METHOD OF ISOMERISING NORMAL BUTANE TO ISOBUTANE AND DEVICE FOR REALISING SAID METHOD Russian patent published in 2009 - IPC C07C5/27 C07C9/12 C07C7/144 B01J8/00 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of isomerising normal butane containing initial material, containing at least 50 wt % normal butane to an isomerate which contains isobutane, involving: (a) isomerisation of the initial material under isomerisation conditions, involving presence of isomerisation catalyst, until an output isomerisation stream is obtained, containing normal butane, but with less concentration than in the initial isomerisation material; (b) distillation of at least part of the output isomerisation stream until a low-boiling fraction is obtained, containing isobutane and light paraffins, where at least 80 wt % of the low-boiling fraction is isobutane, and a high-boiling fraction, containing normal butane and at least 10 wt % isobutane; (c) bringing at least part of the fraction containing normal butane from stage (b) into contact with medium at the retentate side of a permeation-selective membrane, with efficiency index of flow of C4 permeate equal to at least 0.01 and pressure difference between media on both sides of the membrane, which allows for obtaining a retentate fraction containing at least 80 wt % isobutane, and for obtaining a permeate fraction at the permeate side, after passage through the membrane, with high concentration of normal butane; and (d) tapping off retentate fraction from stage (c).

EFFECT: simplification of method.

10 cl, 2 dwg