US 2006/0149105 A1 · Low space-velocity transalkylation process for ethylbenzene

Abstract

The use of a low space-velocity reactor containing transalkylation catalysts to react heavy aromatic compounds of carbon number nine (and heavier carbon numbers) with benzene to form carbon number eight aromatics is disclosed. Conditions of low space-velocity promote approach to equilibrium at temperatures favoring carbon number eight aromatics. The catalyst system preserves ethyl-group species on the heavier aromatics that would otherwise be de-ethylated over most gas-phase transalkylation catalysts to form undesired ethane gas with benzene or toluene. The catalyst system also promotes methyl-group species transalkylation at selected conditions. Thus, by using a transalkylation step to save ethylbenzene, a greater yield of para-xylene or other carbon number eight aromatics may be achieved within an integrated aromatics complex.

Claims20

Dependent claims

A process for transalkylation of a benzene stream with C9+ alkylaromatics comprising contacting the stream within a low space-velocity reactor containing a transalkylation catalyst under at least partial liquid-phase transalkylation conditions to produce a product stream comprising ethylbenzene and at least 1 wt-% xylenes, the transalkylation conditions comprising a molar ratio of benzene to C9+ alkylaromatics from about 0.1 to about 10, a temperature less than about 300° C. and a space-velocity ranging from about 0.1 to about 0.3 hr−1 and wherein the C9+ alkylaromatics contain at least one component selected from the group consisting of alkylaromatic hydrocarbons of the formula C6H(6-n)Rn, where n is an integer from 1 to 5 and each R is independently selected from the group consisting of CH3, C3H7, and C4H9.

A process for conversion of aromatic hydrocarbons into para-xylene using a low space-velocity reactor integrated into an aromatics complex comprising:

a) providing a stream containing benzene and C9+ alkylaromatics, wherein the molar ratio of benzene to C9+ alkylaromatic is from about 0.1 to about 10 and wherein the C9+ alkylaromatics contain at least one component selected from the group consisting of alkylaromatic hydrocarbons of the formula C6H(6-n)Rn, where n is an integer from 1 to 5 and each R is independently selected from the group consisting of CH3, C3H7, and C4H9;
b) passing the stream of step (a) to an at least partial liquid-phase transalkylation unit, wherein the stream is contacted under transalkylation conditions including a space velocity from about 0.1 to about 0.3 hr−1, within a low space-velocity reactor containing transalkylation catalyst comprising a zeolitic aluminosilicate component selected from the group consisting of MTW, MFI, type Y, beta, and mordenite, and an inorganic oxide binder component, to produce a transalkylation product stream comprising ethylbenzene and at least 4 wt-% xylene calculated on a net effluent basis;
c) separating the product streams of step (b) in a fractionation zone comprising at least one column to produce a fractionated-benzene stream, and a xylene-plus stream;
d) separating the xylene-plus stream in a xylene column to produce a xylene enriched stream and a C9+ alkylaromatic-enriched stream;
e) passing the xylene enriched stream to a para-xylene production unit, wherein para-xylene is recovered as a product.

2 more elements

Dependencies are inferred from the claim text.

Low space-velocity transalkylation process for ethylbenzene

Life of this patent

Low space-velocity transalkylation process for ethylbenzene

Life of this patent

Abstract

Claims20