Wax oil hydroprocessing process

Abstract

The application discloses a wax oil hydroprocessing method. By timely removing reaction products and separating, and setting catalyst grading according to different components, the raw oil can be subjected to step-by-step targeted hydrogenation reaction in the reactor, so that the problem that the blending ratio is limited due to the incapability of better controlling the hydrogenation depth of the blended catalytic diesel and wax oil raw material is solved, the content of aromatic hydrocarbons in heavy naphtha in the hydrocracking product is greatly increased, and the product quality of diesel and tail oil is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of petroleum refining, and particularly relates to a wax oil hydroprocessing method. BACKGROUND

[0002] With the adjustment of domestic economic structure and the slowdown of economic growth, the growth rate of diesel consumption slows down, and the market demand for jet fuel and chemical raw materials gradually recovers. In particular, the energy structure transformation period is coming, and the change of consumption structure will bring challenges to the adaptability of China's refining device structure. Hydrocracking technology is the core of the combination of "oil and chemical fibers" in the refining structure, which can produce high-quality jet fuel, diesel, lubricating oil base oil raw materials, catalytic reforming raw materials, and ethylene raw materials. The wax oil hydrogenation device can also blend catalytic cracking diesel, coking diesel, and other inferior diesel to produce chemical materials, high-quality gasoline, and other products, realizing the high-value utilization of surplus diesel.

[0003] Patents CN103773495A, CN101875856A, CN102465035A, and CN1896192A disclose the process technology of blending catalytic cracking light cycle oil in the wax oil hydroprocessing process, the main purpose of which is to produce high-quality catalytic cracking raw materials, or to realize the coupling technology of catalytic cracking light cycle oil circulating between the wax oil hydroprocessing device and the catalytic cracking device, achieving clean production of the catalytic cracking device.

[0004] CN112410068A discloses a wax oil hydrocracking device and a method for producing 5# industrial white oil. Catalytic diesel and coking diesel are mixed with light wax oil from conventional vacuum distillation to form a mixed raw material, which enters a hydrogenation refining reactor and a hydrocracking reactor in turn; the cracking reaction product is subjected to gas-liquid separation in a cold-hot high-low separator; the reaction oil enters a flash tank after passing through a hydrogen sulfide stripping tower; the reaction oil at the bottom of the flash tank is heated and enters a fractionating column for cutting, and naphtha, aviation fuel, industrial white oil, and tail oil are obtained.

[0005] In the above patents, the mixed wax oil and blending oil are directly hydrogenated, the hydrogenation depth of the blending oil cannot be effectively controlled, and the blending ratio is limited, which affects the flexibility of the device.

[0006] CN109988630A discloses a wax oil hydrogenation method and system, which extracts the hydrogenation treated gas phase stream of the wax oil raw oil through step-by-step hydrogenation treatment of the stream, carries out gas-liquid separation between the two-step hydrogenation treatment, and feeds the hydrogenation treated gas phase stream into a separately carried out hydrofining reaction together with the catalytic cracking light cycle oil, so as to control the hydrogenation depth of the catalytic cracking light cycle oil, finally improve the content of aromatic hydrocarbons in the catalytic cracking gasoline, and thus improve the octane number of the catalytic cracking gasoline; in the method, although the hydrogen sulfide and ammonia in the wax oil hydrogenation product oil control the hydrogenation treatment depth of the catalytic diesel oil, due to the plug flow reaction process of the fixed bed reactor, there are still more fractions that are excessively opened or cracked, which limits the further improvement of the content of aromatic hydrocarbons in the gasoline.

[0007] Patent CN110938466A controls the cracking depth of different size fraction oils by controlling the content of different pore sizes, different molecular sieves and different active metals in the hydrofining reactor and the hydrocracking reactor, improves the product quality of high aromatic potential heavy naphtha, aviation kerosene, diesel oil and tail oil, reduces the light hydrocarbon yield, and effectively improves the economic benefit of the device. However, in the method, due to the limitation of thermodynamic equilibrium, the product quality improvement is limited. SUMMARY

[0008] In view of the deficiencies of the prior art, the purpose of the present application is to provide a wax oil hydrogenation treatment method, which can make the raw oil in the reactor perform gradient targeted hydrogenation reaction by timely removing the reaction products and separating them, and setting the catalyst grading according to different components, thereby solving the problem that the blending ratio is limited due to the inability to better control the hydrogenation depth of the blended catalytic diesel oil and wax oil raw material, greatly increasing the content of aromatic hydrocarbons in the heavy naphtha in the hydrogenation cracking product, and improving the product quality of diesel oil and tail oil.

[0009] The present application provides a wax oil hydrogenation treatment method, comprising the following steps:

[0010] (1) The wax oil and the blended catalytic diesel oil are heated and then enter the middle part of the hydrogenation pretreatment reactor, and the middle part of the reactor is provided with a cavity section; after flashing, the light components enter the upper part of the hydrogenation treatment catalyst, and the heavy components enter the lower part of the hydrogenation treatment catalyst; hydrogen gas enters from the bottom of the reactor and is in thin film contact with the heavy components of the raw oil flowing down in the middle part for hydrogenation;

[0011] (2) In step (1), the heavy components enter the middle part of the hydrogenation cracking reactor after hydrogenation pretreatment, and the distillate oil is flashed, the light distillate enters the upper part of the cracking catalyst bed layer, and the bed layer number is 1-3 layers; the heavy distillate enters the lower part of the cracking catalyst bed layer, and the lower part of the cracking catalyst bed layer is 2-8 layers; wherein the average pore size of the lower part of the cracking catalyst is 1-5 nm larger than that of the upper part of the cracking catalyst;

[0012] (3) The light components upward in step (1) flow out from the top of the reactor after the hydrogen pretreatment, and after condensation, a high-aromatic naphtha product is obtained, and the non-condensed gas can be used as recycle hydrogen after selective desulfurization;

[0013] (4) The heavy fraction in step (2) is opened ring and cracked into a naphtha fraction, a middle distillate oil, and a hydrogen-saturated unconverted oil under the action of a cracking catalyst and hydrogen;

[0014] (5) The naphtha fraction and the middle oil fraction obtained in step (4) flow upward out of the top of the reactor together with hydrogen, and a high-aromatic naphtha fraction is obtained after condensation, and the non-condensed gas can be used as recycle hydrogen after selective desulfurization; the middle distillate oil obtained in step (4) is cracked and opened ring again when flowing upward through the cracking catalyst bed again.

[0015] Further, the method further comprises step (6): the unconverted oil obtained in step (4) is stripped in a stripping tower, and the heavy fraction is sent out as an ethylene cracking material product or returned to the hydrogenation cracking reactor inlet for cracking again; the light fraction is condensed to obtain a naphtha fraction oil product, and the non-condensed gas is used as recycle hydrogen after selective desulfurization.

[0016] The present application takes wax oil and catalytic diesel as raw materials, mainly produces high-aromatic naphtha and saturated linear alkane chemical materials, solves the problem of inconsistent cracking and hydrogenation depth caused by large differences in fraction composition in the process of blending catalytic diesel with wax oil, and further improves the aromatic content in naphtha and fully resolves the excess diesel intermediate fraction in the refinery.

[0017] The wax oil in step (1) is straight-run wax oil, vacuum wax oil, coking wax oil, etc., and the catalytic diesel can be full-range catalytic diesel, catalytic light diesel or catalytic heavy diesel.

[0018] In the present application, the hydrogen pretreatment reactor and the hydrogenation cracking reactor are both middle feeding, and the middle part of the hydrogen pretreatment reactor and the hydrogenation cracking reactor is provided with a light-heavy separation chamber, and the volume V0 of the separation chamber is 0.5% to 30% of the effective volume V of the hydrogen pretreatment reactor and the hydrogenation cracking reactor, and is preferably 1% to 5%.

[0019] Further, the separation cavity can be a cavity or can be placed with packing or trays. The packing or trays are in the form of conventional in the art, such as the packing can be selected from one or more of the following: Pall ring, Raschig ring, K-type saddle ring, saddle type, open ring type, half ring, ladder ring, double arc, Haylor ring, conjugate ring, flat ring, flower ring and other random packing, or the packing can be selected from metal or ceramic corrugated packing. The trays are one or more of the following: bubble cap tray, sieve tray, float valve tray, mesh tray, tongue-shaped tray, guide sieve tray, multi-downcomer tray, and other trays with downcomer, or can be cross-flow sieve tray, cross-flow corrugated tray and other trays without downcomer. Preferably, the float valve tray, sieve tray and other high-efficiency trays.

[0020] The upper part of the hydrogenation pretreatment reactor is placed with 1-3 layers of catalyst. When two or more layers of catalyst are placed, the hydrogenation refining catalyst and the hydrocracking catalyst are sequentially filled from top to bottom. The volume and the number of layers of the two types of catalysts can be determined according to the process conditions.

[0021] Further, in the above technical solution, the lower bed of the hydrogenation pretreatment reactor in step (1) is provided with at least two layers. The hydrogenation treatment catalyst and the medium oil type cracking catalyst are sequentially filled from top to bottom. The activity of the hydrogenation treatment catalyst increases sequentially from top to bottom of the bed, and the activity of the lowest end catalyst is lower than that of the upper layer. Similarly, the activity of the medium oil type cracking catalyst increases sequentially from top to bottom of the bed, and the activity of the lowest end catalyst is lower than that of the upper layer.

[0022] Further, in the above technical solution, the operating conditions of the upper bed of the hydrogenation pretreatment reactor in step (1) are as follows: the average reaction temperature is 200-380℃, the reaction pressure is 8-20 MPa, the hydrogen oil volume ratio is 200:1-2500:1, the volume space velocity is 0.2-10.0 h -1 -1, and the top reflux ratio is 1.2-4.5. The preferred operating conditions are: the average reaction temperature is 260-360℃, the volume space velocity is 0.5-5.0 h -1 , the reaction pressure is 6-18 MPa, the hydrogen oil volume ratio is 400:1-1200:1, and the top reflux ratio is 1.5-3.0.

[0023] In the above technical solution, the operating conditions of the lower bed of the hydrogenation pretreatment reactor in step (1) are as follows: the average reaction temperature is 250-520℃, the reaction pressure is 8-20 MPa, the hydrogen oil volume ratio is 200:1-2500:1, and the volume space velocity is 0.2-10.0 h -1 . The preferred operating conditions are: the average reaction temperature is 300-400℃, the volume space velocity is 0.3-3.0 h -1 , the reaction pressure is 6-18 MPa, the hydrogen oil volume ratio is 500:1-1500:1.

[0024] Further, in the step (1), the temperature for the flash evaporation of the raw oil in the middle part of the hydrogenation pretreatment reactor is 300-450 DEG C, preferably 320-400 DEG C.

[0025] In the hydrogenation raw material, the existing forms of sulfides are mainly hydrogen sulfide, mercaptan, sulfide, disulfide, thiophene and other organic compounds. The hydrogen sulfide and mercaptan mainly exist in the distillate oil less than 300 DEG C, the sulfide and disulfide mainly exist in the middle distillate oil (200 DEG C-350 DEG C), and the sulfide, disulfide and thiophene exist in the distillate oil above 350 DEG C. In the present application, the sulfides in the wax oil are mainly sulfides and thiophenes, and the sulfides in the straight-run wax oil include chain sulfides and cyclic sulfides. The sulfides in the VGO are mainly cyclic sulfides. The thiophene sulfides are alkyl thiophene, alkyl benzothiophene, alkyl dibenzothiophene and the like. With the increase of the boiling point, the thiophene sulfur content first increases and then decreases, and the sulfides are concentrated in the fraction of 380 DEG C-530 DEG C. The monocyclic aromatic hydrocarbons (benzene, toluene, xylene, ethylbenzene, alkylbenzene and benzene-cycloalkane) are mainly concentrated in the fraction of the initial boiling point-290 DEG C, and the fractions above 290 DEG C are mainly bicyclic and tricyclic aromatic hydrocarbons. The distribution of nitrogen also has a similar distribution rule as the sulfides and aromatic hydrocarbons. In the distillate oil less than 320 DEG C, the nitrogen content accounts for about 25% of the total distillate oil, and the main nitrogen compounds are aniline and indole. In the distillate oil above 320 DEG C, the nitrogen content is mainly carbazole, which accounts for about 75% of the total distillate oil. The order of the hydrogenation denitrification from easy to difficult for the three types of nitrogen compounds is aniline>indole>carbazole.

[0026] Based on the above principle, the reactor of the present application is provided with internal components and process parameters are adjusted, and the temperature distribution can be from 200 DEG C to 520 DEG C at different reactor positions, so that different special catalysts can be placed at different reactor positions according to the temperature distribution, and the different forms of sulfur, nitrogen and aromatic hydrocarbons in the respective fractions are subjected to hydrogenation treatment, thereby improving the conversion efficiency and service life of the catalyst.

[0027] In the present application, the raw oil is subjected to flash evaporation under the conditions described in the present application, and under the action of hydrogen stripping, the distillate oil less than 300 DEG C is sent to the upper part of the hydrogenation pretreatment reactor. This part of the distillate oil mainly contains mercaptan sulfides, monocyclic aromatic hydrocarbons and aniline indole nitrogen compounds, and these components are relatively easy to remove, so the reaction can be carried out at a lower temperature, and the volume space velocity is also higher than that of the conventional hydrogenation refining reactor. After the light components are subjected to desulfurization and denitrification, there are still a small amount of monocyclic aromatic hydrocarbons and bicyclic aromatic hydrocarbons with long side chains and branched chains, and after passing through the cracking catalyst described in the present application, the side chains or branched chains can be opened, and the bicyclic rings can be opened, so that lighter monocyclic aromatic hydrocarbons are obtained, and the light aromatic hydrocarbon content of the light oil product is further improved, and the cracking depth is alleviated by controlling the volume space velocity and the reflux ratio at the top of the column.

[0028] In the present application, the heavy fraction greater than 300 DEG C enters the lower hydroprocessing catalyst bed, the lower bed controls lower volume space velocity and higher temperature, which can improve the removal rate of thiophene, carbazole and other impurities, and the middle oil type cracking catalyst placed in the lowermost part further improves the yield of middle distillate oil.

[0029] Further, in the above technical solution, the hydrogenation cracking reactor in step (2) is a middle feeding hydrogenation cracking reactor. The upper catalyst bed of the hydrogenation cracking reactor is provided with 1-3 layers, and the lower bed is provided with 2-8 layers, and each layer can be placed with catalysts of different activities and different volumes.

[0030] Further, the average activity and average pore size of the cracking catalyst in each bed of the upper part of the cracking reactor are smaller than the average activity and average pore size of the catalyst in each bed of the lower part of the cracking reactor.

[0031] Further, the catalytic activity of each bed in the lower part of the cracking reactor is preferably X1 < X2 < … < Xn (X represents activity, 1 … n represents the serial number of the catalyst bed), and the catalyst activity is defined as the conversion rate of the catalyst to the raw material; the pore size of each bed in the lower part is preferably d1 < d2 < … < dn.

[0032] Further, in the above technical solution, the hydroprocessing catalysts in steps (1) and (2) can be any suitable hydroprocessing catalysts, and preferably, the hydroprocessing catalysts have high desulfurization and denitrification activity and low aromatic saturation. The hydrogenation active component can be selected from one, two or more of metals in Group ⅥB and Group Ⅷ, such as W, Mo, Co and Ni, and the total content of the metal oxides is 5% to 75% by weight. The carrier of the hydrogenation catalyst can be selected from alumina, amorphous silica-alumina, silica oxide, titanium oxide and the like. A part of additives, such as P, Ti, Zr, Si, B and the like, can also be added to the catalyst. The hydroprocessing catalysts in the present application can be commercial catalysts, such as 3936, 3996, CH-20, FF-14, FF-16, FF-18, FF-24, FF-26, FF-34, FF-46, FF-56, FF-66, FH-UDS series, FZC-41, FZC-42 and the like developed by Fushun Petroleum Chemical Research Institute (FRIPP), HC-P, HC-T, HC-K UF-210 / 220 and the like developed by UOP Company, HR-406, HR-416, HR-448 and the like developed by IFP Company, ICR154, ICR174, ICR178, ICR179 and the like developed by CLG Company, TK-525, TK-555, TK-557 and the like developed by Topsoe Company, KF-752, KF-756, KF-757, KF-840, KF-848, KF-901, KF-907 and the like developed by AKZO Company, but are not limited to the above catalysts.

[0033] Further, in the above technical solution, the hydroprocessing catalysts in steps (1) and (2) can be any suitable hydroprocessing catalysts, and preferably, the hydroprocessing catalysts have high desulfurization and denitrification activity and low aromatic saturation. The hydrogenation active component can be selected from one, two or more of metals in Group ⅥB and Group Ⅷ, such as W, Mo, Co and Ni, and the total content of the metal oxides is 5% to 75% by weight. The carrier of the hydrogenation catalyst can be selected from alumina, amorphous silica-alumina, silica oxide, titanium oxide and the like. A part of additives, such as P, Ti, Zr, Si, B and the like, can also be added to the catalyst. The hydroprocessing catalysts in the present application can be commercial catalysts, such as 3936, 3996, CH-20, FF-14, FF-16, FF-18, FF-24, FF-26, FF-34, FF-46, FF-56, FF-66, FH-UDS series, FZC-41, FZC-42 and the like developed by Fushun Petroleum Chemical Research Institute (FRIPP), HC-P, HC-T, HC-K UF-210 / 220 and the like developed by UOP Company, HR-406, HR-416, HR-448 and the like developed by IFP Company, ICR154, ICR174, ICR178, ICR179 and the like developed by CLG Company, TK-525, TK-555, TK-557 and the like developed by Topsoe Company, KF-752, KF-756, KF-757, KF-840, KF-848, KF-901, KF-907 and the like developed by AKZO Company, but are not limited to the above catalysts. 2 / g, pore volume is 0.3 to 0.7 mL / g.

[0034] Further, in the above technical solution, the other hydrocracking catalysts used in steps (1) and (2) can be any suitable hydrocracking catalysts available, preferably the catalyst active component is one or more of Group VIB and / or Group VIII metals. The Group VIB metal is generally Mo and / or W, and the Group VIII metal is generally Co and / or Ni. The support component of the catalyst includes one or more of alumina, silica-containing alumina, and molecular sieve, preferably containing a molecular sieve, and the molecular sieve can be a Y-type molecular sieve. In a preferred embodiment, the catalyst contains 10-35 wt% of Group VIB metal as oxide, 3-15 wt% of Group VIII metal as oxide, 5-40 wt% of molecular sieve, 15-72 wt% of amorphous silica-alumina, and 10-67 wt% of alumina, based on the weight of the catalyst; the specific surface area of the catalyst is 100-650 m 2 / g, and the pore volume is 0.15-0.50 mL / g. The hydrocracking catalysts can be commercial catalysts, and the main commercial catalysts include 3963, FC-18, FC-32, FC-60, FC-70, FC-76, FC-80 catalysts developed by Fushun Petrochemical Research Institute, HDK786, HDK776, HDK766 catalysts of Axens Company, and HC215, HC-120, DHC-8, HC-150, HC-140, HC43LT, HC190, HC-185, HC-175, HC-24 catalysts of UOP Company.

[0035] Research shows that the gas-liquid film contact on the solid surface reduces the resistance of gas mass transfer to the surface of the solid catalyst, and the continuous removal of reaction products from the system makes the equilibrium reaction proceed to the right, greatly improving the reaction efficiency and speed. Using gas-liquid feed in bed layer counter-current contact, and using the different boiling points of various components in the product, the light distillate oil in the product is continuously separated from the reaction system, not only reducing the probability of light distillate oil continuing to be deeply cracked, but also facilitating the forward progress of the main reaction and reducing the difficulty of controlling the operation conditions and the progress of the reaction. At the same time, the counter-current contact reactor can continuously remove the reaction heat from the catalyst system, and can also prevent the bed temperature from rising sharply and the accumulation of by-products and other adverse factors.

[0036] Further, in the above technical solution, the shape of the catalyst in steps (1) and (2) can be one or a mixture of more than one of a conventional hydrocracking catalyst, a porous catalyst, and a special-shaped catalyst, and is preferably a porous catalyst, a special-shaped catalyst, or a mixed catalyst of the conventional catalyst and the porous catalyst or the special-shaped catalyst. The porous catalyst has a pore diameter of 1-50 mm, preferably 4-20 mm; the special-shaped catalyst has an average particle diameter of 2-50 mm, preferably 4-30 mm; the honeycomb catalyst has a pore diameter or a pore side length of 1-50 mm, preferably 3-15 mm; and the catalyst bed has a voidage of 15-85%, preferably 20-75%.

[0037] Further, in the above technical solution, the shape of the special-shaped catalyst is a honeycomb, a Bauer ring, a Raschig ring, a square saddle ring, a saddle, an open ring type, a half ring, a stepped ring, a double arc, a Hall ring, a conjugate ring, a flat ring, a garland, a hollow ball, a gear shape, a clover, or the like.

[0038] Further, in the above technical solution, the overhead distillate extraction temperature of the hydrogen pretreatment reactor and the hydrogen cracking reactor in steps (3) and (4) is 140-240°C, preferably 160-210°C.

[0039] Further, in the above technical solution, the hydrogen cracking reactor in step (2) has 1-2 side lines arranged at the top of the middle cavity. The first side line has an extraction temperature of 180-250°C, preferably 180-230°C, and the component extracted in the side line is a jet fuel fraction; and the second side line has a temperature of 160-380°C, preferably 180-360°C, and the component extracted in the side line is a diesel component.

[0040] Further, different catalysts having different functions can be arranged in the sub-beds from the raw oil inlet to the unconverted oil outlet. Preferably, the catalysts for the hydrogen cracking function have an average pore diameter that gradually increases.

[0041] Further, in the above technical solution, the raw inferior diesel and hydrogen in step (1) are heated by a heating furnace before entering the hydrogen treatment reaction zone, and are preferably heated to 200-350°C. The separation in step (1) is preferably performed in a gas-liquid separation tank, and the gas (containing hydrogen and non-condensable gas) is extracted from the top of the separation tank and is pressurized by a hydrogen compressor to enter the hydrogen treatment reaction zone as the circulating hydrogen.

[0042] Further, in the above technical solution, the gas stripping column in step (4) is of a conventional design in the art, and can be provided with a reboiler or steam stripping. The bottom temperature is generally 200-350°C, preferably 250-300°C. The condensation temperature at the top of the gas stripping column is generally 140-240°C, preferably 160-210°C.

[0043] Compared with the prior art, the present application has the following beneficial effects:

[0044] 1、The present application adopts the middle feeding mode of the reactor, under the action of the separation chamber, the light and heavy components in the raw oil enter the upper and lower parts of the reactor respectively, realizing the fraction oil screening of different raw oils in the reactor, the hydrogenation treatment or hydrocracking catalysts required are loaded in the upper and lower parts of the reaction zone, the depth of hydrogenation of the fraction oil is realized in the reactor by changing the operating conditions, the naphtha yield is finally improved, and the polycyclic aromatic hydrocarbons in the raw material are moderately opened on the different functional catalyst beds, and the content of light aromatics in the light oil is increased.

[0045] 2、The gas and liquid raw materials realize thin film reverse contact mass transfer reaction on the surface of the solid catalyst, the thickness of the traditional solid-liquid soaking mass transfer film is reduced, the mass transfer is strengthened, and the reaction speed is improved.

[0046] 3、In the present application, the light components and reaction heat generated by the reaction can be removed from the reaction bed at any time, which is especially suitable for improving the hydrogenation efficiency of hydrogenation exothermic and heat balance reaction, and the continuous removal of light components greatly improves the yield of the target product.

[0047] 4、In the present application, the reaction and separation are concentrated in one reactor, and different functional catalysts are also placed in the same reactor, compared with the traditional multi-reactor and multi-fractionating tower process, the high separator, low separator and supporting fractionating tower and other equipment can be saved, the process is short and easy to operate, and the land occupation and energy consumption are saved.

[0048] 5、Compared with the existing hydrocracking technology, the catalytic diesel oil of the present application can be blended with wax oil at any ratio, improving the flexibility of the device, under the same raw material and process conditions, the monocyclic aromatic hydrocarbon yield of the present application is 2-8 percentage points higher than that of the conventional fixed bed two-stage process. The naphtha fraction obtained by the present application is rich in aromatic hydrocarbons, which is a high-quality reformer raw material, and the unconverted oil obtained is a high-quality ethylene cracking material. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 It is a wax oil hydrogenation treatment method process schematic diagram of the present application;

[0050] Wherein: 1 - feed oil inlet; 2 - fresh hydrogen; 21, 22 - recycle hydrogen; 3 - hydrogen pretreatment reactor; 4 - pretreatment overhead condenser; 5 - pretreatment overhead separator; 6 - pretreatment product oil; 7 - hydrocracking feed oil; 8 - hydrocracking reactor; 9 - cracking overhead condenser; 10 - cracking overhead separator; 11 - cracking column bottom reboiler; 12 - unconverted oil; 13 - stripping column; 14 - stripping column overhead condenser; 15 - stripping column overhead separator; 16 - stripping column bottom reboiler; 17 - recycle oil; 18 - ethylene cracking feed; 19 - middle distillate oil; 20 - desulfurization and deamination equipment; 21 - recycle hydrogen compressor; 22, 23 - gas-liquid separation chamber; 24 - naphtha fraction. DETAILED DESCRIPTION

[0051] The specific embodiments of the present application will now be described in detail with reference to the accompanying drawings. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the application, are given by way of illustration only, since various changes and modifications within the spirit and scope of the application will become apparent to those skilled in the art from this detailed description.

[0052] Throughout the specification and claims, the term "comprising" or variations such as "comprise" or "comprises" will be understood to mean the inclusion of a stated element or group of elements but not the exclusion of any other element or group of elements.

[0053] In this document, relational terms such as "first," "second," and the like can be used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus. The terms "a" and "an" are defined as one or more unless explicitly indicated to the contrary or otherwise evident from the context. The terms "sub-portion" and "sub-portion of" as used herein refer to one or more parts of something.

[0054] In this document, the terms "first," "second," "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. In other words, unless explicitly stated otherwise, these terms are used in their "ordinal" sense and can be used interchangeably with "initial," "primary," "first," "principal," "leading," and the like.

[0055] Figure 1 The figure shows a schematic diagram of the wax oil hydrogenation process of the present application. The figure is combined with the description of the process. Figure 1The process of the present application comprises: the catalytic diesel blended waxy oil is heated to 200-380℃ and then enters the separation cavity 23 in the hydrogenation pretreatment reactor, in the separation cavity 23, the separation is into light components and heavy components. The light components pass through the hydrogenation treatment catalyst bed for desulfurization and denitrification and hydrogenation saturation, and then enter the pre-treatment overhead condenser 4 for cooling and then enter the liquid separator 5 for gas-liquid separation, the non-condensable gas rich in hydrogen passes through the desulfurization and denitrification device 20 and then returns to the bottom of the hydrogenation pretreatment tower as the device hydrogen 2-1 to enter the catalyst bed in the tower. The heavy components enter the hydrogenation treatment catalyst bed and the hydrogenation cracking catalyst bed in turn, and the hydrogen gas countercurrently upward from the bottom of the tower completes the reaction on the surface of the catalyst. The hydrogen sulfide, ammonia and light hydrocarbons generated in the hydrogenation process of the heavy components immediately enter the top of the reactor with the hydrogen, and do not continue to carry out hydrogenation reaction with the heavy components. The generated oil 6 after the hydrogenation pretreatment is mixed with the recycle oil 17 as the raw material oil 8 to enter the middle separation cavity 23 of the hydrogenation cracking reactor 8. Similarly, the light components separated in the separation cavity 23 enter the cracking catalyst bed upward, the selective ring-opening and saturation of the heavier components are carried out, and the lighter components pass through the bed to the overhead condenser 9 for cooling, and then enter the liquid separator 10 for gas-liquid separation, and then the light components enter the recycle hydrogen system. The liquid hydrocarbons after condensation are sent out as high-aromatic products 24. The heavy components separated in the separation cavity 23 enter the catalyst bed downward and contact the hydrogen 2-2 entering from the top of the reactor in a reverse film mode to carry out hydrogenation and cracking reactions, the light components generated in the reaction are separated from the catalyst bed upward and finally condensed as high-aromatic products 24, and the unconverted oil returns to the reactor inlet as the recycle oil 17 and can be sent out of the device as a chemical material 18.

[0056] The following examples further illustrate the waxy oil hydrogenation method and the effect of the present application. In the examples, the detailed implementation and specific operation process are given on the premise of the technical solution of the present application, but the protection scope of the present application is not limited to the specific examples described below, such as the repositioning of various types of protective agents in the hydrogenation pretreatment catalyst bed, which is also within the protection scope of the present application.

[0057] In the following examples, the experimental methods are conventional methods in the art unless otherwise specified. Example 1

[0058] Using the flowchart shown in the present application Figure 1 The raw material oil is a mixed oil of vacuum waxy oil and catalytic diesel, and the volume ratio of catalytic diesel is 27% (1# raw material oil). The raw material oil and hydrogen are heated to 400℃ by a heating furnace and then enter the separation cavity of the hydrogenation pretreatment reactor, the separation cavity accounts for 1% of the total effective volume of the reactor, the separation cavity is filled with stepped ring packing, 2 layers are placed in the upper part, and catalyst A and catalyst B are filled from bottom to top, V A :V B=2:1. The lower part is filled with 3 layers of catalysts, from top to bottom, catalyst A, catalyst A, and catalyst B, V A :V B =3:1. Hydrogen enters from the bottom of the reactor, passes through the lower catalyst bed, the upper catalyst bed, and finally reaches the top of the reactor with light components such as light hydrocarbons, hydrogen sulfide, and ammonia produced by hydrogenation. The heavy components after hydrogenation are separated from the bottom of the column and enter the separation chamber of the hydrocracking reactor, which accounts for 1.5% of the total effective volume of the reactor. The separated light components pass through the upper two cracking catalyst beds, with catalysts C and D being loaded in sequence. C :V D =1.5:1. The separated heavy components enter the catalyst C, catalyst C, and catalyst D catalyst beds in sequence, and the light hydrocarbons produced after the reaction leave the bed along with hydrogen and other light components separated from the upper part and the light components produced by the bed hydrogenation. The light components are separated into light oil products and non-condensable gas after condensation. The unconverted oil at the bottom of the hydrogenation cracking reactor enters the stripping column to remove the light components in the unconverted oil, and then is sent out as a chemical cracking material from the bottom of the stripping column. The light components at the top of the stripping column are separated into high-aryl light oil products and non-condensable gas after condensation. The non-condensable gas from the top of the hydrogen pretreatment reaction zone, the hydrogenation cracking reactor, and the stripping column is mixed and then used as recycled hydrogen after desulfurization and pressure increase. The condensed light oil products are sent out together as products. Example 2

[0059] The difference between this example and Example 1 is that the feedstock oil used is 2# feedstock oil (catalytic diesel volume ratio is 50%), and the upper bed of the hydrogen pretreatment reactor is set with two, with catalyst A, catalyst A, and catalyst C placed in sequence from the separation chamber upwards. The remaining conditions are the same as in Example 1. Example 3

[0060] The difference between this example and Example 1 is that the hydrogen pretreatment catalysts are all selected as A. The remaining conditions are the same as in Example 1. Example 4

[0061] The same as Example 1, the difference is that the catalysts in the hydrogenation cracking reactor are all selected as D. The remaining conditions are the same as in Example 1. Example 5

[0062] The same as Example 1, the difference is that the upper and lower catalysts in the hydrogenation cracking reactor use catalyst E, with a bed porosity of 30%.

[0063] The catalyst properties of the above examples and comparative examples are shown in Table 1, the properties of the feedstock oil are shown in Table 2, the process conditions are shown in Table 3, and the product distribution of the examples and comparative examples is shown in Table 4.

[0064] Comparative Example 1

[0065] The conventional two-stage hydrogenation method, i.e. refining + cracking method, was used. The feedstock and hydrogen flowed from top to bottom in the refining and cracking reactors. The cracked distillate oil was separated in a separation tower and then sent out as product. In the comparative example, the hydrogenation treatment reactor was filled with catalyst A and catalyst B in a volume ratio of 2.5:1, and the cracking reactor was filled with catalyst D and catalyst C from top to bottom. The equipment included hot high separation, cold high separation, cold low separation, gas stripping tower, fractionation tower and heating furnace before the fractionation tower. The hydrogenation product was separated in the fractionation tower to obtain light oil, and the tail oil at the bottom of the fractionation tower was sent out as chemical cracking raw material. The other process conditions were the same as in Example 1.

[0066] Table 1 Catalyst properties

[0067] Catalyst A Catalyst B Catalyst C Catalyst D Catalyst E Catalyst support shape Raschig rings Raschig rings Raschig rings Raschig rings Cylindrical rods Catalyst inner ring diameter, mm 2.5 2.5 3.0 3.0 — Catalyst size, mm 4.5 mm x 4.5 mm 4.5 mm x 4.5 mm 5 mm x 5 mm 5 mm x 5 mm φ 1.8 mm / 5-8 mm Bed voidage after packing, % 70 70 73 73 35 Metal content MoO3, wt% 23.9 WO 3， wt%]]> 21.9 15.3 20.5 15.1 NiO, wt% 4.1 5.8 6.5 7.3 6.4 Specific surface area, m 2 / g]] 310 410 690 681 420 Pore volume, ml / g 0.32 0.51 0.48 0.42 0.41 Average pore diameter, nm 9 9 6 8

[0068] Table 2 Properties of raw oil

[0069] Feed oil Vacuum gas oil Catalytic diesel Wax oil + 27% catalytic diesel Wax oil + 50% catalytic diesel Number 1# 2# Density (20°C), g / cm 3 ]] 0.918 0.949 0.924 0.935 Distillation range, °C 292～515 174～357 203～520 196～523 Aromatics, wt% 37.9 78.2 48.5 58.2 (S)% 2.6 1.1 2.18 1.78 w (N / μg·g -1 ]]> ​ 850 6100 2315 3200

[0070] Table 3 Process conditions of examples and comparative examples

[0071] Hydroprocessing pre-treatment reactor Reactor inlet temperature, °C 400 Upper bed average reaction temperature, °C 345 Lower bed average reaction temperature, °C 368 Reaction pressure, MPaG 14.0 Inlet volumetric hydrogen to oil ratio 800：1 volume space velocity, h -1 ]]> 1.0 Hydrocracking reactor Upper bed average reaction temperature, °C 365 Lower bed average reaction temperature, °C 395 Reaction pressure, MPaG 14.0 Inlet volumetric hydrogen to oil ratio 1200:1 volume space velocity, h -1 ]] 1.5

[0072] Table 4 Product distribution of examples and comparative examples

[0073]

[0074] As can be seen from the results in Table 4, in the method of the present application, the light and heavy fractions are separately introduced into different catalyst beds for hydrogenation treatment, which realizes the selection of raw material and the division of catalysts, and effectively improves the light oil yield. At the same time, the content of aromatic hydrocarbons in the light oil is greatly improved, and the light oil yield of <210°C is increased by 9.4 percentage points and the aromatic hydrocarbon yield is increased by 8 percentage points under the same raw material. Under the same cracking catalyst, the light oil yield is increased by 3.1 percentage points and the aromatic hydrocarbon yield is increased by 2.1 percentage points.

Claims

1. A method for hydroprocessing of wax oil, characterized in that, It comprises the following steps: (1) The wax oil and the blended catalytic diesel are heated and then enter the middle part of the hydrogenation pretreatment reactor, and a light-heavy separation cavity is arranged in the middle part of the hydrogenation pretreatment reactor; In the light-heavy separation cavity, after flashing, the light components enter the upper part of the hydrogenation refining catalyst, and the heavy components enter the lower part of the hydrogenation treatment catalyst; The hydrogen gas enters from the bottom of the hydrogenation pretreatment reactor, and is in film contact hydrogenation with the heavy components flowing downward in the middle part; The upper part of the hydrogenation pretreatment reactor is provided with more than 2 layers of catalysts, and the hydrogenation refining catalyst, the hydrogenation cracking catalyst are sequentially filled from bottom to top; the lower part of the hydrogenation pretreatment reactor is provided with at least 2 catalyst beds, and the hydrogenation treatment catalyst, the middle oil type cracking catalyst are sequentially filled from top to bottom; the activity of the hydrogenation treatment catalyst increases sequentially from top to bottom, and the activity of the lowest end hydrogenation treatment catalyst is lower than that of the upper bed; the activity of the middle oil type cracking catalyst increases sequentially from top to bottom, and the activity of the lowest end middle oil type cracking catalyst is lower than that of the upper bed; (2) In step (1), the heavy components after hydrogenation pretreatment enter the middle part of the hydrogenation cracking reactor, and a light-heavy separation cavity is arranged in the middle part of the hydrogenation cracking reactor; in the light-heavy separation cavity, after flashing, the light fraction enters the upper part of the cracking catalyst bed, and the heavy fraction enters the lower part of the cracking catalyst bed; wherein, the average pore size of the lower part cracking catalyst is 1-5 nm larger than that of the upper part cracking catalyst; The upper part of the hydrogenation cracking reactor is provided with 1-3 layers of catalyst beds, and the lower part is provided with 2-8 layers of catalyst beds, and different activity and volume of catalysts are arranged in each layer; the average activity of the cracking catalyst in each bed of the upper part of the hydrogenation cracking reactor is less than that of the catalyst in each bed of the lower part of the hydrogenation cracking reactor; (3) The light components upward in step (1) flow out from the top of the hydrogenation pretreatment reactor after hydrogenation pretreatment, and after condensation, high-aromatic naphtha products are obtained; (4) The heavy fraction in step (2) is opened and cracked into naphtha fraction, middle oil fraction and hydrogenation saturated unconverted oil under the action of the lower part cracking catalyst and hydrogen; (5) The naphtha fraction and the middle oil fraction obtained in step (4) flow out from the top of the hydrogenation cracking reactor together with hydrogen, and are condensed to obtain high-aromatic naphtha fraction; the middle oil fraction obtained in step (4) is cracked again when it flows upward through the cracking catalyst bed again to obtain naphtha fraction.

2. The wax oil hydroprocessing process according to claim 1, characterized in that, It further comprises step (6): the hydrogenation saturated unconverted oil obtained in step (4) is stripped in a stripping tower, and the heavy fraction is sent out as ethylene cracking material product or returned to the raw material inlet of the hydrogenation cracking reactor for cracking again, and the light fraction is condensed to obtain naphtha fraction oil product.

3. The wax oil hydroprocessing process according to claim 1, characterized in that, The wax oil is selected from at least one of straight-run wax oil, vacuum wax oil and coking wax oil.

4. The wax oil hydroprocessing process according to claim 1, characterized in that, In the hydrogenation pretreatment reactor and the hydrogenation cracking reactor, the volume V0 of the light-heavy separation cavity is 0.5%-30% of the effective volume V of the hydrogenation pretreatment reactor and the hydrogenation cracking reactor.

5. The wax oil hydroprocessing process according to claim 1, characterized in that, In the hydrogenation pretreatment reactor and the hydrogenation cracking reactor, the light-heavy separation cavity is a cavity or is provided with packing or trays.

6. The wax oil hydroprocessing process according to claim 1, characterized in that, The operating conditions of the upper bed of the hydro-pretreatment reactor are as follows: the average reaction temperature is 200-380℃, the reaction pressure is 8-20 MPa, the hydrogen / oil volume ratio is 200:1-2500:1, the volume space velocity is 0.2-10.0 h -1 -1, and the tower top reflux ratio is 1.2-4.

5.

7. The wax oil hydroprocessing process according to claim 1, characterized in that, The operating conditions of the lower bed of the hydro-pretreatment reactor are as follows: the average reaction temperature is 250-520°C, the reaction pressure is 8-20 MPa, the hydrogen / oil volume ratio is 200: 1-2500: 1, the volume space velocity is 0.2-10.0 h -1 .

8. The wax oil hydroprocessing process according to claim 1, characterized in that, The temperature of the wax oil and the blended catalytic diesel in the middle flash of the hydrogenation pretreatment reactor in step (1) is 300-450℃.

9. The wax oil hydroprocessing process according to claim 1, characterized in that, In step (2), 1-2 side lines are arranged at the top of the light-heavy separation cavity in the middle of the hydrogenation cracking reactor.

10. The wax oil hydroprocessing process according to claim 9, characterized in that, The temperature of the first side line is 180-250℃, and the component extracted in the side line is jet fuel fraction; the temperature of the second side line is 160-380℃, and the component extracted in the side line is diesel component.

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