Process and apparatus for the separation of crude benzol and naphthalene

Abstract

A process and apparatus for the regeneration of washing oil which has been spent to recover naphthalene and/or benzol from coke oven gas. The spent washing oil is stripped by steam in a bubble column arranged as an integral part of a single main column that includes first, second and third exchange column sections disposed in a superimposed relation one above the other to receive the stripped vapors from the bubble column. The first exchange column section is fed with a mixture of toluene, xylene and naphthalene as a reflux, the second exchange column section is fed with water as the reflux and the third exchange column section is fed with benzol as the reflux. The head product from the column is condensed and passed through a first-phase separator to obtain a substantially anhydrous benzol fraction and a water fraction. These fractions are separately used as a reflux for the second and third exchange column sections. The liquid mixture drawn off from the second exchange column section is separated in a second-phase separator into a water phase and into a substantially anhydrous toluene-xylene-naphthalene phase. The latter is resolved by steam distillation in a secondary column having stripping and rectifying sections for resolving into a toluene-xylene fraction and a naphthalene fraction.