Fixed-bed alkyl-aromatic conversion process

Patent metadata

Field	Value
Publication number	US-10173204-B2
Application number	US-201815975114-A
Country	US
Kind code	B2
Filing date	May 9, 2018
Priority date	Sep 20, 2016
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A method of preparing a metal-doped zeolite catalyst with a modified topology (e.g. a pillared zeolite or a delaminated zeolite), and a method of using thereof in a process for converting an alkyl-aromatic hydrocarbon stream to BTX (benzene/toluene/xylene), wherein an enhanced pore topology in the metal-doped zeolite catalyst determines a selectivity to transalkylation of trimethylbenzene to xylene, which in turn leads to a higher xylene yield. Various embodiments of the method of preparing the metal-doped zeolite catalyst, and the process for converting the alkyl-aromatic hydrocarbon stream to BTX are also provided.

First claim

The invention claimed is:

1. A process for converting an alkyl-aromatic hydrocarbon stream to a BTX-rich stream, comprising:
contacting the alkyl-aromatic hydrocarbon stream with a zeolite catalyst in the presence of hydrogen gas at a temperature in a range of 200-500° C. and at a pressure in a range of 1-3 MPa to form a product stream, wherein a molar ratio of the hydrogen gas to hydrocarbon compounds in the alkyl-aromatic hydrocarbon stream is in the range of 1:1-6:1, and wherein the zeolite catalyst comprises:
a pillared MWW zeolite, and
at least two metals selected from the group consisting of Pt, Re, Mo, and Ni,
wherein the zeolite catalyst comprises micro-pores having a specific pore volume in the range of 0.05-0.1 cm 3 /g, and meso-pores having a specific pore volume in the range of 0.3-0.5 cm 3 /g; and
wherein the contacting is carried out in a fixed-bed reactor and prior to the contacting the zeolite catalyst is placed in the fixed bed reactor, oxidized with an oxygen-containing gas and then reduced with hydrogen-containing gas, and
separating C 5− and C 9+ hydrocarbon compounds from the product stream to form the BTX-rich stream.

2. The process of claim 1 ,
wherein the zeolite catalyst is reduced with the hydrogen-containing gas in a temperature range of 250-450° C.

3. The process of claim 1 , wherein at least 50% by weight of the BTX-rich stream is xylene and the process further comprises separating xylene from the BTX-rich stream.

4. The process of claim 1 , wherein the alkyl-aromatic hydrocarbon stream comprises C 9+ alkyl-aromatic hydrocarbon compounds.

5. The process of claim 1 , wherein the alkyl-aromatic hydrocarbon stream has a space velocity in the range of 1-5 h −1 .

6. The process of claim 1 , wherein the alkyl-aromatic hydrocarbon stream comprises toluene and one or more of methylethylbenzene, trimethylbenzene, dimethylethylbenzene, and tetramethylbenzene, and the process further comprises reducing a toluene content of the alkyl-aromatic hydrocarbon stream in a separation unit prior to the contacting.

7. The process of claim 6 , wherein the alkyl-aromatic hydrocarbon stream has an average methyl-to-benzene molar ratio in the range of 2-2.5 prior to the contacting.

8. The process of claim 1 , wherein the zeolite catalyst comprises 0.1-1 wt % Pt and 0.1-1 wt % Re.

9. The process of claim 1 , wherein the pillared MWW zeolite comprises silica pillars.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Al-Khattaf Sulaiman Saleh
• Ali Syed Ahmed
• Aitani Abdullah Mohammed

Classifications

• B01J29/7876 Primary

  MWW-type, e.g. MCM-22, ERB-1, ITQ-1, PSH-3 or SSZ-25 · CPC title

• C07C6/06

  at a cyclic carbon-to-carbon double bond · CPC title

• C07C2529/78

  containing arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium · CPC title

• B01J29/78

  containing arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium · CPC title

• C07C2529/74

  Noble metals · CPC title