CN111849548B

CN111849548B - Method for producing clean diesel oil

Info

Publication number: CN111849548B
Application number: CN201910363283.9A
Authority: CN
Inventors: 葛泮珠; 丁石; 习远兵; 鞠雪艳; 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: 2019-04-30
Filing date: 2019-04-30
Publication date: 2022-04-12
Anticipated expiration: 2039-04-30
Also published as: CN111849548A

Abstract

The invention relates to the technical field of oil refining and discloses a method for producing clean diesel oil. The method comprises the following steps: carrying out contact reaction on a diesel raw material and hydrogen with a hydrofining catalyst in a first reaction zone to obtain a first reaction zone effluent, wherein the first reaction zone effluent enters a second reaction zone without separation, and is subjected to contact reaction with a hydro-upgrading catalyst in the second reaction zone to obtain a second reaction zone effluent, and fractionating the second reaction zone effluent; the distillation range of the diesel raw material is 140-390 ℃, the sulfur content is 1000-15000 mu g/g, the nitrogen content is 50-3000 mu g/g, and the aromatic hydrocarbon content is 10-80 wt%. The method provided by the invention can produce the ultra-low sulfur diesel with less than 7 percent of polycyclic aromatic hydrocarbon and less than l0 mu g/g of sulfur content by using the specific hydrofining catalyst, can effectively prolong the whole operation period of the device and realize long-period operation.

Description

Method for producing clean diesel oil

Technical Field

The invention relates to the technical field of oil refining, in particular to a method for producing clean diesel oil.

Background

With the increasing importance of people on the quality of the ecological environment, the production of clean diesel oil is concerned more and more. In recent years new fuel standards and environmental regulations in many countries of the world have set increasingly stringent standards for automotive diesel. 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. Although the specifications of diesel oil products of various countries are different, ultralow-sulfur and low-aromatic diesel oil with lower sulfur content and polycyclic aromatic hydrocarbon content is a main target pursued by oil refining enterprises all over the world.

The current technology for producing clean diesel oil with low sulfur, low aromatic hydrocarbon and high cetane number must increase the operation severity, and the measures usually adopted include increasing the reaction temperature, increasing the partial pressure of reaction hydrogen, reducing the space velocity and the like. However, the increase of the reaction temperature not only seriously affects the service life of the catalyst and shortens the operation period of the device, but also the aromatic hydrocarbon saturation reaction is a reaction limited by thermodynamic equilibrium, and the content of the aromatic hydrocarbon in the product can be increased along with the increase of the reaction temperature under a certain reaction pressure. The high hydrogen partial pressure puts more demands on the equipment, which leads to a great increase in production cost. Reducing the volumetric space velocity means reducing the plant throughput. The difficulty of treating the diesel oil fraction is further increased along with the development of the processing raw materials to the heavy state and the increasing proportion of the high-sulfur crude oil. The method for improving the operation severity by adopting the prior art can bring the problems of improving the operation cost, shortening the operation period, reducing the aromatic hydrocarbon saturation rate of the product and the like. Therefore, it has been difficult to achieve the product quality requirements for clean diesel fuels using conventional hydrofinishing techniques.

Research shows that the pore structure of the catalyst has great influence on the reaction performance, and the catalyst should have proper pore structure to adapt to the diffusion of reactants. Therefore, many patents and research have been directed to the development and study of vectors. With the deterioration of the hydrogenation raw material, the size of reactant molecules is gradually increased, and a carrier with a larger pore channel structure is required to better meet the requirement of reactant diffusion. Common methods for increasing pore size mainly include the use of different pseudoboehmite mixtures (e.g., CN1488441A), the use of pore-expanding agents (e.g., CN1160602A, US4448896, CN1055877C, etc.), and the like. For example, CN101450327A is to heat treat monohydrate alumina at the temperature of 150-300 ℃, mix the monohydrate alumina with one or more pore-expanding agents selected from graphite, stearic acid, sodium stearate and aluminum stearate, knead the mixture evenly, dry the mixture at the temperature of 100-150 ℃ and then bake the mixture at the temperature of 700-1000 ℃ to obtain the alumina. In the above pore-expanding method, the pore-expanding agent and the pseudo-boehmite are not uniformly mixed, so that the pore-expanding effect is not good, and the addition of the pore-expanding agent also increases the cost. CN1087289A discloses a preparation method of a macroporous alumina carrier. The method uses pseudo-boehmite containing at room temperature to be instantly placed in a high temperature atmosphere with the high temperature range of 500-650 ℃, and the temperature is kept at the high temperature for 2-4 hours. The method uses the water which is rapidly evaporated at high temperature to expand the pores of the carrier, but the activity of the hydrogenation catalyst prepared by the carrier needs to be further improved.

Disclosure of Invention

The invention aims to provide a method for producing clean diesel oil on the basis of the prior art, and aims to solve the problems of harsh operating conditions, low airspeed and short service life of a catalyst when the ultra-low sulfur clean diesel oil is produced in the prior art.

In order to achieve the above object, the present invention provides a method for producing clean diesel, comprising: carrying out contact reaction on a diesel raw material and hydrogen and a hydrofining catalyst in a first reaction zone to obtain an effluent of the first reaction zone, wherein the hydrofining catalyst contains an inorganic refractory component, a hydrodesulfurization catalytic active component and carboxylic acid; the inorganic refractory component contains at least one of silicon oxide, magnesium oxide, calcium oxide, zirconium oxide and titanium oxide and part of hydrodesulfurization catalytic active component;

the hydrofining catalyst 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 effluent of the first reaction zone enters a second reaction zone without separation, and is subjected to contact reaction with a hydro-upgrading catalyst in the second reaction zone to obtain the effluent of the second reaction zone, and the effluent of the second reaction zone is fractionated;

the distillation range of the diesel raw material is 140-390 ℃, the sulfur content is 1000-15000 mu g/g, the nitrogen content is 50-3000 mu g/g, and the aromatic hydrocarbon content is 10-80 wt%.

By the technical scheme, the invention can produce the ultra-low sulfur diesel with less than 7 percent of polycyclic aromatic hydrocarbon and less than l0 mug/g of sulfur, can effectively prolong the whole operation period of the device and realize long-period operation.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a method for producing clean diesel oil, which comprises the following steps: the method comprises the steps of carrying out contact reaction on a diesel raw material and hydrogen with a hydrofining catalyst in a first reaction zone to obtain a first reaction zone effluent, enabling the first reaction zone effluent to enter a second reaction zone without separation, carrying out contact reaction with a hydro-upgrading catalyst in the second reaction zone to obtain a second reaction zone effluent, and fractionating the second reaction zone effluent.

In the invention, the distillation range of the diesel raw material is 140-390 ℃, the sulfur content is 1000-15000 mu g/g, the nitrogen content is 50-3000 mu g/g, and the aromatic hydrocarbon content is 10-80 wt%. Preferably, the nitrogen content of the diesel feedstock is from 50 to 800 μ g/g. The diesel feedstock may be selected from at least one of straight-run diesel, catalytic cracking diesel and coker diesel.

In the present invention, the hydrofining catalyst contains an inorganic refractory component, a hydrodesulfurization catalytic active component and a carboxylic acid; the inorganic refractory component contains at least one of silicon oxide, magnesium oxide, calcium oxide, zirconium oxide and titanium oxide and part of hydrodesulfurization catalytic active component; the hydrofining catalyst 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 inventors of the present invention found in their studies that the introduction of a carboxylic acid compound into a hydrorefining catalyst can protect the active component of the hydrorefining catalyst and improve the activity of the hydrorefining catalyst. Therefore, the effect of protecting the active component of the hydrorefining catalyst and improving the activity of the hydrorefining catalyst can be obtained by introducing the carboxylic acid into the hydrorefining catalyst, and the amount of the carboxylic acid added is not particularly limited. According to a preferred embodiment of the invention, the weight ratio, on a dry basis, of the carboxylic acid to the inorganic refractory component is between 0.1 and 0.8: 1, preferably 0.2 to 0.6: 1.

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 hydrorefining catalyst, the hydrorefining catalyst further contains a phosphorus element, preferably P₂O₅Exist in the form of (1). Preferably, based on the dry weight of the hydrofinishing catalyst 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 hydrofining catalyst is a shaped catalyst, and the shape of the hydrofining catalyst is preferably a cylinder, a clover or a honeycomb.

The hydrofining catalyst of the invention has the pore passage with the size of 100-300nm, which can provide a larger place for the diffusion of reactants, promotes the accessibility of the reactants and an active center, not only can improve the activity of the catalyst, but also can effectively maintain the high activity of the catalyst for a long time, thereby greatly improving the service life of the catalyst and prolonging the operation period.

In the course of research, the inventors of the present invention found that the carrier of the hydrogenation catalyst is generally obtained by extruding a carrier precursor (such as pseudo-boehmite powder) with a peptizing agent and an extrusion aid to form a strip, and then drying and calcining the strip. Because the hydrogenation reaction requires a catalyst with a larger pore structure, and before calcination, the pores are generally concentrated at 2-12nm, so that the pore size of the catalyst is generally increased by calcining the molded carrier to increase the pore size of the carrier, the pores of the calcined carrier are generally concentrated at 2-100nm, the average pore size of the carrier is increased, and it is generally considered that the pore size is larger as the calcination temperature is higher. However, the inventors of the present invention found in their studies that collapse condensation occurs in the pore walls of the carrier with an increase in the calcination temperature. Although pore wall condensation may increase the average pore size of the support, the condensed pore walls may reduce the utilization of alumina, thereby reducing the catalytic activity of the catalyst. According to the preparation method of the hydrofining catalyst provided by the invention, the precursor of the carrier is preferably roasted before extrusion molding, so that on one hand, the number of hydroxyl groups in the precursor particles of the carrier can be reduced through heat treatment, the probability of channel condensation is reduced, and the aperture of the catalyst is increased. In the second aspect, the molded catalyst does not need to be treated at a higher temperature, and the pore wall of the carrier does not need to be subjected to excessive condensation, so that the utilization rate of the carrier is improved. In the third aspect, the carrier precursor is subjected to heat treatment before molding, and partial secondary particles are also condensed, so that the size of the formed alumina particles tends to be single, and the pore channels in the molded catalyst are more uniform, which is beneficial to the diffusion of reactants. Especially for heavier and inferior oil products, is more effective than the conventional catalyst.

The inventors of the present invention have found that the conventional impregnation method produces hydrofinishing catalysts having a low metal loading, typically less than 10% of group VIII metals and typically less than 35% of group VIB metals. This limits the number of active metal sites of the hydrofinishing catalyst, which do not reach higher levels of activity. The catalyst prepared by the kneading method can improve the loading of active metal in the catalyst, but the hydrofining activity of the catalyst is not high, and the utilization rate of the active metal is low. Currently, hydrofinishing catalysts are generally not prepared by this method. In the present invention, a portion of the hydrodesulfurization catalytically active component, and more preferably a portion of the group VIII metal, is mixed into a support precursor and calcined to form the inorganic refractory powder. And then mixing the impregnation liquid containing the residual active metal with the inorganic refractory powder, thereby improving the content of active components in the catalyst and further improving the hydrofining performance of the catalyst.

In the present invention, the hydrorefining catalyst may not contain a pore-expanding agent such as carbon black, graphite, stearic acid, sodium stearate, or aluminum stearate, or may not contain a component such as a surfactant, and may directly satisfy the demand for the reactivity.

The silicon oxide, the magnesium oxide, the calcium oxide, the zirconium oxide and the 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 inorganic refractory components have weak acting force with other active components of the hydrofining catalyst, so that the growth of an active phase of the hydrofining catalyst can be promoted, and the performance of the hydrofining catalyst is further promoted.

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 hydrofining catalyst and the pore distribution, the pore diameter and the pore volume of 2-40nm 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 100-300nm are measured by a mercury intrusion method. The pore volume of the hydrorefining catalyst with the pore diameter less than 100nm is measured by a low-temperature nitrogen adsorption method, the pore volume of the hydrorefining catalyst with the pore diameter more than 100nm is measured by a mercury intrusion method, and the pore volume of the hydrorefining catalyst 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 hydrofinishing catalystIs 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. The specific surface area, the pore volume and the average pore diameter are measured after the hydrofining 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.

According to the invention, the hydrogen desulfurization catalytically active component may be a component of an active component that is currently available for hydrofinishing catalysts, for example, the active component may include group VIII metal elements and group VIB metal elements. Wherein the content of the active component may also vary within wide limits, it is preferred that the content of group VIII metal elements in the hydrofinishing catalyst is from 15 to 35 wt.%, preferably from 20 to 30 wt.%, based on the dry weight of the catalyst and calculated as oxide; the content of group VIB metal elements is from 35 to 75% by weight, preferably from 40 to 65% by weight.

According to a preferred embodiment of the present invention, 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.

The inventors of the present invention have found in their studies that, by preferably including a part of the group VIII metal element in the inorganic refractory component, the content of the active component in the hydrorefining catalyst can be further increased, thereby further improving the hydrorefining performance of the catalyst. While the amount ratio of the group VIII metal element contained in the inorganic refractory component is not particularly limited and may be selected from a wide range, it is preferable that the content of the partial group VIII metal element is 60 to 90% of the total content of the group VIII metal elements.

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

Here, the dry weight of the inorganic refractory powder is a weight measured by calcining a sample at 600 ℃ for 4 hours, and the dry weight of the hydrorefining catalyst is a weight measured by calcining a sample at 400 ℃ for 3 hours. The dry basis weights appearing hereinafter are equally applicable to this definition. That is, in the case where there is no reverse explanation, the dry weight of the inorganic refractory powder as described herein means the weight determined by calcining a sample at 600 ℃ for 4 hours, and the dry weight of the hydrofinishing catalyst is determined by calcining a sample at 400 ℃ for 3 hours. It is known to those skilled in the art that organic acids contained in a hydrorefining catalyst are decomposed and volatilized at high temperatures when calculated on a dry weight basis, and therefore, the content of the organic acids is not calculated on a dry weight basis.

Preferably, the preparation method of the hydrofining catalyst comprises the following steps:

(1) mixing and roasting a precursor containing at least one of silicon oxide, magnesium oxide, calcium oxide, zirconium oxide and titanium oxide and a precursor of a part of hydrodesulfurization catalytic active component to obtain an inorganic refractory component;

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

(3) and mixing the inorganic refractory component with the impregnation liquid, and molding and drying the obtained mixture to obtain the hydrofining catalyst.

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; the precursors of the VIII group metal elements and the VIB group metal elements are used in such amounts that the contents of the VIII group metal elements and the VIB group metal elements are respectively the contents as described above based on the dry weight of the catalyst and calculated by oxides, and the selection of the specific elements is also performed as described above.

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.

The inventor of the present invention found in research that, preferably, by preparing a part of the precursor of the group VIII metal element into the inorganic refractory component and preparing an impregnation solution by using the rest of the precursor of the group VIII metal element and the precursor of the group VIB metal element together to impregnate the inorganic refractory component, the content of the active component in the hydrorefining catalyst can be further increased, thereby further improving the hydrorefining performance of the catalyst. While the amount ratio of the precursor of the group VIII metal element used for preparing the inorganic refractory component is not particularly limited and may be selected from a wide range, it is preferable that the amount of the partial precursor of the group VIII metal element is 60 to 90% of the total amount of the precursor of the group VIII metal element in step (1).

According to the invention, in the step (1), the precursor of silica, magnesia, calcia, zirconia, titania can be various substances which can provide silica, magnesia, calcia, zirconia, titania under the roasting condition, for example, the silica precursor can be silica sol, silica white, silica dioxide, 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.

In step (3), the inorganic refractory component is used in an amount such that the content of the inorganic refractory component in the hydrofinishing catalyst is 5 to 40% by weight, preferably 10 to 30% by weight, based on the dry weight of the hydrofinishing catalyst.

In step (2), the amount and selection of the carboxylic acid are described in detail above, and are not repeated here.

According to the invention, the carboxylic acid substances are introduced into the impregnation liquid, so that the hydrodesulfurization catalytic active component can be effectively protected, and the forming of the hydrofining catalyst can be promoted, so that the performance of the hydrofining catalyst can be effectively improved.

In order to further improve the performance of the finally prepared hydrofining catalyst, the average pore diameters of the silicon oxide, the magnesium oxide, the calcium oxide, the zirconium oxide and the titanium oxide precursors are not less than 10nm, the pore volume of the pore diameters of 2-6nm accounts for no more than 15% of the total pore volume, and the pore volume of the pore diameters of 6-40nm accounts for no less than 75% of the total pore volume.

According to the present invention, in order to further improve the solubility of the precursor of the hydrodesulfurization catalytic active component in the prepared impregnation solution and improve the performance of the finally prepared hydrofining catalyst, a phosphorus-containing substance is preferably added during the preparation of the impregnation solution, 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. Further preferably, the phosphorus-containing substance is used in such an amount that the final preparation is carried outBased on the weight on a dry basis and expressed as P₂O₅The content of the phosphorus element is 0.8 to 10% by weight, preferably 1 to 8% by weight, more preferably 2 to 8% by weight.

According to a preferred embodiment of the invention, in the preparation of the impregnation solution, the organic carboxylic acid compound and the precursors containing the group VIB metal element and the group VIII metal element are added to the aqueous solution of the phosphorus-containing substance, and then stirred at 40-100 ℃ for 1-8h until all the organic carboxylic acid compound and the precursors are dissolved. The order of addition of the organic carboxylic acid compound, the phosphorus-containing substance, and the metal element precursor may be interchanged.

According to the invention, in the step (1), the roasting conditions can be selected within a wide range, and preferably, the roasting temperature is 300-900 ℃, preferably 400-700 ℃; the roasting time is 1-15h, preferably 3-8 h.

According to the present invention, in the step (3), the drying conditions can be selected within a wide range, and preferably, the drying temperature is 50-250 ℃, preferably 100-200 ℃; the drying time is 2-10h, preferably 3-8 h.

According to the invention, the forming mode can be various existing forming methods, such as extrusion molding and 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.

According to a preferred embodiment of the present invention, in order to prevent coking and metal poisoning of the hydrotreating catalyst by coking precursors such as olefins and gums in the diesel feedstock, a hydrogenation protecting agent is loaded upstream of the hydrotreating catalyst in an amount of 1 to 20% by volume of the hydrotreating catalyst. The hydroprotectants are commercially available. For example, the hydrogenation protective agent can be a hydrogenation protective agent with the trade mark RG-30A or RG-30B which is purchased from the company of petrochemical industry, Inc. in China. Preferably, the hydroprotectant comprises: 1.0-5.0 wt% nickel oxide, 5.5-10.0 wt% molybdenum oxide and 85-93.5 wt% gamma-alumina carrier with diplopore distribution.

In the invention, the hydrofining catalyst can be sulfurized before use, and the sulfurization conditions of the hydrofining catalyst can be the conditions used for sulfurizing the hydrofining catalyst, such as 0.1-15MPa of sulfurization pressure and 0.5-20h of volume space velocity^-1The volume ratio of hydrogen to oil is 100-: 1. the vulcanization mode is not particularly limited, and may be dry vulcanization or wet vulcanization.

In the present invention, the effluent from the first reaction zone comprises a gas phase stream and a liquid phase stream, preferably the liquid phase stream has a sulfur content of 20 to 200. mu.g/g and a nitrogen content of 0 to 50. mu.g/g, more preferably the liquid phase stream has a sulfur content of 40 to 100. mu.g/g and a nitrogen content of 10 to 30. mu.g/g.

In the present invention, the hydro-upgrading catalyst may be prepared according to the prior art or may be obtained commercially. For example, the product may be one or more of RIC-3, RIC-2 and RHC-1, which are commercially available from Changjingtie division of petrochemical catalyst, China.

Preferably, the hydro-upgrading catalyst comprises a catalyst carrier and a hydrogenation active component loaded on the catalyst carrier, wherein the hydrogenation active component comprises a first active component and a second active component, the first active component is nickel and/or cobalt, and the second active component is molybdenum and/or tungsten.

Preferably, the content of the first active component is 1 to 15 wt%, preferably 2 to 8 wt%, calculated as oxide, based on the total amount of the hydro-upgrading catalyst; the content of the second active component is 10 to 40% by weight, preferably 10 to 35% by weight.

Preferably, the catalyst carrier contains silica-alumina, alumina and a Y-type molecular sieve, and the content of the silica-alumina is 1 to 70 weight percent, preferably 5 to 60 weight percent, based on the total weight of the hydrogenation modification catalyst; the content of the Y-type molecular sieve is 1-60 wt%, preferably 15-50 wt%; the content of alumina is 5 to 80% by weight, preferably 5 to 65% by weight.

In the present invention, the first reaction zone and the second reaction zone are connected in series, and can be in the same device or two different devices, and one skilled in the art can select a device commonly used in the art, such as a fixed bed reactor. The temperature of the first reaction zone and the second reaction zone can be controlled by cold hydrogen or cold cycle oil.

In the invention, the hydrodesulfurization depth of the first reaction zone is moderate, the reaction severity of the first reaction zone can be properly reduced, and the reaction is carried out at a high liquid hourly space velocity and a low temperature, so that the service life of the hydrofining catalyst is further prolonged. Preferably, the reaction conditions of the first reaction zone include: the hydrogen partial pressure is 2.0-12.0MPa, preferably 3.2-8.0 MPa; the temperature is 300-450 ℃, preferably 320-420 ℃; the liquid hourly space velocity is 0.3-6h^-1Preferably 2.1 to 4.0h^-1(ii) a Hydrogen-oil ratio of 200-1000Nm³/m³Preferably 300-800Nm³/m³。

In the invention, compared with the reaction conditions of the first reaction zone, the reaction conditions of the second reaction zone are relatively more moderate, the temperature is low, the liquid hourly space velocity is high, and the contact reaction of the second reaction zone can remove residual sulfides and improve the color of diesel oil fraction. Preferably, the reaction conditions of the second reaction zone include: the hydrogen partial pressure is 2.0-12.0MPa, preferably 3.2-8.0 MPa; the temperature is 260-380 ℃, and the preferred temperature is 280-350 ℃; the liquid hourly space velocity is 2-10h^-1Preferably 4-8h^-1(ii) a Hydrogen-oil ratio of 200-1000Nm³/m³Preferably 300-800Nm³/m³。

Preferably, the temperature of the second reaction zone is 10 to 70 ℃ lower than the temperature of the first reaction zone; the liquid-hour volume space velocity of the second reaction zone is 1.5 to 4 hours higher than that of the first reaction zone^-1。

In the present invention, the effluent from the second reaction zone may be subjected to a gas-liquid separation and then the separated liquid phase stream may be subjected to a fractionation. The resulting hydrogen-rich gas may be desulfurized and recycled to the first and second reaction zones. The method of the fractionation may be a method commonly used in the art as long as the desired product can be obtained, and the present invention is not particularly limited thereto.

The present invention will be described in detail below by way of examples.

In the following preparation examples, the composition of the catalyst was calculated from the amounts charged. The mass fractions of sulfur and nitrogen in the product were analyzed using a sulfur-nitrogen analyzer (model number TN/TS3000, available from seimer feishei), and 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).

Preparation example 1

This preparation example is intended to explain the preparation process of the hydrorefining catalyst S1 used in the present invention.

(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 MoO₃And respectively adding the basic cobalt carbonate and the citric acid into the aqueous solution containing the phosphoric acid, and heating and stirring the mixture until the basic cobalt carbonate and the citric acid are completely dissolved to obtain the impregnation solution containing the active metal.

Wherein the mass of the citric acid is 20 weight percent 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. After drying at 200 ℃ for 3h, an oxidized catalyst with a particle size of 1.6mm was obtained, which was designated as hydrofinishing catalyst S1.

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.

After the catalyst is roasted for 3 hours at 400 ℃, the pore size distribution of the catalyst is analyzed by utilizing low-temperature nitrogen adsorption and mercury intrusion method. The specific surface area of the catalyst was 96.0m²(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 86.6% (wherein the ratio of the pore volume of 2 to 4nm to the total pore volume was 9.5%), the ratio of the pore volume of 100-300nm to the total pore volume was 7.2%, the pore volume was 0.26mL/g, and the average pore diameter was 10.8 nm.

Preparation example 2

This preparation example is intended to explain the preparation process of the hydrorefining catalyst S2 used in the present invention.

(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 4h at 700 ℃ 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 15.0 wt.% in the catalyst.

(2) Adding a certain amount of MoO₃Adding the basic nickel carbonate and the acetic acid into a phosphoric acid-containing aqueous solution respectively, and heating and stirring the mixture until the basic nickel carbonate and the acetic acid are completely dissolved to obtain an impregnation solution containing the active metal.

Wherein the mass of the acetic acid is 30 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 catalyst was dried at 200 ℃ for 5h to give an oxidic catalyst with a particle size of 1.6mm, designated as hydrofinishing catalyst S2.

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 46.0 wt%, 20.0 wt% and 20.0 wt%, respectively, based on the dry weight of the catalyst and calculated as an oxide₂O₅The content was 4% by weight, and the content of the inorganic refractory component was 30.0% by weight.

Roasting the catalyst for 3h at 400 ℃, and adsorbing by using low-temperature nitrogenThe pore size distribution is analyzed by mercury intrusion method. The specific surface area of the catalyst was 149m²(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 6.3%), the ratio of the pore volume of 100-300nm to the total pore volume was 10.0%, the pore volume was 0.33mL/g, and the average pore diameter was 8.9 nm.

Preparation example 3

This preparation example is intended to explain the preparation process of the hydrorefining catalyst S3 used in the present invention.

(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 the basic nickel carbonate and the tartaric acid into an aqueous solution containing phosphoric acid respectively, and heating and stirring the mixture until the basic nickel carbonate and the tartaric acid are completely dissolved to obtain an impregnation solution containing active metals.

Wherein the mass of the tartaric acid accounts for 50 wt% of the mass of the inorganic refractory components.

(3) The impregnating solution and the inorganic refractory component are uniformly mixed, and then extruded into strips for forming. The catalyst was dried at 150 ℃ for 8h to give an oxidic catalyst with a particle size of 1.6mm, designated as hydrofinishing catalyst S3.

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.

After the catalyst is roasted for 3 hours at 400 ℃, the pore size distribution of the catalyst is analyzed by utilizing low-temperature nitrogen adsorption and mercury intrusion method. The specific surface area of the catalyst was 151m²The pore size distribution is between 2 and 40nm and 100 and 300nm, wherein the proportion of the pore volume of 2 to 40nm to the total pore volume is 90.0% (wherein, the proportion of the pore volume of 2-4nm to the total pore volume was 7.6%), the proportion of the pore volume of 100-300nm to the total pore volume was 6.1%, the pore volume was 0.28mL/g, and the average pore diameter was 7.4 nm.

Preparation example 4

This preparation example is intended to explain the preparation process of the hydrorefining catalyst S4 used in the present invention.

The procedure of preparation example 1 was followed. In the step (1), a VIII group metal element is not introduced, but the same amount of a VIB group metal element Mo is introduced, and the Mo source is MoO₃And the rest is the same. The hydrorefining catalyst S4 was obtained.

Comparative preparation example 1

This preparation example is intended to explain the conventional process for preparing a hydrorefining catalyst D1.

Commercially available white carbon black (specific surface area: 220 m)²The average pore diameter is 12.7nm), and basic cobalt carbonate powder are uniformly mixed without a roasting step to obtain the inorganic refractory powder containing cobalt. Wherein the amount of basic cobalt carbonate used corresponds to a cobalt (calculated as cobalt oxide) content of the catalyst of 22.0 wt.%. Then, an impregnation solution was prepared in accordance with the procedure (2) of example 1, and a catalyst was prepared in accordance with the procedure (3) of example 1, the composition of the inorganic refractory components and the metal in the dry basis of the catalyst being the same as those of the catalyst of example 1. Thus, a hydrorefining catalyst D1 was obtained.

Comparative preparation example 2

This preparation example is intended to explain the conventional process for preparing a hydrorefining catalyst D2.

The catalyst was extruded from the inorganic refractory precursor, the active component precursor and the organic acid used in preparation example 2, and the content of the inorganic refractory component, the content of the active metal component and the amount of the organic acid in the dry basis of the catalyst were maintained the same as in example 2. Thus, a hydrorefining catalyst D2 was obtained.

Comparative preparation example 3

This preparation example is intended to explain the conventional process for preparing a hydrorefining catalyst D3.

According to the method in preparation example 2, only white carbon black is replaced by pseudo boehmite powder, and the rest is the same. Thus, a hydrorefining catalyst D3 was obtained.

Comparative preparation example 4

This preparation example is intended to explain the conventional process for preparing a hydrorefining catalyst D4.

The same procedure was followed as in preparation example 1 except that no organic acid was added at the time of preparing the active ingredient solution. Thus, a hydrorefining catalyst D4 was obtained.

Comparative preparation example 5

This preparation example is intended to illustrate the production process of conventional hydrorefining catalyst D5.

The procedure of preparation example 1 was followed. In the step (1), the VIII group metal element is not introduced, the VIII group metal element is completely introduced in the step (2), and the rest is the same. Thus, a hydrorefining catalyst D5 was obtained.

In the following examples and comparative examples, the commercial designations of the hydroupgrading catalyst M, the hydroupgrading catalyst N and the hydroupgrading catalyst O are RIC-3, RIC-2 and RHC-1, respectively, and the hydrogenation protecting agents RG-30A and RG-30B are all produced by Changling division, a petrochemical catalyst company, China.

The vulcanization conditions of the catalyst are as follows: the vulcanization pressure is 6.4MPa, and the vulcanized oil contains CS₂2% by weight of kerosene, the volume space velocity being 2h^-1The hydrogen-oil ratio is 300v/v, the temperature is kept for 6h at 230 ℃/h, then the temperature is raised to 320 ℃ for vulcanization for 6h, and the temperature raising rate of each stage is 10 ℃/h.

The catalyst deactivation rate refers to the increase of the reaction temperature of the catalyst per unit time when a certain target product is produced; the average service life of the catalyst means the ratio of the increase in reaction temperature from the initial stage to the final stage of the catalyst operation to the deactivation rate of the catalyst. (the final reaction temperature of the catalyst in the present invention was 420 ℃ C.)

The denitrifying adsorbent A, the denitrifying adsorbent B and the denitrifying adsorbent C are respectively a molecular sieve, activated clay and silica gel.

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 contents of monocyclic aromatic hydrocarbon and aromatic hydrocarbon above double rings in the diesel raw material and the diesel product are analyzed by adopting a near infrared spectrum method.

The properties of the diesel feedstock are shown in table 1.

TABLE 1

Example 1

Straight-run diesel oil as a raw material and hydrogen enter a first reaction zone to sequentially contact and react with a hydrogenation protective agent RG-30A and a hydrofining catalyst S1, wherein the loading volume ratio of the hydrogenation protective agent RG-30A to the hydrofining catalyst S1 is 1: 9, the obtained effluent of the first reaction zone enters a second reaction zone without separation, and is in contact reaction with a hydrogenation modification catalyst M, the obtained effluent of the second reaction zone is subjected to gas-liquid separation, the separated liquid product enters a fractionation system to obtain a diesel product, and the gas rich in hydrogen is circulated back to the two reaction zones. Wherein the liquid phase stream of the effluent of the first reaction zone has a sulfur content of 80 μ g/g and a nitrogen content of 30 μ g/g.

The process conditions and properties of the diesel product are shown in tables 2 and 3, respectively.

The deactivation rate of the hydrorefining catalyst S1 was 1.3 ℃/month, the deactivation rate of the hydrorefining catalyst M was 1.4 ℃/month, and the average service life of the hydrorefining catalyst S1 was 46.1 months.

Example 2

The mixed diesel oil A is taken as a raw material and enters a first reaction zone with hydrogen to sequentially perform contact reaction with a hydrogenation protective agent RG-30B and a hydrofining catalyst S2, and the filling volume ratio of the hydrogenation protective agent RG-30B to the hydrofining catalyst S2 is 1: 9, the obtained effluent of the first reaction zone enters a second reaction zone without separation, and is in contact reaction with a hydrogenation modification catalyst N, the obtained effluent of the second reaction zone is subjected to gas-liquid separation, the separated liquid product enters a fractionation system to obtain a diesel product, and the gas rich in hydrogen is circulated back to the two reaction zones. Wherein the liquid phase stream of the effluent of the first reaction zone has a sulfur content of 60 μ g/g and a nitrogen content of 25 μ g/g.

The deactivation rate of the hydrorefining catalyst S2 was 1.8 ℃/month, the deactivation rate of the hydrorefining catalyst N was 1.2 ℃/month, and the average service life of the hydrorefining catalyst S2 was 30.5 months.

Example 3

The mixed diesel oil A is taken as a raw material, enters a first reaction zone with hydrogen, and sequentially contacts and reacts with a hydrogenation protective agent RG-30A and a hydrofining catalyst S3, and the filling volume ratio of the hydrogenation protective agent RG-30A to the hydrofining catalyst S3 is 1: 9, the obtained effluent of the first reaction zone enters a second reaction zone without separation, and is in contact reaction with a hydrogenation modification catalyst O, the obtained effluent of the second reaction zone is subjected to gas-liquid separation, the separated liquid product enters a fractionation system to obtain a diesel product, and the gas rich in hydrogen is circulated back to the two reaction zones. Wherein the liquid phase stream of the effluent of the first reaction zone has a sulfur content of 60 μ g/g and a nitrogen content of 30 μ g/g.

The deactivation rate of the hydrorefining catalyst S3 was 1.5 ℃/month, the deactivation rate of the hydrorefining catalyst O was 1.5 ℃/month, and the average service life of the hydrorefining catalyst S3 was 46.7 months.

Example 4

The mixed diesel oil B as a raw material and hydrogen enter a first reaction zone to sequentially contact and react with a hydrogenation protective agent RG-30A and a hydrofining catalyst S1, and the filling volume ratio of the hydrogenation protective agent RG-30A to the hydrofining catalyst S1 is 1: 9, the obtained effluent of the first reaction zone enters a second reaction zone without separation, and is in contact reaction with a hydrogenation modification catalyst M, the obtained effluent of the second reaction zone is subjected to gas-liquid separation, the separated liquid product enters a fractionation system to obtain a diesel product, and the gas rich in hydrogen is circulated back to the two reaction zones. Wherein the liquid phase stream of the effluent of the first reaction zone has a sulfur content of 40 μ g/g and a nitrogen content of 15 μ g/g.

The process conditions and the properties of the main product are shown in tables 2 and 3, respectively.

The deactivation rate of the hydrorefining catalyst S1 was 1.5 ℃/month, the deactivation rate of the hydrorefining catalyst M was 0.7 ℃/month, and the average service life of the hydrorefining catalyst S1 was 33.3 months.

Example 5

The mixed diesel oil B as a raw material and hydrogen enter a first reaction zone to sequentially contact and react with a hydrogenation protective agent RG-30A and a hydrofining catalyst S3, and the filling volume ratio of the hydrogenation protective agent RG-30A to the hydrofining catalyst S3 is 1: 9, the obtained effluent of the first reaction zone enters a second reaction zone without separation, and is in contact reaction with a hydrogenation modification catalyst M, the obtained effluent of the second reaction zone is subjected to gas-liquid separation, the separated liquid product enters a fractionation system to obtain a diesel product, and the gas rich in hydrogen is circulated back to the two reaction zones. Wherein the liquid phase stream of the effluent of the first reaction zone has a sulfur content of 50 μ g/g and a nitrogen content of 20 μ g/g.

The deactivation rate of the hydrorefining catalyst S3 was 1.8 ℃/month, the deactivation rate of the hydrorefining catalyst M was 1.3 ℃/month, and the average service life of the hydrorefining catalyst S3 was 30.6 months.

Example 6

The procedure is as in example 4, except that the hydrofinishing catalyst S1 is added instead of hydrofinishing catalyst S4. Wherein the liquid phase stream of the effluent from the first reaction zone has a sulfur content of 110 μ g/g and a nitrogen content of 30 μ g/g.

The properties of the diesel product are shown in Table 3.

The deactivation rate of the hydrorefining catalyst S4 was 2.05 ℃/month, the deactivation rate of the hydrorefining catalyst M was 2.0 ℃/month, and the average service life of the hydrorefining catalyst S4 was 24.4 months.

Comparative example 1

Taking straight-run diesel oil as a raw material, allowing the straight-run diesel oil and hydrogen to enter a first reaction zone, sequentially carrying out contact reaction with a hydrogenation protective agent RG-30A and a hydrofining catalyst D1, wherein the loading volume ratio of the hydrogenation protective agent RG-30A to the hydrofining catalyst D1 is 1: 9, the obtained effluent of the first reaction zone enters a second reaction zone without separation, and is in contact reaction with a hydrogenation modification catalyst M, the obtained effluent of the second reaction zone is subjected to gas-liquid separation, the separated liquid product enters a fractionation system to obtain a diesel product, and the gas rich in hydrogen is circulated back to the two reaction zones. Wherein the liquid phase stream of the effluent of the first reaction zone has a sulfur content of 70 μ g/g and a nitrogen content of 50 μ g/g.

The process conditions and properties of the diesel product are shown in tables 2 and 4, respectively.

The deactivation rate of the hydrorefining catalyst D1 was 3.0 ℃/month, the deactivation rate of the hydrorefining catalyst M was 2.0 ℃/month, and the average service life of the hydrorefining catalyst D1 was 16.7 months.

Comparative example 2

And (2) allowing the mixed diesel oil A and hydrogen to enter a first reaction zone, and sequentially performing contact reaction with a hydrogenation protective agent RG-30A and a hydrofining catalyst D2, wherein the filling volume ratio of the hydrogenation protective agent RG-30A to the hydrofining catalyst D2 is 1: 9, the obtained effluent of the first reaction zone enters a second reaction zone without separation, and is in contact reaction with a hydrogenation modification catalyst M, the obtained effluent of the second reaction zone is subjected to gas-liquid separation, the separated liquid product enters a fractionation system to obtain a diesel product, and the gas rich in hydrogen is circulated back to the two reaction zones. Wherein the liquid phase stream of the effluent of the first reaction zone has a sulfur content of 50 μ g/g and a nitrogen content of 35 μ g/g.

The deactivation rate of the hydrorefining catalyst D2 was 3.5 ℃/month, the deactivation rate of the hydrorefining catalyst M was 1.8 ℃/month, and the average service life of the hydrorefining catalyst D2 was 11.4 months.

Comparative example 3

The procedure of example 1 was repeated, except that the hydrofinishing catalyst S1 was replaced with hydrofinishing catalyst D3. Wherein the liquid phase stream of the effluent from the first reaction zone has a sulphur content of 100 μ g/g and a nitrogen content of 50 μ g/g.

The properties of the diesel product are shown in Table 4.

The deactivation rate of the hydrorefining catalyst D3 was 2.8 ℃/month, the deactivation rate of the hydrorefining catalyst M was 1.5 ℃/month, and the average service life of the hydrorefining catalyst D3 was 21.4 months.

Comparative example 4

The procedure of example 1 was repeated, except that the hydrofinishing catalyst S1 was replaced with hydrofinishing catalyst D4. Wherein the liquid phase stream of the effluent from the first reaction zone has a sulfur content of 120 μ g/g and a nitrogen content of 60 μ g/g.

The properties of the diesel product are shown in Table 4.

The deactivation rate of the hydrorefining catalyst D4 was 3.1 ℃/month, the deactivation rate of the hydrorefining catalyst M was 1.6 ℃/month, and the average service life of the hydrorefining catalyst D4 was 19.4 months.

Comparative example 5

The procedure of example 1 was repeated, except that the hydrofinishing catalyst S1 was replaced with hydrofinishing catalyst D5. Wherein the liquid phase stream of the effluent of the first reaction zone has a sulfur content of 150 μ g/g and a nitrogen content of 70 μ g/g.

The properties of the diesel product are shown in Table 4.

The deactivation rate of the hydrorefining catalyst D5 was 3.2 ℃/month, the deactivation rate of the hydrorefining catalyst M was 1.7 ℃/month, and the average service life of the hydrorefining catalyst D5 was 18.7 months.

TABLE 2

TABLE 3

TABLE 4

Diesel oil product	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5
						Density, g/cm³	0.8294	0.8430	0.8321	0.8325	0.8335
Color intensity	0.5	0.8	0.5	0.5	0.5
						Sulfur content, μ g/g	10	25	15	18	20
Nitrogen content,. mu.g/g	1.0	2.0	1	1.5	2
						Total aromatic hydrocarbons, m%	18.0	29.0	18.7	19.7	20.5
Monocyclic aromatic hydrocarbon, m%	15.5	20.0	16	16.8	17.5
						Aromatic hydrocarbons over bicyclo ring, m%	2.5	9.0	2.7	2.9	3
Desulfurization rate%	99.90	99.74	99.85	99.82	99.8
						Denitrification rate%	98.48	99.26	99.48	97.73	96.97
Total aromatics removal rate%	40.59	24.28	38.28	34.98	32.34
						Distillation range (ASTM D-86), deg.C	178～339	192～360	175～340	179～342	175～343

From the results, the method provided by the invention can be used for producing the ultra-low sulfur diesel with polycyclic aromatic hydrocarbon (aromatic hydrocarbon above double rings) less than 7% and sulfur content less than l0 mug/g, and can reduce the severity of operating conditions, reduce the reaction temperature, increase the liquid time volume airspeed, prolong the service life of the catalyst, further effectively prolong the whole operating period of the device and realize long-period operation.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A method of producing clean diesel, the method comprising: carrying out contact reaction on a diesel raw material and hydrogen with a hydrofining catalyst in a first reaction zone to obtain an effluent of the first reaction zone; wherein the hydrofining catalyst contains an inorganic refractory component, a hydrodesulfurization catalytic active component and carboxylic acid; the inorganic refractory component contains at least one of silicon oxide, magnesium oxide, calcium oxide, zirconium oxide and titanium oxide and part of hydrodesulfurization catalytic active component;

2. The process of claim 1 wherein the first reaction zone effluent comprises a vapor phase stream and a liquid phase stream, the liquid phase stream having a sulfur content of from 20 to 200 μ g/g and a nitrogen content of from 0 to 50 μ g/g.

3. A method according to claim 2, wherein the liquid phase stream has a sulphur content of 40-100 μ g/g and a nitrogen content of 10-30 μ g/g.

4. The process according to any one of claims 1 to 3, wherein the hydrodesulphurization catalytically active component comprises a group VIII metal element and a group VIB metal element;

wherein, in the hydrofining catalyst, 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 VIB group metal element is 35-75 wt%;

and/or 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.

5. The process according to claim 4, wherein the group VIII metal element is contained in the hydrorefining catalyst in an amount of 20 to 30% by weight in terms of oxide based on the dry weight of the catalyst; the content of the VIB group metal element is 40-65 wt%.

6. The process of any one of claims 1 to 3, wherein the portion of the hydrodesulfurization catalytically active component is a portion of the group VIII metal elements, the portion of the group VIII metal elements being present in an amount of from 60 to 90 wt.% of the total group VIII metal element content.

7. The process as claimed in any one of claims 1 to 3, wherein the pore volume at a pore diameter of 2 to 40nm is 75 to 90% of the total pore volume and the pore volume at a pore diameter of 100 and 300nm is 5 to 15% of the total pore volume;

and/or, the hydrofining catalyst is a shaped catalyst;

and/or the shape of the hydrofining catalyst is cylindrical, clover-shaped or honeycombed;

and/or the specific surface area of the hydrofining catalyst is 70-200m²Per gram, pore volume of 0.15-0.6mL/g, average pore diameter of 5-25 nm;

and/or, in the hydrofinishing catalyst, the pore volume of 2-4nm is not more than 10% of the total pore volume.

8. A process according to any one of claims 1 to 3, wherein the inorganic refractory component is present in an amount of from 5 to 40 wt%, based on the dry weight of the catalyst;

and/or the weight ratio of the carboxylic acid to the inorganic refractory component on a dry basis is from 0.1 to 0.8: 1;

and/or 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.

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

and/or the weight ratio of the carboxylic acid to the inorganic refractory component on a dry basis is from 0.2 to 0.6: 1.

10. the process of any of claims 1-3, wherein the hydrofinishing catalyst further comprises phosphorus, based on the dry weight of the catalyst and P₂O₅The content of the phosphorus element is 0.8-10 wt%.

11. The process of claim 10 wherein P is the weight of the catalyst on a dry basis₂O₅The content of the phosphorus element is 1-8 wt%.

12. The method of any one of claims 1-3, 5, 9, and 11, wherein the hydrofinishing catalyst is prepared by a method comprising:

13. The method of claim 4, wherein the hydrofinishing catalyst is prepared by a process comprising:

14. The method of claim 6, wherein the hydrofinishing catalyst is prepared by a process comprising:

15. The method of claim 7, wherein the hydrofinishing catalyst is prepared by a process comprising:

16. The method of claim 8, wherein the hydrofinishing catalyst is prepared by a process comprising:

17. The method of claim 10, wherein the hydrofinishing catalyst is prepared by a process comprising:

18. The method according to claim 12, wherein the impregnation liquid obtained in step (2) further contains a phosphorus-containing substance;

and/or the phosphorus-containing substance is at least one selected from phosphoric acid, hypophosphorous acid, ammonium phosphate and ammonium dihydrogen phosphate.

19. The method according to any one of claims 13 to 17, wherein the impregnation liquid obtained in step (2) further contains a phosphorus-containing substance;

20. The method of claim 12, wherein in step (1), the roasting conditions comprise: the roasting temperature is 300-900 ℃; the roasting time is 1-15 h.

21. The method of claim 20, wherein in step (1), the roasting conditions comprise: the roasting temperature is 400-800 ℃; the roasting time is 3-8 h.

22. The method of any one of claims 13-17, wherein in step (1), the firing conditions comprise: the roasting temperature is 300-900 ℃; the roasting time is 1-15 h.

23. The method of claim 22, wherein in step (1), the roasting conditions comprise: the roasting temperature is 400-800 ℃; the roasting time is 3-8 h.

24. The method of claim 12, wherein in step (3), the drying conditions comprise: the drying temperature is 50-250 ℃; the drying time is 2-10 h.

25. The method of claim 24, wherein in step (3), the drying conditions comprise: the drying temperature is 100-200 ℃; the drying time is 3-8 h.

26. The method according to any one of claims 13 to 17, wherein in step (3), the drying conditions comprise: the drying temperature is 50-250 ℃; the drying time is 2-10 h.

27. The method of claim 26, wherein in step (3), the drying conditions comprise: the drying temperature is 100-200 ℃; the drying time is 3-8 h.

28. The method of claim 12, wherein the silica precursor is at least one of silica sol, silica white, and silica dioxide; the magnesium oxide precursor is at least one of magnesium hydroxide, magnesium nitrate, magnesium carbonate, magnesium acetate and magnesium oxide; the precursor of the calcium oxide is at least one of calcium hydroxide, calcium carbonate, calcium oxalate, calcium nitrate, calcium acetate and calcium oxide; the zirconia precursor is at least one of zirconium hydroxide, zirconium carbonate, zirconium nitrate, zirconium acetate and zirconia; the precursor of the titanium oxide is at least one of titanium hydroxide, titanium nitrate and titanium acetate;

and/or 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.

29. The method of any one of claims 13-17, wherein the silica precursor is at least one of silica sol, silica and silica; the magnesium oxide precursor is at least one of magnesium hydroxide, magnesium nitrate, magnesium carbonate, magnesium acetate and magnesium oxide; the precursor of the calcium oxide is at least one of calcium hydroxide, calcium carbonate, calcium oxalate, calcium nitrate, calcium acetate and calcium oxide; the zirconia precursor is at least one of zirconium hydroxide, zirconium carbonate, zirconium nitrate, zirconium acetate and zirconia; the precursor of the titanium oxide is at least one of titanium hydroxide, titanium nitrate and titanium acetate;

30. The method of any one of claims 1-3, wherein the hydro-upgrading catalyst comprises a catalyst support and a hydrogenation active component supported on the catalyst support, the hydrogenation active component comprising a first active component and a second active component, the first active component being nickel and/or cobalt, the second active component being molybdenum and/or tungsten;

and/or, the content of the first active component is 1-15 wt% calculated by oxide based on the total amount of the hydro-upgrading catalyst; the content of the second active component is 10-40 wt%;

and/or the catalyst carrier contains silica-alumina, alumina and a Y-type molecular sieve, and the content of the silica-alumina is 1-70 wt% based on the total amount of the hydrogenation modification catalyst; the content of the Y-type molecular sieve is 1-60 wt%; the content of alumina is 5-80 wt%.

31. The process according to claim 30, wherein the first active component is present in an amount of 2 to 8 wt.% on an oxide basis, based on the total amount of the hydro-upgrading catalyst; the content of the second active component is 10-35 wt%;

and/or the catalyst carrier contains silica-alumina, alumina and a Y-type molecular sieve, and the content of the silica-alumina is 5-60 wt% based on the total amount of the hydrogenation modification catalyst; the content of the Y-type molecular sieve is 15-50 wt%; the content of alumina is 5-65 wt%.

32. The process of any one of claims 1-3, wherein the reaction conditions of the first reaction zone comprise: the hydrogen partial pressure is 2.0-12.0 MPa; the temperature is 300-450 ℃; the liquid hourly space velocity is 0.3-6h^-1(ii) a Hydrogen-oil ratio of 200-1000Nm³/m³；

And/or the reaction conditions of the second reaction zone comprise: the hydrogen partial pressure is 2.0-12.0 MPa; the temperature is 260 ℃ and 380 ℃; the liquid hourly space velocity is 2-10h^-1(ii) a Hydrogen-oil ratio of 200-1000Nm³/m³。

33. The process of claim 32, wherein the reaction conditions of the first reaction zone comprise: the hydrogen partial pressure is 3.2-8.0 MPa; the temperature is 320-420 ℃; the liquid hourly space velocity is 2.1-4.0h^-1(ii) a The hydrogen-oil ratio is 300-800Nm³/m³；

And/or the reaction conditions of the second reaction zone comprise: the hydrogen partial pressure is 3.2-8.0 MPa; the temperature is 280-350 ℃; the liquid hourly space velocity is 4-8h^-1(ii) a HydrogenOil ratio of 300-800Nm³/m³。