CN114534744B - A preparation method of solid acid catalyst based on aluminum smelting slag-green carbon-based dual carrier - Google Patents

Abstract

The invention discloses a method for preparing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual-carrier, comprising: activating aluminum smelting waste slag to obtain activated aluminum ash; heating biomass to Carbonize at 300-400°C for 10-20 hours to obtain a carbon-based matrix; mix the carbon-based matrix with concentrated sulfuric acid evenly, sulfonate at 100-300°C for 3-6 hours, cool, wash, and dry to obtain a carbon-based precursor; Mix the activated aluminum ash and the carbon-based precursor evenly, add 1,4-dioxane, immerse with ultrasonic assistance for 10-30 minutes, co-precipitate for 10-12 hours, filter, and take the residue, and store it at 105-120°C Dry the carbon-based material at a certain temperature to obtain the carbon-based material; place the carbon-based material in a constant-temperature horizontal tube furnace, raise the temperature to 400-600°C in a nitrogen atmosphere, and calcinate at a constant temperature for 2-3 hours to obtain aluminum smelting ash-green carbon-based Dual carrier solid acid catalyst. The catalyst exhibits high catalytic activity and stability, large specific surface area and spacious pore structure pore size.

Description

Preparation of a solid acid catalyst based on aluminum smelting slag-green carbon-based dual support method

technical field

The invention belongs to the technical field of catalyst preparation, and in particular relates to a preparation method of a solid acid catalyst based on aluminum smelting slag-green carbon-based dual carriers.

Background technique

With the increasing consumption of non-renewable energy such as coal, oil, and natural gas, the research, development and utilization of renewable energy have become a hot spot of widespread concern. Biomass energy is favored by people because of its low environmental hazards, abundant sources, convenient storage and transportation, and low cost. my country has a rich raw material supply of biomass energy. If these biomass resources are developed and utilized to the maximum extent, the current problems of resource shortage and environmental pollution can be effectively solved, and it is of great significance to achieve carbon peak carbon neutrality.

At present, the application technologies of biomass energy in my country include solidified molding fuel technology, liquid fuel technology, gas fuel technology, and power generation technology.

However, most of these utilization technologies of biomass resources will use various catalysts to promote the reaction process; therefore, one of the keys to the development of the biomass energy industry is to develop various catalysts to adapt to different raw materials processing requirements. Because of its large specific surface area, strong mechanical stability and thermal stability, Al ₂ O ₃ is widely used as a biomass pyrolysis gasification catalyst and carrier, and exhibits strong catalytic activity. The commonly used Al ₂ O ₃ catalyst is prepared from analytically pure reagents, which increases the reaction cost to a certain extent.

Contents of the invention

The purpose of this section is to outline some aspects of embodiments of the invention and briefly describe some preferred embodiments. Some simplifications or omissions may be made in this section, as well as in the abstract and titles of this application, to avoid obscuring the purpose of this section, the abstract and titles, and such simplifications or omissions should not be used to limit the scope of the invention.

In view of the problems mentioned above and/or in the prior art, the present invention is proposed.

Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual carrier.

In order to solve the above technical problems, the present invention provides the following technical solutions: a method for preparing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual carrier, comprising:

Activation treatment of aluminum smelting waste slag to obtain activated aluminum ash;

Heating the biomass to 300-400°C under a nitrogen atmosphere, and carbonizing it for 10-20 hours to obtain a carbon-based matrix;

Mix the carbon-based matrix with concentrated sulfuric acid evenly, sulfonate at 100-300°C for 3-6 hours, cool, wash with water, and dry to obtain the carbon-based precursor;

Mix the activated aluminum ash and the carbon-based precursor evenly, add 1,4-dioxane, immerse with ultrasonic assistance for 10-30 minutes, co-precipitate for 10-12 hours, filter, and take the residue, and store it at 105-120°C Dry at a certain temperature to obtain a carbon-based material;

Put the carbon-based material in a constant-temperature transverse tube furnace, raise the temperature to 400-600° C. under a nitrogen atmosphere, and calcinate at a constant temperature for 2-3 hours to obtain aluminum smelting slag-green carbon-based dual-support solid acid catalyst.

As a preferred solution of the method for preparing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual-support according to the present invention, wherein: the activation treatment of aluminum smelting waste slag includes,

Remove the light ash on the surface of aluminum smelting waste slag by medium-strong acid with a concentration of 1, 3, 5, and 7 mol/L in sequence, and obtain aluminum ash powder containing more than 99% Al ₂ O ₃ after roasting at 550-600°C;

After auxiliary activation of aluminum ash powder by 1-5mol/L weak acid, it is centrifuged at 2000r/min, baked at 500-700°C for 3-6 hours in an air atmosphere, and cooled naturally to room temperature to obtain activation. After aluminum ash.

As a preferred version of the method for preparing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual-support in the present invention, wherein: the medium strong acid includes sulfuric acid, nitric acid and phosphoric acid, and the weak acid includes acetic acid, hydrofluoric acid acid and phenol.

As a preferred solution of the preparation method of the aluminum smelting slag-green carbon-based dual-carrier based solid acid catalyst of the present invention, wherein: the auxiliary activation includes rotary evaporation, wherein the rotary evaporation time is 20-30 minutes.

As a preferred version of the method for preparing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual-carriers in the present invention, wherein: the biomass includes corn stalks, wood chips, rice husks and peanut shells, and its particle size is The size is 10-20um.

As a preferred version of the method for preparing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual-carriers in the present invention, wherein: the carbon-based substrate and concentrated sulfuric acid are uniformly mixed, wherein the carbon-based substrate and concentrated sulfuric acid The volume ratio of sulfuric acid is 10:1-3, and the mass fraction of concentrated sulfuric acid is 80-90%.

As a preferred version of the method for preparing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual-carriers in the present invention, wherein: after mixing the activated aluminum ash and carbon-based precursor evenly, add 1 , 4-dioxane, wherein the mass ratio of the activated aluminum ash to the carbon-based precursor is 1:1 to 2, 1,4-dioxane to the activated aluminum ash and the carbon-based precursor The sum of the masses is 4:10 in terms of the volume-to-mass ratio g:mL.

As a preferred solution of the preparation method of the aluminum smelting slag-green carbon-based dual-carrier based solid acid catalyst of the present invention, wherein: the ultrasonic-assisted impregnation is 10-30 min, wherein the ultrasonic power is 80W.

As a preferred scheme of the preparation method of the solid acid catalyst based on aluminum smelting slag-green carbon-based dual-support in the present invention, wherein: the temperature is raised to 400-600° C. under a nitrogen atmosphere, and the heating rate is 20 °C/min.

Another object of the present invention is to overcome the deficiencies in the prior art and provide a product based on the preparation method of the aluminum smelting slag-green carbon-based dual carrier solid acid catalyst, the specific surface area of the product is 216～ 352m ² /g, pore diameter 10-15nm.

Beneficial effects of the present invention:

(1) The present invention proposes a method for synthesizing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual carriers, in particular to a method for directional conversion of biomass tar into hydrogen-rich gas based on aluminum smelting slag-green carbon A dual-carrier-based solid acid catalyst synthesis method uses the waste aluminum smelting slag after activation as a carrier, and uses green biomass as a matrix after carbonization and sulfonation, which provides a new path for the preparation of catalysts used in the biomass field.

(2) The catalyst preparation process of the present invention is guaranteed to be carried out at relatively low temperature and normal pressure, avoiding the unsafe problem caused by high temperature and high pressure; at the same time, different auxiliary methods are used to perform directional selectivity and ion exchange of active components on aluminum smelting slag It ensures that the active groups in the aluminum smelting slag fully contact with the carbon-based precursor during the subsequent co-precipitation, and the catalyst shows high catalytic activity and stability, and a large specific surface area (216-352m ² /g) And spacious pore structure pore size (pore diameter 10-15nm).

(3) The preparation cost of the catalyst of the present invention is relatively low, and the process is simple.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort. in:

Figure 1 is a diagram of the catalyst prepared in Example 2 of the present invention.

detailed description

In order to make the above objects, features and advantages of the present invention more obvious and comprehensible, the specific implementation manners of the present invention will be described in detail below in conjunction with the embodiments of the specification.

In the following description, a lot of specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, and those skilled in the art can do it without departing from the meaning of the present invention. By analogy, the present invention is therefore not limited to the specific examples disclosed below.

Second, "one embodiment" or "an embodiment" referred to herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. "In one embodiment" appearing in different places in this specification does not all refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

Example 1

This example provides a method for preparing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual carrier, the main steps are:

(1) Use 1 mol/L of sulfuric acid to remove the light ash on the surface of the aluminum smelting waste residue and obtain aluminum ash powder after roasting at 600°C;

The obtained aluminum ash powder is assisted by rotary evaporation using 1mol/L acetic acid;

The weak acid-treated aluminum ash solution was centrifuged at 2000r/min to achieve complete exchange of metal ions, then baked at a constant temperature and high temperature at 500°C for 3 hours in an air atmosphere, cooled naturally to room temperature, and stored for later use.

(2) Biomass corn stalks were heated to 300°C under a nitrogen atmosphere (flow rate 50ml/min), and carbonized for 10 hours to obtain a carbon-based matrix;

Mix the obtained carbon-based matrix with concentrated sulfuric acid at a mass volume ratio of 10:1, sulfonate in a constant temperature oil bath at 150°C for 3 hours, cool, and wash with deionized water until there is no SO ₄ ^2- in the filtrate. Drying at a temperature of ℃ is the carbon-based precursor.

(3) After the activated aluminum ash and the obtained carbon-based precursor were mixed uniformly at a ratio of 1:1, they were dissolved with 1,4-dioxane at a mass volume ratio of 4:10 and fully stirred. After soaking for 10 minutes, co-precipitate for 12 hours and filter with a sand core funnel to obtain the filtrate and residue, keep the residue, and dry at 105°C;

Then, place it in a constant-temperature transverse tube furnace, raise the heating rate of 20°C/min to 600°C for 3 hours in a nitrogen atmosphere, and calcinate at a constant temperature for 3 hours to obtain aluminum smelting slag with a specific surface area of 216m ² /g and a channel diameter of 10nm- Green carbon-based dual-support solid acid catalyst.

Example 2

This example provides a method for preparing a solid acid catalyst based on aluminum smelting slag-green carbon-based dual carrier, the main steps are:

(1) Use 1 mol/L sulfuric acid to remove the light ash on the surface of aluminum smelting waste slag, and then roast at 600°C to obtain aluminum ash powder; use 1 mol/L acetic acid for rotary evaporation to assist activation of the obtained aluminum ash powder;

The weak acid-treated aluminum ash solution was centrifuged at 2000r/min to achieve complete exchange of metal ions, then baked at a constant temperature and high temperature at 600°C for 3 hours in an air atmosphere, cooled naturally to room temperature, and stored for later use.

(2) Biomass corn stalks were heated to 380°C in a nitrogen atmosphere (flow rate 50ml/min), and carbonized for 10 hours to obtain a carbon-based matrix;

Mix the obtained carbon-based matrix with concentrated sulfuric acid at a mass volume ratio of 10:2, sulfonate in a constant temperature oil bath at 150°C for 3 hours, cool, and wash with deionized water until there is no SO ₄ ^2- in the filtrate. Drying at a certain temperature is a carbon-based precursor.

(3) After the activated aluminum ash and the obtained carbon-based precursor were mixed uniformly at a ratio of 1:1, they were dissolved with 1,4-dioxane at a mass volume ratio of 4:10 and fully stirred. After soaking for 20 minutes, co-precipitate for 12 hours and filter with a sand core funnel to obtain the filtrate and residue, keep the residue and dry it at 105°C;

Then, place it in a constant-temperature transverse tube furnace, raise the heating rate of 20°C/min to 600°C for 3 hours in a nitrogen atmosphere, and calcinate at a constant temperature for 3 hours to obtain aluminum smelting slag with a specific surface area of 352m ² /g and a pore diameter of 15nm- Green carbon-based dual-support solid acid catalyst.

The diagram of the prepared catalyst is shown in Figure 1.

Example 3

Under the conditions of Example 2, the effect of the mass ratio of the activated aluminum ash to the obtained carbon-based precursor on the performance of the prepared catalyst was explored. Other conditions were the same as in Example 2. The conditions and results are shown in Table 1.

Table 1

It can be seen from Table 1 that the optimal mixing ratio of aluminum ash and carbon-based precursor is 1:1, too much carbon-based material will affect the mechanical strength of the catalyst, and adding too much aluminum ash will affect the pore structure of the catalyst and specific surface area.

Example 4

The activated aluminum ash obtained in Example 2 was applied to catalyze the pyrolysis of biomass tar, and the conversion rate was 70.5%;

Biomass corn stalks were heated to 380°C in a nitrogen atmosphere (flow rate 50ml/min), and carbonized for 10 hours to obtain a carbon-based matrix; the obtained carbon-based matrix was mixed with concentrated sulfuric acid at a mass-to-volume ratio of 10:2, and placed in a constant temperature oil bath Sulfonate at 150°C for 3h, cool, wash with deionized water until there is no SO ₄ ^2- in the filtrate, and dry at 105°C to obtain a carbon-based precursor. Place it in a constant temperature transverse tube furnace under nitrogen Under the atmosphere, the heating rate was increased to 600°C for 3 hours at a constant temperature of 20°C/min to obtain a biomass catalyst, which was used to catalyze the pyrolysis of biomass tar, and the conversion rate was 76.4%;

Table 2

Activated Aluminum Ash Biomass catalyst Catalytic biomass tar pyrolysis conversion rate (%) 70.5 76.4

As a by-product of biomass pyrolysis, biochar has a rich pore structure and a large specific surface area, which can well adsorb light tar compounds, and as a catalyst carrier, it has a good catalytic effect on the removal of biomass tar. At the same time, it can be seen that the activated aluminum ash and biochar in the present invention have a synergistic catalytic effect.

Example 5

Under the conditions of Example 2, explore the influence of different solvents on the catalyst, other process conditions are the same as Example 2, and the results are shown in Table 3.

table 3

solvent water ethanol Acetic acid 1,4-dioxane Catalytic biomass tar pyrolysis conversion rate (%) 85.2 86.7 92.9 98.1

It can be seen that the biomass carbon carrier and aluminum smelting ash have good dispersion in 1,4-dioxane, which can ensure the full contact between the active component and the carrier. Here, water, ethanol, acetic acid, etc. are also used as solvents, whose dispersibility and solubility are not as good as 1,4-dioxane.

Example 6

Under the conditions of Example 2, the influence of the calcination temperature of different aluminum smelting slag-green carbon-based dual-support solid acid catalysts on the catalyst was explored, and the results are shown in Table 4.

Table 4

Calcination temperature 400 500 600 800 Catalytic biomass tar pyrolysis conversion rate (%) 89.3 94.4 98.1 92.4

It can be seen that, compared with 400 and 500°C, after calcining at 600°C, the mechanical strength of the catalyst is higher, the binding force of the two materials is stronger, and the catalytic effect is the best. If the temperature is too high, its performance will decrease instead.

It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation, although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (7)

1. A preparation method based on aluminum smelting slag-green carbon-based dual-carrier solid acid catalyst for directional conversion of biomass tar into hydrogen-rich gas, characterized in that: comprising, Activation treatment of aluminum smelting waste slag: the light ash on the surface of aluminum smelting waste slag is removed by medium-strong acid with a concentration of 1, 3, 5, and 7 mol/L in sequence, and after roasting at 550~600°C, the aluminum smelting waste slag containing more than 99% Al ₂ O ₃ is obtained. Aluminum ash powder; After the aluminum ash powder is activated by 1~5 mol/L weak acid, it is centrifuged at 2000r/min, baked at 500~700℃ for 3~6h in an air atmosphere, and cooled naturally to room temperature. Aluminum ash after activation; Wherein, described auxiliary activation comprises rotary evaporation, and rotary evaporation time is 20～30min; Heating the biomass to 300-400°C under a nitrogen atmosphere, and carbonizing it for 10-20 hours to obtain a carbon-based matrix; Mix the carbon-based matrix with concentrated sulfuric acid evenly, sulfonate at 100-300°C for 3-6 hours, cool, wash with water, and dry to obtain the carbon-based precursor; Mix the activated aluminum ash and the carbon-based precursor evenly, add 1,4-dioxane, impregnate with ultrasonic assistance for 10-30 minutes, co-precipitate for 10-12 hours, filter, and take the residue, Drying at a certain temperature, the carbon-based material is obtained, wherein the mass ratio of the activated aluminum ash to the carbon-based precursor is 1:1~2; Put the carbon-based material in a constant-temperature transverse tube furnace, raise the temperature to 400-600°C in a nitrogen atmosphere, and calcine at a constant temperature for 2-3 hours to obtain aluminum smelting slag-green carbon-based dual-support solid acid catalyst. 2. The preparation method according to claim 1, characterized in that: the medium strong acid comprises sulfuric acid, nitric acid and phosphoric acid, and the weak acid comprises acetic acid, hydrofluoric acid and phenol. 3. The preparation method according to claim 1, characterized in that: the biomass includes corn stalks, sawdust, rice husks and peanut husks, and its particle size is 10-20um. 4. preparation method as claimed in claim 1, is characterized in that: described carbon-based matrix and vitriol oil are mixed uniformly, and wherein, carbon-based matrix and vitriol oil volume ratio are 10:1～3, and the concentrated sulfuric acid mass fraction is 80~90%. 5. The preparation method according to claim 1, characterized in that: the ultrasonic-assisted impregnation is 10-30 min, wherein the ultrasonic power is 80W. 6 . The preparation method according to claim 1 , characterized in that: the temperature is raised to 400-600° C. under a nitrogen atmosphere, wherein the heating rate is 20° C./min. 7. The product prepared by the preparation method according to any one of claims 1-6, characterized in that: the specific surface area of the product is 216-352 m ² /g, and the pore diameter is 10-15 nm.

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