Processing method for producing more chemical raw materials from vacuum residue

Abstract

The present invention discloses a method for processing vacuum residue to produce more chemical raw materials. The method comprises: mixing the vacuum residue raw material with hydrogen and entering an ebullated bed hydrogenation reaction zone for hydrothermal cracking, followed by separation and fractionation to obtain a gas fraction, light distillate oil, wax oil, and tail oil; the light distillate oil has an initial boiling point of 50°C to 80°C and a final boiling point of 280°C to 340°C; in the presence of hydrogen, the light distillate oil and hydrogen are mixed and sequentially introduced into a first hydrocracking reaction zone and a second hydrocracking reaction zone for reaction; the obtained second hydrocracking product is separated and fractionated to obtain gas, light naphtha, heavy naphtha, and tail oil; the tail oil is mixed with hydrogen and entered into a third hydrocracking reaction zone; the obtained third hydrocracking product is separated and fractionated to obtain gas, light naphtha, and heavy naphtha; the first hydrocracking back pressure is 0.5 to 5.0 MPa higher than the third hydrocracking reaction pressure. This method can significantly improve the yield and quality of chemical raw materials.

Description

Technical Field

[0001] The present invention belongs to the field of heavy oil processing, and specifically relates to a processing method combining ebullated bed hydrogenation and hydrocracking, in particular a processing method for producing high-quality chemical raw materials using inferior heavy oil as raw material. Background Art

[0002] In recent years, with the gradual decline in light crude oil resources and the continuous rise in its price, the global trend has shifted to processing low-quality heavy crude oil, which has abundant reserves, widespread availability, and low prices. Simultaneously, market demand for light oil products continues to increase, and environmental regulations on oil quality are becoming increasingly stringent. This situation has forced refineries to seriously address the global technical challenge of deep processing of low-quality heavy oil. Ebullating-bed residue hydrotreating technology can be used to process heavy crude oils with high sulfur, high carbon residue, and high metal content. It offers advantages such as uniform reactor temperature, long operating cycles, and flexible unit operation. It can address the problems of low space velocity, rapid catalyst deactivation, and large system pressure drop in fixed-bed residue hydrotreating units, offering significant advantages.

[0003] CN201580070326.4 discloses a method for preparing LPG and BTX, comprising: a) subjecting a mixed hydrocarbon stream to a first hydrocracking in the presence of a first hydrocracking catalyst to produce a first hydrocracked product stream; b) separating the first hydrocracked product stream to provide at least one light hydrocarbon stream comprising at least C2 and C3 hydrocarbons, an intermediate hydrocarbon stream consisting of C4 and / or C5 hydrocarbons, and a heavy hydrocarbon stream comprising at least C6+ hydrocarbons, and c) subjecting the heavy hydrocarbon stream to a second hydrocracking in the presence of a second hydrocracking catalyst to produce a second hydrocracked product stream comprising BTX, wherein the second hydrocracking is more severe than the first hydrocracking, d) wherein, in the presence of a C4 hydrocracking catalyst, at least a portion of the intermediate hydrocarbon stream is subjected to C4 hydrocracking to produce a C4 hydrocracking product stream, and the C4 hydrocracking is optimized for converting C4 hydrocarbons into C3 hydrocarbons.

[0004] CN201480037272.7 discloses a method for producing light olefin hydrocarbon compounds from hydrocarbon feedstocks, comprising the following steps: (a) feeding the hydrocarbon feedstock to a reaction zone for ring opening; (b) separating the reaction product produced by the reaction zone into an overhead stream and a side stream; (c) feeding the side stream from (b) to a gasoline hydrocracker (GHC) unit; (d) separating the reaction product of the GHC of step (c) into an overhead stream comprising hydrogen, methane, ethane and liquefied petroleum gas and a stream comprising aromatic hydrocarbon compounds and a small amount of hydrogen and non-aromatic hydrocarbon compounds; (e) feeding the overhead stream from the gasoline hydrocracker (GHC) unit to a steam cracker unit.

[0005] In summary, petroleum hydrocarbons have a complex composition, mainly including chain alkanes, cycloalkanes and aromatics, among which chain alkanes, especially small molecular chain alkanes, are high-quality ethylene raw materials, while cycloalkanes and aromatics are high-quality reforming feeds. Ebullated bed hydrogenation is to cause heavy raw materials to undergo hydrogen thermal cracking reaction in a hydrogen environment, following the free radical reaction mechanism. Its products have high content of normal hydrocarbons and cyclic hydrocarbons. The existing technology for hydrogenating distillate oil from ebullated bed residue oil cannot efficiently achieve the conversion effect of "olefins as appropriate, aromatics as appropriate". Therefore, it is of great significance to develop a processing method suitable for producing high-quality chemical raw materials from inferior heavy oil as raw material through ebullated bed hydrogenation and hydrocracking. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a processing method for vacuum residue oil to produce more chemical raw materials. This method uses inferior heavy oil such as vacuum residue oil as raw material and can greatly improve the yield and quality of chemical raw materials.

[0007] The present invention provides a method for processing vacuum residue to produce more chemical raw materials, the method comprising:

[0008] (1) Vacuum residue oil feedstock is mixed with hydrogen and enters an ebullated bed hydrogenation reaction zone for hydrothermal cracking reaction, and gas fraction, light distillate oil, wax oil and tail oil are obtained through separation and fractionation; wherein the light distillate oil has an initial boiling point of 50°C to 80°C and a final boiling point of 280°C to 340°C;

[0009] (2) In the presence of hydrogen, the light distillate oil obtained in step (1) is mixed with hydrogen and enters the first hydrocracking reaction zone for the first hydrocracking, and the C7 + The mass content of normal alkanes is 0.1% to 5.0%;

[0010] (3) The reaction effluent of step (2) enters the second hydrocracking reaction zone, and selective ring-opening cracking is performed on bicyclic or higher cyclic hydrocarbons to obtain a second hydrocracking product; the second hydrocracking product is subjected to gas-liquid separation in a separator to obtain hydrogen-rich gas used as circulating hydrogen, and the liquid phase enters the fractionation system for fractionation to obtain gas, light naphtha, heavy naphtha and tail oil;

[0011] (4) The tail oil in step (3) is mixed with hydrogen and enters a third hydrocracking reaction zone to obtain a third hydrocracking product containing monocyclic hydrocarbons. The third hydrocracking product enters a separation and fractionation system to obtain gas, light naphtha, and heavy naphtha;

[0012] The reaction pressure of the first hydrocracking reaction zone in step (2) is 0.5 to 5.0 MPa higher than the reaction pressure of the third hydrocracking reaction zone in step (4).

[0013] According to the present invention, the properties of the vacuum residue in step (1) are as follows: an initial boiling point of 420° C. to 620° C., preferably 450° C. to 550° C.; a sulfur content by mass of 2% to 10%, preferably 4% to 8%; a nitrogen content by mass of 0.2% to 1.0%, preferably 0.3% to 0.5%; and a metal content of 100 mg / kg to 500 mg / kg, preferably 200 mg / kg to 300 mg / kg.

[0014] According to the present invention, the reaction conditions of the ebullated bed hydrogenation reaction zone in step (1) are as follows: reaction pressure of 10MPa to 25MPa, preferably 15MPa to 20MPa; reaction temperature of 350°C to 500°C, preferably 400°C to 450°C; hydrogen to oil volume ratio of 100:1 to 2000:1, preferably 300:1 to 1000:1; volume space velocity of 0.1h -1 ~1.5h -1 , preferably 0.2h -1 ~1.0h -1 .

[0015] According to the present invention, the conversion rate of the vacuum residue in the ebullated bed hydrogenation reaction zone in step (1) is controlled to be 60% to 90%, preferably 70% to 80%. The conversion rate is defined as the sum of the mass percentages of the gas fraction, light distillate oil and wax oil in the ebullated bed hydrogenation product relative to the fresh raw material.

[0016] According to the present invention, the light distillate oil in step (1) has an initial boiling point of 60°C to 70°C and a final boiling point of 290°C to 320°C.

[0017] According to the present invention, preferably, the C7 + The mass content of normal alkanes is 1.0% to 3.0%.

[0018] According to the present invention, the chemical raw materials mainly include ethane, propane, butane, light naphtha, and may also include heavy naphtha. Among them, heavy naphtha is used as a reforming feedstock to produce BTX, and ethane, propane, butane, and light naphtha are used as feedstocks for producing light olefins, such as steam cracking feedstocks to produce ethylene. Propane and butane can also be directly dehydrogenated to produce propylene and butene. Among them, light olefins refer to olefins with a carbon content of less than 4, especially ethylene, propylene, and butadiene.

[0019] According to the present invention, preferably, the reaction pressure of the first hydrocracking reaction zone in step (2) is 0.5 to 4.0 MPa higher than the reaction pressure of the third hydrocracking reaction zone in step (4).

[0020] According to the present invention, the reaction conditions of the first hydrocracking reaction zone in step (2) are as follows: the reaction pressure is 6 to 10 MPa, preferably 7 to 9 MPa.

[0021] According to the present invention, the reaction conditions of the first hydrocracking reaction zone in step (2) are as follows: the average reaction temperature is 250-450°C, preferably 300-400°C; the liquid hourly volume space velocity is 0.1-15.0h -1 , preferably 1.0~5.0h -1 ; The volume ratio of hydrogen to oil is 100:1 to 2500:1, preferably 400:1 to 2000:1.

[0022] According to the present invention, in step (2), the light distillate oil may contain impurities such as sulfur and nitrogen. As needed, a hydrorefining catalyst may be provided upstream of the first hydrocracking catalyst to remove impurities such as sulfur and nitrogen. The nitrogen content in the reactant stream in contact with the first hydrocracking catalyst is preferably less than 50 mg / kg, more preferably less than 20 mg / kg.

[0023] According to the present invention, in step (2), the first hydrocracking reaction zone is loaded with a first hydrocracking catalyst. The first hydrocracking catalyst can be one or more catalysts.

[0024] According to the present invention, in step (2), a conventional hydrorefining catalyst can be used as the hydrorefining catalyst provided upstream of the first hydrocracking catalyst, and is mainly used for hydrodesulfurization, nitrogen and other impurities. The hydrorefining catalyst comprises a carrier and a hydrogenation-active metal, wherein the carrier is an inorganic refractory oxide, generally selected from one or more of alumina, amorphous silica-alumina, silica or titanium oxide; and the hydrogenation-active metal comprises a metal component of Group VIB and / or Group VIII. In the hydrorefining catalyst, Group VIB is preferably selected from tungsten and / or molybdenum, and its content in the catalyst is 5% to 30% by weight of oxide, preferably 10% to 20% by weight; Group VIII is preferably selected from nickel and / or cobalt, and its content in the catalyst is 1% to 6% by weight of oxide, preferably 1.5% to 5% by weight. The content of the carrier in the catalyst is 64% to 94% by weight of oxide, preferably 75% to 88.5%.

[0025] According to the present invention, in step (2), the first hydrocracking catalyst comprises an active metal component and a support; the support comprises a molecular sieve having the ability to selectively crack normal alkanes, preferably one or more selected from ZSM-5 molecular sieve, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, and ZSM-38 molecular sieves, preferably ZSM-5 molecular sieve. The ZSM-5 molecular sieve has a SiO2 / Al2O3 molar ratio of 20 to 60. The support may further comprise a binder. Preferably, the binder is alumina. The active metal component comprises at least one of a metal from Group VIB and a metal from Group VIII, the metal from Group VIB preferably being molybdenum and / or tungsten, and the metal from Group VIII preferably being cobalt and / or nickel.

[0026] According to the present invention, in step (2), preferably, the first hydrocracking catalyst has, based on the weight of the catalyst, a content of Group VIB metal (calculated as oxide) of 5.0% to 15.0%, a content of Group VIII metal (calculated as oxide) of 2.0% to 5.0%, and a content of the carrier of 80.0% to 93.0%.

[0027] According to the present invention, in step (2), preferably, in the carrier of the first hydrocracking catalyst, the content of the binder is 8% to 60%, and the content of the molecular sieve is 40% to 92%, based on the weight of the carrier.

[0028] According to the present invention, in step (2), the specific surface area of ​​the first hydrocracking catalyst is 200 to 400 m 2 / g, and the pore volume is 0.25~0.45mL / g.

[0029] According to the present invention, the preparation method of the first hydrocracking catalyst in step (2) can be prepared according to conventional methods in the art. The preparation method includes preparing a carrier and loading the active metal component, wherein the carrier preparation process is as follows: mechanically mixing the shape-selective cracking molecular sieve and the binder, forming, and then drying and calcining to form a catalyst carrier. The drying and calcining of the carrier can adopt conventional conditions. The drying conditions are: drying at 100°C to 150°C for 1 to 12 hours. The calcining conditions are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0030] According to the present invention, in step (2), in the preparation method of the first hydrocracking catalyst, the method for loading the active metal component is a conventional method, such as a kneading method, an impregnation method, etc., preferably an impregnation method. The impregnation method can be a saturation impregnation method, an excess impregnation method, or a complex impregnation method, that is, the catalyst support is impregnated with a solution containing the desired active component, and then dried and calcined to obtain the first hydrocracking catalyst. The drying conditions are: drying at 100°C to 150°C for 1 to 12 hours. The calcination conditions are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0031] According to the present invention, the separation and fractionation of the second hydrocracking product of step (3) and the third hydrocracking product of step (4) preferably share a set of separation and fractionation systems.

[0032] According to the present invention, in step (3), the reaction conditions of the second hydrocracking reaction zone are as follows: the reaction pressure is 6 to 10 MPa, preferably 7 to 9 MPa.

[0033] According to the present invention, the reaction conditions of the second hydrocracking reaction in step (3) are as follows: the average reaction temperature is 250-450°C, preferably 300-400°C; the liquid hourly volume space velocity is 0.1-15.0h -1 , preferably 1.0~5.0h -1 ; The volume ratio of hydrogen to oil is 100:1 to 2500:1, preferably 400:1 to 2000:1.

[0034] According to the present invention, preferably, the first hydrocracking reaction zone and the second hydrocracking reaction zone adopt the same reaction pressure.

[0035] According to the present invention, in step (3), the second hydrocracking reaction zone is loaded with a second hydrocracking catalyst. The second hydrocracking catalyst can be one or more catalysts.

[0036] According to the present invention, the third hydrocracking reaction zone in step (4) is loaded with a third hydrocracking catalyst. The third hydrocracking catalyst can be one or more catalysts.

[0037] According to the present invention, the second hydrocracking catalyst in step (3) has the function of ring-opening cracking of polycyclic cyclic hydrocarbons.

[0038] According to the present invention, the third hydrocracking catalyst in step (4) has the function of selectively cracking the side chains of isomeric hydrocarbons or cyclic hydrocarbons and retaining monocyclic cyclic hydrocarbons.

[0039] According to the present invention, the second hydrocracking catalyst in step (3) and / or the third hydrocracking catalyst in step (4) comprise a cracking component, a hydrogenation component, and a binder. The second hydrocracking catalyst and / or the third hydrocracking catalyst can be commercially available or prepared according to existing technologies. The hydrogenation component is at least one of a metal, a metal oxide, and a metal sulfide of an active metal component; the active metal component comprises a VIB and / or VIII Group metal; and the active metal component is more preferably at least one of iron, chromium, molybdenum, tungsten, cobalt, and nickel. The binder is alumina and / or silica; and the cracking component comprises an acidic molecular sieve, preferably at least one of a Beta molecular sieve and a Y molecular sieve.

[0040] According to the present invention, it is further preferred that the cracking component of the second hydrocracking catalyst in step (3) is a Y molecular sieve.

[0041] According to the present invention, it is further preferred that the cracking component of the third hydrocracking catalyst in step (4) is Beta molecular sieve.

[0042] According to the present invention, in the second hydrocracking catalyst in step (3) and / or the third hydrocracking catalyst in step (4), based on the mass of the catalyst, the content of the hydrogenation component in terms of oxides is 5 wt% to 40 wt%, preferably 10 wt% to 30 wt%; the content of the cracking component is 10 wt% to 80 wt%, preferably 20 wt% to 60 wt%; and the content of the binder is 5 wt% to 85 wt%, preferably 10 wt% to 50 wt%.

[0043] According to the present invention, the preparation method of the second hydrocracking catalyst in step (3) and / or the third hydrocracking catalyst in step (4) can be prepared according to conventional methods in the art. The preparation method includes the preparation of a carrier and the loading of the hydrogenation component, wherein the preparation process of the carrier is as follows: the cracking component and the binder are mechanically mixed, formed, and then dried and calcined to form a catalyst carrier. The drying and calcination of the carrier can adopt conventional conditions. The drying conditions are: drying at 100°C to 150°C for 1 to 12 hours. The calcination conditions are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0044] According to the present invention, in the preparation method of the second hydrocracking catalyst in step (3) and / or the third hydrocracking catalyst in step (4), the method for loading the hydrogenation component is a conventional method, such as a kneading method, an impregnation method, etc., preferably an impregnation method. The impregnation method can be a saturation impregnation method, an excess impregnation method, or a complex impregnation method, that is, the catalyst support is impregnated with a solution containing the desired hydrogenation component, and then dried and calcined to obtain the hydrocracking catalyst. The drying conditions are: drying at 100°C to 150°C for 1 to 12 hours. The calcination conditions are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0045] According to the present invention, in the third hydrocracking product of step (4), the ratio of the mass of C6-C8 monocyclic cyclic hydrocarbons to the mass of the total cyclic hydrocarbons in the light distillate oil feedstock is 0.35-0.55, preferably 0.44-0.50.

[0046] According to the present invention, the reaction conditions of the third hydrocracking reaction zone in step (4) are as follows: the reaction pressure is 3 to 7 MPa, preferably 4 to 6 MPa.

[0047] According to the present invention, the reaction conditions of the third hydrocracking reaction zone in step (4) are as follows: the average reaction temperature is 250-450°C, preferably 300-400°C; the liquid hourly volume space velocity is 0.1-15.0h -1 , preferably 1.0~5.0h -1 ; The volume ratio of hydrogen to oil is 100:1 to 2500:1, preferably 400:1 to 2000:1.

[0048] Petroleum hydrocarbons are complex, primarily comprising alkanes, cycloalkanes, and aromatics. High-quality ethylene feedstocks are small-molecule normal alkanes, while reforming feedstocks are monocyclic cycloalkanes and aromatics. The inventors have discovered that diesel feedstocks can be processed sequentially through shape-selective cracking of linear alkanes, ring-opening cracking of polycyclic cyclic hydrocarbons, and selective hydrocracking of long side chains on isomeric or cyclic hydrocarbons, thereby retaining as many monocyclic cyclic hydrocarbons as possible. This allows for the highly selective production of small-molecule normal alkanes in light olefin feedstocks, while simultaneously retaining as many monocyclic cyclic hydrocarbons as possible in heavy naphtha, thereby achieving efficient enrichment of high-quality reforming feedstocks. This significantly improves the yield of chemical feedstocks (i.e., light olefin feedstocks and reforming feedstocks) and their quality, leading to the completion of the present invention.

[0049] Compared with the prior art, the present invention has the following beneficial technical effects:

[0050] (1) In the prior art, when ebullated bed diesel is used as a raw material for hydrocracking to produce chemical raw materials, the final boiling point of the ebullated bed diesel obtained by fractionation of the ebullated bed fraction is generally 350-380°C, which also makes the content of tricyclic aromatics in the ebullated bed diesel fraction high. A higher reaction pressure is required to achieve hydrocracking of tricyclic aromatics. The higher reaction pressure will also cause some monocyclic aromatics to undergo ring-opening cracking during the hydrocracking process, resulting in loss of aromatics. In the processing method of vacuum residue oil for producing more chemical raw materials of the present invention, after the ebullated bed fraction oil enters the fractionating tower, the tricyclic aromatics content of the fractionating tower top oil (light distillate oil) is controlled to be no more than 1%, and an appropriate reaction pressure is selected to achieve mixed processing of monocyclic aromatics and bicyclic aromatics, thereby reducing the loss of aromatics in the raw material during the hydrogenation process and increasing the aromatics content in the hydrogenated product. Specifically, the ebullated bed hydrogenated light distillate oil and hydrogen enter the first hydrocracking reaction zone, which mainly selectively cracks the normal alkanes and the long straight-chain isoalkanes and cycloalkanes in the feedstock to produce small molecular normal alkanes, so that the C7 + The content of normal alkanes is between 0.1% and 5.0%. The effluent from the first hydrocracking reaction enters the second hydrocracking reaction zone, which mainly performs ring-opening cracking of polycyclic cyclic hydrocarbons while retaining monocyclic cyclic hydrocarbons, and further breaks the side chains of each hydrocarbon to generate small-molecule hydrocarbons. In this way, a large amount of chain alkanes in the feedstock can be converted into gas and light naphtha components, that is, enriched in the ethylene feedstock, while monocyclic cyclic hydrocarbons are retained in the heavy naphtha fraction, that is, enriched in the reforming feedstock. Through simple fractional distillation, efficient separation of chain alkanes and cyclic hydrocarbons can be achieved, thereby increasing the production of high-quality ethylene cracking feed and improving the quality of heavy naphtha as catalytic reforming feed.

[0051] (2) The heavy naphtha obtained by the method of the present invention has a high content of monocyclic cyclic hydrocarbons. When used as feed for a catalytic reforming unit, the cyclization and dehydrogenation units of the paraffins in the catalytic reforming unit can be eliminated, thereby significantly reducing the investment and energy consumption of the catalytic reforming unit. At the same time, since the hydrocracking reaction follows the positive carbon ion reaction mechanism, the cyclic hydrocarbons above C9 can be selectively subjected to side chain scission reactions, so that the C6-C8 cyclic hydrocarbons in the product have a high enrichment degree. After catalytic reforming and aromatics extraction, the BTX yield can be significantly increased.

[0052] (3) The present invention selectively converts the chain alkanes in the light distillate oil into small molecular alkanes. This process consumes a certain amount of hydrogen, but the light hydrocarbons as raw materials for the ethylene plant also have a high hydrogen yield. The lower the carbon number, the higher the hydrogen yield. Therefore, most of the hydrogen consumed in the hydrogenation process can be recovered after passing through the ethylene plant. At the same time, light hydrocarbons as ethylene raw materials can greatly increase the yields of ethylene, propylene and butadiene, and extend the rubber cleaning cycle of the ethylene plant, significantly improving the economic benefits of the plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a process flow diagram of the process method of the present invention;

[0054] Description of main reference numerals:

[0055] 1-heavy oil feedstock, 2-hydrogen, 3-ebullated bed hydrogenation reaction zone, 4-ebullated bed hydrogenation reaction effluent, 5-separator, 6-gas stream, 7-liquid stream, 8-fractionation tower, 9-gas fraction, 10-light distillate oil, 11-wax oil, 12-tail oil, 13-hydrogen, 14-first hydrocracking reaction zone, 15-first hydrocracking reaction effluent, 16-second hydrocracking reaction zone, 17-second hydrocracking reaction effluent, 18-separator, 19-gas stream hydrogen-rich gas, 20-liquid stream, 21-fractionation tower, 22-gas fraction, 23-light naphtha, 24-heavy naphtha, 25-tail oil, 26-third hydrocracking reaction zone, 27-third hydrocracking reaction zone effluent. DETAILED DESCRIPTION

[0056] The effects and benefits of the present invention are further illustrated below by way of examples, but the following examples do not constitute a limitation to the method of the present invention.

[0057] In the present invention, unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless the weight basis does not conform to the general understanding of those skilled in the art.

[0058] In the present invention, the total volume space velocity in the examples and comparative examples is the ratio of the volume of fresh feed to the total volume of the catalyst.

[0059] In the present invention, Figure 1 As shown, the process comprises: a heavy oil feedstock 1 is mixed with hydrogen 2 and enters an ebullated bed hydrogenation reaction zone 3; the obtained ebullated bed hydrogenation reaction effluent 4 enters a separator 5; the separated gas phase stream 6 is recycled; the liquid phase stream 7 enters a fractionation tower 8, and fractionation obtains a gas fraction 9, a light distillate oil 10, a wax oil 11 and a tail oil 12; the light distillate oil 10 is mixed with hydrogen 13 and enters a first hydrocracking reaction zone 14 for a hydrocracking reaction; the first hydrocracking reaction effluent 1 5 enters the second hydrocracking reaction zone 16, the second hydrocracking reaction effluent 17 enters the separator 18, the separated gaseous stream hydrogen-rich gas 19 is recycled, the liquid stream 20 enters the fractionation tower 21, and is fractionated to obtain a gas fraction 22, light naphtha 23, heavy naphtha 24 and tail oil 25. The tail oil 25 is mixed with hydrogen 13 and enters the third hydrocracking reaction zone 26. The third hydrocracking reaction effluent 27 enters the separator 18 for separation and fractionation.

[0060] In the present invention, the first hydrocracking catalyst in each example is represented by Cat-A plus a number, such as Cat-A1, Cat-A2, Cat-A3, and Cat-A4. The first hydrocracking catalyst is prepared by a conventional active metal saturation impregnation method. The physicochemical properties of the obtained catalyst are shown in Table 1.

[0061] In the present invention, the second hydrocracking catalyst in each example is represented by Cat-B, and the physicochemical properties of the catalyst are shown in Table 2.

[0062] In the present invention, the third hydrocracking catalyst in each example is represented by Cat-C, and the physicochemical properties of the catalyst are shown in Table 2.

[0063] In the present invention, the second hydrocracking catalyst and the third hydrocracking catalyst in each example are prepared by a conventional active metal saturation impregnation method.

[0064] The properties of the Beta molecular sieve used in the catalyst Cat-C are as follows: SiO2 / Al2O3 molar ratio is 30, specific surface area is 350m 2 / g, pore volume is 0.32cm 3 / g. The properties of the Y molecular sieve used in the catalyst Cat-B are as follows: SiO2 / Al2O3 molar ratio is 15, specific surface area is 400m 2 / g, pore volume is 0.30cm 3 / g, and the physicochemical properties of the obtained catalyst are shown in Table 2.

[0065] In the present invention, the raw oil in each example is vacuum residue raw material, and its main properties are shown in Table 3.

[0066] In the present invention, the nitrogen content in the reactant stream contacting the first hydrocracking catalyst in step (2) in each example is less than 20 mg / kg.

[0067] In the present invention, the ethylene raw materials in each example refer to the ethane, propane, butane and light naphtha obtained in step (3). Ethane, propane, butane and light naphtha can be directly used as raw materials for steam cracking to produce ethylene.

[0068] In the present invention, the distillation range of light naphtha is a liquid component less than 60°C, and the distillation range of heavy naphtha is 60-175°C.

[0069] In the present invention, the yield of ethylene feedstock refers to the mass ratio of ethane, propane, butane and light naphtha in the hydrocracking product to the fresh hydrocracking feedstock (light distillate oil), and the yield of heavy naphtha refers to the mass ratio of heavy naphtha in the hydrocracking product to the fresh hydrocracking feedstock (light distillate oil).

[0070] Examples 1 to 4

[0071] The processing method of vacuum residue oil to produce chemical raw materials adopts the following method: Figure 1 Process, including:

[0072] (1) The vacuum residue oil feedstock is mixed with hydrogen and enters the ebullated bed hydrogenation reaction zone for hydrothermal cracking reaction. The resulting ebullated bed hydrogenation reaction effluent enters a separator, the separated gaseous phase stream is recycled, and the liquid phase stream enters a fractionation tower for fractionation to obtain a gas fraction, light distillate oil, wax oil, and tail oil;

[0073] (2) The light distillate oil is mixed with hydrogen and enters the first hydrocracking reaction zone; the first hydrocracking reaction zone is filled with a first hydrocracking catalyst; in step (2), the C7 + n-Alkanes content.

[0074] (3) The first hydrocracking reaction effluent obtained in step (2) enters a second hydrocracking reaction zone, which is loaded with a second hydrocracking catalyst; a reaction is carried out under the action of the catalyst to obtain a second hydrocracking product. The hydrogen-rich gas obtained after separation and fractionation of the second hydrocracking product is used as circulating hydrogen, and the liquid phase enters a fractionation tower for fractionation to obtain gas, light naphtha, heavy naphtha, and tail oil;

[0075] (4) The tail oil of step (3) enters the third hydrocracking reaction zone, and the third hydrocracking reaction zone is loaded with a third hydrocracking catalyst; the third hydrocracking reaction effluent and the second hydrocracking reaction effluent share a set of separation and fractionation systems.

[0076] The process conditions and hydrogenation effects of each case are shown in Table 5.

[0077] Comparative Example 1

[0078] The difference from Example 1 is that the ebullated bed light distillate oil directly enters the second hydrocracking reaction zone without the first hydrocracking.

[0079] The process conditions and hydrogenation effects in this example are shown in Table 5.

[0080] Comparative Example 2

[0081] The difference from Example 1 is that in step (1), the C7 + The normal alkane content is 6%.

[0082] The process conditions and hydrogenation effects in this example are shown in Table 5.

[0083] Comparative Example 3

[0084] The difference from Example 1 is that the catalysts in the second and third hydrocracking reaction zones were exchanged. Specifically, the second hydrocracking reaction zone was filled with catalyst Cat-C, and the third hydrocracking reaction zone was filled with catalyst Cat-B.

[0085] The process conditions and hydrogenation effects in this example are shown in Table 5.

[0086] Comparative Example 4

[0087] The difference from Example 1 is that the reaction pressure of the first hydrocracking reaction zone is the same as the reaction pressure of the third hydrocracking reaction zone.

[0088] The process conditions and hydrogenation effects in this example are shown in Table 5.

[0089] Comparative Example 5

[0090] The difference from Example 1 is that the mass content of tricyclic aromatic hydrocarbons in the ebullated bed light distillate oil is 3.5%.

[0091] The process conditions and hydrogenation effects in this example are shown in Table 5.

[0092] Table 1 Physicochemical properties of the first hydrocracking catalyst

[0093] catalyst Cat-A1 Cat-A2 Cat-A3 Cat-A4 <![CDATA[Pore volume, cm 3 / g]]> 0.35 0.45 0.25 0.30 <![CDATA[Specific surface area, m 2 / g]]> 300 200 400 350 Content, wt%, based on the weight of the carrier ZSM-5 58 42 85 75 Alumina 42 58 15 25 Active metal content in catalyst, wt% <![CDATA[MoO3]]> 10.0 15.0 5.0 12.5 NiO 3.5 2.0 5.0 4.0 <![CDATA[SiO2 / Al2O3 molar ratio of ZSM-5]]> 40 60 20 50

[0094] Table 2 Physicochemical properties of the second hydrocracking catalyst and the third hydrocracking catalyst

[0095] Catalyst properties Cat-C Cat-B <![CDATA[Pore volume, cm 3 / g]]> 0.35 0.35 <![CDATA[Specific surface area, m 2 / g]]> 300 300 Catalyst composition and content Beta, wt% 50 - Y, wt% - 30 <![CDATA[MoO3,wt%]]> 10 20 NiO, wt% 5 5 Alumina, wt% 35 45

[0096] Table 3 Main properties of raw materials

[0097] Raw oil name Vacuum residue <![CDATA[Density (20 °C) / kg·m -3 > 1.032 Distillation range / ℃ IBP / 10% 464 / 558 30％ / 50％ 606 / 646 70％ / 90％ 749 / 973 95% / EBP 1025 / 1055 Sulfur content, wt% 5.61 Nitrogen content, wt% 0.38 Ni+V, mg / kg 200

[0098] Table 4 Ebullated bed hydrogenation process conditions and main properties of ebullated bed light distillate oil

[0099]

[0100]

[0101] Table 4

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[0103] Table 5 Hydrogenation effect

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[0105]

[0106] Table 5

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[0108]

[0109] The above describes in detail the specific embodiments of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as the contents disclosed by the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for processing vacuum residue to produce more chemical raw materials, the method comprising: (1) The vacuum residue oil feedstock is mixed with hydrogen and enters the ebullated bed hydrogenation reaction zone for hydrothermal cracking reaction, and the gas fraction, light distillate oil, wax oil and tail oil are obtained through separation and fractionation; wherein the light distillate oil has an initial boiling point of 50°C to 80°C and a final boiling point of 280°C to 340°C; (2) In the presence of hydrogen, the light distillate oil obtained in step (1) is mixed with hydrogen and enters the first hydrocracking reaction zone for the first hydrocracking, and the C7 + The mass content of normal alkanes is 0.1%~5.0%; (3) The reaction effluent from step (2) enters the second hydrocracking reaction zone, where the bicyclic or higher cyclic hydrocarbons are subjected to selective ring-opening cracking to obtain a second hydrocracking product; the second hydrocracking product is subjected to gas-liquid separation in a separator to obtain hydrogen-rich gas which is used as circulating hydrogen, and the liquid phase enters the fractionation system for fractionation to obtain gas, light naphtha, heavy naphtha and tail oil; (4) The tail oil in step (3) is mixed with hydrogen and enters the third hydrocracking reaction zone to obtain a third hydrocracking product containing monocyclic hydrocarbons. The third hydrocracking product enters the separation and fractionation system to obtain gas, light naphtha, and heavy naphtha; Wherein, the reaction pressure of the first hydrocracking reaction zone in step (2) is 0.5-5.0 MPa higher than the reaction pressure of the third hydrocracking reaction zone in step (4); In step (1), the mass content of tricyclic aromatic hydrocarbons in the light distillate oil is not higher than 1.0%; In step (2), the first hydrocracking reaction zone is loaded with a first hydrocracking catalyst; the first hydrocracking catalyst comprises an active metal component and a carrier; the carrier comprises a molecular sieve having the ability to selectively crack normal alkanes, the molecular sieve being selected from one or more of ZSM-5 molecular sieve, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35 and ZSM-38 molecular sieves; the active metal component comprises at least one of a Group VIB metal and a Group VIII metal; In step (2), the first hydrocracking catalyst has a content of 5.0% to 15.0% of Group VIB metal in terms of oxide, 2.0% to 5.0% of Group VIII metal in terms of oxide, and 80.0% to 93.0% of the carrier, based on the weight of the catalyst; the carrier of the first hydrocracking catalyst has a content of 8% to 60% of the binder and a content of 40% to 92% of the molecular sieve, based on the weight of the carrier; In step (3), the second hydrocracking reaction zone is loaded with a second hydrocracking catalyst; In step (4), the third hydrocracking reaction zone is loaded with a third hydrocracking catalyst; The second hydrocracking catalyst in step (3) and the third hydrocracking catalyst in step (4) comprise a cracking component, a hydrogenation component and a binder; In step (3), the second hydrocracking catalyst cracking component is Y molecular sieve; In step (4), the cracking component of the third hydrocracking catalyst is Beta molecular sieve; In the second hydrocracking catalyst in step (3) and the third hydrocracking catalyst in step (4), based on the mass of the catalyst, the content of the hydrogenation component in terms of oxide is 5 wt% to 40 wt%; the content of the cracking component is 10 wt% to 80 wt%; and the content of the binder is 5 wt% to 85 wt%; The chemical raw materials include ethane, propane, butane, light naphtha and heavy naphtha, wherein heavy naphtha is used as a reforming raw material to produce BTX, and ethane, propane, butane and light naphtha are used as raw materials to produce low-carbon olefins.

2. The method according to claim 1, characterized in that The reaction pressure of the first hydrocracking reaction zone in step (2) is 0.5 to 4.0 MPa higher than the reaction pressure of the third hydrocracking reaction zone in step (4).

3. The method according to claim 1, characterized in that The properties of the vacuum residue in step (1) are as follows: initial distillation point of 420° C. to 620° C.; sulfur content by mass of 2% to 10%; nitrogen content by mass of 0.2% to 1.0%; and metal content of 100 mg / kg to 500 mg / kg.

4. The method according to claim 1, characterized in that The properties of the vacuum residue in step (1) are as follows: initial distillation point of 450° C. to 550° C.; sulfur content by mass of 4% to 8%; nitrogen content by mass of 0.3% to 0.5%; and metal content of 200 mg / kg to 300 mg / kg.

5. The method according to claim 1, characterized in that: The reaction conditions of the ebullated bed hydrogenation reaction zone in step (1) are as follows: reaction pressure of 10 MPa to 25 MPa; reaction temperature of 350°C to 500°C; hydrogen to oil volume ratio of 100:1 to 2000:1; volume space velocity of 0.1 h-1 to 1.5 h-1 -1 ; And / or, the ebullated bed hydrogenation reaction zone controls the conversion rate of the vacuum residue feedstock to be 60% to 90%; the conversion rate is the sum of the mass percentages of the gas fraction, light distillate oil and wax oil in the ebullated bed hydrogenation product relative to the fresh feedstock.

6. The method according to claim 1, characterized in that The reaction conditions of the ebullated bed hydrogenation reaction zone in step (1) are as follows: reaction pressure of 15 MPa to 20 MPa; reaction temperature of 400°C to 450°C; hydrogen to oil volume ratio of 300:1 to 1000:1; volume space velocity of 0.2 h-1 to 1.0 h-1; -1 ; And / or, the ebullated bed hydrogenation reaction zone controls the conversion rate of the vacuum residue feedstock to 70% to 80%; the conversion rate is the sum of the mass percentages of the gas fraction, light distillate oil and wax oil in the ebullated bed hydrogenation product relative to the fresh feedstock.

7. The method according to claim 1, characterized in that: The light distillate oil in step (1) has an initial boiling point of 60°C to 70°C and a final boiling point of 290°C to 320°C; And / or, the mass content of tricyclic aromatic hydrocarbons in the light distillate oil is 0.2% to 0.6%.

8. The method according to claim 1, characterized in that: The reaction pressure of the first hydrocracking reaction zone in step (2) is 6-10 MPa.

9. The method according to claim 1, characterized in that: The reaction pressure of the first hydrocracking reaction zone in step (2) is 7-9 MPa.

10. The method according to claim 1, characterized in that: The reaction conditions of the first hydrocracking reaction in step (2) are as follows: an average reaction temperature of 250-450°C; and / or a liquid hourly space velocity of 0.1-15.0 h -1 ; and / or, the hydrogen-to-oil volume ratio is 100:1 to 2500:

1.

11. The method according to claim 1, characterized in that: The reaction conditions of the first hydrocracking reaction in step (2) are as follows: an average reaction temperature of 300-400°C; and / or a liquid hourly volume space velocity of 1.0-5.0h -1 ; and / or, the hydrogen-to-oil volume ratio is 400:1 to 2000:

1.

12. The method according to claim 1, characterized in that: The reaction pressure of the second hydrocracking reaction zone in step (3) is 6-10 MPa.

13. The method according to claim 1, characterized in that: The reaction pressure of the second hydrocracking reaction zone in step (3) is 7-9 MPa.

14. The method according to claim 1, wherein: The reaction conditions of the second hydrocracking reaction zone in step (3) are as follows: average reaction temperature of 250-450°C; liquid hourly volume space velocity of 0.1-15.0h -1 ;The volume ratio of hydrogen to oil is 100:1~2500:

1.

15. The method according to claim 1, wherein: The reaction conditions of the second hydrocracking reaction zone in step (3) are as follows: average reaction temperature of 300-400°C; liquid hourly volume space velocity of 1.0-5.0h -1 ;The volume ratio of hydrogen to oil is 400:1~2000:

1.

16. The method according to claim 1, wherein: The reaction pressure of the third hydrocracking reaction zone in step (4) is 3-7 MPa.

17. The method according to claim 1, characterized in that: The reaction pressure of the third hydrocracking reaction zone in step (4) is 4-6 MPa.

18. The method according to claim 1, wherein: The reaction conditions of the third hydrocracking reaction zone in step (4) are as follows: average reaction temperature of 250-450°C; liquid hourly volume space velocity of 0.1-15.0h -1 ;The volume ratio of hydrogen to oil is 100:1~2500:

1.

19. The method according to claim 1, wherein: The reaction conditions of the third hydrocracking reaction zone in step (4) are as follows: average reaction temperature of 300-400°C; liquid hourly volume space velocity of 1.0-5.0h -1 ;The volume ratio of hydrogen to oil is 400:1~2000:

1.

20. The method according to claim 1, wherein: In the first hydrocracking catalyst, the molecular sieve is ZSM-5 molecular sieve; the Group VIB metal is molybdenum and / or tungsten; and the Group VIII metal is cobalt and / or nickel.

21. The method according to claim 1, wherein: In the second hydrocracking catalyst, the hydrogenation component is at least one of a metal, a metal oxide, and a metal sulfide of an active metal component; and the active metal component includes a VIB and / or VIII Group metal.

22. The method according to claim 21, characterized in that In the second hydrocracking catalyst, the active metal component is at least one of iron, chromium, molybdenum, tungsten, cobalt, and nickel.

23. The method according to claim 1, wherein: In the third hydrocracking product of step (4), the ratio of the mass of C6-C8 monocyclic cyclic hydrocarbons to the mass of the total cyclic hydrocarbons in the light distillate oil feedstock is 0.35-0.

55.

24. The method according to claim 1, wherein: In the third hydrocracking product of step (4), the ratio of the mass of C6-C8 monocyclic cyclic hydrocarbons to the mass of the total cyclic hydrocarbons in the light distillate oil feedstock is 0.44-0.50.

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