Magnesium modified ultra-stable rare earth Y-type molecular sieve and preparation method therefor

Patent metadata

Field	Value
Publication number	US-9840422-B2
Application number	US-201214365432-A
Country	US
Kind code	B2
Filing date	Apr 13, 2012
Priority date	Dec 15, 2011
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

The present invention provides a magnesium-modified 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, and finally to a magnesium modification. The molecular sieve comprises 0.2 to 5% by weight of magnesium oxide, 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 46 to 63%, and a lattice parameter of 2.454 nm to 2.471 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. Such a molecular sieve has both high stability and high selectivity for the target product, while 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. A magnesium-modified ultra-stable rare earth type Y molecular sieve comprising, 0.2% to 5% by weight of magnesium oxide, 1% to 20% by weight of rare earth oxide, and not more than 1.2% by weight of sodium oxide, and having a crystallinity of 46% to 63%, and a lattice parameter of 2.454 nm to 2.471 nm;
wherein the magnesium-modified molecular sieve is prepared by a process comprising
treating a NaY molecular sieve used as a raw material to a rare earth exchange, a dispersing pre-exchange, and a first calcination to obtain 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, a magnesium salt exchange modification, and a second calcination to produce the magnesium-modified ultra-stable rare earth type Y molecular sieve,
wherein the magnesium salt exchange modification is carried out after the rare earth exchange and the dispersing pre-exchange, 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 concentration of a molecular sieve slurry concentration to a solid content of 80 to 400 g/L and adding 0.2% to 7% by weight of a dispersing agent at an exchange temperature of 0 to 100° C. for 0.1 to 1.5 h; wherein the dispersing agent in the dispersing pre-exchange 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 magnesium-modified ultra-stable rare earth type Y molecular sieve according to claim 1 , wherein the rare earth exchange comprises,
adjusting the concentration of the molecular sieve slurry to a solid content of 80 to 400 g/L,
adding a rare earth compound, wherein a rare earth oxide equivalent, RE 2 O 3 , of the rare earth compound and a NaY-molecular sieve are in a mass ratio of 0.005 to 0.25,
an exchange temperature is 0 to 100° C., an exchange pH is 2.5 to 6.0, and an exchange time is 0.1 to 2 h.

3. The magnesium-modified ultra-stable rare earth type Y molecular sieve according to claim 1 , wherein the magnesium salt exchange modification comprises,
adjusting the molecular sieve slurry's concentration to a solid content of 80 to 400 g/L,
adding 0.2% to 8% by weight of a magnesium salt for exchange modification,
an exchange temperature is 0 to 100° C., and an exchange time is 0.1 to 1.5.

4. The magnesium-modified ultra-stable rare earth type Y molecular sieve according to claim 2 , wherein the rare earth compound is a rare earth chloride, a rare earth nitrate or a rare earth sulfate.

5. The magnesium-modified ultra-stable rare earth type Y molecular sieve according to claim 2 , wherein the rare earth compound is a lanthanum-rich rare earth, a cerium-rich rare earth, a pure lanthanum rare earth, or a pure cerium rare earth.

6. The magnesium-modified ultra-stable rare earth type Y molecular sieve according to claim 3 , wherein the magnesium salt is selected from one or more of magnesium chloride, magnesium nitrate, and magnesium sulfate.

7. A method of preparing a magnesium-modified ultra-stable rare earth type Y molecular sieve using a NaY molecular sieve as a raw material, wherein the magnesium-modified ultra-stable rare earth type Y molecular sieve comprises 0.2% to 5% by weight of magnesium oxide, 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 46% to 63%, and a lattice parameter of 2.454 nm to 2.471 nm, the method comprising
treating the NaY molecular sieve to a rare earth exchange, a dispersing pre-exchange, 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, a magnesium salt exchange modification, and a second calcination to produce the magnesium-modified ultra-stable rare earth type Y molecular sieve,
wherein the magnesium salt exchange modification is carried out after the rare earth exchange and the dispersing pre-exchange, 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 concentration of a molecular sieve slurry concentration to a solid content of 80 to 400 g/L and adding 0.2% to 7% by weight of a dispersing agent at an exchange temperature of 0 to 100° C. for 0.1 to 1.5 h; wherein the dispersing agent in the dispersing pre-exchange 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;
wherein no ammonium salt is used in the rare earth exchange or the dispersing pre-exchange; and
wherein the order of the magnesium salt exchange modification and the ammonium salt exchange is not limited, the second calcination is carried out after the ammonium salt exchange for sodium reduction, and the magnesium salt exchange modification is conducted before, after, or both before and after the second calcination.

8. The preparation method according to claim 7 , comprising
subjecting the “one-exchange one-calcination” rare earth sodium Y molecular sieve to an ammonium salt exchange for sodium reduction and a second calcination, to produce a “two-exchange two-calcination” REUSY molecular sieve,
subjecting the “two-exchange two-calcination” REUSY molecular sieve to a magnesium salt exchange modification to produce the magnesium-modified ultra-stable rare earth type Y molecular sieve.

9. The preparation method according to claim 8 , further comprising
subjecting the “one-exchange one-calcination” rare earth sodium Y molecular sieve to a magnesium salt exchange modification before the second calcination.

10. The preparation method according to claim 7 , wherein the ammonium salt exchange for sodium reduction 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, wherein NH 4 + and the NaY molecular sieve are in a mass ratio of 0.02 to 0.40, and the ammonium salt exchange is carried out at a pH of 2.5 to 5.0, a temperature of 60 to 95° C. for 0.3 to 1.5 h; and
the second calcination is carried out under 0 to 100% water vapor at 350 to 700° C. for 0.3 to 3.5 h.

11. The preparation method according to claim 7 , wherein the “one-exchange one-calcination” ultra-stable rare earth sodium Y molecular sieve is produced by a process comprising
treating the NaY molecular sieve to a rare earth exchange followed by filtering to obtain a filter cake;
mixing the filter cake with a dispersing agent for a dispersing pre-exchange reaction, and
calcinating the filter cake.

12. The preparation method according to claim 7 , wherein the “one-exchange one-calcination” ultra-stable rare earth sodium Y molecular sieve is produced by a process comprising,
treating the NaY molecular sieve to a dispersing

Assignees

• Gao Xionghou
• Zhang Haitao
• Duan Hongchang
• Liu Chaowei
• Li Di
• Li Xueli
• Tan Zhengguo
• Zheng Yunfeng
• Huang Xiaoliang
• Cai Jinjun
• Zhang Chenxi
• Petrochina Co Ltd

Inventors

• Gao Xionghou
• Zhang Haitao
• Duan Hongchang
• Liu Chaowei
• Li Di
• Li Xueli
• Tan Zhengguo
• Zheng Yunfeng
• Huang Xiaoliang
• Cai Jinjun
• Zhang Chenxi

Classifications

• B01J29/088

  Y-type faujasite · CPC title

• B01J29/084

  Y-type faujasite · CPC title

• B01J29/80

  Mixtures of different zeolites · CPC title

• B01J35/109

  Operations & Transport · mapped topic

• B01J35/10

  Operations & Transport · mapped topic