WO2021022848A1

WO2021022848A1 - Monolithic catalyst preparation method employing 3d printing, and application of monolithic catalyst

Info

Publication number: WO2021022848A1
Application number: PCT/CN2020/087576
Authority: WO
Inventors: 朱文帅; 朱捷; 吴沛文; 巢艳红; 何静; 邓畅; 陆林杰; 李华明
Original assignee: 江苏大学
Priority date: 2019-08-05
Filing date: 2020-04-28
Publication date: 2021-02-11
Also published as: GB2600900A; GB2600900B; CN110479331A; GB202202504D0

Abstract

A monolithic catalyst preparation method employing 3D printing, and an application of a monolithic catalyst in oxidative desulfurization of fuel oil. The method comprises: printing a three-dimensional model using a light-curing printer, and then performing carbonization at a high temperature; and loading a formed three-dimensional carbide with phosphotungstic acid so as to prepare and obtain a monolithic catalyst for deep oxidative desulfurization by means of 3D printing. The prepared catalyst can be easily separated from oil after the reaction has ended, and the operation is simple. Moreover, the catalyst facilitates the removal of sulfides such as DBT, 4-MDBT, and 4,6-DMDBT from model oil, and provides good catalytic performance and cycle performance.

Description

Preparation method and application of 3D printed integral catalyst

Technical field

The invention belongs to the field of preparation of catalytic materials, and specifically refers to a preparation method of a 3D printed integral catalyst and its application in fuel oxidative desulfurization.

Background technique

SO _X emissions from the combustion of sulfide in fuel oil have become one of the main sources of environmental pollution. As environmental issues become increasingly prominent, the requirements for sulfur compounds in fuel have become more stringent. Industrially, sulfur compounds in fuel oil are usually removed by hydrodesulfurization (HDS), but hydrodesulfurization needs to be achieved under high reaction temperature and operating pressure. However, hydrodesulfurization has poor activity on aromatic sulfur compounds, and the HDS process requires more severe reaction conditions to achieve deep desulfurization. Therefore, many new desulfurization technologies, such as extractive desulfurization (EDS), adsorption desulfurization (ADS), and oxidative desulfurization (ODS), have been extensively studied. Among these methods, ODS has high activity to aromatic sulfur compounds under mild conditions and is considered a promising desulfurization method.

As an emerging manufacturing strategy, 3D printing technology has attracted more and more attention worldwide. Using 3D printing technology, it is possible to easily realize the molding of catalysts with different structures, especially those with complex structures, in a few steps. In addition, the use of 3D printing technology can significantly increase the utilization rate of raw materials.

At present, there is no relevant report on the technology of combining 3D printing and oxidative desulfurization to prepare catalysts.

Summary of the invention

The invention adopts 3D printing to directly generate the integral catalyst, which makes the separation of the catalyst and the reaction system easier. The use of 3D printing technology to build an overall catalyst can overcome the shortcomings of traditional powder catalysts, so that 3D printing technology has more application prospects in fuel oxidative desulfurization.

The invention provides a 3D printed monolithic catalyst and a preparation method and application thereof.

In order to achieve the above objective, the present invention provides a method for preparing a 3D printed monolithic catalyst, which includes the following steps:

(1) Design a three-dimensional model with a macroporous structure through 3Ds Max software, and print the designed three-dimensional model with a light-curing 3D printer;

(2) Place the printed three-dimensional model in a temperature-programmed tube furnace, under the protection of inert gas, heat to a certain temperature for calcination, and naturally cool to room temperature to obtain a carbonized three-dimensional carbide;

(3) Dissolve a certain amount of phosphotungstic acid in ethanol, add the three-dimensional carbide prepared in step (2) into the reaction flask, magnetically stir, remove the ethanol solution by thermal evaporation after immersion, and dry in an oven to obtain a catalyst.

In step (1), the raw material of the 3D printer is light-curable resin, and its main component is acrylic polymer.

In step (1), the three-dimensional model printed by the 3D printer is a multi-channel, hollow, white transparent three-dimensional model.

In step (2), the inert gas is nitrogen.

In step (2), the calcination temperature is 800-900°C and kept for 2 hours; the programmed temperature rise rate is 0.5°C/min.

In step (3), the loading amount of phosphotungstic acid in the catalyst is 1%-10%, and the magnetic stirring time is 24 hours.

The 3D printed monolithic catalyst obtained by the above method has a three-dimensional structure of porous channels.

The above-mentioned 3D printed monolithic catalyst can be used for the removal of sulfide in fuel.

The application of the above-mentioned 3D printing monolithic catalyst in the desulfurization of oxidized fuel oil, the specific application method is to add 3D printing monolithic catalyst, H ₂ O ₂ aqueous solution and glacial acetic acid to the fuel under magnetic stirring conditions to react, and simply filter the catalyst after the reaction is completed The separation of fuel and catalyst can be achieved.

The fuel includes DBT model oil, 4-MDBT model oil and 4,6-DMDBT model oil, among which the DBT model oil has the best desulfurization effect.

When the desulfurization reaction temperature is 70°C, the desulfurization effect is the best.

When the loading amount of phosphotungstic acid in the catalyst is 7%, the desulfurization effect is the best.

When the molar ratio of sulfide to H ₂ O ₂ in the fuel is 1:8, the desulfurization effect is the best.

The oxidation reaction conditions of the present invention are mild, and the reaction is carried out at normal temperature and normal pressure.

The invention provides a method for preparing a novel 3D printing monolithic catalyst. The catalyst can efficiently remove sulfide in fuel oil, is easy to operate and separate, and can be recycled. The preparation method is simple and the cost is low.

The invention has the following advantages:

1. By supporting high-activity phosphotungstic acid, the 3D printing overall catalyst has a good desulfurization effect, and the purpose of reducing the amount of catalyst is realized.

2. The obtained 3D printed monolithic catalyst can achieve the effects of simple operation, easy separation and recovery.

Description of the drawings

In Fig. 1, (a) is the 3Ds Max design drawing of Example 1, (b) is the 3D printed three-dimensional model optical photo, (c) is the three-dimensional carbide optical photo, and (d) is the 3D printed overall catalyst optical photo.

Figure 2 is the FT-IR diagram of the prepared 3D printed monolithic catalyst.

Figure 3 is an XRD pattern of the prepared 3D printed monolithic catalyst.

4 is a graph showing the catalytic activity of the 3D printed monolithic catalyst prepared in Example 1 on different sulfides in model oil.

5 is a graph showing the five-cycle activity of the 3D printed monolithic catalyst prepared in Example 1 on DBT sulfide in model oil.

detailed description

The preparation of the 3D printing monolithic catalyst and its effect on fuel desulfurization will be specifically described below with reference to the examples. The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination between the specific embodiments.

The preparation method of a 3D printed monolithic catalyst described in this embodiment is specifically carried out according to the following steps:

(1) Design a three-dimensional model through 3Ds Max software, and print the designed three-dimensional model with a light-curing 3D printer.

(2) Place the 3D printed three-dimensional model in a temperature programmed tube furnace, in a nitrogen atmosphere, heat up to 800°C-900°C at 0.5°C/min and keep it for 2 hours, and naturally cool to room temperature to obtain carbonized three-dimensional carbides.

(3) Dissolve a certain amount of phosphotungstic acid in ethanol, add the three-dimensional carbide to the reaction flask, and magnetically stir for 24 hours. After immersion, the ethanol solution is removed by thermal evaporation, and the resulting catalyst is dried in an oven.

The following are the fuel types used in the examples:

(1) DBT model oil is a model oil with a sulfur content of 200 ppm by dissolving dibenzothiophene (DBT) in dodecane.

(2) 4-MDBT model oil is a model oil with a sulfur content of 200ppm by dissolving 4-methyldibenzothiophene (4-MDBT) in dodecane.

(3) 4,6-DMDBT model oil is a model oil with a sulfur content of 200ppm by dissolving 4-methyldibenzothiophene (4,6-DMDBT) in dodecane.

Add oil to the double-necked bottle, add catalyst, glacial acetic acid and H ₂ O ₂ to the oil, and stir the reaction at a set temperature. After the reaction, the catalyst and oil can be separated by simple filtration. During the reaction Detect the content of sulfide in the oil by gas chromatography (GC-FID) and calculate the desulfurization rate:

In the following examples, the preparation method of the 3D printed monolithic catalyst is as follows:

Example 1:

(1) Design a three-dimensional sphere model with a diameter of 1cm through 3Ds Max software, and print the designed three-dimensional model with a light-curing 3D printer.

(2) Place the 3D printed three-dimensional model in a temperature-programmed tube furnace, in a nitrogen atmosphere, heat up to 900°C at 0.5°C/min and keep it for 2 hours, and cool to room temperature to obtain carbonized three-dimensional carbides.

(3) Dissolve a certain amount of phosphotungstic acid in ethanol, add the three-dimensional carbide to the reaction flask, and magnetically stir for 24 hours. After immersion, the ethanol solution was removed by thermal evaporation and dried in an oven to prepare a catalyst with a diameter of 0.5 cm.

Example 2:

(1) Design a three-dimensional sphere model through 3Ds Max software, and print the designed three-dimensional model with a light-curing 3D printer.

(2) Place the 3D printed three-dimensional model in a temperature-programmed tube furnace, in a nitrogen atmosphere, increase the temperature to 850°C at 0.5°C/min and keep it for 2 hours, and naturally cool to room temperature to obtain carbonized three-dimensional carbides.

Example 3:

(2) Place the 3D printed three-dimensional model in a temperature-programmed tube furnace, in a nitrogen atmosphere, increase the temperature to 800°C at 0.5°C/min and keep it for 2 hours, and naturally cool to room temperature to obtain carbonized three-dimensional carbides.

Desulfurization test 1:

Add 5mL DBT model oil to the double-necked bottle, add 5 3D printed monolithic catalysts (about 0.020g) obtained in Example 1, 1mL glacial acetic acid and 30wt.%.H ₂ O ₂ into the model oil, and the sulfide in the fuel is mixed with The molar ratio of hydrogen peroxide is 1:8 (the oxygen-sulfur ratio is 8), and the reaction is magnetically stirred under a constant temperature water bath environment of 70°C, while tap water is used to condense and reflux. During the reaction, samples were taken at regular intervals, and the sulfur content was detected by gas chromatography to calculate the desulfurization rate. The 3D printed monolithic catalyst prepared in Example 1 has a desulfurization rate of 100% for the sulfide DBT in the model oil within 150 minutes.

Desulfurization test 2:

Add 5mL 4-MDBT model oil to the double-necked bottle, add 5 3D printed monolithic catalysts (about 0.020g) obtained in Example 1, 1mL glacial acetic acid and 30wt.%.H ₂ O ₂ into the model oil, and sulfide in the fuel The molar ratio of the substance to the hydrogen peroxide is 1:8 (the oxygen-sulfur ratio is 8), the reaction is magnetically stirred under a constant temperature water bath environment of 70°C, and tap water is used to condense and reflux. During the reaction, samples were taken at regular intervals, and the sulfur content was detected by gas chromatography to calculate the desulfurization rate. The 3D printed monolithic catalyst prepared in Example 1 has a desulfurization rate of 100% for the sulfide 4-MDBT in the model oil within 150 minutes.

Desulfurization test 3:

Add 5mL 4,6-DMDBT model oil into the double-necked bottle, add 5 3D printed monolithic catalysts (about 0.020g) obtained in Example 1, 1mL glacial acetic acid and 30wt.%.H ₂ O ₂ into model oil, fuel The molar ratio of sulfide to hydrogen peroxide is 1:8 (the oxygen-sulfur ratio is 8), and the reaction is magnetically stirred under a constant temperature water bath environment of 70°C, while tap water is used to condense and reflux. During the reaction, samples were taken at regular intervals, and the sulfur content was detected by gas chromatography to calculate the desulfurization rate. The 3D printed monolithic catalyst prepared in Example 1 has a desulfurization rate of 100% for the sulfide 4,6-DMDBT in the model oil within 150 minutes.

In Figure 1, (a) is the 3Ds Max design drawing of the resulting 3D printed overall catalyst, (b) is the 3D printed three-dimensional model optical photo, (c) is the three-dimensional carbide optical photo, (d) is the 3D printed overall catalyst optical photo . It can be seen from the figure that the 3D printing model is a transparent porous three-dimensional model, the three-dimensional carbide is a silver-grey, metallic-lustrous porous three-dimensional model, and the 3D printing overall catalyst is a black porous three-dimensional model.

Figure 2 is a Fourier infrared image (FT-IR) of the 3D printed monolithic catalyst. In the FT-IR spectrum ^{^{^{1076cm -1, 978cm -1, 890cm -1}}} , 800cm -1 appeared typical characteristic peaks phosphotungstic acid Keggin structure.

Figure 3 is an X-ray diffraction pattern (XRD) of the 3D printed monolithic catalyst. The XRD pattern clearly shows the characteristic diffraction peaks of phosphotungstic acid at 2θ=10.3°, 20.7°, 23.1°, 25.4° and 29.5°.

4 is a graph showing the catalytic activity of the 3D printed monolithic catalyst prepared in Example 1 on different sulfides in model oil. It can be seen from the picture that the catalyst has a good removal effect on all three sulfides.

5 is a graph showing the five-cycle activity of the 3D printed monolithic catalyst prepared in Example 1 on DBT sulfide in model oil. It can be seen from the figure that the 3D printed overall catalyst has high stability and can still maintain high activity after five cycles.

Claims

A method for preparing a 3D printed monolithic catalyst is characterized in that it comprises the following steps:

(1) Design a three-dimensional model with a large hole structure through 3Ds Max software, and print the designed three-dimensional model with a light-curing 3D printer;

(2) Place the printed three-dimensional model in a temperature-programmed tube furnace, under the protection of inert gas, heat to a certain temperature for calcination, and naturally cool to room temperature to obtain a carbonized three-dimensional carbide;

(3) Dissolve a certain amount of phosphotungstic acid in ethanol, add the three-dimensional carbide prepared in step (2) into the reaction flask, magnetically stir, remove the ethanol solution by thermal evaporation after immersion, and dry in an oven to obtain a catalyst.
The preparation method according to claim 1, wherein in step (1), the 3D printing raw material is a light-curable resin, and its main component is an acrylic polymer.
The preparation method according to claim 1, wherein in step (1), the three-dimensional model printed by the 3D printer is a multi-hole, hollow, white transparent three-dimensional model.
The preparation method according to claim 1, wherein in step (2), in the temperature-programmed tube furnace, the inert gas is nitrogen.
The preparation method according to claim 1, wherein in step (2), the programmed temperature rise rate is 0.5° C./min, the calcination temperature is 800 to 900° C., and the temperature is maintained for 2 hours.
The preparation method according to claim 1, wherein in step (3), the loading amount of phosphotungstic acid in the catalyst is 1%-10%, and the magnetic stirring time is 24 hours.
A 3D printed monolithic catalyst, characterized in that it is prepared by the preparation method of any one of claims 1 to 6, and the catalyst has a porous three-dimensional structure.
The use of a 3D printed monolithic catalyst according to claim 7 for the removal of sulfide in fuel.