Ultra-stable rare earth Y-type molecular sieve and preparation method therefor

Patent metadata

Field	Value
Publication number	US-9789475-B2
Application number	US-201214365489-A
Country	US
Kind code	B2
Filing date	Apr 13, 2012
Priority date	Dec 15, 2011
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

The present invention provides an ultra-stable rare earth type Y molecular sieve and the preparation method thereof, which method is carried out by subjecting a NaY molecular sieve as the raw material to a rare earth exchange and a dispersing pre-exchange, then to an ultra-stabilization calcination treatment. The molecular sieve comprises 1 to 20% by weight of rare earth oxide, not more than 1.2% by weight of sodium oxide, has a crystallinity of 51 to 69%, and a lattice parameter of 2.451 nm to 2.469 nm. In contrast to the prior art, in the molecular sieve prepared by this method, rare earth ions are located in sodalite cages, which is demonstrated by the fact that no rare earth ion is lost during the reverse exchange process. Moreover, the molecular sieve prepared by such a method has a molecular particle size D(v,0.5) of not more than 3.0 μm and a D(v,0.9) of not more than 20 μm. Cracking catalysts using the molecular sieve as an active component is characterized by a high heavy-oil-conversion capacity and a high yield of valuable target products.

First claim

What is claimed is:

1. An ultra-stable rare earth type Y molecular sieve, wherein the ultra-stable rare earth type Y molecular sieve comprises 1% to 20% by weight of rare earth oxide and not more than 1.2% by weight of sodium oxide, and has a crystallinity of 51% to 69% and a lattice parameter of 2.449 nm to 2.469 nm;
wherein the ultra-stable rare earth type Y molecular sieve is prepared from a NaY molecular sieve as a raw material, the preparation process of the ultra-stable rare earth type Y molecular sieve includes subjecting the raw material to a rare earth exchange and a dispersing pre-exchange to give a molecular sieve slurry, subjecting the molecular sieve slurry to filtration, washing, and a first calcination to afford a “one-exchange one-calcination” rare earth sodium Y molecular sieve, and subjecting the “one-exchange one-calcination” rare earth sodium Y molecular sieve to an ammonium salt exchange for sodium reduction and a second calcination, so as to obtain the ultra-stable rare earth type Y molecular sieve, wherein the order of the rare earth exchange and the dispersing pre-exchange is not limited, and the rare earth exchange and the dispersing pre-exchange are consecutively conducted without a calcination process therebetween;
wherein the dispersing pre-exchange comprises adjusting a slurry of the molecular sieve to a solid content of 80 to 400 g/L and adding 0.2% to 7% by weight of a dispersing agent, wherein dispersing pre-exchange is carried out at an exchange temperature of 0 to 100° C. for 0.1 to 1.5 h; the dispersing agent in the dispersing pre-exchange process is selected from one or more of sesbania gum powder, boric acid, urea, ethanol, polyacrylamide, acetic acid, oxalic acid, adipic acid, formic acid, hydrochloric acid, nitric acid, citric acid, salicylic acid, tartaric acid, benzoic acid, and starch; and
wherein no ammonium salt is used in the rare earth exchange or the dispersing pre-exchange.

2. The ultra-stable rare earth type Y molecular sieve according to claim 1 , wherein the dispersing agent in the dispersing pre-exchange process is selected from two or more of sesbania gum powder, boric acid, urea, ethanol, polyacrylamide, acetic acid, oxalic acid, adipic acid, formic acid, hydrochloric acid, nitric acid, citric acid, salicylic acid, tartaric acid, benzoic acid, and starch.

3. The ultra-stable rare earth type Y molecular sieve according to claim 1 , wherein during the dispersing pre-exchange, the dispersing agent is added in an amount of from 0.2% to 5% by weight and the exchange temperature is 60 to 95° C.

4. A method of preparing an ultra-stable rare earth type Y molecular sieve comprising 1% to 20% by weight of rare earth oxide and not more than 1.2% by weight of sodium oxide, and has a crystallinity of 51% to 69% and a lattice parameter of 2.449 nm to 2.469 nm from a NaY molecular sieve as a raw material, the method comprising
subjecting the raw material to a rare earth exchange and a dispersing pre-exchange to give a molecular sieve slurry,
subjecting the molecular sieve slurry to filtration, washing, and a first calcination to afford a “one-exchange one-calcination” rare earth sodium Y molecular sieve, wherein the order of the rare earth exchange and the dispersing pre-exchange is not limited; and
subjecting the “one-exchange one-calcination” rare earth sodium Y molecular sieve to an ammonium salt exchange for sodium reduction and a second calcination, so as to obtain an ultra-stable rare earth type Y molecular sieve,
wherein the dispersing pre-exchange comprises adjusting a slurry of the molecular sieve to a solid content of 80 to 400 g/L and adding 0.2% to 7% by weight of a dispersing agent, wherein dispersing pre-exchange is carried out at an exchange temperature of 0 to 100° C. for 0.1 to 1.5 h; the dispersing agent in the dispersing pre-exchange process is selected from one or more of sesbania gum powder, boric acid, urea, ethanol, polyacrylamide, acetic acid, oxalic acid, adipic acid, formic acid, hydrochloric acid, nitric acid, citric acid, salicylic acid, tartaric acid, benzoic acid, and starch; and
wherein no ammonium salt is used in the rare earth exchange or the dispersing pre-exchange.

5. The method of preparing the ultra-stable rare earth type Y molecular sieve according to claim 4 , wherein the NaY molecular sieve has a silica-to-alumina ratio greater than 4.0, and a crystallinity greater than 70%.

6. The method of preparing the ultra-stable rare earth type Y molecular sieve according to claim 4 , wherein during the rare earth exchange, RE 2 O 3 /Y zeolite is in a mass ratio of from 0.005 to 0.25, the exchange temperature is 0 to 100° C., the exchange pH is 2.5 to 6.0, and the exchange time is 0.1 to 2 h.

7. The method of preparing the ultra-stable rare earth type Y molecular sieve according to claim 6 , wherein during the rare earth exchange, the mass ratio of RE 2 O 3 /Y zeolite is 0.01 to 0.20, the exchange temperature is 60 to 95° C., the exchange pH is 3.5 to 5.5, and the exchange time is 0.3 to 1.5 h.

8. The method of preparing the ultra-stable rare earth type Y molecular sieve according to claim 4 , wherein the first calcination is carried out at 350 to 700° C. under 0 to 100% water vapor for 0.3 to 3.5 h.

9. The method of preparing the ultra-stable rare earth type Y molecular sieve according to claim 4 , wherein the ammonium salt exchange and the second calcination of the “one-exchange one-calcination” ultra-stable rare earth sodium Y molecular sieve comprises:
adding the “one-exchange one-calcination” ultra-stable rare earth sodium Y molecular sieve into deionized water,
adjusting the solid content thereof to 100 to 400 g/L to give a mixture, wherein NH 4 + /Y zeolite is in a mass ratio of 0.02 to 0.40, and the pH is 2.5 to 5.0;
allowing the mixture to react at 60 to 95° C. for 0.3 to 1.5 h, followed by subjecting the molecular sieve slurry to filtration and washing to give a filter cake; and
calcinating the filter cake at 450 to 700° C. under 0 to 100% water vapor for 0.3 to 3.5 h.

10. The method of preparing the ultra-stable rare earth type Y molecular sieve according to claim 9 , wherein
the condition of the ammonium salt exchange of the “one-exchange one-calcination” ultra-stable rare earth sodium Y molecular sieve is as follows: the mass ratio of NH 4 + /Y zeolite is 0.02 to 0.30, and the pH is 3.0 to 4.5; and
the filter cake is calcinated at 450 to 700° C. under 0 to 100% water vapor for 0.5 to 2.5 h.

11. The method of preparing the ultra-stable rare earth type Y molecular sieve according to claim 4 , wherein the rare earth exchange and the dispersing pre-exchange comprise tank-type exchange, belt-type exchange and/or filter cake exchange.

12. The method of preparing the ultra-stable rare earth type Y molecular sieve according to claim 4 , wherein the rare earth exchange comprises, dividing a solution of a rare earth compound into multiple portions and using the portions to carry out tank-type exchange, belt-type exchange and/or filter cake exchange, provided that the total amount of the dispersing agent is not changed.

13. The method of preparing the ultra-stable rare earth type Y molecular sieve according to claim 4 , wherein the dispersing pre-exchange comprises, dividing the dispersing agent into multiple portions and using the portions to carry out tank-type exchange, belt-type exchange and/or filter cake exchange.

14. The method of preparing the ultra-stable rare earth type Y molecular sieve according to claim 4 , wherein when the rare earth exchange and the dispersing pre-exchange are multiple exchanges, these two types of exchange are carried out alternate

Assignees

• Gao Xionghou
• Zhang Haitao
• Tan Zhengguo
• Li Di
• Ji Dong
• Duan Hongchang
• Zhang Chenxi
• Petrochina Co Ltd

Inventors

• Gao Xionghou
• Zhang Haitao
• Tan Zhengguo
• Li Di
• Ji Dong
• Duan Hongchang
• Zhang Chenxi

Classifications

• C10G11/05

  Crystalline alumino-silicates, e.g. molecular sieves · CPC title

• B01J29/088 Primary

  Y-type faujasite · CPC title

• B01J35/023

  Operations & Transport · mapped topic

• B01J2229/186

  not in framework positions · CPC title

• B01J2229/40

  Special temperature treatment, i.e. other than just for template removal · CPC title