CN112206810B

CN112206810B - Preparation method and rare earth Y-type molecular sieve

Info

Publication number: CN112206810B
Application number: CN201910612785.0A
Authority: CN
Inventors: 王成强; 罗一斌; 郑金玉; 舒兴田
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2019-07-09
Filing date: 2019-07-09
Publication date: 2022-01-04
Anticipated expiration: 2039-07-09
Also published as: CN112206810A

Abstract

The invention discloses a method for carrying out hydrothermal roasting treatment on a rare earth NaY molecular sieve under the atmosphere environment of externally applying pressure and externally adding an aqueous solution containing an acidic substance or an alkaline substance, and recovering a product, wherein the apparent pressure of the atmosphere environment is 0.01-1 MPa and the atmosphere environment contains 1-100% of water vapor.

Description

Preparation method and rare earth Y-type molecular sieve

Technical Field

The invention relates to a preparation method and a rare earth Y-type molecular sieve obtained by the preparation method.

Background

Catalytic cracking is the most important production technology in today's refineries, and catalytic cracking units are used to convert heavy oils and resids into gasoline, diesel, and light gas components. In the industry, a catalytic cracking unit must comprise two parts of reaction and high-temperature catalyst regeneration, so that the catalyst needs to consider the factors of catalytic activity, selectivity and the like, and compared with other types of molecular sieves, the Y-type molecular sieve is more used in the cracking reaction and is used as an active component of the catalytic cracking catalyst, and the main function of the Y-type molecular sieve in the catalytic cracking catalyst is responsible for producing gasoline range molecular products.

The rare earth exchanged rare earth Y molecular sieve is a high-activity component of the catalytic cracking catalyst. Rare earth ions in the rare earth Y molecular sieve migrate from the supercage to the sodalite cage and form an oxygen-bridge-containing multi-core cation structure, so that the stability of an acid center of the molecular sieve in a high-temperature hydrothermal environment is improved, the cracking activity and the activity stability of the molecular sieve catalyst are improved, and the heavy oil conversion activity and the selectivity of the catalyst are improved. However, when the NaY molecular sieve is ion exchanged with an aqueous solution of a rare earth salt, hydrated rare earth ions having a diameter of about 0.79nm are difficult to enter the sodalite cage through the six-membered ring window (having a diameter of about 0.26nm) of the Y molecular sieve. Therefore, the surrounding material must be removed by calcination during the preparation of the rare earth Y molecular sieveThe hydrated layer around the rare earth ions allows the rare earth ions to enter into the sodalite cages and into the hexagonal prisms, and the sodium ions in the cages also migrate out into the supercages by virtue of the calcination process, in short, the calcination results in accelerated intracrystalline exchange between solid ions, which is the molecular sieve with other cations such as NH in aqueous solution₄ ⁺、RE³⁺Exchange of (2) and reduction of Na of molecular sieves⁺The content creates conditions (USP 3402996). Therefore, how to promote the migration of rare earth ions and increase the occupancy rate of rare earth ions on the position (in a small cage) of a lockable cation directly relates to the performance of the rare earth Y molecular sieve and influences the activity stability of the catalyst taking the rare earth Y molecular sieve as an active component. In order to promote the migration of rare earth ions into sodalite cages, high-temperature roasting or high-temperature hydrothermal roasting is generally adopted in the industry, however, in addition to the more severe requirements on the material of the industrial roasting furnace, the rare earth ions which are locked have the tendency to return to large cages (Zeolite, 6(4), 235, 1986). The current technical situation of industrial roasting is as follows: NaY and RE³⁺The rare earth NaY (sodium oxide content is 4.5-6.0%) molecular sieve filter cake obtained after exchange needs to be subjected to solid ion exchange at high temperature roasting (550-.

The current major problem is that the degree of solid-state ion exchange needs to be further improved. Therefore, how to make as many rare earth ions migrate to the small cage position as possible at a limited calcination temperature to further improve the stability of the molecular sieve becomes a great technical problem to be solved in industry.

CN1026225C discloses a method for preparing rare earth Y molecular sieve, which comprises the steps of mixing NaY molecular sieve with RE³⁺After ion exchange in water solution, roasting in 100% flowing water vapor at 450-600 deg.c for 1-3 hr.

The method comprises the steps of carrying out contact treatment on a NaY molecular sieve and a rare earth salt solution or a mixed solution of ammonium salt and a rare earth salt solution, filtering, washing with water, drying and then carrying out roasting treatment to obtain a rare earth sodium Y molecular sieve; then pulping the rare earth sodium Y molecular sieve, contacting with an ammonium salt solution, then not filtering, mixing with a rare earth salt solution, adjusting the pH value of the slurry by using alkaline liquid to perform rare earth deposition, or pulping the rare earth sodium Y molecular sieve, then performing contact treatment on the pulped rare earth sodium Y molecular sieve and a mixed solution of the ammonium salt solution and the rare earth salt solution, adjusting the pH value of the slurry by using the alkaline liquid to perform rare earth deposition, filtering and drying, and then performing secondary roasting treatment to obtain the rare earth Y molecular sieve. The method needs to pass through the processes of two-phase exchange and two-baking and combined deposition of rare earth.

Disclosure of Invention

The invention aims to provide a simple preparation method of a rare earth Y-type molecular sieve, which can enable rare earth ions to migrate to small cage positions as much as possible.

The preparation method of the rare earth Y-type molecular sieve provided by the invention comprises the following steps: the method comprises the steps of carrying out hydrothermal roasting treatment on a rare earth NaY molecular sieve under the atmosphere environment of externally applied pressure and externally added aqueous solution containing acidic substances or alkaline substances, and recovering a product, wherein the apparent pressure of the atmosphere environment is 0.01-1 MPa and the atmosphere environment contains 1-100% of water vapor.

The preparation method of the invention, wherein the rare earth NaY molecular sieve is preferably obtained by carrying out contact treatment on the NaY molecular sieve and a rare earth salt solution or a mixed solution of the rare earth salt solution and an ammonium salt, filtering, washing and drying. The rare earth salt solution contains chloride aqueous solution containing one or more of lanthanum, cerium, praseodymium and neodymium ions. The ammonium salt is selected from any one or a mixture of ammonium chloride, ammonium nitrate, ammonium carbonate and ammonium bicarbonate. The contact treatment is carried out on the NaY molecular sieve and a rare earth salt solution or a mixed solution of a rare earth salt solution and an ammonium salt, and the process is that the NaY molecular sieve and the rare earth salt solution or the mixed solution of the rare earth salt solution and the ammonium salt are exchanged for at least 0.3 hour at the temperature of room temperature to 100 ℃ under the conditions that the pH value of slurry is 3.0-5.0, the weight ratio of a water sieve is 5-30.

In the method of the present invention, the hydrothermal calcination treatment is carried out in an atmosphere of externally applied pressure and externally added water. The atmosphere is obtained by externally applying pressure and water, preferably apparent pressure is 0.1-0.8 MPa, more preferably apparent pressure is 0.3-0.6 MPa, preferably 30-100% water vapor, more preferably 60-100% water vapor. The external pressure is applied to the hydrothermal roasting treatment of the prepared material from the outside, and for example, the external pressure may be applied by introducing an inert gas from the outside to maintain a certain back pressure. The amount of water applied to the outside is based on 1-100% of water vapor satisfying the atmospheric environment.

The process of the invention may also comprise a step followed by an ammonium exchange. The ammonium exchange is carried out for at least 0.3 hour at room temperature to 100 ℃, wherein the weight ratio of the rare earth sodium Y molecular sieve to ammonium salt and water is 1: (0.05-0.5): (5-30).

The rare earth NaY molecular sieve is subjected to roasting treatment under the conditions that the apparent pressure is 0.01-1 Mpa, the water vapor atmosphere is 1-100% and acid substances or alkaline substances exist; preferably, the calcination is carried out at 300-800 deg.C under 0.1-0.8 Mpa in 30-100% steam atmosphere for at least 0.1 hour, and more preferably at 400-600 deg.C under 0.3-0.6 Mpa in 60-100% steam atmosphere for 1-3 hours. The acidic substance comprises one or more of ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, ammonium dihydrogen carbonate, ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, hydrochloric acid, sulfuric acid, nitric acid and the like, wherein one or more of ammonium bicarbonate, ammonium dihydrogen carbonate, ammonium phosphate, ammonium dihydrogen phosphate and diammonium hydrogen phosphate is preferred; the alkaline substance is selected from one or more of ammonia water, buffer solution of ammonia water and ammonium chloride, sodium hydroxide, sodium metaaluminate, sodium carbonate, sodium bicarbonate, etc., wherein the buffer solution of ammonia water or ammonia water and ammonium chloride is preferred.

The preparation method of the invention can further comprise the steps of exchanging the product rare earth sodium Y molecular sieve with ammonium salt water solution, filtering, washing and drying to obtain the rare earth Y-type molecular sieve. The exchange treatment is to exchange for at least 0.3 hour at room temperature to 100 ℃, wherein the weight ratio of the rare earth sodium Y molecular sieve to ammonium salt and water is 1: (0.05-0.5): (5-30).

The method is simple and easy to operate, and the prepared rare earth Y molecular sieve has unique pore size distribution characteristics, namely, at least two kinds of mesoporous pore size distributions of 2-3 nm and 3-4 nm exist, the mesoporous volume is more than 0.03cc/g (mesoporous means pores with the pore size distribution of 2-50 nm), the rare earth content is calculated by rare earth oxide, the rare earth content is 2-18 wt%, preferably 8-15 wt%, the unit cell constant is 2.440-2.470 nm, and the crystallinity is 30-60%. Preferably, the mesoporous volume is 0.031cc/g to 0.037cc/g, which is reflected in a hysteresis loop having a larger area as shown by the curve a in FIG. 2.

For the rare earth-containing Y-type molecular sieve, in an X-ray diffraction pattern, a peak with 2 theta being 11.8 +/-0.1 degrees can be used for representing the distribution condition of the rare earth in a small cage, I₁Represents the peak intensity thereof; the peak 2 theta of 12.3 +/-0.1 degrees can be used for characterizing the rare earth distribution in a supercage, I₂Represents the peak intensity, I₁And I₂The ratio of (A) can be used for representing the migration degree of the rare earth ions from the supercages to the small cages, and the higher the ratio is, the better the migration degree is, and the worse is. In the prior art, if the rare earth Y-type molecular sieve obtained by conventional atmospheric pressure steam roasting is adopted, the intensity I of a peak with 2 theta of 11.8 +/-0.1 degrees in an X-ray diffraction pattern₁Intensity of peak 12.3 + -0.1 DEG with 2 theta₂The ratio of (A) is generally < 4.

The molecular sieve prepared by the method has the intensity I of a peak with the 2 theta of 11.8 +/-0.1 degrees in an X-ray diffraction pattern₁Intensity of peak 12.3 + -0.1 DEG with 2 theta₂The ratio of (A) to (B) is more than or equal to 4.0; preferably, the intensity I of the peak with 2 θ of 11.8 ± 0.1 ° in the X-ray diffraction pattern is₁Intensity of peak 12.3 + -0.1 DEG with 2 theta₂The ratio of (A) to (B) is 4.5-6.0.

The invention adopts pressurized hydrothermal roasting for adjusting atmosphere, obviously increases the richness of mesoporous pores of the Y molecular sieve, forms mesoporous pores of the molecular sieve to a certain degree, improves the accessibility, improves the utilization rate of active centers, and can become a new way for expanding pores of molecular sieve crystals with low cost and low emission. The rare earth Y-type molecular sieve treated by the regulated atmosphere pressure roasting has higher cracking activity stability, the coke selectivity is reduced, and the method has wide application prospect in the field of heavy oil catalysis.

Drawings

FIG. 1 is the BJH pore size distribution curve of the rare earth Y-type molecular sieve prepared by the invention. The a curve represents sample PBY-1 and the b curve represents comparative sample DBY-1.

FIG. 2 is the adsorption and desorption distribution curve of the rare earth Y-type molecular sieve prepared by the invention. The c-curve represents sample PBY-1 and the d-curve represents comparative sample DBY-1.

FIG. 3 is the X-ray diffraction (XRD) curve of the rare earth Y-type molecular sieve prepared by the invention.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.

In each example, the product unit cell constant and crystallinity were determined by X-ray diffraction (XRD) and the product BJH pore size distribution curve was measured by low temperature nitrogen desorption.

Example 1

Mixing 100g NaY molecular sieve and 1800g deionized water, pulping, adding 20ml 357gRE₂O₃And (3) mixing the rare earth chloride salt solution and 2g of ammonium chloride solid, heating to 70 ℃ after uniform stirring, adjusting the pH value of the slurry to 4.5 by using dilute hydrochloric acid, and stirring for 1 hour at constant temperature. After filtering, washing and drying, applying pressure outside and adding 7g of ammonia water, and then carrying out hydrothermal roasting treatment for 2 hours at 500 ℃ under the apparent pressure of 0.3Mpa and in the atmosphere of 100% of water vapor to obtain the rare earth NaY molecular sieve recorded as PBY-1.

PBY-1 the chemical composition of the molecular sieve is 10.3 wt% rare earth oxide.

In fig. 1, the curve a is a pore size distribution curve calculated by a sample PBY-1 according to a BJH model, and it can be seen that at least 2 kinds of mesoporous pore size distributions exist, including that one kind of mesoporous pore size distribution exists at 2-3 nm and the other kind of mesoporous pore size distribution exists at 3-4 nm.

The curve c in FIG. 2 is the absorption and desorption curve of the sample PBY-1, and it can be seen that it has a hysteresis loop with a large area, indicating that the sample PBY-1 has a rich mesoporous structure.

FIG. 3 is an XRD spectrum of PBY-1, showing that sample PBY-1 has a phase pure FAU crystal structure without the formation of heterocrystals.

The XRD results are shown in Table 1.

Comparative examples 1 to 1

This comparative example illustrates the process and results of atmospheric hydrothermal calcination of a rare earth Y-type molecular sieve in conventional technology.

The same as example 1, except that the calcination condition was atmospheric pressure and no ammonia was added.

Mixing 100g NaY molecular sieve and 1800g deionized water, pulping, adding 20ml 357gRE₂O₃And (3) mixing the rare earth chloride salt solution and 2g of ammonium chloride solid, heating to 70 ℃ after uniform stirring, adjusting the pH value of the slurry to 4.5 by using dilute hydrochloric acid, and stirring for 1 hour at constant temperature. Filtering, washing, drying, performing hydrothermal roasting treatment for 2 hours at 500 ℃ under the apparent pressure of 0Mpa in the atmosphere of 100% water vapor to obtain the rare earth NaY molecular sieve marked as DBY-1.

The chemical composition of the DBY-1 molecular sieve is 10.1 weight percent of rare earth oxide.

The XRD and pore parameter results are shown in table 1.

In the graph of fig. 1, the curve b is a pore size distribution curve calculated by a comparative sample DBY-1 according to a BJH model, and there are mainly 1 kind of mesoporous pore size distribution, that is, there is one kind of mesoporous pore size distribution at 3-4 nm, but there is another kind of mesoporous pore size distribution at 2-3 nm.

In FIG. 2, the curve d is that the absorption and desorption curves of the comparative sample DBY-1 have smaller hysteresis loop area, which indicates that the mesoporous volume is smaller.

The XRD spectrum of the comparative sample DBY-1 is characterized by that of FIG. 3.

The XRD and pore parameter results are shown in table 1.

Comparative examples 1 to 2

This comparative example illustrates the process and results of a rare earth Y-type molecular sieve obtained by hydrothermal calcination at atmospheric pressure with addition of ammonia.

The same as example 1, except that the firing conditions were atmospheric pressure.

Mixing 100g NaY molecular sieve and 1800g deionized water, pulping, adding 20ml 357gRE₂O₃And (3) mixing the rare earth chloride salt solution and 2g of ammonium chloride solid, heating to 70 ℃ after uniform stirring, adjusting the pH value of the slurry to 4.5 by using dilute hydrochloric acid, and stirring for 1 hour at constant temperature. Filtering, washing with water, drying, adding 7g ammonia water, and performing pressurized hydrothermal roasting treatment at 500 deg.C under 0Mpa and 100% steam atmosphere for 2 hr to obtain rare earth NaY molecular sieveDBY-2

The characteristic of the pore diameter distribution curve calculated by the BJH model and the curve of figure 1b, the characteristic of the adsorption and desorption curve and the curve of figure 2d, and the characteristic of the XRD spectrogram and figure 3

The XRD and pore parameter results are shown in table 1.

Example 2

100g of NaY molecular sieve (Changling Branch of China petrochemical catalyst Co., caustic soda 74.1 wt%, crystallinity 89.3%, the same below) and 1000g of deionized water were mixed and slurried, and 16ml of 357gRE was added₂O₃The solution of rare earth chloride salt and 8g of ammonium chloride solid are mixed evenly, heated to 60 ℃, the pH value of the serous fluid is adjusted to 4.0 by dilute hydrochloric acid, and the mixture is stirred for 1.5 hours at constant temperature. After filtering, washing and drying, applying pressure outside, adding ammonium chloride aqueous solution containing 10g of ammonium chloride, and then carrying out pressurized hydrothermal roasting treatment for 0.5h at 430 ℃ and under the apparent pressure of 0.8Mpa and the atmosphere of 100% water vapor to obtain the rare earth NaY molecular sieve with the chemical composition of 8.2 weight percent of rare earth oxide, namely PBY-2 and PBY-2.

PBY-2 has BJH pore size distribution curve, adsorption and desorption curve and XRD spectrum similar to those of FIG. 1a, FIG. 2c and FIG. 3, respectively.

The XRD and pore parameter results are shown in table 1.

Example 3

Mixing 100g NaY molecular sieve and 2200g deionized water, pulping, adding 24ml 357gRE₂O₃The temperature is raised to 70 ℃ after the mixture is evenly stirred, the PH value of the serous fluid is adjusted to 3.5 by dilute hydrochloric acid, and the mixture is stirred for 1 hour at constant temperature. Filtering, washing with water, drying, applying pressure to the outside, adding an ammonium bicarbonate aqueous solution containing 12g of ammonium bicarbonate, and performing hydrothermal roasting treatment for 1.5 hours at 520 ℃ under the apparent pressure of 0.4Mpa in the atmosphere of 100% water vapor to obtain the rare earth NaY molecular sieve PBY-3.

PBY-3 the chemical composition of the molecular sieve is 11.0 wt% rare earth oxide.

PBY-3 has the characteristics of a curve in figure 1, c curve in figure 2 and figure 3 respectively in the BJH pore size distribution curve, adsorption and desorption curve and XRD spectrum.

The XRD and pore parameter results are shown in table 1.

Example 4

Mixing 100g NaY molecular sieve and 2800g deionized water, pulping, adding 28ml 357gRE₂O₃The temperature is raised to 80 ℃ after the mixture is evenly stirred, the PH value of the serous fluid is adjusted to 3.8 by using dilute hydrochloric acid, and the mixture is stirred for 1 hour at constant temperature. Filtering, washing with water, drying, applying pressure to the outside, adding aqueous solution of sodium carbonate containing 9g of sodium carbonate, and then carrying out pressurized hydrothermal roasting treatment for 2h at 580 ℃ under the apparent pressure of 0.5Mpa in the atmosphere of 100% water vapor to obtain the one-way-one-baking rare earth sodium Y molecular sieve recorded as PBY-4.

PBY-4 the chemical composition of the molecular sieve is 12.8 wt% rare earth oxide.

PBY-4 has the characteristics of curve a in figure 1, curve c in figure 2 and figure 3 respectively in the BJH pore size distribution curve, adsorption and desorption curve and XRD spectrum.

The XRD and pore parameter results are shown in table 1.

Example 5

Mixing 100g NaY molecular sieve and 2000g deionized water, pulping, adding 32ml 357gRE₂O₃The temperature is raised to 70 ℃ after the mixture is evenly stirred, the PH value of the serous fluid is adjusted to 4.0 by using dilute hydrochloric acid, and the mixture is stirred for 1 hour at constant temperature. Filtering, washing with water, drying, applying pressure to the outside, adding a buffer solution of ammonium chloride containing 10g of ammonium chloride and ammonia water, and then carrying out pressurized hydrothermal roasting treatment for 1.5h at 550 ℃, under the apparent pressure of 0.4Mpa and under the atmosphere of 100% water vapor to obtain the rare earth NaY molecular sieve recorded as PBY-5.

PBY-5 the chemical composition of the molecular sieve is 13.1 wt% rare earth oxide.

PBY-5 has BJH pore size distribution curve, adsorption and desorption curve and XRD spectrum similar to those of curve a in FIG. 1, curve c in FIG. 2 and curve c in FIG. 3.

The XRD and pore parameter results are shown in table 1.

Example 6

Mixing 100g NaY molecular sieve and 1800g deionized water, pulping, adding 20ml 357gRE₂O₃And (3) mixing the rare earth chloride salt solution and 2g of ammonium chloride solid, heating to 70 ℃ after uniform stirring, adjusting the pH value of the slurry to 4.5 by using dilute hydrochloric acid, and stirring for 1 hour at constant temperature. After filtration, washing with water, drying, pressure was externally applied and 2g of hydrochloric acid and water were added, and thenAnd carrying out pressurized hydrothermal roasting treatment for 2 hours at 430 ℃ and under the apparent pressure of 0.6Mpa in the atmosphere of 100% water vapor to obtain the rare earth NaY molecular sieve recorded as PBY-6.

PBY-6 the chemical composition of the molecular sieve is 10.1 wt% rare earth oxide.

PBY-6 has the characteristics of a curve in the figure, c curve in the figure 2 and figure 3 respectively in the BJH pore size distribution curve, adsorption and desorption curve and XRD spectrum.

The XRD and pore parameter results are shown in table 1.

Comparative example 2-1

This comparative example illustrates the process and results of a rare earth Y-type molecular sieve obtained without a pressurized hydrothermal calcination treatment (i.e., atmospheric hydrothermal calcination).

The same as example 6, except that the calcination conditions were atmospheric pressure and hydrochloric acid was not added.

Mixing 100g NaY molecular sieve and 1800g deionized water, pulping, adding 20ml 357gRE₂O₃The solution of rare earth chloride salt and 2g of ammonium chloride solid are mixed evenly and heated to 70 ℃ to be stirred for 1 hour at constant temperature. Filtering, washing, drying, performing hydrothermal roasting treatment for 2 hours at 430 ℃ under the apparent pressure of 0Mpa in the atmosphere of 100% water vapor to obtain the rare earth NaY molecular sieve DBY-3.

The chemical composition of the DBY-3 molecular sieve is 10.0 weight percent of rare earth oxide.

The XRD and pore parameter results are shown in table 1.

The BJH pore size distribution curve, the adsorption and desorption curve and the XRD spectrogram of DBY-3 have the characteristics of a curve b in figure 1, a curve d in figure 2 and a curve d in figure 3 respectively.

Comparative examples 2 to 2

The same as example 6, except that the firing conditions were atmospheric pressure.

Mixing 100g NaY molecular sieve and 1800g deionized water, pulping, adding 20ml 357gRE₂O₃The solution of rare earth chloride salt and 2g of ammonium chloride solid are mixed evenly and heated to 70 ℃ to be stirred for 1 hour at constant temperature. After filtration, washing with water, drying, 2g of hydrochloric acid and water are added, and thenPerforming hydrothermal roasting treatment for 2 hours at the temperature of 430 ℃ and the apparent pressure of 0Mpa in the atmosphere of 100 percent water vapor to obtain the rare earth NaY molecular sieve which is marked as DBY-4.

The chemical composition of the DBY-4 molecular sieve is 9.8 weight percent of rare earth oxide.

The XRD and pore parameter results are shown in table 1.

The BJH pore size distribution curve, the adsorption and desorption curve and the XRD spectrogram of DBY-4 have the characteristics of the curve in figure 1b, the curve in figure 2d and the curve in figure 3 respectively.

Example 7

Mixing 100g NaY molecular sieve and 1800g deionized water, pulping, adding 20ml 357gRE₂O₃And (3) mixing the rare earth chloride salt solution and 2g of ammonium chloride solid, heating to 70 ℃ after uniform stirring, adjusting the pH value of the slurry to 4.5 by using dilute hydrochloric acid, and stirring for 1 hour at constant temperature. After filtering, washing and drying, externally applying pressure, adding water and 3g of sodium hydroxide solid, and then carrying out hydrothermal roasting treatment for 2 hours at 400 ℃ under the apparent pressure of 0.8Mpa in the atmosphere of 100% water vapor to obtain the rare earth NaY molecular sieve recorded as PBY-7.

PBY-7 the chemical composition of the molecular sieve is 9.9 wt% rare earth oxide.

PBY-7 has BJH pore size distribution curve, adsorption and desorption curve and XRD spectrum similar to those of FIGS. 1, 2 and 3.

The XRD and pore parameter results are shown in table 1.

TABLE 1

As can be seen from table 1, the mesoporous area and the mesoporous volume of the rare earth Y-type molecular sieve prepared in examples 1 to 7 of the method of the present invention are significantly higher than those of the samples in comparative examples 1 to 4, wherein the sample in example 1 is more preferable, which shows that the rare earth Y-type molecular sieve has a significantly mesoporous characteristic and a higher crystallinity, which indicates that the richness of the mesoporous of the Y-type molecular sieve is significantly increased by using pressurized hydrothermal calcination with an adjusted atmosphere to form a certain degree of mesoporous molecular sieve.

Example 8

This example illustrates the cracking performance of heavy oil after hydrothermal aging of rare earth Y-type molecular sieve at 800 deg.C with 100% steam for 17 h.

The PBY-1 sample obtained in example 1 and the DBY-2 sample obtained in comparative example 2 were mixed with ammonium chloride solution for exchange, and Na contained therein was exchanged₂Washing to below 0.3 wt% with O%, filtering, drying, and performing hydrothermal aging treatment at 800 deg.C with 100% water vapor for 17 hr to perform micro-reverse evaluation on heavy oil.

Heavy oil micro-reverse evaluation conditions: the molecular sieve loading is 2g, the raw oil is Wu-MI-Sanqiao heavy oil (properties are shown in Table 2), the oil inlet amount is 1.384g, the reaction temperature is 500 ℃, and the regeneration temperature is 600 ℃. The evaluation results are shown in Table 3.

TABLE 2

Item	VGO
		Density (293K), g/cm³	0.904
Viscosity (373K), mPa.s	9.96
		Carbon residue, wt. -%)	3.0
C,wt.％	85.98
		H,wt.％	12.86
S,wt.％	0.55
		N,wt.％	0.18
Saturated hydrocarbon, wt. -%)	56.56
		Aromatic hydrocarbons, wt. -%)	24.75
Gum, wt. -%)	18.75
		Asphaltenes, wt. -%)	0.44
Fe,μg/g	5.3
		Ni,μg/g	5.0
V,μg/g	0.8
		Cu,μg/g	0.04
Na,μg/g	1.2

TABLE 3

Sample numbering	PBY-1	DBY-2	PBY-6	DBY-4
					Ratio of agent to oil	1.45	1.45	1.45	1.45
Material balance/m%
					Dry gas	1.23	1.28	1.12	1.05
Liquefied gas	9.97	8.15	8.20	7.19
					Gasoline (gasoline)	52.37	45.66	50.08	44.55
Diesel oil	18.51	19.03	19.80	22.79
					Heavy oil	9.37	16.65	12.03	15.79
Coke	8.55	9.38	8.78	8.63
					Conversion/m%	72.13	64.31	68.17	61.41
Yield of light oil/m%	70.88	64.69	69.87	67.34
					Light harvesting + liquefied gas/m%	80.85	72.84	78.07	74.53
Coke/conversion ratio	0.12	0.14	0.13	0.14

As can be seen from Table 3, compared with comparative samples DBY-2 and DBY-4, the PBY-1 and PBY-6 molecular sieves prepared by the method have excellent heavy oil cracking activity after being subjected to hydrothermal aging treatment at 800 ℃ under 100% of water vapor for 17 hours, the conversion rates are respectively improved by 7.82 percent and 6.76 percent, the gasoline yield is respectively improved by nearly 6.71 percent and 5.53 percent, and the coke/conversion rate is reduced by 0.02 and 0.01, which shows that the rare earth Y-type molecular sieve obtained by pressure roasting treatment under the water vapor atmosphere has higher cracking activity stability and reduced coke selectivity.

Claims

1. The preparation method of the rare earth Y-type molecular sieve comprises the following steps: the method comprises the steps of carrying out hydrothermal roasting treatment on a rare earth NaY molecular sieve at 300-800 ℃ under the atmosphere environment of externally applying pressure and externally adding an aqueous solution containing an acidic substance or an alkaline substance, and recovering a product, wherein the atmosphere environment has an apparent pressure of 0.01-1 MPa and contains 1-100% of water vapor, the acidic substance comprises one or a mixture of more of ammonium chloride, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, hydrochloric acid, sulfuric acid and nitric acid, and the alkaline substance comprises one or a mixture of more of ammonia water, a buffer solution of ammonia water and ammonium chloride, sodium hydroxide, sodium carbonate and sodium bicarbonate.

2. The method according to claim 1, wherein the rare earth NaY molecular sieve is obtained by contacting NaY molecular sieve with rare earth salt solution or mixed solution of rare earth salt solution and ammonium salt, filtering, washing and drying.

3. The method of claim 2 wherein the rare earth salt solution comprises an aqueous chloride solution containing one or more of lanthanum, cerium, praseodymium, and neodymium ions.

4. The method according to claim 2, wherein the ammonium salt is selected from the group consisting of any one or more of ammonium chloride, ammonium nitrate, ammonium carbonate and ammonium bicarbonate.

5. The method according to claim 2, wherein the NaY molecular sieve is contacted with the rare earth salt solution or the mixed solution of the rare earth salt solution and the ammonium salt, and the NaY molecular sieve and the rare earth salt solution or the mixed solution of the ammonium salt and the rare earth salt solution are exchanged for at least 0.3 hour at a slurry pH = 3.0-5.0, a water-sieve weight ratio is 5-30, and an exchange temperature is room temperature-100 ℃.

6. The method according to claim 1, wherein the atmospheric environment has an apparent pressure of 0.1 to 0.8MPa and the hydrothermal calcination treatment temperature is 400 to 600 ℃.

7. The process according to claim 6, wherein the apparent pressure is 0.3 to 0.6 MPa.

8. The method of claim 1, wherein said atmosphere contains 30 to 100% water vapor.

9. The method of claim 8, wherein said atmosphere contains 60 to 100% water vapor.

10. A rare earth Y-type molecular sieve obtainable by the process of any one of claims 1 to 9.

11. The molecular sieve of claim 10, having at least two mesoporous pore size distributions at 2 to 3nm and 3 to 4nm, and a mesopore volume of greater than 0.03 cc/g.

12. The molecular sieve of claim 11, wherein said mesopore volume is from 0.031cc/g to 0.037 cc/g.

13. A molecular sieve according to claim 10, characterized in that the ratio of the intensity of the 2 θ =11.8 ± 0.1 ° peak, I1, to the intensity of the 2 θ =12.3 ± 0.1 ° peak, I2, in the X-ray diffraction pattern is 4.0 or more.

14. A molecular sieve according to claim 13 wherein the ratio of the intensity of the 2 θ =11.8 ± 0.1 ° peak, I1, to the intensity of the 2 θ =12.3 ± 0.1 ° peak, I2, in said X-ray diffraction pattern is from 4.5 to 6.0.

15. A molecular sieve according to claim 10 having a rare earth content of from 2 to 18% by weight, based on rare earth oxide, a unit cell constant of from 2.440 to 2.470nm and a crystallinity of from 30 to 60%.

16. A molecular sieve according to claim 15 wherein said rare earth is present in an amount of from 8 to 15 wt% based on rare earth oxide.