CN1005385B

CN1005385B - Y-type molecular sieve cracking catalyst containing rare earth oxide

Info

Publication number: CN1005385B
Application number: CN86107531.5A
Authority: CN
Inventors: 舒兴田; 李才英; 何鸣元
Original assignee: Sinopec Research Institute of Petroleum Processing
Current assignee: Sinopec Research Institute of Petroleum Processing
Priority date: 1986-12-06
Filing date: 1986-12-06
Publication date: 1989-10-11
Also published as: CN86107531A

Abstract

一种含稀土Ｙ型分子筛的烃类裂化催化剂是以５～４０％，的含稀土氧化物的ＨＹ型分子筛为活性组分，辅以９５～６０％的以胶状Ａｌ（ＯＨ）₃为粘结剂的半合成载体构成。其分子筛中的稀土全部以ＲＥ₂Ｏ₃状态存在，可交换阳离子位置为Ｈ⁺或Ｎａ⁺占有。Ｃｕｋα激发时该分子筛的Ｘ光衍射谱图在２θ角为２７°以前和２９°以后均与常规ＨＹ型分子筛相同，但于２７～２９°位置上有一弥散的ＲＥ₂Ｏ₃特征峰。该催化剂有效地减少了氢转移反应，适用于裂化重油，特制是钠含量高的重油。A kind of hydrocarbon cracking catalyst containing rare earth Y-type molecular sieve is active component of 5-40% HY-type molecular sieve containing rare earth oxide, supplemented by 95-60% colloidal Al(OH) ₃ as viscous The semi-synthetic carrier composition of the binding agent. All the rare earths in the molecular sieve exist in RE ₂ O ₃ state, and the exchangeable cation positions are occupied by H ⁺ or Na ⁺ . When excited by Cukα, the X-ray diffraction pattern of the molecular sieve is the same as that of the conventional HY type molecular sieve before and after 2θ angle of 27°, but there is a diffuse RE ₂ O ₃ characteristic peak at the position of 27-29°. The catalyst effectively reduces the hydrogen transfer reaction and is suitable for cracking heavy oil, especially heavy oil with high sodium content.

Description

Y-type molecular sieve cracking catalyst containing rare earth oxide

The invention relates to a molecular sieve catalyst for hydrocarbon cracking and a preparation method thereof. In particular to a Y-type molecular sieve catalyst containing rare earth oxide and a preparation method thereof, which are suitable for cracking heavy oil, in particular heavy oil with high sodium content.

With the development of the oil refining industry towards the advanced processing direction, the cracking raw oil is heavier and heavier, and the cracking catalyst has the problems of reducing the coking rate and improving the heavy metal and sodium pollution resistance.

Of the reactions that occur during catalytic cracking, bimolecular hydrogen transfer reactions are critical to the coking rate. To reduce the coking rate, the hydrogen transfer reaction must be reduced. The existing widely-used rare earth-Y (REY) molecular sieve cracking catalyst has higher activity, but because RE ³⁺ is positioned at a cationic position, the dealumination reaction of a molecular sieve framework can be obviously inhibited in the thermal or hydrothermal aging process, and as a result, the concentration of acid centers in the molecular sieve is too high, and the ultra-stable-Y (USY) molecular sieve with a high framework SiO ₂/Al₂O₃ in the hydrogen transfer reaction （J·S·Magee et al.,Zeolite Chemistry and Catalysis,ACS Mono-geaph,171,P615,1976;J·S·Magee et al.,Preprints,ACS23,10571978）. in the catalysis process is accelerated, although the hydrogen transfer reaction can be effectively reduced, the cell shrinkage phenomenon can occur in the thermal or hydrothermal aging process, so that the activity of the catalyst is greatly reduced (Ussup 3,994,800).

Although the addition of RE (OH) ₃ to the support has been reported in the literature (Ussup 4,480,047, ussup 4,499,197, GB2,116,868) to improve the heavy metal contamination resistance of cracking catalysts, it has not been reported so far how to render them resistant to sodium contamination. In general, sodium in crude oil is difficult to completely remove even after deep desalting treatment, and in particular, organic sodium is more difficult to remove. These sodium are less likely to poison the acid sites of the catalyst and are more likely to destroy the molecular sieve structure on the catalyst. Thus, how to solve the sodium contamination resistance from the catalyst itself, in particular from the molecular sieve itself as an active component, is also a problem faced by the current cracking catalysts.

In view of the above-mentioned problems of the existing cracking catalysts, it is an object of the present invention to provide a molecular sieve cracking catalyst which combines high activity of REY type molecular sieve catalysts with excellent selectivity of USY type molecular sieve catalysts and which has sodium contamination resistance. The invention also provides a preparation method of the molecular sieve cracking catalyst and an active component molecular sieve thereof.

The molecular sieve cracking catalyst provided by the invention is formed by taking 5-40% of HY-type molecular sieve containing rare earth oxide as an active component and 95-60% of semisynthetic carrier taking colloidal Al (OH) ₃ as a binder. The rare earth in the active component HY type molecular sieve exists in a state of RE ₂O₃, and the exchangeable cation position is occupied by H ⁺ or Na ⁺. The X-ray powder diffraction pattern of the HY type molecular sieve containing RE ₂O₃ is similar to that of a conventional HY type molecular sieve, but the former has a characteristic peak of dispersed RE ₂O₃ at a position with an angle of 20 ℃ of 27-29 ℃, and the intensity of the characteristic peak depends on the content of rare earth.

The X-ray powder diffraction spectrum chart shown in fig. 1 shows the structural characteristics of the molecular sieve provided by the invention. In the figure, the diffraction pattern (1) is RE ₂O₃, (2) is the HY type molecular sieve containing RE ₂O₃ provided by the invention, and (3) is a conventional HY type molecular sieve.

Our experiments show that the activity of the catalyst can be brought to the level of REY-type molecular sieve catalysts on the basis of preserving the USY-type molecular sieve selectivity by using RE ₂O₃ or RE (OH) ₃ to adjust the cell shrinkage of the molecular sieve during thermal or hydrothermal aging. Our experiments also show that RE ₂O₃ or RE (OH) ₃ reacts readily with sodium, and the presence of RE ₂O₃ or RE (OH) ₃ in the molecular sieve greatly improves the resistance of the molecular sieve to sodium contamination.

The HY type molecular sieve containing RE ₂O₃ can be prepared by one of the following methods:

Dispersing RECl ₃ solution in NaY type molecular sieve alkaline colloid to be crystallized, adding a proper amount of NaOH to keep the total alkalinity of a colloid system unchanged, standing and crystallizing at 80-120 ℃ and preferably 95-100 ℃ for 20-24 hours after RE (OH) ₃ precipitate to be generated is uniformly dispersed in the colloid, and then filtering, washing, ammonium exchanging, roasting and the like.

Dispersing RECl ₃ solution in crystallized NaY type molecular sieve alkaline slurry, uniformly dispersing RE (OH) ₃ precipitate in the molecular sieve slurry, filtering, washing, ammonium exchanging, roasting and the like.

The RECl ₃ solution used in the preparation process can be mixed RECl ₃ solution with any composition, but is preferably a rare earth solution rich in La (La content is not less than 30%). The rare earth is used in an amount such that the molecular ratio of RE ₂O₃ to Al ₂O₃ in the molecular sieve is 0.11-1.50, preferably 0.25-0.55.

The ammonium exchange can be carried out by using (NH ₄）₂SO₄ solution, the exchange condition is that the weight ratio of (NH ₄）₂SO₄) to molecular sieve (burning group) is 0.5-2.0, preferably 0.8-1.2 (the concentration of NH ₄）₂SO₄ solution is 1-30%, preferably 5-15%, the exchange temperature is 35-150 ℃, preferably 50-90 ℃, the exchange time is 5-60 minutes, preferably 10-30 minutes, and the exchange times are 1-3.

The ammonium exchanged molecular sieve may be washed before calcination or after calcination, and may be washed with the support during catalyst preparation.

The roasting condition is 450-750 ℃, preferably 500-600 ℃ and 0.5-3 hours.

The molecular sieve after the primary ammonium exchange and roasting can be subjected to the secondary ammonium exchange and roasting.

The HY type molecular sieve containing RE ₂O₃ is dispersed in a semisynthetic carrier with colloidal Al (OH) ₃ as a binder according to the required proportion (for example, the molecular sieve is 5-40:95-60), and the HY type molecular sieve catalyst containing RE ₂O₃ can be prepared.

The catalyst prepared by adopting the HY type molecular sieve containing RE ₂O₃ as an active component can not only effectively reduce hydrogen transfer reaction, but also remarkably reduce cell shrinkage in the thermal or hydrothermal aging process. The cracking selectivity of the catalyst is close to that of a conventional USY type molecular sieve catalyst, and the activity and the hydrothermal stability of the catalyst are close to those of a conventional REY type molecular sieve catalyst. In addition, the catalyst has the performance of resisting sodium, vanadium and nickel pollution, and is simple and convenient to prepare. The catalyst is suitable for the catalytic cracking and hydrocracking of hydrocarbons including heavy oil, especially heavy oil with high sodium content.

The preparation method of the RE ₂O₃ -containing HY type molecular sieve is also suitable for introducing rare earth into A type or X type molecular sieves, mordenite and high-silicon zeolite (such as ZSM-5), and the rare earth in the corresponding product is also in the RE ₂O₃ state, so that the prepared catalyst has similar advantages as the RE ₂O₃ -containing HY type molecular sieve. For example, the pulse micro-reaction activity of the RE ₂O₃ -containing HZSM-5 molecular sieve (SiO ₂/Al₂O₃ =60) catalyst prepared by the method provided by the invention to the tetradecane is improved by 140-165% compared with the HZSM-5 molecular sieve catalyst after being treated by 800 ℃ and 100% water vapor for 4 hours.

The following examples will further illustrate the invention.

HY-type molecular sieves a, b and c containing RE ₂O₃ are prepared according to the molecular sieve preparation methods (1) and (2) (see Table 1).

Preparation of molecular sieve a:

(1) 210.7 g of a concentrated water glass solution (wherein SiO ₂28%,Na₂ O8.8%) was diluted with 150 g of deionized water to give a water glass solution (I);

(2) 17.2 g of the concentrated sodium silicate solution is reacted with 23.9 g of a dilute sodium metaaluminate solution (Na ₂O17.1%,Al₂O₃ 2.3.3% in the solution) and the reaction is aged at room temperature for 27 hours, 41.1 g of a directing agent (II) is obtained;

(3) Adding the solution (II) into the solution (I), dispersing uniformly, slowly adding 34.4 g of concentrated sodium metaaluminate solution (Na ₂O22.3%,Al₂O₃ 19.6.6%) under stirring, and continuing stirring for 15 minutes after the addition is finished to obtain alkaline colloid (III);

(4) A mixed solution of 39 g of AlCl ₃ solution (calculated as Al ₂O₃ content of 8.8%) and 44 ml of RECl ₃ solution (calculated as RE ₂O₃ content of 261.6 g/l, wherein La ₂O₃ is more than or equal to 30%) is added to (III) with stirring, and a proper amount of NaOH is added to make the total alkalinity of the colloidal system equal to (III), and the molecular ratio of RE ₂O₃/Al₂O₃ in the slurry is 0.33;

(5) After RE (OH) ₃ precipitate generated in the step (4) is uniformly dispersed in colloid, standing and crystallizing for 20 hours at 97+/-1 ℃, and filtering and washing the crystallized slurry to pH9-10;

(6) According to the dosage ratio of (NH ₄）₂SO₄: molecular sieve (burning group) to H ₂ O=1:1:20 (weight ratio), carrying out ammonium exchange at 90 ℃ for 0.5 hour, then filtering, and roasting the filter cake at 550 ℃ for 2 hours to obtain the HY type molecular sieve a containing RE ₂O₃.

Preparation of molecular sieve b:

100 g of NaY molecular sieve (the molecular composition of which is Na ₂O·Al₂O₃·5SiO₂·nH₂ O) slurry containing 70% of mother liquor, which is prepared by crystallization by a directing agent method, is added into 90 ml of RECl ₃ solution (the content of RE ₂O₃ is 261.6 g/L, wherein La ₂O₃ is more than or equal to 30%) under stirring, and the molecular ratio of RE ₂O₃/Al₂O₃ in the obtained mixed slurry is 0.33. After the RE (OH) ₃ precipitate generated is uniformly dispersed in molecular sieve slurry, filtering and washing to pH 9-10, then carrying out ammonium exchange and roasting according to the preparation step (6) of the molecular sieve a to obtain the HY-type molecular sieve b containing RE ₂O₃,

Preparation of molecular sieve c:

And carrying out secondary ammonium exchange and roasting on the molecular sieve b to obtain the HY-type molecular sieve c containing RE ₂O₃.

Analysis of molecular sieves a, b, and c by X-ray fluorescence (Japanese Condition 3014-X-ray fluorescence analyzer, tube pressure 1930V, tungsten target, EDDA crystal) showed that the molecular ratios of RE ₂O₃ and Al ₂O₃ in the product molecular sieves were all 0.33. Since the added rare earth can only exist in the form of RE (OH) ₃ before roasting under the pH condition for preparing the molecular sieve, the analysis result of the molecular ratio of RE ₂O₃/Al₂O₃ in the molecular sieve of the product is consistent with the molecular ratio at the time of feeding, which shows that the rare earth is totally precipitated in the molecular sieve in the form of RE (OH) ₃ in the preparation process, and RE (OH) ₃ is converted into RE ₂O₃ during roasting.

Analysis of molecular sieves a, b and c by a conventional X-ray powder diffraction method shows that the X-ray diffraction patterns of the molecular sieves a, b and c are similar to those of conventional HY-type molecular sieves, but have a characteristic peak of diffuse RE ₂O₃ at the position with the 2 theta angle of 27-29 degrees.

The molecular sieve single cell size data set forth in Table 1 was determined according to the 533 crystal plane position, as described in reference to ASTM-D3942-80. The measurement is cukα radiation, ni filtering, performed on a Japanese physics type D-max/IIIA X-ray diffractometer.

Examples 4 to 7

According to the preparation method of the molecular sieve b in examples 1-3, HY-type molecular sieve d, e, f, g (see Table 2) containing RE ₂O₃ is prepared according to different RE ₂O₃·Al₂O₃ (molecular ratio) feeding ratios.

Analysis of molecular sieves d, e, f, g by X-ray fluorescence (under the same conditions as in examples 1-3) showed that the molecular ratios of RE ₂O₃ and Al ₂O₃ in the product molecular sieves were 0.11, 0.22, 0.33, and 0.55, respectively. Since the added rare earth can only exist in the form of RE (OH) ₃ before roasting under the pH condition for preparing the molecular sieve, the analysis result of the molecular ratio of RE ₂O₃/Al₂O₃ in the molecular sieve of the product is consistent with the molecular ratio at the time of feeding, which shows that the rare earth is totally precipitated in the molecular sieve in the form of RE (OH) ₃ in the preparation process, and RE (OH) ₃ is converted into RE ₂O₃ during roasting.

Analysis of molecular sieve d, e, f, g by conventional X-ray powder diffraction method shows that the X-ray diffraction pattern of molecular sieve d, e, f, g is similar to that of conventional HY type molecular sieve, but has a characteristic peak of diffuse RE ₂O₃ at the position with the 2 theta angle of 27-29 degrees.

Example 8

The HY-type molecular sieve catalyst containing RE ₂O₃ is prepared according to the preparation method of the molecular sieve catalyst.

15 G (burning group) of each of the RE ₂O₃ -containing HY type molecular sieves a, b, C, d, e, f, g prepared in examples 1-3 and 4-7 are respectively soaked in a mortar to form uniform slurry, then the slurry is respectively added into 327 g of semisynthetic carrier (Al ₂O₃: carclazyte=25:75) with 26% of solid content and with acidified sub-Al (OH) ₃ gel as a binder, and after uniform stirring, the mixture is dried at 110 ℃ for 16 hours, thus obtaining the RE ₂O₃ -containing HY type molecular sieve catalyst, which is sequentially named as catalyst A, B, C, D, E, F, G.

For comparison, USY molecular sieves (wherein Al ₂O₃21%,Na₂ O <0.5%, single cell size 24.55

) And REY type molecular sieve (RE ₂O₃19%,SiO₂/Al₂O₃＝4.9,Na₂ O is less than 1.5% and single cell size is 24.71A) prepared by conventional two-step baking, and the catalyst is named as catalysts I and J.

Example 9

RE (OH) ₃ and/or RE ₂O₃ have the property of reducing molecular sieve unit cell shrinkage in the catalyst.

After the catalyst A, B, C, I is treated by water vapor with the concentration of 100 percent at 800 ℃ for 4 hours, the cell shrinkage degree is obviously different, the cell shrinkage phenomenon of the HY type molecular sieve containing RE ₂ O is obviously reduced compared with that of the conventional USY type molecular sieve, and the data are shown in Table 3.

Example 10

The HY type molecular sieve catalyst containing RE ₂O₃ can effectively reduce hydrogen transfer reaction, and has the characteristics of high yield of C ⁼ ₃、C⁼ ₄ gasoline and low coking rate.

The catalysts A, B, C, J after 4 hours of treatment with 800 ℃ and 100% steam were each evaluated for heavy oil micro-activity on a small fixed bed. The evaluation conditions are that the reactants are 300-500 ℃ victory wax oil (performance parameters are shown in table 4), the reaction temperature is 482 ℃, the catalyst-oil ratio is 3.0, the weight airspeed is ^-1 when 8, and the catalyst device is 27 g (20-40 meshes). The evaluation results are shown in Table 5.

Example 11

The activity of the HY type molecular sieve catalyst containing RE ₂O₃, which is prepared by different methods and has different fresh molecular sieve single crystal cell sizes, is similar to that of the conventional REY type molecular sieve catalyst and superior to that of the conventional USY type molecular sieve catalyst.

The activity of the catalyst A, B, C, I, J treated with 800 ℃ and 100% steam for 4 hours was evaluated on the light oil micro-reactor and the pulse micro-reactor, respectively. The evaluation condition of the light oil micro-activity is that the reactant is 200-300 ℃ distillate light diesel oil, the reaction temperature is 460 ℃, the catalyst-oil ratio is 3.0, and the weight airspeed is 16 hours ^-1. The catalyst loading is 5g (20-40 mesh). The evaluation condition of the pulse micro-activity is that the reactant is n-tetradecane, the sample injection amount is 0.3 microliter, the reaction temperature is 460 ℃, and the catalyst device is 0.1 gram (20-40 meshes). The evaluation results are shown in Table 6.

Example 12

When the RE ₂O₃ content in the catalyst is above 2.0%, the activity of the HY type molecular sieve catalyst containing RE ₂O₃ reaches the level of the conventional REY type molecular sieve catalyst, and the catalyst is superior to the conventional USY type molecular sieve catalyst.

The activity of the catalysts D, E, F, G, I, J after treatment with 800℃and 100% steam for 4 hours was evaluated on the pulse microreaction under the same conditions as in example 11, and the evaluation results are shown in Table 7.

Example 13

The activity stability of the HY type molecular sieve catalyst containing RE ₂O₃ is close to that of the conventional REY type molecular sieve catalyst and is superior to that of the conventional USY type molecular sieve catalyst.

The activity of the catalysts A, B, I, J treated with 800% water vapor, 100% water vapor for 4 hours, 8 hours, 12 hours and 14.5 hours was evaluated on a pulse microreaction under the same conditions as in example 11, and the evaluation results are shown in FIG. 2. FIG. 2 is a graph comparing the activity stability of several different catalysts, wherein curves (1) and (3) show the activity decrease trend of the conventional REY-type molecular sieve catalyst J and the conventional USY-type molecular sieve catalyst I, respectively, and curve (2) shows the activity decrease trend of the HY-type molecular sieve catalyst A, B containing RE ₂O₃.

From the different magnitudes of the activity decrease of each catalyst in fig. 2, it can be seen that the activity stability of the HY-type molecular sieve catalyst containing RE ₂O₃ provided by the present invention is close to that of the conventional REY-type molecular sieve catalyst.

Example 14

The HY type molecular sieve catalyst containing RE ₂O₃ has the characteristic of resisting sodium pollution.

The activity of the HY type molecular sieve catalyst C containing RE ₂O₃ and the conventional USY type molecular sieve catalyst I containing RE ₂O₃ with the same sodium content (which is converted to Na ₂ O0.06%) is evaluated on the pulse micro-inversion after the catalyst samples before and after sodium pollution are treated for 4 hours at 800 ℃ and 100% water vapor by respectively increasing the sodium content (which is converted to Na ₂ O content) by 0.5%, 1.0% and 1.5% on the original basis by an immersion method, and the evaluation conditions are the same as those of example 11, and the evaluation results are shown in figure 3. FIG. 3 is a graph comparing sodium contamination resistance of different catalysts, wherein curves (1) and (2) represent percent sodium content and catalyst activity retention on an HY type molecular sieve catalyst C containing RE ₂O₃ and a conventional USY type molecular sieve catalyst I, respectively.

(Cracking Activity after catalyst contamination with sodium/cracking Activity before catalyst contamination with sodium. Times.100%).

As can be seen from the graph 3, the RE ₂O₃ -containing HY type molecular sieve catalyst provided by the invention has better anti-sodium pollution performance than the conventional USY type molecular sieve catalyst, and when the pollution amount of sodium on the catalyst reaches 1.5% Na ₂ O, the activity of the catalyst can still be kept at 50%, while the activity of the catalyst only is kept at 25%.

The sodium impregnation method comprises grinding the catalyst sample into powder (150 meshes), roasting at 500 ℃ for 2 hours, fully mixing with NaCl aqueous solution with the weight of 1/2 of the sample, and drying at 120 ℃ to obtain the sodium-polluted catalyst sample.

Example 15

The anti-vanadium pollution performance of the HY type molecular sieve catalyst containing RE ₂O₃ is superior to that of the conventional USY type molecular sieve catalyst.

And (3) fully mixing the HY type molecular sieve catalyst C containing RE ₂O₃ and the conventional USY type molecular sieve catalyst I with calculated V ₂O₅ powder in a mortar, grinding, tabletting, forming, crushing, and sieving with 20-40 meshes. The samples C, I of the catalysts thus obtained, which had vanadium contents of 5000ppm, 10000ppm and no vanadium, were treated with 800℃and 100% steam for 4 hours, and were subjected to pulse microreaction evaluation and determination of the relative crystallinity retention, respectively. The pulse micro-inverse evaluation conditions were as in example 11 and the evaluation results were expressed as percent active retention (meaning as in example 14). The relative crystallinity retention is expressed as the ratio of the intensities of the X-diffraction peaks at the 2θ=23.65° positions before and after the hydrothermal treatment of the catalyst sample. The results are shown in Table 8.

Claims

1. A rare earth-containing Y-type molecular sieve cracking catalyst is characterized in that:

(a) The catalyst is formed by taking 5-40% of HY type molecular sieve containing rare earth oxide as an active component and 95-60% of semisynthetic carrier taking colloidal AL (OH) ₃ as a binder;

(b) The rare earth in the molecular sieve exists in a RE ₂O₃ state, the exchangeable cation position is occupied by H ⁺ or Na ⁺, the X-ray powder diffraction pattern of the molecular sieve is similar to that of a conventional HY-type molecular sieve, but a diffuse RE ₂O₃ characteristic peak is arranged at the position of 27-29 degrees [ in (2) in figure 1 ].

(C) The HY-type molecular sieve containing rare earth oxide can be prepared by the following steps:

(1) Dispersing the mixed RECl ₃ solution with any composition in NaY molecular sieve alkaline colloid to be crystallized, and adding a proper amount of NaOH to keep the total alkalinity of a colloid system unchanged, wherein the rare earth dosage is such that RE ₂O₃/Al₂O₃ (molecular ratio) contained in the molecular sieve is 0.11-1.50;

(2) After the RE (OH) ₃ precipitate generated is uniformly dispersed in the colloid, standing and crystallizing for 20-24 hours at 80-120 ℃, filtering and washing;

(3) Ammonium exchange is carried out by using 1-30% (NH ₄）₂SO₄ solution) (NH ₄）₂SO₄: molecular sieve (burning group) =0.5-2.0 (weight ratio), exchange is carried out for 1-3 times at 35-150 ℃ and each exchange is carried out for 5-60 minutes;

(4) Roasting for 0.5-3 hours at 450-750 ℃;

The molecular sieve after primary ammonium exchange and roasting can be subjected to secondary ammonium exchange and roasting;

(d) The HY-type molecular sieve containing rare earth oxide can also be prepared by the following steps:

(1) Dispersing the mixed RECl ₃ solution with any composition into crystallized NaY type molecular sieve alkaline slurry, wherein the rare earth consumption is such that RE ₂O₃/Al₂O₃ (molecular ratio) contained in the molecular sieve is 0.11-1.50;

(2) Uniformly dispersing the RE (OH) ₃ precipitate in molecular sieve slurry, filtering, and washing;

(3) Performing ammonium exchange with 1-30% (NH ₄）₂SO₄ solution, (NH ₄）₂SO₄: molecular sieve (burning group) =0.5-2.0 (weight ratio)), exchanging for 1-3 times at 35-150 ℃ for 5-60 minutes each time;

(4) Roasting for 0.5-3 hours at 450-750 ℃;

2. The catalyst according to claim 1, wherein the mixed RECl ₃ solution in (c) (1) and (d) (1) is a La-rich rare earth solution having a La content of not less than 30%, and the rare earth is used in such an amount that RE ₂O₃/Al₂O₃ (molecular ratio) contained in the molecular sieve is 0.25 to 0.55.

3. The catalyst according to claim 1, wherein the crystallization temperature in (C) (2) is 95 to 100 ℃.

4. The catalyst according to claim 1, wherein the ammonium exchange conditions in (C) (3) and (d) (3) are 5 to 15% (NH ₄）₂SO₄ solution, (NH ₄）₂SO₄ molecular sieve (glowing group) =0.8 to 1.2 (weight ratio)) at 50 to 90 ℃ for 10 to 30 minutes each time.

5. The catalyst according to claim 1, wherein the calcination temperature in (C) (4), (d) (4) is 500 to 600 ℃.

6. The molecular sieve catalyst of claim 1 for the catalytic cracking, hydrocracking of heavy oils, particularly heavy oils with high sodium content.