Method for increasing yield of lightweight aromatic hydrocarbons

Abstract

The present disclosure relates to a method for increasing the yield of lightweight aromatic hydrocarbons. In the method, a lightening reaction is performed by introducing a gasoline heavy fraction into a lightening reactor and bringing same into contact with a lightening catalyst therein so as to obtain a lightweight reaction product, thereby efficiently converting heavy aromatic hydrocarbons in the gasoline heavy fraction into light aromatic hydrocarbons. The problems of high hydrogen consumption, harsh operation conditions and aromatic hydrocarbon loss caused by the production of light aromatic hydrocarbons by means of using a hydrogenation treatment can be avoided; moreover, the problem of low-value heavy aromatic hydrocarbons being difficult to utilize can be solved, thereby achieving efficient utilization of resources. The lightening reactor is a dense-phase fluidized bed reactor, such that the gasoline heavy fraction can be fully reacted, and thus the yield of light aromatic hydrocarbons can be further improved. In addition, by using the method of the present disclosure, low-carbon olefins can also be produced as a by-product, thereby further improving the utilization rate of raw materials.

Description

A method for increasing the production of light aromatics Technical Field

[0001] The present disclosure relates to the field of petrochemical industry, and in particular, to a method for increasing the production of light aromatics, preferably a method for increasing the production of light aromatics by re-converting catalytic cracking gasoline. Background Art

[0002] BTX (B stands for benzene, T for toluene, and X for xylene) is a key petrochemical product and a vital raw material for a variety of chemical products, including synthetic rubber, synthetic fibers, and synthetic resins. Toluene and xylene can also be used as gasoline octane additives. However, the aromatics production process is accompanied by the production of C9+ heavy aromatics. Currently, C9+ heavy aromatics are produced in large quantities, have low value, and have limited utilization options, resulting in resource waste. Converting C9+ heavy aromatics into BTX is undoubtedly an effective way to fully utilize resources and improve quality and efficiency for enterprises.

[0003] CN1217370A discloses a process for the hydrodealkylation and transalkylation of heavy aromatic hydrocarbons. Using C10 and / or C11 aromatic hydrocarbons as feedstock, the process proceeds in a fixed-bed reactor using a hydrogen-type mordenite catalyst loaded with bismuth and at least one metal or oxide selected from iron, cobalt, nickel, or molybdenum at a temperature of 300-600°C and a pressure of 1.5-4.0 MPa to produce C6-C9 aromatic hydrocarbons and C1-C4 paraffins. This process is particularly suitable for the hydrodealkylation and transalkylation of C10 and / or C11-heavy aromatic hydrocarbons and can be used in industrial production.

[0004] CN1752058A discloses a method for the hydrodealkylation and transalkylation of heavy aromatics, primarily addressing the low allowable heavy aromatic content in the feedstock and the resulting low utilization rate of heavy aromatics, a problem encountered in prior art. This method effectively addresses this problem by using C10 and / or C11 aromatics as feedstock, using a large-pore zeolite loaded with bismuth and molybdenum metals or oxides as a catalyst in a fixed-bed reactor to produce mixed xylenes at temperatures of 300-600°C and pressures of 1.0-4.0 MPa. This method boasts a simple process, high mixed xylene yield, and a low hydrogen-to-hydrocarbon ratio, making it suitable for the industrial production of mixed xylenes from heavy aromatics.

[0005] CN1906272A discloses a process for the separate catalytic hydrodealkylation of hydrocarbons comprising C8-C13 alkylaromatic compounds, optionally mixed with C4-C9 aliphatic and alicyclic products. The process comprises continuously treating the hydrocarbon composition with a catalyst comprising ZSM-5 zeolite modified with at least one metal selected from Groups IIB, VIB, and VIII in the presence of hydrogen at a temperature of 400-650°C, a pressure of 2-4 MPa, and a H2 / feedstock molar ratio of 3-6. This process can achieve a benzene + toluene yield of up to 75%.

[0006] CN101348733A3 discloses a method for producing light aromatics and light alkanes from hydrocarbon feedstocks. The method involves reacting a hydrocarbon feedstock with a boiling point of 30 to 250°C in the presence of a Pt or Pd-containing zeolite catalyst. Heavy aromatics in the hydrocarbon feedstock undergo hydrodealkylation and transalkylation with light aromatics. The light aromatics undergo isomerization and are converted into components rich in BTX (B is benzene, T is toluene, and X is xylene) light aromatics. Non-aromatics undergo hydrocracking to produce light alkanes. In a distillation tower, the liquid products are separated into benzene, toluene, xylene, and C9+ aromatics, respectively, based on their boiling points. The light alkanes are separated from the gaseous products. This method addresses the technical issues of traditional hydrocarbon feedstock separation processes requiring solvent extraction, resulting in complex and costly processes and low utilization value of heavy aromatics and separated non-aromatics.

[0007] CN101734986A discloses a method for producing more benzene and xylene by hydrocracking pyrolysis gasoline. This method involves reacting a C7+ pyrolysis gasoline feedstock in the presence of a catalyst. Heavy aromatics undergo hydrodealkylation and transalkylation with light aromatics. The light aromatics undergo an isomerization reaction to convert them into components rich in BTX light aromatics. The liquid products are separated into benzene, toluene, xylene, and a C9+ fraction based on their boiling points. The toluene and C9+ fractions can be returned as feed for further processing, while the light alkanes can be separated from the gaseous products. This method addresses the problem of conventional pyrolysis gasoline processes that simply separate BTX aromatics, resulting in a high concentration of toluene in the light aromatics product, and the low utilization value of the separated heavy aromatics and non-aromatics.

[0008] As can be seen from the technology disclosed in the aforementioned patent application, existing technologies for converting heavy aromatics to lightweight hydrocarbons mostly use fixed-bed hydrodealkylation. However, the hydrogenation process suffers from problems such as high hydrogen consumption, harsh operating conditions, and aromatics loss.

[0009] Summary of the Invention

[0010] The present disclosure provides a method for increasing the production of light aromatics to solve the problems of high hydrogen consumption, harsh operating conditions, aromatics loss and low resource utilization in existing hydrogenation technologies.

[0011] To achieve the above-mentioned object, the present disclosure provides a method for increasing the production of light aromatics, characterized in that the method comprises: allowing a gasoline heavy fraction to enter a lightening reactor and contact it with a lightening catalyst therein to cause a lightening reaction to occur, thereby obtaining a lightening reaction product; subjecting the lightening reaction product to a product separation treatment; or allowing the lightening reaction product to enter a first reactor of a cracking reaction unit; the lightening reactor is a dense phase fluidized bed reactor having a bed density of 180-700 kg / m 3 ; The catalyst activity of the light-weight reactor catalyst is 50-99, wherein the gasoline heavy fraction comprises a C9+ fraction.

[0012] Optionally, the method further comprises: allowing the heavy oil feedstock, alone or together with the lightening reaction product, to enter the first reactor of the cracking reaction unit, and contacting the heavy oil feedstock with a cracking catalyst therein to cause a cracking reaction to occur, thereby obtaining a cracking reaction product; performing product separation treatment on the cracking reaction product or performing product separation treatment together with the lightening reaction product to obtain other products, light gasoline, a gasoline middle fraction, and a gasoline heavy fraction; preferably, performing aromatics separation treatment on the gasoline middle fraction to obtain a benzene product, a toluene product, and a xylene product.

[0013] Optionally, the heavy oil feedstock includes petroleum hydrocarbons and / or other mineral oils; the petroleum hydrocarbons are selected from one of vacuum wax oil, atmospheric wax oil, coker wax oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, extracted oil and inferior recycled oil, or a mixture thereof; the other mineral oils are selected from one of coal liquefaction oil, oil sands oil and shale oil, or a mixture thereof.

[0014] The initial distillation point of the heavy oil raw material is 200-400°C, preferably 250-350°C; the final distillation point is 450-600°C, preferably 500-550°C.

[0015] Optionally, the reaction conditions of the cracking reaction include: reaction temperature of 520-720°C, preferably 550-700°C; reaction time of 1-10s, preferably 1.5-6s; catalyst-oil ratio of (1-100):1, preferably (10-50):1; the reaction conditions of the lightening reaction include: reaction temperature of 530-730°C, preferably 560-680°C; catalyst-oil ratio of (1-100):1, preferably (5-30):1; catalyst activity of 60-90.

[0016] Optionally, the cracking catalyst and the lightening catalyst are the same or different; the cracking catalyst and the lightening catalyst each independently comprise zeolite, an inorganic oxide and optionally clay; based on the total weight of the cracking catalyst or the lightening catalyst, the content of the zeolite is 5-70 weight %, preferably 30-60 weight %; the content of the inorganic oxide is 1-95 weight %, preferably 30-70 weight %; and the content of the clay is 1-50 weight %, preferably 5-40 weight %.

[0017] Optionally, the zeolite of the cracking catalyst includes large-pore zeolite and optional medium-pore zeolite; based on the total weight of the zeolite in the cracking catalyst, the content of large-pore zeolite is 30-99 weight%, preferably 40-80 weight%, and the content of medium-pore zeolite is 1-70 weight%, preferably 20-60 weight%; the zeolite of the lightweighting catalyst includes large-pore zeolite and medium-pore zeolite; based on the total weight of the zeolite in the lightweighting catalyst, the content of large-pore zeolite is 50-99 weight%, preferably 60-80 weight%, and the content of medium-pore zeolite is 1-50 weight%, preferably 20-40 weight%.

[0018] Optionally, the medium-pore zeolite is ZSM zeolite; the large-pore zeolite is selected from one or more of β zeolite and Y zeolite; the inorganic oxide includes silicon dioxide and / or aluminum oxide; and the clay is kaolin and / or halloysite.

[0019] Optionally, the cracking catalyst and the lightening catalyst respectively contain rare earth elements. Preferably, the large-pore zeolite is β-zeolite or Y-type zeolite modified with rare earth elements.

[0020] Optionally, the first reactor is a riser reactor, a fluidized bed reactor or a combination of the two.

[0021] Optionally, the first reactor and the lightweight reactor are arranged in parallel or in series; when the first reactor and the lightweight reactor are arranged in series, the first reactor is arranged downstream of the lightweight reactor.

[0022] Optionally, the cracking reaction unit also includes a regenerator; the method also includes separating the catalyst to be regenerated and the cracking reaction product after the reaction in the first reactor; allowing the catalyst to be regenerated to enter the regenerator for regeneration treatment to obtain a regenerated catalyst; returning the regenerated catalyst to the first reactor, preferably returning to the first reactor through a first regeneration inclined tube and / or returning the regenerated catalyst to the lightening reactor, preferably returning to the lightening reactor through a second regeneration inclined tube; or, separating the cracking catalyst to be regenerated and the cracking reaction product after the reaction in the first reactor; separating the lightened catalyst to be regenerated and the lightened reaction product after the reaction in the lightening reactor; allowing the cracking catalyst to be regenerated and the lightened catalyst to be regenerated to enter the same or respective regenerators for regeneration treatment to obtain a regenerated cracking catalyst and a regenerated lightened catalyst; returning the regenerated cracking catalyst to the first reactor, preferably returning to the first reactor through a third regeneration inclined tube, and returning the regenerated lightened catalyst to the lightening reactor, preferably returning to the lightening reactor through a fourth regeneration inclined tube.

[0023] Optionally, fresh agent is added to the lightening reaction, wherein a fresh agent inlet is provided on the second regeneration inclined tube and / or at the bottom of the lightening reactor; or, a fresh agent inlet is provided on the fourth regeneration inclined tube and / or at the bottom of the lightening reactor; or, an overflow hopper is provided in the regenerator, and a fresh agent inlet is provided in the regenerator overflow hopper.

[0024] Optionally, the product separation process includes: subjecting the cracking reaction product to a first separation to obtain the other products, the light gasoline and heavy gasoline; and subjecting the heavy gasoline to a second separation to obtain the gasoline middle fraction and the gasoline heavy fraction.

[0025] Optionally, the initial boiling point of the light gasoline is 20-40°C; the distillation cut point between the light gasoline and the heavy gasoline is 80-100°C; and the distillation cut point between the gasoline middle fraction and the gasoline heavy fraction is 120-150°C.

[0026] Optionally, the bed density of the fluidized bed reactor is 300-500 kg / m 3 , the bed linear velocity is 0.1-3 m / s, preferably 0.4-2 m / s.

[0027] Optionally, the light gasoline is returned to the cracking reaction unit for the cracking reaction.

[0028] Optionally, the method further comprises adding a fresh agent into the lightening reactor; and the ratio of the amount of fresh agent added to the amount of catalyst circulation in the cracking reaction unit is less than 0.2.

[0029] Through the above technical solution, the present disclosure can efficiently convert heavy aromatics in heavy oil cracking products into light aromatics by subjecting heavy oil raw materials to catalytic cracking reactions. On the one hand, it can avoid the problems of high hydrogen consumption, harsh operating conditions and aromatics loss caused by the use of hydroprocessing to produce light aromatics; on the other hand, it can solve the problem of low-value heavy aromatics being difficult to utilize, and achieve efficient utilization of resources. In addition, the heavy fraction of gasoline is recycled in a light-weight reactor, wherein the light-weight reactor is a dense phase fluidized bed reactor, which can fully react the heavy fraction of gasoline, thereby further improving the yield of light aromatics. In addition, the method disclosed in the present disclosure can also produce low-carbon olefins as by-products, further improving the utilization rate of raw materials.

[0030] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0032] FIG1 is a schematic diagram of a method for catalytically cracking gasoline and then converting it to increase the production of light aromatics according to the present invention.

[0033] FIG2 is a schematic diagram of a specific embodiment of a cracking reaction unit used in the method of the present disclosure.

[0034] FIG3 is a schematic diagram of a second specific embodiment of a cracking reaction unit used in the method of the present disclosure.

[0035] FIG4 is a schematic diagram of a third specific embodiment of a cracking reaction unit used in the method of the present disclosure.

[0036] FIG5 is a schematic diagram of a cracking reaction unit used in Comparative Example 3 of the present disclosure.

[0037] Explanation of the reference numerals 1 heavy oil feedstock; 2 cracking reaction unit; 3 cracking reaction product; 4 product separation unit; 5 light gasoline; 6 gasoline middle fraction; 7 gasoline heavy fraction; 8 other products; 9 aromatics separation unit; 10 benzene product; 11 toluene product; 12 xylene product; 13 lightening reactor; 14 riser reactor; 15 fluidized bed reactor; 16 settler; 17 regeneration inclined pipe; 18 regenerator; 19 second regeneration inclined pipe; 20 first regeneration inclined pipe; 21 regenerated flue gas; 22 fresh agent; 23 fresh agent; 24 riser reactor; 40 cracking settler; 41 lightening settler; 42 cracking regeneration inclined pipe; 43 third regeneration inclined pipe; 44 lightening regeneration inclined pipe; 45 fourth regeneration inclined pipe; 46 cracking regenerator; 47 lightening regenerator; 48 lightening reaction product; 49 cracking reaction product; 50 regeneration inclined pipe.

[0038] Like or similar reference numbers identify like or similar parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0039] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0040] Any specific numerical value disclosed herein (including the endpoints of a numerical range) is not limited to the exact value of the numerical value, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Moreover, for a disclosed numerical range, any combination of the endpoints of the range, between the endpoints and the specific points in the range, and between the specific points can be used to generate one or more new numerical ranges, and these new numerical ranges should also be considered to be specifically disclosed herein.

[0041] When a component, element, or layer is referred to as being "on," "connected," "connected," or "coupled" to another element or layer, it may be directly on, connected, connected, or coupled to the other component, element, or layer, or there may be intervening elements or layers. Conversely, when an element is referred to as being directly on, "directly connected," "directly connected," or "directly coupled" to another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated enumerated items.

[0042] Although the terms first, second, third, etc. can be used to describe various steps, elements, components, regions, layers and / or sections in this article, these steps, elements, components, regions, layers and / or sections should not be limited by these terms unless otherwise specified. These terms can only be used to distinguish a step, element, component, region, layer or section from another step, element, component, region, layer or section. Unless clearly indicated in the context, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in this article. Therefore, the first step, element, component, region, layer or section discussed below can be referred to as the second step, element, component, region, layer or section without departing from the teaching of exemplary embodiments.

[0043] Unless otherwise specified, the terms used herein have the same meaning as commonly understood by those skilled in the art. If a term is defined herein and its definition is different from the commonly understood meaning in the art, the definition herein shall prevail.

[0044] As shown in FIG1 , the present disclosure provides a method for increasing the production of light aromatics, characterized in that the method comprises: allowing a gasoline heavy fraction to enter a lightening reactor and contact the lightening catalyst therein to cause a lightening reaction to occur, thereby obtaining a lightening reaction product; subjecting the lightening reaction product to product separation treatment; or allowing the lightening reaction product to enter a first reactor of a cracking reaction unit; wherein the lightening reactor is a dense phase fluidized bed reactor having a bed density of 180-700 kg / m 3 ; The catalyst activity of the light-weight reactor catalyst is 50-99, wherein the gasoline heavy fraction comprises a C9+ fraction.

[0045] Through the above technical solution, the present disclosure can efficiently convert heavy aromatics in heavy oil cracking products into light aromatics by subjecting heavy aromatics to light treatment. On the one hand, it can avoid the problems of high hydrogen consumption, harsh operating conditions and aromatics loss caused by the use of hydroprocessing to produce light aromatics; on the other hand, it can solve the problem of low-value heavy aromatics being difficult to utilize, and achieve efficient utilization of resources. In addition, the heavy fraction of gasoline is recycled in the light-weight reactor, wherein the light-weight reactor is a dense phase fluidized bed reactor, which can fully react the heavy fraction of gasoline, thereby further improving the yield of light aromatics. In addition, the method disclosed in the present disclosure can also produce low-carbon olefins as by-products, further improving the utilization rate of raw materials.

[0046] Optionally, the method further comprises: allowing the heavy oil feedstock, alone or together with the lightening reaction product, to enter the first reactor of the cracking reaction unit, and contacting the heavy oil feedstock with a cracking catalyst therein to carry out a cracking reaction to obtain a cracking reaction product; performing product separation treatment on the cracking reaction product or performing product separation treatment together with the lightening reaction product to obtain other products, light gasoline, a gasoline middle fraction and a gasoline heavy fraction; preferably, performing aromatics separation treatment on the gasoline middle fraction to obtain a benzene product, a toluene product and a xylene product.

[0047] In one embodiment, the heavy oil feedstock used in the present disclosure has an initial boiling point of 200-400°C, preferably 250-350°C; and a final boiling point of 450-600°C, preferably 500-550°C.

[0048] In a preferred embodiment, the heavy oil feedstock includes petroleum hydrocarbons and / or other mineral oils; wherein the petroleum hydrocarbons are selected from one of vacuum wax oil, atmospheric wax oil, coker wax oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, extracted oil and inferior recycled oil, or a mixture thereof; and the other mineral oils are selected from one of coal liquefaction oil, oil sand oil and shale oil, or a mixture thereof. In one embodiment, the cracking catalyst described in the present disclosure includes zeolite, inorganic oxide and optional clay; preferably, based on the total weight of the cracking catalyst, the content of the zeolite is 5-70% by weight, preferably 30-60% by weight; the content of the inorganic oxide is 1-95% by weight, preferably 30-70% by weight; and the content of the clay is 1-50% by weight, preferably 5-40% by weight. In a preferred embodiment, the zeolite of the cracking catalyst comprises a large-pore zeolite and an optional medium-pore zeolite; preferably, based on the total weight of the zeolite in the cracking catalyst, the content of the large-pore zeolite is 30-99 wt%, preferably 40-80 wt%; and the content of the medium-pore zeolite is 1-70 wt%, preferably 20-60 wt%.

[0049] In one embodiment, the lightening catalyst comprises zeolite, an inorganic oxide, and optionally clay; based on the total weight of the lightening catalyst, the content of the zeolite is 5-70% by weight, preferably 30-60% by weight; the content of the inorganic oxide is 1-95% by weight, preferably 30-70% by weight; and the content of the clay is 1-50% by weight, preferably 5-40% by weight.

[0050] The zeolite of the lightweight catalyst includes large-pore zeolite and medium-pore zeolite; based on the total weight of the zeolite in the lightweight catalyst, the content of large-pore zeolite is 50-99 weight%, preferably 60-80 weight%; the content of medium-pore zeolite is 1-50 weight%, preferably 20-40 weight%.

[0051] In the context of this disclosure, inorganic oxides do not include inorganic oxides in zeolites and clays.

[0052] In the context of the present disclosure, a large pore zeolite is a zeolite whose pore entrance is a 12-membered ring. A medium pore zeolite is a zeolite whose pore entrance is a 10-membered ring.

[0053] The zeolite includes large-pore zeolite and optional medium-pore zeolite; the medium-pore zeolite is preferably ZSM zeolite; and the large-pore zeolite is preferably one or more of β zeolite and Y zeolite.

[0054] Wherein, the inorganic oxide is silicon dioxide and / or aluminum oxide; and the clay is kaolin and / or halloysite.

[0055] In a preferred embodiment, the cracking catalyst and the light-weight catalyst further contain rare earth elements, respectively. The rare earth elements used in this disclosure are conventionally selected in the art and are not specifically required by this application. Preferably, rare earth elements are present in the zeolites of the cracking catalyst and the light-weight catalyst. Rare earth elements include at least one of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), yttrium (Y) and scandium (Sc). During modification, the rare earth elements are impregnated into the zeolite in the form of a solution. Solutions of rare earth elements include, but are not limited to, solutions of chlorides or nitrates. Further preferably, the rare earth elements in the cracking catalyst and the light-weight catalyst are mainly derived from beta-type zeolite and Y-type zeolite modified with rare earth elements. In this embodiment, adding rare earth elements to the cracking catalyst and the light-weighting catalyst can enhance the catalytic activity of the cracking catalyst and the light-weighting catalyst, thereby facilitating enhancement of the activity of the cracking reaction and the light-weighting reaction.

[0056] In a specific embodiment, the method for rare earth modification of Y-type zeolite includes: contacting a NaY molecular sieve with a mixed solution of a lanthanum nitrate solution and an ammonium salt, filtering, washing, and drying, and then performing a first calcination treatment to obtain a rare earth sodium Y-type molecular sieve; then slurrying the rare earth sodium Y-type molecular sieve and contacting it with an acid solution, filtering it and then mixing it with a lanthanum nitrate solution, and adjusting the pH value of the slurry to 5-6 with ammonia water, filtering or not filtering, drying, and performing a second calcination treatment to obtain a rare earth Y-type molecular sieve.

[0057] In one embodiment, the lightening catalyst and cracking catalyst used in the present disclosure may be the same or different depending on actual production needs.

[0058] In one embodiment, the method for preparing the cracking catalyst and the lightening catalyst comprises:

[0059] The inorganic oxide, clay and decationized water are uniformly stirred to form a slurry, wherein the solid content of the slurry is 10-50% by weight; the pH of the slurry is adjusted to 1-4 with an inorganic acid (such as hydrochloric acid, nitric acid, phosphoric acid or sulfuric acid), and an aging treatment is performed at this pH value, wherein the aging treatment temperature is 20-80°C and the time is 0-2 hours; then the inorganic oxide is added and stirred for 0.5-1.5 hours to form a colloid, and zeolite is added thereto to form a catalyst slurry, wherein the zeolite content is 5-70% by weight, the clay content is 1-50% by weight, and the inorganic oxide content is 1-95% by weight, based on the total weight of the solid phase in the catalyst slurry, wherein the content of large-pore zeolite in the zeolite is 30-99% by weight and the content of medium-pore zeolite is 1-70% by weight, based on the total weight of the zeolite; and the stirring is continued and the colloid is spray-dried to form a microsphere catalyst. The microsphere catalyst is then calcined at 400-600° C. for 0.5-2 hours, and then washed with ammonium sulfate at 30-80° C. (washing with ammonium sulfate here and below means using solid ammonium sulfate dissolved in deionized water and then mixing it evenly with the microsphere catalyst for washing) until the sodium oxide content is less than 0.25% by weight. It is then rinsed with deionized water and filtered, and then dried at 100-200° C. to obtain a cracking / lightening catalyst; wherein the weight of ammonium sulfate: the weight of the microsphere catalyst: the weight of water = (0.1-1):1:(5-15).

[0060] In one embodiment, the cracking reaction unit used in the present disclosure includes a first reactor, a light-weighting reactor 13, a regenerator 18 and a settler 16; wherein, the number of regenerators 18 and settlers 16 can be flexibly selected according to actual production needs. For example, the number of regenerators 18 and settlers 16 used in this application can be independently 1 or 2.

[0061] In one embodiment, the reactor type of the lightweighting reactor 13 is a dense phase fluidized bed reactor. In one embodiment, the first reactor is a riser reactor, a fluidized bed reactor, or a combination of the two. According to a specific embodiment, the reactor type of the first reactor is a dense phase fluidized bed reactor, a dilute phase transport bed reactor, or a composite reactor consisting of a dense phase fluidized bed reactor and a dilute phase transport bed reactor. The reactor type of the dense phase fluidized bed reactor used in the present disclosure is a bubbling bed reactor, a turbulent bed reactor, or a fast bed reactor; the dilute phase transport bed reactor is a riser reactor.

[0062] In a preferred embodiment, the first reactor is a combination of a riser reactor 14 and a fluidized bed reactor 15 , wherein the riser reactor 14 and the fluidized bed reactor 15 are arranged in series, and the fluidized bed reactor 15 is located downstream of the riser reactor 14 .

[0063] The bed density of the dense phase fluidized bed reactor is preferably 300-500 kg / m 3 ; The bed linear velocity is 0.1-3m / s, preferably 0.4-2m / s.

[0064] The first reactor and the lightening reactor 13 can be arranged in parallel or in series. It should be noted that the connection method of the first reactor and the lightening reactor 13 can be selected according to the cracking catalyst and the lightening catalyst.

[0065] In one embodiment, when the lightening catalyst and the cracking catalyst are the same, there is no need to consider the catalyst mixing problem. Therefore, the cracking reaction unit includes a regenerator 18, a settler 16, a riser reactor 14, a fluidized bed reactor 15 and a lightening reactor 13, and the first reactor and the lightening reactor 13 are arranged in series.

[0066] In one embodiment, when the lightening catalyst and the cracking catalyst are different, the cracking catalyst and the lightening catalyst need to be separated. Therefore, the cracking reaction unit includes two regenerators, namely a cracking regenerator 46 and a lightening regenerator 47, two settlers, namely a cracking settler 40 and a lightening settler 41, a riser reactor 14, a fluidized bed reactor 15 and a lightening reactor 13, wherein the riser reactor 14 and the fluidized bed reactor 15 are connected in series, and the first reactor is arranged in parallel with the lightening reactor 13.

[0067] In a specific embodiment, when the first reactor and the lightening reactor 13 are arranged in series, the first reactor is arranged downstream of the lightening reactor 13 so that the product obtained by the lightening reactor 13 can enter the first reactor to continue the reaction.

[0068] The first reactor is connected in series with the settler 16 so that the material obtained by the reaction in the first reactor can enter the settler 16 for separation. In addition, the first reactor and the settler 16 can be coaxially arranged or separated according to actual use. Preferably, the first reactor and the settler 16 are coaxially arranged.

[0069] According to actual production needs, the first reactor and the lightweight reactor 13 can be coaxially arranged or separated, that is, non-coaxially arranged.

[0070] In one embodiment, when the first reactor and the light-weight reactor 13 are arranged in series, the reaction mixture of the fluidized bed reactor 15 is separated by a settler 16 to obtain a catalyst to be regenerated and the cracking reaction product; the catalyst to be regenerated enters a regenerator 18 for regeneration treatment to obtain a regenerated catalyst; the regenerated catalyst is returned to the riser reactor 14 through a first regeneration inclined pipe 20 and / or the regenerated catalyst is returned to the light-weight reactor 13 through a second regeneration inclined pipe 19.

[0071] In a specific embodiment, as shown in FIG2 , when the first reactor and the light-weight reactor 13 are coaxially arranged, a regenerated catalyst outlet is provided on the side wall of the settler 16, a regenerated catalyst inlet, a first regenerated agent outlet, and a second regenerated agent outlet are provided on the side wall of the regenerator 18 (although not shown in the figure, the regenerator 18 may be provided with an overflow hopper, and a fresh agent inlet may be provided in the regenerator overflow hopper), a first regenerated agent inlet and a heavy oil feedstock inlet are provided on the riser reactor 14, and a second regenerated agent inlet, a gasoline heavy fraction inlet, a fresh agent 23 inlet, and a pre-lifting medium inlet are provided on the light-weight reactor 13; The outlet of the catalyst to be regenerated of the settler 16 is connected to the inlet of the catalyst to be regenerated of the regenerator through the inclined pipe 17; the first regeneration agent outlet of the regenerator 18 is connected to the first regeneration agent inlet of the riser reactor 14 through the first regeneration inclined pipe 20, and the second regeneration agent outlet of the regenerator 18 is connected to the second regeneration agent inlet of the lightening reactor 13 through the second regeneration inclined pipe 19; the heavy oil feedstock inlet of the riser reactor 14 is connected to the heavy oil feedstock source; the pre-lifting medium inlet of the lightening reactor 13 is used to be connected to the pre-lifting medium source, and the fresh agent inlet of the lightening reactor 13 is used to be connected to the fresh agent source.

[0072] A fresh agent 22 inlet is provided on the second regeneration inclined tube 19 , and the fresh agent inlet is used to communicate with a fresh agent source, so that the fresh agent can enter the lightweighting reactor 13 through the second regeneration inclined tube 19 .

[0073] In order to flexibly adjust the flow rates of the feed and discharge of the regenerator 18 , flow regulating valves are provided on the inclined pipe to be regenerated 17 , the first regeneration inclined pipe 20 and the second regeneration inclined pipe 19 .

[0074] In another specific embodiment, as shown in FIG3 , when the first reactor and the light-reaction reactor 13 are separately arranged (i.e., non-coaxially), an outlet for the catalyst to be regenerated is provided on the side wall of the settler 16, an inlet for the catalyst to be regenerated, a first regeneration agent outlet, and a second regeneration agent outlet are provided on the side wall of the regenerator 18 (although not shown in the figure, the regenerator may be provided with an overflow bucket, and a fresh agent inlet may be provided in the regenerator overflow bucket), a first regeneration agent inlet, a light-reaction product inlet, a heavy oil feedstock inlet, and a pre-lifting medium inlet are provided on the riser reactor 14, and a second regeneration agent inlet, a gasoline heavy fraction inlet, and a light-reaction product outlet are provided on the light-reaction reactor 13; the outlet for the catalyst to be regenerated in the settler 16 is provided through the outlet for the catalyst to be regenerated. The regeneration inclined pipe 17 is connected to the catalyst inlet to be regenerated of the regenerator 18; the first regeneration agent outlet of the regenerator 18 is connected to the first regeneration agent inlet of the riser reactor 14 through the first regeneration inclined pipe 20, and the second regeneration agent outlet of the regenerator is connected to the second regeneration agent inlet of the lightening reactor 13 through the second regeneration inclined pipe 19; the lightening reaction product outlet of the lightening reactor 13 is connected to the lightening reaction product inlet of the riser reactor 14; the heavy oil feedstock inlet of the riser reactor 14 is connected to the heavy oil feedstock source; the pre-lifting medium inlet of the riser reactor 14 is used to be connected to the pre-lifting medium source; the gasoline heavy fraction inlet of the lightening reactor 13 is connected to the gasoline heavy fraction outlet of the product separation device 4.

[0075] A fresh agent inlet is provided at the bottom of the second regeneration inclined tube 19 and / or the lightweight reactor 13 and / or the regenerator overflow bucket, and the fresh agent inlet is connected to the fresh agent source so that the fresh agent can enter the lightweight reactor 13.

[0076] In one embodiment, if the cracking catalyst and the lightening catalyst are different, the first reactor and the lightening reactor 13 need to be separately provided. Furthermore, the first reactor is connected in series with the cracking settler 40 so that the material obtained by the reaction in the first reactor can enter the cracking settler 40. The lightening reactor 13 is integrated with the lightening settler 41 so that the material obtained by the reaction in the lightening reactor 13 can enter the lightening settler 41. Furthermore, the first reactor and the lightening reactor 13 are each equipped with a regenerator.

[0077] In this embodiment, the outlet material of the fluidized bed reactor 15 is separated by a cracking settler 40 to obtain a regenerated cracking catalyst and the cracking reaction product; the regenerated cracking catalyst enters a cracking regenerator 46 for regeneration to obtain a regenerated cracking catalyst; the regenerated cracking catalyst is returned to the riser reactor 14 through a third regeneration inclined pipe 43; the post-reaction mixture of the lightening reactor 13 is separated by a lightening settler 41 to obtain a regenerated lightening catalyst and the lightening reaction product; the regenerated lightening catalyst enters a lightening regenerator 47 for regeneration to obtain a regenerated lightening catalyst; and the regenerated lightening catalyst is returned to the lightening reactor 13 through a fourth regeneration inclined pipe 45.

[0078] In a specific embodiment, as shown in Figure 4, a spent catalyst outlet is provided on the side wall of the cracking settler 40 and a cracking reaction product outlet is provided on the top; the riser reactor 14 includes a pre-lifting medium inlet, a heavy oil feedstock inlet and a third regeneration agent inlet; the cracking regenerator 46 includes a spent catalyst inlet and a third regeneration agent outlet; the spent catalyst outlet of the cracking settler 40 is connected to the spent catalyst inlet of the cracking regenerator 46 through a cracking spent catalyst inclined pipe 42; the third regeneration agent outlet of the cracking regenerator 46 is connected to the third regeneration agent inlet of the riser reactor 14 through a third regeneration inclined pipe 43; the pre-lifting medium inlet of the riser reactor 14 is used to communicate with a pre-lifting medium source; the heavy oil feedstock inlet of the riser reactor 14 is used to communicate with a heavy oil feedstock source.

[0079] A spent catalyst outlet is provided on the side wall of the lightening settler 41, and a lightening reaction product outlet is provided on the top. The lightening reactor 13 includes a pre-lift medium inlet, a gasoline heavy fraction inlet, and a fourth regeneration agent inlet. The lightening regenerator 47 includes a spent catalyst inlet and a fourth regeneration agent outlet (although not shown in the figure, the lightening regenerator 47 may be provided with an overflow hopper, and a fresh catalyst inlet may be provided in the regenerator overflow hopper). The spent catalyst outlet of the lightening settler 41 is connected to the spent catalyst inlet of the lightening regenerator 47 via a lightening spent catalyst inclined pipe 44. The fourth regeneration agent outlet of the lightening regenerator 47 is connected to the fourth regeneration agent inlet of the lightening reactor 13 via a fourth regeneration inclined pipe 45. The pre-lift medium inlet of the lightening reactor 13 is used to communicate with a pre-lift medium source. The gasoline heavy fraction inlet of the lightening reactor 13 is used to communicate with the gasoline heavy fraction outlet of the product separation device 4.

[0080] The cracking reaction product 49 outlet pipeline of the cracking settler 40 and the light reaction product 48 outlet pipeline of the lightening settler 41 are merged into a cracking reaction product bus, so that the mixed materials can enter the product separation device 4 .

[0081] Among them, a fresh agent inlet is provided on the fourth regeneration inclined tube 45 and / or the bottom of the lightweight reactor 13 and / or the regenerator overflow bucket of the lightweight regenerator 47, and the above-mentioned fresh agent inlet is connected to the fresh agent source so that the fresh agent can enter the lightweight reactor 13.

[0082] In one embodiment, a steam inlet is further provided at the inlet of the riser reactor 14 for communicating with a steam source so that steam can enter the riser reactor 14 .

[0083] In one embodiment, to further enhance the separation effect, cyclone separators are provided above the settler 16, the regenerator 18, the cracking settler 40, the cracking regenerator 46, the lightweight settler 41, and the lightweight regenerator 47. The cyclone separators used in this disclosure are conventional in the art and are not required by this application. The number of cyclone separator stages can be flexibly selected based on actual production needs. Preferably, the number of cyclone separator stages is two.

[0084] Among them, an air collecting chamber is provided at the top of the settler 16, the cracking settler 40 and the lightening settler 41. The inlet of the air collecting chamber is connected with the cracking reaction product outlet of the cyclone separator, and the outlet of the air collecting chamber is used to be connected with the cracking reaction product outlet, so that the cracking reaction product can be buffered by the air collecting chamber and then exit the system through the outlet.

[0085] An oxygen-containing gas distributor is further provided inside the regenerator 18 , the cracking regenerator 46 and the lightening regenerator 47 , and the inlet of the oxygen-containing gas distributor extends to the outside of each regenerator to form an oxygen-containing gas inlet.

[0086] In one embodiment, a light gasoline inlet may be provided at the lower portion of the fluidized bed reactor 15 so that the light gasoline can be returned to the cracking reaction unit for further reaction.

[0087] In one embodiment, the pre-lifting medium used in the present disclosure is a conventional choice in the art, and this application does not make any special requirements. For example, the pre-lifting medium can be water vapor and / or dry gas.

[0088] In one embodiment, the method for performing a cracking reaction using the apparatus of Figure 2 includes: allowing the fresh agent 23, the second regenerated catalyst, and the gasoline heavy fraction 7 to enter the lightening reactor 13 under the action of a pre-lifting medium to carry out a lightening reaction to obtain a lightening reaction product; allowing the lightening reaction product, the first regenerated catalyst, and the heavy oil feedstock 1 to enter the first reactor for a cracking reaction to obtain a mixture of cracking reaction products and the catalyst to be regenerated, wherein most of the catalyst to be regenerated moves downward under the action of gravity, and the cracking reaction products and a small portion of the catalyst to be regenerated in the mixture move upward and enter a cyclone separator for separation, so that the small portion of the catalyst to be regenerated returns to the settler 16, and the cracking reaction product 3 exits the settler 16 through the gas collecting chamber. The catalyst to be regenerated is passed through the inclined tube 17 into the regenerator 18 and is regenerated under the action of an oxygen-containing gas (the inlet of which is indicated by an arrow) to obtain a regenerated catalyst and a regenerated flue gas 21, which is then discharged. The regenerated catalyst is divided into a first regenerated catalyst and a second regenerated catalyst, the first regenerated catalyst is returned to the riser reactor 14 through the first regeneration inclined tube 20, and the second regenerated catalyst is returned to the lightweight reactor 13 after being mixed with the fresh agent 22 through the second regeneration inclined tube 19.

[0089] In another embodiment, the method for carrying out a cracking reaction using the apparatus of FIG3 includes: allowing the light reaction product, the first regenerated catalyst, and the heavy oil feedstock 1 to enter the first reactor under the action of a pre-lifting medium for a cracking reaction to obtain a mixture of cracking reaction products and the catalyst to be regenerated, wherein the vast majority of the catalyst to be regenerated moves downward under the action of gravity, and the cracking reaction product and a small portion of the catalyst to be regenerated in the mixture move upward and enter a cyclone separator for separation, so that the small portion of the catalyst to be regenerated returns to the settler 16, and the cracking reaction product 3 exits the settler 16 through the gas collecting chamber. The catalyst to be regenerated is passed through the inclined tube 17 into the regenerator 18, and is regenerated under the action of an oxygen-containing gas (the inlet of which is indicated by an arrow) to obtain a regenerated catalyst and a regenerated flue gas 21, and the regenerated flue gas 21 is discharged; the regenerated catalyst is divided into a first regenerated catalyst and a second regenerated catalyst, and the first regenerated catalyst is returned to the riser reactor 14 through the first regeneration inclined tube 20; the second regenerated catalyst is passed through the second regeneration inclined tube 19 into the lightening reactor 13, and is mixed with the gasoline heavy fraction 7 and the fresh agent for reaction to obtain a lightening reaction product, and the lightening reaction product is returned to the riser reactor 14 through the outlet pipeline.

[0090] In another embodiment, a method for conducting a cracking reaction using the apparatus of FIG. 4 includes: allowing a heavy oil feedstock 1 and a third regenerated catalyst to enter a riser reactor 14 under the action of a pre-lifting medium for a cracking reaction, thereby producing a mixture containing a raw cracking catalyst and cracking reaction products; allowing the majority of the raw cracking catalyst in the mixture to flow downward under the action of gravity, while the cracking reaction products and a small portion of the raw cracking catalyst in the mixture flow upward and enter a cyclone separator for separation, thereby returning the small portion of the raw cracking catalyst to a cracking settler 40, and allowing the cracking reaction products 49 to exit the cracking settler 40 through a gas collecting chamber. The raw cracking catalyst is then passed through a cracking inclined pipe 42 into a cracking regenerator 46, where it is regenerated under the action of an oxygen-containing gas (the inlet of which is indicated by an arrow), producing a third regenerated catalyst and regenerated flue gas 21; the regenerated flue gas 21 is discharged, and the third regenerated catalyst is returned to the riser reactor 14 through a third regeneration inclined pipe 43. The fresh agent 23, the fourth regenerated catalyst, and the gasoline heavy fraction 7 are introduced into the lightening reactor 13 under the action of the pre-lifting medium to undergo a lightening reaction, thereby obtaining a mixture containing lightening reaction products and a lightening catalyst to be regenerated. The vast majority of the lightening catalyst to be regenerated in the mixture moves downward under the action of gravity, while the lightening reaction products and a small portion of the lightening catalyst to be regenerated in the mixture move upward and enter a cyclone separator for separation, so that a small portion of the lightening catalyst to be regenerated returns to the lightening settler 41, and the lightening reaction products 48 exit the system through the gas collecting chamber. The regenerated light-catalyst passes through the regenerated light-catalyst inclined pipe 44 and enters the light-catalyst regenerator 47, and is regenerated under the action of an oxygen-containing gas (the inlet of which is indicated by an arrow) to obtain a fourth regenerated catalyst and a regenerated flue gas 21; the regenerated flue gas 21 is discharged, and the fourth regenerated catalyst is mixed with the fresh agent 22 through the fourth regeneration inclined pipe 45 and then returned to the light-catalyst reactor 13; the cracking reaction product 49 and the light-catalyst reaction product 48 are mixed and then enter the product separation device 4.

[0091] In the above embodiment, the fresh agent is a fresh cracking catalyst or a light-weight catalyst. When the cracking catalyst and the light-weight catalyst are the same, the fresh agent can be a fresh cracking catalyst or a light-weight catalyst; when the cracking catalyst and the light-weight catalyst are different, the fresh agent is a fresh light-weight catalyst.

[0092] In one embodiment, the method further includes adding a fresh agent to the lightening reactor 13; wherein the ratio of the amount of fresh agent added to the amount of catalyst circulation in the cracking reaction unit is less than 0.2, preferably 0.02-0.18, and more preferably 0.05-0.12.

[0093] In which, when the lightening reactor is connected in parallel with the first reactor, the catalyst circulation amount in the cracking reaction unit is based on the catalyst circulation amount in the catalytic cracking reaction system (catalytic cracking reaction and regeneration cycle) and the lightening reaction system (lightening reaction and regeneration cycle).

[0094] Wherein, in the case where the light-treatment reactor and the first reactor are connected in series, the circulation amount of the catalyst in the catalytic reaction unit is the circulation amount of the catalyst in the light-treatment reaction, catalytic cracking reaction and regeneration system.

[0095] In this context, the catalyst circulation amount refers to the mass of catalyst transported from the reaction (or regeneration) system to the regeneration (or reaction) system by pneumatic transport per unit time, also known as the catalyst circulation rate.

[0096] When fresh catalyst is added, an amount of catalyst corresponding to the amount of fresh catalyst added is removed from the corresponding regenerator to maintain a constant amount of catalyst in the cracking reaction unit. When the light-weight reactor and the first reactor are arranged in series, an amount of catalyst corresponding to the amount of fresh catalyst added is removed from the regenerator. When the light-weight reactor and the first reactor are arranged in parallel, an amount of catalyst corresponding to the amount of fresh catalyst added is removed from the light-weight regenerator.

[0097] In one embodiment, the catalyst activity disclosed herein refers to the micro-reaction activity index measured by the method of NB / SH / T 0952-2017.

[0098] In one embodiment, the reaction conditions of the cracking reaction include: a reaction temperature of 520-720°C, preferably 550-700°C, and more preferably 600-640°C; a reaction time of 1-10s, preferably 1.5-6s, and more preferably 2-4s; a reaction pressure of 130-450kPa (absolute pressure), preferably 150-400kPa (absolute pressure), and more preferably 180-300kPa (absolute pressure); a catalyst-oil ratio of (1-100):1, preferably (10-50):1, and more preferably (15-20):1; and a catalyst activity of 40-90, preferably 50-80, and more preferably 55-70.

[0099] In one embodiment, the reaction conditions of the lightening reaction include: a reaction temperature of 530-730°C, preferably 560-680°C, and more preferably 610-650°C; a reaction time of 1-20s, preferably 3-15s, and more preferably 3.5-10s; a reaction pressure of 130-450kPa (absolute pressure), preferably 150-400kPa (absolute pressure), and more preferably 180-300kPa (absolute pressure); a catalyst-oil ratio of (1-100):1, preferably (5-30):1, and more preferably (15-25):1; and a catalyst activity of more preferably 60-90.

[0100] In one embodiment, the product separation and processing apparatus and method disclosed in the present disclosure are conventionally selected in the art, and the present application does not impose any requirements. It is only necessary that the cracking reaction products can be separated into light gasoline, gasoline middle fraction, gasoline heavy fraction and other products. For example, the product separation processing of the present application includes: subjecting the cracking reaction products to a first separation to obtain the light gasoline, heavy gasoline and the other products; subjecting the heavy gasoline to a second separation to obtain the gasoline middle fraction and the gasoline heavy fraction.

[0101] In the context of the present invention, other products primarily comprise H2-C4 gaseous components, diesel, and heavy oil fractions; light gasoline primarily comprises C4-C5 components; middle gasoline fractions primarily comprise C6-C8 components; and heavy gasoline fractions primarily comprise C9+ components. C9+ components, also known as C9+ fractions, refer to fractions with 9 or more carbon atoms. Preferably, the heavy gasoline fraction contains a significant amount of aromatic hydrocarbons, e.g., ≥40% aromatic hydrocarbons, preferably ≥50% to 99% aromatic hydrocarbons.

[0102] Among them, the initial boiling point of the light gasoline is 20-40°C; the distillation cut point between the light gasoline and the heavy gasoline is 80-100°C; the distillation cut point between the gasoline middle distillate and the gasoline heavy distillate is 120-150°C, the distillation cut point between the gasoline heavy distillate and the diesel distillate is 190-220°C, and the distillation cut point between diesel and heavy oil is 330-370°C.

[0103] In one embodiment, the apparatus and method for separation and treatment of aromatics are conventionally selected in the art, and this application does not impose any requirements. It is only necessary to be able to separate the gasoline middle fraction into benzene products, toluene products, and xylene products. For example, aromatic extraction technology is used for separation, and the aromatic residue oil can be returned to the cracking reaction unit to continue the reaction. Its recycling position can be the same as that of light gasoline, that is, the lower part of the fluidized bed reactor 15.

[0104] In one embodiment, the method further includes returning part or all of the light gasoline to the cracking reaction unit 2 for reaction. The return position of the light gasoline can be flexibly selected according to actual production needs. The ratio of the weight of the light gasoline returned to the catalytic cracking reaction unit 2 to the total weight of the light gasoline needs to be flexibly selected according to actual production needs, and this application does not make any special requirements.

[0105] Example

[0106] The following examples will further illustrate the present invention, but are not intended to limit the present invention. The heavy oil raw material used in the examples and comparative examples is heavy oil, wherein the properties of the heavy oil are shown in Table 1.

[0107] Table 1 Properties of heavy oil feedstock

[0108] Preparation Example 1

[0109] The preparation method of rare earth Y molecular sieve (REY) comprises: contacting a NaY molecular sieve with a mixed solution of a lanthanum nitrate solution and ammonium sulfate, filtering, washing with water, and drying, and then performing a first roasting treatment to obtain a rare earth sodium Y molecular sieve; then slurrying the rare earth sodium Y molecular sieve and contacting it with an acid solution, filtering it and then mixing it with a lanthanum nitrate solution, adjusting the pH value of the slurry to 6 with ammonia water, filtering or not filtering, drying, and performing a second roasting treatment to obtain a rare earth Y molecular sieve (REY).

[0110] The method for preparing Catalyst C1 comprises: mixing aluminum sol and kaolin, and preparing the mixture into a slurry with decationized water having a solid content of 40% by weight, stirring the mixture uniformly, adjusting the pH of the slurry to 4 with hydrochloric acid, nitric acid, phosphoric acid, or sulfuric acid, and maintaining the pH value. After aging at 60°C for 1 hour, the aluminum sol is added, stirring for 1 hour to form a colloid, and ZSM-5 and rare earth Y molecular sieve (REY) are added to form a catalyst slurry (solid content of 35% by weight), wherein the weight ratio of ZSM-5 molecular sieve: weight of REY: weight of kaolin: weight of aluminum sol is 15:35:34:16. After continued stirring, the mixture is spray-dried to form a microsphere catalyst. The microsphere catalyst is then calcined at 500°C for 1 hour and then washed with ammonium sulfate at 60°C (washing with ammonium sulfate herein and hereinafter means washing the microsphere catalyst using solid ammonium sulfate dissolved in deionized water and then mixed uniformly with the microsphere catalyst). The mixture was washed with deionized water, filtered, and dried at 110° C. to obtain catalyst C1.

[0111] Preparation Example 2

[0112] The preparation method of rare earth Y molecular sieve (REY) is the same as that of Preparation Example 1;

[0113] The method for preparing catalyst C2 includes: mixing aluminum sol and kaolin, and preparing them into a slurry with a solid content of 40% by weight with decationized water, stirring them evenly, adjusting the pH of the slurry to 4 with hydrochloric acid, nitric acid, phosphoric acid or sulfuric acid, maintaining the pH value, aging at 60°C for 1 hour, adding aluminum sol, stirring for 1 hour to form a colloid, adding ZSM-5 and rare earth Y molecular sieve (REY) to form a catalyst slurry (solid content of 35% by weight), wherein the weight of ZSM-5: weight of REY: weight of kaolin: weight of aluminum sol = 5:45:34:16, continuing stirring and spray drying to prepare a microsphere catalyst. The microsphere catalyst was then calcined at 500°C for 1 hour and then washed with ammonium sulfate at 60°C (wherein the weight of ammonium sulfate: the weight of the microsphere catalyst: the weight of water = 0.5:1:10) until the sodium oxide content was less than 0.25% by weight. The catalyst was then rinsed with deionized water and filtered, and then dried at 110°C to obtain catalyst C2.

[0114] Test Example 1

[0115] The test is carried out according to the 460°C micro-reaction activity index determination method in NB / SH / T 0952-2017, and the obtained micro-reaction activity index is the catalytic activity of the catalyst.

[0116] Example 1

[0117] The method for catalytically cracking gasoline and then converting it to increase the production of light aromatics using the system of FIG1 and the cracking reaction unit 2 of FIG2 includes:

[0118] The lightening reaction product, the first regenerated catalyst, and the heavy oil feedstock 1 from the lightening reactor are introduced into the first reactor for a cracking reaction, thereby obtaining a mixture containing the cracking reaction product and the catalyst to be regenerated. The majority of the catalyst to be regenerated flows downward under the action of gravity, while the cracking reaction product and a small portion of the catalyst to be regenerated in the mixture flow upward and enter a cyclone separator for separation, allowing the small portion of the catalyst to be regenerated to return to the settler 16. The cracking reaction product exits the settler 16 through the gas collecting chamber. The regenerated catalyst is introduced into the regenerator 18 through the regeneration inclined pipe 17 and is regenerated under the action of an oxygen-containing gas to obtain a regenerated catalyst and regenerated flue gas 21, which is then discharged. The regenerated catalyst is separated into a first regenerated catalyst and a second regenerated catalyst. The first regenerated catalyst is returned to the first reactor via the first regeneration inclined pipe 20, while the second regenerated catalyst is returned to the lightening reactor 13 via the second regeneration inclined pipe 19.

[0119] The cracking reaction product is passed into a product separation unit 4 for a first separation to obtain the other products 8, light gasoline 5, and heavy gasoline. The heavy gasoline is subjected to a second separation to obtain a gasoline middle distillate 6 and a gasoline heavy distillate 7, wherein the initial boiling point of the light gasoline 5 is 30°C, the cut point between the light gasoline 5 and the heavy gasoline is 75°C, and the cut point between the gasoline middle distillate 6 and the gasoline heavy distillate 7 is 145°C. The gasoline middle distillate 6 is passed into an aromatics separation unit 9 for aromatics separation treatment to obtain a benzene product 10, a toluene product 11, and a xylene product 12. The fresh agent, the second regenerated catalyst, and the gasoline heavy distillate 7 are passed into a lightening reactor 13 under the action of a pre-lifting medium (steam) to carry out a lightening reaction to obtain a lightening reaction product. The ratio of the weight of the fresh agent to the catalyst circulation amount in the cracking reaction unit is 0.02:1. The other products are further separated to obtain dry gas, ethylene, liquefied petroleum gas, propylene, and gasoline.

[0120] The reaction conditions and product properties are shown in Table 2.

[0121] Example 2

[0122] The method for catalytic cracking gasoline reconversion to increase the production of light aromatics is the same as in Example 1, except that the reaction temperature for the lightening reaction is 620° C. The reaction conditions and product properties are shown in Table 2.

[0123] Example 3

[0124] The method for catalytic cracking gasoline reconversion to increase the production of light aromatics was the same as in Example 1, except that the catalyst-to-oil ratio in the lightening reaction was 15:1. The reaction conditions and product properties are shown in Table 2.

[0125] Example 4

[0126] The method for catalytically cracking gasoline to increase the yield of light aromatics was the same as in Example 1, except that the cracking reaction unit shown in Figure 4 was used for the cracking reaction, ensuring that the catalyst used in the cracking reaction was entirely derived from C1 regenerated catalyst. The reaction conditions and product properties are shown in Table 2.

[0127] Example 5

[0128] The method for catalytic cracking gasoline reconversion to increase light aromatics production was the same as in Example 1, except that the valve on the first regeneration inclined tube 20 was closed, ensuring that the catalyst for the cracking reaction was entirely derived from the C1 spent catalyst. The reaction conditions and product properties are shown in Table 2.

[0129] Example 6

[0130] The method for catalytically cracking gasoline to increase the yield of light aromatics was the same as in Example 1, except that the cracking reaction unit of Figure 4 was used for the cracking reaction, and the catalyst for the lightening reaction was replaced with an equal weight of catalyst C2. The reaction conditions and product properties are shown in Table 2.

[0131] Example 7

[0132] The method for catalytic cracking gasoline reconversion to increase the production of light aromatics is the same as that in Example 1, except that the bed density of the dense phase fluidized bed reactor is 250 kg / m 3 The reaction conditions and product properties are shown in Table 2.

[0133] Example 8

[0134] The method for catalytic cracking gasoline reconversion to increase the production of light aromatics is the same as in Example 1, except that the light gasoline is not returned to the cracking reaction unit 2 for further reaction. The reaction conditions and product properties are shown in Table 2.

[0135] Example 9

[0136] The method for catalytic cracking gasoline and then converting it to increase the production of light aromatics is the same as in Example 1, except that the cracking reaction conditions are different. The reaction conditions and product properties are shown in Table 3.

[0137] Example 10

[0138] The method for catalytic cracking gasoline reconversion to increase the production of light aromatics was the same as in Example 1, except that no freshener was added during the lightening reaction in the lightening reactor. The reaction conditions and product properties are shown in Table 3.

[0139] Example 11

[0140] The method for catalytic cracking gasoline reconversion to increase the yield of light aromatics was the same as in Example 1, except that the ratio of the weight of fresh catalyst to the recycled amount of catalyst used in the cracking reaction unit was 0.16:1. The reaction conditions and product properties are shown in Table 3.

[0141] Example 12

[0142] The method for catalytic cracking gasoline reconversion to increase the production of light aromatics is the same as that in Example 1, except that the bed density of the dense phase fluidized bed is 650 kg / m 3 The reaction conditions and product properties are shown in Table 3.

[0143] Example 13

[0144] The method for catalytic cracking gasoline and then converting it to increase the production of light aromatics is the same as in Example 1, except that the cracking reaction unit shown in Figure 3 is used for the cracking reaction. The reaction conditions and product properties are shown in Table 3.

[0145] Comparative Example 1

[0146] The method for catalytic cracking gasoline reconversion to increase light aromatics is the same as in Example 1, except that neither the light gasoline nor the heavy gasoline fraction is returned to the cracking reaction unit 2 for further reaction. The reaction conditions and product properties are shown in Table 3.

[0147] Comparative Example 2

[0148] The method for catalytic cracking gasoline reconversion to increase light aromatics was the same as in Example 1, except that the cracking catalyst and the lightening catalyst were replaced by equal weights of CDOS. The CDOS catalytic cracking catalyst was purchased from Changling Catalyst Company. The reaction conditions and product properties are shown in Table 3.

[0149] Comparative Example 3

[0150] The method for catalytically cracking gasoline for reconversion to increase the production of light aromatics is the same as in Example 1, except that the cracking reaction is performed using the cracking reaction unit shown in Figure 5 , i.e., the lightening reactor is riser reactor 24, and the regenerated catalyst is returned to riser reactor 24 via regeneration inclined conduit 50. Reaction conditions and product properties are shown in Table 3.

[0151] Table 2 Reaction conditions and product properties in the examples

[0152] Table 3 Reaction conditions and product properties in Examples and Comparative Examples

[0153] As can be seen from the table, according to the comparison of the data of Examples 1-13 and Comparative Examples 1-3, it can be seen that the technical solution disclosed in the present invention can avoid the problems of high hydrogen consumption, harsh operating conditions and aromatic hydrocarbon loss caused by the use of hydroprocessing to produce light aromatics. According to the comparison of the data in Example 1, Example 2 and Example 3, the lightening reaction of the present application performs non-hydrogen catalytic cracking on the heavy fraction of gasoline at a temperature of 610-650°C and a catalyst-oil ratio of (15-25):1, and can obtain a higher BTX yield; According to the comparison of the data in Example 1, Example 6 and Comparative Example 2, it can be seen that when the catalytic activity of the catalyst in the lightening reactor meets 50-99, a higher BTX yield can be obtained; According to the comparison of the data in Example 1, Example 7 and Comparative Example 3, the bed density of the lightening reactor is 180-700kg / m 3 , can obtain higher BTX yield, and the bed density of dense phase fluidized bed reactor is 300-500kg / m 3 , which can further improve the yield of BTX; according to the comparison of the data in Example 1 and Example 8, it can be seen that returning the light gasoline to the cracking reaction unit for recycling can further improve the yield of BTX; according to the comparison of the data in Example 1, Example 10 and Example 11, it can be seen that adding a fresh agent during the lightening reaction can obtain a higher BTX yield.

[0154] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0155] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0156] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for increasing the production of light aromatics, characterized in that: The method includes: The heavy fraction of gasoline is allowed to enter a light-weighting reactor and contact with a light-weighting catalyst therein to cause a light-weighting reaction to occur, thereby obtaining a light-weighting reaction product; performing product separation treatment on the lightening reaction product; or, Allowing the lightening reaction product to enter the first reactor of the cracking reaction unit; The lightweight reactor is a dense phase fluidized bed reactor, and the bed density of the dense phase fluidized bed reactor is 180-700 kg / m 3 ; The catalyst activity of the catalyst in the lightening reactor is 50-99, The gasoline heavy fraction comprises a C9+ fraction.

2. The method according to claim 1, characterized in that The method further comprises: The heavy oil feedstock, alone or together with the lightening reaction product, enters the first reactor of the cracking reaction unit, and contacts with the cracking catalyst therein to cause a cracking reaction, thereby obtaining a cracking reaction product; The cracking reaction product is subjected to product separation treatment or is subjected to product separation treatment together with the lightening reaction product to obtain light gasoline, gasoline middle fraction, gasoline heavy fraction and other products; Preferably, the gasoline middle fraction is subjected to aromatic separation treatment to obtain a benzene product, a toluene product and a xylene product.

3. The method according to claim 2, characterized in that The heavy oil feedstock includes petroleum hydrocarbons and / or other mineral oils; The petroleum hydrocarbon is selected from one of vacuum wax oil, atmospheric wax oil, coker wax oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, extracted oil and inferior recycled oil, or a mixture thereof; The other mineral oil is selected from one of coal liquefaction oil, oil sand oil and shale oil or a mixture thereof; or The initial distillation point of the heavy oil raw material is 200-400°C, preferably 250-350°C; the final distillation point is 450-600°C, preferably 500-550°C.

4. The method according to claim 2 or 3, characterized in that: The reaction conditions of the cracking reaction include: reaction temperature of 520-720°C, preferably 550-700°C; reaction time of 1-10s, preferably 1.5-6s; catalyst-oil ratio of (1-100):1, preferably (10-50):1; The reaction conditions of the lightening reaction include: reaction temperature of 530-730° C., preferably 560-680° C.; catalyst-oil ratio of (1-100):1, preferably (5-30):1; catalyst activity of 60-90.

5. The method according to any one of claims 2 to 4, characterized in that: The cracking catalyst and the lightening catalyst are the same or different; The cracking catalyst and the lightening catalyst each independently comprise a zeolite, an inorganic oxide and optionally clay; Preferably, based on the total weight of the cracking catalyst or the lightening catalyst, the content of the zeolite is 5-70% by weight, preferably 30-60% by weight; the content of the inorganic oxide is 1-95% by weight, preferably 30-70% by weight; the content of the clay is 1-50% by weight, preferably 5-40% by weight.

6. The method according to claim 5, characterized in that The zeolite of the cracking catalyst comprises large-pore zeolite and optional medium-pore zeolite; preferably, based on the total weight of the zeolite in the cracking catalyst, the content of large-pore zeolite is 30-99% by weight, preferably 40-80% by weight, and the content of medium-pore zeolite is 1-70% by weight, preferably 20-60% by weight; The zeolite of the light-weight catalyst includes large-pore zeolite and medium-pore zeolite; preferably, based on the total weight of the zeolite in the light-weight catalyst, the content of large-pore zeolite is 50-99% by weight, preferably 60-80% by weight, and the content of medium-pore zeolite is 1-50% by weight, preferably 20-40% by weight.

7. The method according to claim 6, characterized in that The medium-pore zeolite is ZSM zeolite; the large-pore zeolite is selected from one or more of β zeolite and Y zeolite; The inorganic oxide includes silicon dioxide and / or aluminum oxide; The clay is kaolin and / or halloysite.

8. The method according to any one of claims 2 to 7, characterized in that: The cracking catalyst and the lightening catalyst contain rare earth elements respectively. Preferably, the large-pore zeolite is β-zeolite or Y-type zeolite modified by rare earth elements.

9. The method according to any one of claims 1 to 8, characterized in that The first reactor is a riser reactor, a fluidized bed reactor or a combination of the two.

10. The method according to any one of claims 1 to 9, characterized in that The first reactor and the light-weight reactor are arranged in parallel or in series; When the first reactor and the lightening reactor are arranged in series, the first reactor The device is arranged downstream of the lightening reactor.

11. The method according to any one of claims 1 to 10, characterized in that The cracking reaction unit also includes a regenerator; The method further comprises: separating the catalyst to be regenerated and the cracking reaction product after the reaction in the first reactor; allowing the catalyst to be regenerated to enter the regenerator for regeneration to obtain a regenerated catalyst; returning the regenerated catalyst to the first reactor, preferably through a first regeneration inclined tube, and / or returning the regenerated catalyst to the lightening reactor, preferably through a second regeneration inclined tube; or, Separating the raw cracking catalyst and the cracking reaction product after the reaction in the first reactor; Separating the produced lightening catalyst and the lightening reaction product after the reaction in the lightening reactor; The regenerated cracking catalyst and the regenerated light-weighted catalyst are respectively entered into a common or separate regenerator for regeneration treatment to obtain a regenerated cracking catalyst and a regenerated light-weighted catalyst; the regenerated cracking catalyst is returned to the first reactor, preferably through a third regeneration inclined tube to the first reactor, and the regenerated light-weighted catalyst is returned to the light-weighted reactor, preferably through a fourth regeneration inclined tube to the light-weighted reactor.

12. The method according to claim 11, characterized in that Adding fresh agent to the lightening reaction, in: A fresh agent inlet is provided on the second regeneration inclined tube and / or at the bottom of the lightening reactor; or, A fresh agent inlet is provided on the fourth regeneration inclined tube and / or at the bottom of the lightening reactor. or, The regenerator is provided with an overflow bucket, and a fresh agent inlet is provided in the regenerator overflow bucket.

13. The method according to any one of claims 2 to 12, characterized in that: The product separation process comprises: The cracking reaction product and / or the lightening reaction product is subjected to a first separation to obtain the light gasoline, heavy gasoline and the other products; and the heavy gasoline is subjected to a second separation to obtain the gasoline middle fraction and the gasoline heavy fraction.

14. The method according to claim 13, characterized in that The initial boiling point of the light gasoline is 20-40°C; the distillation cut point between the light gasoline and the heavy gasoline is 80-100°C; the distillation cut point between the gasoline middle fraction and the gasoline heavy fraction is 120-150°C.

15. The method according to any one of claims 1 to 14, characterized in that: The bed density of the dense phase fluidized bed reactor is 300-500 kg / m 3 , the bed linear velocity is 0.1-3m / s, preferably 0.4-2m / s.

16. The method according to any one of claims 2 to 15, characterized in that: The light gasoline is returned to the cracking reaction unit to undergo the cracking reaction.

17. The method according to claim 1, characterized in that The method further comprises adding a fresh agent into the lightening reactor; The ratio of the amount of fresh agent added to the amount of catalyst circulation in the cracking reaction unit is less than 0.2.

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