Method of separation of hydrocarbons retained in a straight chain of petroleum fractions boiling in the range of c10 to c20

摘要

A vapour phase process for separating straight chain hydrocarbons from petroleum fractions boiling in the C10-C20 range comprises (1) contacting the fractions with a 5 rA mol. sieve to absorb straight chain hydrocarbons, (2) contacting the sieve with a purging medium to remove material superficially absorbed or held interstitially between sieve particles, and (3) desorbing the straight chain hydrocarbons with n-pentane or n-butane at a pressure equal to or greater than the pressure in the absorption stage. Feedstock is preferably pretreated to reduce the sulphur content to 0.005-0.015% weight and the temperature and pressure of the absorption and purging steps lie within the ranges 300-450 DEG C., preferably 350-390 DEG C., and 50-300 p.s.i.g., preferably 100-150 p.s.i.g. The desorption is preferably carried out at 0-100 p.s.i.g. higher than the absorption pressure. A guard bed 2, containing a 4 rA molecular sieve to remove water and polar substances, is provided. The Provisional Specification is not restricted to desorption with n-butane or n-pentane.