CN111100707B

CN111100707B - Hydrocracking method for producing chemical material and fuel oil

Info

Publication number: CN111100707B
Application number: CN201811268991.6A
Authority: CN
Inventors: 赵阳; 章然; 赵广乐; 毛以朝
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: 2018-10-29
Filing date: 2018-10-29
Publication date: 2022-04-08
Anticipated expiration: 2038-10-29
Also published as: CN111100707A

Abstract

A hydrocracking process for producing chemical and fuel oils comprising: in the presence of hydrogen, raw oil sequentially passes through a first hydrogenation reaction zone, a second hydrogenation reaction zone and a third hydrogenation reaction zone for reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation to obtain naphtha fraction, aviation kerosene fraction, diesel fraction and tail oil fraction. The method provided by the invention has the advantages of high device operation efficiency, long period and high aviation coal selectivity in the product.

Description

Hydrocracking method for producing chemical material and fuel oil

Technical Field

The present invention relates to a method for cracking hydrocarbon oil in the presence of hydrogen, and more particularly to a hydrocracking method for producing an improved industrial material and fuel oil.

Background

Ethylene is a basic raw material of petrochemical industry, and with the development of national economy, the ethylene production capacity of China is rapidly increased, but the ethylene production capacity cannot meet the demand of domestic markets for ethylene, and about half of ethylene production capacity depends on import. Therefore, the development of petrochemical feedstock olefin production technologies is one direction of development in the petrochemical industry. Steam cracking of hydrocarbons is the primary means of ethylene production. In the process of preparing ethylene by steam cracking, the raw oil cost accounts for a large proportion of the total cost, and generally the raw oil cost accounts for more than 60 percent of the total cost. Therefore, the optimal selection of raw oil is an important factor influencing the benefit of the ethylene plant. From the world, the sources of raw materials for preparing ethylene by steam cracking are wide, light fraction raw materials comprise light hydrocarbon and naphtha, and heavy fraction raw materials comprise AGO, hydrocracking tail oil and the like. Among them, light hydrocarbons and hydrocracking tail oil are ethylene raw materials with better economical efficiency, followed by naphtha, and AGO is a relatively poor raw material. The light hydrocarbon yield in China is not high, and the proportion of light hydrocarbon in ethylene raw materials in China is very small. In addition, the crude oil in China is mostly heavy crude oil, the extraction rate of straight-run naphtha is low, the straight-run naphtha is also used as a raw material for producing high-octane reformate, and the contradiction between raw materials in oil refining and chemical industry is increasingly prominent. Thus, the production of ethylene feeds by a hydrocracking unit is an advantageous way to expand the source of the ethylene feedstock.

The hydrocracking technology is characterized in that heavy fractions such as Vacuum Gas Oil (VGO) and the like react with hydrogen in the presence of a catalyst, so that the dual purposes of improving the product quality and lightening the heavy oil product are achieved. Hydrocracking yields a wide cut product from the gas, naphtha, middle distillate and unconverted tail oil fraction. The hydrocracking tail oil has high paraffin and naphthene content and low aromatic hydrocarbon content, and is a high-quality ethylene raw material prepared by steam cracking.

The reformer is an important secondary processing unit in a refinery for producing high octane gasoline blending components or for producing aromatic base stocks. The reformed gasoline has the characteristics of high octane number, no olefin, no sulfur and nitrogen impurities and the like, and is a high-quality gasoline blending component. Benzene, toluene and xylene are basic raw materials in petrochemical industry, and the oil generated by the reforming device is rich in benzene, toluene and xylene, and high-value aromatic hydrocarbon products can be obtained through separation. Straight run naphtha is the primary source of reformer feed. For a long time, the yield of crude oil light oil is low in China, the straight-run naphtha is one of the raw materials of an ethylene unit, and the shortage of reforming raw materials becomes one of the main factors limiting the development of the reforming unit.

The hydrocracking process is an important means for heavy oil conversion, and the obtained heavy naphtha has the characteristics of high aromatic hydrocarbon content and low sulfur and nitrogen impurity content, can be directly used as a high-quality reforming device for feeding, and makes up for the defects of the straight-run naphtha.

Generally, refineries refer to light and heavy naphthas and tails collectively as chemical feedstocks because light naphthas and tails are premium ethylene cracking feedstocks due to high paraffin content, while heavy naphthas are premium reformer feeds due to high aromatic potential.

CN101117596B discloses a hydrogenation method capable of flexibly producing diesel oil and chemical raw materials. Three reactors are set up, namely a hydrotreating 1 reactor, a hydrocracking reactor and a hydrotreating 2 reactor. Wherein, the tail oil is recycled for producing diesel oil in a high yield, and the diesel oil is recycled for producing naphtha in a high yield.

CN101173189B discloses a two-stage hydrocracking method for producing chemical raw materials. Characterized in that heavy raw oil is mixed with hydrogen and then enters a first-stage hydrotreating zone, hydrogen-rich gas obtained by separating first-stage effluent directly enters a second-stage hydrocracking reaction zone, and naphtha and tail oil obtained by separation are used as chemical raw materials. The middle distillate oil enters a second-stage hydrogenation treatment area to be cracked independently or in a mixture with other separation distillate oil.

CN103627431A discloses a hydrocracking process for producing middle distillate and a tail oil rich in paraffins. And mixing the raw oil with hydrogen, and then reacting with a hydrofining catalyst and a hydrocracking catalyst in sequence to obtain naphtha, kerosene, diesel oil and tail oil fraction, wherein the tail oil fraction is completely extracted or partially recycled to an outlet of a refining reactor.

Disclosure of Invention

In order to overcome the problem that high-quality chemical raw materials cannot be produced simultaneously when the aviation kerosene and diesel oil are produced in a high-yield manner and diesel oil are produced properly in the prior art, the invention provides a hydrocracking method for producing chemical materials and fuel oil, which realizes the high-efficiency production of aviation kerosene and simultaneously gives consideration to the high-yield chemical materials.

The hydrocracking method for producing chemical materials and fuel oil provided by the invention comprises the following steps: in the presence of hydrogen, raw oil sequentially passes through a first hydrogenation reaction zone, a second hydrogenation reaction zone and a third hydrogenation reaction zone for reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation to obtain naphtha fraction, aviation kerosene fraction, diesel fraction and tail oil fraction; a first hydrogenation reaction zone is filled with a hydrofining catalyst I, a second hydrogenation reaction zone is filled with a hydrocracking catalyst, and a third hydrogenation reaction zone is filled with a hydrofining catalyst II;

the hydrocracking catalyst comprises 45-90 wt% of a carrier, 1-40 wt% of a first metal component and 1-15 wt% of a second metal component, wherein the carrier is calculated by the weight of the hydrocracking catalyst on a dry basis, and the first metal component is calculated by the weight of a metal oxide; the carrier comprises a phosphorus-containing Y-type molecular sieve and a heat-resistant inorganic oxide, wherein the weight ratio of the phosphorus-containing Y-type molecular sieve to the heat-resistant inorganic oxide is (0.03-20): 1; the first metal component is a metal selected from group VIB; the second metal component is a metal selected from group VIII. Preferably, the phosphorus content of the phosphorus-containing Y-type molecular sieve is 0.3-5 wt% calculated by oxide, the pore volume is 0.2-0.95 mL/g, and the ratio of pyridine infrared B acid to L acid is 2-10.

The method provided by the invention can greatly increase the yield of the aviation kerosene in the product, and simultaneously can produce high-quality chemical materials and less diesel oil. In addition, the selectivity of the aviation kerosene and naphtha is higher, and the influence on the quality of tail oil is small. Compared with the prior art, the optimized hydrocracking catalyst has high activity and good stability, so that the hydrocracking device has high space velocity and high efficiency and can run for a long period.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The hydrocracking method for producing chemical materials and fuel oil provided by the invention comprises the following steps: in the presence of hydrogen, raw oil sequentially passes through a first hydrogenation reaction zone, a second hydrogenation reaction zone and a third hydrogenation reaction zone for reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation to obtain naphtha fraction, aviation kerosene fraction, diesel fraction and tail oil fraction;

a first hydrogenation reaction zone is filled with a hydrofining catalyst I, a second hydrogenation reaction zone is filled with a hydrocracking catalyst, and a third hydrogenation reaction zone is filled with a hydrofining catalyst II;

Optionally, the raw oil is at least one selected from the group consisting of straight run gas oil, vacuum gas oil, demetallized oil, atmospheric residue, deasphalted vacuum residue, coker distillate, catalytically cracked distillate, shale oil, tar sand oil, and coal liquefied oil.

Preferably, the reaction conditions of the first hydrogenation reaction zone are: the hydrogen partial pressure is 6.0MPa to 20.0MPa, the reaction temperature is 280 ℃ to 400 ℃, and the liquid hourly space velocity is 0.5h^-1～6h^-1The volume ratio of hydrogen to oil is 300-2000; it is further preferred that the reaction conditions in the first hydrogenation reaction zone are: the hydrogen partial pressure is 7.0MPa to 15.0MPa, the reaction temperature is 290 ℃ to 390 ℃, and the liquid hourly space velocity is 0.8h^-1～5h^-1The volume ratio of hydrogen to oil is 300-1800;

the reaction conditions of the second hydrogenation reaction zone are as follows: the hydrogen partial pressure is 6.0MPa to 20.0MPa, the reaction temperature is 290 ℃ to 420 ℃, and the liquid hourly space velocity is 0.3h^-1～5h^-1The volume ratio of hydrogen to oil is 300-2000; it is further preferred that the reaction conditions in the second hydrogenation reaction zone are: the hydrogen partial pressure is 7.0MPa to 15.0MPa, the reaction temperature is 300 ℃ to 410 ℃, and the liquid hourly space velocity is 0.3h^-1～4h^-1The volume ratio of hydrogen to oil is 300-1800;

the reaction conditions of the third hydrogenation reaction zone are as follows: the hydrogen partial pressure is 6.0MPa to 20.0MPa, the reaction temperature is 280 ℃ to 400 ℃, and the liquid hourly space velocity is 1h^-1～8h^-1The volume ratio of hydrogen to oil is 300-2000; the reaction conditions of the third hydrogenation reaction zone are preferably as follows: the hydrogen partial pressure is 7.0MPa to 15.0MPa, the reaction temperature is 280 ℃ to 400 ℃, and the liquid hourly space velocity is 1.5h^-1～7h^-1The volume ratio of hydrogen to oil is 300-1800.

In the preferred situation, the reaction product is subjected to gas-liquid separation through a high-pressure separator, the obtained liquid phase material flow enters a low-pressure separator for further gas-liquid separation, and then the obtained liquid phase material flow enters a fractionation system for fractionation to obtain gas, naphtha fraction (the distillation range is that the final distillation point is less than 150 ℃), aviation kerosene fraction (the distillation range is 150-270 ℃), diesel fraction (the distillation range is 270-330 ℃) and tail oil fraction (the distillation range is that the initial distillation point is more than 330 ℃).

In a preferred aspect of the present invention, at least 50 weight percent of the tail oil fraction, based on the total tail oil fraction, is recycled back to the third hydrogenation reaction zone.

In the invention, the selectivity of the aviation kerosene is calculated by the mass fraction of the fraction at 150-270 ℃ in the liquid product in the fraction at <270 ℃.

Definition of the conversion of the fractions >330 ℃ in the present invention: based on 100% of the feed, (mass fraction of the feed >330 ℃ fraction-yield of the product >330 ℃ fraction)/mass fraction of the feed >330 ℃ fraction x 100%.

The hydrorefining catalyst I and the hydrorefining catalyst II according to the present invention are not particularly limited, and any catalyst satisfying the hydrorefining function may be used, for example, a commercially available hydrorefining catalyst or a laboratory hydrorefining catalyst. Preferably, the hydrofinishing catalyst I and hydrofinishing catalyst II are at least one catalyst selected from group VIB non-noble metals, or at least one selected from group VIII non-noble metals, or a combination thereof, supported on amorphous alumina or/and silica.

Further preferably, the group VIII non-noble metal is selected from nickel and/or cobalt, the group VIB non-noble metal is selected from molybdenum and/or tungsten, based on the total weight of the hydrofining catalyst I or hydrofining catalyst II, the total content of the nickel and/or cobalt calculated by oxides is 1 wt% to 15 wt%, the total content of the molybdenum and/or tungsten calculated by oxides is 5 wt% to 40 wt%, and the balance is a carrier.

In the hydrocracking catalyst adopted by the invention, the phosphorus-containing Y-type molecular sieve as a carrier component has special performance, so that the hydrocracking catalyst has higher hydrocracking activity and ring opening selectivity, the naphthenic rings of tetrahydronaphthalene, tetrahydrophenanthrene and decahydrophenanthrene can be opened, and monocyclic naphthenic hydrocarbon is reserved, thereby reducing the density and improving the hydrogen content. Preferably, the phosphorus content of the phosphorus-containing Y-type molecular sieve is 0.3-5 wt% calculated by oxide, the pore volume is 0.2-0.95 mL/g, and the ratio of pyridine infrared B acid to L acid is 2-10.

The phosphorus-containing Y-type molecular sieve has a higher ratio of the B acid content to the L acid content. Particularly, the phosphorus-containing Y-type molecular sieve not only reserves high ratio of framework aluminum to non-framework aluminum, but also reserves certain non-framework aluminum at a position of-4 to-6 ppm or at a position of 3 to 7ppm at the position of the non-framework aluminum. Specifically, in an Al27-NMR structural spectrum of the molecular sieve, the peak height ratio of framework aluminum to non-framework aluminum of 60 +/-1 ppm and-1 +/-1 ppm, namely I60ppm/I-1ppm, can be 5-40; and the chemical shift position of 0ppm of non-framework aluminum has two obvious characteristic peaks: -1 + -1ppm, and-5.5 + -2 ppm or 3-7 ppm, the ratio of the peak heights of the two, i.e., I-1ppm/I + -6ppm, may be 0.4-2, preferably 0.8-2, wherein I + -6ppm is the greater of the peak heights of-5.5 + -2 ppm and 3-7 ppm.

Preferably, the phosphorus-containing Y-type molecular sieve is prepared by performing special hydrothermal treatment and acid washing treatment on a phosphorus-containing molecular sieve raw material. Specifically, the preparation step of the phosphorus-containing Y-type molecular sieve may include:

a. carrying out hydro-thermal treatment on a phosphorus-containing molecular sieve raw material for 0.5-10h at the temperature of 350-700 ℃ and the pressure of 0.1-2MPa in the presence of water vapor to obtain a hydro-thermally treated molecular sieve material; calculated by oxide and based on the dry weight of the phosphorus-containing molecular sieve raw material, the phosphorus content of the phosphorus-containing molecular sieve raw material is 0.1-15 wt%, and the sodium content is 0.5-4.5 wt%;

b. b, adding water into the molecular sieve material subjected to the hydrothermal treatment obtained in the step a for pulping to obtain molecular sieve slurry, heating the molecular sieve slurry to 40-95 ℃, keeping the temperature, and continuously adding an acid solution into the molecular sieve slurry, wherein the ratio of the weight of acid in the acid solution to the dry weight of the phosphorus-containing molecular sieve raw material is (0.01-0.6): 1, taking 1L of the molecular sieve slurry as a reference, taking H + as the reference, adding the acid solution at a speed of 0.05-10 mol/H, reacting at constant temperature for 0.5-20H after the acid is added, and collecting a solid product.

In the step a, the phosphorus-containing molecular sieve raw material refers to a phosphorus-containing molecular sieve. By adopting the phosphorus-containing molecular sieve as a raw material, the phosphorus-aluminum species outside the molecular sieve framework can improve the framework stability of the molecular sieve, thereby further improving the performance of the molecular sieve. The structure of the phosphorus-containing molecular sieve raw material can be an octahedral zeolite molecular sieve structure, preferably a phosphorus-containing Y-type molecular sieve, the unit cell constant of the phosphorus-containing molecular sieve raw material can be 2.425-2.47 nm, and the specific surface area of the phosphorus-containing molecular sieve raw material can be 250-750 m²The pore volume may be 0.2 to 0.95 ml/g.

In the step a, the water content of the phosphorus-containing molecular sieve raw material is preferably 10-40 wt%. The phosphorus-containing molecular sieve raw material with the water content can be obtained by adding water into the molecular sieve, pulping, filtering and drying. The phosphorus-containing molecular sieve raw material is preferably granular, and the content of the phosphorus-containing molecular sieve raw material with the granularity range of 1 mm-500 mm can be 10-100 wt%, preferably 30-100 wt% of the total weight of the phosphorus-containing molecular sieve raw material. Further, the content of the phosphorus-containing molecular sieve raw material with the granularity range of 5 mm-100 mm is 30-100 wt% of the total weight of the phosphorus-containing molecular sieve raw material. Wherein the particle size is in terms of the diameter of the circumscribed circle of particles. The adoption of the phosphorus-containing molecular sieve raw material with the granularity range for hydrothermal treatment can obviously improve the mass transfer effect of the hydrothermal treatment, reduce the material loss and improve the stability of operation. The particle size control method of the molecular sieve raw material can be conventional in the field, such as a sieving method, an extrusion strip method, a rolling ball method and the like.

Wherein, the meaning of the water adding and pulping in the step b is well known to those skilled in the art, and the ratio of the weight of the water in the molecular sieve slurry obtained after pulping to the dry weight of the phosphorus-containing molecular sieve raw material can be (14-5): 1.

in the step b, the molecular sieve slurry is preferably heated to 50-85 ℃, and then the acid solution is continuously added into the molecular sieve slurry while maintaining the temperature until the weight of the acid in the acid solution reaches a set amount. The most important of the preparation steps of the phosphorus-containing Y-type molecular sieve is that a continuous acid adding mode is adopted, acid adding and acid washing reaction are carried out simultaneously, the acid adding speed is low, the dealumination process is more moderate, and the improvement of the performance of the molecular sieve is facilitated.

Wherein, the acid solution can be continuously added into the molecular sieve slurry at one time, namely, the whole acid solution is continuously added according to a specific acid adding speed, and then the reaction is carried out at constant temperature. In particular, the acid solution may also be added in multiple portions in order to increase the utilization of the material and reduce the waste output. For example, the acid solution can be added to the molecular sieve slurry at a specific acid addition rate of 2-10 times, and after each acid addition, the reaction can be carried out at constant temperature for a period of time to continue the next acid addition until the set amount of the acid solution is added. When the acid solution is added in multiple portions, the ratio of the weight of acid in the acid solution to the dry weight of the phosphorus-containing molecular sieve starting material is preferably (0.01-0.3): 1. the acid concentration of the acid solution can be 0.01-15.0 mol/L, and the pH value can be 0.01-3. The acid may be a conventional inorganic acid and/or organic or acid, and for example, may be at least one selected from phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, citric acid, tartaric acid, formic acid and acetic acid.

Wherein, the preparation step of the phosphorus-containing Y-type molecular sieve can also comprise the following steps: in step b, adding an ammonium salt into the molecular sieve slurry during the adding of the acid solution, wherein the ammonium salt can be at least one selected from ammonium nitrate, ammonium chloride and ammonium sulfate, and the weight ratio of the ammonium salt to the dry weight of the phosphorus-containing molecular sieve raw material can be (0.1-2.0): 1. the ammonium salt may be added to the molecular sieve slurry independently of the acid solution, or an aqueous solution containing the ammonium salt and the acid may be prepared in a desired amount and added to the molecular sieve slurry.

Wherein, the preparation step of the phosphorus-containing Y-type molecular sieve can also comprise the following steps: and collecting the solid product, and then washing and drying to obtain the phosphorus-containing Y-type molecular sieve. The washing and drying are conventional steps for preparing the molecular sieve, and the disclosure is not particularly limited. For example, the drying may be performed by using an oven, a mesh belt, a converter, or the like, and the drying conditions may be: the temperature is 50-350 ℃, and preferably 70-200 ℃; the time is 1-24 h, preferably 2-6 h.

According to the invention, the heat-resistant inorganic oxide can improve the strength of the catalyst, and improve and adjust the physicochemical properties of the catalyst, such as improving the pore structure of the catalyst. The heat-resistant inorganic oxide may be an inorganic oxide commonly used for hydrogenation catalyst supports, such as alumina, silica, amorphous silica-alumina compounds, zirconia, magnesia, thoria, beryllia, boria, cadmium oxide, and the like. In a preferred embodiment of the present disclosure, the heat-resistant inorganic oxide is preferably alumina, which may include gibbsite such as gibbsite (gibbsite), bayerite nordstrandite (bayerite) and diaspore such as boehmite (boehmite, diasporite, pseudoboehmite). In other embodiments, the refractory inorganic oxide is of another species or combination.

Preferably, the first metal component is molybdenum and/or tungsten; the second metal component is at least one selected from iron, nickel and cobalt.

The hydrocracking catalyst can be prepared by a conventional method, for example, the preparation method of the hydrocracking catalyst can comprise the following steps: the impregnation liquid containing the metal precursor is contacted with the carrier for impregnation, and then the material obtained after the impregnation is dried.

The preparation method of the carrier is well known to those skilled in the art, and may include, for example: mixing the phosphorus-containing Y-type molecular sieve, the heat-resistant inorganic oxide, the solvent and the optional auxiliary agent, and then molding and drying to obtain the carrier. The molding method can adopt various conventional methods, such as tabletting molding, rolling ball molding or extrusion molding. The solvent is a common solvent in the catalyst forming process. When the extrusion molding method is employed, an appropriate amount of an auxiliary is preferably added to facilitate molding.

In an alternative embodiment, the support may be prepared as disclosed in patent CN107029779A, in particular: (1) mixing the phosphorus-containing Y-type molecular sieve with heat-resistant inorganic oxide, peptizing agent, lubricant and water to obtain a mixture, wherein the dosage of each component is such that the weight ratio of the mass of the peptizing agent to the powder in the mixture is 0.28 x 10^-4～4.8×10^-4mol/g, the ratio of the weight of water to the amount of mass of peptizing agent is 2.0X 10³～30×10³g/mol, wherein the weight of the powder is the sum of the weights of the phosphorus-containing Y-type molecular sieve and the heat-resistant inorganic oxide, and the mass of the peptizing agent refers to the mole number of the metered H protons in the peptizing agent; the lubricant is one or two of sesbania powder and graphite; (2) and (2) kneading, molding, drying and roasting the mixture obtained in the step (1) to obtain the carrier.

The metal precursors may include a first metal precursor and a second metal precursor. Wherein the first metal precursor is a soluble compound containing the first metal, and comprises at least one of an inorganic acid of the first metal, an inorganic salt of the first metal and a first metal organic compound; the inorganic salt may be at least one selected from the group consisting of nitrate, carbonate, hydroxycarbonate, hypophosphite, phosphate, sulfate and chloride; the organic substituent in the first metal organic compound is at least one selected from hydroxyl, carboxyl, amino, ketone, ether and alkyl. For example, when the first metal is molybdenum, the first metal precursor may be at least one selected from the group consisting of molybdic acid, paramolybdic acid, molybdate, paramolybdate, and the like; when the first metal component is tungsten, the first metal precursor may be at least one selected from tungstic acid, metatungstic acid, ethyl metatungstic acid, tungstate, metatungstate, and ethyl metatungstate. The second metal precursor is a soluble compound containing the second metal and comprises at least one of inorganic acid of the second metal, inorganic salt of the second metal and organic compound of the second metal; the inorganic salt may be at least one selected from the group consisting of nitrate, carbonate, hydroxycarbonate, hypophosphite, phosphate, sulfate and chloride; the organic substituent in the second metal organic compound is at least one selected from hydroxyl, carboxyl, amino, ketone, ether and alkyl.

The impregnation liquid can also contain organic additives; the concentration of the organic additive may be 2-300 g/L. The organic additive is an oxygen-containing organic compound and/or a nitrogen-containing organic compound. Specifically, the oxygen-containing organic compound may be at least one selected from the group consisting of ethylene glycol, glycerol, polyethylene glycol (molecular weight may be 200 to 1500), diethylene glycol, butanediol, acetic acid, maleic acid, oxalic acid, nitrilotriacetic acid, 1, 2-cyclohexanediaminetetraacetic acid, citric acid, tartaric acid, and malic acid; the nitrogen-containing organic compound may be at least one selected from the group consisting of ethylenediamine, diethylenetriamine, cyclohexanediaminetetraacetic acid, glycine, nitrilotriacetic acid, ethylenediaminetetraacetic acid and ammonium ethylenediaminetetraacetate.

The contacting temperature in the preparation of the hydrocracking catalyst is not particularly limited, and may be various temperatures that the impregnation solution can reach. The time for the impregnation is also not particularly limited as long as the catalyst carrier can be supported with the desired amount of the metal active component precursor. In general, the higher the impregnation temperature, the higher the concentration of the impregnation solution, and the shorter the time required to achieve the same impregnation amount (i.e., the weight difference between the catalyst support after impregnation and the catalyst support before impregnation); and vice versa. When the desired amount and conditions of impregnation are determined, one skilled in the art can readily select an appropriate impregnation time based on the teachings of the present disclosure. The present disclosure does not specifically require an impregnation method, which may be either a saturated impregnation or a supersaturated impregnation. The impregnation may be carried out under a sealed condition or in an open environment according to a conventional method in the art, and the loss of the aqueous solvent may or may not be replenished during the impregnation. Various gases, such as air, nitrogen, water vapor, etc., may be introduced during the impregnation process, or any new components may not be introduced.

In the preparation of the hydrocracking catalyst, the drying conditions are not particularly limited, and may be various drying conditions commonly used in the art, for example, may be: the temperature is 80-350 ℃, preferably 100-300 ℃ and the time is 0.5-24 hours, preferably 1-12 hours.

In the preparation of the hydrocracking catalyst, a step of drying the contacted material and then calcining the dried material, which is a conventional step for preparing the catalyst, may be further included, and the disclosure is not particularly limited. The conditions for the calcination may be, for example: the temperature is 350-600 ℃, and preferably 400-550 ℃; the time is 0.2 to 12 hours, preferably 1 to 10 hours.

The following examples further illustrate the process of the present invention, but are not intended to limit the invention thereto.

The pore volume and specific surface area of the molecular sieve were measured by a static low-temperature adsorption capacity method using an ASAP 2400 model automatic adsorption apparatus (micromeritics instruments, USA) (using the method of national Standard GB/T5816-1995).

The unit cell constant is determined by an X-ray diffractometer model D5005 of Siemens Germany, and is in accordance with the method of industry standard SH/T0339-92.

The phosphorus content and the sodium content of the molecular sieve are measured by a 3271E type X-ray fluorescence spectrometer of Japan science and Motor industry Co., Ltd, and the measuring method comprises the following steps: tabletting and forming a powder sample, carrying out rhodium target, detecting the spectral line intensity of each element by a scintillation counter and a proportional counter under the laser voltage of 50kV and the laser current of 50mA, and carrying out quantitative and semi-quantitative analysis on the element content by an external standard method.

The ratio of the B acid amount to the L acid amount of the molecular sieve is measured by a Bio-Rad IFS-3000 type infrared spectrometer. The specific method comprises the following steps: the molecular sieve sample is ground and pressed into 10mg/cm²The self-supporting sheet is placed in an in-situ cell of an infrared spectrometer at 350 ℃ and 10 DEG C^-3Surface purification treatment is carried out for 2 hours under Pa vacuum degree, pyridine saturated steam is introduced after the surface purification treatment is carried out to the room temperature, after adsorption equilibrium is carried out for 15 minutes, vacuum desorption is carried out for 30 minutes at 350 ℃, and the adsorption and determination of pyridine vibration spectrum are measured after the surface purification treatment is carried out to the room temperature. The scanning range is 1400cm^-1-1700cm^-1At 1540 + -5 cm^-1The ratio of the infrared absorption of the band to the weight and area of the sample piece defines the amount of B acid [ infrared absorption per unit area, per unit mass of the sample, expressed as: AB (cm)²·g)^-1]. At 1450 + -5 cm^-1The ratio of the infrared absorption value of the band to the weight and area of the sample piece defines the L acid amount [ infrared absorption value per unit area, unit mass of the sample, expressed as: AL (cm)²·g)^-1]The value of AB/AL is defined as the ratio of the amount of B acid to the amount of L acid of the zeolite molecular sieve.

The molecular sieve adopts a Varian UNITYINOVA300M nuclear magnetic resonance instrument to perform sample analysis, wherein the resonance frequency of Al MAS is 78.162MHzs, the rotor speed is 3000Hz, the repetition delay time is 0.5s, the sampling time is 0.020s, the pulse width is 1.6 mus, the spectrum width is 54.7kHz, the data is collected at 2000 points, the cumulative frequency is 800 times, and the test temperature is room temperature.

Example 1

The hydrocracking catalyst A is prepared by the following method:

taking PSRY molecular sieve (product of China petrochemical catalyst Chang Ling division, trade name PSRY, unit cell constant of 2.456nm, specific surface area of 620 m)²Per g, pore volume of 0.39ml/g, Na₂O content 2.2 wt.%, P₂O₅Content of 1.5 wt.%, Al₂O₃Content of 18 wt%) of the phosphorus-containing molecular sieve, adding deionized water, pulping, wherein the total amount of water is 1000ml, filtering, and drying at 70 ℃ for 2h to obtain the phosphorus-containing molecular sieve raw material with the water content of 35 wt%.

Crushing the phosphorus-containing molecular sieve raw material, sieving to 5-20 meshes (wherein 1-500 mm particles account for 70 wt% of the total weight of the phosphorus-containing molecular sieve raw material), placing into a hydrothermal treatment device, introducing 100% of steam, heating to 580 ℃, controlling the pressure in the device to be 0.4MPa, performing hydrothermal treatment for 2 hours constantly, and taking out the molecular sieve material after the hydrothermal treatment.

According to the weight ratio of sulfuric acid to phosphorus-containing molecular sieve raw material (dry basis) of 0.02: 1 preparing 250ml of sulfuric acid aqueous solution, wherein the concentration of sulfuric acid in the aqueous solution is 0.2 mol/L.

Taking 50g (dry basis) of the molecular sieve material subjected to the hydrothermal treatment, adding 500ml of deionized water, stirring and pulping to obtain molecular sieve slurry, and heating to 80 ℃. Based on 1L of molecular sieve slurry and H⁺Adding the prepared sulfuric acid aqueous solution into the molecular sieve slurry at a constant speed for three times at a speed of 0.5mol/h, reacting for 2 hours at a constant temperature after each time of acid addition, filtering, and taking a filter cake to continue to add acid for the next time in the same manner. After the last time of acid addition and reaction for 2 hours, collecting a solid product, and drying at 100 ℃ for 8 hours to obtain the phosphorus-containing Y-type molecular sieve Y-1, wherein the phosphorus content is 0.6 weight percent, the pore volume is 0.38ml/g, the acid content of B acid/L acid content is 4.2, I_60ppm/I_-1ppmIs 5.2, I_-1ppm/I_±6ppmIs 1.2.

583.3g of pseudo-boehmite powder PB90 (produced by Zhongpetrochemical catalyst ChangLing division, with a pore volume of 0.9ml/g and a water content of 28 wt%) and 98.8g Y-1 molecular sieve (with a water content of 19 wt%) and 18 g of sesbania powder are mixed uniformly, 580ml of aqueous solution containing 18ml of nitric acid (65-68 wt% in Beijing chemical reagent factory) is added, and extruded into trilobal strips with a circumscribed circle diameter of 1.6 mm, and the three-leaf strips are dried at 120 ℃ and calcined at 600 ℃ for 3 hours to obtain the carrier CS.

After the temperature is reduced to room temperature, 100g of CS carrier is taken and dipped in 80ml of aqueous solution containing 52 g of ammonium metatungstate (82 wt% of tungsten oxide in Sichuan tribute cemented carbide factory), 8.7 g of basic nickel carbonate (51 wt% of nickel oxide in Jiangsu Yixing brady chemical Co., Ltd.) and 10.5g of citric acid, and the carrier is baked for 10 hours at 120 ℃ to obtain the hydrocracking catalyst A, wherein the carrier comprises the following components: 84 wt% of heat-resistant oxide, 16 wt% of phosphorus-containing molecular sieve; catalyst composition, calculated as oxides: 29% by weight of tungsten, 3% by weight of nickel and 68% by weight of support.

The hydrocracking catalyst B in the comparative example was prepared by the following method:

the preparation method of the phosphorus-containing molecular sieve in the hydrocracking catalyst in the comparative example can refer to the preparation method of the phosphorus-containing zeolite disclosed in CN1088407C, which comprises directly mixing a phosphorus-containing compound and a raw material zeolite in a weight ratio of 0.1-40, heating at 50-550 ℃ for at least 0.1 hour under a closed condition, washing the obtained product with deionized water until no acid radical ions exist, and obtaining the phosphorus-containing molecular sieve named as Y-2, wherein the phosphorus content is 2.3 wt%, the pore volume is 0.37ml/g, the acid content of B acid/L acid is 3.2, the acid content of I60ppm/I-1ppm is 5.5, and the acid content of I-1ppm/I ± 6ppm is 2.7.

Hydrocracking catalyst B was prepared according to the method of example 1, with the difference that the molecular sieve used was Y-2, yielding a hydrocracking catalyst B with a support composition of: 84 wt% of heat-resistant oxide, 16 wt% of phosphorus-containing molecular sieve; catalyst composition, calculated as oxides: 29% by weight of tungsten, 3% by weight of nickel and 68% by weight of support.

The hydrocracking catalyst C has a commercial designation of RT-5. The commercial designations of the hydrofining catalyst I and the hydrofining catalyst II are RN-32V, and the hydrofining catalyst I and the hydrofining catalyst II are both produced by China petrochemical catalyst division.

VGO properties in the following examples and comparative examples are shown in Table 1.

Example 2

The mixture of raw oil and hydrogen sequentially passes through a first hydrogenation reaction zone, a second hydrogenation reaction zone and a third hydrogenation reaction zone to respectively contact with a hydrofining catalyst I, a hydrocracking catalyst A and a hydrofining catalyst II for reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation to obtain a naphtha fraction (<150 ℃), a aviation kerosene fraction (<150 ℃), a diesel fraction (< 270-. The reaction conditions, product distribution and key product properties are listed in tables 2 and 3.

As shown in tables 2 and 3, by adopting the method provided by the invention, under the condition of keeping the yield of the tail oil at the temperature of more than 330 ℃ to be about 24%, the yield of the aviation kerosene fraction reaches 41.37%, the aviation kerosene selectivity reaches 62.2%, the smoke point is 27.3mm, the freezing point is less than < -50 ℃, the key properties meet the requirements of 3# jet fuel, the cetane index of the diesel oil fraction is up to more than 65, and in addition, the BMCI value of the tail oil is 7.9, so that the tail oil can be used as a high-quality ethylene cracking raw material.

Example 3

The mixture of raw oil and hydrogen sequentially passes through a first hydrogenation reaction zone, a second hydrogenation reaction zone and a third hydrogenation reaction zone to respectively contact with a hydrofining catalyst I, a hydrocracking catalyst A and a hydrofining catalyst II for reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation to obtain a naphtha fraction (<150 ℃), a aviation kerosene fraction (<150 ℃), a diesel fraction (< 270-. 50% of the tail oil fraction, by weight of the total tail oil fraction, is recycled to the third hydrogenation reaction zone. The reaction conditions, product distribution and key product properties are listed in tables 2 and 3.

As shown in tables 2 and 3, by adopting the method provided by the invention, under the condition of keeping the yield of the tail oil at the temperature of more than 330 ℃ to be about 24%, the yield of the aviation kerosene fraction reaches 41.51%, the aviation kerosene selectivity reaches 62.1%, the smoke point is 27.3mm, the freezing point is less than < -50 ℃, the key properties meet the requirements of 3# jet fuel, the cetane index of the diesel oil fraction is up to more than 65, and in addition, the BMCI value of the tail oil is 7.5, so that the tail oil can be used as a high-quality ethylene cracking raw material. The tail oil obtained in example 3 was better in quality than in example 2.

Comparative example 1

The mixture of raw oil and hydrogen sequentially passes through a first hydrogenation reaction zone, a second hydrogenation reaction zone and a third hydrogenation reaction zone to respectively contact with a hydrofining catalyst I, a hydrocracking catalyst B and a hydrofining catalyst II for reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation to obtain a naphtha fraction (<150 ℃), a aviation kerosene fraction (<150 ℃), a diesel fraction (> 270-. The reaction conditions, product distribution and key product properties are listed in tables 2 and 3.

As shown in tables 2 and 3, the yield and selectivity of aviation kerosene fraction after the feedstock oil had been prepared by the method provided in comparative example 2 were similar to those of example 2, while maintaining the yield of tail oil at >330 ℃ of about 24%, but requiring a higher hydrocracking reaction temperature (about 10 ℃ higher). Although the product quality is satisfactory, higher reaction temperatures can affect the operating cycle of the plant.

Comparative example 2

The mixture of raw oil and hydrogen passes through the first hydrogenation reaction zone and the second hydrogenation reaction zone in sequence and is respectively contacted with a hydrofining catalyst I and a hydrocracking catalyst B for reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation to obtain a naphtha fraction (<150 ℃), a aviation kerosene fraction (<150 ℃), a diesel fraction (> 270-. The reaction conditions, product distribution and key product properties are listed in tables 2 and 3.

As shown in tables 2 and 3, the yield and selectivity of aviation kerosene fraction after the feedstock oil had been processed by the method provided in comparative example 2 was similar to that of example 1, but higher hydrocracking reaction temperature was required (reaction temperature was about 10 ℃ C. higher), while maintaining the yield of tail oil at >330 ℃ of about 24%. In addition, because no third hydrogenation reaction zone is set up, the quality of the tail oil of the product is relatively poor, and the BMCI value is 8.6.

Comparative example 3

The mixture of raw oil and hydrogen sequentially passes through a first hydrogenation reaction zone, a second hydrogenation reaction zone and a third hydrogenation reaction zone to respectively contact with a hydrofining catalyst I, a hydrocracking catalyst C and a hydrofining catalyst II for reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation to obtain a naphtha fraction (<150 ℃), a aviation kerosene fraction (<150 ℃), a diesel fraction (> 270-. The reaction conditions, product distribution and key product properties are listed in tables 2 and 3.

As shown in tables 2 and 3, the yield and selectivity of aviation kerosene fraction were much lower than those of example 2, the yield of aviation kerosene was about three percentage points lower, and the selectivity of aviation kerosene was about five percentage points lower, while maintaining the yield of tail oil of >330 ℃ of about 24%, after the feedstock oil was prepared by the method provided in comparative example 3, although the reaction temperature and the volume space velocity were comparable to those of example 2. In addition, the BMCI value of the obtained tail oil was 8.7, which is higher than that of example 2.

The results show that the method provided by the invention can obtain high-yield aviation kerosene under the conditions of relatively low reaction temperature or relatively high airspeed and relatively equivalent yield of tail oil, and the product quality is relatively excellent.

TABLE 1 Properties of the raw materials

Item
		Density (20 ℃ C.)/(g/cm)³)	0.9058
Sulfur mass fraction/%	2.47
		Mass fraction of nitrogen/(μ g/g)	753
Distillation range (D-1160)/. deg.C
		Initial boiling point	207
10％	346
		30％	399
50％	425
		70％	443
90％	477
		95％	497

TABLE 2 Process conditions and product distribution

Table 3 key product properties primary product properties

Claims

1. A hydrocracking process for producing chemical and fuel oils comprising: in the presence of hydrogen, raw oil sequentially passes through a first hydrogenation reaction zone, a second hydrogenation reaction zone and a third hydrogenation reaction zone for reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation to obtain naphtha fraction, aviation kerosene fraction, diesel fraction and tail oil fraction;

the hydrocracking catalyst comprises 45-90 wt% of a carrier, 1-40 wt% of a first metal component and 1-15 wt% of a second metal component, wherein the carrier is calculated by the weight of the hydrocracking catalyst on a dry basis, and the first metal component is calculated by the weight of a metal oxide; the carrier comprises a phosphorus-containing Y-type molecular sieve and a heat-resistant inorganic oxide, wherein the weight ratio of the phosphorus-containing Y-type molecular sieve to the heat-resistant inorganic oxide is (0.03-20): 1, the first metal component is a metal selected from group VIB; the second metal component is a metal selected from a VIII group, and calculated by oxides, the phosphorus content of the phosphorus-containing Y-type molecular sieve is 0.3-5 wt%, the pore volume is 0.2-0.95 mL/g, and the ratio of pyridine infrared B acid to pyridine infrared L acid is 2-10; the preparation method of the phosphorus-containing Y-type molecular sieve comprises the following steps:

2. The method of claim 1, wherein in the step a, the phosphorus-containing molecular sieve raw material is a phosphorus-containing Y-type molecular sieve, the unit cell constant of the phosphorus-containing Y-type molecular sieve is 2.425-2.47 nm, and the specific surface area is 250-750 m²The pore volume is 0.2-0.95 ml/g;

the water content of the phosphorus-containing molecular sieve raw material is 10-40 wt%.

3. The method of claim 1, wherein the phosphorus-containing molecular sieve feedstock is in the form of particles, and the content of the phosphorus-containing molecular sieve feedstock having a particle size ranging from 1mm to 500mm is 10 to 100 wt% of the total weight of the phosphorus-containing molecular sieve feedstock, the particle size being based on the diameter of the circumscribed circle of the particles.

4. The method of claim 1, wherein in the step b, the ratio of the weight of water in the molecular sieve slurry obtained after beating to the dry weight of the phosphorus-containing molecular sieve raw material is (14-5): 1.

5. the method according to claim 1, wherein in the step b, the acid solution has an acid concentration of 0.01 to 15.0mol/L, and the acid is at least one selected from phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, citric acid, tartaric acid, formic acid and acetic acid.

6. The method according to claim 1, wherein the heat-resistant inorganic oxide is at least one selected from the group consisting of alumina, zirconia, magnesia, thoria, beryllia, boria, and cadmium oxide; the first metal component is molybdenum and/or tungsten; the second metal component is at least one selected from iron, nickel and cobalt.

7. The process of claim 1, wherein the reaction conditions of the first hydrogenation reaction zone are: hydrogen partial pressure of 6.0 MPa-20.0 MPa, reaction temperature of 280 ℃ to EAt 420 ℃, the liquid hourly space velocity is 0.5h^-1～6h^-1The volume ratio of hydrogen to oil is 300-2000;

the reaction conditions of the second hydrogenation reaction zone are as follows: the hydrogen partial pressure is 6.0MPa to 20.0MPa, the reaction temperature is 290 ℃ to 420 ℃, and the liquid hourly space velocity is 0.3h^-1～5h^-1The volume ratio of hydrogen to oil is 300-2000;

the reaction conditions of the third hydrogenation reaction zone are as follows: the hydrogen partial pressure is 6.0MPa to 20.0MPa, the reaction temperature is 280 ℃ to 420 ℃, and the liquid hourly space velocity is 1h^-1～15h^-1The volume ratio of hydrogen to oil is 300-2000.

8. The process of claim 7, wherein the reaction conditions in the first hydrogenation reaction zone are: the hydrogen partial pressure is 7.0MPa to 15.0MPa, the reaction temperature is 290 ℃ to 390 ℃, and the liquid hourly space velocity is 0.8h^-1～5h^-1The volume ratio of hydrogen to oil is 300-1800;

the reaction conditions of the second hydrogenation reaction zone are as follows: the hydrogen partial pressure is 7.0MPa to 15.0MPa, the reaction temperature is 300 ℃ to 410 ℃, and the liquid hourly space velocity is 0.3h^-1～4h^-1The volume ratio of hydrogen to oil is 300-1800;

the reaction conditions of the third hydrogenation reaction zone are as follows: the hydrogen partial pressure is 7.0MPa to 15.0MPa, the reaction temperature is 280 ℃ to 400 ℃, and the liquid hourly space velocity is 1.5h^-1～10h^-1The volume ratio of hydrogen to oil is 300-1800.

9. The process of claim 1, wherein hydrofinishing catalyst I and hydrofinishing catalyst II are at least one catalyst selected from a group VIB non-noble metal, or at least one catalyst selected from a group VIII non-noble metal, or a combination thereof, supported on alumina or/and silica-alumina.

10. The process of claim 9, wherein the group VIII non-noble metal is selected from nickel and/or cobalt, the group VIB non-noble metal is selected from molybdenum and/or tungsten, the total content of nickel and/or cobalt in terms of oxides is 1-15 wt%, the total content of molybdenum and/or tungsten in terms of oxides is 5-40 wt%, and the balance is a support, based on the total weight of the hydrofinishing catalyst I or hydrofinishing catalyst II.

11. The process of claim 1 wherein at least 50 weight percent of the tail oil fraction, based on the total tail oil fraction, is recycled back to the third hydrogenation reaction zone.