A method for pre-hydrogenating coal tar raw material

Abstract

The present disclosure relates to a method for pre-hydrogenation of coal tar raw materials, which comprises: S1, centrifugation of the coal tar raw materials to obtain a first solid phase material and a first liquid phase material; S2, filtering the first liquid phase material to obtain a second liquid phase material and a third liquid phase material, wherein the solid content of the second liquid phase material is higher than that of the third liquid phase material; S3, mixing the second liquid phase material with diluent oil and returning to step S1 for centrifugation; S4, contacting the third liquid phase material with a protective catalyst and an asphaltene hydrogenation conversion catalyst under hydrogenation conditions to perform a hydrogenation reaction, and performing gas-liquid separation on the obtained hydrogenation reaction product. The method disclosed in the present disclosure can remove metals and asphaltene in coal tar raw materials, has a high liquid yield, and can more effectively reduce the ash content.

Description

Technical Field

[0001] The present disclosure relates to the field of coal tar processing, and in particular, to a method for pretreating coal tar raw materials. Background Art

[0002] With the rapid development of social economy, my country's demand for petroleum products is also increasing. However, petroleum is a non-renewable energy source and is facing the crisis of depletion. In contrast, China's coal reserves are relatively abundant. Therefore, making liquid fuel from coal has become a basic direction of coal processing and utilization.

[0003] With the rapid development of modern coal chemical industry, the output of coal tar is increasing, and the clean processing and effective utilization of coal tar are becoming more and more important. At present, the main utilization of coal tar is deep processing to extract chemical products or hydrogenation to produce clean fuels. In recent years, the number of fixed-bed coal tar hydrogenation units in China has increased. Among them, fixed-bed hydrogenation units have the characteristics of simple process, small investment, simple operation and high technical maturity. However, when processing coal tar raw materials with high content of metal, ash and asphaltene, it is easy to cause bed blockage, rapid pressure drop, coking blockage of heat exchanger and rapid catalyst deactivation caused by asphaltene deposition on catalyst, etc. The unit is forced to shut down and the start-up time of the unit is shortened, which seriously affects the economic benefits of the enterprise.

[0004] Therefore, in order to extend the operating cycle of the coal tar hydrogenation unit, the coal tar raw materials need to be pretreated to remove metals and ash and realize the hydrogenation conversion of asphaltene, and then carry out fixed-bed hydrogenation to produce clean fuel, which can greatly extend the operating cycle of the unit.

[0005] At present, the pretreatment of coal tar in China mainly adopts centrifugal separation, sedimentation separation, solvent extraction, electric field purification and filtration separation. These methods have the disadvantages of poor pretreatment effect, low efficiency and low utilization rate of coal tar resources.

[0006] CN106701157A discloses a method for demetallizing high-temperature coal tar. Although the method uses diluent oil to dilute, adds alcohol substances and uses a demetallization reactor to pre-treat the high-temperature coal tar to remove metals, water is introduced during the implementation process. The treated water is phenol water, which contains high levels of phenols, ammonia nitrogen, etc., which is difficult to process and does not meet environmental protection requirements.

[0007] CN105713658B discloses a pretreatment process for low-temperature coal tar. The coal tar raw material is pretreated through sedimentation separation, primary electric desalination and secondary electric desalination. The process is complicated and the operation cost is high. In addition, water is introduced during the implementation process, and there is also the problem of difficult treatment of phenol water.

[0008] CN101012385A discloses a method for pretreating coal tar, which utilizes distillate oil and aromatic hydrocarbons to perform two-stage extraction on coal tar to remove ash and asphaltene, etc. Although the solvent extraction separation method has a good purification effect, it uses a large amount of solvent, has a complex process, and has high operating costs. Summary of the invention

[0009] The purpose of the present disclosure is to provide a method for pre-hydrogenation of coal tar raw materials, which can remove metals and asphaltene in the coal tar raw materials and more effectively reduce the ash content.

[0010] In order to achieve the above-mentioned purpose, the present disclosure provides a method for pre-hydrogenation of coal tar feedstock, which comprises: S1, centrifuging the coal tar feedstock to obtain a first solid phase material and a first liquid phase material; S2, filtering the first liquid phase material to obtain a second liquid phase material and a third liquid phase material, wherein the solid content of the second liquid phase material is higher than the solid content of the third liquid phase material; S3, mixing the second liquid phase material with diluent oil and returning to step S1 for the centrifugal separation; S4, contacting the third liquid phase material with a protective catalyst and an asphaltene hydrogenation conversion catalyst under hydrogenation conditions to carry out a hydrogenation reaction, and performing gas-liquid separation on the obtained hydrogenation reaction product.

[0011] Optionally, in step S3, the volume ratio of the diluent oil to the second liquid phase material is (0.05-2.0):1, preferably (0.1-1.5):1.

[0012] Optionally, in step S4, the conditions of the hydrogenation reaction include: hydrogen partial pressure of 4-20 MPa, reaction temperature of 280-380°C, hydrogen to oil volume ratio of 300-1200 Nm 3 / m 3 The volumetric space velocity of the raw material liquid is 0.2-3.0h -1 ;

[0013] Preferably, the hydrogen partial pressure is 6-10 MPa, the reaction temperature is 300-360°C, and the hydrogen-to-oil volume ratio is 500-1000 Nm 3 / m 3 The raw material liquid volume space velocity is 0.5-1.5h -1 .

[0014] Optionally, in step S4, after the third liquid phase material is contacted with three or four of the protection catalysts for a first reaction, the first reaction product is contacted with three or four asphaltene hydroconversion catalysts for a second reaction to obtain the hydrogenation reaction product;

[0015] Preferably, the protection catalyst comprises a first protection catalyst, a second protection catalyst and a third protection catalyst arranged in sequence from upstream to downstream; the active components in the first protection catalyst, the second protection catalyst and the third protection catalyst are independently selected from one or more of Ni, Mo, Ti and Co;

[0016] Preferably, the asphaltene hydroconversion catalyst comprises a first asphaltene hydroconversion catalyst, a second asphaltene hydroconversion catalyst and a third asphaltene hydroconversion catalyst arranged in sequence from upstream to downstream; the active components in the first asphaltene hydroconversion catalyst, the second asphaltene hydroconversion catalyst and the third asphaltene hydroconversion catalyst are each independently selected from one or more of Ni, Mo, W, Ti and Co;

[0017] Preferably, the most probable pore sizes of the first asphaltene hydroconversion catalyst, the second asphaltene hydroconversion catalyst and the third asphaltene hydroconversion catalyst decrease in sequence;

[0018] More preferably, the most probable pore diameter of the first asphaltene hydroconversion catalyst is 13-15 nm, the most probable pore diameter of the second asphaltene hydroconversion catalyst is 10-12 nm, and the most probable pore diameter of the third asphaltene hydroconversion catalyst is 7-9 nm.

[0019] Optionally, the first protective catalyst has an average diameter of 15-17 mm, a most probable pore diameter of 20-22 nm, and a carrier of silicon oxide or aluminum oxide;

[0020] The second protected catalyst has an average diameter of 9-11 mm and a most probable pore diameter of 18-20 nm. Based on the total weight of the second protected catalyst, it contains 0.05-0.2 wt % of nickel oxide, 0.5-1.0 wt % of molybdenum oxide, and the balance of silicon oxide or aluminum oxide;

[0021] The third protection catalyst has an average diameter of 5.6-6.5 mm and a most probable pore diameter of 16-18 nm. Based on the total weight of the third protection catalyst, it contains 0.1-0.5 wt % of nickel oxide, 0.5-2.5 wt % of molybdenum oxide, and the remainder of silicon oxide or aluminum oxide;

[0022] The first asphaltene hydroconversion catalyst has an average diameter of 2.5-3.5 mm and a most probable pore diameter of 13-15 nm, and contains 0.1-1 wt % of nickel oxide, 1-5.5 wt % of molybdenum oxide, and the balance of silicon oxide or aluminum oxide, based on the total weight of the first asphaltene hydroconversion catalyst;

[0023] The second asphaltene hydroconversion catalyst has an average diameter of 1-1.2 mm and a most probable pore diameter of 10-12 nm. Based on the total weight of the second asphaltene hydroconversion catalyst, it contains 1-3 wt% of nickel oxide, 5-8 wt% of molybdenum oxide, and the balance of silicon oxide or aluminum oxide;

[0024] The third asphaltene hydroconversion catalyst has an average diameter of 1-1.2 mm and a most probable pore size of 7-9 nm. Based on the total weight of the third asphaltene hydroconversion catalyst, it contains 2-8 wt% nickel oxide, 8-20 wt% molybdenum oxide, and the remainder silicon oxide or aluminum oxide.

[0025] Optionally, relative to the total volume of 100 volumes of the third asphaltene hydroconversion catalyst, the amount of the first protection catalyst is 10-20 volumes, the amount of the second protection catalyst is 10-30 volumes, the amount of the third protection catalyst is 10-10 volumes, the amount of the first asphaltene hydroconversion catalyst is 30-50 volumes, and the amount of the second asphaltene hydroconversion catalyst is 30-70 volumes.

[0026] Optionally, in step S1, a centrifugal separation device is used for the centrifugal separation, and the centrifugal separation device is selected from a horizontal screw centrifuge and / or a disc centrifuge; the conditions for the centrifugal separation include: an operating temperature of 50-120°C and a rotation speed of 3000-8000 rpm.

[0027] Optionally, the diluent oil includes one or more of naphtha, kerosene, diesel, tail oil, light oil, phenol oil, wash oil, naphthalene oil and anthracene oil.

[0028] Optionally, the coal tar raw material includes one or more of low-temperature coal tar, medium-low-temperature coal tar, medium-temperature coal tar and high-temperature coal tar, or a mixture of one or more of low-temperature coal tar, medium-low-temperature coal tar, medium-temperature coal tar and high-temperature coal tar with anthracene oil and / or wash oil.

[0029] Optionally, in step S2, a filtering device is used for the filtering, and a filter element of the filtering device is selected from one of a stainless steel sintered wire mesh, a stainless steel sintered powder, a ceramic membrane and a flexible filter cloth.

[0030] Through the above technical solution, the method disclosed in the present invention has the following advantages:

[0031] (1) It can effectively remove metals and asphaltene from coal tar raw materials and more effectively reduce the ash content;

[0032] (2) It has the advantages of low energy consumption, low investment, simple process, simple operation and low operating cost;

[0033] (3) No water is introduced, thus avoiding the environmental pollution caused by the difficulty in treating phenol water and meeting environmental protection requirements.

[0034] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0036] Figure 1 It is a schematic flow diagram of the method for pre-hydrogenation treatment of coal tar feedstock provided in the present disclosure.

[0037] Description of Reference Numerals

[0038] 1. Coal tar raw material 2. First solid-liquid separator 3. First solid phase material

[0039] 4. Second solid-liquid separator 5. Dilution oil 6. Hydrogen

[0040] 7. Pre-hydrogenation reactor 8. Gas-liquid separator 9. Circulating hydrogen compressor

[0041] 10. Pretreatment product tank DETAILED DESCRIPTION

[0042] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0043] The present disclosure provides a method for pre-hydrogenation of tar feedstock, wherein the method comprises: S1, centrifugally separating the coal tar feedstock to obtain a first solid phase material and a first liquid phase material; S2, filtering the first liquid phase material to obtain a second liquid phase material and a third liquid phase material, wherein the solid content of the second liquid phase material is higher than the solid content of the third liquid phase material; S3, mixing the second liquid phase material with diluent oil and returning to step S1 for the centrifugal separation; S4, contacting the third liquid phase material with a protective catalyst and an asphaltene hydrogenation conversion catalyst under hydrogenation conditions to carry out a hydrogenation reaction, and performing gas-liquid separation on the obtained hydrogenation reaction product.

[0044] In a specific embodiment of the present disclosure, in step S3, the volume ratio of the diluent oil to the second liquid phase material is (0.05-2.0):1, preferably (0.1-1.5):1.

[0045] In a specific embodiment of the present disclosure, in step S4, the conditions of the hydrogenation reaction include: hydrogen partial pressure of 4-20 MPa, reaction temperature of 280-380°C, hydrogen-to-oil volume ratio of 300-1200 Nm 3 / m 3 The volumetric space velocity of the raw material liquid is 0.2-3.0h -1 Preferably, the hydrogen partial pressure is 6-10MPa, the reaction temperature is 300-360°C, and the hydrogen-oil volume ratio is 500-1000Nm 3 / m 3 The raw material liquid volume space velocity is 0.5-1.5h -1 .

[0046] In a specific embodiment of the present disclosure, in step S4, the third liquid phase material is contacted with at least two protective catalysts and at least two asphaltene hydroconversion catalysts for hydrogenation reaction. In one embodiment, after the third liquid phase material is contacted with three or four of the protective catalysts for a first reaction, the first reaction product is contacted with three or four asphaltene hydroconversion catalysts for a second reaction to obtain the hydrogenation reaction product. In a preferred embodiment, the protective catalyst includes a first protective catalyst, a second protective catalyst and a third protective catalyst arranged in sequence from upstream to downstream; the active components in the first protective catalyst, the second protective catalyst and the third protective catalyst are independently selected from one or more of Ni, Mo, Ti and Co. More preferably, the asphaltene hydroconversion catalyst includes a first asphaltene hydroconversion catalyst, a second asphaltene hydroconversion catalyst and a third asphaltene hydroconversion catalyst arranged in sequence from upstream to downstream; the active components in the first asphaltene hydroconversion catalyst, the second asphaltene hydroconversion catalyst and the third asphaltene hydroconversion catalyst are independently selected from one or more of Ni, Mo, W, Ti and Co. Further preferably, the most probable pore diameters of the first asphaltene hydroconversion catalyst, the second asphaltene hydroconversion catalyst and the third asphaltene hydroconversion catalyst decrease successively, for example, the most probable pore diameter of the first asphaltene hydroconversion catalyst is 13-15 nm, the most probable pore diameter of the second asphaltene hydroconversion catalyst is 10-12 nm, and the most probable pore diameter of the third asphaltene hydroconversion catalyst is 7-9 nm.

[0047] In a preferred specific embodiment of the present disclosure, the average diameter of the first protection catalyst is 15-17mm, the most probable pore size is 20-22nm, and the carrier is silicon oxide or aluminum oxide; the average diameter of the second protection catalyst is 9-11mm, the most probable pore size is 18-20nm, and the total weight of the second protection catalyst is taken as the benchmark, it contains 0.05-0.2% by weight of nickel oxide, 0.5-1.0% by weight of molybdenum oxide, and the remainder of silicon oxide or aluminum oxide; the average diameter of the third protection catalyst is 5.6-6.5mm, the most probable pore size is 16-18nm, and the total weight of the third protection catalyst is taken as the benchmark, it contains 0.1-0.5% by weight of nickel oxide, 0.5-2.5% by weight of molybdenum oxide, and the remainder of silicon oxide or aluminum oxide. The present disclosure does not specifically limit the shape of the protection catalyst, and it can be a catalyst shape well known to those skilled in the art, for example, it can be a porous cylindrical, honeycomb cylindrical, Raschig ring, etc. In one embodiment, the present disclosure provides that the first protection catalyst is in a porous cylindrical shape, the second protection catalyst is in a honeycomb cylindrical shape, and the third protection catalyst is in a Raschig ring shape.

[0048] In a preferred specific embodiment of the present disclosure, the average diameter of the first asphaltene hydroconversion catalyst is 2.5-3.5 mm, the most probable pore diameter is 13-15 nm, and based on the total weight of the first asphaltene hydroconversion catalyst, it contains 0.1-1 wt% of nickel oxide, 1-5.5 wt% of molybdenum oxide, and the balance is silicon oxide or aluminum oxide; the average diameter of the second asphaltene hydroconversion catalyst is 1-1.2 mm, the most probable pore diameter is 10-12 nm, and based on the total weight of the second asphaltene hydroconversion catalyst, it contains 1-3 wt% of nickel oxide, 5-8 wt% of molybdenum oxide, and the balance is silicon oxide or aluminum oxide; the average diameter of the third asphaltene hydroconversion catalyst is 1-1.2 mm, the most probable pore diameter is 7-9 nm, and based on the total weight of the third asphaltene hydroconversion catalyst, it contains 2-8 wt% of nickel oxide, 8-20 wt% of molybdenum oxide, and the balance is silicon oxide or aluminum oxide. The present disclosure does not impose any specific restrictions on the shape of the asphaltene hydroconversion catalyst, which can be any catalyst shape known to those skilled in the art, such as a honeycomb, Raschig ring, or butterfly shape. In one embodiment, the disclosure provides that the first asphaltene hydroconversion catalyst is in the shape of a Raschig ring, the second asphaltene hydroconversion catalyst is in the shape of a butterfly, and the third asphaltene hydroconversion catalyst is in the shape of a butterfly.

[0049] In a specific embodiment of the present disclosure, relative to the total volume of 100 volumes of the third asphaltene hydroconversion catalyst, the amount of the first protection catalyst is 10-20 volumes, the amount of the second protection catalyst is 10-30 volumes, the amount of the third protection catalyst is 10-10 volumes, the amount of the first asphaltene hydroconversion catalyst is 30-50 volumes, and the amount of the second asphaltene hydroconversion catalyst is 30-70 volumes.

[0050] In a preferred embodiment of the present disclosure, in step S1, a centrifugal separation device is used to perform the centrifugal separation, and the centrifugal separation device is selected from a horizontal screw centrifuge and / or a disc centrifuge; the conditions of the centrifugal separation include: an operating temperature of 50-120°C and a rotation speed of 3000-8000 rpm.

[0051] In a specific embodiment of the present disclosure, the diluent oil may be one or more of a hydrogenated product oil, a cut fraction oil of a coal tar raw material, and the diluent oil. The hydrogenated product oil may be obtained by hydrogenating one or more of a petroleum-based raw material, a coal tar raw material, and a Fischer-Tropsch synthetic oil, for example, may include one or more of naphtha, kerosene, diesel, and tail oil, and the cut fraction oil of the coal tar raw material may include one or more of light oil, phenol oil, wash oil, naphthalene oil, and anthracene oil.

[0052] According to the present disclosure, coal tar is well known to those skilled in the art, and refers to coal tar produced by coal pyrolysis or coal gasification or other processes. The coal tar raw material may include low-temperature coal tar produced in the coal gasification process, or may be one or more of low-temperature coal tar, medium-low-temperature coal tar, medium-temperature coal tar and high-temperature coal tar produced in coal pyrolysis or coking process (including low-temperature pyrolysis, medium-temperature pyrolysis and high-temperature coking process), or a mixture of one or more of low-temperature coal tar, medium-low-temperature coal tar, medium-temperature coal tar and high-temperature coal tar with anthracene oil and / or wash oil.

[0053] According to the present disclosure, the distillation range of the low-temperature coal tar can be 50-450°C; the distillation range of the medium-low temperature coal tar can be 50-550°C; the distillation range of the medium-temperature coal tar can be 50-600°C; and the distillation range of the high-temperature coal tar can be 50-650°C.

[0054] In a specific embodiment of the present disclosure, in step S2, a filtering device is used for the filtering, and the filter element of the filtering device can be selected from one of a stainless steel sintered wire mesh, a stainless steel sintered powder, a ceramic membrane and a flexible filter cloth.

[0055] In a specific embodiment of the present disclosure, in step S3, the mixing conditions include: mixing temperature of 50-160° C., mixing time of 30-160 min; preferably, the mixing temperature is 60-120° C., and the mixing time is 60-120 min.

[0056] like Figure 1 As shown, in a specific embodiment disclosed, the coal tar feedstock is pre-hydrogenated by a method comprising the following steps:

[0057] S1, the coal tar raw material 1 to be pretreated enters the first solid-liquid separator 2, and the solid residue and the liquid are centrifuged to obtain a first solid phase material and a first liquid phase material; the separated first solid phase material 3 can be used as a fuel or a coal gasification raw material for gasification;

[0058] S2, the separated first liquid phase material enters the second solid-liquid separator 4 for further filtration to obtain a second liquid phase material and a third liquid phase material, wherein the solid content of the second liquid phase material is higher than the solid content of the third liquid phase material;

[0059] S3, mixing the second liquid phase material with the diluent oil 5 and returning it to the first solid-liquid separator for further centrifugal separation;

[0060] S4. The third liquid phase material is mixed with the hydrogen-containing gas and then enters the pre-hydrogenation reactor 7 to contact with the protective agent and the asphaltene hydrogenation conversion catalyst for hydrogenation reaction; the effluent of the hydrogenation reactor enters the gas-liquid separator 8 for gas-liquid separation, the separated gas stream is pressurized by the circulating hydrogen compressor 9 and mixed with the hydrogen 6 and then returned to the inlet of the pre-hydrogenation reactor 7, the separated liquid stream enters the pretreatment product tank 10, and the pretreatment product can be used as the raw material of the subsequent main hydrogenation unit for further deep hydrogenation.

[0061] The present disclosure is further illustrated below by way of examples, but the present disclosure is not limited thereby.

[0062] In the following examples, unless otherwise specified, all the raw materials used are commercially available. The properties of the coal tar raw materials to be pretreated used below are shown in Table 1.

[0063] In Examples 1-5, along the direction of the reactant flow, the catalysts in the pre-hydrogenation reactor are respectively the first protection catalyst, the second protection catalyst, the third protection catalyst, the first asphaltene hydroconversion catalyst, the second asphaltene hydroconversion catalyst and the third asphaltene hydroconversion catalyst.

[0064] Among them, the first protective catalyst is a porous cylindrical carrier with silicon oxide, a diameter of 15-17 mm, and a maximum pore size of 20-22 nm; the second protective catalyst is a honeycomb cylindrical carrier with a diameter of 9-11 mm and a maximum pore size of 18-20 nm, and its composition is 0.17% by weight of nickel oxide, 0.9% by weight of molybdenum oxide, and the balance is silicon oxide or aluminum oxide; the third protective catalyst is a Raschig ring with a diameter of 5.6-6.5 mm and a maximum pore size of 16-18 nm, and its composition is 0.35% by weight of nickel oxide, 2.0% by weight of molybdenum oxide, and the balance is silicon oxide; the first asphaltene hydroconversion catalyst is Raschig ring The catalyst is annular in shape, with a diameter of 2.5-3.5 mm and a most probable pore size of 13-15 nm, and its composition is 0.8 wt% nickel oxide, 3.0 wt% molybdenum oxide, and the balance is aluminum oxide; the second asphaltene hydroconversion catalyst is butterfly-shaped, with a diameter of 1.0-1.2 mm and a most probable pore size of 10-12 nm, and its composition is 2.2 wt% nickel oxide, 6.5 wt% molybdenum oxide, and the balance is silicon oxide; the third asphaltene hydroconversion catalyst is butterfly-shaped, with a diameter of 1.0-1.2 mm and a most probable pore size of 7-9 nm, and its composition is 5.0 wt% nickel oxide, 17.0 wt% molybdenum oxide, and the balance is silicon oxide.

[0065] Based on the total volume of the third asphaltene hydroconversion catalyst in the pre-hydrogenation reactor, the loading amount of the first protection catalyst is 15 volume %, the loading amount of the second protection catalyst is 20 volume %, the loading amount of the third protection catalyst is 20 volume %, the loading amount of the first asphaltene hydroconversion catalyst is 40 volume %, and the loading amount of the second asphaltene hydroconversion catalyst is 60 volume %.

[0066] Example 1

[0067] S1. The coal tar to be pretreated is used as a raw material, and is first introduced into a first solid-liquid separator to centrifuge solid residue and liquid to obtain a first solid phase material and a first liquid phase material;

[0068] S2, introducing the first liquid phase material into a second solid-liquid separator for filtration to obtain a second liquid phase material and a third liquid phase material; the solid content of the second liquid phase material is higher than the solid content of the third liquid phase material;

[0069] S3, mixing the second liquid phase material separated by the second solid-liquid separator with the hydrogenated tail oil and returning to the first solid-liquid separator for further centrifugal separation of solid residue and liquid, wherein the volume ratio of the hydrogenated tail oil to the liquid stream with high solid content is 0.1:1;

[0070] S4. The third liquid phase material is mixed with hydrogen and then enters a pre-hydrogenation reactor to contact with a protective catalyst and an asphaltene hydrogenation conversion catalyst for a hydrogenation reaction. The effluent of the pre-hydrogenation reactor enters a gas-liquid separator for gas-liquid separation. The separated liquid flow enters a pre-treatment product tank. The pre-treatment product is suitable as a raw material for a subsequent coal tar hydrogenation unit.

[0071] The specific operating conditions of the hydrogenation reactor are shown in Table 2, and the properties of the pretreated coal tar are shown in Table 3.

[0072] Example 2

[0073] S1, using the coal tar to be pretreated as a raw material, first entering a first solid-liquid separator, and centrifuging solid residue and liquid to obtain a first solid phase material and a first liquid phase material;

[0074] S2, introducing the first liquid phase material into a second solid-liquid separator for filtration to obtain a second liquid phase material and a third liquid phase material; the solid content of the second liquid phase material is higher than the solid content of the third liquid phase material;

[0075] S3, the high-solid content liquid stream separated by the second solid-liquid separator is mixed with the wash oil and returned to the first solid-liquid separator for further centrifugal separation of solid residue and liquid, wherein the volume ratio of the wash oil to the high-solid content liquid stream is 0.5:1;

[0076] S4. The third liquid phase material is mixed with hydrogen and then enters the hydrogenation reactor to contact with the protective catalyst and the asphaltene hydrogenation conversion catalyst for hydrogenation reaction. The effluent of the pre-hydrogenation reactor enters the gas-liquid separator for gas-liquid separation. The separated liquid flow enters the pretreatment product tank. The pretreatment product is suitable as a raw material for the subsequent coal tar hydrogenation unit.

[0077] The specific operating conditions of the hydrogenation reactor are shown in Table 2, and the properties of the pretreated coal tar are shown in Table 3.

[0078] Example 3

[0079] S1, using the coal tar to be pretreated as a raw material, first entering a first solid-liquid separator, and centrifuging solid residue and liquid to obtain a first solid phase material and a first liquid phase material;

[0080] S2, introducing the first liquid phase material into a second solid-liquid separator for filtration to obtain a second liquid phase material and a third liquid phase material; the solid content of the second liquid phase material is higher than the solid content of the third liquid phase material;

[0081] S3, mixing the second liquid phase material separated by the second solid-liquid separator with the light oil and returning the mixture to the first solid-liquid separator for further centrifugal separation of solid residue and liquid, wherein the volume ratio of the light oil to the liquid stream with high solid content is 1:1;

[0082] S4. The third liquid phase material is mixed with hydrogen and then enters a pre-hydrogenation reactor to contact with a protective catalyst and an asphaltene hydrogenation conversion catalyst for a hydrogenation reaction. The effluent of the pre-hydrogenation reactor enters a gas-liquid separator for gas-liquid separation. The separated liquid flow enters a pre-treatment product tank. The pre-treatment product is suitable as a raw material for a subsequent coal tar hydrogenation unit.

[0083] The specific operating conditions of the hydrogenation reactor are shown in Table 2, and the properties of the pretreated coal tar are shown in Table 3.

[0084] Example 4

[0085] The coal tar feedstock was pre-hydrogenated in the same manner as in Example 1, except that in step S3, the volume ratio of the hydrogenated tail oil to the second liquid phase material was 0.08:1.

[0086] Example 5

[0087] The coal tar feedstock was pre-hydrogenated in the same manner as in Example 1, except that in step S3, the conditions for the hydrogenation reaction were different, the hydrogen partial pressure was 12 MPa, the reaction temperature was 280 °C, and the hydrogen-to-oil volume ratio was 450 Nm 3 / m 3 The volumetric space velocity of the raw material liquid is 2h -1 .

[0088] Example 6

[0089] The coal tar feedstock is pre-hydrogenated using the same method as in Example 1, except that the catalyst used in step S3 is only the first protective catalyst and the first asphaltene hydroconversion catalyst.

[0090] Comparative Example 1

[0091] The same coal tar to be pretreated as in Example 1 was introduced into a first solid-liquid separator to centrifuge the solid slag and the liquid to obtain a first solid phase material and a first liquid phase material; the first liquid phase material was mixed with hydrogen and then directly introduced into a pre-hydrogenation reactor, and the hydrogen partial pressure was 8.0 MPa, the operating temperature was 330 ° C, and the liquid hourly volume space velocity was 1 h -1 , Hydrogen oil volume ratio is 800Nm 3 / m 3 The product is contacted with the protective catalyst and the asphaltene hydroconversion catalyst under the conditions for hydrogenation reaction. The effluent from the hydrogenation reactor enters the gas-liquid separator for gas-liquid separation. The separated liquid flow enters the pretreatment product tank. The pretreatment product is used as the raw material for the subsequent coal tar hydrogenation unit.

[0092] Table 1

[0093] Coal tar raw materials to be pretreated Hydrogenation tail oil Washing oil Light oil <![CDATA[Density (20 °C) / (g / cm 3 )]]> 1.0400 0.8857 1.0553 0.9371 Ash content / weight% 0.051 0.0036 0.003 0.002 Asphaltene content / % 13.4 Distillation range / ℃ 150～540 320～520 150～200 220～315 Metal content / (μg / g) Fe 61.7 0.5 8.7 0.6 Ni 0.9 ＜0.1 ＜0.1 ＜0.1 V ＜0.1 ＜0.1 ＜0.1 ＜0.1 Na 4.8 0.3 7.2 1.2 Ca 167 ＜0.1 0.2 ＜0.1 Zn 16.6 ＜0.1 ＜0.1 ＜0.1 Al 10.4 1.2 ＜0.1 ＜0.1

[0094] Table 2 Operating conditions

[0095]

[0096]

[0097] Table 3

[0098]

[0099] It can be seen from the above that the method disclosed in the present invention can remove metals and asphaltene in coal tar raw materials and more effectively reduce the ash content.

[0100] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0101] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0102] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for pre-hydrogenating a coal tar feedstock, wherein: The method includes: S1, centrifugally separating the coal tar raw material to obtain a first solid phase material and a first liquid phase material; S2, filtering the first liquid phase material to obtain a second liquid phase material and a third liquid phase material, wherein the solid content of the second liquid phase material is higher than the solid content of the third liquid phase material; Wherein, the filtering is performed by using a filtering device, and the filter element of the filtering device is selected from one of a stainless steel sintered wire mesh, a stainless steel sintered powder, a ceramic membrane and a flexible filter cloth; S3, mixing the second liquid phase material with the diluent oil and returning to step S1 for the centrifugal separation; Wherein, the volume ratio of the diluent oil to the second liquid phase material is (0.05-2.0): 1; The diluent oil is a hydrogenated product oil and / or a cut fraction oil of a coal tar raw material; wherein the hydrogenated product oil is obtained by hydrogenating one or more of a petroleum-based raw material, a coal tar raw material and a Fischer-Tropsch synthetic oil, including one or more of naphtha, kerosene, diesel and tail oil, and the cut fraction oil of the coal tar raw material includes one or more of light oil, phenol oil, wash oil, naphthalene oil and anthracene oil; S4. Under hydrogen conditions, the third liquid phase material is brought into contact with a protective catalyst and an asphaltene hydroconversion catalyst to carry out a hydrogenation reaction, and the obtained hydrogenation reaction product is subjected to gas-liquid separation.

2. The method according to claim 1, wherein: In step S3, the volume ratio of the diluent oil to the second liquid phase material is (0.1-1.5):

1.

3. The method according to claim 1, wherein: In step S4, the conditions of the hydrogenation reaction include: hydrogen partial pressure 4-20MPa, reaction temperature 280-380°C, hydrogen to oil volume ratio 300-1200Nm 3 / m 3 The volumetric space velocity of the raw material liquid is 0.2-3.0h -1 .

4. The method according to claim 3, wherein: In step S4, the conditions of the hydrogenation reaction include: the hydrogen partial pressure is 6-10 MPa, the reaction temperature is 300-360°C, the hydrogen-to-oil volume ratio is 500-1000 Nm 3 / m 3 The raw material liquid volume space velocity is 0.5-1.5h -1 .

5. The method according to claim 1, wherein: In step S4, after the third liquid phase material is contacted with three or four of the protection catalysts for a first reaction, the first reaction product is contacted with three or four asphaltene hydroconversion catalysts for a second reaction to obtain the hydrogenation reaction product.

6. The method according to claim 5, wherein: In step S4, the protection catalyst includes a first protection catalyst, a second protection catalyst and a third protection catalyst arranged in sequence from upstream to downstream; the active components in the first protection catalyst, the second protection catalyst and the third protection catalyst are independently selected from one or more of Ni, Mo, Ti and Co.

7. The method according to claim 6, wherein: In step S4, the asphaltene hydroconversion catalyst includes a first asphaltene hydroconversion catalyst, a second asphaltene hydroconversion catalyst and a third asphaltene hydroconversion catalyst which are arranged in sequence from upstream to downstream; the active components in the first asphaltene hydroconversion catalyst, the second asphaltene hydroconversion catalyst and the third asphaltene hydroconversion catalyst are each independently selected from one or more of Ni, Mo, W, Ti and Co.

8. The method according to claim 7, wherein: In step S4, the most probable pore sizes of the first asphaltene hydroconversion catalyst, the second asphaltene hydroconversion catalyst and the third asphaltene hydroconversion catalyst decrease in sequence.

9. The method according to claim 7, wherein: In step S4, the most probable pore size of the first asphaltene hydroconversion catalyst is 13-15 nm, the most probable pore size of the second asphaltene hydroconversion catalyst is 10-12 nm, and the most probable pore size of the third asphaltene hydroconversion catalyst is 7-9 nm.

10. The method according to claim 7, wherein: The first protective catalyst has an average diameter of 15-17 mm, a maximum pore diameter of 20-22 nm, and a carrier of silicon oxide or aluminum oxide; The second protected catalyst has an average diameter of 9-11 mm and a most probable pore diameter of 18-20 nm. Based on the total weight of the second protected catalyst, it contains 0.05-0.2 wt % of nickel oxide, 0.5-1.0 wt % of molybdenum oxide, and the remainder of silicon oxide or aluminum oxide; The third protection catalyst has an average diameter of 5.6-6.5 mm and a most probable pore diameter of 16-18 nm. Based on the total weight of the third protection catalyst, it contains 0.1-0.5 wt % of nickel oxide, 0.5-2.5 wt % of molybdenum oxide, and the remainder of silicon oxide or aluminum oxide; The first asphaltene hydroconversion catalyst has an average diameter of 2.5-3.5 mm and a most probable pore diameter of 13-15 nm. Based on the total weight of the first asphaltene hydroconversion catalyst, it contains 0.1-1 wt % of nickel oxide, 1-5.5 wt % of molybdenum oxide, and the balance of silicon oxide or aluminum oxide; The second asphaltene hydroconversion catalyst has an average diameter of 1-1.2 mm and a most probable pore diameter of 10-12 nm. Based on the total weight of the second asphaltene hydroconversion catalyst, it contains 1-3 wt % of nickel oxide, 5-8 wt % of molybdenum oxide, and the balance of silicon oxide or aluminum oxide; The third asphaltene hydroconversion catalyst has an average diameter of 1-1.2 mm and a most probable pore size of 7-9 nm. Based on the total weight of the third asphaltene hydroconversion catalyst, it contains 2-8 wt % of nickel oxide, 8-20 wt % of molybdenum oxide, and the remainder of silicon oxide or aluminum oxide.

11. The method according to claim 7, wherein: Relative to the total volume of 100 volumes of the third asphaltene hydroconversion catalyst, the amount of the first protective catalyst is 10-20 volumes, the amount of the second protective catalyst is 10-30 volumes, the amount of the third protective catalyst is 10-10 volumes, the amount of the first asphaltene hydroconversion catalyst is 30-50 volumes, and the amount of the second asphaltene hydroconversion catalyst is 30-70 volumes.

12. The method according to claim 1, wherein: In step S1, the centrifugal separation is performed using a centrifugal separation device, and the centrifugal separation device is selected from a horizontal screw centrifuge and / or a disc centrifuge; The centrifugal separation conditions include: an operating temperature of 50-120° C. and a rotation speed of 3000-8000 rpm.

13. The method according to claim 1, wherein: The coal tar raw material includes one or more of low-temperature coal tar, medium-low-temperature coal tar, medium-temperature coal tar and high-temperature coal tar, or a mixture of one or more of low-temperature coal tar, medium-low-temperature coal tar, medium-temperature coal tar and high-temperature coal tar with anthracene oil and / or washing oil.

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