CN111073684B

CN111073684B - Process for producing clean gasoline

Info

Publication number: CN111073684B
Application number: CN201811211803.6A
Authority: CN
Inventors: 尹晓莹; 赵乐平; 房莹; 尤百玲; 郭振东
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2018-10-18
Filing date: 2018-10-18
Publication date: 2021-08-31
Anticipated expiration: 2038-10-18
Also published as: CN111073684A

Abstract

The invention discloses a process method for producing clean gasoline. The method takes rich gas and crude gasoline from the top of a fractionating tower of a catalytic cracking unit as reaction raw materials, adopts a fluidized reactor, and specifically comprises the following steps: the reaction raw materials are sent into a fluidized reactor and are subjected to desulfurization and aromatization reaction with a mixed catalyst which is graded with an adsorption desulfurization catalyst and an aromatization catalyst under the condition of hydrogen to obtain a clean gasoline product. The method can save an absorption-stabilization system in the conventional catalytic cracking device, can produce clean gasoline with low sulfur and low olefin, and improves the yield and octane number of the gasoline.

Description

Process for producing clean gasoline

Technical Field

The invention relates to a process method for producing clean gasoline, in particular to a method for producing low-sulfur low-olefin clean gasoline.

Background

With the high-speed increase of Chinese economy, the keeping quantity of automobiles is continuously increased, and the keeping quantity of household automobiles reaches 2.05 hundred million by 6 months of 2017, which also causes the gasoline demand in China to show a continuously increasing state in recent years. Meanwhile, in order to reduce the discharge of harmful substances in the automobile exhaust, China sets increasingly strict clean gasoline standards. From 2017, the national V standard of sulfur-free gasoline (GB 17930-2016) is comprehensively implemented in China, the sulfur content is required to be no more than 10 mu g/g, the olefin content is no more than 24.0V%, and the aromatic hydrocarbon content is no more than 40V%. From 2019, the national VI clean gasoline standard implemented in stages in China is divided into A, B two stages, the national VIA standard requires that the sulfur content is no more than 10 mu g/g, the olefin content is no more than 18.0v%, the aromatic hydrocarbon content is no more than 35v%, and the olefin content in the national VIB standard is further limited to be less than 15 v%. The requirements of Chinese gasoline standards on the contents of sulfur, particularly olefin and aromatic hydrocarbon in gasoline are increasingly severe. Therefore, how to increase the yield of gasoline components and produce finished gasoline meeting national clean gasoline standards of V and VI is a difficult problem to be solved urgently by oil refining enterprises.

China is a catalytic cracking big country, more than 150 sets of catalytic cracking devices of different types are built and put into production, and the total processing capacity of the catalytic cracking devices reaches nearly 150 Mt/a. The catalytic cracking process generally consists of three parts, namely a reaction-regeneration system, a fractionation system and an absorption-stabilization system. The so-called absorption-stabilization system aims at separating the overhead gas (C) from the fractionation section₁~C₄Hydrocarbons) and a small amount of C₃、C₄The crude gasoline of the components is analyzed and separated to obtain dry gas, liquefied gas and catalytic cracking stable gasoline with qualified vapor pressure. In the product produced by the catalytic cracking device, the gas accounts for 10-20%, the gasoline component accounts for 40-60%, the diesel oil accounts for 20-40%, and the coke accounts for 5-10%. Liquefied gas component (C) in gas product of catalytic cracking unit₃、C₄Hydrocarbons) about 90% of the total mass of the gas, the balance being dry gas (C)₁、C₂Hydrocarbons). At present, most refineries sell dry gas and liquefied gas directly as fuels, the economic benefit is low, and C in the tower top gas is generally used in refineries with MTBE units₄The hydrocarbons are separated as feedstock for the production of MTBE. China will realize the popularization and use of ethanol gasoline in 2020, and the promotion is to use E10 vehicle ethanol gasoline without adding MTBE, and after the development of MTBE is hindered, the production raw material C is₄The export of hydrocarbons is a problem that oil refineries need to solve.

The gasoline component produced by the catalytic cracking unit accounts for about 70 percent of the total amount of the gasoline finished product. The sulfur content of the catalytic cracking gasoline is generally 200-1000 mug/g, and the olefin content is generally 20.0v% -45.0 v%. The sulfur and olefin contents in the catalytically cracked gasoline are high, and the reduction of the sulfur and olefin contents in the catalytically cracked gasoline is the key to meeting the increasingly strict clean gasoline standard.

In the existing catalytic cracking gasoline desulfurization technology, France Prime-G is mainly used⁺Selective hydrodesulfurization process and chinese petrochemical S zorb adsorption desulfurization process are representative. Prime-G⁺The selective hydrodesulfurization process adopts full-fraction pre-hydrogenation, light and heavy gasoline fractionation and selective hydrodesulfurization of heavy fraction gasoline, and the process produces sulfur with content not more than 10 mu g/gWhen the gasoline is cleaned, the octane number loss is large, and when the national VI standard gasoline with olefin not more than 15v% is produced, the octane number loss of the product is further increased due to hydrogenation saturation of the olefin. The S zorb adsorption desulfurization process adopts an adsorption desulfurization method to treat the full-range catalytic cracking gasoline. Compared with the raw material, the product has the advantages of greatly reduced sulfur content, basically unchanged density, distillation range and other properties, slightly reduced olefin, slightly increased alkane and (RON + MON)/2 loss of less than 1.0 unit. However, the method can not greatly reduce the olefin content in the gasoline product, and the problem of olefin reduction can not be solved for the catalytic cracking gasoline with higher olefin content.

CN107974279A discloses a gasoline treatment method. The method comprises the step of feeding a gasoline raw material into a fluidized reactor to perform desulfurization and aromatization reactions with a mixed catalyst of an adsorption desulfurization catalyst and an aromatization catalyst to obtain a desulfurization and aromatization gasoline product. The raw materials treated by the method are gasoline components such as catalytic cracking gasoline, catalytic cracking gasoline and the like, the octane number loss of the obtained gasoline product is small, but the contents of sulfur and olefin cannot meet the national VI clean gasoline standard that the sulfur content is not more than 10 mu g/g and the olefin content is not more than 15.0v%, and the octane number loss is increased if the removal rate of sulfur and olefin is increased.

CN104673377B discloses a method for upgrading catalytically cracked gasoline. The method comprises the steps of cutting a gasoline raw material into light, medium and heavy gasoline fractions, respectively treating the light fraction gasoline, performing sweetening treatment on the light fraction gasoline, performing adsorption desulfurization on the medium fraction gasoline, performing aromatization/isomerization reaction on the medium fraction gasoline, performing selective hydrodesulfurization reaction on the heavy fraction gasoline, and mixing the reaction products to obtain the modified gasoline. The raw material treated by the method is catalytic cracking gasoline, although the sulfur content and the olefin content in the product can be effectively reduced, the method has excessively complex process flow and higher energy consumption.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a process method for producing clean gasoline. The method can save an absorption-stabilization system in a conventional catalytic cracking device, can produce clean gasoline with low sulfur and low olefin, and improves the yield and octane number of the gasoline.

The invention provides a process method for producing clean gasoline, which takes rich gas and crude gasoline from the top of a fractionating tower of a catalytic cracking unit as reaction raw materials and adopts a fluidized reactor, and the process method comprises the following steps: the reaction raw materials are sent into a fluidized reactor and are subjected to desulfurization and aromatization reaction with a mixed catalyst which is graded with an adsorption desulfurization catalyst and an aromatization catalyst under the condition of hydrogen to obtain a clean gasoline product.

In the reaction raw material, the rich gas from the top of the fractionating tower of the catalytic cracking unit is generally C₁~C₄Hydrocarbons, naphtha, typically C₃~C₁₂The hydrocarbons may be from the top of the fractionating tower of the same catalytic cracking unit, or may be from the top of the fractionating tower of a different catalytic cracking unit.

Among said rich gases, the liquefied gas component (i.e. C)₃~C₄Hydrocarbons) in a proportion of 80 to 90v%, preferably 85 to 90v%, of the total amount of the rich gas. In the rich gas, the sulfur content is not more than 200 mug/g, preferably 20 mug/g-180 mug/g.

In the crude gasoline, the volume content of olefin is not less than 20v%, preferably 20v% to 45v%, the volume content of aromatic hydrocarbon is not more than 30v%, preferably 15v% to 25v%, and the mass content of sulfur is not more than 500 mu g/g, preferably 100 mu g/g to 500 mu g/g.

The mass ratio of rich gas to crude gasoline in the reaction raw materials is 1: 6-1: 2, preferably 1: 4-1: 3.

the fluidized reactor is a riser reactor or a fluidized bed reactor.

The fluidized bed reactor can be one or more selected from a fixed fluidized bed, a bulk fluidized bed, a bubbling bed, a turbulent bed, a fast bed, a conveying bed and a dense-phase fluidized bed; the riser reactor can be one or more selected from the group consisting of an equal-diameter riser, an equal-linear-speed riser and various variable-diameter risers.

When a fluidized reactor is adopted, a catalyst recycling process of grading an adsorption desulfurization catalyst and an aromatization catalyst is preferably adopted, and the method comprises the following specific steps:

firstly, in a reaction zone, carrying out desulfurization and aromatization reaction on reaction raw materials, an adsorption desulfurization catalyst and an aromatization catalyst;

secondly, separating a reaction product from the reacted catalyst;

thirdly, the catalyst after reaction is subjected to carbon burning activation in an oxidation regenerator;

fourthly, reducing and regenerating the activated catalyst by using hydrogen;

and fifthly, returning the regenerated catalyst to the desulfurization and aromatization reaction zone for next circulation.

Wherein, the condition for the carbon burning activation in the regenerator in the step three is as follows: the pressure is 0.5MPa to 1.5MPa, the volume ratio of the air agent is 500:1 to 1000:1, the temperature is kept constant at 400 ℃ to 550 ℃ for 3.0 to 10.0 hours, and the activated air is air.

In the mixed catalyst of the adsorption desulfurization catalyst and the aromatization catalyst grading, the weight content of the aromatization catalyst is 30.0wt% -60.0 wt%, preferably 40.0wt% -50.0 wt%.

The adsorption desulfurization catalyst can be a commercial adsorption desulfurization catalyst, and can also be prepared according to the prior art. The adsorption desulfurization catalyst can adopt a carrier containing alumina and zinc oxide, the carrier can also contain one or more of silica and bentonite, the loaded metal is one or more of VIB group and VIII group metals, preferably nickel, based on the weight of the adsorption desulfurization catalyst, the content of the carrier is 50.0-95.0 wt%, the content of the VIB group and/or VIII group metals calculated by elements is 5.0-50.0 wt%, wherein based on the weight of the adsorption desulfurization catalyst, the content of the zinc oxide is 15.0-80.0 wt%, and the content of the alumina is 10.0-35.0 wt%.

The aromatization catalyst comprises the following specific components: the catalyst comprises a ZSM-5/ZSM-22 composite molecular sieve, an active metal component and a binder.

Based on the weight of the catalyst, the content of the ZSM-5/ZSM-22 composite molecular sieve is 60.0wt% -80 wt%, preferably 65.0wt% -75.0 wt%, the content of the active metal oxide is 2.5wt% -5.0 wt%, preferably 3.0wt% -5.0 wt%, and the content of the binder is 15.0wt% -35.0 wt%, preferably 20.0wt% -30.0 wt%; wherein, in the ZSM-5/ZSM-22 composite molecular sieve, the weight content of the ZSM-5 molecular sieve is 30wt% -75 wt%, preferably 40wt% -70 wt%.

The aromatization catalyst preferably also can comprise an auxiliary agent, the auxiliary agent is preferably P, and the content of the auxiliary agent P is 0.5wt% -2.5 wt%, preferably 1.0wt% -2.0 wt% based on the weight of the catalyst.

The precursor of the aromatization catalyst and the auxiliary agent P can be one or a mixture of more of phosphoric acid, ammonium phosphate, ammonium metaphosphate, ammonium hydrogen phosphate and ammonium dihydrogen phosphate.

The aromatization catalyst comprises the active metal component which is the combination of at least one metal element in IIIB group and at least one metal element in VIII group, wherein the IIIB group metal is preferably La, and the VIII group metal element is preferably one or more of Ni and Co. Based on the weight of the catalyst, the content of the IIIB group metal in terms of oxide is 0.5wt% -2.0 wt%, and the content of the VIII group metal in terms of oxide is 0.5wt% -4.5 wt%.

In the aromatization catalyst, the binder is a binder used in the preparation process of the conventional catalyst, and one or more of alumina and silica are generally used.

In the ZSM-5/ZSM-22 composite molecular sieve, the ZSM-5 molecular sieve is preferably a zinc isomorphous substituted nano ZSM-5 molecular sieve, the molar ratio of silicon oxide to aluminum oxide is 50-200, preferably 100-200, and the particle size is 10-100 nm. Zinc in the isomorphously substituted zinc nano ZSM-5 molecular sieve is introduced into a molecular sieve framework structure in the preparation process of the molecular sieve and is synthesized by a hydrothermal method. In the zinc isomorphously substituted nano ZSM-5 molecular sieve, zinc accounts for 0.5wt% -4.0 wt%, preferably 1.0wt% -3.8 wt% of the weight of the zinc isomorphously substituted nano ZSM-5 molecular sieve calculated by elements.

In the ZSM-5/ZSM-22 composite molecular sieve, the ZSM-22 molecular sieve is preferably a microporous-mesoporous ZSM-22 molecular sieve, and the molar ratio of silica to alumina is 30-180, preferably 60-150. In the ZSM-5/ZSM-22 composite molecular sieve, the most probable pore diameter of mesopores is 3.5-10 nm, and the pore volume of the mesopores accounts for 30-75%, preferably 40-65% of the total pore volume.

The aromatization catalyst used in the process of the present invention may be prepared by the following method:

(1) preparing a ZSM-5/ZSM-22 composite molecular sieve;

(2) loading the active metal component on a ZSM-5/ZSM-22 composite molecular sieve, drying and roasting;

(3) and (3) mixing the molecular sieve obtained in the step (2) with a binder, and molding to obtain the aromatization catalyst.

Wherein, the auxiliary agent P is loaded at the same time of loading the active metal component in the step (2).

The preferred preparation method of the ZSM-5/ZSM-22 composite molecular sieve in the step (1) is as follows:

dispersing the zinc isomorphously substituted nano ZSM-5 molecular sieve in a synthesis system of the ZSM-22 molecular sieve, performing crystallization reaction for 24-72 hours at 140-180 ℃, washing, filtering and drying a product, and roasting for 3-12 hours at 400-600 ℃ to obtain the ZSM-5/ZSM-22 composite molecular sieve.

In the preparation method of the ZSM-5/ZSM-22 composite molecular sieve in the step (1), the synthesis system of the ZSM-22 molecular sieve is preferably as follows:

and uniformly mixing the reaction raw materials of a silicon source, an aluminum source, a template agent, a pore-expanding agent and water in proportion to obtain a ZSM-22 synthesis system. The pore-enlarging agent is preferably starch. Silicon source of SiO₂The aluminum source is A1₂O₃Calculated as C for starch₆H₁₀O₅The molar ratio of each component in the synthesis system is calculated as follows: SiO 2₂：A1₂O₃: template agent: starch: water = 1: 0.005-0.03: 0.1-0.6: 0.05-0.2: 20-60.

The silicon source is one or a mixture of tetraethyl orthosilicate, silica sol and water glass; the aluminum source is one or a mixture of more than two of pseudo-boehmite, aluminum sulfate, aluminum chloride and aluminum isopropoxide; the template agent is one or a mixture of more than two of 1, 6-hexamethylene diamine, 1-ethyl pyridine bromide and N-methyl imidazole biquaternary ammonium salt.

Loading the active metal component on the ZSM-5/ZSM-22 composite molecular sieve in the step (2) can be carried out by adopting a conventional impregnation method, such as an excess impregnation method, a saturated impregnation method, a spraying method and the like; or solid oxide and/or its precursor-metal salt or its hydroxide is mechanically mixed with molecular sieve, or precipitation method, sol treatment method, gelation method, etc., preferably impregnation method. Then drying and roasting are carried out to obtain the ZSM-5/ZSM-22 composite molecular sieve loaded with the active metal component. The drying is carried out for 3 to 15 hours at the temperature of 100 to 150 ℃, and the roasting is carried out for 3 to 10 hours at the temperature of 400 to 600 ℃.

The method for loading the auxiliary agent P in the step (2) is to carry out conventional impregnation on one or a mixture of more of P-containing precursor phosphoric acid, ammonium phosphate, ammonium metaphosphate, ammonium hydrogen phosphate and ammonium dihydrogen phosphate and the active metal component.

The molding in the step (3) is preferably performed by adopting a spray drying mode, and the particle size of the molded catalyst is 20-100 mu m. The temperature of the spray drying is 100-200 ℃.

In the method of the invention, the reaction conditions adopted are as follows: the reaction pressure is 1.0MPa to 4.5MPa, the reaction temperature is 300 ℃ to 500 ℃, and the liquid hourly volume space velocity is 1.0 h^-1~5.0h^-1The volume ratio of hydrogen to oil is 50: 1-250: 1; preferred reaction conditions are as follows: the reaction pressure is 1.5MPa to 3.0MPa, the reaction temperature is 320 ℃ to 400 ℃, and the liquid hourly volume space velocity is 2.0 h^-1~4.0h^-1The volume ratio of hydrogen to oil is 50: 1-150: 1.

In the method, the sulfur content in the clean gasoline is not more than 10 mu g/g, and the olefin content is not more than 15.0 v%.

In the method, the yield of the clean gasoline relative to the crude gasoline is more than 104%, preferably 110-116%, and the RON (research octane number) is increased by 0-0.9 unit, preferably 0.3-0.7 unit relative to the crude gasoline.

Compared with the prior art, the invention has the following advantages:

1. the method of the invention directly uses the tower top rich gas and the crude gasoline of the catalytic cracking device as reaction raw materials, carries out desulfurization and aromatization reaction with the mixed catalyst which is graded by the adsorption desulfurization catalyst and the aromatization catalyst, reduces the sulfur content in the gasoline, simultaneously carries out a plurality of reactions such as aromatization on of olefin in the raw materials, effectively reduces the olefin content in the gasoline, improves the octane number of the gasoline, simultaneously improves the yield of the gasoline, and can produce the clean gasoline with low sulfur and low olefin, particularly the sulfur content of not more than 10 mu g/g and the olefin content of not more than 15.0 v%.

2. The invention preferably uses the micropore-mesopore ZSM-22 molecular sieve and the zinc isomorphously substituted nanometer ZSM-5 molecular sieve to compound to obtain the ZSM-5/ZSM-22 composite molecular sieve, and the catalyst prepared by the composite molecular sieve is more suitable for improving the octane number of clean gasoline and reducing the olefin content; in addition, in the preparation method of the catalyst, the zinc isomorphous substituted nanometer ZSM-5 molecular sieve is dispersed in a synthesis system of the ZSM-22 molecular sieve, and the composite molecular sieve obtained by the specific preparation method is more beneficial to producing clean gasoline.

3. The method directly uses rich gas and crude gasoline at the top of the fractionating tower in the catalytic cracking device as reaction raw materials, saves an absorption-stabilization system in the catalytic cracking device, reduces the process flow, reduces the energy consumption and improves the economic benefit.

4. The method effectively utilizes the low-added-value rich gas yield-increasing high-added-value clean gasoline component in the catalytic cracking device, has high gasoline component yield, and obviously improves the economic benefit. Meanwhile, the problem of the outlet of the carbon-four hydrocarbon raw material in the catalytic cracking liquefied gas caused by the hindered development of MTBE due to the popularization of the ethanol gasoline can be solved.

5. The method combines the characteristics of rich gas and crude gasoline, preferably adopts a mixed catalyst of an adsorption desulfurization catalyst and a specific aromatization catalyst gradation, further promotes the olefin in the reaction raw material to generate a plurality of reactions such as proper aromatization and the like while desulfurizing the gasoline, so that the gasoline has higher octane number while having low content of aromatic hydrocarbon and olefin, reduces the cracking of gasoline components, promotes the conversion of the olefin in the rich gas, and improves the gasoline yield.

Drawings

FIG. 1 is a schematic flow diagram of the process of the present invention, wherein:

a-fluidized reactor, B-high pressure gas-liquid separator, C-hydrogen sulfide removal unit treatment, D-stripping tower, 1-rich gas, 2-crude gasoline, 3-new hydrogen, 4-desulfurization and aromatization product, 5-gas, 6-light hydrocarbon containing gasoline, 7-circulating hydrogen, 8-liquefied gas and 9-clean gasoline product.

Figure 2 is an XRD diffractogram of different molecular sieves, wherein:

a-ZSM-5 in example 3, b-ZSM-22 in example 3, c-ZSM-5/ZSM-22 composite molecular sieve CM-1 in example 1, d-ZSM-5, ZSM-22 mixed molecular sieve in example 3.

FIG. 3 is a mesoporous distribution diagram of the ZSM-5/ZSM-22 composite molecular sieve CM-1 synthesized in example 1 of the present invention.

Detailed Description

The method and effect of the present invention will be further described with reference to the accompanying drawings and examples, but the present invention is not limited thereto.

The process of the present invention is described in detail below with reference to FIG. 1.

Mixing tower top rich gas 1, crude gasoline 2 and hydrogen (new hydrogen 3+ recycle hydrogen 7) from a fractionating tower of a catalytic cracking unit, and then carrying out desulfurization and aromatization reaction in a fluidized reactor A to generate a desulfurization and aromatization product 4; the desulfurization and aromatization product 4 enters a high-pressure gas-liquid separator B, gas 5 is separated from the top, and light hydrocarbon-containing gasoline 6 is separated from the bottom; the gas 5 is treated by a hydrogen sulfide removal unit C and then enters a fluidization reactor A as circulating hydrogen 7 together with new hydrogen 3; and (3) passing the light hydrocarbon-containing gasoline 6 through a stripping tower D, separating liquefied gas 8 at the tower top, and obtaining a low-sulfur low-olefin clean gasoline product 9 at the tower bottom.

The present invention will be described in detail with reference to examples.

The properties of the catalytic cracking overhead gas-rich feedstock and the naphtha feedstock used in the examples and comparative examples are shown in tables 1 and 2.

In the invention, XRD analysis adopts a Japanese physical D/max2500 type X-ray diffractometer, a Cu target, a Ka radiation source, a graphite monochromator, a voltage of 40kV, a current of 80mA, a step length of 0.1 ︒ and a scanning speed of 1 ︒/min. The pore volume and pore size distribution of the molecular sieve are measured by adopting a American Mike ASAP2400 type physical adsorption instrument and adopting a low-temperature liquid nitrogen adsorption method.

Example 1

The aromatization catalyst OTA-F-1 of this example was recoveredZSM-5/ZSM-22 composite molecular sieve CM-1 is used, and in the ZSM-5/ZSM-22 composite molecular sieve CM-1, zinc isomorphously replaces nano ZSM-5 molecular Sieve (SiO)₂/Al₂O₃The mol ratio is 120, the Zn content is 3.5wt%, the grain diameter is 80 nm) accounts for 60wt% of the total weight of the composite molecular sieve, and the ZSM-22 molecular Sieve (SiO) with a micropore-mesopore structure₂/Al₂O₃The molar ratio is 90) accounts for 40wt% of the total weight of the composite molecular sieve. In the ZSM-5/ZSM-22 composite molecular sieve CM-1, the most probable pore diameter of mesopores is 4.5nm, and the pore volume of the mesopores accounts for 60 percent of the total pore volume.

The composition of the aromatization catalyst OTA-F-1 is as follows: the content of the ZSM-5/ZSM-22 composite molecular sieve CM-1 is 70.0wt percent, the content of P is 1.5wt percent, and the content of La is₂O₃1.5wt%, NiO 3.5wt%, and alumina as adhesive.

The preparation method of the OTA-F-1 catalyst comprises the following steps:

0.8g of pseudo-boehmite, 100g of silica sol (30 wt% of silicon dioxide aqueous solution), 11.6g of 1, 6-hexanediamine, 8.1g of starch and 110g of deionized water are stirred and mixed for 1 hour to form uniform precursor solution. Uniformly dispersing 45.8g of zinc isomorphously substituted nano ZSM-5 molecular sieve into the precursor solution, stirring for 30min to form a uniform mixed solution, transferring the mixed solution into a reaction kettle with a polytetrafluoroethylene lining for sealing, statically crystallizing for 48h at 150 ℃, washing, filtering and drying to obtain solid powder, and roasting for 8h at 550 ℃ to obtain CM-1. As can be seen from XRD diffraction analysis (see figure 2) of CM-1, CM-1 has typical diffraction peaks of ZSM-5 and ZSM-22, and is basically free of heterocrystal, and is a ZSM-5/ZSM-22 composite molecular sieve. The analysis of the low-temperature liquid nitrogen adsorption method shows that the CM-1 has a micropore-mesopore structure, wherein the mesopore diameter distribution is shown in figure 3.

Putting ZSM-5/ZSM-22 composite molecular sieve CM-1 into a spray-leaching tank, spraying a solution containing phosphoric acid, lanthanum nitrate and nickel nitrate onto the composite molecular sieve CM-1 within 30 minutes, drying at room temperature, drying for 10 hours at 120 ℃, and roasting at 500 ℃ for 8 hours to obtain an active metal loaded molecular sieve; adding the molecular sieve loaded with active metal into the alumina sol, and spray drying at 120 ℃ to prepare the microspheric aromatization catalyst OTA-F-1.

Example 2

The ZSM-5/ZSM-22 composite molecular sieve CM-1 used in the aromatization catalyst OTA-F-2 in this example was the same as in example 1.

The composition of the catalyst OTA-F-2 is as follows: the content of the ZSM-5/ZSM-22 composite molecular sieve CM-1 is 75.0wt percent, the content of P is 2.0wt percent, and the content of La is₂O₃The content was 1.0wt%, the CoO content was 4.0wt%, and the balance was binder alumina.

The preparation method of the OTA-F-2 catalyst comprises the following steps:

putting ZSM-5/ZSM-22 composite molecular sieve CM-1 into a spray-leaching tank, spraying ammonium hydrogen phosphate, lanthanum nitrate and cobalt nitrate solution onto the composite molecular sieve within 30 minutes, drying at room temperature, drying for 10 hours at 120 ℃, and roasting at 500 ℃ for 8 hours to obtain the active metal loaded molecular sieve; adding the molecular sieve loaded with active metal into the alumina sol, and spray drying at 120 ℃ to prepare the microspheric catalyst OTA-F-2.

Example 3

This example differs from example 1 in that a ZSM-5, ZSM-22 mixed molecular sieve was used, and the product obtained in example 1 was identified as ZSM-22 molecular sieve by XRD diffraction analysis (see FIG. 2) without adding ZSM-5 molecular sieve in the preparation of CM-1. The ZSM-5 and ZSM-22 mixed molecular sieve has a micropore-mesopore structure through the analysis of a low-temperature liquid nitrogen adsorption method. The aromatization catalyst OTA-F-3 of this example had the following composition: the zinc isomorphously substituted nano ZSM-5 molecular sieve (same as example 1) content was 42wt%, ZSM-22 molecular Sieve (SiO)₂/Al₂O₃Molar ratio of 90) 28wt%, P1.5 wt%, La₂O₃1.5wt%, NiO 3.5wt%, and alumina as adhesive.

The preparation method of the OTA-F-3 catalyst comprises the following steps:

uniformly mixing a zinc isomorphously substituted nano ZSM-5 molecular sieve and a ZSM-22 molecular sieve, putting the mixture into a spray-leaching tank, spraying a solution containing phosphoric acid, lanthanum nitrate and nickel nitrate onto a composite molecular sieve within 30 minutes, drying the composite molecular sieve at room temperature, drying the composite molecular sieve for 10 hours at 120 ℃, and roasting the composite molecular sieve for 8 hours at 500 ℃ to obtain an active metal-loaded molecular sieve; adding the molecular sieve loaded with active metal into the alumina sol, and spray drying at 120 ℃ to prepare the microspheric aromatization catalyst OTA-F-3.

Example 4

Compared with example 1, ZSM-5/ZSM-22 composite molecular sieve CM-2 is adopted for preparing the catalyst OTA-F-4 in the example. The difference between the ZSM-5/ZSM-22 composite molecular sieve CM-2 and the CM-1 is that starch is not added in a ZSM-22 molecular sieve powder synthesis system to obtain the CM-2, the XRD diffraction analysis of the CM-2 can be known as the ZSM-5/ZSM-22 composite molecular sieve, the analysis of a low-temperature liquid nitrogen adsorption method shows that the CM-2 only has a micropore structure, and the rest is the same as the example 1 to obtain the OTA-F-4 with the aromatization catalyst.

Example 5

The reaction raw materials are rich gas at the top of the industrial catalytic cracking unit and crude gasoline, and the mass ratio of the rich gas at the top of the industrial catalytic cracking unit to the crude gasoline in the reaction raw materials is 1: 4, the properties of the raw materials are shown in tables 1 and 2. The adsorption desulfurization catalyst CF-1 is prepared by a conventional method, and comprises the following components by weight: 38wt% of zinc oxide, 21wt% of silicon oxide, 34wt% of aluminum oxide and 7wt% of nickel simple substance. The adsorption desulfurization catalyst CF-1 and the OTA-F-1 aromatization catalyst are graded and mixed, wherein the OTA-F-1 catalyst accounts for 40.0wt percent of the total weight of the graded and mixed catalyst. 40mL of mixed catalyst which is graded by the adsorption desulfurization catalyst CF-1 and the OTA-F-1 aromatization catalyst is filled into a small-sized continuous fluidized bed reactor, the reaction raw materials carry out desulfurization and aromatization reactions in a fluidized bed, and the reaction process conditions are as follows: the reaction pressure is 1.8MPa, the reaction temperature is 380 ℃, and the liquid hourly space velocity is 3.0h^-1The volume ratio of hydrogen to oil is 120: 1. The conditions for the charcoal-fired activation of the catalyst were as follows: the pressure is 1.4MPa, the volume ratio of the gas agent is 550:1, the temperature is kept for 10 hours at 480 ℃, the activated gas is air, the activated catalyst is reduced and regenerated by hydrogen, and the regenerated catalyst returns to the reactor for recycling. After 200h of operation, the properties of the gasoline product obtained are shown in Table 3.

Example 6

The difference compared to example 5 is that the aromatization catalyst used was OTA-F-2 and the properties of the resulting gasoline product are shown in Table 3.

Example 7

The difference compared to example 5 is that the aromatization catalyst used was OTA-F-3 and the properties of the resulting gasoline product are shown in Table 3.

Example 8

The difference compared to example 5 is that the aromatization catalyst used was OTA-F-4 and the properties of the resulting gasoline product are shown in Table 3.

Example 9

Compared with the example 5, the difference is that the mass ratio of the tower top rich gas to the crude gasoline in the reaction raw material is 1: 3.5 and the properties of the gasoline product obtained are shown in table 3.

Comparative example 1

Compared with example 5, the difference is that the catalyst used is only the adsorption desulfurization catalyst CF-1, the aromatization catalyst OTA-F-1 is not added, and the properties of the obtained gasoline product are shown in Table 4.

Comparative example 2

Compared with example 5, the difference is that the catalyst used is only commercial FCAS adsorption desulfurization catalyst, no aromatization catalyst OTA-F-1 is added, and the properties of the obtained gasoline product are shown in Table 4.

Comparative example 3

Compared with example 5, the difference is that the catalyst used is the commercialized FCAS adsorption desulfurization catalyst and OTAZ-C-3 aromatization catalyst used in example 1 in CN107974279A, wherein the properties of the gasoline product obtained by using 7% of the OTAZ-C-3 catalyst based on the total weight of the catalyst are shown in Table 4.

It can be seen from table 3 that in example 5, the yield of gasoline is improved by 13.9% compared with the raw gasoline, the octane number is improved by 0.5 unit, and both the sulfur and olefin contents in the product meet the clean gasoline standard with sulfur content no more than 10 μ g/g and olefin content no more than 15.0 v%. In example 6, the yield of gasoline is improved by 13.5% compared with raw gasoline raw material, the octane number is improved by 0.4 unit, and the sulfur and olefin contents in the product both meet the clean gasoline standard with sulfur content no more than 10 mu g/g and olefin content no more than 15.0 v%. In example 7, the yield of gasoline is increased by 5.6% compared with raw gasoline, the octane number is not reduced, and the sulfur and olefin contents in the product both meet the clean gasoline standard with sulfur content no more than 10 mu g/g and olefin content no more than 15.0 v%. In example 8, the yield of gasoline is increased by 5.4% compared with raw gasoline, the octane number is not reduced, and the sulfur and olefin contents in the product both meet the clean gasoline standard with sulfur content no more than 10 μ g/g and olefin content no more than 15.0 v%. In example 9, the yield of gasoline is increased by 16.7% compared with raw gasoline raw material, the octane number is increased by 0.6 unit, and the sulfur and olefin contents in the product both satisfy the clean gasoline standard with sulfur content no more than 10 μ g/g and olefin content no more than 15.0 v%.

As can be seen from Table 4, in comparative example 1, compared with the raw gasoline raw material, the yield of the gasoline is 97.5%, the gasoline component is not increased, the octane number is reduced by 0.6 unit, the sulfur content in the product is not more than 10 mu g/g, but the reduction amplitude of the olefin content is limited, and the olefin content is 19.5 v%. In comparative example 2, compared with raw gasoline raw material, the yield of gasoline is 97.4%, gasoline components are not increased, the octane number is reduced by 0.6 unit, the sulfur content in the product is not more than 10 mu g/g, but the reduction amplitude of the olefin content is limited, and the olefin content is 19.8 v%. In comparative example 3, compared with a raw gasoline raw material, the yield of the gasoline is 96.9%, gasoline components are not increased, the octane number is reduced by 0.3 unit, the sulfur content in the product is not more than 10 mu g/g, but the reduction amplitude of the olefin content is limited, and the olefin content is 20.6 v%.

TABLE 1 raw material overhead gas enrichment Properties

Composition of	By volume content of%
		Hydrogen gas	1.23
Methane	2.25
		Ethane (III)	2.3
Ethylene	4.32
		Propane	1.87
Propylene (PA)	25.73
		Isobutane	14.36
N-butane	10.38
		N-butene	4.75
Isobutene	10.85
		Butene of trans-butene	10.02
Cis-butenediol	11.57
		C5 and C5 or above components	0.36
Total of	100
		Sulphur, microgram/g	68

TABLE 2 raw gasoline Properties

Properties of	Raw gasoline feedstock
		Density, g/cm³	0.730
Sulphur, microgram/g	188
		RON	90.7
FIA process gasoline composition
		Alkane content, v%	49.1
Olefin content, v%	29.8
		Aromatic content, v%	21.1
Distillation range, deg.C
		Initial boiling point	26
10%	48
		50%	98
90%	176
		End point of distillation	198

TABLE 3 gasoline product Properties after reaction

Experimental protocol	Example 5	Example 6	Example 7	Example 8	Example 9
						Reaction raw material	Tower top rich gas and crude gasoline	Tower top rich gas and crude gasoline	Tower top rich gas and crude gasoline	Tower top rich gas and crude gasoline	Tower top rich gas and crude gasoline
Catalyst and process for preparing same	CF-1+ OTA-F-1	CF-1+ OTA-F-2	CF-1+ OTA-F-3	CF-1+ OTA-F-4	CF-1+ OTA-F-1
						Yield relative to raw crude gasoline as raw material%	113.9	113.5	105.6	105.4	116.7
Density, g/cm³	0.733	0.733	0.733	0.733	0.734
						Sulphur, microgram/g	6.5	6.5	6.8	6.8	6.5
RON	91.2	91.1	90.7	90.7	91.3
						FIA process gasoline composition
Alkane content, v%	56.7	57.0	58.3	58.3	56.3
						Olefin content, v%	12.5	12.9	14.2	14.6	12.3
Aromatic content, v%	30.8	30.1	27.5	27.1	31.4
						Distillation range, deg.C
Initial boiling point	36	36	35	36	36
						10%	52	51	51	51	52
50%	102	102	101	102	103
						90%	179	179	178	178	178
End point of distillation	200	200	199	199	200

TABLE 4 gasoline product Properties after reaction

Experimental protocol	Comparative example 1	Comparative example 2	Comparative example 3
				Reaction raw material	Tower top rich gas and crude gasoline	Tower top rich gas and crude gasoline	Tower top rich gas and crude gasoline
Catalyst and process for preparing same	CF-1	FCAS	FCAS+OTAZ-C-3
				Yield relative to raw crude gasoline as raw material%	97.5	97.4	97.1
Density, g/cm³	0.731	0.731	0.733
				Sulphur, microgram/g	6.5	7.0	7.2
RON	90.1	90.1	90.4
				FIA process gasoline composition
Alkane content, v%	59.3	59.1	54.9
				Olefin content, v%	19.5	19.8	20.6
Aromatic content, v%	21.2	21.1	24.5
				Distillation range, deg.C
Initial boiling point	36	36	36
				10%	48	48	50
50%	100	100	102
				90%	176	176	178
End point of distillation	198	198	200

It can be seen from the above that the invention can effectively reduce the sulfur and olefin content in the gasoline, improve the octane number of the gasoline, meet the increasingly severe standards for clean gasoline, and increase the yield of gasoline components.

Claims

1. A process for preparing clean gasoline from the rich gas and raw gasoline from the tower top of fractionating tower in catalytic cracker features that a fluidized reactor is used, and includes: feeding the reaction raw materials into a fluidized reactor, and carrying out desulfurization and aromatization reaction on the reaction raw materials and a mixed catalyst graded by an adsorption desulfurization catalyst and an aromatization catalyst under the hydrogen condition to obtain a clean gasoline product; wherein, the aromatization catalyst comprises a ZSM-5/ZSM-22 composite molecular sieve, an active metal component and a binder;

the reaction conditions were as follows: the reaction pressure is 1.0MPa to 4.5MPa, the reaction temperature is 300 ℃ to 500 ℃, and the liquid hourly volume space velocity is 1.0 h^-1~5.0h^-1The volume ratio of hydrogen to oil is 50: 1-250: 1;

the aromatization catalyst takes the weight of the catalyst as a reference, the content of the ZSM-5/ZSM-22 composite molecular sieve is 60.0wt% -80 wt%, the content of the active metal oxide is 2.5wt% -5.0 wt%, and the content of the binder is 15.0wt% -35.0 wt%; wherein in the ZSM-5/ZSM-22 composite molecular sieve, the weight content of the ZSM-5 molecular sieve is 30wt% -75 wt%; in the ZSM-5/ZSM-22 composite molecular sieve, the ZSM-5 molecular sieve is a zinc isomorphous substituted nano ZSM-5 molecular sieve, the molar ratio of silicon oxide to aluminum oxide is 50-200, and the particle size is 10-100 nm; in the zinc isomorphously substituted nano ZSM-5 molecular sieve, zinc accounts for 0.5 to 4.0 weight percent of the weight of the zinc isomorphously substituted nano ZSM-5 molecular sieve in terms of elements; in the ZSM-5/ZSM-22 composite molecular sieve, the ZSM-22 molecular sieve is a microporous-mesoporous ZSM-22 molecular sieve, and the molar ratio of silicon oxide to aluminum oxide is 30-180; in the ZSM-5/ZSM-22 composite molecular sieve, the most probable pore diameter of mesopores is 3.5-10 nm, and the pore volume of the mesopores accounts for 30-75% of the total pore volume.

2. A process according to claim 1, characterized in that: in the rich gas, the content of the liquefied gas component accounts for 80-90 v% of the total amount of the rich gas; the sulfur content is not more than 200 mu g/g.

3. A process according to claim 2, wherein: in the rich gas, the content of the liquefied gas component accounts for 85-90 v% of the total amount of the rich gas; the sulfur content is 20-180 mug/g.

4. A process according to claim 1, characterized in that: in the crude gasoline, the volume content of olefin is not less than 20v%, the volume content of aromatic hydrocarbon is not more than 30v%, and the mass content of sulfur is not more than 500 mu g/g.

5. The process according to claim 4, wherein: in the crude gasoline, the volume content of olefin is 20v% -45 v%, the volume content of aromatic hydrocarbon is 15v% -25 v%, and the mass content of sulfur is 100 mug/g-500 mug/g.

6. A process according to claim 1, characterized in that: the mass ratio of rich gas to crude gasoline in the reaction raw materials is 1: 6-1: 2.

7. the process according to claim 6, wherein: the mass ratio of rich gas to crude gasoline in the reaction raw materials is 1: 4-1: 3.

8. a process according to claim 1, characterized in that: the fluidized reactor is a riser reactor or a fluidized bed reactor.

9. A process according to claim 1, characterized in that: in the mixed catalyst of the adsorption desulfurization catalyst and the aromatization catalyst grading, the weight content of the aromatization catalyst is 30.0wt% -60.0 wt%.

10. A process according to claim 1, characterized in that: in the mixed catalyst of the adsorption desulfurization catalyst and the aromatization catalyst grading, the weight content of the aromatization catalyst is 40.0wt% -50.0 wt%.

11. A process according to claim 1, characterized in that: the aromatization catalyst also comprises an auxiliary agent, wherein the auxiliary agent is P, and the content of the auxiliary agent P is 1.0wt% -2.0 wt% based on the weight of the catalyst.

12. A process according to claim 11, wherein: the content of the additive P is 1.0-2.0 wt%.

13. A process according to claim 1, characterized in that: the aromatization catalyst takes the weight of the catalyst as a reference, the content of the ZSM-5/ZSM-22 composite molecular sieve is 65.0wt% -75.0 wt%, the content of the active metal oxide is 3.0wt% -5.0 wt%, and the content of the binder is 20.0wt% -30.0 wt%; wherein in the ZSM-5/ZSM-22 composite molecular sieve, the weight content of the ZSM-5 molecular sieve is 40wt% -70 wt%.

14. A process according to claim 1, characterized in that: the active metal component is a combination of at least one metal element in a IIIB group and at least one metal element in a VIII group, wherein the IIIB group metal is La, and the VIII group metal element is one or more of Ni and Co; based on the weight of the catalyst, the content of the IIIB group metal in terms of oxide is 0.5wt% -2.0 wt%, and the content of the VIII group metal in terms of oxide is 0.5wt% -4.5 wt%.

15. A process according to claim 1, characterized in that: the molar ratio of silicon oxide to aluminum oxide of the nano ZSM-5 molecular sieve is 100-200, and in the zinc isomorphously substituted nano ZSM-5 molecular sieve, zinc accounts for 1.0-3.8 wt% of the weight of the zinc isomorphously substituted nano ZSM-5 molecular sieve in terms of elements.

16. A process according to claim 1, characterized in that: the molar ratio of silicon oxide to aluminum oxide of the ZSM-22 molecular sieve is 60-150, and the mesoporous volume of the ZSM-5/ZSM-22 composite molecular sieve accounts for 340-65% of the total pore volume.

17. A process according to claim 1, characterized in that: the preparation method of the aromatization catalyst comprises the following steps:

(1) preparing a ZSM-5/ZSM-22 composite molecular sieve;

18. The process of claim 17 wherein: the preparation method of the ZSM-5/ZSM-22 composite molecular sieve in the step (1) comprises the following steps: dispersing the zinc isomorphously substituted nano ZSM-5 molecular sieve in a synthesis system of the ZSM-22 molecular sieve, performing crystallization reaction for 24-72 hours at 140-180 ℃, washing, filtering and drying a product, and roasting for 3-12 hours at 400-600 ℃ to obtain the ZSM-5/ZSM-22 composite molecular sieve.

19. A process according to claim 18, wherein: the synthesis system of the ZSM-22 molecular sieve is as follows: uniformly mixing reaction raw materials including a silicon source, an aluminum source, a template agent, a pore-expanding agent and water in proportion to obtain a ZSM-22 synthesis system; the pore-enlarging agent is starch; silicon source of SiO₂The aluminum source is A1₂O₃Calculated as C for starch₆H₁₀O₅The molar ratio of each component in the synthesis system is calculated, namely SiO₂：A1₂O₃: template agent: starch: water = 1: 0.005-0.03: 0.1-0.6: 0.05-0.2: 20-60.

20. A process according to claim 19, wherein: the silicon source is one or a mixture of tetraethyl orthosilicate, silica sol and water glass; the aluminum source is one or a mixture of more than two of pseudo-boehmite, aluminum sulfate, aluminum chloride and aluminum isopropoxide; the template agent is one or a mixture of more than two of 1, 6-hexamethylene diamine, 1-ethyl pyridine bromide and N-methyl imidazole biquaternary ammonium salt.

21. The process of claim 17 wherein: the drying in the step (2) is carried out for 3 to 15 hours at the temperature of 100 to 150 ℃, and the roasting is carried out for 3 to 10 hours at the temperature of 400 to 600 ℃.

22. The process of claim 17 wherein: the molding in the step (3) is performed by adopting a spray drying mode, the particle size of the molded catalyst is 20-100 mu m, and the temperature of spray drying is 100-200 ℃.

23. The process of claim 17 wherein: and (2) loading an auxiliary agent P while loading the active metal component.

24. A process according to claim 1, characterized in that: the reaction conditions were as follows: the reaction pressure is 1.5MPa to 3.0MPa, the reaction temperature is 320 ℃ to 400 ℃, and the liquid hourly volume space velocity is 2.0 h^-1~4.0h^-1The volume ratio of hydrogen to oil is 50: 1-150: 1.

25. A process according to claim 1, characterized in that: the sulfur content in the clean gasoline is not more than 10 mu g/g, and the olefin content is not more than 15.0 v%.

26. A process according to claim 1, characterized in that: the yield of the clean gasoline relative to the crude gasoline is more than 104%, and the RON is increased by 0-0.9 unit relative to the crude gasoline.

27. The process of claim 26 wherein: the yield of the clean gasoline relative to the crude gasoline is 110-116%, and the RON is increased by 0.3-0.7 unit relative to the crude gasoline.