Alumina and alumina extrudates and process for preparation thereof

Patent metadata

Field	Value
Publication number	US-10576457-B2
Application number	US-201815918191-A
Country	US
Kind code	B2
Filing date	Mar 12, 2018
Priority date	Mar 14, 2017
Publication date	Mar 3, 2020
Grant date	Mar 3, 2020

Abstract

The present disclosure relates to an alumina having a surface area in the range of 330-400 m2/g, a pore volume in the range of 1.2-1.7 cc/g, and an average pore diameter in the range of 125-160 Å. The present disclosure also relates to alumina extrudates having a diameter in the range of 1 mm to 3 mm, a surface area in the range of 300-360 m2/g, a pore volume in the range of 0.8-1.3 cc/g and pore diameter in the range of 90-130 Å with a crushing strength in the range of 1-2.5 daN/mm. Further, the present disclosure relates to a process for the preparation of alumina and alumina extrudates. The alumina extrudates can be used as a support for catalyst preparation or as a catalyst or adsorbent in various processes. The process of the present disclosure enhances metal loading capacity, has better metal dispersion, and exhibit delay in deactivation of the catalyst due to mouth pore plugging.

First claim

The invention claimed is:

1. A process for preparing alumina having surface area in the range of 330-400 m 2 /g, pore volume in the range of 1.2-1.7 cc/g, and average pore diameter in the range of 125-167 Å, said process comprising the following steps:
a. mixing at least one alumina source in water to obtain an aqueous mixture;
b. mixing at least one templating agent in said aqueous mixture under stirring to obtain a gel;
c. adjusting pH of said gel in the range of 4-10 followed by maintaining said pH, for a time period in the range of 1 hour to 3 hours, to obtain a pH adjusted gel;
d. aging said pH adjusted gel at a temperature in the range of 60° C. to 120° C. to obtain a precipitate;
e. filtering said precipitate followed by washing with water, and drying to obtain a dried precipitate; and
f. calcining said dried precipitate to obtain alumina,
wherein the amount of said templating agent is in the range of 0.05 to 0.2 mole ratio of said alumina wherein said templating agent is at least one selected from the group consisting of cetyltrimethylammonium bromide (CTAB), tetraethylammonium bromide (TEABr), tetrapropylammonium bromide (TPABr), and tetrabutylammonium bromide (TBABr).

2. The process as claimed in claim 1 , wherein said alumina source is at least one selected from the group consisting of aluminium hydroxide, aluminium nitrate, aluminium sulphate, aluminium iso-butoxide, and aluminium iso-propoxide.

3. The process as claimed in claim 1 , wherein said pH of said gel is adjusted by adding at least one mineral acid selected from the group consisting of nitric acid, hydrochloric acid, and sulfuric acid; or ammonia.

4. The process as claimed in claim 1 , wherein the molar proportion of said alumina source:said templating agent:water is in the range of 1:0.05:20 to 1:0.05:60.

5. The process as claimed in claim 1 , wherein the process further comprises a process for preparing alumina extrudates wherein said-alumina extrudates have a surface area in the range of 300-360 m 2 /g, pore volume in the range of 0.8-1.3 cc/g, average pore diameter in the range of 90-130 Å and single grain crushing strength in the range of 1 daN/mm to 2.5 daN/mm, said process comprising:
i. mixing said dried precipitate obtained in step (e) or said alumina obtained in step (f) of claim 1 , with a binder solution to obtain a dough;
ii. extruding said dough to obtain extrudates; and
iii. drying said extrudates followed by calcination to obtain said alumina extrudates.

6. The process for preparing alumina extrudates as claimed in claim 5 , wherein said binder is at least one selected from the group consisting of polyvinyl alcohol, ethylene glycol and starch.

7. The process for preparing alumina extrudates as claimed in claim 5 , wherein said binder solution further comprises at least one carboxylic acid selected from the group consisting of acetic acid, oxalic acid, stearic acid, and citric acid.

8. The process for preparing alumina extrudates as claimed in claim 5 , wherein said extrudates are in a form selected from the group consisting of cylindrical, trilob, quadra lob, and star shaped.

Assignees

• Reliance Industries Ltd

Inventors

• Deshmukh Amit Arvind
• Deshmukh Sandip Sahebrao
• Salgaonkar Sanket Shamsunder
• Sethia Govind

Classifications

• B01J37/08

  Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• C01F7/025

  Granulation or agglomeration · CPC title

• B01J37/0207

  Pretreatment of the support · CPC title

• C01P2006/21

  Attrition-index or crushing strength of granulates · CPC title

• C01F7/36

  from organic aluminium salts · CPC title