Sasol North America, Inc.

Daniel P Szura

Donald L Wharry

Mary J Brown

Joy L Murray

J Barry Winder

Richard C Howe

John R Schell

Wayne L Sorensen

Frank Gates

Wayne L Sorenson

Barry J Winder

A unified process which couples a unique in situ catalyst regeneration process with a continuous reactive distillation under pressure for the alkylation of light aromatic hydrocarbons such as benzene with C&#x2013;Colefins using a solid acid alkylation catalyst supported in the reflux zone of a distillation column. Periodic regeneration of the catalyst is carried out with a countercurrent injection of a C&#x2013;Cparaffin below the benzene rectification zone at the top of the column, but above the catalyst zone while the aromatic hydrocarbon reaction feedstock is injected continuously at a point above a rectification zone at the base of the column where the aromatic compound is separated from the paraffin and by-products washed from the catalyst. The use of the C&#x2013;Cparaffin with the aromatic at a mole fraction in the range of 40 to 90% enables a regeneration temperature of about 175&#x2013;250&#xb0; C. to be achieved and maintained by adjusting the column pressure and aromatic reflux rate. Significantly lower pressures, on the order of 125 to 370 psig, are required to achieve regeneration temperature than would be otherwise required with the use only of the aromatic hydrocarbon to dilute and wash the by-products from the catalyst surfaces.

Reactive distillation alkylation process including in situ catalyst regeneration

A unified process for reactive distillation under pressure for the alkylation of light aromatic hydrocarbons such as benzene and cumene with straight chain C -C olefins using a solid acid alkylation catalyst supported in the reflux zone of the distillation column. The process is continuous, using a reactive distillation configuration such that at least a portion of the olefin is injected below the benzene rectification zone at the top of the column. The aromatic hydrocarbon is injected continuously at a low rate above the rectification zone at the base of the column and above the reboiler. The alkylation reaction takes place primarily in the liquid phase on the solid acid catalyst and is characterized in that the molar ratio of aromatic hydrocarbon to olefin in the liquid phase may be adjusted. The molar ratio is adjustable up to about 100/1, through adjustment of the internal column operating pressure, the benzene reflux rate, the amount of benzene removed from the reflux condenser to storage or from the reboiler with the distillation column operated at or near total aromatic hydrocarbon reflux. The unexpectedly high liquid phase aromatic hydrocarbon to olefin molar ratios achieved in the reactive distillation column increases the selectivity to mono-alkylated aromatics and helps stabilize catalyst lifetime.

Reactive distillation process for the alkylation of aromatic hydrocarbons

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Georgetown, TX, United States of America

Daniel P Szura