Oil-soluble molybdenum disulfide hydrogenation catalyst and preparation method thereof

Abstract

The invention discloses an oil-soluble molybdenum disulfide hydrogenation catalyst and a preparation method thereof. The oil-soluble molybdenum-based catalyst is prepared by mixing and reacting distillate oil in coal tar with sodium hydroxide and an inorganic molybdenum source. The preparation method comprises the following steps: (1) mixing distillate oil of coal tar with deionized water, then adding sodium hydroxide and an inorganic molybdenum source, and stirring to react for 12-36 hours in a nitrogen environment; and (2) adding deionized water into the reaction solution in the step (1), washing for three times, and separating. And (3) dissolving the upper-layer organic phase obtained in the step (2) in an organic solvent, filtering to remove solid particles, then removing the organic solvent through a rotary evaporator, and carrying out vacuum drying to obtain the oil-soluble molybdenum-based catalyst.

Description

Technical Field

[0001] The invention relates to an oil-soluble hydrogenation catalyst, in particular to an oil-soluble molybdenum disulfide hydrogenation catalyst and a preparation method thereof. Background Art

[0002] In recent years, due to the growing demand for more environmentally friendly and lightweight fuels, the shortage of crude oil reserves and the shrinking of conventional oil, there is an urgent need to develop heavy oil upgrading technology. In the field of oil processing, research focuses on the advancement of refining technology for low-value industrial by-products (such as vacuum residue oil, coal tar, etc.) and unconventional oils (such as extra heavy oil, oil sands, etc.) that are regarded as alternative energy sources. According to 2020 data, recoverable reserves of heavy oil account for 40% of total oil reserves, while conventional oil accounts for only 30%. In addition, a large amount of difficult-to-process residues will remain in the processing of conventional oil. Most of my country's crude oil is heavy, and the vacuum residue content is generally as high as 40-50%. The composition of heavy oil is also complex, containing high amounts of sulfur, nitrogen, metals and macromolecular asphaltene, which makes it difficult to lighten heavy oil.

[0003] The slurry bed low-quality oil hydrogenation process has received increasing attention due to its high tolerance to raw materials and superior hydrogenation catalytic effect. The unsupported Mo-based catalysts used in the slurry bed are divided into solid, water-soluble and oil-soluble. Water-soluble precursors, including ammonium heptamolybdate and phosphomolybdic acid, are relatively cheap, but require additional surfactants to improve the dispersion of water droplets containing the precursor in the oil supply. In addition, since the mixing of the precursor with the feed requires a multi-stage preparation process, the complexity and cost of the process will be greatly increased. The oil-soluble precursor is easy to mix with the feed, does not require pretreatment, and can produce the smallest particle size of MoS2. The performance of low-quality oil hydrogenation is currently better than the other two types of Mo-based catalysts. The oil-soluble precursor is often obtained by hydrothermal synthesis of molybdenum oxide and surfactants such as hexadecylamine and sodium oleate, or directly using organic molybdenum such as dialkyl (aryl) dithiocarbamate molybdenum, dialkyl dithiophosphate molybdenum, cyclopentane acid molybdenum, isooctanoic acid molybdenum, hexacarbonyl molybdenum, etc. The former requires a large amount of chemically pure organic reagents, while the latter organic molybdenum is expensive. At the same time, the organic components in the Mo oil-soluble precursor are converted into small molecular organic matter during the heavy oil hydrogenation process, so that the chemically pure substance is converted into low-value industrial light fuel oil. Therefore, the preparation cost of ordinary oil-soluble Mo-based catalysts is high, the regeneration cost is high, and the industrial application is difficult.

[0004] Therefore, finding a low-cost oil-soluble molybdenum disulfide hydrogenation catalyst is crucial to the development of the slurry bed low-quality oil hydrogenation field. Summary of the invention

[0005] The purpose of the present invention is to prepare an oil-soluble molybdenum-based catalyst by mixing a fraction of coal tar with sodium hydroxide and an inorganic molybdenum source.

[0006] The technical solution adopted by the present invention to solve the above technical problems is as follows: (1) Mix the coal tar fraction with deionized water, then add sodium hydroxide and an inorganic molybdenum source, and stir the mixture under nitrogen for 12-36 hours. (2) Add deionized water to the reaction solution in (1) and wash it three times, and then separate it. (3) Dissolve the upper organic phase obtained in (2) in an organic solvent, filter out the solid particles, then remove the organic solvent by rotary evaporator, and vacuum dry to obtain an oil-soluble molybdenum-based catalyst.

[0007] The coal tar distillate oil in step (1) is one of the coal tar fractions cut according to the temperature interval of 5-180°C, such as the gasoline fraction (IBP-180°C) or the diesel fraction (180-360°C) of coal tar.

[0008] The inorganic molybdenum source in step (1) is ammonium heptamolybdate or ammonium tetrathiomolybdate.

[0009] The organic solvent in step (2) is one of toluene, dichloromethane or carbon disulfide.

[0010] Compared with the prior art, the technical solution provided by the present invention has the following technical advantages: the original oil-soluble molybdenum-based catalyst has high production cost and the organic components in the Mo oil-soluble precursor are converted into small molecular organic matter during the heavy oil hydrogenation process, so that a large amount of chemically pure substances are converted into low-value industrial light fuel oil. The preparation cost of ordinary oil-soluble Mo-based catalysts is high, the regeneration cost is high, and the industrial application is difficult. The phenol content in coal tar is usually as high as 20-30%, distributed among different fractions of coal tar. The technical solution provided by the present invention uses coal tar fraction oil to participate in the synthesis of oil-soluble molybdenum-based catalysts, which will not cause a large amount of waste of chemically pure reagents and reduce the preparation cost. The prepared oil-soluble molybdenum-based catalyst has excellent dispersion and hydrogenation performance in inferior oil. Specific implementation methods

[0011] The present invention is further illustrated by way of examples below, but they do not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0012] Implementation Case 1 97 g of gasoline fraction (IBP-180℃) of coal tar was mixed with 100 ml of deionized water, and then 1 g of sodium hydroxide and 0.5 g of ammonium heptamolybdate were added, and the mixture was stirred and reacted for 12 h under nitrogen. Deionized water was added to the reaction solution for washing three times and then separated. The obtained upper organic phase was dissolved in toluene, solid particles were removed by filtration, and then toluene was removed by rotary evaporator and vacuum dried to obtain an oil-soluble molybdenum-based catalyst. It was applied to coal tar hydrogenation to increase the yield of light fuel oil by 50-55%.

[0013] Implementation Case 2 97 g diesel fraction (180-360℃) of coal tar was mixed with 100 ml deionized water, and then 1 g sodium hydroxide and 0.5 g ammonium heptamolybdate were added, and the mixture was stirred and reacted for 24 h under nitrogen atmosphere. Deionized water was added to the reaction solution for washing 3 times, and then separated. The obtained upper organic phase was dissolved in dichloromethane, solid particles were removed by filtration, and then dichloromethane was removed by rotary evaporator, and vacuum dried to obtain an oil-soluble molybdenum-based catalyst. It was applied to the hydrogenation of vacuum residue oil to increase the yield of light fuel oil by 50-60%.

[0014] Implementation Case 3 97 g diesel fraction (180-360 ° C) of coal tar was mixed with 100 ml deionized water, and then 1 g sodium hydroxide and 0.5 g ammonium tetrathiomolybdate were added, and the mixture was stirred for 36 h under nitrogen. Deionized water was added to the reaction solution for washing three times and then separated. The obtained upper organic phase was dissolved in carbon disulfide, the solid particles were removed by filtration, and then the carbon disulfide was removed by a rotary evaporator and vacuum dried to obtain an oil-soluble molybdenum-based catalyst. It was applied to the hydrogenation of coking residue oil to increase the yield of light fuel oil by 50-60%.

Claims

1. An oil-soluble molybdenum disulfide hydrogenation catalyst and a preparation method thereof, the specific steps of which are: (1) Mix the coal tar fraction with deionized water, then add sodium hydroxide and an inorganic molybdenum source, and stir the mixture under nitrogen for 12-36 hours. (2) Add deionized water to the reaction solution in (1) and wash it three times, and then separate it. (3) Dissolve the upper organic phase obtained in (2) in an organic solvent, filter out the solid particles, then remove the organic solvent by rotary evaporator, and vacuum dry to obtain an oil-soluble molybdenum-based catalyst.

2. The method according to claim 1, characterized in that The coal tar distillate oil described in step (1) is one of the coal tar fractions cut according to the temperature interval of 5-180°C, such as the gasoline fraction (IBP-180°C) or the diesel fraction (180-360°C) of coal tar.

3. The method according to claim 1, characterized in that The inorganic molybdenum source in step (1) is ammonium heptamolybdate or ammonium tetrathiomolybdate.

4. The method according to claim 1, characterized in that The organic solvent in step (2) is one of toluene, dichloromethane or carbon disulfide.