A method of mechanically-chemically pre-treating to induce low-temperature hydrocarbon refining of carbonates

Abstract

The application discloses a method for inducing low-temperature hydrorefining of carbonates by mechanical chemical pretreatment. The method is specifically operated as follows: carbonate powder and grinding balls are loaded into a ball mill tank for ball milling under normal temperature and pressure air condition; and after mechanical chemical treatment for 2-16 hours, completely amorphous carbonates are obtained; and then the treated carbonates are pyrolyzed at 450-550 DEG C in a pure hydrogen atmosphere, so that metal oxides and synthesis gas without CO2 are prepared. The long-range ordered crystal structure of the carbonates is amorphized and in-situ modulated by the mechanical chemical method, which is favorable for reducing the energy barrier of the carbonates hydrogenation reaction, improving the self-catalytic reaction efficiency, reducing the reaction temperature and the required time, realizing complete inhibition of CO2 generation at low temperature, effectively reducing the CO2 emission in the process, and simultaneously obtaining high-purity synthesis gas without CO2 and high-purity metal oxide products.

Description

Technical Field

[0001] This invention belongs to the field of clean energy technology, specifically relating to a method for low-temperature hydrogenation refining of carbonates induced by mechanochemical pretreatment. Background Technology

[0002] With industrial development, industries such as cement, steel, refractory materials, and calcium carbide in my country all involve high-temperature pyrolysis of carbonates. These processes account for over 50% of the total CO2 emissions from industry nationwide, causing irreversible impacts on the global climate. Furthermore, the high-temperature pyrolysis process consumes a significant amount of energy. Therefore, reducing CO2 emissions from these industrial processes while lowering the temperature of carbonate pyrolysis remains a major challenge. In-situ hydrogenation of carbonates is a promising method to further reduce CO2 emissions and energy consumption during pyrolysis, allowing for a simultaneous reduction in both reaction temperature and CO2 emissions.

[0003] Inorganic carbonates, as the solid form of CO2, are abundant in nature. Therefore, the reaction process of directly utilizing carbonates as a carbon source to prepare high-value-added chemical products has attracted widespread attention. The syngas and metal oxides produced by carbonate hydrogenation have wide applications. Syngas is widely used in many carbon chemical reactions, such as Fischer-Tropsch synthesis, formylation, and carbonylation. Metal oxides are also important raw materials for chemical production. For example, calcium oxide is the source of quicklime in industrial production and can be used to make cement; iron oxide can be used to make red pigments; and magnesium oxide can be used in high-grade lubricant processing, food additives, magnesium cement, etc. Metal oxides are widely used in building materials, municipal engineering, agriculture, machinery, and other fields. Therefore, the demand for metal oxides and syngas in the chemical industry is constantly increasing. The in-situ hydrogenation of carbonates to produce syngas and metal oxides has high application prospects. Summary of the Invention

[0004] The purpose of this invention is to provide a method for low-temperature hydrogenation refining of carbonates induced by mechanochemical pretreatment.

[0005] The method for low-temperature hydrogenation refining of carbonates induced by mechanochemical pretreatment is as follows: under normal temperature and pressure air conditions, carbonate powder and grinding balls are loaded into a ball mill jar for ball milling. After mechanochemical treatment for 2-16 hours, completely amorphous carbonates are obtained. Then, the treated carbonates are thermally decomposed at 450-550℃ in a pure hydrogen atmosphere, while metal oxides and synthesis gas without CO2 are prepared.

[0006] The carbonate is one or more of calcium carbonate, magnesium carbonate, iron carbonate, and copper carbonate.

[0007] The carbonate is a carbonate mineral. The carbonate mineral is calcite or magnesite.

[0008] The grinding balls are made of zirconium dioxide.

[0009] The ball mill rotates at a speed of 300-500 rpm, preferably 400 rpm.

[0010] The mass ratio of the grinding ball to the carbonate is 20-10:1, preferably 10:1.

[0011] The grinding balls are divided into three types: large balls, medium balls, and small balls. The mass ratio of the large balls, medium balls, and small balls is 4-6:2-4:1-3, preferably 5:3:2.

[0012] The large sphere has a diameter of 15-25mm, the medium sphere has a diameter of 5-8mm, and the small sphere has a diameter of 1-3mm.

[0013] During ball milling, carbonates clump together and need to be crushed before continuing ball milling.

[0014] The mechanochemical pretreatment time is 10 hours.

[0015] The flow rate of the pure hydrogen is 50-150 mL / min.

[0016] Carbonate hydrogenation is an autocatalytic reaction process involving the dissociation of hydrogen on the surface of carbonates and products, as well as the breaking of chemical bonds and lattice disruption within the carbonate. This invention utilizes a mechanochemical method to amorphize and in-situ modulate the long-range ordered crystal structure of carbonates, which helps to lower the energy barrier of the carbonate hydrogenation reaction, improve the efficiency of the autocatalytic reaction, reduce the reaction temperature and time, and achieve complete suppression of CO2 generation at low temperatures, effectively reducing CO2 emissions. Simultaneously, it yields high-purity syngas and high-purity metal oxide products free of CO2. The production process of this invention is simple, requires no catalysts or additives, has mild reaction conditions, high yield, good selectivity, saves costs associated with heating and gas separation and purification, and produces high-value-added products with significant practical application value. Attached Figure Description

[0017] Figure 1 This is the XRD pattern of calcium carbonate before complete mechanochemical treatment in Example 1.

[0018] Figure 2 This is the XRD pattern of amorphous calcium carbonate after complete mechanochemical treatment in Example 1.

[0019] Figure 3 This is a TEM image of calcium carbonate with intact crystal structure before mechanochemical treatment in Example 1.

[0020] Figure 4 This is a TEM image of amorphous calcium carbonate with disrupted crystal structure after mechanochemical treatment in Example 1.

[0021] Figure 5 This is a temperature-programmed decomposition diagram of amorphous calcium carbonate obtained by different mechanochemical treatment times in Example 1.

[0022] Figure 6 yes Figure 5 A graph showing the temperature variation at the highest point during the decomposition of amorphous calcium carbonate under different mechanical and chemical treatment times.

[0023] Figure 7 This is a distribution diagram of the products of calcium carbonate that was not treated by mechanochemical method in Example 1 and was switched to a hydrogen atmosphere at 450°C without decomposition.

[0024] Figure 8 This is a product distribution diagram of the decomposition of calcium carbonate treated by mechanochemical method in Example 1 at a low temperature of 450°C in a hydrogen atmosphere.

[0025] Figure 9 This is a statistical chart showing the selectivity of the products from the decomposition of calcium carbonate treated by the mechanochemical method in Example 1 at 550°C.

[0026] Figure 10 This is a statistical chart showing the selectivity of the decomposition products of calcium carbonate treated for different times by the mechanochemical method in Example 1 at a low temperature of 500°C. Calcium carbonate that was not treated by mechanochemical method and calcium carbonate treated for two hours did not decompose. The gaseous product CO of calcium carbonate treated for more than four hours has a selectivity of more than 99%.

[0027] Figure 11 This is the XRD pattern of calcite before complete mechanochemical treatment in Example 2.

[0028] Figure 12 This is the XRD pattern of amorphous calcite after complete mechanochemical treatment in Example 2.

[0029] Figure 13 This is a TEM image of calcite with intact crystal structure before the mechanochemical treatment in Example 2.

[0030] Figure 14 This is a TEM image of amorphous calcite with disrupted crystal structure after mechanochemical treatment in Example 2.

[0031] Figure 15 This is a temperature-progression decomposition diagram of amorphous calcite under different mechanical and chemical treatment times in Example 2.

[0032] Figure 16 yes Figure 15 A graph showing the temperature variation at the highest point during the decomposition of calcite under different mechanical and chemical treatment times.

[0033] Figure 17This is a distribution diagram of the products of calcite that was not treated by mechanochemical method in Example 2, which was switched to a hydrogen atmosphere at 450°C and did not decompose.

[0034] Figure 18 This is a product distribution diagram of the decomposition of amorphous calcite treated by mechanochemical method in Example 2 at a low temperature of 450°C in a hydrogen atmosphere.

[0035] Figure 19 This is a statistical chart showing the selectivity of the decomposition products of calcite treated for different times by the mechanochemical method in Example 2 at a low temperature of 500°C. Calcite that was not treated by mechanochemical method and calcite treated for two hours did not decompose. The gaseous product CO of calcite treated for more than four hours has a selectivity of more than 99%. Detailed Implementation

[0036] Example 1

[0037] (1) Weigh 10g of calcium carbonate raw material at room temperature and transfer it into a ball mill jar.

[0038] (2) Weigh 50g of a large zirconium ball with a diameter of 20mm, 30g of a medium zirconium ball with a diameter of 6mm, and 20g of a small zirconium ball with a diameter of 2mm. The total mass of the grinding balls is 100g. The mass ratio of zirconium balls to calcium carbonate is 10:1.

[0039] (3) Set the ball mill speed to 400 rpm and the time to 12 h. Open the ball mill jar every 2 h to break up the samples that stick to the wall.

[0040] (4) 0.1 g of the mechanochemically treated carbonate sample was placed in a fixed-bed reactor for in-situ hydrogenation. The reaction temperature was 450 °C, the heating rate was 10 °C / min, the hydrogen flow rate was 100 mL / min, and the reaction time was 8 h.

[0041] Tests showed that the decomposition conversion rate of calcium carbonate after mechanochemical pretreatment in situ hydrogenation was 100%, and the CO selectivity in the gas phase was greater than 99%.

[0042] Example 2

[0043] (1) Weigh 10g of calcite raw material at room temperature and transfer it into a ball mill jar.

[0044] (2) Weigh 50g of a large sphere made of zirconium dioxide with a diameter of 20mm, 30g of a medium sphere made of zirconium dioxide with a diameter of 6mm, and 20g of a small sphere made of zirconium dioxide with a diameter of 2mm. The total mass of the grinding balls is 100g. The mass ratio of the zirconium dioxide balls to calcite is 10:1.

[0045] (3) Set the ball mill speed to 300 rpm and the time to 16 h. Open the ball mill jar every 2 h to break up the samples that stick to the wall.

[0046] (4) 0.1 g of calcite sample after mechanical chemical treatment was placed in a fixed-bed reactor for in-situ hydrogenation refining. The reaction temperature was 450℃, the heating rate was 10℃ / min, the hydrogen flow rate was 50 mL / min, and the reaction time was 8 h.

[0047] Tests showed that the decomposition conversion rate of calcite pretreated by mechanochemical in situ hydrogenation was 100%, and the CO selectivity in the gas phase was greater than 99%.

Claims

1. A method for low-temperature hydrogenation refining of carbonates induced by mechanochemical pretreatment, characterized in that, The specific operation of the method is as follows: under normal temperature and pressure air conditions, carbonate powder and grinding balls are loaded into a ball milling jar and ball milled. After mechanical and chemical treatment for 2-16 hours, completely amorphous carbonate is obtained. Then, the treated carbonate is thermally decomposed at 450-550℃ in a pure hydrogen atmosphere, and metal oxides and synthesis gas without CO2 are prepared at the same time. The carbonate is one or more of calcium carbonate, magnesium carbonate, iron carbonate, and copper carbonate; The mass ratio of the grinding ball to the carbonate is 20-10:

1.

2. The method according to claim 1, characterized in that, The grinding balls are made of zirconium dioxide.

3. The method according to claim 1, characterized in that, The ball mill rotates at a speed of 300-500 rpm.

4. The method according to claim 1, characterized in that, The grinding balls are divided into three types: large balls, medium balls, and small balls. The mass ratio of the large balls, medium balls, and small balls is 4-6:2-4:1-3. The diameter of the large balls is 15-25 mm, the diameter of the medium balls is 5-8 mm, and the diameter of the small balls is 1-3 mm.

5. The method according to claim 1, characterized in that, During ball milling, carbonates clump together and need to be crushed before continuing ball milling.

6. The method according to claim 1, characterized in that, The mechanochemical pretreatment time is 10 h.

7. The method according to claim 1, characterized in that, The flow rate of the pure hydrogen is 50-150 mL / min.

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