Fluidized bed coal tar hydrotreating method

Abstract

The invention provides a fluidized bed coal tar hydrotreating method, which comprises the following steps: mixing a coal tar raw material with hydrogen, sequentially passing through a first fluidized bed hydrogenation reaction zone and a second fluidized bed hydrogenation reaction zone, filling a hydrogenation catalyst A in the first fluidized bed hydrogenation reaction zone, filling a hydrogenation catalyst B in the second fluidized bed hydrogenation reaction zone, separating the reaction effluent to obtain naphtha, diesel oil and aviation kerosene; wherein the bulk carbon content of the hydrogenation catalyst A is 5-20wt% higher than that of the hydrogenation catalyst B; the average pore size of the hydrogenation catalyst A is 5-15nm higher than that of the hydrogenation catalyst B; the total acid content of the hydrogenation catalyst A is 0.10-0.30 mmol / g lower than the total acid content of the hydrogenation catalyst B. The method can reduce the crushing of the catalyst and ensure the stable long-period operation of the device, and is especially suitable for the hydrotreating process of coal tar with high oxygen content; according to the method, hydrogenation reaction of the coal tar under the condition of high conversion rate can be realized, and meanwhile, the product quality and yield are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of petrochemical industry, and relates to a coal tar hydroprocessing method, in particular to a boiling bed coal tar hydroprocessing method. BACKGROUND

[0002] The general characteristics of China's energy endowment are "rich in coal, short of oil, and less gas", and the clean and efficient use of coal is an important measure to optimize energy structure, ensure energy security, and improve environmental quality. As a major part of coal-based fuels, coal tar has a high content of asphaltene and gum of more than 65wt%, and has the characteristics of high aromatic hydrocarbons, high olefins, and high metal impurities. Coal tar hydrogenation technology can convert low-quality coal tar into high-quality petroleum products, realize comprehensive utilization of resources, and reduce energy waste.

[0003] Traditional coal tar hydrogenation technology mostly adopts fixed bed hydrogenation, but this processing method has high hydrogen consumption and large reaction heat, and has high operation difficulty. The boiling bed hydrogenation technology has the advantages of uniform temperature in the reactor, long running period, and flexible device operation, and has obvious advantages in the coal tar hydrogenation process. CN104593060A discloses a coal tar boiling bed hydrogenation method. The method is that the coal tar raw material is first subjected to hydro-upgrading, then water is removed by separation, and then is subjected to hydrofining, and gasoline fraction, diesel fraction and hydrofining tail oil are obtained by fractionation. The hydro-upgrading catalyst composition used therein includes hydroxyl iron oxide, organic polycarboxylic acid, large-pore alumina, molecular sieve and pseudo-boehmite, and the hydrofining catalyst composition includes hydroxyl iron oxide, organic polycarboxylic acid, large-pore alumina and a binder. The present application uses low-cost hydroxyl iron oxide as the active metal component of the hydro-upgrading catalyst and the hydrofining catalyst, and the cost is low, and the product distribution and product properties can be effectively removed by the hydro-upgrading and then the refining of the coal tar, thereby adjusting the product distribution and product properties. However, the oxygen content in the coal tar is high, and water is generated in the hydrogenation process. The hydro-upgrading catalyst and the hydrofining catalyst used in the above patent are both supported on alumina, and when they are applied to the coal tar hydrogenation process, hydration reaction is easy to occur, which causes the strength of the catalyst to decrease, and even the catalyst is broken, thereby affecting the running period of the device. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a boiling bed coal tar hydroprocessing method. The method can reduce the breaking of the catalyst, ensure the stable and long-period operation of the device, and is especially suitable for the coal tar hydroprocessing process with high oxygen content; the method can realize the hydrogenation reaction of the coal tar under the condition of high conversion rate, and improve the product quality and yield.

[0005] A boiling bed coal tar hydroprocessing method, comprising the following contents: coal tar raw material is mixed with hydrogen, and then sequentially passes through a first boiling bed hydroreaction zone and a second boiling bed hydroreaction zone, the first boiling bed hydroreaction zone is filled with a hydrogenation catalyst A, the second boiling bed hydroreaction zone is filled with a hydrogenation catalyst B, and a reaction effluent is separated to obtain naphtha, diesel oil and aviation kerosene;

[0006] Wherein, compared with the hydrogenation catalyst B, the bulk carbon content of the hydrogenation catalyst A is 5-20wt% higher than that of the hydrogenation catalyst B, preferably 10-15wt% higher; the average pore size of the hydrogenation catalyst A is 5-15nm higher than that of the hydrogenation catalyst B, preferably 7-10nm higher; and the total acid content of the hydrogenation catalyst A is 0.10-0.30mmol / g lower than that of the hydrogenation catalyst B, preferably 0.15-0.28mmol / g lower.

[0007] In the above method, the density (20℃) of the coal tar raw material is 0.85-1.15g·cm 3 , the sulfur content is 0.15-0.35wt%, the nitrogen content is 0.80-1.10wt%, the oxygen content is 6.0-12.0wt%, and the carbon residue content is 4.0-10.0wt%.

[0008] In the above method, at least one boiling bed hydroreactor is arranged in the first boiling bed hydroreaction zone and the second boiling bed hydroreaction zone, preferably one boiling bed hydroreactor is arranged in each of the first boiling bed hydroreaction zone and the second boiling bed hydroreaction zone; the boiling bed hydroreactor can adopt any one of the existing boiling bed reactors in the art, preferably a STRONG boiling bed reactor with an internal three-phase separator developed by SINOPEC (Dalian) Petroleum Chemical Research Institute Co., Ltd.

[0009] In the above method, the hydrogenation catalyst A comprises a carrier and a hydrogenation active metal component supported on the carrier, wherein the carrier comprises alumina and carbon, the hydrogenation active metal component comprises a Group VIB metal component and a Group VIII metal component, the Group VIII metal is Ni and / or Co, and the Group VIB metal is W and / or Mo; the content of the Group VIB metal in terms of oxide is 3wt%-9wt% based on the weight of the catalyst, and the content of the Group VIII metal in terms of oxide is 0.5wt%-3wt% based on the weight of the catalyst.

[0010] In the above method, the bulk carbon content of the hydrogenation catalyst A is 35-50wt% based on the weight of the catalyst, preferably 38-45wt%; the average pore size is 15-30nm, preferably 17-25nm; and the total acid content is 0-0.40mmol / g, preferably 0.05-0.35mmol / g.

[0011] In the above method, the hydrogenation catalyst A has a surface carbon content of 35-50 wt%, preferably 38-45 wt%, based on the weight of the catalyst; preferably, the bulk carbon content and the surface carbon content differ by no more than 5 wt%, preferably no more than 3 wt%.

[0012] In the above method, the hydrogenation catalyst B comprises a carrier and a hydrogenation active metal component supported on the carrier, wherein the carrier comprises alumina and carbon, the hydrogenation active metal component comprises a Group VIB metal component and a Group VIII metal component, wherein the Group VIII metal is Ni and / or Co, and the Group VIB metal is W and / or Mo; the content of the Group VIB metal in terms of oxide is 8-20 wt%, and the content of the Group VIII metal in terms of oxide is 1-9 wt%, based on the weight of the catalyst.

[0013] In the above method, the hydrogenation catalyst B has a bulk carbon content of 25-40 wt%, preferably 28-35 wt%, based on the weight of the catalyst; an average pore size of 5-15 nm, preferably 8-13 nm; and a total acid content of greater than 0.5 mmol / g, preferably 0.55-0.65 mmol / g.

[0014] In the above method, the hydrogenation catalyst B has a surface carbon content of 25-40 wt%, preferably 28-35 wt%, based on the weight of the catalyst; preferably, the bulk carbon content and the surface carbon content differ by no more than 5 wt%, preferably no more than 3 wt%.

[0015] In the above method, the hydrogenation catalyst A and the hydrogenation catalyst B can both contain an auxiliary agent according to the use requirements of the catalyst, the auxiliary agent being one or more of P, B, Ti and Zr; the auxiliary agent is added in an amount of 5 wt% or less based on the weight of the catalyst in terms of elements.

[0016] In the above method, the operating conditions used in the first ebullated bed hydrogenation reaction zone and the second ebullated bed hydrogenation reaction zone are generally as follows: the reaction pressure is 10-20 MPa, the temperature is 400-500°C, the liquid hourly space velocity is 0.1-5.0 h -1 , and the hydrogen / oil volume ratio is 100-1000.

[0017] Compared with the prior art, the ebullated bed coal tar hydroprocessing method provided by the application has the following advantages:

[0018] In the method, the coal tar raw material passes through the first ebullated bed hydrogenation reaction zone and the second ebullated bed hydrogenation reaction zone in sequence, the first ebullated bed hydrogenation reaction zone is filled with hydrogenation catalyst A, and the second ebullated bed hydrogenation reaction zone is filled with hydrogenation catalyst B. Compared with the hydrogenation catalyst B, the hydrogenation catalyst A has higher bulk carbon content, and the high carbon content of the hydrogenation catalyst A is beneficial to improving the water resistance of the catalyst, avoiding the influence of water generated in the coal tar hydrogenation reaction process on the catalyst, avoiding the crushing of the catalyst, preventing the catalyst from being taken out, and ensuring the stable long-period operation of the device. The hydrogenation catalyst A has high average pore size, has strong metal capacity, is beneficial to the contact between macromolecular reactants in the coal tar and active centers, is beneficial to deep removal of impurities, and improves the product quality. The catalysts filled in the first and second ebullated bed hydrogenation reaction zones have gradient distribution of acidity, can realize the step-by-step hydrogenolysis of the coal tar, and are beneficial to improving the conversion rate. DETAILED DESCRIPTION

[0019] The application will be further described by examples and comparative examples, and the use range of the application is not limited. The end points and any value of the disclosed range are not limited to the exact range or value, and the range or value should be understood as containing values close to the range or value. For the numerical range, the end points of each range, the end points of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed herein. The content in the following examples is weight percentage unless otherwise specified.

[0020] In the application, the preparation method of the hydrogenation catalyst A comprises the following steps:

[0021] a. preparing an alumina-carbon composite material;

[0022] b. forming the alumina-carbon composite material obtained in step a to obtain a carrier;

[0023] c. introducing an active metal component to the carrier obtained in step b, and drying and calcining to obtain the final hydrogenation catalyst A.

[0024] In the application, the preparation method of the hydrogenation catalyst B comprises the following steps:

[0025] S1. preparing an alumina-carbon composite material;

[0026] S2. performing surface modification treatment on the alumina-carbon composite material obtained in step S1, and then forming the alumina-carbon composite material to obtain a carrier;

[0027] S3. introducing an active metal component to the carrier obtained in step S2, and drying and calcining to obtain the final hydrogenation catalyst B;

[0028] The surface modification treatment in step S2 is carried out by contacting the alumina-carbon composite material obtained in step S1 with an acidic solution. The contacting treatment is carried out at a temperature of 60-150°C, preferably 80-120°C, for 1-4 hours, preferably 1.5-3 hours. The acidic solution is an inorganic acid selected from one or more of hydrochloric acid, nitric acid and sulfuric acid, preferably nitric acid. The concentration of the acidic solution is 5-20 wt%, preferably 8-15 wt%.

[0029] In the above method, the preparation method of the alumina-carbon composite material comprises the following steps:

[0030] (1) mixing an aluminum source with an organic solvent to obtain a first material;

[0031] (2) mixing the first material obtained in step (1) with a carbon source and then performing heat treatment to obtain a second material;

[0032] (3) performing carbonization treatment on the second material obtained in step (2) to obtain an alumina-carbon composite material.

[0033] Further, the aluminum source in step (1) is an organic aluminum-containing compound, and the specific aluminum source can be selected from one or more of aluminum isopropoxide, aluminum n-butoxide, triethylaluminum and aluminum n-hexoxide, preferably aluminum isopropoxide.

[0034] Further, the organic solvent in step (1) is selected from one or more of catalytic diesel oil, isopropyl alcohol, n-butyl alcohol, n-hexyl alcohol, petroleum ether and diethyl ether, preferably catalytic diesel oil and / or isopropyl alcohol.

[0035] Further, the mass ratio of the aluminum source to the organic solvent in step (1) is 1:(2-15), preferably 1:(5-10).

[0036] Further, the carbon source in step (2) is one or more of natural asphalt, petroleum asphalt and coal tar pitch, preferably coal tar pitch.

[0037] Further, the mass ratio of the carbon source in step (2) to the aluminum source in step (1) is 1:0.5-50, preferably 1:1-10, by mass.

[0038] Further, the heat treatment temperature in step (2) is 80-180°C, preferably 110-160°C, and the heat treatment time is 15-90 minutes, preferably 30-60 minutes.

[0039] Further, an auxiliary agent can be introduced in step (2), and the introduction process is as follows: the auxiliary agent is mixed with the first material obtained in step (1) and the carbon source, and then heat treatment is performed; the auxiliary agent is one or more of polyethylene glycol 200, polyethylene glycol 400 and polyethylene glycol 600, and preferably polyethylene glycol 200; the mass ratio of the auxiliary agent to the carbon source is (5-20):100, and preferably (8-15):100.

[0040] Further, according to a preferred embodiment of the present application, the carbonization treatment in step (3) is performed in the presence of an inert atmosphere, which is one or more of nitrogen, carbon dioxide and inert gas, and preferably carbon dioxide; the inert gas is one or more of helium, neon, argon, krypton and xenon; the carbonization treatment temperature is 350-1000°C, and preferably 500-800°C; and the carbonization treatment time is 2-6 hours, and preferably 2.5-4 hours.

[0041] Further, according to a preferred embodiment of the present application, the carbonization treatment in step (3) preferably further comprises a pre-carbonization treatment, which is performed in the presence of air or oxygen; the pre-carbonization treatment temperature is 350-500°C, and preferably 380-450°C; and the pre-carbonization treatment time is 30-90 minutes, and preferably 40-70 minutes.

[0042] Further, an expansion agent can be introduced in step (3), and the process is as follows: the second material obtained in step (2) is mixed with the expansion agent, and then carbonization treatment is performed; the expansion agent is one or more of urea, ammonium bicarbonate, ammonium carbonate and melamine, and preferably ammonium bicarbonate; and the mass ratio of the expansion agent to the second material is (0.5-10):100.

[0043] In the above method, the shaping can adopt any one of the existing shaping methods in the art, and the shape of the carrier obtained after shaping can be any one of a cylindrical bar shape, a spherical shape, a tooth ball shape and a multi-leaf grass shape.

[0044] In the above method, the active metal component is selected from at least one metal in Group VIB and at least one metal in Group VIII of the periodic table, and preferably the metal in Group VIB is Mo and / or W, and the metal in Group VIII is Ni and / or Co.

[0045] In the above method, the method for introducing the active metal component can adopt any one of impregnation and kneading, and preferably impregnation. When impregnation is adopted, any one of spray impregnation, saturated impregnation and supersaturated impregnation can be adopted. The specific operation process is as follows: first, the precursor of the active metal component, water and an optional phosphorus-containing compound are mixed uniformly to obtain a solution containing the active metal, and then the carrier is immersed in the solution containing the active metal.

[0046] In the above method, the drying temperature is 90-120℃, the drying time is 2-10h; the calcination temperature is 500-800℃, and the calcination time is 4-10h.

[0047] The method provided by the present application will be further described below in combination with examples, but the present application is not limited by this.

[0048] In the context of the present specification, the acid content is measured by pyridine infrared adsorption method.

[0049] In the context of the present specification, the average pore size is measured by low-temperature nitrogen adsorption method.

[0050] In the context of the present specification, the bulk carbon content is measured by high-frequency combustion infrared absorption method, and the test method is performed according to the chemical industry standard HG / T 5594-2019. The surface carbon content is measured by x-ray photoelectron spectroscopy (XPS), and the x-ray photoelectron spectroscopy analysis (XPS) is analyzed by Shimadzu Kratos X-ray photoelectron spectrometer AXIS SPURA+, using AlKα photoelectron source, Eb=1486.6eV, and all binding energies are corrected with respect to the contaminant carbon (C1s 284.8eV) as the reference.

[0051] In the examples and comparative examples of the present application, the density of coal tar pitch used is 1.05kg / L, the carbon content is 85wt%, the hydrogen content is 7.5wt%, the nitrogen content is 0.8wt%, and the sulfur content is 3.9wt%; the density of petroleum pitch is 1.02kg / L, the carbon content is 81wt%, the hydrogen content is 8.1wt%, the nitrogen content is 0.7wt%, and the sulfur content is 4.1wt%.

[0052] In the examples and comparative examples of the present application, the density of catalytic diesel used is 0.897kg / m 3 , the aromatic hydrocarbon content is 39.7wt%, the S content is 0.13wt%, and the nitrogen content is 0.09wt%.

[0053] Example 1

[0054] Hydrogenation catalyst A: Alumina-carbon composite preparation: 2 kg of aluminum n-butoxide was dissolved in 10 L of catalytic diesel oil by stirring, 500 g of petroleum pitch and 100 g of polyethylene glycol 200 were added to the above solution, heated to 120°C, stirred at a stirring rate of 500 r / min for 45 min, then reduced to room temperature, and 100 g of urea was added and stirred for 5 min. The above mixed sample was subjected to pre-carbonization treatment under air atmosphere for 60 min, the pre-carbonization treatment temperature was 350°C, and then carbonization was carried out under carbon dioxide atmosphere for 3 h, the carbonization temperature was 750°C, to obtain a black powder product. The black powder was dried at 100°C for 4 h to obtain an alumina-carbon composite material SA1.

[0055] Take 500 g of the prepared SA1 sample, add 7 g of sesbania powder and 31.3 g of nitric acid (65 wt%), 410 g of water, mix well, then ball, and the balled sample is dried at 140°C for 5 h to obtain a carrier ZA1 with a particle size of 0.3-0.8 mm.

[0056] Take 500 g of the prepared SA1 sample, add 7 g of sesbania powder and 31.3 g of nitric acid (65 wt%), 410 g of water, mix well, then ball, and the balled sample is dried at 140°C for 5 h to obtain a carrier ZA1 with a particle size of 0.3-0.8 mm.

[0057] Hydrogenation catalyst B: Alumina-carbon composite preparation: 2 kg of aluminum n-butoxide was dissolved in 10 L of catalytic diesel oil by stirring, 500 g of petroleum pitch and 100 g of polyethylene glycol 200 were added to the above solution, heated to 120°C, stirred at a stirring rate of 500 r / min for 45 min, then reduced to room temperature, and 100 g of urea was added and stirred for 5 min. The above mixed sample was subjected to pre-carbonization treatment under air atmosphere for 60 min, the pre-carbonization treatment temperature was 350°C, and then carbonization was carried out under carbon dioxide atmosphere for 3 h, the carbonization temperature was 750°C, to obtain a black powder product. The black powder was dried at 100°C for 4 h to obtain an alumina-carbon composite material SA1.

[0058] Take 500 g of the prepared SA1 sample, add 7 g of sesbania powder and 31.3 g of nitric acid (65 wt%), 410 g of water, mix well, then ball, and the balled sample is dried at 140°C for 5 h to obtain a carrier ZA1 with a particle size of 0.3-0.8 mm.

[0059] Take phosphoric acid 78.88 g, add distilled water 800 mL, then add molybdenum oxide 185.68 g, basic cobalt carbonate 50.81 g, heat and stir until completely dissolved, then use distilled water to make the solution to 2000 mL, get solution L2. The carrier ZB1 is saturated with solution L2 solution, and is dried at 110°C for 4h, and is calcined at 500°C under nitrogen atmosphere to obtain catalyst CB1. The properties of CB1 are as follows: bulk carbon content 28.13wt%, surface carbon content 26.35wt%, average pore size 12.5 nm, acid content 0.65 mmol / g.

[0060] Example 2

[0061] Hydrogenation catalyst A: preparation of alumina-carbon composite: 2 kg of aluminum n-hexanol is dissolved in 10 L of catalytic diesel oil, 500 g of petroleum pitch and 100 g of polyethylene glycol 400 are added to the above solution, heated to 100°C, stirred at a stirring rate of 500 r / min for 45 min, then cooled to room temperature, and then 100 g of ammonium bicarbonate is added and stirred for 5 min. The above mixed sample is subjected to pre-carbonization treatment under air atmosphere for 30 min, and the pre-carbonization treatment temperature is 350°C. Then carbonization is carried out under carbon dioxide atmosphere for 3h, and the carbonization temperature is 600°C, to obtain a black powder product. The black powder is dried at 100°C for 4h to obtain an alumina-carbon composite SA2.

[0062] Take 500 g of the prepared SA2 sample, add 7 g of amaranth powder and 15.38 g of nitric acid (65wt%), and 450 g of water, mix well, then form a ball, and then the formed ball sample is dried at 120°C for 5h to obtain a carrier ZA2 with a particle size of 0.3-0.8 mm.

[0063] The carrier ZA2 is saturated with L1 solution, dried at 110°C for 2h, and calcined at 450°C under nitrogen atmosphere for 3h to obtain catalyst CA2. The specific properties of CA2 are as follows: bulk carbon content 39.42wt%, surface carbon content 38.87wt%, average pore size: 19.3 nm, total acid: 0.34 mmol / g.

[0064] Hydrogenation catalyst B: preparation of alumina-carbon composite: 2 kg of aluminum n-hexanol is dissolved in 10 L of catalytic diesel oil, 300 g of petroleum pitch is added to the above solution, heated to 120°C, and stirred at a stirring rate of 500 r / min for 45 min, then cooled to room temperature. The above mixed sample is carbonized under nitrogen atmosphere for 3h, and the carbonization temperature is 600°C, to obtain a black powder product. The black powder is dried at 100°C for 4h to obtain an alumina-carbon composite SB2.

[0065] Take 500g prepared SB2 sample in 10wt% hydrochloric acid heated to 100°C stirring 1 hour, get acidified alumina-carbon composite material, after suction filtration at 100°C drying 4h, add 7g of sesbania powder and nitric acid (65wt%) 31.3g, water 410g, mixed evenly and then into a ball type, the ball sample after drying at 140°C for 5h to get the particle size of 0.3-0.8mm carrier ZB2.

[0066] The carrier ZB2 is saturated with solution L2 solution, dried at 110°C for 4h, calcined at 500°C in nitrogen atmosphere to obtain catalyst CB2, CB2 properties as follows: bulk carbon content 28.41wt%, surface carbon content 26.18wt%, average pore size: 11.8nm, total acid: 0.61mmol / g.

[0067] Example 3

[0068] Hydrogenation catalyst A: alumina-carbon composite material preparation: 2kg aluminum n-butyl alcohol in 10L catalytic diesel oil stirring solution, add 500g petroleum pitch into the above solution, heated to 100°C, stirring rate of 500r / min stirring 45min after dropping to room temperature, then add 100g of ammonium bicarbonate stirring 5min. The above mixed sample in air atmosphere for pre-carbonization treatment 30min, pre-carbonization treatment temperature is 350°C, then in nitrogen atmosphere, carbonization 3h, carbonization temperature is 600°C, get black powder product. The black powder at 100°C drying 4h, get alumina-carbon composite material SA3.

[0069] Take 500g prepared SA3 sample, add 7g of sesbania powder and nitric acid (65wt%) 15.38g, water 450g, mixed evenly and then into a ball type, the ball sample after drying at 120°C for 5h to get the particle size of 0.3-0.8mm carrier ZA3.

[0070] The carrier ZA3 is saturated with L1 solution, dried at 110°C for 2h, calcined at 450°C in nitrogen atmosphere for 3h to obtain catalyst CA3, CA3 properties as follows: bulk carbon content 37.18wt%, surface carbon content 35.42wt%, average pore size: 19.1nm, total acid: 0.36mmol / g.

[0071] Hydrogenation catalyst B: same as example 2.

[0072] Example 4

[0073] Hydrogenation catalyst A: Alumina-carbon composite preparation: 2 kg of aluminum n-butoxide was dissolved in 10 L of catalytic diesel oil by stirring, 500 g of petroleum pitch was added to the above solution, heated to 100°C, stirred at a stirring rate of 500 r / min for 45 min, and then cooled to room temperature. The uniformly mixed sample was carbonized under a nitrogen atmosphere for 3 h at a carbonization temperature of 600°C to obtain a black powder product. The black powder was dried at 100°C for 4 h to obtain an alumina-carbon composite material SA4.

[0074] 500 g of the prepared SA4 sample was taken, 7 g of sesbania powder and 15.38 g of nitric acid (65 wt%) were added, and 450 g of water was added. After mixing, the sample was formed into a spherical shape, and the formed sample was dried at 120°C for 5 h to obtain a carrier ZA4 having a particle size of 0.3-0.8 mm.

[0075] Phosphoric acid 28.57 g was weighed, distilled water 800 mL was added, and then molybdenum oxide 77.58 g, basic nickel carbonate 35.56 g were sequentially added. After heating and stirring until completely dissolved, the solution was diluted to 1000 mL with distilled water to obtain a solution L1. The carrier ZA4 was saturatedly impregnated with the L1 solution, dried at 110°C for 2 h, and calcined at 450°C under a nitrogen atmosphere for 3 h to obtain a catalyst CA4, which had the following properties: bulk carbon content 36.48 wt%, surface carbon content 37.24 wt%, average pore diameter: 17.3 nm, total acid: 0.35 mmol / g.

[0076] Hydrogenation catalyst B: The same as Example 2.

[0077] Comparative Example 1

[0078] Hydrogenation catalyst A: Alumina-carbon composite preparation: 2 kg of aluminum n-butoxide was dissolved in 10 L of catalytic diesel oil by stirring, 500 g of petroleum pitch was added to the above solution, heated to 100°C, stirred at a stirring rate of 500 r / min for 45 min, and then cooled to room temperature. The uniformly mixed sample was carbonized under a nitrogen atmosphere for 3 h at a carbonization temperature of 600°C to obtain a black powder product. The black powder was dried at 100°C for 4 h to obtain an alumina-carbon composite material SA4.

[0079] 500 g of the prepared SA4 sample was taken, 7 g of sesbania powder and 15.38 g of nitric acid (65 wt%) were added, and 450 g of water was added. After mixing, the sample was formed into a spherical shape, and the formed sample was dried at 120°C for 5 h to obtain a carrier ZA4 having a particle size of 0.3-0.8 mm.

[0080] Take 28.57 g of phosphoric acid, add 800 mL of distilled water, then add 77.58 g of molybdenum oxide, 35.56 g of basic nickel carbonate, heat and stir until completely dissolved, then use distilled water to make the solution to 1000 mL, get solution Ll. The carrier ZKl is saturated with Ll solution, and is impregnated at 110°C for 2h, and is calcined at 450°C under nitrogen atmosphere for 3h to obtain catalyst CKl, CKl has the following properties: bulk carbon content 29.14wt%, surface carbon content 28.52wt%, average pore size: 13.9 nm, total acid: 0.32 mmol / g.

[0081] Hydrogenation catalyst B: same as example 2.

[0082] Comparative example 2

[0083] Hydrogenation catalyst A: preparation of alumina-carbon composite: 2 kg of aluminum n-butoxide is dissolved in 10 L of catalytic diesel oil, 500 g of petroleum pitch and 100 g of polyethylene glycol 200 are added to the above solution, heated to 120°C, stirred at a stirring rate of 500 r / min for 45 min, then cooled to room temperature, and then 100 g of urea is added and stirred for 5 min. The above mixed sample is carbonized under nitrogen atmosphere for 3h, and the carbonization temperature is 600°C, to obtain a black powder product. The black powder is dried at 100°C for 4h to obtain an alumina-carbon composite SK2.

[0084] Take 500 g of the prepared SK2 sample, add 7 g of amaranth powder and 15.38 g of nitric acid (65wt%), and 450 g of water, mix well, then form into a spherical shape, and then dry the spherical sample at 120°C for 5h to obtain a carrier ZK2 with a particle size of 0.3-0.8 mm.

[0085] Take 28.57 g of phosphoric acid, add 800 mL of distilled water, then add 77.58 g of molybdenum oxide, 35.56 g of basic nickel carbonate, heat and stir until completely dissolved, then use distilled water to make the solution to 1000 mL, get solution Ll. The carrier ZKl is saturated with Ll solution, and is impregnated at 110°C for 2h, and is calcined at 450°C under nitrogen atmosphere for 3h to obtain catalyst CKl, CKl has the following properties: bulk carbon content 29.14wt%, surface carbon content 28.52wt%, average pore size: 13.9 nm, total acid: 0.32 mmol / g.

[0086] Hydrogenation catalyst B: Preparation of alumina-carbon composite: 2 kg of aluminum n-butoxide was dissolved in 10 L of catalytic diesel oil by stirring, 300 g of petroleum pitch was added to the above solution, heated to 120°C, and stirred at a stirring rate of 500 r / min for 45 min, and then cooled to room temperature. The above mixed sample was carbonized under nitrogen atmosphere for 3 h at a carbonization temperature of 600°C to obtain a black powder product. The black powder was dried at 100°C for 4 h to obtain an alumina-carbon composite SL1.

[0087] Take 500 g of the prepared SL1 sample, add 7 g of amaranth powder and 31.3 g of nitric acid (65 wt%), 410 g of water, mix well, then ball, and then dry the balled sample at 140°C for 5 h to obtain a carrier ZL1 with a particle size of 0.3-0.8 mm.

[0088] Take 500 g of the prepared SL1 sample, add 7 g of amaranth powder and 31.3 g of nitric acid (65 wt%), 410 g of water, mix well, then ball, and then dry the balled sample at 140°C for 5 h to obtain a carrier ZL1 with a particle size of 0.3-0.8 mm.

[0089] The catalyst systems of Examples 1, 2, 3, 4 and Comparative Examples 1, 2 were compared in terms of activity in a CSTR. Two reactors were set up, a first reactor and a second reactor, wherein the first reactor was loaded with hydrogenation catalyst A and the second reactor was loaded with hydrogenation catalyst B. The properties of the raw oil are shown in Table 1; the evaluation conditions are shown in Table 2; and the evaluation results are shown in Table 3.

[0090] Table 1 Properties of raw oil

[0091]

[0092]

[0093] Table 2 Evaluation conditions

[0094] First reactor Second reactor Reaction temperature, °C 330 370 Reaction hydrogen partial pressure, MPa 15 15 Liquid hourly space velocity, h -1 ]] 0.35 0.4 Hydrogen to oil volume ratio 800：1 800：1

[0095] Table 3 Evaluation results

[0096] Removal rate, wt% Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 HDS 138 124 101 100 91 72 HDO 124 116 98 100 73 82 HD(Fe+Ca) 141 128 116 100 78 86 HDCCR 138 129 114 100 76 88

Claims

1. A method for hydrogenating coal tar in a fluidized bed, characterized in that: The process includes the following: after coal tar feedstock is mixed with hydrogen, it passes sequentially through the first fluidized bed hydrogenation reaction zone and the second fluidized bed hydrogenation reaction zone. The first fluidized bed hydrogenation reaction zone is filled with hydrogenation catalyst A, and the second fluidized bed hydrogenation reaction zone is filled with hydrogenation catalyst B. The reaction effluent is separated to obtain naphtha, diesel oil, and aviation kerosene. Compared with hydrogenation catalyst B, hydrogenation catalyst A has a bulk carbon content that is 5-20 wt% higher, preferably 10-15 wt% higher; the average pore size of hydrogenation catalyst A is 5-15 nm larger, preferably 7-10 nm larger; and the total acid content of hydrogenation catalyst A is 0.10-0.30 mmol / g lower, preferably 0.15-0.28 mmol / g lower, than that of hydrogenation catalyst B.

2. The method according to claim 1, characterized in that: The density (at 20°C) of the coal tar feedstock is 0.85-1.15 g·cm³. 3 The sulfur content is 0.15-0.35 wt%, the nitrogen content is 0.80-1.10 wt%, the oxygen content is 6.0-12.0 wt%, and the residual carbon content is 4.0-10.0 wt%.

3. The method according to claim 1, characterized in that: The first and second fluidized bed hydrogenation reaction zones are each equipped with at least one fluidized bed hydrogenation reactor, preferably one fluidized bed hydrogenation reactor in each zone; the fluidized bed hydrogenation reactor is any of the fluidized bed reactors existing in the art, preferably the STRONG fluidized bed reactor with a built-in three-phase separator developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd.

4. The method according to claim 1, characterized in that: The hydrogenation catalyst A comprises a support and a hydrogenation active metal component supported on the support, wherein the support comprises alumina and carbon, and the hydrogenation active metal component comprises a Group VIB metal component and a Group VIII metal component, wherein the Group VIII metal is Ni and / or Co, and the Group VIB metal is W and / or Mo; based on the weight of the catalyst, the content of the Group VIB metal as oxide is 3wt% to 9wt%, and the content of the Group VIII metal as oxide is 0.5wt% to 3wt%.

5. The method according to claim 1, characterized in that: The hydrogenation catalyst A, based on the weight of the catalyst, has a bulk carbon content of 35-50 wt%, preferably 38-45 wt%; an average pore size of 15-30 nm, preferably 17-25 nm; and a total acid content of 0-0.40 mmol / g, preferably 0.05-0.35 mmol / g.

6. The method according to claim 1, characterized in that: The hydrogenation catalyst A has a surface carbon content of 35-50 wt%, preferably 38-45 wt%, based on the weight of the catalyst; preferably, the difference between the bulk carbon content and the surface carbon content does not exceed 5 wt%, and more preferably does not exceed 3 wt%.

7. The method according to claim 1, characterized in that: The hydrogenation catalyst B comprises a support and a hydrogenation active metal component supported on the support, wherein the support comprises alumina and carbon, and the hydrogenation active metal component comprises a Group VIB metal component and a Group VIII metal component, wherein the Group VIII metal is Ni and / or Co, and the Group VIB metal is W and / or Mo; based on the weight of the catalyst, the content of the Group VIB metal as oxide is 8wt% to 20wt%, and the content of the Group VIII metal as oxide is 1wt% to 9wt%.

8. The method according to claim 1, characterized in that: The hydrogenation catalyst B, based on the weight of the catalyst, has a bulk carbon content of 25-40 wt%, preferably 28-35 wt%; an average pore size of 5-15 nm, preferably 8-13 nm; and a total acid content greater than 0.5 mmol / g, preferably 0.55-0.65 mmol / g.

9. The method according to claim 1, characterized in that: The hydrogenation catalyst B has a surface carbon content of 25-40 wt%, preferably 28-35 wt%, based on the weight of the catalyst; preferably, the difference between the bulk carbon content and the surface carbon content does not exceed 5 wt%, and more preferably does not exceed 3 wt%.

10. The method according to claim 1, characterized in that: Both hydrogenation catalyst A and hydrogenation catalyst B contain an auxiliary agent, which is one or more of P, B, Ti, and Zr; based on the weight of the catalyst, the amount of auxiliary agent added is less than 5 wt% by element.

11. The method according to claim 1, characterized in that: The operating conditions used in the first and second fluidized bed hydrogenation reaction zones are as follows: reaction pressure 10-20 MPa, temperature 400-500℃, and liquid hourly space velocity 0.1-5.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-1000.

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