GB904677A - Improvements in and relating to the removal of homologous hydrocarbons from mixturescontaining them - Google Patents

Abstract

The separation and recovery of different fractions of a homologous series of hydrocarbons from a mixture containing them is effected by passing the mixture through a plurality of molecular sieve stages containing sieves of different pore sizes each sieve retaining a fraction of the homologues, and separately removing the hydrocarbons adsorbed in each molecular sieve stage. The homologues may be n-paraffins, n-olefins or n-acetylenes separated by sieves of pore size 4-11 . The pore size of the sieves in each stage may increase or decrease in the direction of the flow of the mixture. Preferably lower molecular weight homologues adsorbed in the last or later stages are recovered by desorption with an inert gas, e.g. paraffin-free gas from a cracking or hydrogenation process, and the recovered light hydrocarbons are used to desorb the heavier hydrocarbons; in this case the later stages should have a larger capacity than earlier stages. Preferably two sets of sieves are used alternately in parallel, one on adsorption the other on desorption.