CN110396427B - Processing technology of full-range coal tar - Google Patents

Abstract

The invention discloses a processing technology of full-range coal tar. The processing technology comprises the steps of firstly, fractionating full-fraction coal tar to obtain coal tar of each level; then, carrying out hydrogenation and separation on the heavy coal tar to obtain a light product and a heavy product, separating the light product, and collecting gas and liquid; hydrogenating the light coal tar and the gas, and collecting hydrogenation products; fractionating heavy products, and collecting wax oil; hydrogenating the medium coal tar, the liquid, the hydrogenation product and the wax oil, and collecting the hydrogenation product; finally, the hydrogenation product is fractionated, the mode is found for the first time to effectively avoid the excessive cracking of the light coal tar and the light product, the light coal tar and the light product are fully converted into a light oil product through hydrogenation, the cracking degree of the heavy coal tar is deepened, the heavy coal tar is converted into the light oil product to the greatest extent, and finally, the hydrogenation product is fractionated, so that high-yield naphtha and diesel oil can be obtained, and the total yield of the naphtha and the diesel oil is more than 90% through tests.

Description

Processing technology of full-range coal tar

Technical Field

The invention belongs to the technical field of coal chemical industry, and particularly relates to a processing technology of full-range coal tar.

Background

Coal tar is a coke oven by-product, a complex mixture of hydrocarbons, containing many rare species with recycling value, and is a valuable resource that is difficult to obtain in petrochemical industry. However, at the same time, it contains a large amount of oxygen-containing compounds, impurities such as sulfur, nitrogen and metals, and organic impurities, for example, 10 μm-sized iron pieces and oxide powder, and high-temperature thermopolymer having a particle size of 0.5. mu.m. These impurities undoubtedly increase the difficulty of coal tar processing and utilization.

Therefore, the utilization process of coal tar is widely studied by researchers, so as to achieve the purpose of fully utilizing the coal tar. Among a plurality of coal tar processing technologies, chinese patent document CN 103215070 a discloses a method for producing diesel oil from coal tar, which comprises feeding the whole fraction of coal tar into a vacuum fractionating tower, and cutting the coal tar into light-component coal tar and heavy-component coal tar; mixing heavy component coal tar and hydrogen, then feeding the mixture into a slurry bed reactor, and carrying out hydrogenation reaction under the action of a slurry bed catalyst; then, mixing the effluent obtained after the reaction in the slurry bed reactor with the light component coal tar, sending the mixture into a fixed bed reactor, and carrying out hydrogenation reaction under the action of a fixed bed catalyst; and finally, carrying out gas-liquid separation on the effluent obtained after the reaction of the fixed bed reactor, and enabling the liquid matter to flow into a fractionating tower for further segmentation to cut out the diesel fraction.

In the technology, the coal tar is sequentially subjected to primary fractionation, slurry bed hydrogenation, fixed bed hydrogenation, gas-liquid separation and secondary fractionation to prepare the diesel oil with the yield of 55.12%, so that the processing and reutilization of the coal tar are realized. Unfortunately, in the technology, the yield of the wax oil reaches 34.23%, and compared with naphtha and diesel oil, the wax oil is limited in application and has more impurities, so that the application is inconvenient. Therefore, how to reduce the yield of wax oil and improve the yield of naphtha and diesel oil in the coal tar processing technology is a technical problem to be solved urgently in the field.

Disclosure of Invention

Therefore, the invention aims to overcome the defects of high wax oil yield and low naphtha and diesel oil yield in the conventional coal tar processing technology, and further provides a full-fraction coal tar processing technology with low wax oil yield and high naphtha and diesel oil yield.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

the processing technology of the full-range coal tar provided by the invention comprises the following steps:

1) performing primary fractionation on the full-fraction coal tar to obtain light coal tar, medium coal tar and heavy coal tar;

2) sequentially carrying out first hydrogenation and first separation on the heavy coal tar to obtain a light product and a heavy product, carrying out second separation on the light product, and collecting gas and liquid;

3) carrying out second hydrogenation on the light coal tar and the gas, and collecting a second hydrogenation product;

4) carrying out second fractionation on the heavy product, and collecting wax oil;

5) carrying out third hydrogenation on the medium coal tar, the liquid, the second hydrogenation product and the wax oil, and collecting a third hydrogenation product;

6) and carrying out third fractionation on the third hydrogenation product, and collecting naphtha and diesel oil.

Further, in the step 1), the pressure of the first fractionation is normal pressure, and the temperature is 250-.

Further, in the step 2), the reaction pressure of the first hydrogenation is 18-25MPa, and the reaction temperature is 380-460 ℃.

Further, in the step 2), the space velocity of the first hydrogenation is 0.1-0.5h^-1The volume ratio of hydrogen to oil is (800-: 1; and/or the presence of a gas in the gas,

the hydrogenation catalyst used in the first hydrogenation is a suspension bed hydrogenation catalyst, and the addition amount of the hydrogenation catalyst used in the first hydrogenation is 0.5-2 wt% based on the total mass of the heavy coal tar. Preferably, the suspension bed hydrogenation catalyst is amorphous iron oxyhydroxide, magnetic iron oxide, alpha-iron oxyhydroxide.

Further, in step 2), the parameters of the first separation are controlled as follows: the temperature is 370 ℃ and 440 ℃, and the pressure is 18-24 Mpa.

Further, in step 2), the parameters of the second separation are controlled as follows: the temperature is 250 ℃ and 350 ℃, and the pressure is 18-24 Mpa.

Further, in the step 3), the reaction pressure of the second hydrogenation is 18-23Mpa, and the reaction temperature is 250-350 ℃.

Further, in the step 3), the space velocity of the second hydrogenation is 0.5-1h^-1The volume ratio of hydrogen to oil is (500-1500): 1; and/or the presence of a gas in the gas,

the hydrogenation catalyst used in the second hydrogenation is a fixed bed hydrogenation catalyst. The fixed bed hydrogenation catalyst consists of a carrier and active ingredients loaded on the carrier, the load capacity of the active ingredients is 5-15 wt%, and the carrier is active carbon, a molecular sieve or alumina; the active component is at least one of nickel oxide, molybdenum oxide and tungsten oxide.

Further, in the step 4), the second fractionation is vacuum distillation, the pressure of the second fractionation is 1-5kpa (a), and the temperature is 300-. And separating the bottom of the reduced pressure distillation tower to obtain a solid residue product.

Further, in the step 5), the reaction pressure of the third hydrogenation is 18-22Mpa, and the reaction temperature is 360-420 ℃.

Further, in the step 5), the space velocity of the third hydrogenation is 0.5-1h^-1The volume ratio of hydrogen to oil is (500-1500): 1;and/or the presence of a gas in the gas,

the hydrogenation catalyst used in the third hydrogenation is a tungsten-nickel-loaded molecular sieve catalyst, and the loading amount is 15-28 wt%.

Further, in the step 5), the pressure of the third fractionation is 0.8-1.2MPa, and the temperature is 300-.

The wax oil is unsaturated wax oil.

Before the third fractionation of the third hydrogenation product, the method also comprises the steps of carrying out gas-liquid separation on the third hydrogenation product, carrying out the first hydrogenation on the separated gas and the heavy coal tar, and carrying out the third fractionation on the separated liquid.

Compared with the prior art, the invention has the following beneficial effects:

1) the processing technology of the full-range coal tar provided by the invention comprises the steps of firstly carrying out primary fractionation on the full-range coal tar to obtain light coal tar, medium coal tar and heavy coal tar; then, sequentially carrying out first hydrogenation and first separation on the heavy coal tar to obtain a light product and a heavy product, carrying out second separation on the light product, and collecting gas and liquid; carrying out second hydrogenation on the light coal tar and the gas, and collecting a second hydrogenation product; carrying out second fractionation on the heavy product, and collecting wax oil; carrying out third hydrogenation on the medium coal tar, the liquid, the second hydrogenation product and the wax oil, and collecting a third hydrogenation product; finally, carrying out third fractionation on the third hydrogenation product, collecting naphtha and diesel oil, finding out that the mode can effectively avoid excessive cracking of light coal tar and light products for the first time, fully converting the light coal tar and the light products into light oil products through second hydrogenation, deepening the cracking degree of heavy coal tar, converting the heavy coal tar into light oil products to the maximum extent, and finally carrying out third fractionation on the third hydrogenation product to obtain high-yield naphtha and diesel oil, wherein the total yield of the naphtha and the diesel oil is more than 90% through tests;

2) the processing technology of the full-range coal tar provided by the invention is carried out by adopting a multi-stage technology combination, and further limits processing raw materials, control parameters, catalysts and the like of each stage, so that the processing raw materials, the control parameters, the catalysts and the like are reasonably matched, the problem of short operation period of a device caused by high solid content of the coal tar is solved, the activity of the catalysts can be fully exerted, the yield of light oil (such as naphtha and diesel oil) is improved, and the product quality is ensured.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow diagram of an apparatus used in a process for processing whole coal tar in an embodiment of the present invention;

the reference numbers are as follows:

1-full cut coal tar fractionating tower; 2-a suspension bed hydrogenation reactor; 3-a product separation unit; 4-a gas-liquid separation device; 5-a fixed bed hydrogenation reactor; 6-reduced pressure distillation tower; 7-a hydrocracking reactor; 8-a gas-liquid separation device; 9-a product fractionation column; 10-recycle gas compressor.

Detailed Description

The technical solutions of the present invention are described clearly and completely below, and it is obvious that the described embodiments are some, not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The embodiment provides a processing technology of full-range coal tar, as shown in fig. 1, comprising the following steps:

1) introducing the full-range coal tar into a full-range coal tar fractionating tower 1, and carrying out first fractionation on the full-range coal tar at the normal pressure and the temperature of 265 ℃ to obtain light coal tar with the distillation range of 60-180 ℃, medium coal tar with the distillation range of 180-230 ℃ and heavy coal tar with the distillation range of 230-800 ℃;

2) introducing the heavy coal tar into a suspension bed hydrogenation reactor 2, and reacting at the reaction pressure of 20Mpa and the reaction temperature of 410 ℃ for 0.3h^-1And 1300: 1, sequentially carrying out first hydrogenation on the heavy coal tar under the volume ratio of hydrogen to oil, wherein a hydrogenation catalyst is powdery amorphous iron oxyhydroxide and the addition amount is 1.5 wt%; and introducing the hydrogenated product into a product separation device 3 for separation, wherein the separation parameters are as follows: obtaining a light product and a heavy product at the temperature of 410 ℃ and the pressure of 20MPa, cooling the light product to 220 ℃, sending the light product into a separation tank 4, and performing second separation, wherein the parameters of the second separation are as follows: collecting hydrogen-rich gas and liquid at 300 deg.C and 22 MPa;

3) introducing the light coal tar and the gas rich in hydrogen into a fixed bed hydrogenation reactor 5, and reacting at the reaction pressure of 20Mpa, the reaction temperature of 260 ℃ and the reaction time of 0.7h^-1And a space velocity of 700: 1, carrying out second hydrogenation on the hydrogen oil in a volume ratio of the hydrogen oil, wherein a hydrogenation catalyst is nickel oxide loaded on a molecular sieve, the load of the hydrogenation catalyst is 10 wt%, and collecting a second hydrogenation product;

4) sending the heavy product into a reduced pressure distillation tower 6 for separation at the temperature of 320 ℃ and the pressure of 3kpa (a) to obtain a side line unsaturated wax oil product and a tower bottom solid residue product;

5) mixing the medium coal tar, the liquid, the unsaturated wax oil product and the second hydrogenation product, then putting the mixture into a hydrocracking reactor 7, and reacting at the reaction pressure of 20Mpa and the reaction temperature of 380 ℃ for 0.7h^-1And a space velocity of 800: 1, carrying out third hydrogenation on the mixture under the volume ratio of hydrogen to oil, wherein the hydrogenation catalyst is a tungsten-nickel-loaded molecular sieve catalyst, the load of the hydrogenation catalyst is 21 wt%, and collecting a third hydrogenation product;

6) and introducing the third hydrogenation product into a gas-liquid separation device 8, separating to obtain gas and liquid, recycling the gas into the suspension bed hydrogenation reactor 2 through a circulating gas compressor 10 for first hydrogenation, introducing the liquid into a product fractionating tower 9, carrying out third fractionation at 1.0Mpa and 320 ℃, and collecting naphtha and diesel oil.

Example 2

The embodiment provides a processing technology of full-range coal tar, which comprises the following steps:

1) introducing the full-range coal tar into a full-range coal tar fractionating tower 1, and carrying out first fractionation on the full-range coal tar at normal pressure and 250 ℃ to obtain light coal tar with the distillation range of 60-180 ℃, medium coal tar with the distillation range of 180-230 ℃ and heavy coal tar with the distillation range of 230-800 ℃;

2) introducing the heavy coal tar into a suspension bed hydrogenation reactor 2, and reacting at 18Mpa and 450 ℃ for 0.1h^-1And a space velocity of 1500: 1, sequentially carrying out first hydrogenation on the heavy coal tar under the volume ratio of hydrogen to oil, wherein a hydrogenation catalyst is powdered magnetic iron oxide, and the addition amount of the hydrogenation catalyst is 2 wt%; and introducing the hydrogenated product into a product separation device 3 for separation, wherein the separation parameters are as follows: the temperature is 370 ℃, and the pressure is 22Mpa, so that light products and heavy products are obtained; and (3) cooling the light product to 200 ℃, and then sending the light product into a separation tank 4 for second separation, wherein the parameters of the second separation are as follows: collecting hydrogen-rich gas and liquid at 350 deg.C and 18 Mpa;

3) introducing the light coal tar and the gas rich in hydrogen into a fixed bed hydrogenation reactor 5, and reacting at 18Mpa at 280 ℃ for 0.5h^-1And a space velocity of 1000: 1, carrying out second hydrogenation on the hydrogenated oil at a hydrogen-oil volume ratio, wherein hydrogenation catalysts are nickel oxide and molybdenum oxide loaded on activated carbon, the loading amount of the hydrogenation catalysts is 5wt%, and collecting a second hydrogenation product;

4) sending the heavy product into a reduced pressure distillation tower 6 for separation at the temperature of 300 ℃ and the pressure of 5kpa (a) to obtain a side line unsaturated wax oil product and a tower bottom solid residue product;

5) mixing the medium coal tar, the liquid, the unsaturated wax oil product and the second hydrogenation product, then putting the mixture into a hydrocracking reactor 7, and reacting at 22Mpa of reaction pressure and 360 ℃ for 1h^-1And a space velocity of 500: 1, carrying out third hydrogenation on the mixture under the volume ratio of hydrogen to oil, wherein the hydrogenation catalyst isThe tungsten-nickel loaded molecular sieve catalyst has the load of 28wt%, and a third hydrogenation product is collected;

6) and introducing the third hydrogenation product into a product fractionating tower 6, carrying out third fractionation at 0.8Mpa and 350 ℃, and collecting naphtha and diesel oil.

Example 3

The embodiment provides a processing technology of full-range coal tar, which comprises the following steps:

1) introducing the full-range coal tar into a full-range coal tar fractionating tower 1, and carrying out first fractionation on the full-range coal tar at normal pressure and 280 ℃ to obtain light coal tar with the distillation range of 60-180 ℃, medium coal tar with the distillation range of 180-230 ℃ and heavy coal tar with the distillation range of 230-800 ℃;

2) introducing the heavy coal tar into a suspension bed hydrogenation reactor 2, and reacting at the reaction pressure of 22Mpa and the reaction temperature of 380 ℃ for 0.5h^-1And a space velocity of 1000: 1, sequentially carrying out first hydrogenation on the heavy coal tar under the volume ratio of hydrogen to oil, wherein the hydrogenation catalyst is powdery alpha-iron oxyhydroxide and the addition amount is 0.5 wt%; and introducing the hydrogenated product into a product separation device 3 for separation, wherein the separation parameters are as follows: the temperature is 440 ℃, and the pressure is 18Mpa, so that light products and heavy products are obtained; and (3) cooling the light product to 240 ℃, and then sending the light product into a separation tank 4 for second separation, wherein the parameters of the second separation are as follows: collecting hydrogen-rich gas and liquid at 250 deg.C and 24 Mpa;

3) introducing the light coal tar and the gas rich in hydrogen into a fixed bed hydrogenation reactor 5, and reacting at 22Mpa at 250 ℃ for 1h^-1And a space velocity of 500: 1, carrying out second hydrogenation on the hydrogenated oil at a hydrogen-oil volume ratio, wherein hydrogenation catalysts are nickel oxide and tungsten oxide loaded on activated carbon, the loading amount of the hydrogenation catalysts is 15 wt%, and collecting a second hydrogenation product;

4) sending the heavy product into a reduced pressure distillation tower 6 for separation at the temperature of 350 ℃ and the pressure of 1kpa (a) to obtain a side line unsaturated wax oil product and a tower bottom solid residue product;

5) the medium coal is cokedMixing oil, liquid, unsaturated wax oil product and the second hydrogenation product, introducing into hydrocracking reactor 7 under 18Mpa at 390 deg.C for 0.5 hr^-1And a space velocity of 1000: 1, carrying out third hydrogenation on the mixture under the volume ratio of hydrogen to oil, wherein the hydrogenation catalyst is a tungsten-nickel-loaded molecular sieve catalyst, the loading amount of the hydrogenation catalyst is 15 wt%, and collecting a third hydrogenation product;

6) and introducing the third hydrogenation product into a product fractionating tower 6, and carrying out third fractionation at 1.2Mpa and 300 ℃ to collect naphtha and diesel oil.

Example 4

The embodiment provides a processing technology of full-range coal tar, which comprises the following steps:

1) introducing the full-range coal tar into a full-range coal tar fractionating tower 1, and carrying out first fractionation on the full-range coal tar at the normal pressure and the temperature of 255 ℃ to obtain light coal tar with the distillation range of 60-180 ℃, medium coal tar with the distillation range of 180-230 ℃ and heavy coal tar with the distillation range of 230-800 ℃;

2) introducing the heavy coal tar into a suspension bed hydrogenation reactor 2, and reacting at a reaction pressure of 19Mpa and a reaction temperature of 400 ℃ for 0.2h^-1And a space velocity of 1000: 1, sequentially carrying out first hydrogenation on the heavy coal tar under the volume ratio of hydrogen to oil, wherein a hydrogenation catalyst is powdery amorphous iron oxyhydroxide and the addition amount is 1.8 wt%; and introducing the hydrogenated product into a product separation device 3 for separation, wherein the separation parameters are as follows: the temperature is 380 ℃, and the pressure is 21MPa, so that light products and heavy products are obtained;

and (3) cooling the light product to 210 ℃, and then sending the light product into a separation tank 4 for second separation, wherein the parameters of the second separation are as follows: collecting hydrogen-rich gas and liquid at 210 deg.C and 21 Mpa;

3) introducing the light coal tar and the gas rich in hydrogen into a fixed bed hydrogenation reactor 5, and reacting at 21Mpa and 260 ℃ for 0.6h^-1And a space velocity of 900: 1, carrying out second hydrogenation on the mixture at a hydrogen-oil volume ratio, wherein the hydrogenation catalyst is tungsten oxide loaded on a molecular sieveThe loading amount is 8wt%, and a second hydrogenation product is collected;

4) sending the heavy product into a reduced pressure distillation tower 6 for separation at 340 ℃ and 2kpa (a) to obtain a side line unsaturated wax oil product and a tower bottom solid residue product;

5) mixing the medium coal tar, the liquid, the unsaturated wax oil product and the second hydrogenation product, then putting the mixture into a hydrocracking reactor 7, and reacting at 19Mpa and 380 ℃ for 0.6h^-1And a space velocity of 900: 1, carrying out third hydrogenation on the mixture under the volume ratio of hydrogen to oil, wherein the hydrogenation catalyst is a tungsten-nickel-loaded molecular sieve catalyst, the loading amount of the hydrogenation catalyst is 18 wt%, and collecting a third hydrogenation product;

6) and introducing the third hydrogenation product into a product fractionating tower 6, and carrying out third fractionation at 1.1Mpa and 330 ℃ to collect naphtha and diesel.

Example 5

The embodiment provides a processing technology of full-range coal tar, which comprises the following steps:

1) introducing the full-range coal tar into a full-range coal tar fractionating tower 1, and carrying out first fractionation on the full-range coal tar at the normal pressure and the temperature of 270 ℃ to obtain light coal tar with the distillation range of 60-180 ℃, medium coal tar with the distillation range of 180-230 ℃ and heavy coal tar with the distillation range of 230-800 ℃;

2) introducing the heavy coal tar into a suspension bed hydrogenation reactor 2, and reacting at 21Mpa and 390 ℃ for 0.4h^-1And 1100: 1, sequentially carrying out first hydrogenation on the heavy coal tar under the volume ratio of hydrogen to oil, wherein the hydrogenation catalyst is powdered magnetic iron oxide, and the addition amount is 0.9 wt%; and introducing the hydrogenated product into a product separation device 3 for separation, wherein the separation parameters are as follows: the temperature is 430 ℃, and the pressure is 19MPa, so that light products and heavy products are obtained;

and (3) cooling the light product to 230 ℃, and then sending the light product into a separation tank 4 for second separation, wherein the parameters of the second separation are as follows: collecting hydrogen-rich gas and liquid at 270 deg.C and 19 MPa;

3) introducing the light coal tar and the gas rich in hydrogen into a fixed bed hydrogenation reactor 5, and reacting at 19Mpa at 270 ℃ for 0.7h^-1And a space velocity of 800: 1, carrying out second hydrogenation on the mixture under the volume ratio of hydrogen to oil, wherein a hydrogenation catalyst is molybdenum oxide loaded on alumina, the loading amount of the hydrogenation catalyst is 12 wt%, and collecting a second hydrogenation product;

4) sending the heavy product into a reduced pressure distillation tower 6 for separation at 340 ℃ and 2kpa (a) to obtain a side line unsaturated wax oil product and a tower bottom solid residue product;

5) mixing the medium coal tar, the liquid, the unsaturated wax oil product and the second hydrogenation product, then putting the mixture into a hydrocracking reactor 7, and reacting at 21Mpa and 370 ℃ for 0.8h^-1And a space velocity of 700: 1, carrying out third hydrogenation on the mixture under the volume ratio of hydrogen to oil, wherein the hydrogenation catalyst is a tungsten-nickel-loaded molecular sieve catalyst, the load of the hydrogenation catalyst is 23 wt%, and collecting a third hydrogenation product;

6) and introducing the third hydrogenation product into a product fractionating tower 6, and carrying out third fractionation at 0.9Mpa and 320 ℃ to collect naphtha and diesel oil.

Example 6

The embodiment provides a processing technology of full-range coal tar, as shown in fig. 1, comprising the following steps:

1) introducing the full-range coal tar into a full-range coal tar fractionating tower 1, and carrying out first fractionation on the full-range coal tar at the normal pressure and the temperature of 380 ℃ to obtain light coal tar with the distillation range of 60-180 ℃, medium coal tar with the distillation range of 180-230 ℃ and heavy coal tar with the distillation range of 230-800 ℃;

2) introducing the heavy coal tar into a suspension bed hydrogenation reactor 2, and reacting at the reaction pressure of 25Mpa and the reaction temperature of 460 ℃ for 0.3h^-1And a space velocity of 800: 1, sequentially carrying out first hydrogenation on the heavy coal tar under the volume ratio of hydrogen to oil, wherein a hydrogenation catalyst is powdery amorphous iron oxyhydroxide and the addition amount is 1.5 wt%; and introducing the hydrogenated product into a product separation device 3 for separation, wherein the separation parameters are as follows: temperature ofObtaining a light product and a heavy product at the temperature of 410 ℃ and the pressure of 24MPa, cooling the light product to 220 ℃, sending the light product into a separation tank 4, and performing second separation, wherein the parameters of the second separation are as follows: collecting hydrogen-rich gas and liquid at 250 deg.C and 24 Mpa;

3) introducing the light coal tar and the gas rich in hydrogen into a fixed bed hydrogenation reactor 5, and reacting at 23Mpa at 350 ℃ for 0.7h^-1And a space velocity of 1500: 1, carrying out second hydrogenation on the hydrogen oil in a volume ratio of the hydrogen oil, wherein a hydrogenation catalyst is nickel oxide loaded on a molecular sieve, the load of the hydrogenation catalyst is 10 wt%, and collecting a second hydrogenation product;

4) sending the heavy product into a reduced pressure distillation tower 6 for separation at the temperature of 400 ℃ and the pressure of 3kpa (a) to obtain a side line unsaturated wax oil product and a tower bottom solid residue product;

5) mixing the medium coal tar, the liquid, the unsaturated wax oil product and the second hydrogenation product, then putting the mixture into a hydrocracking reactor 7, and reacting at 20Mpa and 420 ℃ for 0.7h^-1And a space velocity of 1500: 1, carrying out third hydrogenation on the mixture under the volume ratio of hydrogen to oil, wherein the hydrogenation catalyst is a tungsten-nickel-loaded molecular sieve catalyst, the load of the hydrogenation catalyst is 21 wt%, and collecting a third hydrogenation product;

6) and introducing the third hydrogenation product into a gas-liquid separation device 8, separating to obtain gas and liquid, recycling the gas into the suspension bed hydrogenation reactor 2 through a circulating gas compressor 10 for first hydrogenation, introducing the liquid into a product fractionating tower 9, carrying out third fractionation at 1.0Mpa and 320 ℃, and collecting naphtha and diesel oil.

Comparative example 1

The comparative example provides a processing technology of full-range coal tar, comprising the following steps:

1) introducing the full-range coal tar into a full-range coal tar fractionating tower, and carrying out first fractionation on the full-range coal tar at the normal pressure and the temperature of 265 ℃ to obtain light coal tar with the distillation range of 60-180 ℃, medium coal tar with the distillation range of 180-230 ℃ and heavy coal tar with the distillation range of 230-800 ℃;

2) introducing the heavy coal tar into a suspension bed hydrogenation reactor 2, and reacting at the reaction pressure of 20Mpa and the reaction temperature of 410 ℃ for 0.3h^-1And 1300: 1, sequentially carrying out first hydrogenation on the heavy coal tar under the volume ratio of hydrogen to oil, wherein a hydrogenation catalyst is powdery amorphous iron oxyhydroxide and the addition amount is 1.5 wt%; and introducing the hydrogenated product into a product separation device 3 for separation, wherein the separation parameters are as follows: obtaining a light product and a heavy product at the temperature of 410 ℃ and the pressure of 20MPa, cooling the light product to 220 ℃, sending the light product into a separation tank 4, and performing second separation, wherein the parameters of the second separation are as follows: collecting hydrogen-rich gas and liquid at 300 deg.C and 22 MPa;

3) introducing the light coal tar and the gas rich in hydrogen into a fixed bed hydrogenation reactor 5, and reacting at the reaction pressure of 20Mpa, the reaction temperature of 260 ℃ and the reaction time of 0.7h^-1And a space velocity of 700: 1, carrying out second hydrogenation on the hydrogen oil in a volume ratio of the hydrogen oil, wherein a hydrogenation catalyst is nickel oxide loaded on a molecular sieve, the load of the hydrogenation catalyst is 10 wt%, and collecting a second hydrogenation product;

4) mixing the medium coal tar, the liquid and the second hydrogenation product, introducing into a hydrocracking reactor 7, and reacting at a reaction pressure of 20Mpa and a reaction temperature of 380 deg.C for 0.7h^-1And a space velocity of 800: 1, carrying out third hydrogenation on the mixture under the volume ratio of hydrogen to oil, wherein the hydrogenation catalyst is a tungsten-nickel-loaded molecular sieve catalyst, the load of the hydrogenation catalyst is 21 wt%, and collecting a third hydrogenation product;

5) and introducing the third hydrogenation product into a product fractionating tower 6, carrying out third fractionation at 1.0Mpa and 320 ℃, and collecting naphtha and diesel oil.

Comparative example 2

The comparative example provides a processing technology of full-range coal tar, comprising the following steps:

1) introducing full-range coal tar into a suspension bed hydrogenation reactor 2, and reacting at 18Mpa at 450 deg.C for 0.1h^-1And a space velocity of 1500: 1, sequentially carrying out first hydrogenation on the heavy coal tar under the hydrogen-oil volume ratio ofThe hydrogenation catalyst is powdered magnetic iron oxide, and the addition amount is 2 wt%; and introducing the hydrogenated product into a product separation device 3 for separation, wherein the separation parameters are as follows: the temperature is 370 ℃, and the pressure is 22Mpa, so that light products and heavy products are obtained; and (3) cooling the light product to 200 ℃, and then sending the light product into a separation tank 4 for second separation, wherein the parameters of the second separation are as follows: collecting hydrogen-rich gas and liquid at 350 deg.C and 18 Mpa;

2) introducing the hydrogen-rich gas into a fixed bed hydrogenation reactor 5, and reacting at 18Mpa at 280 deg.C for 0.5h^-1And a space velocity of 1000: 1, carrying out second hydrogenation on the hydrogenated oil at a hydrogen-oil volume ratio, wherein hydrogenation catalysts are nickel oxide and molybdenum oxide loaded on activated carbon, the loading amount of the hydrogenation catalysts is 5wt%, and collecting a second hydrogenation product;

3) sending the heavy product into a reduced pressure distillation tower 6 for separation at the temperature of 300 ℃ and the pressure of 5kpa (a) to obtain a side line unsaturated wax oil product and a tower bottom solid residue product;

4) mixing the liquid, the unsaturated wax oil product and the second hydrogenation product, introducing into a hydrocracking reactor 7 under 22Mpa at 360 deg.C for 1 hr^-1And a space velocity of 500: 1, carrying out third hydrogenation on the mixture under the volume ratio of hydrogen to oil, wherein the hydrogenation catalyst is a tungsten-nickel-loaded molecular sieve catalyst, the loading capacity of the hydrogenation catalyst is 28wt%, and collecting a third hydrogenation product;

5) and introducing the third hydrogenation product into a product fractionating tower 6, carrying out third fractionation at 0.8Mpa and 350 ℃, and collecting naphtha and diesel oil.

Test example 1

The yields of naphtha, diesel and wax collected after the third fractionation in the above examples and comparative examples were measured, and the corresponding measurement results are shown in the following table 1:

TABLE 1 naphtha, diesel and wax oil yields

	Naphtha yield	Yield of diesel oil	Yield of wax oil
				Example 1	26％	69％	0.8％
Example 2	24％	68％	1.2％
				Example 3	25％	67％	1.3％
Example 4	23％	68.5％	1.5％
				Example 5	23.8％	67.5％	1.4％
Example 6	27％	70％	0.5％
				Comparative example 1	10％	40％	25％
Comparative example 2	11％	45％	27％

From table 1, it can be seen that: by adopting the processing technology of the full-range coal tar, the finally obtained naphtha and diesel oil have higher yield and lower wax oil yield, and the coal tar can be effectively processed and utilized.

Test example 2

The product indexes of the naphtha and the diesel collected in the embodiment of the invention are tested, and the corresponding test results are shown in the following tables 2 and 3:

TABLE 2 naphtha production index for inventive examples

Item	Unit of	Quality index	Test method
				Density of	kg/m3(20℃)	700～800	GB/T1884
Distillation range	℃	45～205	GB/T6536
				Sulfur content	mg/kg	≤10	SH/T0689
Nitrogen content	mg/kg	≤20	SH/T0657
				Copper corrosion		≤1	GB/T5096

TABLE 3 product index of diesel oil of the examples of the present invention

As can be seen from tables 2 and 3: the naphtha and diesel oil prepared by the invention has low sulfur content, nitrogen content and copper corrosion and high product index, and the naphtha and diesel oil collected in the comparative example 1 and the comparative example 2 are measured, wherein the sulfur content, the nitrogen content and the copper corrosion are respectively more than 15, 25 and 3.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims (10)

1. A processing technology of full-range coal tar comprises the following steps:

1) performing primary fractionation on the full-fraction coal tar to obtain light coal tar, medium coal tar and heavy coal tar;

2) sequentially carrying out first hydrogenation and first separation on the heavy coal tar to obtain a light product and a heavy product, carrying out second separation on the light product, and collecting gas and liquid;

3) carrying out second hydrogenation on the light coal tar and the gas, and collecting a second hydrogenation product;

4) carrying out second fractionation on the heavy product, and collecting wax oil;

5) carrying out third hydrogenation on the medium coal tar, the liquid, the second hydrogenation product and the wax oil, and collecting a third hydrogenation product;

6) and carrying out third fractionation on the third hydrogenation product, and collecting naphtha and diesel oil.

2. The process as claimed in claim 1, wherein the pressure of the first fractionation in step 1) is normal pressure and the temperature is 250-380 ℃.

3. The process as claimed in claim 1 or 2, wherein in step 2), the reaction pressure of the first hydrogenation is 18-25Mpa, and the reaction temperature is 380-460 ℃.

4. The process according to claim 1 or 2, wherein in step 2), the space velocity of the first hydrogenation is 0.1-0.5h^-1The volume ratio of hydrogen to oil is (800-: 1; and/or the presence of a gas in the gas,

the hydrogenation catalyst used in the first hydrogenation is a suspension bed hydrogenation catalyst, and the addition amount of the hydrogenation catalyst used in the first hydrogenation is 0.5-2 wt% based on the total mass of the heavy coal tar.

5. The process according to claim 1 or 2, wherein in step 2), the parameters of the first separation are controlled as follows: the temperature is 370 and 440 ℃, and the pressure is 18-24 Mpa; and/or the presence of a gas in the gas,

the parameters of the second separation are controlled as follows: the temperature is 250 ℃ and 350 ℃, and the pressure is 18-24 Mpa.

6. The process according to claim 1 or 2, wherein in step 3), the reaction pressure of the second hydrogenation is 18-23Mpa, and the reaction temperature is 250-350 ℃.

7. The process according to claim 1 or 2, wherein in step 3), the space velocity of the second hydrogenation is 0.5-1h^-1The volume ratio of hydrogen to oil is (500-1500): 1; and/or the presence of a gas in the gas,

the hydrogenation catalyst used in the second hydrogenation is a fixed bed hydrogenation catalyst.

8. The process according to claim 1 or 2, wherein in step 4), the pressure of the second fractionation is 1-5kpa and the temperature is 300-.

9. The process as claimed in claim 1 or 2, wherein in step 5), the reaction pressure of the third hydrogenation is 18-22Mpa, and the reaction temperature is 360-420 ℃; and/or the presence of a gas in the gas,

the space velocity of the third hydrogenation is 0.5-1h^-1The volume ratio of hydrogen to oil is (500-1500): 1; and/or the presence of a gas in the gas,

the hydrogenation catalyst used in the third hydrogenation is a tungsten-nickel-loaded molecular sieve catalyst, and the loading amount is 15-28 wt%.

10. The process according to claim 1 or 2, wherein in step 6), the pressure of the third fractionation is 0.8-1.2Mpa and the temperature is 300-350 ℃.

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