High-density fuel oil and preparation method thereof

Abstract

The invention discloses high-density fuel oil and a preparation method thereof. Comprising the following steps: carrying out alkylation reaction on medium and low temperature coal tar fractions, cyclohexane, a catalyst and a modifier to obtain alkylated modified coal tar; and hydrofining the alkylated modified coal tar to obtain the high-density fuel oil. Through alkylation modification reaction of medium and low temperature coal tar fractions, the problem of ring growth when coal tar is used as a raw material to synthesize high-density fuel is solved. The preparation method is simple in step, alkylation reaction raw materials are easy to obtain, and the physical and chemical properties of the prepared coal-based mixed fuel are superior to those of a high-density fuel prepared from a single compound. The density value of the high-density fuel oil is larger than 1.092 g / mL, the heat value is larger than 42.8 MJ / L, and the high-density fuel oil can meet the requirement for development of high-performance aircrafts.

Description

Technical Field

[0001] The present application relates to the technical field of coal tar, and in particular to a high-density fuel oil and a preparation method thereof. Background Art

[0002] With the development of modern high technology, new high-performance aircraft such as supersonic aircraft, launch vehicles and supersonic missiles require the fuel used to have higher density and energy density (volume calorific value).

[0003] Coal-based derivative oils include coal direct liquefaction oil, kerosene co-refining oil, coal gasification and coal distillation pyrolysis by-product coal tar and other oil products produced by a series of coal chemical processes with coal as the source. Compared with petroleum-based oils, coal-based derivative oils fully retain the molecular structure characteristics of coal rich in aromatic rings, have their own unique properties such as high content of cycloalkanes and hydrogenated aromatics, have good thermal oxidation stability (can withstand high temperatures of 500°C without decomposition of carbon deposits) and high energy density, and are the preferred fuel for high-performance aircraft. Therefore, the study of coal-based high-energy density fuels is an inevitable trend in the development of future aerospace jet fuels.

[0004] The existing method of preparing high-density fuel from coal tar is to directly hydrogenate the fuel oil in the 180-350°C fraction of coal tar; or to prepare high-density fuel through Fischer-Tropsch synthesis of the coal tar fraction <170°C. This direct hydrogenation or chemical synthesis method has problems such as low raw material utilization, low yield of target high-density fuel, low density and calorific value of the obtained fuel, and at the same time, the full fraction of coal tar has not been fully utilized. Summary of the invention

[0005] In order to solve the above-mentioned deficiencies in the art, the present application aims to provide a high-density fuel oil and a preparation method thereof, and to prepare high-density fuel oil by modifying coal tar based on an alkylation reaction.

[0006] According to one aspect of the present application, there is provided a method for preparing high-density fuel oil, comprising:

[0007] Taking the medium and low temperature coal tar fraction, cyclohexane, a catalyst and a modifier for alkylation reaction to obtain alkylated modified coal tar;

[0008] The alkylation modified coal tar is subjected to hydrogenation refining to obtain the high-density fuel oil.

[0009] According to some embodiments of the present application, the medium and low temperature coal tar fraction is a 170-350° C. fraction segment.

[0010] According to some embodiments of the present application, the catalyst is selected from: one or more of: Hβ, HY, USY, and Al-MCM-41 molecular sieve.

[0011] According to some embodiments of the present application, the modifier is selected from one or more of cyclohexene, methylcyclohexene, ethylcyclohexene, cyclopentene, methylcyclopentene, and ethylcyclopentene.

[0012] According to some embodiments of the present application, the alkylation reaction is carried out under an inert atmosphere;

[0013] According to some embodiments of the present application, the reaction temperature of the alkylation reaction is 140-160° C., and the reaction time is 300-600 min.

[0014] According to some embodiments of the present application, the molar ratio of the low-temperature coal tar fraction to the modifier is 1:(1-5).

[0015] According to some embodiments of the present application, the mass ratio of the low-temperature coal tar fraction to the catalyst is 1:(5-10).

[0016] According to some embodiments of the present application, the reaction temperature of the hydrofining is 150-220°C, the hydrogen pressure is 4-8MPa, and the reaction time is 24-48h;

[0017] According to some embodiments of the present application, the catalyst for hydrofining is selected from a supported catalyst Al 2 O 3 、SiO 2 , Al-MCM-41, HZSM-5, Hβ and HY;

[0018] According to some embodiments of the present application, the supported catalyst supports one or more of copper, nickel, gold, platinum or palladium.

[0019] According to some embodiments of the present application, the products of the alkylation reaction include: 2-cyclohexylphenol, 2-cyclohexyl-5-methylphenol, 2-cyclohexyl-3-methylphenol, 7-cyclohexyl-1-ethylnaphthalene, 7-cyclohexyl-1-methylnaphthalene, 2-cyclohexyl-4-ethyl-1H-indene, and 2-cyclohexyl-4-methyl-1H-indene.

[0020] According to some embodiments of the present application, after the alkylation reaction, the method further comprises: filtering and rotary evaporating the reaction product to obtain alkylated modified coal tar;

[0021] According to some embodiments of the present application, the evaporation temperature of the rotary evaporation is 30-40° C., the absolute pressure is 15-25 kPa, and the evaporation time is 6-8 h.

[0022] According to another aspect of the present application, a high-density fuel oil prepared by the above-mentioned preparation method is also provided, wherein the density value of the high-density fuel oil is greater than 1.092 g / mL and the calorific value is greater than 42.8 MJ / L.

[0023] Compared with the prior art, this application has at least the following beneficial effects:

[0024] The present application provides a method for preparing high-density fuel oil, which overcomes the problem of ring growth in synthesizing high-density fuel using coal tar as raw material by alkylation modification reaction of medium-low temperature coal tar fraction. The preparation method has simple steps, and the raw materials for alkylation reaction are easy to obtain. The physical and chemical properties of the prepared coal-based mixed fuel are better than those of high-density fuel prepared from a single compound.

[0025] The high-density fuel oil of the present application has a density greater than 1.092 g / mL and a calorific value greater than 42.8 MJ / L, which can meet the needs of the development of high-performance aircraft.

[0026] The alkylation modification reaction of the present application can achieve full utilization of coal tar, high reaction conversion rate, high selectivity of target products, and the prepared fuel has high density and calorific value. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a flowchart of the preparation process of an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0028] The technical solution of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0029] It is particularly important to point out that similar substitutions and modifications made to the present application are obvious to those skilled in the art, and they are all deemed to be included in the present application. Relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present application to implement and apply the technology of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments.

[0030] If no specific conditions are specified in this application, the preparation shall be carried out under conventional conditions or the conditions recommended by the manufacturer. The raw materials or excipients used, as well as the reagents or instruments used, for which the manufacturers are not specified, are all conventional products that can be obtained commercially.

[0031] The application is described in detail below.

[0032] The purpose of this application is to overcome the problem of ring growth in synthesizing high-density fuel using coal tar as raw material, and propose a method for preparing high-density fuel oil by modifying coal tar based on alkylation reaction, by distilling coal tar to obtain a medium and low temperature fraction (170-350°C), adding a modifier and a catalyst thereto once for modification reaction, filtering the modified product, purifying the organic phase to obtain modified tar. The modified tar is subjected to hydrofining and deep hydrogenation saturation, and finally separated by a separator to obtain high-density fuel.

[0033] The alkylation reaction method of the present application realizes the maximum utilization of coal tar, has simple preparation steps, and the raw materials for the alkylation reaction are easily available. The physical and chemical properties of the prepared coal-based mixed fuel are superior to those of the high-density fuel prepared from a single compound.

[0034] In some examples of the present application, the method for preparing the high-density fuel oil of the present application includes:

[0035] The low-temperature coal tar fraction and cyclohexane are placed in a tank reactor, a catalyst and a modifier are added, and the reaction is carried out at 140-160° C. for 360-600 min under the protection of an inert atmosphere (nitrogen) to obtain an alkylation modified product. The alkylation modified product is filtered and rotary evaporated to obtain modified coal tar. The modified coal tar is hydrorefined to obtain the high-density fuel oil of the present application.

[0036] The alkylation reaction products include at least 2-cyclohexylphenol, 2-cyclohexyl-5-methylphenol, 2-cyclohexyl-3-methylphenol, 7-cyclohexyl-1-ethylnaphthalene, 7-cyclohexyl-1-methylnaphthalene, 2-cyclohexyl-4-ethyl-1H-indene, 2-cyclohexyl-4-methyl-1H-indene and the like.

[0037] Among them, the reaction formula includes the following:

[0038]

[0039] Wherein, the catalyst is selected from: one or more of Hβ, HY, USY, and Al-MCM-41 molecular sieves.

[0040] The modifier is selected from one or more of cyclohexene, methylcyclohexene, ethylcyclohexene, cyclopentene, methylcyclopentene and ethylcyclopentene.

[0041] The molar ratio of the low temperature coal tar fraction to the modifier is 1:(1-5).

[0042] The mass ratio of low temperature coal tar fraction to catalyst is 1:(5-10).

[0043] The reaction temperature of the hydrofining is 150-220°C, the hydrogen pressure is 4-8MPa, and the reaction time is 24-48h; the catalyst for the hydrofining is selected from the supported catalyst Al 2 O 3 、SiO 2 , Al-MCM-41, HZSM-5, Hβ and HY; the supported catalyst is loaded with one or more of copper, nickel, gold, platinum or palladium.

[0044] The evaporation temperature of rotary evaporation is 30-40°C, the absolute pressure is 15-25 kPa, and the evaporation time is 6-8 h.

[0045] The density value of the high-density fuel oil of the present application is greater than 1.092 g / mL, and the mass calorific value of the high-density fuel is greater than 42.8 MJ / L.

[0046] The technical solution of the present application is further described below in conjunction with specific embodiments.

[0047] Example 1

[0048] Raw material preparation: Take an appropriate amount of medium and low temperature coal tar and distill it in a real boiling point distillation device, and take the 170-350°C coal tar fraction as the modified raw material. The specific properties of the medium and low temperature coal tar used are shown in Table 1;

[0049] Alkylation reaction: Cool the coal tar fraction at 170-350°C to room temperature, add 24 mL of coal tar fraction and 150 mL of cyclohexane into a 500 mL autoclave reactor, and add 4 g of molecular sieve Hβ catalyst, 21 g of cyclohexene as a modifier, and N 2 Under protection, the reaction temperature was controlled at 160°C, 0.5MPa, and the reaction time was 200min. After the reaction was completed, the reaction system was filtered to obtain an organic phase, and the organic phase was rotary evaporated to remove the solvent to obtain modified tar. The properties of the modified tar are shown in Figure 2.

[0050] Hydrofining: The modified tar is introduced into the reactor, and nitrogen is first introduced to exhaust the air in the reactor, and then hydrogen with a pressure of 11MPa is introduced. The catalyst is Ni, and the reaction temperature is raised to 360°C, the reaction pressure is 11MPa, the hydrogen-oil ratio is controlled to be 1200:1, and the reaction time is 6h. Hydrofining reaction is carried out under the conditions of removing S in 1a,6b-dihydrocyclopropyl[1,2-d]benzo[b]thiophene in the form of H,S gas to generate 6,6a-dihydro-1aH-cyclopropyl[1,2-a]indene. The obtained product is condensed in a heat exchanger and passed into a high-pressure reactor. After adding a saturated catalyst bed, the catalyst is Pt-Pd / SiO 2 -Al 2 O 3As described above, nitrogen is first introduced to exhaust the air in the reactor, and then hydrogen with a pressure of 5MPa is introduced. The reaction temperature is 280°C, the hydrogen-oil volume ratio is controlled to be 700:1, and the reaction time is 7h for deep hydrogenation saturation. The product obtained by hydrogenation is passed into a separator for gas-liquid separation. The reaction temperature is 280°C and the pressure is 5MPa. The hydrogen in the gas phase can be recycled, and the liquid phase is a high-density fuel solution.

[0051] The obtained products are bicyclohexane, 1,1':3',1"-tricyclohexane, 1,3,5-tricyclohexylcyclohexane, 3-methyl-1,1'-bicyclohexane, 3-ethyl-1,1'-bicyclohexane, 2-cyclohexyldecahydronaphthalene, 2-cyclohexyl-7-methyldecahydronaphthalene, 2-cyclohexyl-7-ethyldecahydronaphthalene, 2-cyclohexylhydro-1H-indene, 2-cyclohexyl-5-methyloctahydro-1H-indene, 2-cyclohexyl-5-ethyloctahydro-1H-indene, etc., wherein the reaction formula includes the following:

[0052] The specific properties of the obtained product are shown in Table 3.

[0053]

[0054]

[0055] Table 1 Properties of medium and low temperature coal tar of Example 1

[0056] <![CDATA[Density (20 °C) / g·cm -3 > 1.0921 <![CDATA[Kinematic viscosity (100 °C) / mm 2 ·s -1 > 120.7 Total nitrogen content / % 0.70 Total sulfur content / % 0.30 Total oxygen content / % 8.05 Moisture content / % 2.30 Alkane content / % 22.80 Aromatic content / % 23.00 Gum content / % 31.04 Asphaltene content / % 24.05 Mechanical impurity content / % 2.60

[0057] Table 2 Properties of modified tar of Example 1

[0058] <![CDATA[Density (20 °C) / g·cm -3 > 1.1495 <![CDATA[Kinematic viscosity (100 °C) / mm 2 ·s -1 > 60.3 Total sulfur content / % 0.7 Moisture content / % 1.0 Alkane content / % 15 Aromatic content / % 85

[0059] Table 3 Product properties of Example 1

[0060] <![CDATA[Density (20 °C) / g·cm -3 > ＞1.092 <![CDATA[Kinematic viscosity (-40 °C) / mm 2 ·s -1 > ＜49.7 <![CDATA[Kinematic viscosity (-20 °C) / mm 2 ·s -1 > ＜20.8 <![CDATA[Kinematic viscosity (20 °C) / mm 2 ·s -1 > ＜5.4 Flash point (closed cup)℃ ＞60 Mass calorific value MJ / Kg ＞42.8 Freezing point℃ ＜-66 Aromatics and olefins content% 3.0

[0061] Example 2

[0062] Raw material preparation: same as Example 1.

[0063] Alkylation reaction: Cool the coal tar fraction at 170-350°C to room temperature, add 24 mL of coal tar fraction and 150 mL of cyclohexane into a 500 mL autoclave reactor, and add 4 g of molecular sieve HY catalyst, 21 g of cyclopentene as a modifier, and N 2 Under protection, the reaction temperature was controlled at 150°C, 0.5MPa, and the reaction time was 300min. After the reaction was completed, the reaction system was filtered to obtain an organic phase, and the organic phase was rotary evaporated to remove the solvent to obtain modified tar. The properties of the modified tar are shown in Figure 4.

[0064] Hydrofining: Same as Example 1. The specific properties of the obtained product are shown in Table 5.

[0065] Table 4 Properties of modified tar of Example 2

[0066] <![CDATA[Density (20 °C) / g·cm -3 > 1.0692 <![CDATA[Kinematic viscosity (100 °C) / mm 2 ·s -1 > 59.2 Total sulfur content / % 0.7 Moisture content / % 0.9 Alkane content / % 14.3 Aromatic content / % 85.7

[0067] Table 5 Product properties of Example 2

[0068] <![CDATA[Density (20 °C) / g·cm -3 > 0.982 <![CDATA[Kinematic viscosity (-40 °C) / mm 2 ·s -1 > 47.8 <![CDATA[Kinematic viscosity (-20 °C) / mm 2 ·s -1 > 21.2 <![CDATA[Kinematic viscosity (20 °C) / mm 2 ·s -1 > 5.3 Flash point (closed cup)℃ ＞60 Mass calorific value MJ / Kg 42.6 Freezing point℃ ＜-66 Aromatics and olefins content% 2.8

[0069] Example 3

[0070] Raw material preparation: same as Example 1.

[0071] Alkylation reaction: Cool the coal tar fraction at 170-350°C to room temperature, add 24 mL of coal tar fraction and 150 mL of cyclohexane into a 500 mL autoclave reactor, and add 4 g of molecular sieve Al-MCM-41 catalyst, 21 g of methylcyclohexene as a modifier, and N 2 Under protection, the reaction temperature was controlled at 160°C, 0.5MPa, and the reaction was carried out for 360min. After the reaction was completed, the reaction system was filtered to obtain an organic phase, and the organic phase was rotary evaporated to remove the solvent to obtain modified tar. The properties of the modified tar are shown in Figure 6.

[0072] Hydrofining: Same as Example 1. The specific properties of the obtained product are shown in Table 7.

[0073] Table 6 Properties of modified tar of Example 2

[0074] <![CDATA[Density (20 °C) / g·cm -3 > 1.143 <![CDATA[Kinematic viscosity (100 °C) / mm 2 ·s -1 > 59.2 Total sulfur content / % 0.6 Moisture content / % 1.0 Alkane content / % 16.8 Aromatic content / % 83.2

[0075] Table 7 Product properties of Example 2

[0076] <![CDATA[Density (20 °C) / g·cm -3 > 0.982 <![CDATA[Kinematic viscosity (-40 °C) / mm 2 ·s -1 > 48.4 <![CDATA[Kinematic viscosity (-20 °C) / mm 2 ·s -1 > 22.3 <![CDATA[Kinematic viscosity (20 °C) / mm 2 ·s -1 > 4.9 Flash point (closed cup)℃ ＞60 Mass calorific value MJ / Kg 41.7 Freezing point℃ ＜-66 Aromatics and olefins content% 2.6

[0077] Comparative Example

[0078] Raw material preparation: same as Example 1.

[0079] A high-density fuel prepared directly from the hydrogenation of medium- and low-temperature coal tar.

[0080] The specific properties of the obtained product are: density less than 0.9 g / mL; freezing point is around 0°C.

[0081] The present application proposes a method for preparing high-density fuel by modifying coal tar through alkylation reaction. Coal tar is alkylated by a modifier such as cyclohexene to synthesize a polycyclic fuel containing a rich branched structure, thereby increasing the fuel density and the density and calorific value of the fuel.

[0082] The present invention discloses a method for preparing high-density fuel by modifying coal tar through alkylation reaction, and prepares high-density fuel by using medium-low temperature coal tar, thereby realizing efficient utilization of coal tar. At the same time, the present invention performs hydrogenation treatment on the modified tar, so that unsaturated hydrocarbons are converted into saturated hydrocarbons, thereby increasing the stability of the fuel.

[0083] Through the above preparation method, the density value of the high-density fuel oil of the present application is greater than 1.092 g / mL, and the calorific value is greater than 42.8 MJ / L.

[0084] The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. It should be noted that, for ordinary technicians in this technical field, several improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A method for preparing high-density fuel oil, characterized in that: include: Taking the medium and low temperature coal tar fraction, cyclohexane, a catalyst and a modifier for alkylation reaction to obtain alkylated modified coal tar; The alkylation modified coal tar is subjected to hydrogenation refining to obtain the high-density fuel oil.

2. The method for preparing high-density fuel oil according to claim 1, characterized in that: The medium and low temperature coal tar fraction is a 170-350° C. fraction segment.

3. The method for preparing high-density fuel oil according to claim 1, characterized in that: The catalyst is selected from one or more of Hβ, HY, USY, and Al-MCM-41 molecular sieves.

4. The method for preparing high-density fuel oil according to claim 1, characterized in that: The modifier is selected from one or more of cyclohexene, methylcyclohexene, ethylcyclohexene, cyclopentene, methylcyclopentene and ethylcyclopentene.

5. The method for preparing high-density fuel oil according to claim 1, characterized in that: The alkylation reaction is carried out under an inert atmosphere; The reaction temperature of the alkylation reaction is 140-160° C., and the reaction time is 300-600 min.

6. The method for preparing high-density fuel oil according to claim 1, characterized in that: The molar ratio of the low temperature coal tar fraction to the modifier is 1:(1-5); The mass ratio of the low-temperature coal tar fraction to the catalyst is 1:(5-10).

7. The method for preparing high-density fuel oil according to any one of claims 1 to 6, characterized in that: The reaction temperature of the hydrofining is 150-220°C, the hydrogen pressure is 4-8MPa, and the reaction time is 24-48h; The hydrofining catalyst is selected from one or more of supported catalysts Al2O3, SiO2, Al-MCM-41, HZSM-5, Hβ and HY; The supported catalyst supports one or more of copper, nickel, gold, platinum or palladium.

8. The method for preparing high-density fuel oil according to any one of claims 1 to 6, characterized in that: The products of the alkylation reaction include: 2-cyclohexylphenol, 2-cyclohexyl-5-methylphenol, 2-cyclohexyl-3-methylphenol, 7-cyclohexyl-1-ethylnaphthalene, 7-cyclohexyl-1-methylnaphthalene, 2-cyclohexyl-4-ethyl-1H-indene, and 2-cyclohexyl-4-methyl-1H-indene.

9. The method for preparing high-density fuel oil according to any one of claims 1 to 6, characterized in that: After the alkylation reaction, the method further comprises: filtering and rotary evaporating the reaction product to obtain the alkylated modified coal tar; The evaporation temperature of the rotary evaporation is 30-40° C., the absolute pressure is 15-25 kPa, and the evaporation time is 6-8 hours.

10. A high-density fuel oil prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The high-density fuel oil has a density value greater than 1.092 g / mL and a calorific value greater than 42.8 MJ / L.

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