A method for processing coal liquefied oil

Abstract

The application discloses a processing method of coal liquefied oil products, which comprises the following steps: distillation cutting of coal direct liquefaction crude oil obtained through a coal direct liquefaction process to obtain coal direct liquefaction oil and hydrogenation stable raw oil, distillation cutting of coal indirect liquefaction crude oil obtained through a coal indirect liquefaction process to obtain coal indirect liquefaction oil, and preparation of circulating solvent from the hydrogenation stable raw oil and preparation of military equipment fuel from mixed oil of the coal direct liquefaction oil and the coal indirect liquefaction oil. The method provided by the application is simple in process and easy to operate, the prepared circulating solvent has good hydrogen supply performance, and the yield of the coal direct liquefaction oil can be improved; and the prepared military equipment fuel can be used in military ground vehicle diesel engine equipment and aviation turbine engine equipment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of coal chemical industry, and relates to a processing method of coal liquefaction oil products, in particular to a method for processing and preparing coal direct liquefaction circulating solvent and military equipment fuel by using coal direct liquefaction and coal indirect liquefaction oil products. BACKGROUND

[0002] According to the coal type and resource characteristics in China, coal direct liquefaction and indirect liquefaction are two main development approaches of coal-to-liquids.

[0003] Coal-to-liquids (CTL) is a technology for producing oil products and chemical products by using coal as raw material through a chemical process, which includes two technical routes of coal direct liquefaction and coal indirect liquefaction. Coal direct liquefaction is a process in which coal molecules are broken to produce free radical fragments under high temperature and high pressure and catalysts, and clean liquid fuel and other chemical products are generated under the action of H2 and circulating hydrogen-donor solvent. Coal indirect liquefaction is a process in which coal is gasified into CO and H2, and then converted into hydrocarbon fuel through Fischer-Tropsch synthesis. Compared with conventional oil-based fuel, coal direct liquefaction fuel has the characteristics of high density, high heat capacity, high heat stability, low sulfur and nitrogen, low aromatic hydrocarbon, and super low-temperature flow performance, and coal indirect liquefaction fuel has high cetane number and high net calorific value, and almost no sulfur, nitrogen and aromatic hydrocarbon.

[0004] China has started to research coal direct liquefaction technology since the late 1970s. The Shenhua million-ton direct liquefaction coal-to-liquids demonstration device located in Ordos, Inner Mongolia, has been in stable operation for a long period since it was put into operation in 2010, and has become the first million-ton direct liquefaction coal-to-liquids commercial demonstration device. In the demonstration device, the coal powder obtained through the direct liquefaction reactor is then subjected to a hydrogenation stabilization unit, and the processed heavy product is used as a solvent oil circulating coal slurry, and the light product is subjected to a hydro-upgrading unit to obtain product naphtha and diesel product after desulfurization, denitrification, aromatic saturation and partial cracking, and the product basically retains the molecular structure characteristics of coal. Since the aromatic hydrocarbon content and nitrogen content of the primary coal liquefaction oil obtained from the coal direct liquefaction unit are high, in order to prepare diesel product, on the one hand, hydrogenation desulfurization and aromatic saturation are required, and on the other hand, hydro-upgrading ring opening under harsh hydrogenation conditions is required to improve the cetane number of diesel, the process is long, and the direct liquefaction diesel produced has a low cetane number (about 40), which cannot directly meet the requirements of diesel product, and can only be used as a blending component of vehicle diesel. In addition, the primary coal liquefaction product is first subjected to a hydrogenation stabilization unit, and the processed heavy product is used as a circulating solvent of the direct liquefaction unit, and the light product is subjected to a hydro-upgrading unit, and the hydrogenation of the two parts will inevitably affect the hydrogenation effect of the circulating solvent, thereby affecting the oil yield of the coal liquefaction unit.

[0005] CN201610237828.8 provides a method for preparing coal direct liquefaction circulating solvent by fractionating and grading coal direct liquefaction oil and then mixing after hydrogenation. The preparation method can improve the coal conversion rate and product oil yield of the coal direct liquefaction process, while reducing the loss of part of light oil products and the discharge of residues.

[0006] CN201310452935.9 and CN201310452948.6 provide a method for preparing coal direct liquefaction circulating solvent by hydrogenating the mixture of petroleum refining by-products, coal tar anthracene oil, and coal direct liquefaction oil. This method can significantly improve the hydrogen supply capacity of the circulating solvent, increase the yield of coal direct liquefaction oil, replace part of the high-value gasoline and diesel fractions less than 350°C in the coal direct liquefaction circulating solvent, and improve diesel yield. Moreover, it can alleviate the problem of lightening of the existing circulating solvent and relieve the deposition and coking of materials in the reactor of the coal direct liquefaction process.

[0007] CN103305266B provides a method for preparing various military fuels using coal tar, coal direct liquefaction oil, and kerosene co-refined oil. The obtained raw material oil obtained by distillation cutting of one or more of coal direct liquefaction oil, kerosene co-refined oil, or pretreated coal tar is at least divided into a light fraction and a heavy oil fraction. The light fraction is fed into a hydrofining reactor for hydrofining. The hydrofining oil is cooled, gas-liquid separated, and then fed into a fractionating column for fractionation to obtain military fuels.

[0008] CN102304387A discloses a method for producing coal-based high-density jet fuel. The method introduces a high-density jet fuel that meets the jet fuel standard, which is obtained by separating the light and medium fractions of coal direct liquefaction oil after expansion bed hydroprocessing, and then performing fixed bed deep hydrofining.

[0009] CN108130114A discloses a method for preparing military fuel mainly using petroleum coke as raw material. The military fuel prepared by the method can be used for aviation aircraft or added as a fuel additive to military fuel. The fuel has a C16:1.04 g / cm 3 , which can effectively improve the energy carrying capacity of aircraft, reduce engine fuel consumption, and meet the requirements of long-range, high-speed, and long-range.

[0010] In summary, the coal direct liquefaction fuel is rich in naphthenes, has large specific gravity, high heat capacity, high thermal stability, low sulfur and nitrogen, low aromatic hydrocarbons, and super low-temperature flow performance, and is suitable for preparing large specific gravity jet fuel. However, due to the low content of paraffins, the fuel has low cetane number, and the smoke point and net calorific value indicators are on the edge of the card. The coal indirect liquefaction fuel has high paraffin content, high cetane number, and almost no sulfur, nitrogen and aromatic hydrocarbons. Compared with the coal direct liquefaction fuel, the net calorific value and smoke point of the coal indirect liquefaction fuel are high, but the density and low-temperature flow performance are relatively deviated. Both of them have defects in preparing military single fuel alone.

[0011] In addition, the current coal direct liquefaction industrial demonstration device stabilizes all the coal liquefaction crude oil by hydrogenation to obtain a material, a part of which is processed by hydro-upgrading to produce fuel products, and a part of which is returned to the coal liquefaction unit as a circulating solvent. The circulating solvent is mixed with the hydro-upgrading raw material for processing, and it is impossible to ensure that the hydrogen supply performance of the circulating solvent reaches the optimal effect.

[0012] Therefore, it is necessary to find a processing method that can ensure that the coal direct liquefaction circulating solvent has good hydrogen supply performance and can utilize the advantages of coal direct liquefaction fuel and coal indirect liquefaction fuel to prepare military equipment fuel. SUMMARY

[0013] The purpose of the present application is to provide a processing method of coal liquefaction oil products, which is a processing method for preparing coal direct liquefaction circulating solvent and military equipment fuel suitable for modern military equipment by combined processing of coal direct and indirect liquefaction oil products. The coal direct liquefaction circulating solvent prepared by the method has a hydrogen supply index ≥23mg-Hnβ / g-solvent, and the main indicators of the military equipment fuel can simultaneously meet the technical requirements of GB 6537 "3# jet fuel" and GJB 3075 "military diesel fuel specification", i.e. density (20℃) 775-830kg / m 3 , freezing point ≤-47℃, net calorific value ≥42.8MJ / kg, smoke point ≥25.0mm, thermal stability ≤3.3kPa, lubricity WSD ≤0.65mm, cetane number ≥45, flash point ≥60℃, freezing point ≤-50℃, cold filter plugging point ≤-44℃, and polycyclic aromatic hydrocarbon content ≤7w%.

[0014] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0015] A processing method of coal liquefaction oil products, the method comprising the following steps:

[0016] (1) distillation cutting of coal direct liquefaction crude oil obtained by a coal direct liquefaction process to obtain coal direct liquefaction oil and hydrogenation stabilization raw oil, and distillation cutting of coal indirect liquefaction crude oil obtained by a coal indirect liquefaction process to obtain coal indirect liquefaction oil;

[0017] (2) mixing the hydrogenation-stable raw oil in step (1) with hydrogen gas and then introducing the mixture into a hydrogenation reactor, and performing a hydrogenation stabilization reaction in the hydrogenation reactor with a hydrogenation stabilization catalyst to obtain a circulating solvent to be returned to the coal direct liquefaction unit;

[0018] (3) mixing the coal direct liquefaction oil in step (1) with the coal indirect liquefaction oil to obtain a coal liquefaction mixed oil;

[0019] (4) mixing the coal liquefaction mixed oil obtained in step (3) with hydrogen gas and then introducing the mixture into a hydrofining reactor, and performing a hydrofining reaction in the hydrofining reactor with a hydrofining catalyst to obtain a coal liquefaction hydrogenation product oil;

[0020] (5) subjecting the coal liquefaction hydrogenation product oil obtained in step (4) to fractionation cutting to obtain a naphtha fraction I, a fuel fraction I and a heavy fraction;

[0021] (6) mixing the heavy fraction obtained in step (5) with hydrogen gas and then introducing the mixture into a hydrocracking reactor, and performing a hydrocracking reaction in the hydrocracking reactor with a hydrocracking catalyst to obtain a hydrocracking product oil;

[0022] (7) subjecting the hydrocracking product oil in step (6) to fractionation cutting to obtain a naphtha fraction II and a fuel fraction II;

[0023] (8) mixing the fuel fraction I and the fuel fraction II to obtain a military equipment fuel.

[0024] In the present application, the coal direct liquefaction crude oil is a liquefaction crude oil obtained by a coal direct liquefaction process, for example, obtained by removing oil gas and solid residue from the product oil leaving the coal direct liquefaction reactor, i.e., without further hydrogen treatment, and the distillation range thereof is usually in the range of 30 to 500°C.

[0025] In the present application, the coal direct liquefaction oil and the hydrogenation-stable raw oil are obtained by distillation cutting of the coal direct liquefaction crude oil; in one embodiment, the cutting temperature is 250 to 280°C, such as 255, 260, 265, 270 or 275°C, preferably 250 to 260°C, i.e., the fraction below the cutting temperature is the coal direct liquefaction oil, and the fraction above the cutting temperature is the hydrogenation-stable raw oil.

[0026] In step (2) of the present application, the hydrogenation-stable feedstock is subjected to hydrogenation-stable treatment to obtain a recycle solvent; hydrogenation-stable treatment of coal direct liquefaction oil is well known in the art, and in a preferred embodiment, the hydrogenation-stable reaction conditions are: reaction temperature 360-400°C, preferably 370-390°C, such as 380°C, reaction pressure 10-20 MPa, preferably 12-18 MPa, such as 14, 15 or 16 MPa, hydrogen to oil ratio 500-2000 NL / kg, preferably 800-1500 NL / kg, such as 1000, 1200 or 1400 NL / kg, volume space velocity 0.5-2.0 h -1 preferably 0.8-1.5 h -1 such as 1, 1.2 or 1.4 h -1 .

[0027] In the present application, the coal indirect liquefaction crude oil is a synthetic crude oil obtained by low-temperature Fischer-Tropsch synthesis process (i.e. slurry-bed Fischer-Tropsch synthesis process), for example, which can be obtained by removing oil gas and slag wax from product oil leaving the Fischer-Tropsch reactor, i.e. without further hydrogenation treatment, and the distillation range thereof is generally in the range of 30-500°C.

[0028] In the present application, the coal indirect liquefaction oil is obtained by distillation cutting of coal indirect liquefaction crude oil; in one embodiment, the cutting temperature is 400-450°C, preferably 400-420°C, such as 410°C, i.e. the distillate below this cutting temperature is the coal indirect liquefaction oil.

[0029] In one embodiment, the mass ratio of the coal direct liquefaction oil to the coal indirect liquefaction oil is 30:70-70:30, such as 40:60, 50:50 or 60:40; preferably, the mass ratio of the coal direct liquefaction oil to the coal indirect liquefaction oil is 50:50-60:40, such as 55:45, to improve the quality of the subsequent fuel.

[0030] In step (4) of the present application, the coal liquefaction mixed oil obtained in step (2) is mixed with hydrogen and then introduced into a hydrogenation reactor for hydrofining reaction; wherein the hydrofining reaction is well known in the art, and in one embodiment, the reaction conditions of the hydrofining reaction are: reaction temperature 300-380°C, such as 310, 330, 350 or 370°C, preferably 320-360°C, reaction pressure 8-18 MPa, such as 12, 14 or 16 MPa, preferably 10-15 MPa, hydrogen to oil ratio 300-1500 NL / kg, such as 600, 800 or 1000 NL / kg, preferably 500-1200 NL / kg, volume space velocity 1.0-3.0 h -1 such as 1.2, 1.4, 1.6, 2, 2.3, 2.5 or 2.8 h -1 preferably 1.5-2.5 h -1to improve the quality of the subsequent fuel.

[0031] In step (5) of the present application, when the obtained coal liquefaction hydrogenated product is subjected to fractionation cutting, the cutting temperature of the naphtha fraction I and the fuel fraction I is 120-170°C, such as 130, 140 or 160°C, preferably 150-170°C, i.e. the fraction below the cutting temperature is the naphtha fraction I; the cutting temperature of the fuel fraction I and the heavy oil fraction is 300-320°C, preferably 300-310°C, such as 305°C, i.e. the fraction above the cutting temperature is the heavy oil fraction.

[0032] In step (6) of the present application, the heavy fraction obtained in step (5) is mixed with hydrogen and subjected to hydrocracking treatment; hydrocracking of oil products is well known in the art, and in the preferred embodiment, the hydrocracking reaction conditions are as follows: reaction temperature 300-420°C, such as 320, 350 or 380°C, preferably 340-400°C, reaction pressure 8-18 MPa, such as 12, 14 or 16 MPa, preferably 10-15 MPa, hydrogen to oil ratio 300-2000 NL / kg, such as 400, 600 or 800 NL / kg, preferably 500-1000 NL / kg, volume space velocity 0.5-4.0 h -1 such as 1, 2, 2.5, 3 or 3.5 h -1 , preferably 1.5-2.5 h -1 .

[0033] In step (7) of the present application, the hydrocracking product in step (6) is subjected to fractionation cutting, and preferably, the cutting temperature of the naphtha fraction II and the fuel fraction II is 120-170°C, such as 130, 140 or 160°C, preferably 150-170°C.

[0034] In the present application, the hydrogenation catalysts (including hydrogenation stabilization catalysts, hydrogenation refining catalysts and hydrocracking catalysts) used can be the commonly used supported hydrogenation catalysts in the art, the active components of which can be one or more of Co, Mo, Ni, W metal oxides, the content of the active components accounting for 5-30% by weight of the hydrogenation catalyst, the balance being the carrier; the carrier is selected from one or more of amorphous silicon, amorphous aluminum, amorphous silicon aluminum compounds and porous molecular sieves. The preparation of the supported hydrogenation catalyst is well known in the art, for example, in the present application, taking an alumina carrier as an example, the supported catalyst is prepared by impregnation method, which can be specifically referred to CN100580058C.

[0035] In some embodiments, the active component of the hydrogenation stabilization catalyst is a metal oxide of Mo and Ni, the content of the active metal in the oxidation state >21 wt%, such as 22 wt%-26 wt%; for example, the content of NiO can be 4-5%, the content of MoO3 can be 18-20%.

[0036] In some embodiments, the active component of the hydrofining catalyst is a metal oxide of Mo and Ni, with an oxidized state active metal content of 10-20 wt%, such as 12 wt%, 14 wt%, 16 wt%, or 18 wt%; for example, wherein the MoO3 content can be 9-15%, and the NiO content can be 3-4.5%.

[0037] In some embodiments, the active component of the hydrocracking catalyst is a metal oxide of Ni and W, with an oxidized state active metal content of >21%, such as 23%, 25%, or 28%; for example, wherein the NiO content can be 3-6%, and the WO content can be 20-20.5%.

[0038] In the present application, unless otherwise specified, the percentage or percentage content involved is the mass percentage or mass percentage content.

[0039] Compared with the prior art, the present application has the following advantages:

[0040] (1) The current coal direct liquefaction industrial demonstration device is to perform hydrogenation stabilization on all coal liquefaction crude oil, and part of the obtained material is processed to produce fuel products through hydro-upgrading, and the other part is returned to the coal liquefaction unit as a circulating solvent. The circulating solvent is mixed with the hydro-upgrading raw material for processing, which cannot guarantee that the hydrogen supply performance of the circulating solvent reaches the optimal effect as much as possible. Through the method provided by the present application, the circulating solvent can be processed separately according to the use requirements, so that the circulating solvent has better hydrogen supply performance, promotes the conversion of coal, and improves the yield of coal direct liquefaction oil. Moreover, it is also convenient to adjust the processing conditions of the circulating solvent in real time, and improve the flexibility of operation.

[0041] (2) Compared with coal indirect liquefaction oil, the sulfur, nitrogen and aromatic hydrocarbon content of coal direct liquefaction oil is high, and it does not contain olefins. The olefin and oxygen content of the latter is high, and it almost does not contain sulfur, nitrogen and aromatic hydrocarbons. After mixing, the sulfur, nitrogen, oxygen and other heteroatoms and olefins and aromatic hydrocarbons in the raw material can be diluted through blending, so that the properties of the raw material can be improved. Compared with the hydrogenation of the two, the severity of the hydrofining process can be reduced, and the operation cost can be reduced.

[0042] (3) The current existing coal direct liquefaction oil upgrading process is to first perform hydrogenation stabilization and then perform hydro-upgrading to obtain fuel products. The existing coal indirect liquefaction oil upgrading process is to first perform hydrofining and then perform hydro-deparaffination to obtain fuel products. The process is relatively complex. Through the method provided by the present application, coal direct liquefaction oil and coal indirect liquefaction oil are mixed and directly hydrofined to obtain fuel products, which can simplify the processing flow and reduce the processing cost.

[0043] (4) The coal direct liquefaction fuel is rich in naphthenes, and has the advantages of high density, good thermal stability, and good low-temperature flow performance, but its smoke point and heat value are low, and it cannot meet the use requirements of aviation turbine engines, and its cetane number is only about 40, and it cannot meet the use requirements of military ground diesel engines; the coal indirect liquefaction fuel is rich in paraffins, and has the characteristics of high smoke point and heat value, and high cetane number, but its density is low, and it cannot meet the use requirements. Through the method provided by the present application, the coal direct liquefaction oil and the coal indirect liquefaction oil can be mixed to realize the reasonable optimization of the hydrocarbon composition of the raw materials, improve the hydrocarbon composition architecture of the fuel product, and obtain a military equipment fuel that meets the use requirements of military ground diesel engines and aviation turbine engines.

[0044] The hydrocracking of the hydrocracked heavy oil fraction can crack and isomerize the long-chain paraffins in the indirect liquefaction oil to achieve the purpose of pour point depression, so as to ensure the low-temperature flow performance of the military equipment fuel.

[0045] (5) The method provided by the present application has a simple process, utilizes the complementary advantages of the two process oil properties, shortens the process flow, is easy to operate, and can improve the coal direct liquefaction oil yield due to the good hydrogen supply performance of the prepared circulating solvent; the prepared military equipment fuel can be used on military ground vehicle diesel engine equipment and aviation turbine engine equipment, and the military ground vehicle diesel engine equipment can be used in regions with an environmental temperature of-44 DEG C or above, and the main indicators meet the standard index requirements of the military equipment fuel of GB 6537 "3# jet fuel" and GJB 3075 "military diesel fuel specification". BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 It is a processing flow schematic diagram of the coal liquefaction oil product of the present application.

[0047] Wherein 1 is coal direct liquefaction crude oil, 2 is coal indirect liquefaction crude oil, 3 is coal direct liquefaction oil, 4 is coal indirect liquefaction oil, 5 is a hydrostabilized raw material oil, 6 is a coal direct liquefaction circulating solvent, 7 is a coal liquefaction mixed oil, 8 is a hydrofinished product oil, 9 is a hydrocracking raw material oil, 10 is a hydrocracking product oil, 11 is naphtha, and 12 is a military equipment fuel.

[0048] A is a coal direct liquefaction reactor, B is a coal indirect liquefaction Fischer-Tropsch synthesis reactor, C is a first distillation column, D is a second distillation column, E is a hydrostabilization reactor, F is a static mixer, G is a hydrofining reactor, K is a hydrocracking reactor, H is a first fractionating column, and L is a second fractionating column. DETAILED DESCRIPTION

[0049] The following will be further described in combination with the accompanying drawings Figure 1 The method provided by the present application is further described, but the present application is not limited thereto.

[0050] Direct coal liquefaction fuels are rich in cycloalkanes, possessing characteristics such as high specific gravity, high heat capacity, high thermal stability, low sulfur and nitrogen content, low aromatics content, and excellent low-temperature flow properties. They are suitable for producing high-specific-gravity jet fuels. However, due to their low alkane content, their cetane number is low, and their smoke point and net calorific value are near the limit. Indirect coal liquefaction fuels, on the other hand, have a high alkane content, a high cetane number, and are almost free of sulfur, nitrogen, and aromatics. Comparatively, their net calorific value and smoke point are high, but their density and low-temperature flow properties are relatively inferior. Both methods have drawbacks when used alone to produce military fuels. Furthermore, current direct coal liquefaction industrial demonstration plants hydrogenate and stabilize all the crude coal oil. A portion of the resulting material is then hydrogenated to produce fuel products, while the remainder is returned to the coal liquefaction unit as a circulating solvent. This circulating solvent is mixed with the hydrogenated feedstock for further processing, making it difficult to ensure optimal hydrogen supply performance from the circulating solvent. This invention creatively proposes a processing method for the combined processing of direct and indirect coal liquefaction into petroleum products to prepare direct coal liquefaction circulating solvents and fuels suitable for modern military equipment. The direct coal liquefaction circulating solvents prepared by this method have a hydrogen supply index ≥23mg-Hnβ / g-solvent, and the main indicators of the military equipment fuel can simultaneously meet the technical requirements of GB6537 "3# Jet Fuel" and GJB 3075 "Military Diesel Specification".

[0051] like Figure 1 As shown, the crude coal liquefaction oil 1 obtained from the direct coal liquefaction reactor A is cut into direct coal liquefaction oil 3 and hydrotreated stabilized feedstock oil 5 via the first distillation column C. The crude coal indirect liquefaction oil 2 obtained from the indirect coal liquefaction Fischer-Tropsch synthesis reactor B is cut into indirect coal liquefaction oil 4 via the second distillation column D. The hydrotreated stabilized feedstock oil 5 enters the hydrotreated stabilized reactor E for hydrotreating to produce a direct coal liquefaction circulating solvent 6, which is returned to the direct coal liquefaction reactor A. The direct coal liquefaction oil 3 and the indirect coal liquefaction oil 4 are mixed by the static mixer F, and the resulting coal liquefaction mixed oil 7 enters the hydrotreating refining reactor G. Hydrorefining is performed, and the effluent from the hydrorefining reactor is coal liquefaction hydrorefining product oil 8. This oil enters the first fractionation tower H for cutting to obtain naphtha fraction I, fuel fraction I, and heavy fraction 9. Heavy fraction 9 enters the hydrocracking reactor K for hydrocracking, and the resulting hydrocracking product oil 10 enters the second fractionation tower L. The naphtha fraction II obtained from the second fractionation tower L is mixed with the naphtha fraction I obtained from the first fractionation tower H to obtain naphtha 11. The fuel fraction II obtained from the second fractionation tower L is mixed with the fuel fraction I obtained from the first fractionation tower H to obtain military equipment fuel 12.

[0052] The beneficial effects of the present invention will be further illustrated below with reference to specific embodiments.

[0053] Examples 1-3 and Comparative Example 1

[0054] The same hydrogenation stabilizing catalyst as used in Example 1 and Comparative Example 1, Examples 1-3 are for preparing recycle solvents using hydrogenation stabilized feedstock oil, and Comparative Example 1 is for preparing recycle solvents using coal direct liquefaction crude oil; wherein the feedstock oil properties, process conditions and the properties of the obtained recycle solvents of Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0055] The hydrogenation stabilizing catalyst A used in Example 1 and Comparative Example 1 is an alumina-supported hydrogenation catalyst, and its active components are as follows: NiO content 4.9%, MoO3 content 19.6%.

[0056] The hydrogenation stabilizing catalyst B used in Examples 2 and 3 is an alumina-supported hydrogenation catalyst, and its active components are as follows: NiO content 4.2%, MoO3 content 18.2%.

[0057] As shown in Table 1, compared with Comparative Example 1, the hydrogen supply performance of the recycle solvents obtained in Examples 1-3 is obviously improved.

[0058] Examples 4-7 and Comparative Examples 2-3

[0059] Examples 4-7 are for preparing military equipment fuel using coal liquefaction mixed oil; Comparative Example 2 is for the process and product properties of Shenhua coal direct liquefaction demonstration project, and Comparative Example 3 is for the process and product properties of Shenneng coal indirect liquefaction demonstration project;

[0060] Wherein, the properties of the coal liquefaction oil used are shown in Table 2, the properties of the coal liquefaction mixed oil after mixing the two in a certain ratio are shown in Table 3, and the properties of the military equipment fuel are shown in Table 4.

[0061] Wherein, the catalysts used in each treatment step in Examples 4-7 and Comparative Examples 2-3 are described as follows:

[0062] The hydrofining catalyst C used in Examples 4-5 is an alumina-supported hydrogenation catalyst, and its active components are as follows: MoO3 content 9.5%; NiO content 3.3%;

[0063] The hydrofining catalyst D used in Examples 6-7 is an alumina-supported hydrogenation catalyst, and its active components are as follows: MoO3 content 14.7%; NiO content 4.1%;

[0064] The hydrocracking catalyst E used in Examples 4-5 is an alumina-supported hydrogenation catalyst, and its active components are as follows: NiO content 3.2%; WO content 20.2%; nitrogen content requirement of the hydrocracking feedstock <60 mg / kg.

[0065] The hydrocracking catalyst F used in Examples 6-7 is an alumina-supported hydrogenation catalyst, and its active components are as follows: NiO content 5.4%; WO content 22.2%; nitrogen content requirement of the hydrocracking feedstock <60 mg / kg.

[0066] The hydrogenation modification unit in Comparative Example 2 has a hydrogenation refining catalyst with a MoO3, NiO active metal content of 30%, a hydrogenation modification catalyst with a MoO3, NiO, WO3 active metal content of 31%, and a hydrogenation modification feedstock with a nitrogen content requirement of < 15 mg / kg. The hydrogenation refining catalyst in Comparative Example 3 has a MoO3, NiO active metal content of 20%, a hydrogenation cracking catalyst has a NiO, WO3 active metal content of 28%, and a hydrogenation condensation catalyst has a Ni, W active metal content of 28%.

[0067] As shown in Table 4, the products in Comparative Examples 2 and 3 (i.e., existing engineering processes) must undergo two or more hydrogenation processes, which is complex, long, and costly, and the products cannot directly meet the military equipment fuel index requirements. The coal direct liquefaction product has a non-standard cetane number, smoke point, and net calorific value, and the coal indirect liquefaction product has a non-standard density, freezing point, condensation point, and cold filter point. Examples 4-7 are products obtained using the method described in the present application, and the indexes meet the military equipment fuel use index requirements.

[0068] Compared with Comparative Examples 2-3, the active metal content of the catalysts used in Examples 4-7 is greatly reduced, thereby reducing the catalyst procurement cost, and on the other hand, reducing the nitrogen content requirement of the cracking catalyst feedstock, thereby reducing the severity of the hydrogenation refining in the front stage.

[0069] Table 1 Hydrogenation stable feedstock oil properties, process conditions, and circulating solvent properties

[0070]

[0071]

[0072] Table 2 Coal liquefaction oil properties

[0073]

[0074] Table 3 Coal liquefaction mixed oil properties

[0075]

[0076] Table 4 Military equipment fuel properties and index requirements

[0077]

[0078]

[0079] As shown in Table 4, the product of Comparative Example 2 and Comparative Example 3 (i.e. the prior engineering process) needs to be subjected to two or more hydrogenation processes, the process is complex, the flow is long, the processing cost is high, and the product cannot directly meet the requirements of military single fuel indicators. The cetane number, smoke point and net calorific value of the direct coal liquefaction product do not meet the requirements, and the density, freezing point, condensation point and cold filter point of the indirect coal liquefaction product do not meet the requirements. Examples 4-7 are products obtained by using the method of the present application, and the indicators meet the requirements of military single fuel use indicators.

[0080] In addition, the sulfur, nitrogen and aromatic hydrocarbon content of the fuel fraction I after hydrofining is already low enough to meet the use requirements, the smoke point and net calorific value can also meet the requirements, but the cetane number of the lighter fraction is not ideal. The cetane number of the heavy fraction 9 after hydrofining is high, but the low-temperature flowability is not good, the freezing point and cold filter point cannot meet the requirements. The low-temperature flow performance of the fuel fraction II after hydrocracking is greatly improved, and after mixing with the fuel fraction I after hydrofining, a military single fuel with good low-temperature flow performance, cetane number meeting the use requirements and other indicators meeting the requirements can be obtained.

[0081] As can be seen from the above, on the basis of the successful engineering implementation of the prior direct coal liquefaction and indirect coal liquefaction, the oil upgrading process unit between the two is optimized and coupled, which not only optimizes the product structure, but also reduces the process complexity and improves the overall economic benefit of the coal liquefaction technology, thereby providing beneficial exploration for the large-scale industrial implementation of the coal liquefaction technology.

[0082] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for processing coal liquefaction oil, the method comprising the following steps: (1) The crude oil obtained by direct coal liquefaction process is distilled and cut to obtain direct coal liquefaction oil and hydrogenated stabilized feedstock oil. The crude oil obtained by indirect coal liquefaction process is distilled and cut to obtain indirect coal liquefaction oil. (2) The hydrostabilized feedstock oil from step (1) is mixed with hydrogen and then fed into the hydrotreating reactor. In the hydrotreating reactor, it is contacted with the hydrostabilizing catalyst to carry out the hydrostabilization reaction and obtain a circulating solvent to be returned to the coal direct liquefaction unit. (3) Mix the direct coal liquefaction oil and the indirect coal liquefaction oil in step (1) to obtain coal liquefaction mixed oil; (4) The coal liquefaction mixed oil obtained in step (3) is mixed with hydrogen and then fed into a hydrorefining reactor. In the hydrorefining reactor, it is contacted with a hydrorefining catalyst to carry out a hydrorefining reaction and obtain coal liquefaction hydrogenated oil. (5) The coal liquefaction hydrogenation product obtained in step (4) is fractionated and cut to obtain naphtha fraction I, fuel fraction I and heavy fraction; (6) The heavy fraction obtained in step (5) is mixed with hydrogen and then fed into a hydrocracking reactor. In the hydrocracking reactor, it is contacted with a hydrocracking catalyst to carry out a hydrocracking reaction and obtain hydrocracking product oil. (7) The hydrocracking product oil from step (6) is fractionated to obtain naphtha fraction II and fuel fraction II; (8) Mix fuel fraction I and fuel fraction II to obtain military equipment fuel.

2. The method according to claim 1, characterized in that, The crude oil obtained from direct coal liquefaction is a liquefied crude oil obtained through direct coal liquefaction process, with a distillation range of 30–500°C. The direct coal liquefaction oil and the hydrogenated stabilized feedstock oil are obtained by distillation and cutting of the crude oil obtained from direct coal liquefaction, with a cutting temperature of 250–280°C.

3. The method according to claim 2, characterized in that, The coal direct liquefaction oil and hydrogenated stabilized feedstock oil are obtained by distillation and cutting of coal direct liquefaction crude oil at a cutting temperature of 250-260℃.

4. The method according to claim 2, characterized in that, The mixing mass ratio of direct coal liquefaction oil to indirect coal liquefaction oil is 30:70 to 70:

30.

5. The method according to claim 2, characterized in that, The mixing mass ratio of direct coal liquefaction oil to indirect coal liquefaction oil is 40:60 to 60:

40.

6. The method according to claim 3, characterized in that, The mixing mass ratio of direct coal liquefaction oil to indirect coal liquefaction oil is 50:50-60:

40.

7. The method according to any one of claims 1-6, characterized in that, The crude oil obtained from indirect coal liquefaction is a synthetic crude oil obtained through a low-temperature Fischer-Tropsch synthesis process, with a distillation range of 30–500°C. The crude oil obtained from indirect coal liquefaction is obtained by distillation and cutting of the crude oil at a cutting temperature of 400–450°C.

8. The method according to claim 7, characterized in that, The coal-to-liquids oil is obtained by distillation and cutting of coal-to-liquids crude oil at a cutting temperature of 400–420°C.

9. The method according to claim 7, characterized in that, The hydrogenation stabilization reaction conditions are as follows: reaction temperature 360–400℃, reaction pressure 10–20 MPa, hydrogen-to-oil ratio 500–2000 NL / kg, and volumetric hourly space velocity 0.5–2.0 h⁻¹. -1 .

10. The method according to any one of claims 1-6 and 8-9, characterized in that, The reaction conditions for the hydrogenation refining reaction are: reaction temperature 300–380℃, reaction pressure 8–18 MPa, hydrogen-to-oil ratio 300–1500 NL / kg, and volumetric hourly space velocity 1.0–3.0 h⁻¹. -1 .

11. The method according to any one of claims 1-6 and 8-9, characterized in that, In step (5), when the obtained coal liquefaction hydrogenation product oil is fractionated, the cutting temperature between naphtha fraction I and fuel fraction I is 120-170℃; the cutting temperature between fuel fraction I and heavy oil fraction is 300-320℃.

12. The method according to claim 10, characterized in that, In step (5), when the obtained coal liquefaction hydrogenation product oil is fractionated, the cutting temperature between naphtha fraction I and fuel fraction I is 150-170℃; the cutting temperature between fuel fraction I and heavy oil fraction is 300-310℃.

13. The method according to any one of claims 1-6, 8-9 and 12, characterized in that, The hydrocracking reaction conditions are as follows: reaction temperature 300–420℃, reaction pressure 8–18 MPa, hydrogen-to-oil ratio 300–2000 NL / kg, and volume hourly space velocity 0.5–4.0 h⁻¹. -1 .

14. The method according to any one of claims 1-6, 8-9 and 12, characterized in that, In step (7), when the hydrocracking product oil is fractionated and cut, the cutting temperature between naphtha fraction II and fuel fraction II is 120-170°C.

15. The method according to claim 13, characterized in that, In step (7), when the hydrocracking product oil is fractionated and cut, the cutting temperature between naphtha fraction II and fuel fraction II is 150-170°C.

16. The method according to any one of claims 1-6, 8-9, 12, and 15, characterized in that, The hydrogenation stabilizing catalyst, hydrogenation refining catalyst, and hydrogenation cracking catalyst are all supported hydrogenation catalysts. Their active components are one or more of Co, Mo, Ni, and W metal oxides. The content of the active components accounts for 5 to 30% of the weight of the hydrogenation catalyst, with the remainder being the support. The carrier is selected from one or more of amorphous silicon, amorphous aluminum, amorphous silica-alumina compounds, and porous molecular sieves.

17. The method according to claim 16, characterized in that, The active components of the hydrogenation stabilizing catalyst are Mo and Ni metal oxides, with an oxidized active metal content >21%. The active component of the hydrorefining catalyst is Mo and Ni metal oxides, with an oxidized active metal content of 10%-20%. The active components of the hydrocracking catalyst are Ni and W metal oxides, with an oxidized active metal content >21%.

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