CN105582997B - The method of catalyst of naphtha catalytic cracking production propylene and preparation method thereof and naphtha catalytic cracking production propylene - Google Patents

Abstract

The present invention provides a kind of catalyst of naphtha catalytic cracking production propylene and preparation method thereof, which includes ordered structure carrier and the active component coating for being distributed in ordered structure inner surface of the carrier and/or outer surface；The molecular sieve is the molecular sieve with ten-ring two-dimensional elliptic type pore passage structure.The present invention also provides a kind of methods of naphtha catalytic cracking production propylene.Using catalyst provided by the invention, the yield of propylene can be improved, and obtains propylene/ethylene more than 1.

Description

Catalyst for producing propylene by catalytic cracking of naphtha, preparation method thereof and naphtha catalysis The method of pyrolysis to produce propylene

technical field

The present invention relates to a catalyst for producing propylene by catalytic cracking of naphtha and a preparation method thereof and a method for producing propylene by catalytic cracking of naphtha, in particular to a catalyst for producing propylene by catalytic cracking of naphtha, a catalyst for preparing naphtha A method for cracking a catalyst for producing propylene and the prepared catalyst, and a method for producing propylene by catalytic cracking of naphtha.

Background technique

Propylene is one of the most widely used basic organic chemical raw materials, mainly used in the production of polypropylene, cumene, acrylonitrile, acrylic acid, etc. At present, propylene mainly comes from ethylene cracking units in petrochemical plants and catalytic cracking units in refineries. With the rapid growth of global demand for propylene, the output of traditional production processes is difficult to meet the demand, so the development of technology to increase the production of propylene has become an important development direction in petrochemical production technology.

Conventional ethylene cracking mainly uses naphtha as raw material to produce ethylene and propylene through steam thermal cracking. Limited by the thermal cracking reaction mechanism, ethylene is generally the main product and propylene is the by-product. The propylene/ethylene ratio is limited to about 0.65, which is higher than At this ratio, the total olefin yield will decrease. This process needs to consume a large amount of high-quality naphtha raw material, which is a process with high energy consumption. Currently 66-70% of propylene is produced by steam thermal cracking technology.

The reaction temperature of catalytic cracking is about 50-200°C lower than that of steam thermal cracking, and the energy consumption is lower. Moreover, the reaction mechanism of catalytic cracking is beneficial to the formation of propylene molecules, so that the yield of propylene produced from naphtha can be increased.

CN101491772A discloses a catalyst for catalytic cracking of naphtha, which comprises the following active components in weight percent: a) 80-99.5% is selected from the intergrowth molecular sieves of ZSM-5 and mordenite, ZSM-5 and zeolite beta At least one of the intergrown molecular sieves or the intergrown molecular sieves of ZSM-5 and Y zeolite; and b) the balance carried thereon is at least one element selected from Group VA elements of the Periodic Table of Elements or its oxides. But the diene yield of ethylene and propylene that can be obtained by this catalyst is still low.

CN102861604A discloses a catalyst for producing olefins by catalytic cracking of naphtha, wherein, based on the weight content of the final catalyst, it contains 60-90% EU-1/ZSM-5 composite molecular sieve and 0.5-3% heteropolyacid. When the catalyst is actually used for catalytic cracking of naphtha, although the yield of ethylene and propylene diene is high, the ratio of propylene/ethylene is still low, and the yield of propylene obtained is small.

It can be seen that, in order to achieve a larger yield of propylene by catalytic cracking of naphtha, a new catalyst for the production of propylene by catalytic cracking of naphtha is needed.

Contents of the invention

The purpose of the present invention is to overcome the problem of small propylene output in the prior art when catalytic cracking of naphtha is used to produce propylene, and to provide a catalyst for producing propylene by catalytic cracking of naphtha and a preparation method thereof and a method for producing propylene by catalytic cracking of naphtha .

In order to achieve the above object, the present invention provides a catalyst for producing propylene by catalytic cracking of naphtha, the catalyst includes a regular structure carrier and an active component coating distributed on the inner surface and/or outer surface of the regular structure carrier; Based on the total weight of the active component coating, the content of the active component coating is 10-50% by weight; based on the total weight of the active component coating, the active component coating contains 50-95% by weight Molecular sieve and 5-50% by weight of the matrix; the molecular sieve is a molecular sieve with a ten-membered ring two-dimensional elliptical pore structure.

The present invention also provides a method for preparing a catalyst for producing propylene by catalytic cracking of naphtha, the method comprising: (1) mixing and grinding a molecular sieve and an aqueous solvent to obtain a molecular sieve slurry, and the molecular sieve is a two-dimensional A molecular sieve with an elliptical pore structure; (2) mixing the molecular sieve slurry with the matrix source to form an active component coating slurry; (3) coating a structured carrier with the active component coating slurry and drying and Roasting.

The present invention also provides the catalyst prepared by the method provided by the present invention.

The present invention also provides a method for producing propylene by catalytic cracking of naphtha, the method comprising: under the reaction conditions of catalytic cracking of naphtha, contacting naphtha and water with a catalyst to obtain a propylene product, wherein the catalyst Catalyst provided by the present invention.

By adopting the catalyst provided by the invention, the yield of propylene can be increased, and the ratio of propylene/ethylene to 1 or more can be obtained. For example, in Example 1, using a catalyst with a regular structure support and an active component coating containing a molecular sieve with a ten-membered ring two-dimensional elliptical pore structure, in the product obtained by catalytic cracking of naphtha, C ₂ ⁼ -C ₄ ⁼ The selectivity of C 2 ⁼ +C 3 ⁼ is 90.8%, the yield of C ₂ =+C ₃ = is 68.23%, and the ratio of C ₃ ⁼ /C ₂ ⁼ is 1.7, which can realize more propylene production.

Other features and advantages of the present invention will be described in detail in the following detailed description.

Detailed ways

Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

In the present invention, the term regular structure catalyst is used to refer to a catalyst comprising a regular structure carrier and an active component coating distributed on the inner surface and/or outer surface of the carrier; the regular structure carrier is a carrier with a regular structure such as a honeycomb carrier; the regular structure The reactor is a fixed-bed reactor filled with a structured catalyst as a catalyst bed.

The invention provides a catalyst for producing propylene by catalytic cracking of naphtha, the catalyst comprises a regular structure carrier and an active component coating distributed on the inner surface and/or outer surface of the regular structure carrier; the total weight of the catalyst is Based on the basis, the content of the active component coating is 10-50% by weight; based on the total weight of the active component coating, the active component coating contains 50-95% by weight of molecular sieve and 5- 50% by weight of the matrix; the molecular sieve is a molecular sieve with a ten-membered ring two-dimensional elliptical pore structure.

The present invention has a molecular sieve with a ten-membered ring two-dimensional elliptical pore structure, preferably a kind of FER or MFS structure as a catalytic cracking active component, and the molecular sieve and matrix are made into an active component coating and distributed on a regular structure carrier, By forming a regular structure catalyst, a higher yield of propylene from catalytic cracking of naphtha can be obtained.

According to the present invention, the molecular sieve is a molecular sieve having a ten-membered ring two-dimensional elliptical pore structure, preferably with a pore opening diameter of 0.45-0.56 nanometers.

According to the present invention, preferably, the molecular sieve is a molecular sieve of FER structure and/or a molecular sieve of MFS structure. The structure types FER and MFS refer to the molecular sieve structure named by the International Zeolite Association (IZA), which is used to describe the spatial topology of the pores in the molecular sieve. The molecular sieves of the FER structure include ZSM-35 zeolite, Ferrierite zeolite, FU-9 zeolite, ISI-6 zeolite, NU-23 zeolite and Sr-D zeolite, etc., and the molecular sieves of the MFS structure include ZSM-57 zeolite and COK-5 zeolite Wait.

Preferably, the molecular sieve is at least one of ZSM-35 zeolite, Ferrierite zeolite, FU-9 zeolite, ISI-6 zeolite, NU-23 zeolite, Sr-D zeolite, ZSM-57 zeolite and COK-5 zeolite.

According to the present invention, preferably, the molecular sieve is a mixture of a molecular sieve with a FER structure and a molecular sieve with an MFS structure. More preferably, the weight ratio of the molecular sieve with the FER structure to the molecular sieve with the MFS structure is 0.1-10:1, more preferably 1-5:1.

More preferably, the molecular sieve of the FER structure is at least one of ZSM-35 zeolite, Ferrierite zeolite, FU-9 zeolite, ISI-6 zeolite, NU-23 zeolite and Sr-D zeolite, more preferably ZSM-35 zeolite, At least one of Ferrierite zeolite and FU-9 zeolite.

More preferably, the molecular sieve with MFS structure is at least one of ZSM-57 zeolite and COK-5 zeolite.

According to a preferred embodiment of the present invention, preferably the molecular sieve of the FER structure is a mixture of ZSM-35 zeolite and Ferrierite zeolite, more preferably the weight ratio of the two is 2-5:1; the molecular sieve of the MFS structure is The mixture of ZSM-57 zeolite and COK-5 zeolite, more preferably the weight ratio of the two is 2-5:1.

In the present invention, the silicon-aluminum atomic molar ratio (Si/Al) of the molecular sieve may be 0.1-100:1; preferably 30-80:1.

According to the present invention, preferably, based on the total weight of the active component coating, the active component coating contains 54-90% by weight of molecular sieve and 10-46% by weight of matrix.

According to the present invention, preferably, based on the total weight of the catalyst, the content of the active component coating is 15-30% by weight.

According to the invention, the structured support can be used to provide a catalyst bed in a fixed bed reactor. The carrier with regular structure can be a whole carrier block with a hollow channel structure formed inside, a catalyst coating can be distributed on the inner wall of the channel, and the channel space can be used as a fluid flow space. Preferably, the structured carrier is selected from a monolithic carrier with a parallel channel structure open at both ends. The structured carrier may be a honeycomb structured carrier with honeycomb-shaped openings in the cross-section (referred to as honeycomb carrier).

According to the present invention, preferably, the pore density of the cross-section of the regular structure carrier is 6-140 holes/cm2, preferably 20-100 holes/cm2; the cross-sectional area of each hole is 0.4-10 mm2, It is preferably 2-7 square millimeters; the opening ratio is 50-80%. The shape of the hole can be square (or winged square, that is, there are wings with vertical sides facing inward at the center of the four sides in the square hole, and its length is 1/5-2/5 of the side length of the square), regular triangle, regular six One of polygonal, circular and corrugated.

According to the present invention, preferably, the regular structure support may be selected from at least one of cordierite honeycomb support, mullite honeycomb support, alumina honeycomb support and metal alloy honeycomb support.

According to the present invention, preferably, the substrate may be selected from at least one of alumina, silica, amorphous silica-alumina, zirconia, titania, boria and alkaline earth metal oxides.

Catalyst of the present invention can be prepared by various methods, as long as can prepare the catalyst of aforementioned requirement of the present invention, for the present invention, preferred catalyst of the present invention is prepared according to the following steps: (1) molecular sieve and aqueous solvent are mixed and ground, Obtaining the molecular sieve slurry, the molecular sieve is a molecular sieve having a ten-membered ring two-dimensional elliptical pore structure; (2) mixing the molecular sieve slurry with a matrix source to form an active component coating slurry; (3) using the active component The sub-coating slurry coats the structured support and is dried and fired.

According to the present invention, preferably, the addition amount of described matrix source and described molecular sieve makes in the active component coating obtained, take the total weight of this active component coating as a basis, the content total amount of matrix is 5- 50% by weight, and the content of molecular sieve is 50-95% by weight.

In the method provided by the present invention, the matrix source is used to provide the matrix in the prepared active component, which is not particularly required in the present invention. It should be noted that when the matrix is silica and/or alumina, although the molecular sieve contains alumina and silica, the amount of silica and alumina contained in the molecular sieve is still counted as the The amount of molecular sieve, excluding silica and alumina. That is, the content of each component in the active component prepared by the method provided by the invention is calculated according to the feeding amount.

According to the present invention, the molecular sieve particle diameter _d90 in the molecular sieve slurry in step (1) is 1-10 microns, preferably 5-10 microns, the solid content of the molecular sieve slurry is 15-70% by weight, and the aqueous solvent for deionized water.

According to the present invention, preferably, based on the total weight of the active component coating slurry obtained in step (2), the content of the molecular sieve is 3-60% by weight, and the matrix source on a dry basis The total content is 0.3-18% by weight.

According to the present invention, the active component coating slurry in step (2) may further contain a dispersant, and the weight ratio of the dispersant to the molecular sieve is less than 0.2 and greater than 0; preferably 0.0005-0.015:1.

According to the present invention, the dispersant in step (2) is selected from compounds containing at least one of polyhydroxy, polyvinyl and polycarboxylic acid groups, such as polyethylene glycol, glycerol, polyvinyl alcohol Or one or more of polyacrylic acid, preferably polyethylene glycol and/or polyacrylic acid.

According to the present invention, in step (3), the catalyst provided by the present invention can be prepared by distributing the active component coating slurry on the inner surface and/or outer surface of the structured carrier by various coating methods. The coating method can be water coating method, dipping method or spraying method. The specific operation of coating can be carried out with reference to the method described in CN1199733C. The coating temperature is preferably 10-70°C, more preferably 15-35°C, the coating pressure is preferably -0.04 MPa to 0.4 MPa, and the coating time is preferably 0.1-100 seconds.

According to the present invention, the structured carrier coated with the active component coating slurry is dried and calcined. The drying method and conditions are well known to those skilled in the art, for example, the drying method may be air drying, oven drying, and blast drying. Preferably, in step (3), the drying temperature can be from room temperature to 300°C, preferably 100-200°C; the drying time is at least 0.5 hours, preferably 1-10 hours.

According to the present invention, the conditions of the calcination in step (3) can also be known to those skilled in the art, generally speaking, the temperature of the calcination is 400-800°C, preferably 500-700°C; The time is at least 0.5 hours, preferably 1-10 hours.

According to the present invention, the types of molecular sieves have been described in detail above, and will not be repeated here.

According to the present invention, when the matrix is silicon oxide, the matrix source may be a silicon oxide source, preferably the silicon oxide source is silicon oxide or a natural ore with a silicon oxide content greater than 45% by weight. Preferably, the silica source may be at least one of silica sol, layered clay, diatomaceous earth, expanded perlite, chert, hydrolyzed silica, macroporous silica and silica gel.

According to the present invention, when the substrate is alumina, the substrate source may be an alumina source, and the alumina source may be a substance that can be converted into alumina under the calcination conditions in step (3). Preferably, the alumina source is one or more of pseudoboehmite, hydrated alumina and aluminum sol; the hydrated alumina is boehmite, pseudoboehmite, trihydrate At least one of alumina and amorphous aluminum hydroxide.

The present invention also provides a catalyst prepared by the method provided by the present invention.

According to the present invention, the catalyst comprises a regular structure carrier and an active component coating distributed on the inner surface and/or outer surface of the regular structure carrier; based on the total weight of the catalyst, the content of the active component coating is 10-50% by weight; based on the total weight of the active component coating, the total content of the active component coating containing silicon oxide and aluminum oxide is 5-50% by weight, and the content of molecular sieve is 50-95% % by weight; the molecular sieve is a molecular sieve with a ten-membered ring two-dimensional elliptical pore structure. Preferably, the total content of silicon oxide and aluminum oxide is 5-20% by weight, and the content of molecular sieve is 80-95% by weight.

The present invention also provides a method for producing propylene by catalytic cracking of naphtha, the method comprising: under the reaction conditions of catalytic cracking of naphtha, contacting naphtha and water with a catalyst to obtain a propylene product, wherein the catalyst Catalyst provided by the present invention.

According to the present invention, preferably, the reaction conditions for catalytic cracking of naphtha include: a temperature of 520-590° C., a pressure of 0.1-0.2 MPa, and a water/oil feed weight ratio of 0.3-2, preferably 0.4-1.7 ; The weight hourly space velocity of the naphtha feed is 2-40h ^-1 , preferably 2.3-36.5h ^-1 based on the active component coating.

According to the present invention, preferably, the naphtha contains 0.5-1.5% by weight of olefins, 40-60% by weight of alkanes, 20-40% by weight of naphthenes and 10-20% by weight of aromatics.

The present invention will be described in detail below by way of examples.

The properties of gas phase products in the following examples were determined by gas chromatography using an instrument of HP6890 type from Agilent Company. Yield and selectivity were calculated by the following formulas:

Yield = (target product (C ₂ ⁼ +C ₃ ⁼ ) generated amount/reactant feed amount) × 100%

Selectivity = (target product (C ₂ ⁼ ~ C ₄ ⁼ ) formation amount/reactant conversion amount) × 100%

Example 1

This example is used to illustrate the preparation method of the catalyst provided by the present invention and the method for producing propylene by catalytic cracking of naphtha.

(1) Preparation of catalyst. Mix 56.2 grams of ZSM-35 molecular sieve (Nanjing Jicang Nano Technology Co., Ltd., Si/Al molar ratio = 30:1) with 56.2 grams of deionized water, and wet ball mill to form a molecular sieve slurry. The molecular sieve particle diameter d ₉₀ =10 microns, The solids content was 50% by weight. Add 28.4 grams of aluminum sol (containing 22% by weight of alumina, produced by Sinopec Catalyst Qilu Branch) in the slurry, stir for 10 minutes, add 1.5 grams of polyethylene glycol solution (the weight percentage of polyethylene glycol in the polyethylene glycol solution 2% by weight), stirred for 20 minutes to obtain a catalyst coating slurry (coating slurry).

The active component coating slurry is coated with a cordierite honeycomb carrier (the carrier pore density is 100 holes/square centimeter, the cross-sectional area of each hole is 7 square millimeters, the opening ratio is 80%, and the shape of the holes is a square), Drying at 120° C. for 5 hours and calcining at 500° C. for 5 hours gave a catalyst in which the coating content of the active component was 15% by weight.

The coating composition of the active component based on the feed calculation: the content of ZSM-35 molecular sieve is 90% by weight, and the content of matrix (aluminum oxide) is 10% by weight.

(2) Propylene production. The catalyst prepared in (1) was used as a catalyst bed to form a structured reactor, wherein the total weight of the active component coating was 62.5 grams. Naphtha (containing 1% by weight of olefins, 56% by weight of alkanes, 32% by weight of naphthenes, 11% by weight of aromatics, and 0.5 μg/g of basic nitrogen) and water were preheated at 250°C and injected into the above-mentioned regular structure reactor. Wherein, the heavy hourly space velocity of naphtha injection (the weight of naphtha relative to the total weight of the active component coating) is 2.3hr ^-1 , and the weight ratio of water/oil feed is 0.46. The reaction temperature is 520° C., and the pressure is 0.1 MPa. The reaction results are shown in Table 1.

Example 2

This example is used to illustrate the preparation method of the catalyst provided by the present invention and the method for producing propylene by catalytic cracking of naphtha.

(1) Preparation of catalyst. Mix 32 grams of Ferrierite zeolite powder (self-made, Si/Al molar ratio = 50:1) with 20 grams of deionized water, and wet ball mill to form a slurry. The diameter of molecular sieve particles in the slurry is d ₉₀ =8 microns; add 150 grams of Peptize pseudo-boehmite (containing 18% by weight of alumina, the pH value is 2.8, the product of Sinopec Catalyst Qilu Branch), stirred for 15 minutes; added 3.2 grams of polyacrylic acid solution (the weight percent of polyacrylic acid in the polyacrylic acid solution is 1 weight percent) %), stirred for 30 minutes to obtain a catalyst coating slurry.

The active component coating slurry is coated with a cordierite honeycomb carrier (the carrier pore density is 80 holes/square centimeter, the cross-sectional area of each hole is 5 square millimeters, the opening rate is 60%, and the shape of the hole is circular) , dried at 120° C. for 5 hours and calcined at 500° C. for 5 hours to obtain a catalyst, wherein the active component coating content is 20% by weight.

The coating composition of the active component based on the feed calculation: the Ferrierite zeolite content is 54% by weight, and the matrix (aluminum oxide) content is 46% by weight.

(2) Propylene production. The catalyst prepared in (1) was used as a catalyst bed to form a structured reactor, wherein the total weight of the active component coating was 59 grams. Naphtha (containing 1% by weight of olefins, 56% by weight of alkanes, 32% by weight of naphthenes, 11% by weight of aromatics, and 0.4 μg/g of basic nitrogen) and water were preheated at 250°C and injected into the above-mentioned regular structure reactor. Wherein, the heavy hourly space velocity of naphtha injection (the weight of naphtha relative to the total weight of active component coating) is 36.5hr ^-1 , and the water/oil feed weight ratio is 0.96. The reaction temperature is 570° C. and the pressure is 0.1 MPa. The reaction results are shown in Table 1.

Example 3

This example is used to illustrate the preparation method of the catalyst provided by the present invention and the method for producing propylene by catalytic cracking of naphtha.

(1) Preparation of catalyst. Mix 70 grams of ZSM-57 zeolite (self-made, Si/Al molar ratio = 80:1) with 60 grams of distilled water, and wet ball mill it into a slurry. The diameter of molecular sieve particles in the slurry is d ₉₀ =5 microns; add 143 grams of acid to the slurry Silica sol (containing silicon oxide 21% by weight, product of Sinopec Catalyst Qilu Branch Company), stirred for 60 minutes; Added polyethylene glycol and polyacrylic acid mixed solution 12.6 grams (polyethylene glycol and polyacrylic acid percentage by weight are respectively 3% by weight and 5% by weight %), stirred for 30 minutes to obtain the catalyst coating slurry.

The active component coating slurry is coated with a cordierite honeycomb carrier (the carrier pore density is 20 holes/square centimeter, the cross-sectional area of each hole is 2 square millimeters, the porosity is 75%, and the shape of the hole is circular) , dried at 120° C. for 5 hours and calcined at 500° C. for 5 hours to obtain a catalyst, wherein the active component coating content is 30% by weight.

The coating composition of the active component based on the feeding calculation: the content of ZSM-57 zeolite is 70% by weight, and the content of matrix (silicon oxide) is 30% by weight.

(2) Propylene production. The catalyst prepared in (1) was used as a catalyst bed to form a structured reactor, wherein the total weight of the active component coating was 100 grams. Naphtha (containing 1% by weight of olefins, 56% by weight of alkanes, 32% by weight of naphthenes, 11% by weight of aromatics, and 0.6 μg/g of basic nitrogen) and water were preheated at 250°C and injected into the above-mentioned regular structure reactor. The heavy hourly space velocity of naphtha injection (the weight of naphtha relative to the total weight of the active component coating) is 4.6 hr ⁻¹ , and the weight ratio of water/oil feed is 1.61. The reaction temperature is 590° C. and the pressure is 0.2 MPa. The reaction results are shown in Table 1.

Example 4

According to the method cracking naphtha of embodiment 3, difference is, molecular sieve is replaced by ZSM-35 zeolite (silicon-aluminum atomic molar ratio is 30) and COK-5 zeolite (silicon-aluminum atomic molar ratio is 50) in the catalyst, and two The weight ratio of the latter is 1:1.

Example 5

According to the method cracking naphtha of embodiment 3, difference is, molecular sieve is replaced by Ferrierite zeolite (silicon-aluminum atomic molar ratio is 50) and ZSM-57 zeolite (silicon-aluminum atomic molar ratio is 80) in the catalyst, and both The weight ratio is 2:1.

Example 6

According to the method cracking naphtha of embodiment 3, difference is, molecular sieve is replaced by FU-9 zeolite (silicon-aluminum atomic molar ratio is 50) and ZSM-57 zeolite (silicon-aluminum atomic molar ratio is 30) in the catalyst, and two The weight ratio of the latter is 5:1.

Example 7

According to the method cracking naphtha of embodiment 4, difference is, ZSM-35 zeolite is made of ZSM-35 zeolite (silicon-aluminum atomic molar ratio is 30) and Ferrierite zeolite (silicon-aluminum atomic molar ratio is 30) in the molecular sieve in the catalyst The mixture is replaced, and the weight ratio of the two is 3:1; COK-5 zeolite is replaced by the mixture of ZSM-57 zeolite (silicon-aluminum atomic molar ratio is 50) and COK-5 zeolite (silicon-aluminum atomic molar ratio is 50), two The weight ratio of the latter is 4:1.

Comparative example 1

(1) Preparation of catalyst. Mix 56.2 grams of ZSM-5 zeolite (manufactured by Nankai University, Si/Al molar ratio = 30:1) with 56.2 grams of deionized water, and wet ball mill to form a molecular sieve slurry. The particle diameter of the molecular sieve is d ₉₀ =10 microns, and the solid content is 50 weight%. 28.4 grams of aluminum sol (containing 22% by weight of alumina, produced by Sinopec Catalyst Qilu Branch) was added to the slurry, and stirred for 20 minutes to obtain a mixture slurry which was then extruded.

The coating composition of the active component based on the feed calculation: the ZSM-5 zeolite content is 90% by weight, and the matrix (aluminum oxide) content is 10% by weight.

(2) Propylene production. The catalyst prepared in (1) is used as a catalyst bed to form a fixed-bed reactor. Naphtha (containing 1% by weight of olefins, 56% by weight of alkanes, 32% by weight of naphthenes, 11% by weight of aromatics, and 0.5 μg/g of basic nitrogen) and water are preheated at 250°C and injected into the above-mentioned fixed bed reactor. The weight hourly space velocity of naphtha injection (relative to the total weight of the catalyst bed) is 4.6 hr ^-1 , and the water/oil feed weight ratio is 1.61. The reaction temperature is 590° C., and the pressure is 0.1 MPa. The reaction results are shown in Table 1.

Comparative example 2

According to the method of embodiment 1, the difference is that the catalyst used is to contain 18% by weight of ZSM-35 zeolite (silicon-aluminum atomic molar ratio is 30) and 82% by weight of the substrate (aluminum oxide) particle diameter is 2mm, length 5mm strip catalyst.

The yield of (C ₂ ^＝ +C ₃ ^＝ ) and the selectivity of (C ₂ ^＝ ～C ₄ ^＝ ) were calculated, and the results are shown in Table 1.

Comparative example 3

According to the method of Example 1, the difference is that the active component molecular sieve of the active component coating in the structured catalyst is Beta zeolite (silicon-aluminum atomic molar ratio is 30), and the rest are the same.

The yield of (C ₂ ^＝ +C ₃ ^＝ ) and the selectivity of (C ₂ ^＝ ～C ₄ ^＝ ) were calculated, and the results are shown in Table 1.

Table 1

As can be seen from the data results in Table 1, the catalyst provided by the present invention adopts a regular structure carrier and contains an active component coating with a ten-membered ring two-dimensional elliptical pore structure, which is a kind of FER or MFS structure. In the catalytic cracking of naphtha to produce propylene, high ethylene and propylene yields can be obtained, and the propylene/ethylene ratio is greater than 1, which can realize more propylene production.

Claims (16)

1. A catalyst for producing propylene by catalytic cracking of naphtha, the catalyst comprising: a regular structure carrier and an active component coating distributed on the inner surface and/or outer surface of the regular structure carrier; based on the total weight of the catalyst , the content of the active component coating is 10-50% by weight; based on the total weight of the active component coating, the active component coating contains 50-95% by weight of molecular sieve and 5-50 % by weight of matrix; the molecular sieve is a molecular sieve with a ten-membered ring two-dimensional elliptical pore structure, and the molecular sieve with a ten-membered ring two-dimensional elliptical pore structure is a mixture of a molecular sieve with a FER structure and a molecular sieve with an MFS structure, wherein , the weight ratio of the molecular sieve with the FER structure to the molecular sieve with the MFS structure is 0.1-10:1. 2. catalyst according to claim 1, wherein, the weight ratio of the molecular sieve of FER structure and the molecular sieve of MFS structure is 1-5:1; The molecular sieve of the FER structure is at least one of ZSM-35 zeolite, Ferrierite zeolite, FU-9 zeolite, ISI-6 zeolite, NU-23 zeolite and Sr-D zeolite; the molecular sieve of the MFS structure is ZSM-57 zeolite and At least one of the COK-5 zeolites. 3. The catalyst according to claim 1, wherein the molecular sieve of the FER structure is one of ZSM-35 zeolite, Ferrierite zeolite and FU-9 zeolite. 4. The catalyst according to claim 2, wherein the molecular sieve of the FER structure is a mixture of ZSM-35 zeolite and Ferrierite zeolite; the molecular sieve of the MFS structure is a mixture of ZSM-57 zeolite and COK-5 zeolite. 5. The catalyst according to any one of claims 1-4, wherein, based on the total weight of the active component coating, the active component coating contains 54-90% by weight of molecular sieves and 10 - 46% by weight of matrix. 6. The catalyst according to any one of claims 1-4, wherein, based on the total weight of the catalyst, the content of the active component coating is 15-30% by weight. 7. The catalyst according to claim 1, wherein the structured support is selected from a monolithic support having a parallel channel structure open at both ends. 8. The catalyst according to claim 7, wherein the pore density of the cross-section of the regular structure carrier is 6-140 holes/square centimeter, the cross-sectional area of each hole is 0.4-10 square millimeters, and the opening ratio is 50 -80%. 9. The catalyst according to any one of claims 1, 7 and 8, wherein the regular structure carrier is selected from cordierite honeycomb carrier, mullite honeycomb carrier, alumina honeycomb carrier and metal alloy honeycomb carrier at least one. 10. The catalyst according to claim 1, wherein the substrate is selected from at least one of alumina, silica, amorphous silica-alumina, zirconia, titania, boria and alkaline earth metal oxides. 11. A method for preparing a catalyst for the catalytic cracking of naphtha according to any one of claims 1-10 to produce propylene, the method comprising: (1) mixing and grinding the molecular sieve and an aqueous solvent to obtain a molecular sieve slurry; (2) mixing the molecular sieve slurry with a matrix source to form an active component coating slurry; (3) Coating the structured support with the active component coating slurry, drying and firing. 12. The method according to claim 11, wherein, in step (1), the molecular sieve particle diameter _d90 in the molecular sieve slurry is 1-10 microns, and the solid content of the molecular sieve slurry is 15-70% by weight, so The aqueous solvent is deionized water. 13. The method according to claim 11, wherein, in step (2), the active component coating slurry further contains a dispersant, and the weight ratio of the dispersant to the molecular sieve is less than 0.2 and greater than zero. 14. A catalyst prepared by the process of any one of claims 11-13. 15. A method for producing propylene by catalytic cracking of naphtha, the method comprising: under the reaction conditions of catalytic cracking of naphtha, contacting naphtha and water with a catalyst to obtain a propylene product, characterized in that the catalyst comprises The catalyst according to any one of claims 1-10 and 14. 16. The method according to claim 15, wherein the catalytic cracking reaction conditions of the naphtha include: a temperature of 520-590° C., a pressure of 0.1-0.2 MPa, and a water/oil feed weight ratio of 0.3-2; The catalyst is calculated based on the active component coating, and the weight hourly space velocity of the naphtha feed is 2-40h ^-1 .