Patent ID: 6417420
Filing Date: 2002-07-09
Classification: B01D,C07C

Abstract:
A process for producing a product aromatic compound, the process comprising:a) dehydrogenating a feed stream comprising a C6-C22 paraffin in a dehydrogenetion zone and recovering therefrom a dehydrogenated product stream comprising a monoolefin and aromatic byproducts; b) selectively removing at least a portion of the aromatics byproducts from the dehydrogenated product stream by at least intermittently passing at least a portion of the dehydrogenated product stream to an on-strewn aromatic byproducts removal zone containing sorbent at conditions effective to selectively sorb the aromatic byproducts on the sorbent and to produce a sorption effluent stream comprising the monoolefin; c) passing at least a portion of the sorption effluent stream to a selective alkylation zone and selectively alkylating a feed aromatic compound by reacting the feed aromatic compound and the monoolefin in the selective alkylation zone to form a product aromatic compound; d) recovering from the selective alkylation zone an alkylated product stream comprising the product aromatic compound; e) at least intermittently passing a purge stream comprising a purge component to an off-stream purge aromatic byproducts removal zone containing sorbent, wherein the sorbent in the off-stream purge aromatic byproducts removal zone is contained in a sorbent bed having a void volume and wherein the void volume contains the C6-C22 paraffin or the monoolefin, to displace the C6-C22 paraffin or the monoolefin from the void volume of the sorbent bed in the off-stream purge aromatic byproducts removal zone, and producing a purging effluent stream comprising the C4-C6 paraffin and at least one of the C6-C22 paraffin and the monoolefin; f) at least intermittently passing a desorbent stream comprising a desortion component to an off-stream desorption aromatic byproducts removal zone containing sorbent, wherein the sorbent in the off-stream desorption aromatic byproducts removal zone contains sorbed aromatic byproducts, to desorb aromatic byproducts from the sorbent in the off-stream desorption aromatic byproducts removal zone, and producing a desorption effluent stream comprising the desorption component and the aromatic byproducts; g) at least intermittently passing at least a portion of the desorption effluent strewn to a first lateral section of an intermediate portion of a distillation column at distillation conditions, wherein the first lateral section is separated from a second lateral section of the intermediate portion of the distillation column by a vertically oriented baffle extending upward from a lower portion of the distillation column to an upper portion of the distillation column; h) at least intermittently passing at least a portion of the purging effluent stream to the upper portion of the distillation column; i) separating the compounds entering the distillation column to provide an overhead stream comprising the purge component, a sidedraw stream comprising the desorption component and a bottom stream comprising the aromatic byproducts; and j) periodically shifting the functions of the on-stream aromatic byproducts removal zone, the off-stream purge aromatic byproducts removal zone, and the off-stream desorption aromatic byproducts removal zone by operating the on-stream aromatic byproducts removal zone to function as the off-stream purge aromatic byproducts removal zone, operating the off-stream purge aromatic byproducts removal zone to function as the off-stream desorption aromatic byproducts removal zone, and operating the off-stream desorption aromatic byproducts removal zone to function as the on-stream aromatic byproducts removal zone.