A hydrothermal decomposition catalyst and a preparation method thereof

Abstract

The present invention discloses a hydrothermal decomposition catalyst and a preparation method thereof, which relates to the technical field of catalyst preparation and includes the following steps: Step S1, preparation of active components; Step S2, compounding of active components and rare earth oxides; Step S3, surface modification. This hydrothermal decomposition catalyst has remarkable catalytic effect, high catalytic efficiency, good catalytic activity, less reaction coking, high yield of cracked light oil, and low requirements for condition control.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst preparation, and particularly relates to a hydrothermal decomposition catalyst and a preparation method thereof. Background Art

[0002] In recent years, with the continuous advancement of the global industrialization process and the deepening of people's understanding of environmental issues, using coal tar as a raw material and adopting hydrothermal decomposition means to produce clean raw oil has become an effective way to solve the major gap in the domestic vehicle fuel market and alleviate the shortage of petroleum resources in China, and thus has received increasing attention.

[0003] Hydrothermal decomposition refers to a processing process in which, under the conditions of relatively high pressure and temperature, hydrogen reacts with coal tar under the action of a hydrothermal decomposition catalyst to undergo hydrogenation, cracking, and isomerization reactions, and is converted into light oils (such as gasoline, kerosene, diesel, etc.). From the perspective of the reaction process, hydrothermal decomposition is essentially an organic combination of hydrogenation and catalytic cracking processes. The core of coal tar hydrothermal decomposition lies in the hydrothermal decomposition catalyst, and the hydrothermal decomposition catalyst plays a key role in improving the quality of light oil products. It can be seen that it is imperative to develop a hydrothermal decomposition catalyst with high catalytic efficiency, good catalytic activity, excellent performance stability, and low requirements for reaction condition control.

[0004] In the prior art, the catalysts commonly used in coal tar hydrothermal decomposition reactions usually use molybdenum, nickel, cobalt, iron, etc. as active substances and silica-alumina as carriers. Such catalysts are suitable for processing medium and low temperature coal tar, but molybdenum, nickel, etc. are expensive, and the hydrogenation activity of cobalt and iron-based catalysts is relatively poor. Connecting the above active substances in a certain way reduces the cost of the catalyst and improves the hydrogenation activity to a certain extent. However, the desulfurization efficiency of its hydrocracking treatment process is still relatively low, and the obtained light oil product contains more sulfur. When using the light oil product as a base oil to manufacture liquid fuel, further refining is still required.

[0005] To solve the above problems, Chinese patent document CN102784653A discloses a catalyst for producing clean fuel oil from coal tar and a preparation method thereof. The catalyst is composed of a carrier and an active component. Among them, the carrier is composed of alumina, silica, and magnesia, and the active component is composed of WO 3 and NiO or MoO 3 and NiO. The catalyst can be prepared through three steps: carrier preparation, impregnation of the active component, and impregnation of the auxiliary agent. The catalyst is relatively stable and can produce low-sulfur and low-nitrogen naphtha and diesel fractions by hydrotreating coal tar. However, since it needs to be realized through three steps: carrier preparation, impregnation of the active component, and impregnation of the auxiliary agent, the preparation process is relatively complex, the process is relatively long, and the condition control requirements are high.

[0006] Therefore, the development of a hydrothermal decomposition catalyst with remarkable catalytic effect, high catalytic efficiency, good catalytic activity, less reaction coking, high yield of cracked light oil and low requirements for condition control, as well as its preparation method, meets the market demand, has broad market value and application prospects, and is of great significance for promoting the development of hydrothermal decomposition technology. Summary of the Invention

[0007] The main object of the present invention is to provide a hydrothermal decomposition catalyst with remarkable catalytic effect, high catalytic efficiency, good catalytic activity, less reaction coking, high yield of cracked light oil and low requirements for condition control, as well as its preparation method.

[0008] To achieve the above object, the present invention provides a preparation method of a hydrothermal decomposition catalyst, which includes the following steps:

[0009] Step S1, preparation of active components: Ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source and citric acid are dispersed in deionized water. After stirring evenly, spray drying is carried out to obtain precursor particles; the precursor particles are heated from room temperature to 700 - 800 °C at a rate of 5 - 8 °C / min, then kept at this temperature for 8 - 12 h and naturally cooled to obtain active components;

[0010] Step S2, compounding of active components and rare earth oxides: The active components and rare earth oxides prepared in step S1 are mixed evenly to obtain a composite of active components and rare earth oxides;

[0011] Step S3, surface modification: The composite, triethoxysilyl acetic acid and quaternary ammonium salt calix[3]carbazole are added to water, stirred at 60 - 80 °C for 4 - 6 hours, the solvent is removed by rotary evaporation, then washed with acetone 3 - 6 times, and finally dried in a vacuum drying oven at 80 - 90 °C to constant weight to obtain the hydrothermal decomposition catalyst.

[0012] Preferably, in step S1, the mass ratio of ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source, citric acid and deionized water is 0.4:0.1:(3 - 5):(0.01 - 0.03):0.3:(0.03 - 0.05):(1 - 2):(30 - 40).

[0013] Preferably, the hypophosphite is sodium hypophosphite.

[0014] Preferably, the iron source is at least one of iron nitrate and iron chloride; the iridium source is iridium nitrate.

[0015] Preferably, the manganese source is at least one of manganese nitrate and manganese chloride; the niobium source is one or several of niobium nitrate, niobium oxalate and niobium acetate.

[0016] Preferably, the mass ratio of the active ingredient to the rare earth oxide in step S2 is (3 - 5):1.

[0017] Preferably, the rare earth oxide is a mixture formed by mixing lanthanum oxide and cerium oxide in a mass ratio of 1:(1 - 2).

[0018] Preferably, the particle size of the rare earth oxide is 800 - 1200 mesh.

[0019] Preferably, the mass ratio of the complex, triethoxysilyl acetic acid, quaternary ammonium calix[3]carbazole, and water in step S3 is 1:(0.1 - 0.2):0.1:(5 - 8).

[0020] Preferably, there is no special requirement for the source of the quaternary ammonium calix[3]carbazole. In one embodiment of the present invention, the quaternary ammonium calix[3]carbazole is prepared by the method in Example 2 of Chinese Patent Document CN109836429B.

[0021] Another object of the present invention is to provide a hydrothermal decomposition catalyst prepared by the preparation method of the hydrothermal decomposition catalyst described above.

[0022] Due to the application of the above technical solutions, the present invention has the following beneficial effects:

[0023] (1) The hydrothermal decomposition catalyst disclosed in the present invention has a simple preparation process, convenient operation control, high preparation efficiency and finished product qualification rate, a short process, and low condition control requirements, and is suitable for continuous large-scale production.

[0024] (2) The hydrothermal decomposition catalyst disclosed in the present invention first prepares an active ingredient precursor by spray drying and then sinters to form an active ingredient. The active ingredient contains molybdenum, iron, iridium, manganese, niobium, phosphorus, sulfur, and nitrogen, etc. They cooperate with each other and act together, which can effectively improve the catalyst activity, reduce the preparation cost, make the prepared hydrothermal decomposition catalyst have a significant catalytic effect, high catalytic efficiency, good catalytic activity, less reaction coking, high light oil yield of cracking, and low condition control requirements.

[0025] (3) The hydrothermal decomposition catalyst disclosed in the present invention further improves the catalytic effect, catalytic activity and catalytic efficiency by compounding the active ingredient with the rare earth oxide, and they cooperate with each other and act together; through surface modification, a calixcarbazole structure is introduced on the catalyst surface, which improves the solubility of the catalyst in coal tar and can be evenly dispersed in the reaction system, thereby improving the reaction efficiency of the hydrothermal decomposition reaction and improving the catalytic effect. Detailed implementation mode

[0026] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and other obvious variations can be conceived by those skilled in the art. Example 1

[0027] A preparation method of a hydrothermal decomposition catalyst includes the following steps:

[0028] Step S1, preparation of the active component: Disperse ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source and citric acid in deionized water, stir evenly, and then perform spray drying to obtain precursor particles; heat the precursor particles from room temperature to 700 °C at a rate of 5 °C / min, then keep them at this temperature for 8 h and then cool naturally to obtain the active component;

[0029] Step S2, compounding of the active component and rare earth oxide: Mix the active component and rare earth oxide prepared in step S1 evenly to obtain a composite of the active component and rare earth oxide;

[0030] Step S3, surface modification: Add the composite, triethoxysilyl acetic acid, quaternary ammonium salt-based calix[3]carbazole to water, stir at 60 °C for 4 hours, rotary evaporate to remove the solvent, then wash with acetone 3 times, and finally place it in a vacuum drying oven and dry at 80 °C to constant weight to obtain the hydrothermal decomposition catalyst.

[0031] In step S1, the mass ratio of ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source, citric acid, and deionized water is 0.4:0.1:5:0.01:0.3:0.03:1:30; the hypophosphite is sodium hypophosphite; the iron source is iron nitrate; the iridium source is iridium nitrate; the manganese source is manganese nitrate; the niobium source is niobium nitrate.

[0032] In step S2, the mass ratio of the active component to the rare earth oxide is 3:1; the rare earth oxide is a mixture formed by mixing lanthanum oxide and cerium oxide in a mass ratio of 1:1; the particle size of the rare earth oxide is 800 mesh.

[0033] In step S3, the mass ratio of the composite, triethoxysilyl acetic acid, quaternary ammonium salt-based calix[3]carbazole, and water is 1:0.1:0.1:5; the quaternary ammonium salt-based calix[3]carbazole is prepared by the method of Example 2 in Chinese Patent Document CN109836429B.

[0034] A hydrothermal decomposition catalyst prepared by using the preparation method of the hydrothermal decomposition catalyst. Example 2

[0035] A preparation method of a hydrothermal decomposition catalyst includes the following steps:

[0036] Step S1, preparation of the active ingredient: Ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source and citric acid are dispersed in deionized water. After stirring evenly, spray drying is carried out to obtain precursor particles; The precursor particles are heated from room temperature to 730 °C at a rate of 6 °C / min, then kept at this temperature for 9 h and then naturally cooled to obtain the active ingredient;

[0037] Step S2, compounding of the active ingredient and rare earth oxide: The active ingredient and rare earth oxide prepared in Step S1 are mixed evenly to obtain a composite of the active ingredient and rare earth oxide;

[0038] Step S3, surface modification: The composite, triethoxysilylacetic acid, and quaternary ammonium calix[3]carbazole are added to water, stirred at 65 °C for 4.5 h, the solvent is removed by rotary evaporation, then washed 4 times with acetone, and finally dried to constant weight at 83 °C in a vacuum drying oven to obtain a hydrothermal decomposition catalyst.

[0039] In Step S1, the mass ratio of ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source, citric acid, and deionized water is 0.4:0.1:4.5:0.015:0.3:0.035:1.2:33; The hypophosphite is sodium hypophosphite; The iron source is ferric chloride; The iridium source is iridium nitrate; The manganese source is manganese chloride; The niobium source is niobium oxalate.

[0040] In Step S2, the mass ratio of the active ingredient to the rare earth oxide is 3.5:1; The rare earth oxide is a mixture formed by mixing lanthanum oxide and cerium oxide in a mass ratio of 1:1.2; The particle size of the rare earth oxide is 900 mesh.

[0041] In Step S3, the mass ratio of the composite, triethoxysilylacetic acid, quaternary ammonium calix[3]carbazole, and water is 1:0.13:0.1:6; The quaternary ammonium calix[3]carbazole is prepared according to the method in Example 2 of Chinese invention patent document CN109836429B.

[0042] A hydrothermal decomposition catalyst prepared by the preparation method of the above-mentioned hydrothermal decomposition catalyst. Example 3

[0043] A preparation method of a hydrothermal decomposition catalyst, comprising the following steps:

[0044] Step S1, preparation of the active ingredient: Ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source and citric acid are dispersed in deionized water. After stirring evenly, spray drying is carried out to obtain precursor particles; The precursor particles are heated from room temperature to 750 °C at a rate of 6.5 °C / min, then kept at this temperature for 10 h and then naturally cooled to obtain the active ingredient;

[0045] Step S2. Composite of active ingredient and rare earth oxide: Mix the active ingredient and rare earth oxide prepared in Step S1 evenly to obtain a composite of the active ingredient and rare earth oxide;

[0046] Step S3. Surface modification: Add the composite, triethoxysilyl acetic acid, and quaternary ammonium calix[3]carbazole into water, stir at 70 °C for 5 hours, remove the solvent by rotary evaporation, then wash with acetone 5 times, and finally dry to constant weight at 85 °C in a vacuum drying oven to obtain a hydrothermal decomposition catalyst.

[0047] In Step S1, the mass ratio of ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source, citric acid, and deionized water is 0.4:0.1:4:0.02:0.3:0.04:1.5:35; the hypophosphite is sodium hypophosphite; the iron source is iron nitrate; the iridium source is iridium nitrate; the manganese source is manganese nitrate; the niobium source is niobium oxalate.

[0048] In Step S2, the mass ratio of the active ingredient and rare earth oxide is 4:1; the rare earth oxide is a mixture formed by mixing lanthanum oxide and cerium oxide in a mass ratio of 1:1.5; the particle size of the rare earth oxide is 1000 mesh.

[0049] In Step S3, the mass ratio of the composite, triethoxysilyl acetic acid, quaternary ammonium calix[3]carbazole, and water is 1:0.15:0.1:6.5; the quaternary ammonium calix[3]carbazole is prepared by the method in Example 2 of Chinese Patent Document CN109836429B.

[0050] A hydrothermal decomposition catalyst prepared by the preparation method of the above-mentioned hydrothermal decomposition catalyst. Example 4

[0051] A preparation method of a hydrothermal decomposition catalyst, comprising the following steps:

[0052] Step S1. Preparation of active ingredient: Disperse ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source, and citric acid in deionized water, stir evenly, and then perform spray drying to obtain precursor particles; heat the precursor particles from room temperature to 780 °C at a rate of 7.5 °C / min, then keep them at this temperature for 11 h and cool naturally to obtain the active ingredient;

[0053] Step S2. Composite of active ingredient and rare earth oxide: Mix the active ingredient and rare earth oxide prepared in Step S1 evenly to obtain a composite of the active ingredient and rare earth oxide;

[0054] Step S3, surface modification: Add the composite, triethoxysilylacetic acid, and quaternary ammonium calix[3]carbazole to water, stir at 75 °C for 5.5 hours, remove the solvent by rotary evaporation, then wash with acetone 6 times, and finally dry in a vacuum drying oven at 88 °C to constant weight to obtain the hydrothermal decomposition catalyst.

[0055] In step S1, the mass ratio of ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source, citric acid, and deionized water is 0.4:0.1:3.5:0.025:0.3:0.045:1.8:38; the hypophosphite is sodium hypophosphite; the iron source is a mixture formed by mixing iron nitrate and iron chloride in a mass ratio of 3:5; the iridium source is iridium nitrate; the manganese source is a mixture formed by mixing manganese nitrate and manganese chloride in a mass ratio of 1:2; the niobium source is a mixture formed by mixing niobium nitrate, niobium oxalate, and niobium acetate in a mass ratio of 1:3:1.

[0056] In step S2, the mass ratio of the active ingredient to the rare earth oxide is 4.5:1; the rare earth oxide is a mixture formed by mixing lanthanum oxide and cerium oxide in a mass ratio of 1:1.8; the particle size of the rare earth oxide is 1100 mesh.

[0057] In step S3, the mass ratio of the composite, triethoxysilylacetic acid, quaternary ammonium calix[3]carbazole, and water is 1:0.18:0.1:7.5; the quaternary ammonium calix[3]carbazole is prepared by the method of Example 2 in Chinese invention patent document CN109836429B.

[0058] A hydrothermal decomposition catalyst prepared by the preparation method of the above-mentioned hydrothermal decomposition catalyst. Example 5

[0059] A preparation method of a hydrothermal decomposition catalyst, comprising the following steps:

[0060] Step S1, preparation of the active ingredient: Disperse ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source, and citric acid in deionized water, stir evenly, and then perform spray drying to obtain precursor particles; heat the precursor particles from room temperature to 800 °C at a rate of 8 °C / min, and then keep them at this temperature for 12 h and then cool naturally to obtain the active ingredient;

[0061] Step S2, compounding of the active ingredient and the rare earth oxide: Mix the active ingredient and the rare earth oxide prepared in step S1 evenly to obtain a composite of the active ingredient and the rare earth oxide;

[0062] Step S3, Surface Modification: Add the composite, triethoxysilyl acetic acid, and quaternary ammonium calix[3]carbazole into water, stir at 80 °C for 6 hours, remove the solvent by rotary evaporation, then wash with acetone 6 times, and finally dry in a vacuum drying oven at 90 °C to constant weight to obtain the hydrothermal decomposition catalyst.

[0063] In step S1, the mass ratio of ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source, citric acid, and deionized water is 0.4:0.1:3:0.03:0.3:0.05:2:40; the hypophosphite is sodium hypophosphite; the iron source is iron nitrate; the iridium source is iridium nitrate; the manganese source is manganese nitrate; the niobium source is niobium acetate.

[0064] In step S2, the mass ratio of the active ingredient to the rare earth oxide is 5:1; the rare earth oxide is a mixture formed by mixing lanthanum oxide and cerium oxide in a mass ratio of 1:2; the particle size of the rare earth oxide is 1200 mesh.

[0065] In step S3, the mass ratio of the composite, triethoxysilyl acetic acid, quaternary ammonium calix[3]carbazole, and water is 1:0.2:0.1:8; the quaternary ammonium calix[3]carbazole is prepared according to the method in Example 2 of Chinese Invention Patent Document CN109836429B.

[0066] A hydrothermal decomposition catalyst prepared by the preparation method using the above-mentioned hydrothermal decomposition catalyst.

[0067] Comparative Example 1

[0068] A hydrothermal decomposition catalyst, which is basically the same as Example 1, except that ammonium tetrathiomolybdate and iridium source are not added.

[0069] Comparative Example 2

[0070] A hydrothermal decomposition catalyst, which is basically the same as Example 1, except that niobium source and rare earth oxide are not added.

[0071] Comparative Example 3

[0072] A hydrothermal decomposition catalyst, which is basically the same as Example 1, except that step S3, surface modification, is not performed.

[0073] To further illustrate the beneficial technical effects of the hydrocracking catalysts prepared in the embodiments of the present invention, the hydrocracking catalysts prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to relevant performance tests. The test results are shown in Table 1, and the test methods are as follows: Send coal tar into the hydrocracking reactor, and carry out hydrocracking of the coal tar in the presence of the hydrocracking catalysts of each example; the pressure during the hydrocracking is 7 MPa, and the temperature is 350 °C; the mass of the hydrocracking catalyst accounts for 0.01% of the mass of the coal tar; Use a separator to separate the light fractions below 350 °C in the hydrocracking products, and count and calculate the yield of the fractions below 350 °C and the mass percentage concentration of sulfur therein.

[0074] Table 1

[0075] Project Yield of fractions below 350 °C Mass percentage concentration of sulfur in fractions below 350 °C Unit % % Example 1 89.7 0.05 Example 2 90.5 0.03 Example 3 91.0 0.03 Example 4 92.2 0.02 Example 5 92.8 0.01 Comparative Example 1 80.5 0.16 Comparative Example 2 83.6 0.12 Comparative Example 3 88.9 0.08

[0076] As can be seen from Table 1, compared with the products of the comparative examples, the hydrocracking catalysts disclosed in the embodiments of the present invention have better catalytic hydrodesulfurization effects; the addition of ammonium tetrathiomolybdate, iridium source, niobium source, rare earth oxide and the surface modification step are beneficial to improving the above performance.

[0077] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of a hydrothermal decomposition catalyst, characterized in that, it comprises the following steps: Step S1, preparation of the active ingredient: Disperse ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source and citric acid in deionized water, stir evenly, and then carry out spray drying to obtain precursor particles; Heat the precursor particles from room temperature to 700-800 °C at a rate of 5-8 °C / min, then keep them at this temperature for 8-12 h and then cool naturally to obtain the active ingredient; Step S2, compounding of the active ingredient and rare earth oxide: Mix the active ingredient and rare earth oxide prepared in Step S1 evenly to obtain a composite of the active ingredient and rare earth oxide; The rare earth oxide is a mixture formed by mixing lanthanum oxide and cerium oxide in a mass ratio of 1:(1-2); Step S3, surface modification: Add the composite, triethoxysilyl acetic acid, and quaternary ammonium calix[3]carbazole to water, stir at 60-80 °C for 4-6 hours, rotary evaporate to remove the solvent, then wash with acetone 3-6 times, and finally place it in a vacuum drying oven and dry at 80-90 °C to constant weight to obtain the hydrothermal decomposition catalyst.

2. The preparation method of the hydrothermal decomposition catalyst according to claim 1, characterized in that, in Step S1, the mass ratio of ammonium tetrathiomolybdate, hypophosphite, iron source, iridium source, manganese source, niobium source, citric acid, and deionized water is 0.4:0.1:(3-5):(0.01-0.03):0.3:(0.03-0.05):(1-2):(30-40).

3. The preparation method of the hydrothermal decomposition catalyst according to claim 1, characterized in that, the hypophosphite is sodium hypophosphite.

4. The preparation method of the hydrothermal decomposition catalyst according to claim 1, characterized in that, the iron source is at least one of iron nitrate and iron chloride; the iridium source is iridium nitrate.

5. The preparation method of the hydrothermal decomposition catalyst according to claim 1, characterized in that, the manganese source is at least one of manganese nitrate and manganese chloride; the niobium source is one or several of niobium nitrate, niobium oxalate, and niobium acetate.

6. The preparation method of the hydrothermal decomposition catalyst according to claim 1, characterized in that, in Step S2, the mass ratio of the active ingredient and rare earth oxide is (3-5):

1.

7. The preparation method of the hydrothermal decomposition catalyst according to claim 1, characterized in that, the particle size of the rare earth oxide is 800-1200 mesh.

8. The preparation method of the hydrothermal decomposition catalyst according to claim 1, characterized in that, in Step S3, the mass ratio of the composite, triethoxysilyl acetic acid, quaternary ammonium calix[3]carbazole, and water is 1:(0.1-0.2):0.1:(5-8).

9. A hydrothermal decomposition catalyst prepared by the preparation method of the hydrothermal decomposition catalyst according to any one of claims 1-8.