A method and system for low pressure ebullated bed processing of residual oil

Abstract

The present disclosure relates to a method and system for treating residual oil in a low pressure ebullated bed, which comprises: mixing a residual oil feedstock and a hydrogen donor, and then feeding the mixture into an ebullated bed reactor to contact with a catalyst under a pressure of 5-70 bar to perform a hydrogenation reaction, to obtain a hydrogenation reaction product and a catalyst-containing oil; subjecting the hydrogenation reaction product to a first separation to obtain a first gas phase and a high-boiling oil; subjecting the high-boiling oil to a stripping treatment to obtain a second gas phase and a stripping column bottom oil; subjecting the stripping column bottom oil to a second separation to obtain a third gas phase, a spent hydrogen donor, a light oil product and an atmospheric column bottom oil; subjecting the atmospheric column bottom oil to a third separation to obtain a fourth gas phase, a heavy oil product and an unconverted oil; subjecting the spent hydrogen donor to a regeneration treatment to obtain a regenerated hydrogen donor; and returning at least part of the regenerated hydrogen donor to the ebullated bed reactor. The method of the present disclosure can improve the conversion rate of the hydrogenation reaction and the yield of the liquid product.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of petroleum chemical industry, in particular, to a method and system for treating residual oil in a low-pressure ebullated bed. BACKGROUND

[0002] At present, there are four types of residual oil hydrogenation processes, namely fixed bed, ebullated bed, moving bed and slurry bed residual oil hydrogenation. The ebullated bed hydrogenation technology can replace catalysts online, has high catalyst utilization rate, and has been widely used in residual oil lightening. In addition, the device has long operation period and flexible operation. However, in the ebullated bed residual oil hydrogenation, the reaction system is in a high-pressure and hydrogen-containing state, the feedstock has poor properties and serious coking, and in addition, hydrogen molecules are easy to escape and leak due to their low molecular weight, which causes great safety risk. At the same time, under high pressure, the device has high equipment investment and high safety risk, which brings great trouble to the stable, safe and long-period operation of the ebullated bed residual oil hydrogenation device using the existing technology.

[0003] CN1388219A discloses a catalytic conversion method for reducing the olefin content of gasoline by using a hydrogen-donating component. The method is characterized by applying a catalytic cracking process to saturate light feedstocks and improve product properties. However, when treating poor heavy oil, especially high-viscosity heavy oil, the catalytic cracking reactor has serious catalyst coking, which seriously affects the long-period operation of the device.

[0004] CN1393524A and CN105567319B respectively disclose a method for lightening heavy and residual oil and a method for treating heavy oil. The characteristics of the methods are that distillate oil is used as a hydrogen donor, which is mixed with feedstock and catalyst under the action of hydrogen and then subjected to high-pressure hydrogen treatment or hydrocracking, and the hydrogen donor is subjected to fixed bed hydrogenation and recycling. The methods can treat heavy residual oil, but hydrogen and hydrogen donor participate in the reaction at the same time, the reaction pressure is high in the presence of hydrogen, and the hydrogen donor acts as an additive or an aid, which is not conducive to energy saving and consumption reduction of the device and increases the difficulty of device operation.

[0005] CN102504862A and CN105505449A respectively disclose a hydrogen-donating thermal cracking method and a hydrogen-donating coking method. The characteristics of the methods are that distillate oil is used as a hydrogen donor and mixed with heavy feedstock and then heated to a high temperature to make the feedstock undergo thermal cracking, thereby reducing the viscosity of the feedstock and reducing the yield of coke. However, the methods do not add catalysts, the loss of hydrogen donor is large during thermal cracking, and the efficiency is low.

[0006] CN113801691A discloses a method and system for producing ethylene device raw materials from residual oil, which is characterized in that the residual oil is heated together with hydrogen and then sent into a boiling bed hydrogenation reactor, and light hydrocarbons, naphtha, diesel, wax oil and unconverted oil are obtained by separation. However, the hydrogen reaction system pressure in the method is high, resulting in high equipment investment and high energy consumption, and hydrogen is easy to leak or pressure is easy to be connected under high pressure, which is not conducive to the long-period stable operation of the device.

[0007] In the prior art, hydrogen-donating thermal cracking is more commonly used in the viscosity reduction of crude oil. Common hydrogen donors include their own distillate oil, alcohol, formic acid and its salt, cyclohexene, hydrazine hydrate and triethylsilane, water, etc. The methods used include hydrogen-donating thermal cracking, microwave thermal cracking, hydrocracking, hydrofining, etc. Among them, hydrocracking or hydrofining requires the introduction of external hydrogen, and is operated under hydrogen conditions. The catalyst used is usually a solid catalyst, a fixed bed reactor is used, and the hydrogen donor is the distillate oil itself or is injected once with chemicals. The consumption of a large amount of chemicals and a large amount of hydrogen circulation leads to increased investment, and some by-products of the hydrogen donor may be difficult to separate from the product, resulting in unqualified product indicators. SUMMARY

[0008] The purpose of the present disclosure is to provide a method and system for processing residual oil in a low-pressure boiling bed, in order to solve the problems of low liquid product content, high safety risk and high equipment investment in the prior art.

[0009] To achieve the above-mentioned purpose, the first aspect of the present disclosure provides a method for processing residual oil in a low-pressure boiling bed, which comprises: mixing residual oil raw material and hydrogen donor, then entering a boiling bed reactor and contacting with a catalyst under a pressure of 5-70 bar to perform a hydrogenation reaction, to obtain a hydrogenation reaction product and a catalyst-containing oil; subjecting the hydrogenation reaction product to a first separation to obtain a first gas phase and a high-oil; subjecting the high-oil to a stripping treatment to obtain a second gas phase and a stripping column bottom oil; subjecting the stripping column bottom oil to a second separation to obtain a third gas phase, a virgin hydrogen donor, a light oil product and an atmospheric column bottom oil; subjecting the atmospheric column bottom oil to a third separation to obtain a fourth gas phase, a heavy oil product and unconverted oil; subjecting the virgin hydrogen donor to a regeneration treatment to obtain a regenerated hydrogen donor; and returning at least part of the regenerated hydrogen donor to the boiling bed reactor.

[0010] Optionally, the residual oil raw material is selected from one or more of atmospheric residual oil, vacuum residual oil, vacuum wax oil, coking wax oil, deasphalted oil and coal tar; the hydrogen donor is selected from one or more of naphthenes and / or naphthenes, preferably one or more of cyclohexane, methylcyclohexane, decalin and cyclohexadiene; and the catalyst is a supported nickel-molybdenum solid particle type catalyst and / or a supported nickel-molybdenum ultrafine powder type catalyst.

[0011] Optionally, the reaction conditions of the hydrogenation reaction include: reaction temperature of 150-450℃, reaction time of 0.5-10h, mass ratio of the hydrogen donor to the residual oil feedstock of 0.25-2, preferably 0.3-1.

[0012] Optionally, before the hydrogenation reaction, the mixed feedstock formed by the residual oil feedstock and the hydrogen donor is pressurized to 5-70bar, and then the mixed feedstock is heated to 150-450℃ after heat exchange with the hydrogenation reaction product.

[0013] Optionally, the first separation is performed in a cold / hot high-pressure separator; the second separation is performed in an atmospheric distillation column; the distillation cut point of the third gas phase to the spent hydrogen donor is 40-80℃, the distillation cut point of the spent hydrogen donor to the light oil product is 130-160℃, and the distillation cut point of the light oil product to the atmospheric column bottom oil is 300-360℃; the third separation is performed in a vacuum distillation column; the distillation cut point of the fourth gas phase to the heavy oil product is 300-360℃, and the distillation cut point of the heavy oil product to the unconverted oil is 480-540℃.

[0014] Optionally, the stripping treatment conditions include: temperature of 150-450℃, pressure of 0.5-50bar, and weight ratio of the stripping medium to the high-boiling oil of (0.01-0.5):1.

[0015] Optionally, the method further includes mixing the spent hydrogen donor with hydrogen gas and then feeding the mixture into a hydrogenation reactor to perform the regeneration treatment; the regeneration treatment conditions include: temperature of 150-250℃, pressure of 5-50bar, time of 0.1-1h, and volume ratio of the hydrogen gas to the spent hydrogen donor of (10-300):1.

[0016] Optionally, the ratio of the weight of the part of the regenerated hydrogen donor returned to the ebullated bed reactor to the total weight of the regenerated hydrogen donor is 0.2-1, preferably 0.8-1; the method further includes returning the catalyst-containing oil to the ebullated bed reactor.

[0017] The second aspect of the present disclosure provides a system for treating residual oil in a low-pressure ebullated bed, which comprises an ebullated bed reactor, a first separation device, a stripping device, an atmospheric distillation device, a second separation device, a third separation device, and a hydrogenation regeneration device; the ebullated bed reactor comprises a mixed feedstock inlet, a catalyst inlet, a circulating catalyst inlet, a hydrogenation reaction product outlet, a catalyst discharge outlet, and a catalyst-containing oil outlet; the first separation device comprises a hydrogenation reaction product inlet, a first gas phase outlet, and a high-separation oil outlet; the stripping device comprises a high-separation oil inlet, a second gas phase outlet, and a stripping tower bottom oil outlet; the second separation device comprises a stripping tower bottom oil inlet, a third gas phase outlet, a spent hydrogen donor outlet, a light oil product outlet, and an atmospheric tower bottom oil outlet; the third separation device comprises an atmospheric tower bottom oil inlet, a fourth gas phase outlet, a heavy oil product outlet, and an unconverted oil outlet; the hydrogenation regeneration device comprises a spent hydrogen donor inlet and a regenerated hydrogen donor outlet; the hydrogenation reaction product outlet of the ebullated bed reactor is in communication with the hydrogenation reaction product inlet of the first separation device; the high-separation oil outlet of the first separation device is in communication with the high-separation oil inlet of the stripping device; the stripping tower bottom oil outlet of the stripping device is in communication with the stripping tower bottom oil inlet of the second separation device; the spent hydrogen donor outlet of the second separation device is in communication with the spent hydrogen donor inlet of the hydrogenation regeneration device; the atmospheric tower bottom oil outlet of the second separation device is in communication with the atmospheric tower bottom oil inlet of the third separation device; and the regenerated hydrogen donor outlet of the hydrogenation regeneration device is in communication with the mixed feedstock inlet of the ebullated bed reactor.

[0018] Optionally, the system further comprises a catalyst circulating pump and a catalyst tank; the inlet of the catalyst circulating pump is in communication with the catalyst-containing oil outlet of the ebullated bed reactor; the outlet of the catalyst circulating pump is in communication with the circulating catalyst inlet of the ebullated bed reactor; the inlet of the catalyst tank is in communication with the catalyst discharge outlet of the ebullated bed reactor; and the outlet of the catalyst tank is in communication with the catalyst inlet of the ebullated bed reactor.

[0019] By the above technical solution, the hydrogen donor is used to replace the hydrogen or the hydrogen and hydrogen donor mixed hydrogen supply system in the prior art, which can reduce the reaction pressure of the hydrogenation reaction, reduce the risk of hydrogen leakage, and thus improve the safety of the ebullated bed for treating residual oil; the spent hydrogen donor is subjected to hydrogenation regeneration treatment, and part of the regenerated hydrogen donor is returned to the ebullated bed reactor for continuous reaction, which can realize the recycling use of the hydrogen donor and reduce the consumption of the hydrogen donor; in addition, by the method of the present disclosure, the conversion rate of the hydrogenation reaction and the yield of the liquid product can be improved.

[0020] Other features and advantages of the present disclosure will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure and serve to explain the principles of the present disclosure, but are not intended to limit the present disclosure. In the drawings:

[0022] Figure 1 is a schematic diagram of a method for treating residual oil in a low pressure ebullated bed according to the present disclosure.

[0023] Explanation of reference signs

[0024] P1, feed pump; P2, catalyst circulation pump; E, feed heat exchanger; F1, feed heating furnace; R1, ebullated bed reactor; D1, hot / cold high pressure separator; T1, stripping column; T2, atmospheric distillation column; T3, vacuum distillation column; TK1, catalyst tank; F2, heating furnace; R2, hydrogenation reactor; 1, residual oil feedstock; 2, hydrogen donor; 3, mixed feedstock; 4, heat-exchanged mixed feedstock; 5, preheated mixed feedstock; 6, hydrogenation reaction product; 7, heat-exchanged hydrogenation reaction product; 8, first gas phase; 9, high-vacuum oil; 10, second gas phase; 11, stripping column bottom oil; 12, third gas phase; 13, hydrogen; 14, hydrogen-donated hydrogen donor; 15, light oil product; 16, heated virgin hydrogen donor; 17, external hydrogen donor; 18, regenerated hydrogen donor; 19, atmospheric column bottom oil; 20, fourth gas phase; 21, heavy oil product; 22, unconverted oil; 23, 24, catalyst-containing oil; 25, catalyst discharge; 26, catalyst injection. DETAILED DESCRIPTION

[0025] The specific embodiments of the present disclosure will be described in detail hereinafter with reference to the drawings. It should be understood that the specific embodiments described herein are merely illustrative and explanatory and are not intended to limit the present disclosure.

[0026] In the present disclosure, the orientation words such as "upper" and "lower" used herein generally refer to the upper and lower of the device in the normal use state, for example, with reference to the drawing surface direction of Figure 1 "inner" and "outer" refer to relative to the outline of the device. In addition, the terms "first", "second", "third" are only for descriptive purposes and should not be construed as indicating or implying relative importance or implying the number of the indicated technical features. Therefore, the features defined as "first", "second", "third" can explicitly or implicitly include one or more features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0027] The first aspect of the present disclosure provides a method for treating residual oil in a low pressure ebullated bed, which comprises: mixing a residual oil feedstock and a hydrogen donor, and then feeding the mixture into an ebullated bed reactor to contact with a catalyst under a pressure of 5-70 bar to perform a hydrogenation reaction, to obtain a hydrogenation reaction product and a catalyst-containing oil; subjecting the hydrogenation reaction product to a first separation to obtain a first gas phase and a high-boiling oil; subjecting the high-boiling oil to a stripping treatment to obtain a second gas phase and a stripping column bottom oil; subjecting the stripping column bottom oil to a second separation to obtain a third gas phase, a spent hydrogen donor, a light oil product and an atmospheric column bottom oil; subjecting the atmospheric column bottom oil to a third separation to obtain a fourth gas phase, a heavy oil product and an unconverted oil; subjecting the spent hydrogen donor to a regeneration treatment to obtain a regenerated hydrogen donor; and returning at least part of the regenerated hydrogen donor to the ebullated bed reactor.

[0028] By the above technical solution, the hydrogen donor is used to replace the hydrogen or the hydrogen and hydrogen donor mixed hydrogen supply system in the prior art, which can reduce the reaction pressure of the hydrogenation reaction, reduce the risk of hydrogen leakage, and thus improve the safety of the ebullated bed for treating residual oil. The spent hydrogen donor is subjected to a hydrogenation regeneration treatment, and part of the regenerated hydrogen donor is returned to the ebullated bed reactor for continuous reaction, which can realize the recycling of the hydrogen donor and reduce the consumption of the hydrogen donor. In addition, by the method of the present disclosure, the conversion rate of the hydrogenation reaction and the yield of the liquid product can be improved.

[0029] The reaction device used in the present disclosure is an ebullated bed reactor with a catalyst circulating pump and a catalyst tank, and the system can have one or more ebullated bed reactors connected in series.

[0030] The method used in the present disclosure can treat more heavy oil with high viscosity and many impurities. For example, in one embodiment of the present disclosure, the residual oil feedstock is selected from one or more of atmospheric residual oil, vacuum residual oil, vacuum wax oil, coking wax oil, deasphalted oil and coal tar.

[0031] The hydrogen donor used in the present disclosure is selected from naphthenes and / or naphthenes, preferably one or more of cyclohexane, methylcyclohexane, decalin and cyclohexadiene. In this embodiment, the hydrogen donor is used to replace the hydrogen or the hydrogen and hydrogen donor mixed hydrogen supply system in the prior art, which can reduce the pressure during the hydrogen transfer reaction, further enhance the safety of the reaction, and at the same time improve the conversion rate of the hydrogen transfer reaction and the yield of the liquid product. The liquid product refers to the total of the light oil product and the heavy oil product.

[0032] The catalyst used in the present disclosure is conventionally selected in the art, and no special requirement is made in the present application. For example, in one specific embodiment of the present disclosure, the catalyst is a supported nickel-molybdenum solid particle type catalyst and / or a supported nickel-molybdenum ultrafine powder type catalyst.

[0033] In one embodiment, before the hydrogenation reaction, the mixed raw material formed by the residue feedstock and the hydrogen donor is pressurized to 5-70 bar by a feed pump, then enters the tube side of the feed heat exchanger and exchanges heat with the hydrogenation reaction product in the shell side of the feed heat exchanger, and finally is heated to 150-450℃ by a feed heating furnace.

[0034] In this embodiment, the heat exchange between the mixed raw material and the hydrogenation reaction product can recover the heat in the hydrogenation reaction product and reduce the heat loss of the system. By heating and pressurizing the mixed raw material to the reaction temperature before the hydrogenation reaction, the performance of the hydrogenation reaction can be further enhanced, the generation of by-products can be reduced, and the conversion rate of the hydrogenation reaction can be further improved.

[0035] In one embodiment, the reaction conditions of the hydrogenation reaction include: the reaction temperature is 150-450℃, preferably 250-400℃, and further preferably 280-350℃; the reaction time is 0.5-10 h, preferably 1-8 h, and further preferably 2-6 h; the reaction pressure is preferably 8-65 bar, and further preferably 10-60 bar; and the mass ratio of the hydrogen donor to the residue feedstock is 0.3-2, and preferably 0.3-1.

[0036] In this embodiment, since the hydrogen donor is used instead of the hydrogen or hydrogen-donor system in the prior art, on the one hand, the reaction pressure is greatly reduced, the safety hazard caused by hydrogen leakage is reduced, and the safety of the device is increased; on the other hand, the hydrogenation reaction under suitable conditions can also enhance the conversion rate of the hydrogenation reaction and the yield of the liquid product.

[0037] The cold / hot high-pressure separator, the atmospheric distillation column, the stripping column and the vacuum distillation column used in the present disclosure are all conventional choices in the art, and the present application does not make special requirements. In order to improve the separation effect of each component, the cut points of the fractions between each component are limited. Specifically, in the second separation, the cut point of the third gas phase and the raw hydrogen donor is 40-80℃, and preferably 45-75℃; the cut point of the raw hydrogen donor and the light oil product is 130-160℃, and preferably 135-155℃; the cut point of the light oil product and the atmospheric column bottom oil is 300-360℃, and preferably 305-355℃. In the third separation, the cut point of the fourth gas phase and the heavy oil product is 300-360℃, and preferably 305-355℃; the cut point of the heavy oil product and the unconverted oil is 480-540℃, and preferably 485-530℃.

[0038] In the above embodiments, the pressure in the pressure-reduced distillation column is a negative pressure of 1-100 mmHg; the first, second, third and fourth gas phases are light hydrocarbons, wherein the first, second, third and fourth gas phases are led out of the system.

[0039] In one embodiment, the conditions of the stripping treatment include: a temperature of 150-450 ℃, a pressure of 0.5-50 bar, and a weight ratio of the stripping medium to the high-boiling oil of (0.01-0.5):1. In this embodiment, the high-boiling oil is brought into contact with the stripping medium in the stripping column to perform the stripping treatment, so that the impurities in the high-boiling oil can be removed from the device with the stripping medium. The stripping medium used in the stripping treatment is a conventional selection in the art, and no special requirement is made in the present application. For example, the stripping medium can be water vapor.

[0040] In one embodiment, the method further includes: bringing the spent hydrogen donor mixed with hydrogen into a heating furnace to perform heating, and then bringing the heated material into a hydrogenation reactor to contact with the regenerated reaction catalyst to perform the regeneration treatment; the conditions of the regeneration treatment include: a temperature of 150-250 ℃, a pressure of 5-50 bar, a time of 0.1-1 h, and a volume ratio of the hydrogen to the spent hydrogen donor of (10-300):1.

[0041] In this embodiment, the regenerated reaction catalyst used in the present disclosure is a conventional selection in the art, and no special requirement is made in the present application. For example, the regenerated reaction catalyst can be selected from one or more of non-noble metal catalysts such as Ni and Mo and / or noble metal catalysts such as Pt and Pd. In addition, in order to further improve the conversion rate of the hydrogenation reaction and the yield of the liquid product, a part of the regenerated hydrogen donor is returned to the ebullated bed reactor to continue the hydrogenation reaction, and another part of the regenerated hydrogen donor is sent out of the system as a light fraction; wherein the ratio of the weight of the part of the regenerated hydrogen donor returned to the ebullated bed reactor to the total weight of the regenerated hydrogen donor is 0.2-1, and preferably 0.8-1.

[0042] In one embodiment, the method further includes: bringing the catalyst-containing oil back to the ebullated bed reactor to continue the hydrogenation reaction, and sending the obtained catalyst to a catalyst tank, and the catalyst output from the outlet of the catalyst tank enters the ebullated bed reactor to perform the hydrogenation reaction.

[0043] In the above embodiments, by bringing part of the regenerated hydrogen donor and the catalyst-containing oil back to the ebullated bed reactor to continue the hydrogenation reaction, the addition amount of the hydrogen donor and the raw material can be reduced, and thus the economic benefit of the device can be improved.

[0044] In one of the above embodiments, as shown in Figure 1 the method for low-pressure ebullated bed treatment of residual oil includes:

[0045] After mixing the residue feedstock 1 and hydrogen donor 2 to form a mixed feedstock, the mixed feedstock is pressurized to 5-70 bar by feed pump P1, then the mixed feedstock is heated to 150-450°C by feed heat exchanger E and feed heater F1, and then fed into ebullated bed reactor R1 to contact catalyst 3 injected from TK1 to perform a hydrogenation reaction, to obtain a hydrogenation reaction product and a catalyst-containing oil; the reaction conditions of the hydrogenation reaction include: a reaction temperature of 150-450°C, a reaction time of 0.5-10 h, and a mass ratio of the hydrogen donor to the residue feedstock of 2 or less.

[0046] The hydrogenation reaction product 6 is heated by feed heat exchanger E, and then enters high-pressure separator D1 to separate to obtain first gas phase 8 and high-boiling oil 9; the high-boiling oil 9 is fed into stripping column T1 to contact a stripping medium to perform a stripping treatment, to obtain second gas phase 10 and stripping column bottom oil 11, wherein the stripping treatment conditions include: a temperature of 150-450°C, a pressure of 0.5-50 bar, and a weight ratio of the stripping medium to the high-boiling oil of (0.01-0.5):1; the stripping medium is steam.

[0047] The stripping column bottom oil 11 is fed into atmospheric distillation column T2 to obtain third gas phase 12 (distillation range of 40-80°C), raw hydrogen donor 14 (distillation range of 80-140°C), light oil product 15 (distillation range of 140-350°C), and atmospheric column bottom oil 19 (distillation range of >350°C); the atmospheric column bottom oil 19 is fed into vacuum distillation column T3 to further distill under a negative pressure of 1-100 mmHg to obtain fourth gas phase 20 (distillation range of 40-120°C), heavy oil product 21 (distillation range of 350-520°C), and unconverted oil 22 (distillation range of >520°C).

[0048] The raw hydrogen donor 14 is mixed with hydrogen 13, heated by heater F2, and then fed into hydrogenation reactor R2 to perform a regeneration treatment at 150-250°C and 5-50 bar for 0.1-1 h to obtain a regenerated hydrogen donor; at least part of the regenerated hydrogen donor 18 is returned to the inlet of feed pump P1, and another part of the hydrogen donor 17 is discharged from the system as an external light fraction oil; the weight ratio of the part of the regenerated hydrogen donor 18 to the other part of the regenerated hydrogen donor is (0.1-99):1.

[0049] The second aspect of the present disclosure provides a system for processing residual oil in a low pressure ebullated bed, which comprises an ebullated bed reactor, a first separation device, a stripping device, an atmospheric distillation device, a second separation device, a third separation device and a hydrogenation regeneration device; the ebullated bed reactor comprises a mixed feedstock inlet, a catalyst inlet, a circulating catalyst inlet, a hydrogenation reaction product outlet, a catalyst discharge outlet and a catalyst-containing oil outlet; the first separation device comprises a hydrogenation reaction product inlet, a first gas phase outlet and a high-boiling oil outlet; the stripping device comprises a high-boiling oil inlet, a second gas phase outlet and a stripping column bottom oil outlet; the second separation device comprises a stripping column bottom oil inlet, a third gas phase outlet, a spent hydrogen donor outlet, a light oil product outlet and an atmospheric column bottom oil outlet; the third separation device comprises an atmospheric column bottom oil inlet, a fourth gas phase outlet, a heavy oil product outlet and an unconverted oil outlet; the hydrogenation regeneration device comprises a spent hydrogen donor inlet and a regenerated hydrogen donor outlet;

[0050] The hydrogenation reaction product outlet of the ebullated bed reactor is in communication with the hydrogenation reaction product inlet of the first separation device, so that the hydrogenation reaction product can enter the first separation device for first separation; the high-boiling oil outlet of the first separation device is in communication with the high-boiling oil inlet of the stripping device, so that the high-boiling oil can enter the stripping column for stripping treatment; the stripping column bottom oil outlet of the stripping device is in communication with the stripping column bottom oil inlet of the second separation device, so that the stripping column bottom oil can enter the second separation device for second separation; the spent hydrogen donor outlet of the second separation device is in communication with the spent hydrogen donor inlet of the hydrogenation regeneration device, so that the spent catalyst can enter the hydrogenation regeneration device for regeneration treatment; the atmospheric column bottom oil outlet of the second separation device is in communication with the atmospheric column bottom oil inlet of the third separation device, so that the atmospheric column bottom oil can enter the third separation device for third separation; the regenerated hydrogen donor outlet of the hydrogenation regeneration device is in communication with the mixed feedstock inlet of the ebullated bed reactor, so that the regenerated catalyst can return to the ebullated bed reactor.

[0051] In an embodiment, the system further comprises a catalyst circulating pump and a catalyst tank; the inlet of the catalyst circulating pump is in communication with the catalyst-containing oil outlet of the ebullated bed reactor, and the outlet of the catalyst circulating pump is in communication with the circulating catalyst inlet of the ebullated bed reactor, so that the catalyst-containing oil can return to the ebullated bed reactor for further hydrogenation reaction through the catalyst circulating pump; the inlet of the catalyst tank is in communication with the catalyst discharge outlet of the ebullated bed reactor; and the outlet of the catalyst tank is in communication with the catalyst inlet of the ebullated bed reactor, so that the catalyst can enter the ebullated bed reactor for hydrogenation reaction through the catalyst tank.

[0052] The embodiments of the present application will be described in detail below with examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. The specific conditions not specified in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, which are all conventional products that can be obtained by purchase.

[0053] The residue feedstock used in the following examples and comparative examples is vacuum residue, and the specific parameters are shown in Table 1; the catalyst is Ni / Mo@Al2O3 solid catalyst.

[0054] Table 1 Parameters of residue feedstock

[0055] Indicator Value Density (20°C) / (g / cm 3 )]]> 1073 Viscosity (20°C) / (mPa-s) 900 Sulfur wt% 3.6 Ni (ppm) 41 V (ppm) 108 Asphaltene wt% 11

[0056] Example 1

[0057] The mixed feedstock formed by mixing 100 t / h of residue feedstock 1 (vacuum residue) and hydrogen donor 2 (cyclohexane, the amount of one-time loading is 100 t, and the stable flow rate is 10 t / h) is pressurized to 70 bar by feed pump P1, then the mixed feedstock is heated to 425℃ by feed heat exchanger E and feed heating furnace F1 after heat exchange, and then sent into ebullated bed reactor R1 to contact with catalyst 3 (the amount of one-time loading is 20 t, and the stable flow rate is 2 t / h) injected from TK1 to carry out hydrogenation reaction, to obtain hydrogenation reaction product and catalyst-containing oil; the reaction conditions of hydrogenation reaction include: the reaction temperature is 425℃, the reaction pressure is 70 bar, the reaction time is 1 h, and the mass ratio of hydrogen donor to residue feedstock is 0.5:1.

[0058] The hydrogenation reaction product 6 is heat-exchanged by feed heat exchanger E, and then enters high-pressure separator D1 to separate to obtain first gas phase 8 and high-boiling oil 9; the high-boiling oil 9 is sent into stripping column T1 to contact with stripping medium for stripping treatment to obtain second gas phase 10 and stripping column bottom oil 11, wherein the conditions of stripping treatment include: the temperature is 290℃, the pressure is 15 bar, and the weight ratio of stripping medium to high-boiling oil is 0.1:1; the stripping medium is water vapor.

[0059] The stripping column bottom oil 11 is sent into atmospheric distillation column T2 to obtain third gas phase 12 (the distillation range is 40-80℃), raw hydrogen donor 14 (the distillation range is 80-140℃), light oil product 15 (the distillation range is 140-350℃) and atmospheric column bottom oil 19 (the distillation range is >350℃); the atmospheric column bottom oil 19 is sent into vacuum distillation column T3 to further distill under 7 mmHg negative pressure to obtain fourth gas phase 20 (the distillation range is 40-120℃), heavy oil product 21 (the distillation range is 350-520℃) and unconverted oil 22 (the distillation range is >520℃).

[0060] The hydrogen donor 14 to be mixed with hydrogen 13 is heated by heating furnace F2 and then enters the hydrogenation reactor R2. The hydrogenation reaction is carried out at 200°C and 20 bar for 0.5 h, and the regenerated hydrogen donor is obtained. At least part of the regenerated hydrogen donor 18 (90 t / h) is returned to the inlet of the feed pump PI, and the other part of the hydrogen donor 17 is discharged from the system as a light fraction oil. The weight ratio of the regenerated hydrogen donor 18 to the other part of the regenerated hydrogen donor is 9:1. The product properties are shown in Table 2.

[0061] Example 2

[0062] The method for treating residual oil in a low-pressure ebullated bed is the same as in Example 1, except that the mass ratio of the hydrogen donor to the raw oil is 0.3:1. The product properties are shown in Table 2.

[0063] Example 3

[0064] The method for treating residual oil in a low-pressure ebullated bed is the same as in Example 1, except that the mass ratio of the hydrogen donor to the raw oil is 0.2:1. The product properties are shown in Table 2.

[0065] Example 4

[0066] The method for treating residual oil in a low-pressure ebullated bed is the same as in Example 1, except that the mass ratio of the hydrogen donor to the raw oil is 0.1:1. The product properties are shown in Table 2.

[0067] Comparative Example 1

[0068] The raw oil and the catalyst are mixed after being pressurized and heated, respectively. Hydrogen is compressed by a new hydrogen compressor and heated by a hydrogen heating furnace, and then mixed with the raw oil and the catalyst to enter the ebullated bed reactor. The reaction pressure is 180 bar, the reaction temperature is 430°C, the hydrogen partial pressure is 110 bar, and the catalyst-oil ratio is 200 ppm. The product properties are shown in Table 2.

[0069] Comparative Example 2

[0070] The method for treating residual oil in a low-pressure ebullated bed is the same as in Example 1, except that the hydrogen donor system is a mixed system of hydrogen and hydrogen donor, wherein the hydrogen donor is hydrodesirable diesel, the reaction pressure is 180 bar, the hydrogen partial pressure is 140 bar, and the weight ratio of the hydrogen donor to the residual oil raw material is 0.15:1. The product properties are shown in Table 2.

[0071] Table 2 Product properties of examples and comparative examples

[0072]

[0073]

[0074] According to the data in Examples 1-2 and Comparative Examples 1-2 shown in Table 2, it can be seen that the method and system of the present disclosure can improve the conversion rate of the reaction and the yield of the liquid product; and the use of the hydrogen donor can reduce the reaction pressure of the hydrogenation reaction, reduce the risk of hydrogen leakage, and increase the safety of the system of the present disclosure. At the same time, the hydrogen donor to be regenerated is subjected to hydrogenation regeneration treatment, and part of the regenerated hydrogen donor is returned to the ebullated bed reactor for continuous reaction, which can realize the recycling use of the hydrogen donor and reduce the consumption of the hydrogen donor; by comparing the data in Examples 1-2 and Examples 3-4, it can be seen that when the mass ratio of the hydrogen donor to the raw oil is limited to 0.3-1, the reaction effect is good.

[0075] The preferred embodiments of the present disclosure are described in detail above with reference to the accompanying drawings, but the present disclosure is not limited to the specific details in the above-described embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0076] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present disclosure.

[0077] Furthermore, any combination of various different embodiments of the present disclosure can also be made, as long as it does not deviate from the idea of the present disclosure, and it should also be considered as disclosed by the present disclosure.

Claims

1. A process for the low pressure ebullated bed processing of residual oil, characterized in that, The method comprises: mixing a residual oil feedstock and a hydrogen donor, and then feeding the mixture into a ebullated bed reactor and contacting the mixture with a catalyst under a pressure of 5-70 bar to perform a hydrogenation reaction, thereby obtaining a hydrogenation reaction product and a catalyst-containing oil; the residual oil feedstock is selected from one or more of atmospheric residue, vacuum residue, vacuum gas oil, coking gas oil, deasphalted oil and coal tar; the hydrogen donor is selected from cycloalkanes and / or cycloalkenes; the reaction conditions of the hydrogenation reaction include a reaction temperature of 150-450 ℃, a reaction time of 0.5-10 h, and a mass ratio of the hydrogen donor to the residual oil feedstock of 0.25-2; subjecting the hydrogenation reaction product to a first separation to obtain a first gas phase and a high-boiling oil; subjecting the high-boiling oil to a stripping treatment to obtain a second gas phase and a stripping column bottom oil; subjecting the stripping column bottom oil to a second separation to obtain a third gas phase, a spent hydrogen donor, a light oil product and an atmospheric column bottom oil; subjecting the atmospheric column bottom oil to a third separation to obtain a fourth gas phase, a heavy oil product and an unconverted oil; subjecting the spent hydrogen donor to a regeneration treatment to obtain a regenerated hydrogen donor; and returning at least part of the regenerated hydrogen donor to the ebullated bed reactor.

2. The method of claim 1, wherein, the hydrogen donor is selected from one or more of cyclohexane, methylcyclohexane, decalin and cyclohexadiene; the catalyst is a supported nickel-molybdenum solid particulate catalyst and / or a supported nickel-molybdenum ultrafine powder catalyst.

3. The method of claim 1, wherein, the mass ratio of the hydrogen donor to the residual oil feedstock is 0.3-1.

4. The method of claim 1, wherein, Before the hydrogenation reaction is performed, the mixture of the residual oil feedstock and the hydrogen donor is pressurized to 5-70 bar, and then the mixture is heat-exchanged with the hydrogenation reaction product and then heated to 150-450 ℃.

5. The method of claim 1, wherein, the first separation is performed in a cold / hot high-pressure separator; the second separation is performed in an atmospheric distillation column; the fraction cut point of the third gas phase and the spent hydrogen donor is 40-80 ℃, the fraction cut point of the spent hydrogen donor and the light oil product is 130-160 ℃, and the fraction cut point of the light oil product and the atmospheric column bottom oil is 300-360 ℃; the third separation is performed in a vacuum distillation column; the fraction cut point of the fourth gas phase and the heavy oil product is 300-360 ℃, and the fraction cut point of the heavy oil product and the unconverted oil is 480-540 ℃.

6. The method of claim 1, wherein, the conditions of the stripping treatment include a temperature of 150-450 ℃, a pressure of 0.5-50 bar, and a weight ratio of the stripping medium to the high-boiling oil of (0.01-0.5):

1.

7. The method of claim 1, wherein, The method further comprises, after the spent hydrogen donor is mixed with hydrogen, feeding the mixture into a hydrogenation reactor to perform the regeneration treatment; the conditions of the regeneration treatment include a temperature of 150-250 ℃, a pressure of 5-50 bar, a time of 0.1-1 h, and a volume ratio of the hydrogen to the spent hydrogen donor of (10-300):

1.

8. The method of claim 1, wherein, The ratio of the weight of the part of the regenerated hydrogen donor returned to the ebullated bed reactor to the total weight of the regenerated hydrogen donor is 0.2-1. The method further comprises returning the catalyst-containing oil to the ebullated bed reactor.

9. The method of claim 1, wherein, The ratio of the weight of the part of the regenerated hydrogen donor returned to the ebullated bed reactor to the total weight of the regenerated hydrogen donor is 0.8-1.

10. A system for performing a low pressure ebullated bed treatment of residual oil by the process of any one of claims 1 to 9, characterized in that, The system comprises an ebullated bed reactor, a first separation device, a stripping device, a second separation device, a third separation device and a hydrogenation regeneration device; The ebullated bed reactor comprises a mixed feedstock inlet, a catalyst inlet, a circulating catalyst inlet, a hydrogenation reaction product outlet, a catalyst discharge outlet and a catalyst-containing oil outlet; The first separation device comprises a hydrogenation reaction product inlet, a first gas phase outlet and a high-separation oil outlet; The stripping device comprises a high-separation oil inlet, a second gas phase outlet and a stripping column bottom oil outlet; The second separation device comprises a stripping column bottom oil inlet, a third gas phase outlet, a spent hydrogen donor outlet, a light oil product outlet and an atmospheric column bottom oil outlet; The third separation device comprises an atmospheric column bottom oil inlet, a fourth gas phase outlet, a heavy oil product outlet and an unconverted oil outlet; The hydrogenation regeneration device comprises a spent hydrogen donor inlet and a regenerated hydrogen donor outlet; The hydrogenation reaction product outlet of the ebullated bed reactor is in communication with the hydrogenation reaction product inlet of the first separation device; the high-separation oil outlet of the first separation device is in communication with the high-separation oil inlet of the stripping device; the stripping column bottom oil outlet of the stripping device is in communication with the stripping column bottom oil inlet of the second separation device; the spent hydrogen donor outlet of the second separation device is in communication with the spent hydrogen donor inlet of the hydrogenation regeneration device; the atmospheric column bottom oil outlet of the second separation device is in communication with the atmospheric column bottom oil inlet of the third separation device; and the regenerated hydrogen donor outlet of the hydrogenation regeneration device is in communication with the mixed feedstock inlet of the ebullated bed reactor.

11. The system of claim 10, wherein, The system further comprises a catalyst circulating pump and a catalyst tank; The inlet of the catalyst circulating pump is in communication with the catalyst-containing oil outlet of the ebullated bed reactor; the outlet of the catalyst circulating pump is in communication with the circulating catalyst inlet of the ebullated bed reactor; the inlet of the catalyst tank is in communication with the catalyst discharge outlet of the ebullated bed reactor; and the outlet of the catalyst tank is in communication with the catalyst inlet of the ebullated bed reactor.

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