A method for secondary suspension bed hydrotreating of crude oil

Abstract

The present invention discloses a method for secondary suspended bed hydrogenation treatment of crude oil. Crude oil, hydrogen and catalyst are mixed and then enter into a crude oil suspended bed hydrogenation and upgrading reaction unit for hydrogenation and upgrading; the reaction product of the crude oil suspended bed hydrogenation and upgrading is separated into a first gas product and a first liquid product through gas-liquid separation; the first liquid product and the subsequent second liquid product are mixed and then enter into a fractionation device to obtain naphtha, diesel, wax oil and residual oil; part of the residual oil is discharged from the device, and the remaining residual oil is mixed with circulating hydrogen and then enters into a residual oil suspended bed hydrocracking reaction unit for hydrogenation reaction; the reaction product of the residual oil suspended bed hydrocracking is separated into a second gas product and a second liquid product through gas-liquid separation. The crude oil suspended bed hydrogenation and upgrading process adopted by the method can significantly improve the quality of crude oil and increase the yield of light oil; coupled with the residual oil suspended bed hydrocracking process, the deep conversion and utilization of residual oil can be realized. The overall process has the advantages of short process, low operating cost and strong raw material adaptability.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum processing, and in particular to a method for secondary suspended bed hydrotreating of crude oil. Background Art

[0002] Oil is the "blood of industry" and the main energy and chemical raw material in the world today. The widespread use of oil has promoted the world's energy revolution and the transformation of modern chemical industry. Many countries have abandoned coal and used oil on a large scale, which has greatly increased the proportion of oil in the world's energy consumption structure. It has become the main driving force for the rapid development of industry and economy, and occupies an important position and role in the national economy. PetroChina is facing the problem of lightening a large amount of inferior heavy oil. At the same time, the treatment of residual oil is difficult, which inevitably pollutes the environment.

[0003] The first processing of crude oil in almost all refineries is crude oil distillation (called tap), such as topping distillation and atmospheric and vacuum distillation. The crude oil processing process first divides the crude oil into different straight-run fractions according to the boiling point requirements of different products, and then removes the non-ideal components in these fractions according to the quality standards of the products; or converts them through chemical reactions to generate the required components, and then obtains a series of qualified petroleum products. It must be pointed out that crude oil is subjected to high temperatures during the atmospheric and vacuum distillation process, resulting in deterioration of crude oil quality. For example, secondary colloids and asphaltene will also appear in large quantities, macromolecular compounds such as asphaltene will aggregate, the height and number of flakes will increase, and metals will be enriched in large quantities, causing certain troubles for subsequent processing.

[0004] Residue oil slurry bed hydrocracking is based on the principle that the conversion rate of residue oil in a single pass is usually only 60% to 70%, and there is 20% to 30% of hydrocracking tail oil in the reaction. This type of hydrocracking tail oil has poor properties and is extremely difficult to process.

[0005] Saudi Aramco's technologies include thermal crude oil to chemicals (TC2C) technology and catalytic crude oil to chemicals (CC2C) technology. The relevant patents of the TC2C technology route include US20130248416A1, US20130228495A1, US20160312132A1, CN201380006638.X, CN201780078205.3, CN201880020904.7, etc. It uses integrated hydroprocessing, steam cracking and coking processes to directly process crude oil to produce olefins and aromatic petrochemical products and petroleum coke. This route targets paraffin-based crude oil as the raw material, and uses hydrogenation to increase the steam cracking raw material yield, thereby increasing the ethylene yield. The heavy oil that cannot be converted is produced through the coking process to produce petroleum coke. The relevant patents of CC2C technology route include US2013033165, CN201380015214.X, etc., which use crude oil hydrocracking, steam cracking, and high-severity catalytic cracking to increase the production of low-carbon olefins and aromatics, but still need to be grafted with high-cost traditional processing technologies such as hydrocracking.

[0006] Sinopec has proposed a method for treating residual oil. Relevant patents include CN202011519110.0, CN202210423646.5, etc., including a fixed bed hydrogenation process for residual oil and a boiling bed hydrogenation process for residual oil. This route targets residual oil and removes part of the asphaltene through hydrogenation, inhibits the precipitation and aggregation of asphaltene, and deeply removes residual carbon and denitrifies. However, problems such as a large amount of coke formation will still occur. Summary of the invention

[0007] Based on previous research and existing problems, the present invention proposes a method for secondary suspended bed hydrotreating of crude oil after further research and analysis, which can efficiently achieve crude oil quality improvement and residual oil utilization, significantly improve the light oil yield of crude oil and reduce the asphaltene content, while achieving the lightening of residual oil.

[0008] To achieve the above object, the present invention provides the following technical solution: a method for secondary suspension bed hydrotreating of crude oil, the method steps are as follows:

[0009] S101, crude oil, hydrogen and catalyst are mixed and enter into a crude oil suspension bed hydrogenation upgrading reaction unit for hydrogenation upgrading reaction;

[0010] S102, the hydrogenated product enters the first separation device for gas-liquid separation;

[0011] S103, the first liquid product separated by the first separation device is mixed with the second liquid product of the residue oil suspension bed hydrocracking unit and then enters the fractionation device to obtain naphtha, diesel, wax oil, and residue oil fractions;

[0012] S104, the residual oil fraction distilled from the fractionation device is mixed with hydrogen and then enters the residual oil suspension bed hydrocracking reactor for hydrocracking reaction;

[0013] S105, the residue oil suspension bed hydrocracking product enters the second separation device;

[0014] S106. The second liquid product separated by the second separation device enters the fractionation device, and the residual oil obtained by fractionation is divided into two parts, of which 95-99% of the residual oil enters the residual oil suspension bed hydrocracking reaction unit for hydrocracking, and 1-5% of the residual oil is discharged.

[0015] Preferably, the conditions of the crude oil suspension bed hydrogenation reactor are: the hydrogen partial pressure in the reactor is 4-20 MPa, the reaction temperature is 350-410°C, the liquid hourly volume space velocity is 0.5-2h -1 , the volume ratio of hydrogen to the mixture is 300-1200.

[0016] Preferably, in S101, crude oil, hydrogen and catalyst are mixed and enter from the bottom of the reactor and flow from bottom to top.

[0017] Preferably, the conditions of the residue oil suspension bed hydrogenation reactor in S104 are: the hydrogen partial pressure in the reactor is 4 to 20 MPa, the reaction

[0018] The temperature is 390~440℃, and the liquid hourly volume space velocity is 0.5~2h -1 , the volume ratio of hydrogen to the mixture is 300 to 1500.

[0019] Preferably, the residue oil and hydrogen are mixed and enter from the bottom of the residue oil suspension bed hydrocracking reactor and flow from bottom to top.

[0020] Preferably, the total amount of the catalyst active metal is 50 to 1000 μg / g, and the catalyst preparation steps are:

[0021] Step 1: a molybdenum source, a long-chain fatty acid amide, an organic solvent, and a vulcanizing agent are reacted in one pot to obtain a molybdenum-based precursor mixed solution;

[0022] Step 2: Separate the molybdenum-based precursor mixed solution to obtain an oil-soluble molybdenum-based catalyst.

[0023] Preferably, a molybdenum source, a long-chain fatty acid amide, an organic solvent, and a vulcanizing agent are added to a reaction kettle together, the molar ratio of the molybdenum source, the long-chain fatty acid amide, the organic solvent, and the vulcanizing agent is 1:0.6-1:5-10:4-10, and the mixture is stirred and heated at 85°C-150°C for 6-12h; the obtained mixed solution is cooled and allowed to stand for stratification, and the aqueous phase is removed to obtain an organic solvent-dispersed oil-soluble molybdenum-based catalyst.

[0024] Preferably, the molybdenum source is any one or a combination of molybdenum trioxide, ammonium heptamolybdate, ammonium tetramolybdate, molybdic acid, molybdenum acetylacetonate, and molybdenum hexacarbonyl.

[0025] Preferably, the long-chain fatty acid amide is any one or more of palmitic acid diethanolamide, lauric acid diethanolamide, stearic acid diethanolamide, oleic acid diethanolamide, behenic acid diethanolamide, arachidic acid diethanolamide, nonanoic acid diethanolamide, capric acid diethanolamide, myristic acid diethanolamide, lignoceric acid diethanolamide, ceric acid diethanolamide, melissic acid diethanolamide, lacquer wax acid diethanolamide, dodecenoic acid diethanolamide, eicosatrienoic acid diethanolamide, and erucic acid diethanolamide.

[0026] Preferably, the organic solvent is any one or more of toluene, petroleum ether, xylene, DMF, and n-butanol; the sulfiding agent is at least one or more of ammonium sulfide, sodium sulfide, sodium hydrosulfide, sodium polysulfide, and thioacetamide.

[0027] Compared with the existing technology, the present invention provides a method for secondary suspension bed hydrotreating of crude oil, which has the following beneficial effects:

[0028] The present invention adopts a suspended bed as a reactor for hydrogenation and quality upgrading and residual oil utilization, which can realize the conversion of macromolecular compounds such as colloids and asphaltene and avoid their further polycondensation and cracking, can significantly improve the quality of crude oil, increase the light oil yield, and reduce the content of macromolecular compounds such as asphaltene, and has the advantages of simple process flow, flexible operation, strong raw material adaptability, high conversion rate of non-ideal components, and good product quality; the residual oil suspended bed hydrocracking device does not need to add fresh catalyst, saves resources, and coupled with the residual oil suspended bed hydrocracking process, the deep conversion and utilization of residual oil can be realized. After the crude oil is hydrotreated in the secondary suspended bed, the light oil yield is greater than 98%, and the tailings amount is less than 2%, realizing the short-process low-cost deep hydrogenation conversion of crude oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The figure is a schematic diagram of the process flow of the crude oil secondary suspension bed hydrotreating method proposed in the present invention.

[0030] In the figure: 1. catalyst; 2. hydrogen; 3. crude oil; 4. crude oil suspended bed hydrogenation upgrading reaction unit; 5. crude oil suspended bed hydrogenation upgrading reaction product; 6. first separation device; 7. gas product; 8. liquid product; 9. fractionation device; 10. naphtha; 11. diesel; 12. wax oil; 13. residual oil; 14. residual oil suspended bed hydrocracking reaction unit; 15. residual oil suspended bed hydrocracking reaction product; 16. second separation device; 17. second gas product; 18. second liquid product; 19. residual oil. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0032] As attached Figure 1 As shown, the detailed process of the method proposed in the present invention is described as follows: the catalyst 1 in the first pipeline, the hydrogen 2 in the second pipeline and the crude oil 3 in the third pipeline are mixed and then enter the crude oil suspension bed hydrocracking reaction unit 4 for hydrocracking; the crude oil suspension bed hydrocracking reaction product 5 obtained after hydrocracking is separated into a first gas product 7 and a first liquid product 8 in the first separation device 6; the liquid product 8 separated by the first separation device 6 enters the fractionation device 9 to obtain naphtha 10, diesel 11, wax oil 12, and residual oil 13 fractions in sequence; the residual oil 13 and the circulating hydrogen enter the residual oil suspension bed hydrocracking reaction unit 14; the residual oil suspension bed hydrocracking reaction product 15 obtained by the residual oil suspension bed hydrocracking reaction unit 14 is separated into a second gas product 17 and a second liquid product 18 in the second separation device 16, the first gas product 17 is collected and utilized, and the second liquid product 18 enters the fractionation device 9 for fractionation; the residual oil 19 is discarded.

[0033] The reaction conditions of crude oil suspension bed hydrogenation reaction unit 4 are as follows: hydrogen partial pressure in the reactor is 4-20 MPa, reaction temperature is 350-410°C, liquid hourly volume space velocity is 0.5-2 h -1 , the volume ratio of hydrogen to the mixture is 300-1200.

[0034] The reaction conditions of the residue oil suspension bed hydrocracking reaction unit 14 are as follows: the hydrogen partial pressure in the reactor is 4-20 MPa, the reaction temperature is 390-440°C, the liquid hourly volume space velocity is 0.5-2 h -1 , the volume ratio of hydrogen to the mixture is 300 to 1500.

[0035] The following examples will further illustrate the method provided by the present invention, but are not intended to limit the present invention.

[0036] Example 1

[0037] The preparation method of the crude oil hydrogenation catalyst for treating crude oil according to the present invention is as follows: weigh 30g of molybdenum oxide, add 100ml of water, weigh 30g of oleic acid diethanolamide, 120g of toluene, and 70g of thioacetamide, add them to the above solution in sequence, heat to 145°C, stir and react for 3h. Centrifuge the obtained solution, separate the liquid and take the oil phase, and prepare the oil-soluble molybdenum-based catalyst M1.

[0038] Table 1 Test conditions for crude oil suspension bed hydrogenation

[0039] project Crude oil hydrogenation Catalyst active components Mo Catalyst dosage, ppm 100 Reaction temperature, °C 390 Hydrogen partial pressure, MPa 7.0 <![CDATA[Space velocity, h -1 > 1.0 <![CDATA[Hydrogen / oil volume ratio Nm 3 / m 3 > 500

[0040] Example 2

[0041] Saudi crude oil was used as the raw material for the suspended bed hydrogenation reaction evaluation. The main properties of the raw material are shown in Table 2, and the specific reaction process conditions are shown in Table 1.

[0042] Table 2 Main properties of Saudi crude oil

[0043]

[0044]

[0045] Table 3 Saudi crude oil hydrogenation quality improvement results

[0046] project Numeric <![CDATA[Density (20 °C) / g·cm -3 > 0.8847 Viscosity (20℃) / mpa·s 17.267 S content / wt% 3.04 N content / wt% 0.18 ＜180℃ 16.51 180-350℃ 31.65 350-520℃ 25.13 ＞520℃ 26.71 ＜520℃ 73.29 Asphaltene / wt% 2.19 Hydrogen to Carbon Ratio H / C 1.78

[0047] From the results in Table 3, it can be seen that the Saudi crude oil is upgraded by the suspended bed hydrogenation process adopted by the method of the present invention, and the light oil yield in the upgraded product is increased by 5.92%, the asphaltene conversion rate is 30.70%, the S content is reduced by 14.85%, the hydrogen-carbon ratio is increased, and the density and viscosity are reduced, indicating that this process has a significant quality improvement effect on crude oil.

[0048] The liquid product after the crude oil suspension bed hydro-upgrading was fractionated, and the obtained residual oil fraction was evaluated for suspension bed hydrocracking reaction. The specific reaction conditions are shown in Table 4.

[0049] Table 4 Residue oil suspension bed hydrocracking test conditions

[0050] project Residue Hydrocracking Catalyst active components Mo Catalyst dosage, ppm 50 Reaction temperature, °C 425 Hydrogen partial pressure, MPa 7.0 <![CDATA[Space velocity, h -1 > 1.0 <![CDATA[Hydrogen / oil volume ratio Nm 3 / m 3 > 500

[0051] Table 5 Final product composition and yield of Saudi crude oil after two-stage suspension bed hydrogenation

[0052] Product composition Proportion, wt% gas 2.82 ＜180℃ 18.47 180-350℃ 39.75 350-520℃ 37.66 >520℃(tailings) 1.30 ＜520℃ 98.70

[0053] From the results in Table 5, it can be seen that after the two-stage suspension bed unit of crude oil slurry bed hydro-upgrading and residue oil suspension bed hydro-cracking, the yield of fraction <520℃ can reach 98.70%, of which 2.82% is gas output, realizing the efficient hydrogenation conversion of crude oil.

[0054] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A method for secondary suspension bed hydroprocessing of crude oil, characterized in that: The steps are as follows: S101, crude oil, hydrogen and catalyst are mixed and enter into a crude oil suspension bed hydrogenation upgrading reaction unit for hydrogenation upgrading reaction; S102, the hydrogenated product enters the first separation device for gas-liquid separation; S103, the first liquid product separated by the first separation device is mixed with the second liquid product of the residue oil suspension bed hydrocracking unit and then enters the fractionation device to obtain naphtha, diesel, wax oil, and residue oil fractions; S104, the residual oil fraction distilled from the fractionation device is mixed with hydrogen and then enters the residual oil suspension bed hydrocracking reactor for hydrocracking reaction; S105, the residue oil suspension bed hydrocracking product enters the second separation device; S106, the second liquid product separated by the second separation device enters the fractionation device, and the residual oil obtained by fractionation is divided into two parts, of which 95-99% of the residual oil enters the residual oil suspension bed hydrocracking reaction unit for hydrocracking, and 1-5% of the residual oil is discharged; The conditions of the crude oil suspension bed hydrogenation reactor are: the hydrogen partial pressure in the reactor is 4-20MPa, the reaction temperature is 350-410℃, and the liquid hourly volume space velocity is 0.5-2h -1 , the volume ratio of hydrogen to the mixture is 300 to 1200; The conditions of the residue oil suspension bed hydrogenation reactor are: the hydrogen partial pressure in the reactor is 4-20MPa, the reaction temperature is 390-440℃, and the liquid hourly volume space velocity is 0.5-2h -1 , the volume ratio of hydrogen to the mixture is 300 to 1500.

2. The method for secondary suspension bed hydrotreating of crude oil according to claim 1, characterized in that: In S101, crude oil, hydrogen and catalyst are mixed and enter from the bottom of the reactor and flow from bottom to top.

3. The method for secondary suspension bed hydrotreating of crude oil according to claim 1, characterized in that: After the residue oil and hydrogen are mixed, they enter from the bottom of the residue oil suspension bed hydrocracking reactor and flow from bottom to top.

4. The method for secondary suspension bed hydrotreating of crude oil according to claim 1, characterized in that: The total amount of the catalyst active metal is 50-1000 μg / g, and the catalyst preparation steps are: Step 1: a molybdenum source, a long-chain fatty acid amide, an organic solvent, and a vulcanizing agent are reacted in one pot to obtain a molybdenum-based precursor mixed solution; Step 2: Separate the molybdenum-based precursor mixed solution to obtain an oil-soluble molybdenum-based catalyst.

5. The method for secondary suspension bed hydrotreating of crude oil according to claim 4, characterized in that: In step 1, a molybdenum source, a long-chain fatty acid amide, an organic solvent and a vulcanizing agent are added into a reaction kettle together, wherein the molar ratio of the molybdenum source, the long-chain fatty acid amide, the organic solvent and the vulcanizing agent is 1:0.6-1:5-10:4-10, and the mixture is stirred and heated at 85°C-150°C for 6-12h; the obtained mixed solution is cooled, allowed to stand for stratification, and the aqueous phase is removed to obtain an oil-soluble molybdenum-based catalyst dispersed in an organic solvent.

6. The method for secondary suspension bed hydrotreating of crude oil according to claim 4 or 5, characterized in that: The molybdenum source is any one or a combination of molybdenum trioxide, ammonium heptamolybdate, ammonium tetramolybdate, molybdic acid, molybdenum acetylacetonate, and molybdenum hexacarbonyl.

7. The method for secondary suspension bed hydrotreating of crude oil according to claim 4 or 5, characterized in that: The long-chain fatty acid amide is any one or more of palmitic acid diethanolamide, lauric acid diethanolamide, stearic acid diethanolamide, oleic acid diethanolamide, behenic acid diethanolamide, arachidic acid diethanolamide, nonanoic acid diethanolamide, capric acid diethanolamide, myristic acid diethanolamide, lignoceric acid diethanolamide, ceric acid diethanolamide, melissic acid diethanolamide, lacquer wax acid diethanolamide, dodecenoic acid diethanolamide, eicosatrienoic acid diethanolamide, and erucic acid diethanolamide.

8. The method for secondary suspension bed hydrotreating of crude oil according to claim 7, characterized in that: The organic solvent is any one or more of toluene, petroleum ether, xylene, DMF, and n-butanol; the sulfiding agent is at least one or more of ammonium sulfide, sodium sulfide, sodium hydrosulfide, sodium polysulfide, and thioacetamide.

Images