Patent ID: 6395950
Filing Date: 2002-05-28
Classification: B01D,C07C

Abstract:
An isomerization process having an adsorptive separation zone and a dividing wall fractionation zone, said process comprising:contacting, in an isomerization zone, a feed stream containing at least normal pentane and normal hexane with an isomerization catalyst under isomerization conditions to convert at least a portion of the normal pentane and normal hexane into isomerized products and form an isomerization zone effluent containing normal pentane, normal hexane and isomerized products; passing the isomerization zone effluent to an adsorptive separation zone comprising at least one bed of a selective adsorbent maintained at adsorption conditions under which the normal pentane and normal hexane are selectively retained on a quantity of the selective adsorbent, thus forming an isomerized product stream comprising at least the isomerized products; desorbing the normal pentane and normal hexane under desorption conditions to yield a normal alkane stream comprising at least normal pentane and normal hexane; passing the isomerized product stream into a dividing wall fractionation column operated at fractionation conditions and divided into at least a first and a second parallel fractionation zone by a dividing wall, with the first and the second fractionation zones each having an upper and a lower end located within the fractionation column, with the first and second fractionation zones being in open communication at their upper ends with an undivided upper section of the fractionation column and in open communication at their lower ends with an undivided lower section of the fractionation column, and with the isomerized product stream entering the column at an intermediate point of the first fractionation zone; removing a low-octane stream comprising 2-methylpentane and 3-methylpentane from an intermediate point of the second fractionation zone of the dividing wall fractionation column; removing a first high-octane stream from a first end of the dividing wall fractionation column, and removing a second high-octane stream from a second end of the dividing wall fractionation column.