CN113462430B

CN113462430B - Method for producing low-carbon olefin and multiple aromatic hydrocarbons from petroleum hydrocarbons

Info

Publication number: CN113462430B
Application number: CN202010239538.3A
Authority: CN
Inventors: 唐津莲; 袁起民; 白风宇; 刘文明
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2020-03-30
Filing date: 2020-03-30
Publication date: 2023-03-24
Anticipated expiration: 2040-03-30
Also published as: CN113462430A

Abstract

The invention provides a method for producing low-carbon olefin and aromatic hydrocarbon, which comprises the following steps: (1) Sending heavy petroleum hydrocarbon into a first riser reactor for catalytic cracking; (2) Feeding the light petroleum hydrocarbon containing FCC light cycle oil fraction into a second riser reactor for hydrocatalytic cracking; (3) Carrying out first oil agent separation on the material led out by the first riser reactor to obtain a first oil-gas product and a first catalyst to be generated; (4) Performing second oil agent separation on the material led out by the second riser reactor to obtain a second oil gas product and a spent catalyst; (5) The first spent catalyst and the second spent catalyst are combined and then regenerated; (6) And combining the first oil gas product and the second oil gas product, and then carrying out rectification separation, gas separation and aromatic extraction separation. By adopting the technical scheme, the yield of the low-carbon olefin, C6-C8 aromatic hydrocarbon and naphthalene oil (BTXN) products is remarkably improved, and the yield of coke is remarkably reduced.

Description

Method for producing low-carbon olefin and multiple aromatic hydrocarbons from petroleum hydrocarbons

Technical Field

The invention relates to the field of petrochemical industry, in particular to a method for producing low-carbon olefin and various aromatic hydrocarbons from petroleum hydrocarbons.

Background

Low carbon olefin and BTXN (short for C6-C8 monocyclic aromatic hydrocarbon and naphthalene, alkyl naphthalene bicyclic aromatic hydrocarbon) are important chemical raw materials, and are mainly produced by catalytic cracking and thermal cracking.

The catalytic cracking process mainly comprises three parts: catalytic cracking of raw oil; regenerating the catalyst; and (5) separating a product. The raw material is sprayed into the lower part of the riser reactor, where it is mixed with a high-temperature catalyst, gasified and reacted. After the reaction oil gas and the catalyst are separated in the settler and the cyclone separator, the reaction oil gas enters a fractionating tower to separate out gasoline, diesel oil and heavy recycle oil. The cracked gas is compressed and then sent to a gas separation system. The coked catalyst is recycled after the regenerator burns off coke with air.

Thermal cracking is a process in which heavy oil undergoes a cracking reaction under the action of heat (without a catalyst) to convert into cracked gas, gasoline, and diesel. The thermally cracked feedstock is typically a heavy distillate or residue from a crude distillation process, or a heavy oil by-product of other petroleum refining processes. Thermal cracking processes are widely used in petroleum refining processes for cracking large molecules into small molecules.

However, in the existing catalytic cracking and thermal cracking methods, the yield of the low-carbon olefins, the C6-C8 aromatics and the naphthalene oil (BTXN) is low, the coke yield is high, and the increasing demands of chemical raw materials such as the low-carbon olefins and the aromatics are difficult to meet.

Disclosure of Invention

The invention aims to provide a method for producing low-carbon olefin and various aromatic hydrocarbons from petroleum hydrocarbons, which can obviously improve the yield of the low-carbon olefin, C6-C8 aromatic hydrocarbons and naphthalene oil (BTXN) products, reduce the yield of coke and convert more low-carbon olefin and aromatic hydrocarbons.

The inventors of the present invention have unexpectedly found that: in the catalytic cracking process, the hydrocatalytic cracking is added to treat the catalytic cracking cycle oil LCO, so that monocyclic aromatic hydrocarbon and bicyclic aromatic hydrocarbon with higher molecular weight in the LCO can be converted into BTXN, and the invention is obtained.

In order to achieve the above objects, the present invention provides a method for producing lower olefins and aromatic hydrocarbons, the method comprising: (1) Sending heavy petroleum hydrocarbon into a first riser reactor for catalytic cracking; (2) Feeding light petroleum hydrocarbon containing FCC light cycle oil fraction into a second riser reactor for hydrocatalysis cracking; (3) Carrying out first oil agent separation on the material led out by the first riser reactor to obtain a first oil-gas product and a first catalyst to be generated; (4) Performing second oil agent separation on the material led out by the second riser reactor to obtain a second oil gas product and a spent catalyst; (5) The first spent catalyst and the second spent catalyst are combined and then regenerated; (6) And combining the first oil gas product and the second oil gas product, and then carrying out rectification separation, gas separation and aromatic extraction separation.

By adopting the technical scheme, the yield of the low-carbon olefin, C6-C8 aromatic hydrocarbon and naphthalene oil (BTXN) products is remarkably improved, and the yield of coke is remarkably reduced.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of one embodiment of the present invention.

Description of the reference numerals

1 heavy petroleum hydrocarbon 2 atomizing medium I3 fluidizing medium I

4 reaction oil gas pipeline 5 fluidizing medium II 6 stripping medium I

7 stripping medium II 8 precision fractionating tower 9 cracked gas

10 light naphtha 11 light aromatic fraction 12 light cycle oil

13 heavy aromatic fraction 14 slurry oil 15 gas divides system

16 aromatic extraction system I17 aromatic extraction system II 18 low carbon olefin

19 C1-C4 alkane gas 20 light aromatic hydrocarbon 21 light aromatic hydrocarbon raffinate oil

22 heavy aromatics 23 heavy aromatics raffinate oil 24 spent pipeline I

25 regenerator 26 regeneration line I27 spent line II

28 catalyst lock hopper 29 spent line III 30 regenerant line II

31 regeneration pipeline III 32 oxygen-containing regeneration gas 33 flue gas

I first riser reactor and II second riser reactor

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The invention provides a method for producing low-carbon olefin and aromatic hydrocarbon, which comprises the following steps: (1) Sending heavy petroleum hydrocarbon into a first riser reactor for catalytic cracking; (2) Feeding light petroleum hydrocarbon containing FCC light cycle oil fraction into a second riser reactor for hydrocatalysis cracking; (3) Carrying out first oil agent separation on the material led out by the first riser reactor to obtain a first oil-gas product and a first catalyst to be generated; (4) Performing second oil agent separation on the material led out by the second riser reactor to obtain a second oil gas product and a spent catalyst; (5) The first spent catalyst and the second spent catalyst are combined and then regenerated; (6) And combining the first oil gas product and the second oil gas product, and then carrying out rectification separation, gas separation and aromatic extraction separation.

The first riser reactor and the second riser reactor may each be an ascending riser reactor or a descending riser reactor.

In the present invention, the first riser reactor and the second riser reactor may be each one selected from the group consisting of an equal-diameter riser, an equal-linear-velocity riser, a variable-diameter riser, and a variable-linear-velocity riser, or may be each a composite reactor comprising an equal-diameter riser or a variable-diameter riser, and preferably a composite reactor comprising a variable-diameter riser reactor and a riser.

Optionally, the conditions of the catalytic cracking in the first riser reactor comprise: the temperature is 500-750 ℃, the weight ratio of the solvent to the oil is 5-20, the reaction pressure is 0.1-1.0MPa, and the reaction time is 1-15 seconds;

optionally, the conditions of the hydrocatalytic cracking in the second riser reactor comprise: the temperature is 500-750 ℃, the weight ratio of the catalyst to the oil is 1.0-10, the reaction pressure is 0.1-10.0MPa, the reaction time is 0.1-20 seconds, the volume ratio of hydrogen to oil is 100-1000, and the apparent average linear velocity of oil gas is 0.5-5.0 m/s.

Preferably, the conditions of said catalytic cracking in said first riser reactor comprise: the temperature is 520-700 ℃, the weight ratio of the catalyst to the oil is 6-9, the reaction pressure is 0.2-0.9MPa, and the reaction time is 0.5-15 seconds.

Preferably, the conditions of the hydrocatalytic cracking in the second riser reactor comprise: the temperature is 520-700 ℃, the weight ratio of the catalyst to the oil is 3.0-9.0, the reaction pressure is 0.2-0.9MPa, the reaction time is 0.5-15 seconds, the volume ratio of hydrogen to oil is 150-800, and the apparent average linear velocity of oil gas is 1.0-4.0 m/s.

Wherein the catalytic cracking in the first riser reactor can be non-hydrocatalytic cracking.

Wherein the temperature in the first riser reactor and the second riser reactor can each be a reaction zone outlet temperature.

Optionally, the light petroleum hydrocarbons further comprise at least one of naphtha and hydrogenated FCC cycle oil fractions; the light petroleum hydrocarbons also optionally include at least one of dry gas, liquefied gas, and natural gas.

The heavy petroleum hydrocarbon includes at least one of wax oil, atmospheric residue, and hydrogenated residue.

Optionally, the light petroleum hydrocarbon has a carbon number of 1-20, a density of 600-920 kg/cubic meter, a carbon residue value of <1.0 wt%, and an end point of no greater than 360 ℃.

Optionally, the heavy petroleum hydrocarbon has a carbon number greater than 20, a density of 800 to 1100 kg/cubic meter, a sulfur content of <1.5 wt%, a nitrogen content of <0.5 wt%, a carbon residue value of <8.0 wt%, a metal Ni + V of <50 μ g/g, and a primary boiling point of not less than 360 ℃.

Optionally, the rectification separation separates the oil and gas product to obtain cracked gas, light naphtha fraction, light aromatic hydrocarbon fraction, light cycle oil fraction, heavy aromatic hydrocarbon fraction and oil slurry.

Optionally, the light naphtha fraction has an initial boiling point of 25-35 ℃ and an end point of 75-85 ℃.

Optionally, the light aromatic fraction has an initial boiling point of 75-85 ℃ and an end point of 155-175 ℃.

Optionally, the light cycle oil fraction has an initial boiling point of 155-175 ℃ and an end point of 230-250 ℃.

Alternatively, the heavy aromatic fraction has an initial boiling point of 230-250 ℃ and an end point of 355-385 ℃.

Where the "initial boiling point" and "end point" referred to in the present invention are point values for a defined fraction, one skilled in the art can select the "initial boiling point" and "end point" of the fraction within the above-mentioned temperature ranges and obtain the desired fraction by changing the distillation apparatus and conditions.

Optionally, the gas separation separates the cracked gas to obtain the low-carbon olefin and the remaining materials of the gas separation system.

Optionally, the aromatics extraction comprises light aromatics extraction and heavy aromatics extraction.

Optionally, the light aromatic fraction is separated by the light aromatic extraction to obtain light aromatic and light aromatic raffinate oil.

Optionally, separating the light aromatic fraction by the heavy aromatic extraction to obtain heavy aromatics and heavy aromatic raffinate oil.

Optionally, the lower olefins comprise at least one of ethylene, propylene, and C4 olefins; the light aromatic hydrocarbons comprise at least one of benzene, toluene and xylene; the heavy aromatic hydrocarbon comprises at least one of naphthalene, phenanthrene, anthracene, alkyl naphthalene, alkyl phenanthrene, and alkyl anthracene.

Optionally, the separated fraction may be recycled. For example, the method further comprises: blending a portion or all of at least one of the light naphtha fraction, the light aromatic raffinate oil, and the light cycle oil fraction into the light petroleum hydrocarbon for reprocessing; the method may also optionally include: mixing part or all of the heavy aromatic raffinate oil into the heavy petroleum hydrocarbon for recycling; the method may optionally further comprise: and (3) mixing part or all of the residual materials of the gas separation system into the light petroleum hydrocarbon and/or the pre-lifting medium of the second riser reactor for recycling. For another example, the second riser reactor comprises an alkane cracking zone and an aromatics cracking zone, the aromatics cracking zone disposed downstream of the alkane cracking zone; the method further comprises the following steps: introducing a portion or all of at least one of the light aromatic raffinate oil and the light cycle oil fraction into the light petroleum hydrocarbon for recycle to an aromatic cracking zone in the second riser; the method may optionally further comprise: mixing part or all of the heavy aromatic raffinate oil with the heavy petroleum hydrocarbon, and introducing the mixture into the first riser reactor for recycling; the method may optionally further comprise: and introducing part or all of the rest material of the gas separation system and part or all of the light naphtha fraction into the alkane cracking zone in the second riser for recycling.

Wherein some or all of the light petroleum hydrocarbons may be derived from material that is recycled in the process, such as between 50% and 100% of the light petroleum hydrocarbons are derived from material that is recycled in the process during normal operation of the process. Preferably, during normal operation of the process, all of the light petroleum hydrocarbons are derived from materials recycled in the process, for example, all of the light petroleum hydrocarbons are derived from at least one of the light naphtha fraction, the light aromatic raffinate oil, and the light cycle oil fraction, or all of the light petroleum hydrocarbons are derived from at least one of the light aromatic raffinate oil and the light cycle oil fraction; therefore, the whole method can only use the heavy petroleum hydrocarbon as net input raw material during normal operation, and fully utilize the heavy petroleum hydrocarbon to produce low-carbon olefin and C6-C8 aromatic hydrocarbon and naphthalene oil (BTXN) products, thereby improving the yield.

Preferably, in order to reduce the decrease in activity of the catalyst, the method further optionally comprises: before the heavy aromatic raffinate oil is partially or completely mixed into the heavy petroleum hydrocarbon for recycling, adsorption treatment and/or selective hydrogenation treatment are carried out to remove nitride, sulfide, colloid and/or heavy metal.

Optionally, the catalyst in the first riser reactor and the first riser reactor is a catalytic cracking catalyst with aromatization function containing medium pore zeolite and/or optionally large pore zeolite, inorganic oxide and optionally clay. The medium-pore zeolite and the large-pore zeolite can be modified by metal, nonmetal and the like. Preferably a catalytic cracking catalyst with aromatization function, which adopts transition metal such as Fe, co, ni, cu, zn and rare earth and/or nonmetal modified medium-pore zeolite such as P and large-pore zeolite as active components.

Optionally, wherein the catalytic cracking catalyst comprises: 1-50 wt% of zeolite, 5-95 wt% of inorganic oxide, 0-70 wt% of clay and modified metal component and modified non-metal component. Wherein the zeolite can be optional large-pore zeolite and medium-pore zeolite, and the large-pore zeolite accounts for 50-100 wt%, preferably 60-90 wt% of the total weight of the zeolite; the medium pore zeolite constitutes 0 to 50 wt%, preferably 10 wt% to 40 wt%, of the total weight of the zeolite. The large pore zeolite can be selected from Y series zeolite, including Rare Earth Y (REY), rare Earth Hydrogen Y (REHY), ultrastable Y obtained by different methods, and high silicon Y. The medium pore zeolite is selected from ZSM series zeolite and/or ZRP zeolite, and can be modified by nonmetal elements such as P; the ZSM-series zeolite may be one or a mixture of two or more selected from ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and other zeolites of similar structure. In addition, zeolites also include BETA-type molecular sieves having both a macroporous structure and a mesoporous structure.

The inorganic oxide may be selected from silicon dioxide (SiO) as a binder ₂ ) And/or aluminum oxide (Al) ₂ O ₃ ) On a dry weight basis, the inorganic oxide may have silica in an amount of 50 to 90 wt% and alumina in an amount of 10 to 50 wt%.

The clay as matrix (i.e. carrier) can be selected from one or more of silica, kaolin and/or halloysite, montmorillonite, diatomite, halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

The modified metal component has transition metal with dehydrogenation function, mainly is metal element of fourth and fifth periods of the transition metal, and preferably is oxide or hydroxide of any one or any two, three or more of transition metals such as Fe, co, ni, cu, zn, rare earth and the like. The modified metal component is present in an amount of 0 to 15 wt.%, preferably 1.0 to 10 wt.%, based on the metal oxide, based on the total weight of the catalyst.

Preferably, the catalyst is a catalytic cracking catalyst with aromatization function, which adopts metals such as Cu, P and the like, nonmetal-modified medium-pore zeolite and large-pore zeolite as active components.

Alternatively, as a preferred embodiment of the present invention, the catalyst in the first riser reactor and the first riser reactor comprises 15 to 22 wt% of DASY zeolite, 10 to 14 wt% of MFI structured mesoporous zeolite, 1.5 to 2.5 wt% of copper oxide, 0.5 to 1.2 wt% of phosphorus pentoxide, 20 to 25 wt% of pseudo-boehmite, 5 to 7 wt% of alumina sol and the balance kaolin.

According to the invention, the spent catalyst is regenerated; in the regeneration process, the regeneration gas can be one or more of air, oxygen and oxygen-containing gas, and the regeneration temperature can be 500-800 ℃, preferably 550-750 ℃. The heat exchange of the regenerated catalyst can be carried out by methods known to those skilled in the art to control the coke formation and the oil contact temperature.

For example, fig. 1 is a schematic process flow diagram of an embodiment of the present invention, in which a double-riser reactor is used, heavy petroleum hydrocarbons such as residual oil and the like are subjected to non-hydrocatalytic cracking in a first riser reactor, light hydrocarbons such as FCC light cycle oil and the like are subjected to high-temperature hydrocatalytic cracking reaction in a second riser reactor, and oil gas after the reaction enters a precise separation system for product separation and aromatic extraction. The process flow is as follows:

heavy petroleum hydrocarbon 1 is atomized by a hydrogen-free atomizing medium 2 and enters a first riser reactor I for catalytic cracking to produce low-carbon olefin and aromatic hydrocarbon, a reaction product and a spent catalyst with carbon after reaction are subjected to gas-solid separation, and the separated spent catalyst is subjected to steam stripping by a hydrogen-free steam stripping medium 6 and then is directly conveyed to a regenerator 25 through a regeneration pipeline 24; injecting light naphtha fraction, FCC light cycle oil fraction, hydrogenated FCC cycle oil fraction and/or dry gas, liquefied gas, natural gas and other light hydrocarbons into a second riser reactor II of the double-riser catalytic cracking device, and carrying out hydrocatalytic cracking reaction in the reaction atmosphere of a hydrogen-containing fluidized medium 5, wherein the light naphtha fraction, the FCC light cycle oil fraction, the hydrogenated FCC cycle oil fraction and/or the dry gas, the liquefied gas, the natural gas and the like can be fed at the same position of the second riser reactor II or can be fed at different positions in a partitioning manner, preferably injecting the light naphtha fraction and/or the dry gas, the liquefied gas, the natural gas and other light hydrocarbons into the lower part of the second riser reactor II, and injecting the FCC light cycle oil fraction, the hydrogenated FCC cycle oil fraction and other light hydrocarbons into the upper part of the second riser reactor II, so as to realize the light hydrocarbon partitioned hydrocatalytic cracking reaction; after gas-solid separation, the reaction product of the second riser reactor and the spent catalyst with carbon after reaction are stripped by a hydrogen-containing or hydrogen-free stripping medium 7, the stripped spent catalyst directly enters a regenerator through a spent pipeline 27 and/or enters a catalyst lock hopper 28 through the spent pipeline 27 for dehydrogenation and depressurization, and the spent catalyst after dehydrogenation and depressurization enters a regenerator 25 through a pipeline 29; oxygen-containing regeneration gas 32 is injected into the bottom of the regenerator, the spent catalysts from the two reactors are scorched and regenerated at 500-800 ℃ in the oxygen-containing atmosphere of the same regenerator 25, part of hot regenerated catalyst directly returns to the first riser reactor I for recycling, and part of hot regenerated catalyst directly returns to the second riser reactor II for recycling through a regeneration pipeline 30 and/or after being deoxidized and boosted through a catalyst lock hopper 28 and then returns through a regeneration pipeline 31; the reaction oil gas after oil separation of the two riser reactors enters an oil-gas separation system 8 through a reaction oil-gas pipeline 4, and cracked gas 9, light naphtha 10, light aromatic hydrocarbon fraction 11, light cycle oil 12, heavy aromatic hydrocarbon fraction 13, oil slurry 14 and the like are obtained through accurate separation; the cracked gas 9 is separated by a gas separation system 15 to obtain low-carbon olefin 18 and C1-C4 alkane gas 19; aromatic extraction is carried out on the light aromatic fraction 11 through an aromatic extraction system I16 to obtain light aromatic 20 such as benzene, toluene and xylene and light aromatic raffinate oil 21; the heavy aromatic hydrocarbon fraction 13 is subjected to aromatic hydrocarbon extraction by an aromatic hydrocarbon extraction system II 17 to obtain heavy aromatic hydrocarbons 22 such as naphthalene and methylnaphthalene and heavy aromatic hydrocarbon raffinate oil 22. Part of light naphtha 10 and C1-C4 alkane gas 19 are selected to be recycled to the reactor as hydrogen-containing fluidizing medium or pre-lifting medium for recycling according to requirements; the light cycle oil 12 and the light aromatic raffinate oil 21 are recycled or not recycled as required, and the second riser reactor II is preferentially selected to recycle and produce light olefins and aromatic hydrocarbons in an increased way; heavy aromatic raffinate oil is recycled or not recycled according to the requirement, and the heavy aromatic raffinate oil is preferably mixed with heavy oil in the first riser reactor I to recycle and produce aromatic hydrocarbon in a productive mode.

In this embodiment, the catalyst lock hopper is connected to the catalyst inlet and the catalyst outlet of the reactor device and to the catalyst inlet and the catalyst outlet of the regeneration device, so that the spent catalyst from the reactor device passes through the catalyst hopper system and enters the regeneration device for regeneration, and the regenerated catalyst from the regeneration device passes through the catalyst hopper system and is recycled to the reactor device.

The following examples further illustrate the process but are not intended to limit it.

The properties of the feedstock heavy petroleum hydrocarbons used in the examples are shown in table 1.

Catalyst preparation examples

The preparation of the catalysts used in the examples is as follows:

1) Dissolving 20kg ammonium chloride in 1000kg water, adding 100kg (dry basis) crystallization product DASY zeolite (produced by catalyst factory of Qilu petrochemical company, 2.445-2.448nm, rare earth content RE) ₂ O ₃ =2.0 wt%), exchanged for 0.5h at 90 ℃, and filtered to obtain a filter cake; 39.3kgCu (NO) was added ₃ ) ₂ ·6H ₂ Dissolving O in 203kg of water, mixing with the filter cake, soaking and drying; roasting at 550 deg.C for 2 hr to obtain copper-containing macroporous zeolite with elemental analysis chemical composition of 0.1Na ₂ O·5.1Al ₂ O ₃ ·18.2CuO·3.8RE ₂ O ₃ ·88.1SiO ₂ 。

2) 20kg of ammonium phosphate are dissolved in 500kg of water and stirred uniformly, 50kg of MFI structured mesoporous ZRP-1 zeolite (industrial product of catalyst plant of Qilu petrochemical company, siO) are added to the solution ₂ /Al ₂ O ₃ = 30), soaking and stirring for 3h at 60 ℃, and filtering to obtain a filter cake; the molecular sieve filter cake is dried at 120 ℃ and then roasted at 550 ℃ for 1 hour to obtain the phosphorus-containing mesoporous zeolite, wherein the phosphorus pentoxide content is 6.8 percent.

3) Pulping 75.4kg of halloysite (industrial product of Suzhou china clay company, with solid content of 71.6 m%) with 250kg of decationized water, adding 54.8kg of pseudo-boehmite (industrial product of Shandong aluminum plant, with solid content of 63 m%), adjusting the pH to 2-4 with hydrochloric acid, stirring uniformly, standing and aging at 60-70 deg.C for 1 hour, keeping the pH at 2-4, cooling to below 60 deg.C, adding 41.5kg of alumina sol (product of catalyst plant of Qilu petrochemical company, al) ₂ O ₃ Content 21.7 m%), and stirred for 40 minutes to obtain a mixed slurry.

4) Adding the copper-containing macroporous zeolite (33.8 kg in dry basis) prepared in the step 1) and the phosphorus-containing MFI structure mesoporous ZRP-1 zeolite (15.0 kg in dry basis) prepared in the step 2) into the mixed slurry obtained in the step 3), uniformly stirring, adding 4g of commercial aluminum oxide adhesive, mixing, putting into a bonder, adding a proper amount of water, fully and uniformly stirring, placing in the air for 4 hours, spray drying and forming, drying in a drying oven at 120 ℃ for 3 hours, and then using ammonium dihydrogen phosphate solution (with the phosphorus content of 1 weight) to dry%) washing to remove free Na ⁺ Washing to remove free Na ⁺ And drying again to obtain the catalyst which is marked as CAT-2. The catalyst comprises 18.9 wt% of DASY zeolite, 12.0 wt% of MFI structure mesoporous zeolite, 1.9 wt% of copper oxide, 0.8 wt% of phosphorus pentoxide, 22.8 wt% of pseudo-boehmite, 6.0 wt% of alumina sol and the balance of kaolin. The properties are shown in Table 2.

Example 1

This example was tested according to the apparatus and flow scheme of fig. 1, using the hydrogenated residue a in table 1 as heavy feed oil, on a small double riser reactor apparatus using a CAT-2 catalyst with catalyst MAT of 62. The catalyst inventory of the small double-riser reactor is 20 kg. Unlike conventional double riser reactor apparatus, in which the second riser reactor catalyst is in a turbulent fluidized state with an apparent average linear velocity of 1.0-3.0 m/s and is fluidized with hydrogen, the reaction pressure operating range is 0.1-10.0MPa.

Heavy petroleum hydrocarbon A enters a first lifting pipe of a double lifting pipe reactor device after being preheated at 280 ℃, flows from bottom to top along with steam of a fluidized medium without hydrogen under the reaction pressure of 0.4MPa, carries out catalytic cracking reaction under the conditions that the reaction temperature is 680-515 ℃, the weight ratio of a catalyst to raw oil is 6.8, the reaction time is 3.5 seconds and the weight ratio of atomized steam to total raw material is 0.10, and a spent catalyst after the reaction enters a regenerator for regeneration; the reacted oil gas enters a rectifying and fractionating tower for separation, the number of the separating tower plates of the rectifying and fractionating tower is 50, and cracked gas, light naphtha (37-80 ℃), light aromatic hydrocarbon fraction (78-170 ℃), light cycle oil (170-245 ℃), heavy aromatic hydrocarbon fraction (240-380 ℃), oil slurry and the like are obtained through accurate separation; separating the cracked gas by a gas separation system to obtain low-carbon olefin and residual materials (C1-C4 alkane gas) of the gas separation system; the light aromatic hydrocarbon fraction is subjected to aromatic extraction by an aromatic extraction system to obtain light aromatic hydrocarbons such as benzene, toluene and xylene and light aromatic hydrocarbon raffinate oil, and the heavy aromatic hydrocarbon fraction is subjected to aromatic extraction by an aromatic extraction system to obtain heavy aromatic hydrocarbons such as naphthalene and methylnaphthalene and heavy aromatic hydrocarbon raffinate oil; light hydrocarbon products such as light naphtha, light cycle oil, aromatic hydrocarbon raffinate oil and gas system residual materials (C1-C4 alkane gas) are remilled in a second lifting pipe by 100 percent, wherein the light naphtha and the gas system residual materials (C1-C4 alkane gas) are remilled in the lower part of the second lifting pipe, the light cycle oil and the aromatic hydrocarbon raffinate oil are remilled in the upper part of the second lifting pipe, the light cycle oil and the aromatic hydrocarbon raffinate oil are contacted with a thermal regenerant under the condition that the reaction pressure is 3.0MPa and the hydrogen partial pressure is 2.4MPa, the light cycle oil and the aromatic hydrocarbon raffinate oil flow from bottom to top along with a hydrogen-containing fluidizing medium, the light cycle oil and the aromatic hydrocarbon react at the reaction temperature of 680-560 ℃, the weight ratio of a catalyst to raw oil is 4.5, and the reaction time is 6.0 seconds, oil gas after the reaction enters a rectification fractionating tower for separation, and a spent catalyst is subjected to stripping and then is dehydrogenated, depressurized and enters a regenerator for regeneration; the regenerator adopts air as regeneration gas, and is contacted with a spent catalyst for regeneration at the regeneration temperature of 680-720 ℃ and the pressure of 0.5 MPa; the regenerated regenerant is recycled. The operating conditions and the product distribution are listed in Table 3.

As can be seen from table 3, in example 1, the heavy petroleum hydrocarbon is not hydrocatalytically cracked in one riser reactor of the dual riser reactor apparatus, while the light hydrocarbons such as light naphtha, light cycle oil, aromatic raffinate oil and C1-C4 alkane gas are refined back in the other riser reactor of the dual riser reactor apparatus for hydrocatalytic cracking, the cracked gas yield is 25.2 wt%, the BTX yield is 33.3 wt%, the heavy aromatic hydrocarbon yield is 24.3 wt%, and the triene (ethylene + propylene + butylene) yield is 21.4 wt%; the slurry yield was 4.1 wt% and the coke yield was 8.1 wt%.

Comparative example 1

Catalytic cracking was carried out by the same apparatus and method as in example 1, except that in comparative example 1: the second riser recycle gas is divided into the remaining materials (C1-C4 alkane gas), light naphtha and light cycle oil, and non-hydrocatalytic cracking is carried out in the second riser.

The catalyst and the process conditions of the comparative example are the same as those of the example 1, a CAT-2 catalyst is adopted, MAT of the catalyst is 62, heavy petroleum hydrocarbon A flows from bottom to top along with a non-hydrogen-containing fluidized medium under the reaction pressure of 0.4MPa, the catalytic cracking reaction is carried out at the reaction temperature of 680-515 ℃, the weight ratio of the catalyst to raw oil is 6.8, the reaction time is 3.5 seconds, the weight ratio of water vapor to the total raw material is 0.10, and the spent catalyst after the reaction is separated from reaction oil gas; oil gas after oil agent separation is accurately separated to obtain low-carbon olefin, residual materials (C1-C4 alkane gas) of a gas separation system, light naphtha (37-80 ℃), light aromatic hydrocarbon fraction (78-170 ℃), light cycle oil (170-245 ℃), heavy aromatic hydrocarbon fraction (240-380 ℃), oil slurry and the like; respectively performing aromatic extraction on the light aromatic hydrocarbon fraction and the heavy aromatic hydrocarbon fraction to obtain light aromatic hydrocarbon, heavy aromatic hydrocarbon and aromatic hydrocarbon raffinate oil; light hydrocarbons such as residual materials (C1-C4 alkane gas) of the gas separation system, light naphtha and raffinate oil of aromatic hydrocarbon are remixed in a second riser, the remixing proportion is 100 percent, and the light hydrocarbons react under the conditions that the reaction pressure is 0.4MPa, the reaction temperature is 680-560 ℃, the weight ratio of a catalyst to raw oil is 4.5 and the reaction time is 6.0 seconds; after steam stripping, the spent catalyst is regenerated by air at the regeneration temperature of 680-720 ℃ and the regenerator pressure of 0.6MPa, and the regenerated regenerant is recycled. The operating conditions and the product distribution are listed in Table 3.

As can be seen from table 3, example 1 (light hydrocarbon hydrocatalytic cracking) has high BTX yield and heavy aromatics yield and triene yield, and low coke yield, compared to comparative example 1 (light hydrocarbon non-hydrocatalytic cracking); the BTX yield, the heavy aromatic hydrocarbon yield and the triene yield are respectively improved by 9.7 percent, 4.6 percent and 2.9 percent, and the coke yield is reduced by 1.5 percent.

Example 2

This example was tested according to the apparatus and flow scheme of fig. 1, using atmospheric residuum B from table 1 as heavy feed oil and hydrogenated LCO as one of the light feeds, on a small dual riser reactor apparatus using a CAT-2 catalyst with catalyst MAT of 58. The catalyst inventory of the small double-riser reactor is 20 kg. Unlike conventional double riser reactor apparatus, in which the second riser reactor catalyst is in a turbulent fluidized state with an apparent average linear velocity of 1.0-3.0 m/s and is fluidized with hydrogen, the reaction pressure operating range is 0.1-10.0MPa.

Preheating heavy petroleum hydrocarbon B at 240 ℃, then entering a first riser of a double-riser reactor device, flowing from bottom to top along with a steam fluidized medium under the reaction pressure of 0.2MPa, carrying out catalytic cracking reaction at the reaction temperature of 700-550 ℃, the weight ratio of a catalyst to raw oil of 8.2, the reaction time of 5.5 seconds and the weight ratio of atomized steam to total raw material of 0.15, and feeding the reacted catalyst to be regenerated into a regenerator for regeneration; the reacted oil gas enters a rectifying fractionating tower for separation, the number of the separating tower plates of the rectifying fractionating tower is 50, and cracked gas, light naphtha (37-80 ℃), light aromatic hydrocarbon fraction (78-170 ℃), light cycle oil (170-245 ℃) and heavy aromatic hydrocarbon fraction (240-380 ℃) as well as oil slurry and the like are obtained through accurate separation; separating the cracked gas by a gas separation system to obtain low-carbon olefin and residual materials (C1-C4 alkane gas) of the gas separation system; the light aromatic hydrocarbon fraction is subjected to aromatic extraction by an aromatic extraction system to obtain light aromatic hydrocarbons such as benzene, toluene and xylene and light aromatic hydrocarbon raffinate oil, and the heavy aromatic hydrocarbon fraction is subjected to aromatic extraction by an aromatic extraction system to obtain heavy aromatic hydrocarbons such as naphthalene and methylnaphthalene and heavy aromatic hydrocarbon raffinate oil; light hydrocarbon products such as light naphtha, light cycle oil, aromatic raffinate oil and residual materials (C1-C4 alkane gas) of a gas separation system are remilled in a second lifting pipe by 70 percent, wherein the light naphtha and the residual materials (C1-C4 alkane gas) of the gas separation system are remilled in the lower part of the second lifting pipe, the light cycle oil, the aromatic raffinate oil and external hydrogenation LCO are remilled in the upper part of the second lifting pipe, under the reaction pressure of 1.0MPa, the hydrogen partial pressure of 0.8MPa is contacted with a thermal regenerant, the thermal regenerant flows from bottom to top along with a hydrogen-containing fluidized medium, the reaction temperature is 700-580 ℃, the weight ratio of a catalyst to raw oil is 6.4, and the reaction time is 2.0 seconds, oil gas after reaction enters a rectifying fractionating tower for separation, and a spent catalyst is subjected to steam stripping and then is subjected to pressure reduction through a catalyst lock hopper and enters a regenerator for regeneration; the regenerator takes air as regeneration gas, and contacts with the spent catalyst for regeneration at the regeneration temperature of 680-720 ℃ and the regenerator pressure of 0.4 MPa; the regenerated regenerant is recycled. The operating conditions and the product distribution are listed in Table 4.

As can be seen from table 4, in example 2, the heavy petroleum hydrocarbon is not hydrocatalytically cracked in one riser reactor of the dual riser reactor apparatus, while the light hydrocarbons such as light naphtha, light cycle oil, aromatic raffinate oil, and C1-C4 alkane gas are refined back in the other riser reactor of the dual riser reactor apparatus for hydrocatalytically cracking, the cracked gas yield is 41.2 wt%, the yield of trienes (ethylene + propylene + butylene) is 35.0 wt%, the BTX yield is 22.7 wt%, and the heavy aromatic hydrocarbon yield is 23.0 wt%; the coke yield was 6.4 wt%.

Comparative example 2

Catalytic cracking was carried out by the same apparatus and method as in example 2, except that in comparative example 2: the second riser recycles C1-C4 alkane gas, light naphtha, light cycle oil and hydrogenated LCO, and non-hydrocatalytic cracking is carried out in the second riser.

The catalyst and the process conditions of the comparative example are the same as those of the example 1, a CAT-2 catalyst is adopted, MAT of the catalyst is 62, heavy petroleum hydrocarbon B flows from bottom to top along with a non-hydrogen-containing fluidized medium under the reaction pressure of 0.3MPa, the catalytic cracking reaction is carried out at the reaction temperature of 680-515 ℃, the weight ratio of the catalyst to raw oil is 6.8, the reaction time is 3.5 seconds, the weight ratio of water vapor to the total raw material is 0.10, and the spent catalyst after the reaction is separated from reaction oil gas; oil gas after oil agent separation is accurately separated to obtain low-carbon olefin, C1-C4 alkane gas, light naphtha (37-80 ℃), light aromatic hydrocarbon fraction (78-170 ℃), light cycle oil (170-245 ℃), heavy aromatic hydrocarbon fraction (240-380 ℃), oil slurry and the like; respectively carrying out aromatic extraction on the light aromatic hydrocarbon fraction and the heavy aromatic hydrocarbon fraction to obtain light aromatic hydrocarbon, heavy aromatic hydrocarbon and aromatic hydrocarbon raffinate oil; light hydrocarbons such as C1-C4 alkane gas, light naphtha light hydrocarbon and aromatic raffinate oil are remixed at the maximum amount in a second riser, the remixing proportion is 100 percent, and the reaction is carried out under the conditions that the reaction pressure is 0.3MPa, the reaction temperature is 680-560 ℃, the weight ratio of a catalyst to raw oil is 6.4 and the reaction time is 2.0 seconds; after steam stripping, the spent catalyst is regenerated by air at the regeneration temperature of 680-720 ℃ and the regenerator pressure of 0.5MPa, and the regenerated regenerant is recycled. The operating conditions and the product distribution are listed in Table 4.

As can be seen from table 4, example 2 (light hydrocarbon hydrocatalytic cracking) has high BTX yield and heavy aromatics yield and triene yield, and low coke yield, compared to comparative example 2 (light hydrocarbon non-hydrocatalytic cracking); the BTX yield, the heavy aromatic hydrocarbon yield and the triene yield are respectively improved by 7.7 percent, 9.2 percent and 7.4 percent, and the coke yield is reduced by 0.7 percent.

Compared with the prior art, the invention also has the following technical effects: (1) The raw material adaptability is strong, and the method is not only suitable for high-quality catalytic cracking raw materials, but also suitable for deep catalytic cracking production chemical materials of poor heavy raw materials with high density and low hydrogen content; (2) The hydrocatalytic cracking dealkylation reaction of alkyl aromatic hydrocarbon in the FCC light cycle oil is realized by carrying out zoned hydrocatalytic cracking on the FCC light cycle oil fraction, the hydrogenated FCC cycle oil fraction and/or the light naphtha fraction, dry gas, liquefied gas, natural gas and the like in a special riser reactor, and the yield of low-carbon olefin and aromatic hydrocarbon materials is high, the coke formation is low and the hydrogen dependence is low compared with non-hydrocatalytic cracking; (3) The product scheme is flexible, and the accurate separation system not only can separate cracked oil gas to produce cracked gas, gasoline, diesel oil, slurry oil and heavy cycle oil, but also can accurately separate and produce low-carbon olefins, BTX, naphthalene, dimethylnaphthalene and other bicyclic aromatics and phenanthrene, anthracene and other tricyclic aromatics and other chemical materials, thereby meeting the requirement of a catalytic cracking device for producing aromatics; (4) The hydro-catalytic cracking of light hydrocarbon and the deep catalytic cracking of heavy oil are realized in one set of device, the process integration level is high, the device efficiency is high, and a catalytic cracking device of a riser reactor can be used for modification.

TABLE 1

TABLE 2

Catalyst numbering	CAT-2
		Chemical composition, weight%
Alumina oxide	42.8
		Copper oxide	1.9
Phosphorus pentoxide	0.8
		Sodium oxide	0.15
Rare earth element	1.4
		Apparent density, kg/m ³	848
Pore volume, ml/g	0.36
		Specific surface area, rice ² Per gram	178
Abrasion index in% by weight ^-1	1.2
		Sieving to obtain fine powder
0 to 40 microns	18.8
		40-80 microns	58.6
>80 micron	22.6

TABLE 3

	Example 1	Comparative example 1
			Raw oil	A	A
Reaction mode	Hydrocatalytic cracking of light hydrocarbons	Non-hydrocatalytic cracking of light hydrocarbons
			Name of catalyst	CAT-2	CAT-2
Catalyst Activity (MAT)	62	62
			Recycle ratio of light hydrocarbon	1.0	1.0
Reaction operating conditions
			First riser reactor
Reaction pressure, MPa	0.4	0.4
			Reactor inlet temperature,. Deg.C	680	680
Reactor outlet temperature,. Deg.C	515	515
			Catalyst/feed oil weight ratio	6.8	6.8
Oil gas residence time, s	3.5	3.5
			Weight ratio of atomized steam/total feedstock	0.10	0.10
Second riser reactor
			Reaction pressure, MPa	3.0	0.4
Partial pressure of hydrogen, MPa	2.4	～
			Reactor inlet temperature,. Deg.C	680	680
Reactor outlet temperature,. Deg.C	560	560
			Catalyst/feed oil weight ratio	4.5	4.5
Oil gas residence time, s	6.0	6.0
			H ₂ Volume ratio of oil to oil	800	～
Weight ratio of atomized steam/total feedstock	～	0.05
			Product yield, weight%
Cracked gas	25.2	26.4
			Wherein ethylene is	2.1	1.8
Propylene (PA)	12.9	11.1
			Butene (butylene)	6.4	5.5
Light aromatic hydrocarbon (78-170 degree)	38.3	33.7
			Wherein BTX	33.3	23.6
Heavy aromatic hydrocarbon (240-380 deg.C)	24.3	26.4
			Wherein the naphthalene	4.9	2.6
Methylnaphthalene	10.9	7.9
			Phenanthrene and anthracene	7.3	7.9
Oil slurry	4.1	3.9
			Coke	8.1	9.6
Total up to	100.00	100.0

TABLE 4

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims

1. A method for producing low-carbon olefin and a plurality of aromatic hydrocarbons by petroleum hydrocarbons is characterized by comprising the following steps:

(1) Sending heavy petroleum hydrocarbon into a first riser reactor for catalytic cracking;

(2) Feeding the light petroleum hydrocarbon containing FCC light cycle oil fraction into a second riser reactor for hydrocatalytic cracking;

(3) Carrying out first oil agent separation on the material led out by the first riser reactor to obtain a first oil-gas product and a first catalyst to be generated;

(4) Performing second oil agent separation on the material led out by the second riser reactor to obtain a second oil gas product and a second spent catalyst;

(5) The first spent catalyst and the second spent catalyst are combined and then regenerated;

(6) Combining the first oil gas product and the second oil gas product, and then carrying out rectification separation, gas separation and aromatic extraction separation;

the conditions of the catalytic cracking in the first riser reactor include: the temperature is 500-750 ℃, the weight ratio of the solvent to the oil is 5-20, the reaction pressure is 0.1-1.0MPa, and the reaction time is 1-15 seconds;

the conditions for the hydrocatalytic cracking in the second riser reactor comprise: the temperature is 500-750 ℃, the weight ratio of the catalyst to the oil is 1.0-10, the reaction pressure is 0.1-10.0MPa, the reaction time is 0.1-20 seconds, the volume ratio of hydrogen to oil is 100-1000, and the apparent average linear velocity of oil gas is 0.5-5.0 m/s;

the catalyst in the first riser reactor and the second riser reactor is a catalytic cracking catalyst with aromatization function containing medium pore zeolite and/or optional large pore zeolite, inorganic oxide and optional clay.

2. The process of claim 1, wherein the conditions of the catalytic cracking in the first riser reactor comprise: the temperature is 520-700 ℃, the weight ratio of the catalyst to the oil is 6-9, the reaction pressure is 0.2-0.9MPa, and the reaction time is 0.5-15 seconds;

the conditions of the hydrocatalytic cracking in the second riser reactor comprise: the temperature is 520-700 ℃, the weight ratio of the catalyst to the oil is 3.0-9.0, the reaction pressure is 0.2-0.9MPa, the reaction time is 0.5-15 seconds, the volume ratio of hydrogen to oil is 150-800, and the apparent average linear velocity of oil gas is 1.0-4.0 m/s.

3. The method of claim 1 or 2, wherein the light petroleum hydrocarbons further comprise at least one of naphtha and hydrogenated FCC cycle oil fractions;

4. The method of claim 3, wherein the light petroleum hydrocarbon further comprises at least one of dry gas, liquefied gas, and natural gas.

5. The method of claim 3, wherein the light petroleum hydrocarbon has a carbon number of 1-20, a density of 600 to 920 kg/m, a carbon residue value of <1.0 wt%, and an end point of no greater than 360 ℃;

wherein the carbon number of the heavy petroleum hydrocarbon is more than 20, the density is 800 to 1100 kg/cubic meter, the sulfur content is less than 1.5 weight percent, the nitrogen content is less than 0.5 weight percent, the carbon residue value is less than 8.0 weight percent, the metal Ni + V is less than 50 mu g/g, and the initial boiling point is not less than 360 ℃.

6. The method of claim 1 or 2, wherein the rectification separation separates the oil and gas product to obtain cracked gas, a light naphtha fraction, a light aromatic hydrocarbon fraction, a light cycle oil fraction, a heavy aromatic hydrocarbon fraction, and oil slurry;

the initial boiling point of the light naphtha fraction is 25-35 ℃, and the final boiling point is 75-85 ℃;

the initial boiling point of the light aromatic hydrocarbon fraction is 75-85 ℃, and the final boiling point is 155-175 ℃;

the initial boiling point of the light cycle oil fraction is 155-175 ℃, and the final boiling point is 230-250 ℃;

the initial boiling point of the heavy aromatic hydrocarbon fraction is 230-250 ℃, and the final boiling point is 355-385 ℃;

the gas separation separates the cracked gas to obtain low-carbon olefin and residual materials of a gas separation system;

the aromatic extraction comprises light aromatic extraction and heavy aromatic extraction;

separating the light aromatic hydrocarbon fraction through light aromatic hydrocarbon extraction to obtain light aromatic hydrocarbon and light aromatic hydrocarbon raffinate oil;

separating the light aromatic hydrocarbon fraction through heavy aromatic hydrocarbon extraction to obtain heavy aromatic hydrocarbon and heavy aromatic hydrocarbon raffinate oil;

the low-carbon olefin comprises at least one of ethylene, propylene and C4 olefin; the light aromatic hydrocarbons comprise at least one of benzene, toluene and xylene; the heavy aromatic hydrocarbon comprises at least one of naphthalene, phenanthrene, anthracene, alkyl naphthalene, alkyl phenanthrene and alkyl anthracene.

7. The method of claim 6, wherein the method further comprises: blending a portion or all of at least one of the light naphtha fraction, the light aromatic raffinate oil, and the light cycle oil fraction into the light petroleum hydrocarbon for reprocessing.

8. The method of claim 7, wherein the method further comprises: and (3) mixing part or all of the heavy aromatic raffinate oil into the heavy petroleum hydrocarbon for recycling.

9. The method of claim 7, wherein the method further comprises: and (3) mixing part or all of the residual materials of the gas separation system into the light petroleum hydrocarbon and/or the pre-lifting medium of the second riser reactor for recycling.

10. The process of claim 6 wherein said second riser reactor comprises an alkane cracking zone and an aromatics cracking zone, said aromatics cracking zone disposed downstream of said alkane cracking zone;

the method further comprises the following steps: and introducing part or all of at least one of the light aromatic raffinate oil and the light cycle oil fraction into the light petroleum hydrocarbon to be conducted into the aromatic hydrocarbon cracking zone for recycling.

11. The method of claim 10, wherein the method further comprises: and (3) mixing part or all of the heavy aromatic raffinate oil into the heavy petroleum hydrocarbon for recycling.

12. The method of claim 10, wherein the method further comprises: and introducing part or all of the rest material of the gas separation system and part or all of the light naphtha fraction into the alkane cracking zone for remilling.

13. The method of claim 7, wherein, during normal operation of the method, 50% -100% of the light petroleum hydrocarbons originate from material refined back in the method.

14. The method of claim 13, wherein the method further comprises: before the heavy aromatic raffinate oil is partially or completely mixed into the heavy petroleum hydrocarbon for recycling, adsorption treatment and/or selective hydrogenation treatment are carried out to remove nitride, sulfide, colloid and/or heavy metal.

15. The process of claim 1 wherein the catalyst in the first riser reactor and the second riser reactor is a catalytic cracking catalyst with aromatization function employing transition metal and/or P-modified medium pore zeolite and large pore zeolite together as active components.

16. The method according to claim 15, wherein the transition metal is selected from one or more of Fe, co, ni, cu, zn and rare earths.

17. The process of claim 15 wherein the catalyst in the first riser reactor and the second riser reactor comprises 15-22 wt% DASY zeolite, 10-14 wt% MFI structured mesoporous zeolite, 1.5-2.5 wt% copper oxide, 0.5-1.2 wt% phosphorus pentoxide, 20-25 wt% pseudoboehmite, and 5-7 wt% alumina sol with the balance being kaolin clay.