METHOD OF SEPARATING ISOPENTANE-PENTANE-HEXANE FRACTION Russian patent published in 2013 - IPC C07C7/04 C07C5/27 C07C9/18 C07C9/10 C07C9/16 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of separating an isopentane-pentane-hexane fraction during an isomerisation process, consisting of a first fractionation column for preparing material, from which the ballast product contained in the material is separated with the distillate. The residue from the bottom of the fractionation column is taken for conversion of pentanes and hexanes into isomers in an isomerisation reactor. Isomerisation products are fed into a second fractionation column for debutanisation, from where butane is removed from the top of the column and the isomerisation product is removed from the bottom of the column, said product containing reaction isomers obtained during the reaction, which are fed for separation into a third fractionation column for depentanisation, from which isopentane, recycled pentane and a hexane fraction are successively removed from the top. The recycled pentane is returned into the isomerisation reactor. The method is characterised by that the starting material used is a 75-85°C fraction of straight-run gasoline, and the ballast product removed from the top of the first fractionation column is isopentane contained in the material; reaction isopentane is removed from the top of the third fractionation column for depentanisation as a distillate or with the first side cut. Excess butane is removed as the distillate. Pentane is removed with the second side cut of the depentanisation column and fed into the isomerisation reactor as a recycle stream. A mixture of isohexane and normal hexane is removed from the bottom of the depentanisation column and then fed as material into an additional fourth fractionation column for deisohexanisation, from which the isohexane fraction is removed with the distillate and recycled hexane is removed with the side cut and then fed for re-conversion into the isomerisation reactor, and higher-boiling components are removed with the residue.

EFFECT: use of the present method enables to cut the amount of energy spent in the isomerisation process on producing isoparaffins, widens the range of products and provides flexibility of the process and purity of the end products.

2 cl, 4 tbl, 1 dwg