes, add one or more of ammonia water, sodium hydroxide and ammonium fluoride, and control the concentration to 0.5-5%. Then add one or more of cerium nitrate and nickel nitrate, and control the concentration to 0.5-5%.

8. The method for preparing hydrogen by catalytic cracking of CVI tail gas using porous SiO2 supported Ni according to claim 6, characterized in that: The temperature of the hydrogen reduction furnace is controlled at 200-500° C., and the reduction time is controlled at 1-8 hours.

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