CN110964566B

CN110964566B - Production method of ultra-low sulfur diesel

Info

Publication number: CN110964566B
Application number: CN201811145225.0A
Authority: CN
Inventors: 丁石; 习远兵; 张锐; 葛泮珠; 陈文斌
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2018-09-29
Filing date: 2018-09-29
Publication date: 2022-01-04
Anticipated expiration: 2038-09-29
Also published as: CN110964566A

Abstract

The invention relates to a method for producing ultra-low sulfur diesel, which comprises the steps of mixing diesel raw oil and hydrogen-containing material flow, reacting in a first hydrogenation reaction zone and a second hydrogenation reaction zone in sequence, and carrying out gas-liquid separation and liquid phase material fractionation on the hydrogenated materials to obtain an ultra-low sulfur diesel product. The method provided by the invention can be used for treating high-sulfur straight-run diesel oil or inferior secondary processing diesel oil, and producing an ultra-low-sulfur diesel oil product with the sulfur content of less than 10 mu g/g under relatively mild conditions, and the whole catalyst system has better stability and obviously improves the running period of the device.

Description

Production method of ultra-low sulfur diesel

Technical Field

The invention relates to the field of oil refining chemical industry, in particular to a method for producing ultra-low sulfur diesel oil by using inferior raw oil.

Background

The problem of environmental pollution caused by automobile exhaust has attracted much attention on a global scale. Diesel fuel is an important vehicle fuel, and Sulfur Oxides (SOX), Nitrogen Oxides (NOX), Particulate Matter (PM), and the like contained in exhaust gas discharged after combustion are important causes of air pollution. The worldwide diesel oil standard is becoming more and more strict, and the production of environment-friendly low-sulfur or ultra-low-sulfur diesel oil becomes a problem which is generally regarded by governments and oil refining enterprises in various countries around the world. European Union countries have begun to implement the European four emission standard for light diesel fuel for vehicles with sulfur content less than 50 μ g/g in 2005 and the European five emission standard for vehicle with sulfur content less than 10 μ g/g in 2009. China already executes the national five-diesel standard with the sulfur content less than 10 mug/g in 2017, plans to execute the national six-diesel standard in 2019, and further requires that the polycyclic aromatic hydrocarbon content of a diesel product is reduced from 11% to 7%. Although the specifications of diesel oil products are different from country to country, ultralow-sulfur diesel oil with lower sulfur content is a main target pursued by oil refining enterprises all over the world.

The hydrogenation technology is used as an effective desulfurization and denitrification means, and plays an increasingly important role in the production of clean fuels. However, in the prior art, the process of producing ultra-low sulfur diesel oil from poor-quality diesel oil raw material has the problems of high reaction severity, poor catalyst stability, quick inactivation and short overall operation period of the device.

Therefore, the production method of how to stably produce ultra-low sulfur diesel oil for a long period under milder conditions is one of the most urgent needs of the oil refining industry.

Disclosure of Invention

The invention aims to provide a production method of ultra-low sulfur diesel oil, which aims to solve the problems of harsh reaction conditions and poor catalyst stability in the prior art.

The method provided by the invention comprises the steps that after raw diesel oil and hydrogen-containing material flow are mixed, the mixture sequentially passes through a first hydrogenation reaction zone and a second hydrogenation reaction zone, a hydrogenation catalyst I is filled in the first hydrogenation reaction zone, a hydrogenation catalyst II is filled in the second hydrogenation reaction zone, and the material after hydrogenation reaction is subjected to gas-liquid separation and liquid-phase material fractionation to obtain the ultra-low sulfur diesel oil with the sulfur content of less than 10 mu g/g;

the reaction temperature of the first hydrogenation reaction zone is lower than that of the second hydrogenation reaction zone;

the hydrogenation catalyst II contains an inorganic refractory component, a hydrodesulfurization catalytic active component, and an alcohol and a carboxylic acid; wherein the inorganic refractory component contains at least one of silica, magnesia, calcia, zirconia and titania, and at least one hydrodesulfurization catalytic active component;

the hydrogenation catalyst II has a pore diameter of 2-40nm and a pore diameter of 100-300nm, wherein the pore volume of the pore diameter of 2-40nm accounts for 60-95% of the total pore volume, and the pore volume of 100-300nm accounts for 0.5-30% of the total pore volume.

The diesel raw oil is diesel fraction produced by an atmospheric and vacuum distillation process or other processes, or a mixture of diesel fractions produced by different processes. Preferably, the total sulfur content of the diesel raw oil is not more than 30000 mu g/g, the nitrogen content is not more than 3000 mu g/g, the total aromatic hydrocarbon content is not more than 80 weight percent, and the distillation range is less than 380 ℃.

In the invention, in order to reduce the reaction severity of processing the ultra-low sulfur diesel oil and reduce the influence of reaction interferents on the hydrogenation ultra-deep desulfurization process, two hydrogenation reaction zones connected in series are adopted, and a hydrogenation catalyst I is filled in the first hydrogenation reaction zone, wherein the hydrogenation catalyst can be a conventional hydrogenation protective agent or a conventional hydrofining catalyst. The second hydrogenation reaction zone is filled with the hydrogenation catalyst II, and the hydrogenation catalyst II provided by the invention has higher reaction performance of ultra-deep hydrodesulfurization.

In one preferred embodiment of the present invention, in the first hydrogenation reaction zone: the reaction temperature is 260 ℃ and 320 ℃, and the volume space velocity is 8.0-30.0h^-1The hydrogen partial pressure is 2.0-10.0MPa, and the volume ratio of hydrogen to oil is 100-1000: 1. In the second hydrogenation reaction zone: the reaction temperature is 260 ℃ and 420 ℃, and the volume space velocity is 0.4-4.0h^-1The hydrogen partial pressure is 2.0-10.0MPa, and the hydrogen-oil volume ratio is 100-; further preferably, the reaction temperature is 320-^-1The hydrogen partial pressure is 4.0-8.0MPa, and the volume ratio of hydrogen to oil is 300-600: 1.

In a preferable case, the reaction temperature of the first hydrogenation reaction zone is lower than that of the second hydrogenation reaction zone by 5 to 80 ℃ and 20 to 80 ℃.

Wherein, the second hydrogenation reaction zone is provided with one hydrogenation reactor or a plurality of hydrogenation reactors;

preferably, when the second hydrogenation reaction zone is provided with a plurality of hydrogenation reactors, a heat exchanger is arranged between each reactor to adjust the inlet temperature of each reactor.

In the present invention, the hydrogenation catalyst I may be a commercially available distillate oil hydrorefining catalyst, a commercially available distillate oil hydrogenation protective agent, or a laboratory catalyst having a hydrorefining or hydrogenation protection function.

More preferably, the hydrogenation catalyst I is a supported non-noble metal catalyst, which contains a carrier, and at least one group VIII metal element and at least one group VIB metal element supported on the carrier, and the content of the group VIII metal element is 0.5 to 5 wt%, and the content of the group VIB metal element is 1 to 10 wt%, calculated as oxides, based on the total amount of the hydrogenation catalyst I.

In the invention, the hydrogenation catalyst II has higher reaction performance, wherein the pore channel structures of the hydrogenation catalyst II are respectively concentrated between 2-40nm and 100-300 nm. In the poor diesel distillate oil, the size of reactant molecules is larger, so that a larger reaction space is inevitably needed, and the pore channel with the size of 100-300nm in the hydrogenation catalyst II can provide an enough place for the diffusion of the reactants, so that the accessibility of the reactants and an active center is promoted, and the performance of the hydrogenation catalyst II is obviously improved.

Preferably, the pore volume of pores with a pore diameter of 2-40nm accounts for 75-90% of the total pore volume, and the pore volume of pores with a pore diameter of 100-300nm accounts for 5-15% of the total pore volume. Wherein the pore volume of pores with a diameter of 2-4nm is not more than 10% of the total pore volume.

According to the invention, the specific surface area of the hydrogenation catalyst II and the pore distribution, the pore diameter and the pore volume of 2-40nm are determined by a low-temperature nitrogen adsorption method (meeting the GB/T5816-1995 standard), and the pore distribution, the pore diameter and the pore volume of 100-300nm are determined by a mercury intrusion method. The pore volume of the hydrogenation catalyst II with the pore diameter less than 100nm is measured by a low-temperature nitrogen adsorption method, the pore volume of the hydrogenation catalyst II with the pore diameter more than 100nm is measured by a mercury intrusion method, and the pore volume of the hydrogenation catalyst II is the sum of the pore volume and the pore volume. The average pore diameter was calculated according to the cylindrical pore model (average pore diameter ═ total pore volume × 4000/specific surface area).

Preferably, the specific surface area of the hydrogenation catalyst II is 70-200m²A/g, preferably from 90 to 180m²Pore volume of 0.15 to 0.6mL/g, preferably 0.2 to 0.4mL/g, and average pore diameter of 5 to 25nm, preferably 8 to 15 nm. Wherein, the specific surface area, the pore volume and the average pore diameter are measured after the catalyst is calcined at 400 ℃ for 3 hours.

According to the invention, the pore diameter of 2-40nm means a pore diameter of 2nm or more and less than 40nm, and the pore diameter of 100-300nm means a pore diameter of 100nm or more and less than 300nm, unless otherwise stated. The average pore diameter of 5 to 25nm means that the average of the pore diameters of all pores of the catalyst is not less than 5nm and not more than 25 nm. The pore diameter of 2-4nm is larger than or equal to 2nm and smaller than 4 nm.

In a preferable case, in the hydrogenation catalyst II, the hydrodesulfurization catalytic active components are group VIII metal elements and group VIB metal elements; wherein, in the hydrogenation catalyst II, the content of the VIII group metal element is 15-35 wt%, preferably 20-30 wt% based on the dry weight of the catalyst and calculated by oxide; the content of group VIB metal elements is from 35 to 75% by weight, preferably from 40 to 65% by weight.

Further preferably, the group VIII metal element is selected from at least one of iron, cobalt, nickel, ruthenium, rhodium and palladium, and the group VIB metal element is selected from at least one of chromium, molybdenum and tungsten.

Preferably, the hydrodesulfurization catalytic active component contained in the inorganic refractory component is a group VIII metal element, and the content of the group VIII metal element contained in the inorganic refractory component is 60-90% of the total content of the group VIII metal elements in the catalyst.

The inventors of the present invention found in their studies that, preferably, by including a part of the group VIII metal element in the inorganic refractory component, the content of the active component in the hydrogenation catalyst II can be further increased, thereby further improving the hydrorefining performance of the hydrogenation catalyst II, particularly the performance of ultra-deep hydrodesulfurization.

The silicon oxide, magnesium oxide, calcium oxide, zirconium oxide and titanium oxide contained in the inorganic refractory component are basically inert substances and are difficult to combine with the VIII element to form a compound with a stable structure, so that the utilization rate of the VIII element is improved. In addition, the acting force of the inorganic refractory components and other active components of the hydrogenation catalyst II is weaker, so that the growth of an active phase of the hydrogenation catalyst II can be promoted, and the reaction performance of the hydrogenation catalyst II is further promoted.

According to the present invention, it is preferred that the inorganic refractory component is contained in an amount of 5 to 40% by weight, more preferably 10 to 30% by weight, based on the dry weight of the hydrogenation catalyst II.

Here, the dry weight of the inorganic refractory powder is a weight determined by calcining a sample at 600 ℃ for 4 hours, and the dry weight of the hydrogenation catalyst II is a weight determined by calcining a sample at 400 ℃ for 3 hours. The dry basis weights appearing hereinafter are equally applicable to this definition. It can be known to those skilled in the art that the alcohol and the organic acid contained in the catalyst are decomposed and volatilized at high temperature in the case of calculation on a dry weight basis, and thus, the contents of the alcohol and the organic acid are not calculated on a dry weight basis.

The inventors of the present invention found in their research that the introduction of an alcohol, preferably an organic alcohol compound, into the hydrogenation catalyst II can effectively protect the active components in the hydrogenation catalyst II, and the introduction of a carboxylic acid compound into the hydrogenation catalyst II can improve the activity of the hydrogenation catalyst II, and in the case where both are present, a synergistic effect can be obtained. Therefore, the introduction of the alcohol and the carboxylic acid into the hydrogenation catalyst II can play a role in protecting the catalyst active component and improving the catalyst activity, and the molar number of the alcohol to the dry-basis mass ratio of the inorganic refractory component is 0.005-0.03: 1, preferably 0.01 to 0.02: 1; the dry mass ratio of the carboxylic acid to the inorganic refractory component is 0.002 to 0.1, preferably 0.02 to 0.06.

Preferably, the alcohol is selected from at least one of C1-18 monohydric alcohols, preferably C1-10 monohydric alcohols (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 monohydric alcohols) (such as but not limited to methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, heptanol), ethylene glycol, polyethylene glycol, glycerol, polyglycerol, erythritol, pentaerythritol, xylitol, sorbitol, and trimethylolethane.

Preferably, the carboxylic acid is selected from at least one of C1-18 monobasic saturated carboxylic acids (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18 monobasic saturated carboxylic acids) (e.g., but not limited to, formic acid, acetic acid, propionic acid, octanoic acid, valeric acid, hexanoic acid, decanoic acid, pentanoic acid), C7-10 phenyl acids (e.g., C7, C8, C9, C10 phenyl acids) (e.g., but not limited to, benzoic acid, phenylacetic acid, phthalic acid, terephthalic acid), citric acid, adipic acid, malonic acid, succinic acid, maleic acid, tartaric acid, and the like.

According to a preferred embodiment of the present invention, in order to further improve the performance of the hydrogenation catalyst II, the hydrogenation catalyst II further comprises phosphorus, preferably P₂O₅Exist in the form of (1). Preferably, on a dry basis, with the hydrogenation catalyst IIBased on weight and expressed as P₂O₅The content of the phosphorus element is 0.8 to 10% by weight, more preferably 1 to 8% by weight.

According to the present invention, preferably, the hydrogenation catalyst II is a shaped catalyst, and the shape of the hydrogenation catalyst II is preferably a cylinder, a clover or a honeycomb.

The hydrogenation catalyst II of the present invention is preferably prepared by a method comprising:

(1) mixing a precursor containing at least one of silicon oxide, magnesium oxide, calcium oxide, zirconium oxide and titanium oxide with a precursor of a part of hydrodesulfurization catalytic active component, and roasting to obtain an inorganic refractory component, wherein the roasting temperature is 300-900 ℃, and preferably 400-800 ℃; the roasting time is 1-15h, preferably 3-8 h;

(2) mixing alcohol, carboxylic acid and the precursor of the residual hydrodesulfurization catalytic active component to obtain impregnation liquid;

(3) mixing the inorganic refractory component with the impregnation liquid, molding and drying the obtained mixture, wherein the drying temperature is 50-250 ℃, and preferably 100-200 ℃; the drying time is 2-10h, preferably 3-8h, and the hydrogenation catalyst II is obtained.

According to the invention, the precursors of the hydrodesulfurization catalytic active components are preferably precursors of group VIII metal elements and of group VIB metal elements; wherein, the precursors of the VIII group metal elements and the VIB group metal elements are used in an amount which is calculated by oxides based on the dry weight of the catalyst, specifically, the content of the VIII group metal elements is 15-35 wt%, preferably 20-30 wt%; the content of group VIB metal elements is from 35 to 75% by weight, preferably from 40 to 65% by weight; the group VIII metal element is preferably at least one selected from iron, cobalt, nickel, ruthenium, rhodium and palladium, and the group VIB metal element is preferably at least one selected from chromium, molybdenum and tungsten.

According to the present invention, in the precursor of the hydrodesulfurization catalytic active component, the precursor of the iron element may include, but is not limited to, one or more of iron nitrate, iron oxide, basic iron carbonate and iron acetate, the precursor of the cobalt element may include, but is not limited to, one or more of cobalt nitrate, basic cobalt carbonate, cobalt acetate and cobalt oxide, the precursor of the nickel element may include, but is not limited to, one or more of nickel nitrate, basic nickel carbonate, nickel acetate and nickel oxide, the precursor of the ruthenium element may include, but is not limited to, one or more of ruthenium nitrate, ruthenium acetate, ruthenium oxide and ruthenium hydroxide, the precursor of the rhodium element may include, but is not limited to, one or more of rhodium nitrate, rhodium hydroxide and rhodium oxide, and the precursor of the palladium element may include, but is not limited to, one or more of palladium nitrate, palladium oxide and palladium hydroxide, the precursors of the chromium element can include but are not limited to one or more of chromium nitrate, chromium oxide, chromium hydroxide and chromium acetate, the precursors of the molybdenum element can include but is not limited to one or more of ammonium heptamolybdate, ammonium molybdate, ammonium phosphomolybdate and molybdenum oxide, and the precursors of the tungsten element can include but is not limited to one or more of ammonium metatungstate, ammonium ethylmetatungstate and tungsten oxide.

In the step (1) of the preparation method, the precursor of silica, magnesia, calcia, zirconia, titania may be various substances that can provide silica, magnesia, calcia, zirconia, titania under the roasting condition, for example, the silica precursor may be silica sol, silica white, silica, etc.; the magnesium oxide precursor is magnesium hydroxide, magnesium nitrate, magnesium carbonate, magnesium acetate, magnesium oxide and the like; the precursor of the calcium oxide is calcium hydroxide, calcium carbonate, calcium oxalate, calcium nitrate, calcium acetate, calcium oxide and the like; the zirconia precursor is zirconium hydroxide, zirconium carbonate, zirconium nitrate, zirconium acetate, zirconia and the like; the precursor of the titanium oxide is titanium hydroxide, titanium nitrate, titanium acetate, zirconium oxide and the like.

Preferably, the average pore diameter of the precursors of the silicon oxide, the magnesium oxide, the calcium oxide, the zirconium oxide and the titanium oxide is not less than 10nm, the pore volume of the pore diameter of 2-6nm is not more than 15% of the total pore volume, and the pore volume of the pore diameter of 6-40nm is not less than 75% of the total pore volume.

In the invention, in order to further improve the solubility of the precursor of the hydrodesulfurization catalytic active component in the prepared impregnation liquid and improve the performance of the finally prepared hydrogenation catalyst II, a phosphorus-containing substance is preferably added in the preparation process of the impregnation liquid, and the phosphorus-containing substance is preferably a phosphorus-containing inorganic acid and is further preferably at least one of phosphoric acid, hypophosphorous acid, ammonium phosphate and ammonium dihydrogen phosphate.

In the invention, the forming mode can be various existing forming methods, for example, extrusion molding or rolling ball molding. The extrusion molding can be performed according to the prior art, and the inorganic refractory component to be extruded and molded and the impregnation solution containing the metal component are uniformly mixed and then extruded into a required shape, such as a cylinder, a clover shape, a honeycomb shape and the like.

The method provided by the invention can be used for treating high-sulfur straight-run diesel oil or inferior secondary processing diesel oil, and producing an ultra-low-sulfur diesel oil product with the sulfur content of less than 10 mu g/g under relatively mild conditions, and the whole catalyst system has better stability and obviously improves the running period of the device.

Detailed Description

The invention is further described below by way of examples, but is not limited thereby.

In the following examples, the composition of the catalyst was calculated from the charge. The sulfur content of the diesel raw material is measured by adopting an X-ray fluorescence instrument of XOS company, and the measuring method comprises the following steps: ASTM-7039; the sulfur content of the diesel oil product is measured by adopting an EA5000 type instrument produced by Jena, and the test method comprises the following steps: SH-0689; the content of aromatic hydrocarbons was analyzed by near infrared spectroscopy. The specific surface area of the catalyst and the pore distribution, the pore diameter and the pore volume of the catalyst between 2 and 40nm are measured by a low-temperature nitrogen adsorption method (meeting the GB/T5816-1995 standard), and the pore distribution, the pore diameter and the pore volume of the catalyst between 100 and 300nm are measured by a mercury intrusion method. The average pore diameter of the catalyst was calculated according to the cylindrical pore model (average pore diameter ═ total pore volume × 4000/specific surface area).

In the examples, the hydrogenation catalyst I was a commercial RG-1 catalyst, which was produced by Changjingtie division of China petrochemical catalyst, Inc.

Hydrogenation catalysts S1, S2 and S3 were used in hydrogenation catalyst II in the examples, and were prepared by the following methods, respectively:

the hydrogenation catalyst S1 used was prepared by the following method.

(1) Commercially available white carbon black (specific surface area: 220 m)²Per g, the average pore diameter is 12.7nm) and basic cobalt carbonate powder are uniformly mixed and then roasted at 400 ℃ for 3h to obtain the cobalt-containing inorganic refractory powder.

Wherein the amount of basic cobalt carbonate used corresponds to a cobalt (calculated as cobalt oxide) content of the catalyst of 22.0 wt.%.

(2) Adding a certain amount of MoO₃Adding the basic cobalt carbonate and the propanol into a phosphoric acid-containing aqueous solution respectively, heating and stirring until the basic cobalt carbonate and the propanol are completely dissolved, and then adding a certain amount of citric acid until the citric acid is completely dissolved to obtain an active metal-containing impregnation solution.

Wherein the mass ratio of the mole number of the propanol to the inorganic fire-resistant component is 0.01, and the mass of the citric acid is 2 wt% of the mass of the inorganic fire-resistant component.

(3) The impregnating solution and the inorganic refractory component are uniformly mixed, and then extruded into strips for forming. The oxidation state catalyst with the grain diameter of 1.6mm is prepared after drying for 3 hours at 200 ℃.

Wherein the impregnating solution and the cobalt-containing inorganic refractory powder are mixed in such a proportion that the content of molybdenum oxide is 55.0 wt%, the content of cobalt oxide is 30.0 wt%, and P is in the catalyst, based on the dry weight of the catalyst and calculated as an oxide₂O₅The content was 5% by weight, and the content of the inorganic refractory component was 10.0% by weight.

The catalyst is roasted for 3h at 400 ℃ to prepare the hydrogenation catalyst S1. The pore size distribution is analyzed by using low-temperature nitrogen adsorption and mercury porosimetry. The specific surface area of the hydrogenation catalyst S1 was 93.0m²(ii)/g, the pore diameter distribution was 2 to 40nm and 100-300nm, wherein the ratio of the pore volume of 2 to 40nm to the total pore volume was 88.5% (wherein the ratio of the pore volume of 2 to 4nm to the total pore volume was 8.9%), the ratio of the pore volume of 100-300nm to the total pore volume was 6.3%, the pore volume was 0.22mL/g, and the average pore diameter was 9.5 nm.

The hydrogenation catalyst S2 used in this example was prepared by the following method.

(1) Commercially available white carbon black (specific surface area: 220 m)²The average pore diameter is 12.7nm), and basic nickel carbonate powder are evenly mixed and then roasted for 3h at 500 ℃ to obtain the nickel-containing inorganic refractory powder.

Wherein the amount of basic nickel carbonate used corresponds to a nickel content (calculated as nickel oxide) of 16.0 wt.% in the catalyst.

(2) Adding a certain amount of MoO₃Adding basic nickel carbonate and butanol into the water solution containing phosphoric acid respectively, heating and stirring until the basic nickel carbonate and the butanol are completely dissolved, and then adding a certain amount of tartaric acid until the tartaric acid is completely dissolved to obtain the impregnation solution containing the active metal.

Wherein the mass ratio of the mole number of the butanol to the inorganic refractory component is 0.02, and the mass of the tartaric acid is 5 wt% of the mass of the inorganic refractory component.

(3) The impregnating solution and the inorganic refractory component are uniformly mixed, and then extruded into strips for forming. The oxidized catalyst with the particle size of 1.6mm is prepared by drying for 8h at 150 ℃.

Wherein the impregnating solution and the nickel-containing inorganic refractory powder are mixed in such a proportion that the content of molybdenum oxide, the content of nickel oxide and the content of P in the catalyst are 47.0 wt%, 25.0 wt% and 25.0 wt%, respectively, on the basis of the dry weight of the catalyst and on the basis of the oxide₂O₅The content was 8.0% by weight, and the content of the inorganic refractory component was 20.0% by weight.

The catalyst is roasted for 3h at 400 ℃ to prepare the hydrogenation catalyst S2. The pore size distribution is analyzed by using low-temperature nitrogen adsorption and mercury porosimetry. The specific surface area of the hydrogenation catalyst S2 was 155m²(ii)/g, the pore diameter distribution was 2 to 40nm and 100-300nm, wherein the ratio of the pore volume of 2 to 40nm to the total pore volume was 89.3% (wherein the ratio of the pore volume of 2 to 4nm to the total pore volume was 6.7%), the ratio of the pore volume of 100-300nm to the total pore volume was 7.4%, the pore volume was 0.31mL/g, and the average pore diameter was 8.0 nm.

The hydrogenation catalyst S3 used in this example was prepared by the following method.

(1) Commercially available zirconium hydroxide powder (specific surface area of 180 m) was added²The average pore diameter is 13.3nm), and basic nickel carbonate powder are evenly mixed and then roasted for 3h at 400 ℃ to obtain the nickel-containing inorganic refractory powder.

The amount of basic nickel carbonate used corresponds to a nickel content (calculated as nickel oxide) of 28.0% by weight of the catalyst.

(2) Respectively adding a certain amount of ammonium metatungstate, basic nickel carbonate and glycerol into a water solution containing phosphoric acid, heating and stirring until the ammonium metatungstate, the basic nickel carbonate and the glycerol are completely dissolved, then adding a certain amount of caproic acid until the caproic acid is completely dissolved, and obtaining an impregnation solution containing active metals.

Wherein the mass ratio of the mole number of the glycerol to the inorganic fire-resistant component is 0.01, and the mass of the caproic acid is 2.5 wt% of the mass of the inorganic fire-resistant component.

(3) The impregnating solution and the inorganic refractory component are uniformly mixed, and then extruded into strips for forming. The oxidation state catalyst with the grain diameter of 1.6mm is prepared after drying for 5 hours at 180 ℃.

Wherein the impregnating solution and the nickel-containing inorganic refractory powder are mixed in such a proportion that the content of tungsten oxide in the catalyst is 45.0%, the content of nickel oxide is 32.0% and P is calculated as oxide on the basis of the dry weight of the catalyst₂O₅The content was 3.0% by weight, and the content of the inorganic refractory component was 20.0% by weight.

The catalyst is roasted for 3h at 400 ℃ to prepare the hydrogenation catalyst S3. The pore size distribution is analyzed by using low-temperature nitrogen adsorption and mercury porosimetry. The specific surface area of the hydrogenation catalyst S3 was 109m²(ii)/g, the pore diameter distribution was 2 to 40nm and 100-300nm, wherein the proportion of the pore volume of 2 to 40nm to the total pore volume was 85.6% (wherein the proportion of the pore volume of 2 to 4nm to the total pore volume was 6.8%), the proportion of the pore volume of 100-300nm to the total pore volume was 12.3%, the pore volume was 0.29mL/g, and the average pore diameter was 10.6 nm.

The hydrogenation catalyst I used in the comparative example adopts a commercial brand of RG-1, and the hydrogenation catalyst II has commercial brands of RS-2100 and RS-2200, which are produced by China petrochemical catalyst division.

The properties of the raw oils used in the examples and comparative examples are shown in Table 1.

TABLE 1 Properties of the stock oils

Example 1

Taking middle-east high-sulfur straight-run diesel oil fraction as diesel oil raw oil 1, pressurizing the diesel oil raw oil 1, mixing the diesel oil raw oil with hydrogen-containing material flow, feeding the mixture into a hydrogenation reactor, sequentially passing through a first hydrogenation reaction zone and a second hydrogenation reaction zone, and respectively contacting with a hydrogenation catalyst I and a hydrogenation catalyst S1 to carry out deep hydrodesulfurization reaction, wherein the hydrogen partial pressure at the inlet of the reactor is 4.8MPa, the reaction temperature of the first hydrogenation reaction zone is 310 ℃, the reaction temperature of the second hydrogenation reaction zone is 345 ℃, and the liquid hourly volume space velocity of the first hydrogenation reaction zone is 20.0h^-1The liquid hourly space velocity of the second hydrogenation reaction zone was 2.5h^-1The hydrogen-oil volume ratio of the first hydrogenation reaction zone and the second hydrogenation reaction zone is 200.

And performing gas-liquid separation on the effluent of the hydrogenation reactor in a high-pressure separator, desulfurizing the gas-phase material flow obtained by separation in the high-pressure separator, circulating the gas-phase material flow back to the inlet of the reactor, further performing gas-liquid separation on the liquid-phase material flow obtained by separation in the high-pressure separator in a low-pressure separator, fractionating the liquid-phase material flow obtained by the low-pressure separator in a fractionating tower, producing naphtha fraction at the tower top and ultralow-sulfur diesel fraction at the tower bottom. The main properties of the product are shown in table 2.

Comparative example 1a

Taking middle-east high-sulfur straight-run diesel oil fraction as diesel oil raw oil 1, boosting the pressure of the diesel oil raw oil 1, then feeding the diesel oil raw oil 1 and mixed hydrogen into a reactor filled with a hydrofining catalyst RS-2200, and carrying out deep hydrodesulfurization reaction at the reactor, wherein the hydrogen partial pressure at the inlet of the reactor is 4.8MPa, the reaction temperature is 345 ℃, and the hourly volume space velocity of the raw oil is 2.5h^-1And the volume ratio of hydrogen to oil under the standard state is 200.

The gas-liquid separation and liquid phase stream fractionation schemes were the same as in example 1, and the main product properties are shown in table 2.

Comparative example 1b

A middle-east high-sulfur straight-run diesel oil fraction is used as raw oil 1, the process flow is the same as that in example 1, and the difference is that a hydrogenation catalyst II in the comparative example adopts a hydrofining catalyst RS-2200.

The hydrogen partial pressure at the inlet of the reactor is 4.8MPa, the reaction temperature of the first hydrogenation reaction zone is 320 ℃, the reaction temperature of the second hydrogenation reaction zone is 353 ℃, and the liquid hourly volume space velocity of the first hydrogenation reaction zone is 20.0h^-1The liquid hourly space velocity of the second hydrogenation reaction zone was 2.5h^-1The hydrogen-oil volume ratio of the first hydrogenation reaction zone and the second hydrogenation reaction zone is 200. The main properties of the product are shown in table 2.

TABLE 2

Product Properties	Example 1	Comparative example 1a	Comparative example 1b
				Sulfur content, μ g/g	7	28	7
Nitrogen content,. mu.g/g	0.2	0.8	0.2
				Sulfur content of initial reaction product	7	28	7
Sulfur content of the product after 1000 hours	10	39	13
				Product sulfur content after 2000 hours	12	51	21

Example 2

A mixed diesel oil fraction is used as diesel oil raw material oil 2, the diesel oil raw material oil 2 is pressurized and then mixed with a hydrogen-containing material flow, the mixture enters a hydrogenation reactor, and sequentially passes through a first hydrogenation reaction zone and a second hydrogenation reaction zone to be respectively contacted with a hydrogenation catalyst I and a hydrogenation catalyst S2 for deep hydrodesulfurization reaction, the hydrogen partial pressure at the inlet of the reactor is 6.4MPa, the reaction temperature of the first hydrogenation reaction zone is 320 ℃, the reaction temperature of the second hydrogenation reaction zone is 355 ℃, and the liquid hourly volume space velocity of the first hydrogenation reaction zone is 18.0h^-1The liquid hourly space velocity of the second hydrogenation reaction zone was 1.5h^-1The hydrogen-oil volume ratio of the first hydrogenation reaction zone and the second hydrogenation reaction zone is 400.

And performing gas-liquid separation on the effluent of the hydrogenation reactor in a high-pressure separator, desulfurizing the gas-phase material flow obtained by separation in the high-pressure separator, circulating the gas-phase material flow back to the inlet of the reactor, further performing gas-liquid separation on the liquid-phase material flow obtained by separation in the high-pressure separator in a low-pressure separator, fractionating the liquid-phase material flow obtained by the low-pressure separator in a fractionating tower, producing naphtha fraction at the tower top and ultralow-sulfur diesel fraction at the tower bottom. The main properties of the product are shown in table 3.

Comparative example 2a

A mixed diesel oil fraction is used as diesel oil raw oil 2, the pressure of the diesel oil raw oil 2 is boosted and then the diesel oil raw oil 2 and mixed hydrogen enter a reactor filled with a hydrofining catalyst RS-2100, and thenThe deep hydrodesulfurization reaction is carried out, the hydrogen partial pressure at the inlet of the reactor is 6.4MPa, the reaction temperature is 355 ℃, and the hourly space velocity of the raw oil is 1.5h^-1And the volume ratio of hydrogen to oil under the standard state is 400.

The gas-liquid separation and liquid phase stream fractionation schemes were the same as in example 2, and the main product properties are shown in table 3.

Comparative example 2b

A mixed diesel oil fraction is used as raw oil 2, the process flow is the same as that in example 2, and the difference is that a hydrogenation catalyst II in the comparative example adopts a hydrofining catalyst RS-2100.

The hydrogen partial pressure at the inlet of the reactor is 6.4MPa, the reaction temperature of the first hydrogenation reaction zone is 326 ℃, the reaction temperature of the second hydrogenation reaction zone is 365 ℃, and the liquid hourly space velocity of the first hydrogenation reaction zone is 18.0h^-1The liquid hourly space velocity of the second hydrogenation reaction zone was 1.5h^-1The hydrogen-oil volume ratio of the first hydrogenation reaction zone and the second hydrogenation reaction zone is 400. The main properties of the product are shown in table 3.

TABLE 3

Product Properties	Example 2	Comparative example 2a	Comparative example 2b
				Sulfur content, μ g/g	6	33	6
Nitrogen content,. mu.g/g	0.8	7.2	1.1
				Sulfur content of initial reaction product	6	33	6
Sulfur content of the product after 1000 hours	10	51	15
				Product sulfur content after 2000 hours	14	64	25

Example 3

A mixed diesel oil fraction is used as diesel oil raw material 3, the diesel oil raw material 3 is pressurized and then mixed with a hydrogen-containing material flow to enter a hydrogenation reactor, the mixture sequentially passes through a first hydrogenation reaction zone and a second hydrogenation reaction zone and is respectively contacted with a hydrogenation catalyst I and a hydrogenation catalyst S3 to carry out deep hydrodesulfurization reaction, the hydrogen partial pressure at the inlet of the reactor is 7.2MPa, the reaction temperature of the first hydrogenation reaction zone is 320 ℃, the reaction temperature of the second hydrogenation reaction zone is 360 ℃, and the liquid hourly volume space velocity of the first hydrogenation reaction zone is 15.0h^-1The liquid hourly space velocity of the second hydrogenation reaction zone was 1.0h^-1The hydrogen-oil volume ratio of the first hydrogenation reaction zone and the second hydrogenation reaction zone was 600.

And performing gas-liquid separation on the effluent of the hydrogenation reactor in a high-pressure separator, desulfurizing the gas-phase material flow obtained by separation in the high-pressure separator, circulating the gas-phase material flow back to the inlet of the reactor, further performing gas-liquid separation on the liquid-phase material flow obtained by separation in the high-pressure separator in a low-pressure separator, fractionating the liquid-phase material flow obtained by the low-pressure separator in a fractionating tower, producing naphtha fraction at the tower top and ultralow-sulfur diesel fraction at the tower bottom. The main properties of the product are shown in table 4.

Comparative example 3a

A mixed diesel oil fraction is used as diesel raw oil 3, the diesel raw oil 3 is pressurized and then enters a reactor filled with a hydrofining catalyst RS-2100 together with mixed hydrogen, deep hydrodesulfurization reaction is carried out in the reactor, the hydrogen partial pressure at the inlet of the reactor is 7.2MPa, the reaction temperature is 360 ℃, and the hourly space velocity of the raw oil is 1.0h^-1And the volume ratio of hydrogen to oil under the standard state is 600.

The gas-liquid separation and liquid phase stream fractionation schemes were the same as in example 3, and the main product properties are shown in table 4.

Comparative example 3b

A mixed diesel oil fraction is used as raw oil 3, the process flow is the same as that in example 3, and the difference is that a hydrogenation catalyst II in the comparative example adopts a hydrofining catalyst RS-2100.

The hydrogen partial pressure at the inlet of the reactor is 6.4MPa, the reaction temperature of the first hydrogenation reaction zone is 325 ℃, the reaction temperature of the second hydrogenation reaction zone is 370 ℃, and the liquid hourly volume space velocity of the first hydrogenation reaction zone is 15.0h^-1The liquid hourly space velocity of the second hydrogenation reaction zone was 1.0h^-1The hydrogen-oil volume ratio of the first hydrogenation reaction zone and the second hydrogenation reaction zone was 600. The main properties of the product are shown in table 4.

TABLE 4

Product Properties	Example 3	Comparative example 3a	Comparative example 3b
				Sulfur content, μ g/g	9	38	9
Nitrogen content,. mu.g/g	1.9	23	3.6
				Sulfur content of initial reaction product	9	38	9
Sulfur content of the product after 1000 hours	13	57	19
				Product sulfur content after 2000 hours	17	71	31

As can be seen from tables 1 to 4, the methods of examples 1 to 3 can produce ultra-low sulfur diesel oil products having very low sulfur content under mild reaction conditions for straight-run diesel oil, mixed oil of straight-run diesel oil, catalytic diesel oil and residual hydrogenated diesel oil, and mixed oil of catalytic diesel oil and coker diesel oil. The overall catalyst system of the examples had better stability than the comparative examples 1a to 3 a. Comparing examples 1 to 3 with comparative examples 1b to 3b, it can be seen that when the sulfur content of the product is the same, the reaction temperature can be lower by the method of the example, and the poorer the feedstock oil property, the larger the reduction of the reaction temperature by the method of the example. In addition, the method of the embodiment has better stability of the catalyst, and after the same running time, the sulfur content of the products of the embodiments 1 to 3 is far lower than that of the products of the comparative examples 1b to 3 b.

The method provided by the invention can be used for producing the ultra-low sulfur diesel under a more moderate reaction condition, and the catalyst has better stability.

Claims

1. A production method of ultra-low sulfur diesel oil is characterized in that raw diesel oil and hydrogen-containing material flow are mixed and then sequentially pass through a first hydrogenation reaction zone and a second hydrogenation reaction zone, wherein the first hydrogenation reaction zone is filled with a hydrogenation catalyst I, the second hydrogenation reaction zone is filled with a hydrogenation catalyst II, and the ultra-low sulfur diesel oil with the sulfur content of less than 10 mu g/g is obtained after gas-liquid separation and liquid phase material fractionation of materials after hydrogenation reaction;

the reaction temperature of the first hydrogenation reaction zone is lower than that of the second hydrogenation reaction zone, and the reaction temperature of the first hydrogenation reaction zone is 5-80 ℃ lower than that of the second hydrogenation reaction zone;

the hydrogenation catalyst I is a supported non-noble metal catalyst and comprises a carrier and at least one VIII group metal element and at least one VIB group metal element which are supported on the carrier, wherein the VIII group metal element content is 0.5-5 wt% and the VIB group metal element content is 1-10 wt% in terms of oxides based on the total amount of the hydrogenation catalyst I;

2. The process according to claim 1, characterized in that the hydrodesulphurization catalytically active components are elements of group VIII metals and elements of group VIB metals; wherein, in the hydrogenation catalyst II, the content of the VIII group metal element is 15-35 wt% based on the dry weight of the catalyst and calculated by oxide; the content of the group VIB metal elements is 35-75 wt%.

3. The process according to claim 2, wherein the hydrogenation catalyst II contains 20 to 30 wt.% of the group VIII metal element, calculated as the oxide and based on the dry weight of the catalyst; the content of the VIB group metal element is 40-65 wt%; the VIII group metal element is selected from at least one of iron, cobalt, nickel, ruthenium, rhodium and palladium, and the VIB group metal element is selected from at least one of chromium, molybdenum and tungsten.

4. The process according to claim 1 or 2, wherein the hydrodesulfurization catalytic active component contained in the inorganic refractory component is a group VIII metal element, and the content of the group VIII metal element contained in the inorganic refractory component is 60 to 90% of the total content of the group VIII metal elements in the catalyst.

5. The process as claimed in claim 1, wherein the hydrogenation catalyst II has a pore volume of 2-40nm pore diameter of 75-90% of the total pore volume and a pore volume of 100-300nm pore diameter of 5-15% of the total pore volume.

6. The process according to claim 1, wherein the hydrogenation catalyst II has a specific surface area of from 70 to 200m²Per g, pore volume of 0.15-0.6mL/g, average pore diameter of 5-25 nm.

7. The process of claim 6, wherein the pore volume in the hydrogenation catalyst II is no more than 10% of the total pore volume in the range of 2-4 nm.

8. The process of claim 1 wherein the inorganic refractory component is present in an amount of from 5 to 40 wt.%, based on the dry weight of hydrogenation catalyst II.

9. The process of claim 8 wherein the inorganic refractory component is present in an amount of from 10 to 30 wt.%, based on the dry weight of hydrogenation catalyst II.

10. The method of claim 1, wherein the mass ratio of carboxylic acid to inorganic refractory component on a dry basis is from 0.002 to 0.1: 1.

11. the method of claim 10, wherein the mass ratio of carboxylic acid to inorganic refractory component on a dry basis is from 0.02 to 0.06: 1; the carboxylic acid is selected from at least one of C1-18 monobasic saturated carboxylic acid, C7-10 phenyl acid, citric acid, adipic acid, malonic acid, succinic acid, maleic acid and tartaric acid.

12. The method according to claim 1, wherein the ratio of the number of moles of alcohol to the dry mass of the inorganic refractory component is from 0.005 to 0.03: 1.

13. the method of claim 12, wherein the ratio of moles of alcohol to dry mass of the inorganic refractory component is from 0.01 to 0.02: 1; the alcohol is at least one selected from C1-18 monohydric saturated alcohol, ethylene glycol, polyethylene glycol, glycerol, polyglycerol, erythritol, pentaerythritol, xylitol, sorbitol and trimethylolethane.

14. The process of claim 1 wherein hydrogenation catalyst II contains phosphorus in an amount P based on the dry weight of hydrogenation catalyst II₂O₅The content of the phosphorus element is 0.8-10 wt%.

15. The method of claim 14, wherein the elemental phosphorus is present in an amount of 1 to 8 wt.%.

16. The process of claim 1, wherein in the first hydrogenation reaction zone: the reaction temperature is 260 ℃ and 320 ℃, and the volume space velocity is 8.0-30.0h^-1The hydrogen partial pressure is 2.0-10.0MPa, and the volume ratio of hydrogen to oil is 100-1000: 1.

17. The process of claim 1 wherein in the second hydrogenation reaction zone: the reaction temperature is 260 ℃ and 420 ℃, and the volume space velocity is 0.4-4.0h^-1The hydrogen partial pressure is 2.0-10.0MPa, and the volume ratio of hydrogen to oil is 100-1000: 1.

18. The process of claim 1 wherein in the second hydrogenation reaction zone: the reaction temperature is 320 ℃ and 400 ℃, and the volume space velocity is 0.6-3.0h^-1The hydrogen partial pressure is 4.0-8.0MPa, and the volume ratio of hydrogen to oil is 300-600: 1.

19. The process of claim 1 wherein the reaction temperature in the first hydrogenation reaction zone is 20 to 80 ℃ lower than the reaction temperature in the second hydrogenation reaction zone.

20. A method according to claim 1, wherein the total sulfur content of the diesel feed oil is not more than 30000 μ g/g, the nitrogen content is not more than 3000 μ g/g, the total aromatics content is not more than 80 wt%, and the distillation range is less than 380 ℃.

21. The process of claim 1 wherein the second hydrogenation reaction zone is provided with a hydrogenation reactor or a plurality of hydrogenation reactors;

when a plurality of hydrogenation reactors are arranged in the second hydrogenation reaction zone, a heat exchanger is arranged between the reactors so as to adjust the inlet temperature of a single reactor.