Oil product comprehensive utilization refining and chemical industry combined method

Abstract

This invention discloses a combined refining and chemical process for the comprehensive utilization of petroleum products, belonging to the field of petrochemical product preparation technology. This invention optimizes the process flow of the aromatics extraction unit, steam cracking unit, and hydrocracking unit. Aromatics are extracted from atmospheric and vacuum diesel fuels, and the resulting residual diesel fuel is used as feedstock for steam cracking to produce chemical products. The extracted diesel fuel is used as feedstock for hydrocracking to produce refined petroleum products. This invention can significantly improve the yield of trienes and benzenes, and has strong application prospects in the large-scale commercial industrial production of petrochemical products.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical product technology, specifically relating to a method for extracting aromatics from atmospheric diesel (AGO) and vacuum diesel (VGO) to obtain residual diesel for the production of chemical products, and then using the extracted diesel to produce refined oil products. Background Technology

[0002] The petrochemical industry is a chemical industry that uses petroleum as raw material. Crude oil is processed through primary and secondary processing units, undergoing cracking, hydrogenation, reforming, extraction, and separation to produce refined petroleum products such as liquefied petroleum gas, naphtha, gasoline, aviation kerosene, diesel, lubricating oil, and wax oil, all of which meet national standards. The refined petroleum products obtained from crude oil can also be further processed through cracking and separation to obtain basic raw materials such as ethylene, propylene, butene, butadiene, benzene, toluene, xylene, and ethylbenzene. From these basic raw materials, various basic organic raw materials such as methanol, formaldehyde, ethanol, acetaldehyde, acetic acid, isopropanol, acetone, and phenol can be produced.

[0003] Patent application CN201610931849.X discloses a hydrocracking method for producing chemical feedstocks from diesel fractions. This patent includes the following steps: introducing diesel fractions into a hydrocracking reaction zone containing a hydrocracking catalyst for hydrocracking; and separating the reaction products obtained after the hydrocracking reaction to obtain light naphtha, heavy naphtha, and tail oil fractions, wherein the weight content of alkanes in the diesel fractions is 20-50%. The aforementioned method provided by this invention can produce chemical feedstocks from diesel fractions under medium- and low-pressure conditions. The heavy naphtha can be used as a high-aromatic reforming feedstock, and the light naphtha and tail oil can be used as high-quality steam cracking feedstocks. This patent only discloses a method for producing light naphtha and tail oil from diesel fractions using hydrocracking technology; it does not further produce basic feedstocks such as ethylene, propylene, butene, butadiene, benzene, toluene, xylene, and ethylbenzene.

[0004] Patent application CN201611185839.2 discloses a method for extracting and separating aromatics and alkanes from diesel fractions. The method includes feeding the diesel fraction into an extraction tower from the bottom and feeding the extraction solvent into the extraction tower from the top. After liquid phase extraction, the raffinate rich in alkanes is discharged from the top of the extraction tower, and the solvent rich in aromatics is fed into a first vacuum distillation tower from the bottom of the extraction tower for vacuum distillation. The light aromatics with lower boiling points are discharged from the top of the first vacuum distillation tower, and the solvent containing heavy aromatics with higher boiling points is discharged from the bottom of the first vacuum distillation tower and enters the upper part of a back-extraction tower. The back-extraction agent enters the back-extraction tower from the bottom. After back-extraction, the heavy aromatics dissolve in the back-extraction agent to form a back-extraction phase. The solvent-poor phase is discharged from the bottom of the back-extraction tower, and the back-extraction phase is discharged from the top of the back-extraction tower and enters the lower part of a second vacuum distillation tower. The back-extraction agent is discharged from the top of the second vacuum distillation tower and returned to the lower part of the back-extraction tower. The heavy aromatics are discharged from the bottom of the second vacuum distillation tower. This method can improve the recovery rate of aromatics in diesel fractions, increase the purity of extraction solvent recovery, and reduce energy consumption. However, this patent only discloses a method for separating diesel fractions into alkane-rich raffinate, light aromatics, and heavy aromatics using aromatic extraction technology; it does not further disclose the production of basic raw materials such as ethylene, propylene, butene, butadiene, benzene, toluene, xylene, and ethylbenzene.

[0005] Patent application CN202010682905.7 discloses a multi-product apparatus and method for low-carbon olefins and aromatics. This patent includes two riser reactors, two settlers, two fractionation towers, a gasoline hydrodesulfurization unit, a gasoline cut-distillation unit, and an aromatics extraction unit. The first riser reactor, the first settler, the catalytic gasoline outlet of the first fractionation tower, the feed inlet of the second riser reactor, the second settler, the second fractionation tower, the catalytic gasoline outlet of the second fractionation tower, the gasoline hydrodesulfurization unit, the gasoline cut-distillation unit, the gasoline heavy fraction outlet of the gasoline cut-distillation unit, and the aromatics extraction unit are sequentially connected. This multi-product apparatus has a simple structure and utilizes a combined catalytic cracking-aromatics extraction process to process low-quality heavy oil. While producing low-carbon olefins and aromatics, it does not produce low-quality catalytic gasoline and catalytic diesel, thus realizing the transformation of the refining unit into a chemical plant, with significant economic and social benefits. The patent only discloses the apparatus and method for producing more low-carbon olefins and aromatics. A series of process production units, such as catalytic cracking, gasoline hydrodesulfurization, gasoline cutting distillation, and aromatics extraction, are required to realize the transformation of the oil refining unit into a chemical plant. Summary of the Invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a combined refining and chemical method for the comprehensive utilization of oil products, so as to solve the problem of complex process flow without refining and chemical products in the existing technology.

[0007] Technical Solution: To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] A combined refining and chemical process for comprehensive oil product utilization involves setting up an aromatics extraction unit, a steam cracking unit, and a hydrocracking unit to control the increase of chemical products in refining products. These refining and chemical production units are further optimized and combined. Atmospheric diesel and vacuum diesel feedstocks are separated by aromatics extraction. The raffinate diesel is used as feedstock for steam cracking to produce chemical products such as hydrogen, methane, ethylene, propylene, cracked C4, cracked gasoline, and cracked heavy oil. The extracted diesel is used as feedstock for hydrocracking to produce refining products such as light hydrocarbons, gasoline, kerosene, diesel, and heavy oil.

[0009] Atmospheric diesel has a distillation range of 130–410℃ and is a heavy oil product obtained through atmospheric distillation, composed of alkanes, alkenes, cycloalkanes, and aromatics. Vacuum diesel has a distillation range of 350–500℃ and is a heavy oil product obtained through vacuum distillation, composed of alkanes, alkenes, cycloalkanes, and aromatics. Raffinate diesel is a heavy oil product obtained through aromatic extraction, mainly composed of alkanes, alkenes, and cycloalkanes, and contains almost no aromatics. Extracted diesel is a heavy oil product obtained through aromatic extraction, mainly composed of aromatics, and contains almost no alkanes, alkenes, or cycloalkanes.

[0010] The process flow is as follows:

[0011] Diesel feedstock (101) from outside the boundary is fed into the aromatics extraction unit, and processed through the extraction tower (A1), stripping tower (A2), and regeneration tower (A3) to obtain raffinate diesel (401), extracted diesel (402), and sludge (501). The solvent is repeatedly recycled within the aromatics extraction unit. The solvent is sulfolane or N-methylpyrrolidone, and the mass ratio of the solvent to the diesel feedstock is 3.0 to 4.0:1. Raffinate diesel (401) is washed in the water washing tower (A4) to become cracking feedstock (403), which is then fed into the cracking furnace (C1) of the steam cracking unit. Extracted diesel (402) is fed into the hydrocracking reactor (B1) of the hydrocracking unit. Sludge (501) flowing out from the top of the regeneration tower (A3) is discharged outside the boundary, and wastewater (502) flowing out from the bottom of the water washing tower (A4) is discharged outside the boundary. Diesel (402) and hydrogen are extracted and sent to the hydrocracking reactor (B1) for hydrocracking reaction. The outflowing reactants (405) enter the gas-liquid separator (B2). The gaseous hydrogen flowing out from the top of the separator is combined with the hydrogen flowing out from the cold box (D2) of the steam cracking unit and enters the hydrogen compressor (B3). After being pressurized, it returns to the hydrocracking reactor (B1). The liquid reactants flowing out from the bottom of the separator are separated by distillation in the light hydrocarbon tower (B4), gasoline tower (B5), and kerosene tower (B6) to obtain refined oil products such as light hydrocarbons (201), gasoline (202), kerosene (203), diesel (204), and heavy oil (205), which are then sent outside the area. The cracked feedstock (403) is fed into the cracking furnace (C1) of the steam cracking unit for steam cracking reaction. After being cooled by the quench boiler (C2) to terminate the cracking reaction, the cracked gas (404) is separated and processed by the quench oil tower (C3), quench water tower (C4), cracked gas compressor (C5), cold box (D2), demethanizer (D1), deethanerizer (D3), ethylene distillation tower (D4), depropanizer (D5), propylene distillation tower (D6), and debutanizer (D7) to obtain chemical products such as hydrogen (301), methane (302), ethylene (303), propylene (304), cracked C4 (305), cracked gasoline (306), and cracked heavy oil (307) and sent out of the area.

[0012] The process parameters are as follows:

[0013] The hydrocracking unit's hydrocracking reactor (B1) has a reaction temperature of 500–700℃, a reaction pressure of 0.2–0.5 MPaA, a reaction time of 1.0–5.0 s, and uses an amorphous silica-alumina catalyst or a shape-selective molecular sieve catalyst with alumina or silica-containing alumina as the support. The active components consist of three parts: molybdenum, cobalt, and nickel. As oxides, the content of molybdenum is 3.0–20.0 wt%, the content of cobalt is 0.5–5.0 wt%, and the content of nickel is 0.1–1.0 wt%.

[0014] The steam cracking reaction temperature of the residual atmospheric diesel feedstock in the cracking furnace (C1) of the steam cracking unit is 785-825℃, the reaction pressure is 0.14-0.22MPaA, and the mass ratio of dilution steam is DS:HC = 0.65-0.80:1.00;

[0015] The steam cracking reaction temperature of the residual vacuum diesel feedstock in the cracking furnace (C1) of the steam cracking unit is 770-810℃, the reaction pressure is 0.14-0.22MPaA, and the dilution steam mass ratio is DS:HC = 0.70-0.85:1.00;

[0016] The diesel feedstock (101) from outside the boundary is either atmospheric diesel (AGO) or vacuum diesel (VGO) or fed at a ratio of 0 to 100%. The aromatics extraction unit is set up with two parallel production lines, and the steam cracking unit performs separate furnace cracking to process atmospheric diesel and vacuum diesel respectively.

[0017] Cracked C4 (305) is processed by a butadiene extraction unit to obtain butadiene products, and cracked gasoline (306) is processed by a cracked gasoline hydrogenation unit and an aromatics extraction unit to obtain benzene, toluene and xylene products.

[0018] Beneficial effects:

[0019] This invention relates to a combined refining and chemical process for the comprehensive utilization of oil products. To control the increase of chemical products in refining output, an aromatics extraction unit, a steam cracking unit, and a hydrocracking unit are optimized and combined. Atmospheric and vacuum diesel are separated through aromatics extraction to obtain residual diesel, which is used as feedstock for steam cracking to produce hydrogen, methane, ethylene, propylene, cracked C4, cracked gasoline, and cracked heavy oil, among other chemical products. Extracted diesel is used as feedstock for hydrocracking to produce light hydrocarbons, gasoline, kerosene, diesel, and heavy oil, among other refining products. C4 is further processed through a butadiene extraction unit to obtain butadiene, and cracked gasoline is further processed through a cracked gasoline hydrotreating unit and an aromatics extraction unit to obtain benzene, toluene, and xylene. When the diesel feedstock enters the aromatics extraction unit at a rate of 1-4 million tons / year, the total yield of trienes and triphenylene products is 391,600-2,040,000 tons / year, with a total yield of 38.90-51.00 wt%, achieving good technical results. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0021] Figure 1In the diagram, A1 is an extraction tower, A2 is a stripping tower, A3 is a regeneration tower, A4 is a water washing tower, B1 is a hydrogenation reactor, B2 is a gas-liquid separator, B3 is a hydrogen compressor, B4 is a light hydrocarbon tower, B5 is a gasoline tower, B6 is a kerosene tower, C1 is a cracking furnace in a steam cracking unit, C2 is a quench boiler, C3 is a quench oil tower, C4 is a quench water tower, C5 is a cracked gas compressor, D1 is a methane tower, D2 is a cold box, D3 is a de-ethanizer tower, D4 is an ethylene distillation tower, D5 is a de-propaneizer tower, D6 is a propylene distillation tower, and D7 is a de-butaneizer tower.

[0022] 101 is diesel feedstock, 201 is light hydrocarbon, 202 is gasoline, 203 is kerosene, 204 is diesel, 205 is heavy oil, 301 is hydrogen, 302 is methane, 303 is external ethylene, 304 is propylene, 305 is cracked C4, 306 is cracked gasoline, 307 is cracked heavy oil, 401 is raked diesel, 402 is extracted diesel, 403 is cracked feedstock, 404 is cracked gas, 405 is reactant, 501 is sludge oil, and 502 is wastewater. Detailed Implementation

[0023] The process flow of this invention is as follows:

[0024] Diesel feedstock (101) from outside the boundary is fed into the aromatics extraction unit. After processing in the extraction tower (A1), stripping tower (A2), and regeneration tower (A3), residual diesel (401), extracted diesel (402), and sludge (501) are obtained. The solvent is repeatedly recycled in the aromatics extraction unit. The residual diesel (401) is washed in the water washing tower (A4) to become cracking feedstock (403) and fed into the cracking furnace (C1) of the steam cracking unit. The extracted diesel (402) is fed into the hydrocracking reactor (B1) of the hydrocracking unit. The sludge (501) flowing out from the top of the regeneration tower (A3) is sent outside the boundary, and the wastewater (502) flowing out from the bottom of the water washing tower (A4) is sent outside the boundary. Diesel (402) and hydrogen are extracted and sent to the hydrocracking reactor (B1) for hydrocracking reaction. The outflowing reactants (405) enter the gas-liquid separator (B2). The gaseous hydrogen flowing out from the top of the separator is combined with the hydrogen flowing out from the cold box (D2) of the steam cracking unit and enters the hydrogen compressor (B3). After being pressurized, it returns to the hydrocracking reactor (B1). The liquid reactants flowing out from the bottom of the separator are separated by distillation in the light hydrocarbon tower (B4), gasoline tower (B5), and kerosene tower (B6) to obtain refined oil products such as light hydrocarbons (201), gasoline (202), kerosene (203), diesel (204), and heavy oil (205), which are then sent outside the area. The cracked feedstock (403) is fed into the cracking furnace (C1) of the steam cracking unit for steam cracking reaction. After being cooled by the quench boiler (C2) to terminate the cracking reaction, the cracked gas (404) is separated and processed by the quench oil tower (C3), quench water tower (C4), cracked gas compressor (C5), cold box (D2), demethanizer (D1), deethanerizer (D3), ethylene distillation tower (D4), depropanizer (D5), propylene distillation tower (D6), and debutanizer (D7) to obtain chemical products such as hydrogen (301), methane (302), ethylene (303), propylene (304), cracked C4 (305), cracked gasoline (306), and cracked heavy oil (307) and sent out of the area.

[0025] Example 1

[0026] like Figure 1 The process flow shown in this embodiment relates to a combined refining and chemical method for comprehensive utilization of oil products. To control oil production and enhance chemical recovery, the aromatics extraction unit, steam cracking unit, and hydrocracking unit are optimized and combined. Process parameters are shown in Appendix Table 1. When 100% atmospheric diesel feedstock (101) enters the aromatics extraction process at a rate of 1 million tons / year, the total yield of trienes and benzenes is 507,700 tons / year, with a total yield of 50.77 wt%, achieving good technical results.

[0027] Example 2

[0028] like Figure 1The process flow shown in this embodiment relates to a combined refining and chemical method for comprehensive utilization of oil products. To control oil production and enhance chemical recovery, the aromatics extraction unit, steam cracking unit, and hydrocracking unit are optimized and combined. Process parameters are shown in the attached table. When the 100% vacuum diesel feedstock (101) enters the aromatics extraction process at a rate of 1 million tons / year, the total yield of trienes and benzenes is 391,600 tons / year, with a total yield of 39.16 wt%, achieving good technical results.

[0029] Example 3

[0030] like Figure 1 The process flow shown in this embodiment relates to a combined refining and chemical method for comprehensive utilization of oil products. To control oil production and enhance chemical recovery, the aromatics extraction unit, steam cracking unit, and hydrocracking unit are optimized and combined. Process parameters are shown in the attached table. When 2 million tons / year of 100% atmospheric diesel feedstock (101) enters the aromatics extraction process, the total yield of trienes and benzenes is 1.0078 million tons / year, with a total yield of 50.39 wt%, achieving good technical results.

[0031] Example 4

[0032] like Figure 1 The process flow shown in this embodiment relates to a combined refining and chemical method for comprehensive utilization of oil products. To control oil production and enhance chemical recovery, the aromatics extraction unit, steam cracking unit, and hydrocracking unit are optimized and combined. Process parameters are shown in the attached table. When the 100% vacuum diesel feedstock (101) enters the aromatics extraction process at a rate of 2 million tons / year, the total yield of trienes and benzenes is 777,900 tons / year, with a total yield of 38.90 wt%, achieving good technical results.

[0033] Example 5

[0034] like Figure 1 The process flow shown in this embodiment relates to a combined refining and chemical method for comprehensive utilization of oil products. To control oil production and enhance chemical recovery, the aromatics extraction unit, steam cracking unit, and hydrocracking unit are optimized and combined. Process parameters are shown in the attached table. When the feedstock of 75% atmospheric diesel and 25% vacuum diesel (101) enters the aromatics extraction process at a rate of 3 million tons / year, the total yield of trienes and benzenes is 1.4361 million tons / year, with a total yield of 47.87 wt%, achieving good technical results.

[0035] Example 6

[0036] like Figure 1The process flow shown in this embodiment relates to a combined refining and chemical method for comprehensive utilization of oil products. To control oil production and enhance chemical recovery, the aromatics extraction unit, steam cracking unit, and hydrocracking unit are optimized and combined. Process parameters are shown in the attached table. When the feedstock of 25% atmospheric diesel and 75% vacuum diesel (101) enters the aromatics extraction process at a rate of 3 million tons / year, the total yield of trienes and benzenes is 1.2619 million tons / year, with a total yield of 42.06 wt%, achieving good technical results.

[0037] Example 7

[0038] like Figure 1 The process flow shown in this embodiment relates to a combined refining and chemical method for comprehensive utilization of oil products. To control oil production and enhance chemical recovery, the aromatics extraction unit, steam cracking unit, and hydrocracking unit are optimized and combined. Process parameters are shown in the attached table. When 4 million tons / year of 100% atmospheric diesel feedstock (101) enters the aromatics extraction process, the total yield of trienes and benzenes is 2.04 million tons / year, with a total yield of 51.00 wt%, achieving good technical results.

[0039] Example 8

[0040] like Figure 1 The process flow shown in this embodiment relates to a combined refining and chemical method for comprehensive utilization of oil products. To control oil production and enhance chemical recovery, the aromatics extraction unit, steam cracking unit, and hydrocracking unit are optimized and combined. Process parameters are shown in the attached table. When the 100% vacuum diesel feedstock (101) enters the aromatics extraction process at a rate of 4 million tons / year, the total yield of trienes and benzenes is 1.5728 million tons / year, with a total yield of 39.32 wt%, achieving good technical results.

[0041] Table 1 Summary of the effects of Examples 1-2

[0042]

[0043] Table 2 Summary of Effects of Examples 3-4

[0044]

[0045] Table 3 Summary of Effects of Examples 5-6

[0046]

[0047] Table 4 Summary of Effects of Examples 7-8

[0048]

Claims

1. A combined oil refining and chemical process for the integrated utilization of oil products, which is provided with an aromatic extraction device, a steam cracking device and a hydrocracking device, characterized in that, Includes the following steps: (1) Diesel feedstock (101) is fed into the aromatics extraction unit and processed by the extraction tower (A1), stripping tower (A2) and regeneration tower (A3) to obtain raffinate diesel (401), extracted diesel (402) and sludge oil (501). The solvent is repeatedly recycled in the aromatics extraction unit. The operating pressure of the extraction tower (A1) is 0.15-0.35 MPaA and the operating temperature is 60-80℃. The operating pressure of the stripping tower (A2) is 0.15-0.35 MPaA and the operating temperature is 140-160℃. The operating pressure of the regeneration tower (A3) is 0.15-0.35 MPaA and the operating temperature is 50-70℃. (2) The residual diesel (401) is washed in the water washing tower (A4) to become the cracking feedstock (403) and sent to the cracking furnace (C1) in the steam cracking unit. The extracted diesel (402) is sent to the hydrocracking reactor (B1) in the hydrocracking unit. The sludge oil (501) flowing out from the top of the regeneration tower (A3) is sent out of the boundary. The wastewater (502) flowing out from the bottom of the water washing tower (A4) is sent out of the boundary. (3) Extract diesel (402) and hydrogen and send them into the hydrocracking reactor (B1) for hydrocracking reaction. The outflowing reactant (405) enters the gas-liquid separator (B2). The gaseous hydrogen flowing out from the top of the tank is combined with the hydrogen flowing out from the cold box (D2) of the steam cracking unit and enters the hydrogen compressor (B3). After pressurization, it returns to the hydrocracking reactor (B1). The liquid reactant flowing out from the bottom of the tank is separated by distillation in the light hydrocarbon tower (B4), gasoline tower (B5) and kerosene tower (B6) to obtain light hydrocarbon (201), gasoline (202), kerosene (203), diesel (204) and heavy oil (205) as refined products and sent out of the area. (4) The cracking feedstock (403) is fed into the cracking furnace (C1) of the steam cracking unit for steam cracking reaction. After being cooled by the quench boiler (C2) to terminate the cracking reaction, the cracked gas (404) is separated and processed by the quench oil tower (C3), quench water tower (C4), cracked gas compressor (C5), cold box (D2), demethanizer (D1), deethaner (D3), ethylene distillation tower (D4), depropanizer (D5), propylene distillation tower (D6), and debutanizer (D7) to obtain hydrogen (301), methane (302), and ethylene. olefins (303), propylene (304), cracked C4 (305), cracked gasoline (306), and cracked heavy oil (307) are discharged outside the boundary; the diesel feedstock (101) is atmospheric diesel or vacuum diesel, and the raffinate diesel (401) is raffinate atmospheric diesel or raffinate vacuum diesel; when the cracking feedstock (403) is raffinate atmospheric diesel, the steam cracking reaction temperature of the cracking furnace (C1) of the steam cracking unit is 785-825℃, the reaction pressure is 0.14-0.22MPaA, and the dilution steam mass ratio is DS:HC = 0.65-0.80:1.00; when the cracking feedstock (403) is raffinate vacuum diesel, the steam cracking reaction temperature in the cracking furnace (C1) of the steam cracking unit is 770-810℃, the reaction pressure is 0.14-0.22MPaA, and the dilution steam mass ratio is DS:HC = 0.70-0.85:1.

00.

2. The combined refining and chemical processing method for comprehensive utilization of oil products according to claim 1, characterized in that, In step (1), the solvent is sulfolane or N-methylpyrrolidone, and the mass ratio of the solvent to the diesel feedstock is 3.0 to 4.0:

1.

3. The combined refining and chemical processing method for comprehensive utilization of oil products according to claim 1, characterized in that, In step (3), the reaction temperature of the hydrogenation reactor (B1) is 500-700℃, the reaction pressure is 0.2-0.5MPaA, the reaction time is 1.0-5.0s, and the catalyst in the hydrogenation reactor (B1) is an amorphous silica-alumina catalyst or a shape-selective molecular sieve catalyst.

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