A processing method for co-producing chemical raw materials by combining coking and hydrocracking

Abstract

The present invention discloses a processing method for co-producing chemical raw materials by combining coking and hydrocracking. The method includes: the coking raw material enters the delayed coking reaction zone for thermal cracking reaction to obtain petroleum coke and a gaseous effluent; the gaseous effluent is fractionated to obtain coker dry gas and coker whole fraction oil; the initial boiling point of the coker whole fraction oil is 50°C to 80°C, and the final boiling point is 460°C to 520°C; in the presence of hydrogen, the coker whole fraction oil enters the first hydrocracking reaction zone to obtain a first hydrocracking product; the mass content of C7 + normal paraffins in the first hydrocracking product is controlled at 0.1% to 5.0%; the first hydrocracking product enters the second hydrocracking reaction zone, and the obtained second hydrocracking product is separated and fractionated to obtain a gas fraction, light naphtha, heavy naphtha and tail oil. This method uses heavy oils such as vacuum residue as raw materials, and can improve the quality and yield of chemical raw materials.

Description

Technical Field

[0001] The present invention belongs to the field of heavy oil processing, and particularly relates to a processing method combining delayed coking and hydrocracking, especially a processing method for producing high-quality chemical raw materials using vacuum residue as a raw material. Background Art

[0002] Reducing the production of heavy fuel oil is the development trend of the world's refining industry today. At present, the capacity of catalytic cracking for single refining and blending of residue has accounted for more than 25% of the total capacity of catalytic cracking, but not all residues can be processed by catalytic cracking. When the carbon residue content of the residue exceeds 10% and the metal content exceeds 100 - 150 ppm, the residue hydrotreating / catalytic cracking combined unit also has difficulty bearing the increasingly high catalyst costs and increasingly long shutdown times. Coupled with the growing demand for light oil products, the widening price difference between light crude oil and heavy high-sulfur crude oil, and the increasing proportion of heavy sulfur-containing / high-sulfur crude oil supply, especially since delayed coking can process cheap heavy high-sulfur high-metal residues, and coker gasoline can be used as a raw material for ethylene production after hydrogenation, delayed coking has thus become the most popular technology for residue processing and the preferred residue processing scheme for many refineries.

[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 prepare a first hydrocracking product stream; b) separating the first hydrocracking product stream to provide at least one light hydrocarbon stream containing at least C2 and C3 hydrocarbons, an intermediate hydrocarbon stream composed of C4 and / or C5 hydrocarbons, and a heavy hydrocarbon stream containing at least C6+ hydrocarbons, and c) subjecting the heavy hydrocarbon stream to a second hydrocracking in the presence of a second hydrocracking catalyst to prepare a second hydrocracking product stream containing BTX, wherein the second hydrocracking is more severe than the first hydrocracking, d) wherein, in the presence of a C4 hydrocracking catalyst, at least part of the intermediate hydrocarbon stream is subjected to C4 hydrocracking to prepare 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 a hydrocarbon raw material, comprising the following steps: (a) feeding the hydrocarbon raw material 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 in step (c) into an overhead stream containing hydrogen, methane, ethane, and liquefied petroleum gas and a stream containing 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 alkanes, cycloalkanes, and aromatics. Among them, alkanes, especially small-molecule alkanes, are high-quality ethylene raw materials, while cycloalkanes and aromatics are high-quality reforming feeds. Delayed coking causes heavy raw materials to undergo thermal cracking, following the free radical reaction mechanism. The products have a high content of normal hydrocarbons and cyclic hydrocarbons. In the prior art, it is impossible to efficiently achieve the conversion effect of "ethylene production when suitable for ethylene, and aromatics production when suitable for aromatics" for coker distillate oil. Therefore, it is of great significance to develop a processing method suitable for using heavy oils such as vacuum residue as raw materials and producing high-quality chemical raw materials through delayed coking and hydrocracking. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, the object of the present invention is to provide a processing method for jointly producing chemical raw materials by coking and hydrocracking. This method uses heavy oils such as vacuum residue as raw materials, which can significantly improve the quality and yield of chemical raw materials.

[0007] The present invention provides a processing method for jointly producing chemical raw materials by coking and hydrocracking, and the method includes:

[0008] (1) The coking raw material enters the delayed coking reaction zone for thermal cracking reaction to obtain petroleum coke and gaseous effluent; the gaseous effluent is fractionated to obtain coker dry gas and coker whole fraction oil; wherein, the initial boiling point of the coker whole fraction oil is 50°C to 80°C, and the final boiling point is 460°C to 520°C;

[0009] (2) In the presence of hydrogen, the coker whole fraction oil obtained in step (1) enters the first hydrocracking reaction zone to selectively crack the normal alkanes in the first hydrocracking product to obtain the first hydrocracking product; wherein, in the first hydrocracking product, the mass content of C7 + normal alkanes is controlled at 0.1% to 5.0%;

[0010] (3) In the presence of hydrogen, the first hydrocracking product enters the second hydrocracking reaction zone to obtain a second hydrocracking product containing monocyclic cyclic hydrocarbons;

[0011] (4) The second hydrocracking product obtained in step (3) is separated and fractionated to obtain gas fraction, light naphtha, heavy naphtha, and tail oil.

[0012] According to the present invention, the coking feedstock oil in step (1) is generally heavy oil with an initial boiling point greater than 350 °C, and can be selected from one or more of atmospheric residue, vacuum residue, visbreaking residue, heavy deasphalted oil, catalytic cracking slurry, heavy oil, topped crude oil, shale oil, and coal liquefied oil, preferably vacuum residue. The initial boiling point of the vacuum residue is 420 °C to 620 °C, preferably 450 °C to 550 °C; the sulfur mass content is 2% to 10%, preferably 4% to 8%; the nitrogen mass content is 0.2% to 1.0%, preferably 0.3% to 0.5%; the metal content is 100 mg / kg to 500 mg / kg, preferably 200 mg / kg to 300 mg / kg.

[0013] According to the present invention, the temperature in the delayed coking reaction zone in step (1) is 480 to 520 °C, preferably 490 to 505 °C; the operating pressure is 0.1 MPa to 2 MPa, preferably 0.2 MPa to 0.5 MPa, and it can be a constant pressure operation or a variable pressure operation; the recycle ratio is 0.1 to 0.5, preferably 0.2 to 0.4, and the recycle ratio is the mass ratio of the coking whole fraction oil to the feedstock oil.

[0014] According to the present invention, the initial boiling point of the coking whole fraction oil in step (1) is 60 °C to 70 °C, and the final boiling point is 480 °C to 500 °C.

[0015] According to the present invention, the mass content of aromatics with more than three rings in the coking whole fraction oil in step (1) is not higher than 1.0%, preferably 0.2% to 0.6%.

[0016] According to the present invention, the coking whole fraction oil may contain impurities such as sulfur and nitrogen. According to actual needs, a hydrofining catalyst can be set upstream of the first hydrocracking catalyst to remove impurities such as sulfur and nitrogen. Among them, the nitrogen content in the reaction fluid stream in contact with the first hydrocracking catalyst is preferably below 100 mg / kg, and more preferably below 50 mg / kg.

[0017] According to the present invention, preferably, in step (2), the mass content of C7 + n-alkanes is controlled at 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 raw material to produce BTX, and ethane, propane, butane, and light naphtha are used as raw materials for producing light olefins. For example, they are used as steam cracking raw materials to produce ethylene, and propane and butane can also be directly dehydrogenated to produce propylene and butene. Among them, light olefins refer to olefins with four or fewer carbon atoms, especially ethylene, propylene, and butadiene.

[0019] According to the present invention, in step (2), the first hydrocracking reaction zone is filled with a first hydrocracking catalyst, and the first hydrocracking catalyst can be one or more catalysts. In step (2), the first hydrocracking catalyst includes an active metal component and a support; the support includes a molecular sieve having selective cracking of normal paraffins, preferably 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, preferably ZSM-5 molecular sieve. The SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 20 to 60. The support may further include a binder. Preferably, the binder is alumina. The active metal component includes at least one of metals of Group VIB and Group VIII, the metal of Group VIB is preferably molybdenum and / or tungsten, and the metal of Group VIII is preferably cobalt and / or nickel.

[0020] According to the present invention, in step (2), preferably, in the first hydrocracking catalyst, based on the weight of the catalyst, the content of the metal of Group VIB (calculated as the oxide) is 5.0% to 15.0%, the content of the metal of Group VIII (calculated as the oxide) is 2.0% to 5.0%, and the content of the support is 80.0% to 93.0%.

[0021] According to the present invention, in step (2), preferably, in the support of the first hydrocracking catalyst, based on the weight of the support, the content of the binder is 8% to 60%, and the content of the molecular sieve is 40% to 92%.

[0022] 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 to 0.45 cm 3 / g. The particle size of the second hydrocracking catalyst is 1.0 to 3.0 μm.

[0023] According to the present invention, in step (2), the preparation method of the first hydrocracking catalyst can be prepared according to the conventional methods in the art. The preparation method includes the preparation of the support and the loading of the active metal component, and the process of preparing the support is as follows: The shape-selective cracking molecular sieve and the binder are mechanically mixed, formed, and then dried and calcined to make the catalyst support. The drying and calcination of the support can adopt conventional conditions. The conditions for drying are: drying at 100°C to 150°C for 1 to 12 hours. The conditions for calcination are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0024] 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 kneading method, impregnation method, etc., and the impregnation method is preferably used. The impregnation method can be saturated impregnation method, excess impregnation method or complex impregnation method, that is, the catalyst support is impregnated with a solution containing the required active component, and then dried and calcined to obtain the second hydrocracking catalyst. The conditions for the drying are: drying at 100°C to 150°C for 1 to 12 hours. The conditions for the calcination are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0025] According to the present invention, in step (2), the reaction conditions in the first hydrocracking reaction zone are as follows: the reaction pressure is 14 to 17 MPa, preferably 15 to 16 MPa.

[0026] According to the present invention, in step (2), the reaction conditions for the first hydrocracking reaction are as follows: the average reaction temperature is 250 to 450°C, preferably 300 to 400°C; the liquid hourly space velocity is 0.1 to 15.0 h -1 , preferably 1.0 to 5.0 h -1 ; the hydrogen-oil volume ratio is 100:1 to 2500:1, preferably 400:1 to 2000:1.

[0027] According to the present invention, in the second hydrocracking product of step (3), the mass ratio of the C6-C8 monocyclic cyclic hydrocarbons to the total cyclic hydrocarbon mass in the coking whole fraction oil raw material is 0.20 to 0.40, preferably 0.30 to 0.36.

[0028] According to the present invention, in step (3), the second hydrocracking catalyst has the functions of ring opening and cracking of polycyclic cyclic hydrocarbons, selectively cracking isoparaffins or side chains of cyclic hydrocarbons and retaining monocyclic cyclic hydrocarbons. The second hydrocracking catalyst includes a cracking component, a hydrogenation component and a binder. The second hydrocracking catalyst can be a commercially available product or prepared according to the prior art. The hydrogenation component is at least one of a metal, a metal oxide, and a metal sulfide of the active metal component; the active metal component includes Group VIB and / or Group VIII metals; the active metal component is more preferably at least one of iron, chromium, molybdenum, tungsten, cobalt, and nickel. In the second hydrocracking catalyst, the binder is alumina and / or silica; the cracking component includes an acidic molecular sieve, preferably at least one of Beta molecular sieve and Y molecular sieve.

[0029] According to the present invention, preferably, in step (3), the catalysts with Y molecular sieve as the cracking component and the catalysts with Beta molecular sieve as the cracking component are sequentially loaded along the material flow direction in the second hydrocracking reaction zone; preferably, the volume ratio of the catalyst with Y molecular sieve as the cracking component to the catalyst with Beta molecular sieve as the cracking component is 5:1 to 1:2, preferably 3:1 to 1:1.

[0030] According to the present invention, in step (3), for the second hydrocracking catalyst, based on the weight of the second hydrocracking catalyst, the content of the hydrogenation component in terms of oxide 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%.

[0031] According to the present invention, in step (3), the preparation method of the second hydrocracking catalyst can be prepared according to the conventional methods in the art. The preparation method includes the preparation of the carrier and the loading of the hydrogenation component. The process of preparing the carrier is as follows: mechanically mix the cracking component and the binder, shape it, and then dry and calcine it to make the catalyst carrier. The drying and calcining of the carrier can adopt conventional conditions. The conditions for drying are: drying at 100°C to 150°C for 1 to 12 hours. The conditions for calcining are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0032] According to the present invention, in step (3), in the preparation method of the second hydrocracking catalyst, the method for loading the hydrogenation component is a conventional method, such as the kneading method, the impregnation method, etc., and the impregnation method is preferred. The impregnation method can be the saturated impregnation method, the excess impregnation method or the complex impregnation method, that is, impregnate the catalyst carrier with a solution containing the required hydrogenation component, and then dry and calcine it to obtain the second hydrocracking catalyst. The conditions for drying are: drying at 100°C to 150°C for 1 to 12 hours. The conditions for calcining are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0033] According to the present invention, in step (3), the reaction conditions in the second hydrocracking reaction zone are as follows: the reaction pressure is 14 to 17 MPa, preferably 15 to 16 MPa.

[0034] According to the present invention, in step (3), the reaction conditions in the second hydrocracking reaction zone are as follows: the average reaction temperature is 250 to 450°C, preferably 300 to 400°C; the liquid hourly space velocity is 0.1 to 15.0 h -1 , preferably 1.0 to 5.0 h -1 ; the hydrogen-oil volume ratio is 100:1 to 2500:1, preferably 400:1 to 2000:1.

[0035] According to the present invention, preferably, the first hydrocracking reaction zone and the second hydrocracking reaction zone adopt the same pressure.

[0036] According to the present invention, preferably, the effluent of the second hydrocracking reaction in step (3) is subjected to supplementary hydrofining. The supplementary hydrofining can be carried out by loading a hydrofining catalyst at the bottom of the second hydrocracking reaction zone, or it can enter a separate hydrofining reaction zone.

[0037] According to the present invention, preferably, the effluent of the second hydrocracking reaction in step (3) can also directly enter the fractionation system first, and the heavy naphtha fraction obtained by separation is subjected to supplementary hydrofining.

[0038] According to the present invention, the tail oil obtained in step (3) is recycled to the second hydrocracking reaction zone.

[0039] Compared with the prior art, the present invention has the following beneficial technical effects:

[0040] (1) In the prior art, when hydrocracking coker wax oil as a raw material to produce chemical raw materials, the final boiling point of the coker wax oil separated by the fractionating tower is generally 520 - 560 °C, resulting in a relatively high content of aromatic hydrocarbons with more than three rings in the wax oil fraction. A relatively high reaction pressure is required to achieve the hydrocracking of tricyclic aromatic hydrocarbons. However, a relatively high reaction pressure will also cause the ring opening and cracking of some monocyclic aromatic hydrocarbons during the hydrocracking process, resulting in the loss of aromatic hydrocarbons. In the processing method for co-producing chemical raw materials of the present invention, by controlling the content of aromatic hydrocarbons with more than three rings in the whole coker wax oil fraction to be no higher than 1%, and selecting an appropriate reaction pressure, the mixed processing of aromatic hydrocarbons with less than three rings is realized, reducing the loss of aromatic hydrocarbons during the hydrogenation process of the raw material and increasing the content of aromatic hydrocarbons in the hydrogenation product. Specifically, the whole coker oil fraction and hydrogen enter the first hydrocracking reaction zone, mainly selectively cracking the n-alkanes in the raw material and the long straight chains of isoparaffins and naphthenes with long straight chains to generate small molecule n-alkanes, so that the content of C7 + n-alkanes in the effluent of the first hydrocracking reaction is 0.1% - 5.0%. The effluent of the first hydrocracking reaction enters the second hydrocracking reaction zone, mainly to crack the multi-ring cyclic hydrocarbons and retain the monocyclic cyclic hydrocarbons and further break the side chains in each hydrocarbon to generate small molecule hydrocarbons. In this way, a large amount of the chain alkanes in the raw material can be converted into gas and light naphtha components, that is, enriched in ethylene raw materials, while the monocyclic cyclic hydrocarbons are retained in the heavy naphtha fraction, that is, enriched in reforming raw materials. The efficient separation of paraffins and cyclic hydrocarbons can be achieved through simple fractionation, increasing the production of high-quality ethylene cracking feedstock while improving the quality of heavy naphtha as a catalytic reforming feedstock.

[0041] Petroleum hydrocarbons have a complex composition, mainly including alkanes, cycloalkanes and aromatics. High-quality ethylene feedstock is small-molecule n-alkanes, and reforming feedstock is monocyclic cycloalkanes and aromatics. Through research, the inventors found that the technical solution of the present invention can retain monocyclic cyclic hydrocarbons as much as possible and selectively generate small-molecule n-alkanes, thereby realizing the efficient enrichment of small-molecule n-alkanes in light olefin feedstock, and at the same time retaining monocyclic cyclic hydrocarbons in heavy naphtha as much as possible to achieve the efficient enrichment of high-quality reforming feedstock. In this way, the purpose of significantly improving the yields of chemical raw materials (i.e., ethylene feedstock and reforming feedstock) and the quality of ethylene feedstock and reforming feedstock can be achieved, and thus the present invention is completed.

[0042] (2) The heavy naphtha obtained by the method of the present invention has a high content of monocyclic cyclic hydrocarbons. As the feed for the catalytic reforming unit, the alkane cyclization and dehydrogenation unit in the catalytic reforming unit can be cancelled, and the investment and energy consumption of the catalytic reforming unit can be greatly reduced. At the same time, since the hydrocracking reaction follows the carbocation reaction mechanism, the side-chain breaking reaction of cyclic hydrocarbons above C9 can be selectively realized, so that the C6-C8 cyclic hydrocarbons in the product have a high enrichment degree, and the BTX yield can be greatly improved after catalytic reforming and aromatics extraction.

[0043] (3) The present invention selectively converts the alkanes in the coking whole-fraction oil into small-molecule alkanes. This process consumes a certain amount of hydrogen, but the light hydrocarbons also have a high hydrogen yield as the feedstock for the ethylene unit, and 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 unit. At the same time, the light hydrocarbons as the ethylene feedstock can greatly improve the yields of ethylene, propylene and butadiene, and extend the cleaning cycle of the ethylene unit, significantly improving the economic benefits of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a process flow schematic diagram of Embodiments 1-4 of the present invention;

[0045] Main reference numeral descriptions:

[0046] 1 - vacuum residue, 2 - delayed coking reaction zone, 3 - petroleum coke, 4 - delayed coking gas-phase effluent, 5 - fractionating tower, 6 - coking gas fraction, 7 - coking whole-fraction oil, 8 - hydrogen, 9 - first hydrocracking reaction zone, 10 - first hydrocracking reaction effluent, 11 - second hydrocracking reaction zone, 12 - second hydrocracking reaction effluent, 13 - separator, 14 - gas-phase stream hydrogen-rich gas, 15 - liquid-phase stream, 16 - fractionating tower, 17 - gas fraction, 18 - light naphtha, 19 - heavy naphtha, 20 - tail oil. DETAILED DESCRIPTION OF THE INVENTION

[0047] The functions and effects of the present invention will be further illustrated by the following examples, but the following examples do not limit the method of the present invention.

[0048] In the present invention, unless otherwise specified, % is by mass fraction.

[0049] The overall volumetric space velocity in the examples and comparative examples is the ratio of the fresh feed volume to the total catalyst volume.

[0050] The method of the present invention, as Figure 1 shown, includes: vacuum residue 1 enters the delayed coking reaction zone 2 to obtain petroleum coke 3 and delayed coking gas-phase effluent 4, the delayed coking gas-phase effluent 4 enters the fractionating tower 5 for separation to obtain coking gas fraction 6 and coking whole fraction oil 7, the coking whole fraction oil 7 is mixed with hydrogen 8 and enters the first hydrocracking reaction zone 9 for the first hydrocracking reaction, the first hydrocracking reaction effluent 10 enters the second hydrocracking reaction zone 11 for the second hydrocracking reaction, the second hydrocracking reaction effluent 12 enters the separator 13, the separated gas-phase stream hydrogen-rich gas 14 is recycled, the liquid-phase stream 15 enters the fractionating tower 16, and gas fraction 17, light naphtha 18, heavy naphtha 19 and tail oil 20 are fractionated, and the tail oil 20 is recycled to the second hydrocracking reaction zone 11.

[0051] 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. The first hydrocracking catalyst is prepared by the conventional active metal saturation impregnation method, and the physicochemical properties of the obtained catalyst are shown in Table 1.

[0052] In the present invention, the second hydrocracking catalyst in each example is represented by Cat-B plus a number, such as Cat-B1, Cat-B2. The physicochemical properties of the catalyst are shown in Table 2. The second hydrocracking catalyst in each example is prepared by the conventional active metal saturation impregnation method. Among them, the properties of the Beta zeolite used in Cat-B2 are as follows: the SiO2 / Al2O3 molar ratio is 30, the specific surface area is 350 m 2 / g, the pore volume is 0.32 cm 3 / g, the properties of the Y zeolite used in Cat-B1 are as follows: the SiO2 / Al2O3 molar ratio is 15, the specific surface area is 400 m 2 / g, the pore volume is 0.30 cm 3 / g.

[0053] In the present invention, the feedstock oil in each example uses vacuum residue, and its main properties are shown in Table 3.

[0054] In the present invention, the nitrogen content in the reaction stream in contact with the first hydrocracking catalyst in each example is below 50 mg / kg

[0055] In the present invention, the ethylene raw materials in each example refer to ethane, propane, butane and light naphtha obtained in step (3), and ethane, propane, butane and light naphtha can be directly used as raw materials for steam cracking to produce ethylene.

[0056] In the present invention, the distillation range of light naphtha is the liquid component with a distillation range less than 60 °C, the distillation range of heavy naphtha is 60 - 175 °C, and the distillation range of tail oil is the component with a distillation range > 175 °C.

[0057] In the present invention, the yield of ethylene raw materials refers to the mass ratio of ethane, propane, butane and light naphtha in the hydrocracking product to the fresh hydrocracking raw material (coking whole fraction oil), and the yield of heavy naphtha refers to the mass ratio of heavy naphtha in the hydrocracking product to the fresh hydrocracking raw material (coking whole fraction oil).

[0058] Examples 1 - 4

[0059] The processing method for co-producing chemical raw materials by combining coking and hydrocracking adopts the following Figure 1 process, including:

[0060] (1) The vacuum residue enters the delayed coking reaction zone for thermal cracking reaction to obtain petroleum coke and a gas-phase effluent; the gas-phase effluent enters the fractionating tower to obtain coker dry gas and coking whole fraction oil;

[0061] (2) The coking whole fraction oil is mixed with hydrogen and sequentially enters the first hydrocracking reaction zone and the second hydrocracking reaction zone; the first hydrocracking reaction zone is filled with a first hydrocracking catalyst; the second hydrocracking reaction zone is filled with a second hydrocracking catalyst; control the content of C7 + n-alkanes in the effluent of the first hydrocracking reaction in step (2) and the content of polycyclic alkanes in the product of the second hydrocracking reaction.

[0062] (3) The effluent of the second hydrocracking reaction zone is subjected to gas-liquid separation to obtain a gas-phase stream and a liquid-phase stream; among them, the gas-phase stream is recycled, and the liquid-phase stream enters the fractionating tower for fractionation to obtain a gas fraction, light naphtha, heavy naphtha and tail oil.

[0063] The process conditions and hydrocracking effects in each example are shown in Table 5.

[0064] Comparative Example 1

[0065] The difference from Example 1 is that the coking whole fraction oil directly enters the second hydrocracking reaction zone after hydrofining.

[0066] The process conditions and hydrocracking effects in this example are shown in Table 5.

[0067] Comparative Example 2

[0068] The difference from Example 1 is that in step (2), control the C7 in the effluent of the second hydrocracking reaction+ The mass content of n-alkanes is 6%.

[0069] In this example, the process conditions and the hydrogenation effect are shown in Table 5.

[0070] Comparative Example 3

[0071] The difference from Example 1 is that: the catalyst loading order in the second hydrocracking reaction zone is different from that in Example 1. In this example, the order of catalysts Cat-B1 and Cat-B2 is exchanged. Specifically, in this example, the catalysts Cat-B2 and Cat-B1 are loaded successively along the material flow direction in the hydrocracking reaction zone.

[0072] In this example, the process conditions and the hydrogenation effect are shown in Table 5.

[0073] Comparative Example 4

[0074] The difference from Example 1 is that: the mass content of aromatics with more than three rings in the coker whole distillate oil is 3.5%.

[0075] In this example, the process conditions and the hydrogenation effect are shown in Table 5.

[0076] Table 1 Physicochemical properties of the first hydrocracking catalyst

[0077] Catalyst Cat-A1 Cat-A2 Cat-A3 <![CDATA[Pore volume, cm 3 / g]]> 0.35 0.45 0.25 <![CDATA[Specific surface area, m 2 / g]]> 300 200 400 Content, wt%, based on the weight of the support ZSM-5 58 42 85 Aluminum oxide 42 58 15 Active metal content in the catalyst, wt% <![CDATA[MoO3]]> 10.0 15.0 5.0 NiO 3.5 2.0 5.0 Support content in the catalyst, wt% 86.5 83.0 90.0 <![CDATA[SiO2 / Al2O3 molar ratio of ZSM-5]]> 40 60 20

[0078] Table 2 Physicochemical properties of the second hydrocracking catalyst

[0079]

[0080]

[0081] Table 3 Main properties of the feedstock oil

[0082] Name of the feedstock Vacuum residue <![CDATA[Density (20 °C) / kg·m -3 > 1.032 Distillation range / °C 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

[0083] Table 4 Delayed coking process conditions and main properties of the coker whole distillate oil

[0084]

[0085] Continued Table 4

[0086]

[0087]

[0088] Table 5 Hydrogenation effect

[0089]

[0090] Continued Table 4

[0091]

[0092]

[0093] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A processing method for co-producing chemical raw materials by combining coking and hydrocracking, characterized in that, The method includes: (1) The coking feedstock oil enters the delayed coking reaction zone for thermal cracking reaction to obtain petroleum coke and gaseous effluent; the gaseous effluent is fractionated to obtain coker dry gas and coker whole fraction oil; wherein, the initial boiling point of the coker whole fraction oil is 50°C to 80°C, and the final boiling point is 460°C to 520°C; (2) In the presence of hydrogen, the coking whole fraction oil obtained in step (1) enters the first hydrocracking reaction zone to selectively crack the n-alkanes in the first hydrocracking product, obtaining the first hydrocracking product; wherein, in the first hydrocracking product, the mass content of C7 + n-alkanes is controlled to be 0.1% to 5.0%; (3) In the presence of hydrogen, the first hydrocracking product enters the second hydrocracking reaction zone to obtain a second hydrocracking product containing monocyclic cyclic hydrocarbons; (4) The second hydrocracking product obtained in step (3) is separated and fractionated to obtain gas fraction, light naphtha, heavy naphtha and tail oil; In step (1), the mass content of aromatics with more than three rings in the coker whole fraction oil is not higher than 1.0%; In step (2), the first hydrocracking reaction zone is filled with a first hydrocracking catalyst; the first hydrocracking catalyst includes an active metal component and a carrier; the carrier includes a molecular sieve with selective cracking of normal paraffins, and the molecular sieve is 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 includes at least one of Group VIB metals and Group VIII metals; For the first hydrocracking catalyst, based on the weight of the catalyst, the content of Group VIB metal in terms of oxide is 5.0% to 15.0%, the content of Group VIII metal in terms of oxide is 2.0% to 5.0%, and the content of the carrier is 80.0% to 93.0%; in the carrier of the first hydrocracking catalyst, based on the weight of the carrier, the content of the binder is 8% to 60%, and the content of the molecular sieve is 40% to 92%; In step (3), the second hydrocracking reaction zone is filled with a second hydrocracking catalyst; the second hydrocracking catalyst includes a cracking component, a hydrogenation component and a binder; in step (3), the second hydrocracking reaction zone is filled with a catalyst with Y molecular sieve as the cracking component and a catalyst with Beta molecular sieve as the cracking component in sequence along the material flow direction; In the second hydrocracking catalyst, based on the weight of the second hydrocracking catalyst, the content of the hydrogenation component in terms of oxide is 5wt% to 40wt%; the content of the cracking component is 10wt% to 80wt%; the content of the binder is 5wt% to 85wt%; The chemical raw materials include ethane, propane, butane, light naphtha and heavy naphtha. Among them, heavy naphtha is used as a reforming raw material to produce BTX, and ethane, propane, butane and light naphtha are used as raw materials for producing low-carbon olefins.

2. The method according to claim 1, wherein The coking feedstock oil in step (1) is heavy oil with an initial boiling point greater than 350°C, and is selected from one or several of atmospheric residue, vacuum residue, visbreaking residue, heavy deasphalted oil, catalytic cracking slurry, heavy oil, topped crude oil, shale oil and coal liquefied oil.

3. The method according to claim 1, characterized in that The coking feedstock oil is vacuum residue; the initial boiling point of the vacuum residue is 420°C to 620°C; the sulfur mass content is 2% to 10%; the nitrogen mass content is 0.2% to 1.0%; the metal content is 100 mg / kg to 500 mg / kg.

4. The method according to claim 3, characterized in that, The initial boiling point of the vacuum residue is 450°C to 550°C; the sulfur mass content is 4% to 8%; the nitrogen mass content is 0.3% to 0.5%; the metal content is 200 mg / kg to 300 mg / kg.

5. The method according to claim 1, wherein In step (1), the initial boiling point of the coking whole fraction oil is 60°C to 70°C, and the final boiling point is 480°C to 500°C; And / or, the mass content of aromatics with more than three rings in the coking whole fraction oil is 0.2% to 0.6%.

6. The method according to claim 1, wherein In step (1), the temperature of the delayed coking reaction zone is 480 to 520°C; the operating pressure is 0.1 MPa to 2 MPa; the recycle ratio is 0.1 to 0.5, and the recycle ratio is the mass ratio of the coking whole fraction oil to the coking feedstock oil.

7. The method according to claim 1, wherein In step (1), the temperature of the delayed coking reaction zone is 490 to 505°C; the operating pressure is 0.2 MPa to 0.5 MPa; the recycle ratio is 0.2 to 0.4, and the recycle ratio is the mass ratio of the coking whole fraction oil to the coking feedstock oil.

8. The method according to claim 1, characterized in that, In the first hydrocracking catalyst, the molecular sieve is ZSM-5 molecular sieve; the Group VIB metals are molybdenum and / or tungsten, and the Group VIII metals are cobalt and / or nickel.

9. The method according to claim 1, wherein In step (2), the reaction pressure of the first hydrocracking reaction zone is 14 to 17 MPa.

10. The method according to claim 1, wherein In step (2), the reaction pressure of the first hydrocracking reaction zone is 15 to 16 MPa.

11. The method according to claim 1, wherein In step (2), the reaction conditions in the first hydrocracking reaction zone are as follows: the average reaction temperature is 250~450°C; the liquid hourly space velocity is 0.1~15.0 h -1 ; the hydrogen-oil volume ratio is 100:1~2500:

1.

12. The method according to claim 1, wherein The reaction conditions in the first hydrocracking reaction zone in step (2) are as follows: the average reaction temperature is 300~400°C; the liquid hourly space velocity is 1.0~5.0 h -1 ; the hydrogen-oil volume ratio is 400:1~2000:

1.

13. The method according to claim 1, wherein C7 in step (2) + The mass content of the n-alkane is controlled at 1.0% to 3.0%.

14. The method according to claim 1, wherein In the second hydrocracking catalyst, based on the weight of the second hydrocracking catalyst, the content of the hydrogenation component calculated as the oxide is 10 wt% to 30 wt%; the content of the cracking component is 20 wt% to 60 wt%; the content of the binder is 10 wt% to 50 wt%; And / or, in the second hydrocracking catalyst, the hydrogenation component is at least one of the metal, metal oxide, and metal sulfide of the active metal component; the active metal component includes Group VIB and / or Group VIII metals; And / or, in the second hydrocracking catalyst, the binder is alumina and / or silica; And / or, in the second hydrocracking catalyst, the volume ratio of the catalyst with Y molecular sieve as the cracking component to the catalyst with Beta molecular sieve as the cracking component is 5:1 to 1:

2.

15. The method according to claim 1, characterized in that, In the second hydrocracking catalyst, the volume ratio of the catalyst with Y molecular sieve as the cracking component to the catalyst with Beta molecular sieve as the cracking component is 3:1 to 1:

1.

16. The method according to claim 14, wherein In the second hydrocracking catalyst, the active metal component is at least one of iron, chromium, molybdenum, tungsten, cobalt, and nickel.

17. The method according to claim 1, characterized in that In step (3), the reaction pressure of the second hydrocracking reaction zone is 14 to 17 MPa.

18. The method according to claim 1, wherein In step (3), the reaction pressure of the second hydrocracking reaction zone is 15 to 16 MPa.

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

1.

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

1.

21. The method according to claim 1, wherein The first hydrocracking reaction zone and the second hydrocracking reaction zone adopt the same pressure.

Images