PROCESS FOR THE MANUFACTURE OF 1,2-DICHLOROETHANE

摘要

Process for the manufacture of 1,2-dichloroethane starting from a stream of ethane according to which: a) the stream of ethane is subjected to a catalytic oxydehydrogenation producing a gas mixture containing ethylene, unconverted ethane, water and secondary constituents; b) said gas mixture is optionally washed and dried thus producing a dry gas mixture; c) after an optional additional purification step, said dry gas mixture is subjected to an absorption Al which consists of separating said gas mixture into a fraction enriched with the compounds that are lighter than ethylene containing some of the ethylene (fraction A) and into a fraction Fl; d) fraction A is conveyed to a chlorination reactor in which most of the ethylene present in fraction A is converted to 1,2-dichloroethane and optionally the 1,2-dichloroethane obtained is separated from the stream of products derived from the chlorination reactor; e) optionally the stream of products derived from the chlorination reactor, from which the 1,2-dichloroethane has optionally been extracted, is subjected to an absorption A2 which consists of separating said stream into a fraction enriched with ethane F2 which is then conveyed back to fraction Fl, and into a fraction enriched with compounds that are lighter than ethane F2'; f) fraction Fl, optionally containing fraction F2 recovered in step e) of absorption A2, is subjected to a desorption D which consists of separating fraction Fl into a fraction enriched with ethylene (fraction B) and into a fraction F3, optionally containing the 1,2-dichloroethane formed in the chlorination reactor then extracted if it has not been extracted previously, which is recycled to at least one of the absorption steps, optionally after an additional treatment intended to reduce the concentration of compounds that are heavier than ethane in fraction F3; g) fraction B is conveyed to an oxychlorination reactor in which most of the ethylene present in fraction B is converted into 1,2-dichloroethane, the 1,2- dichloroethane obtained is separated from the stream of products derived from the oxychlorination reactor and is optionally added to the 1,2-dichloroethane formed in the chlorination reactor; and h) the stream of products derived from the oxychlorination reactor, from which the 1,2-dichloroethane has been extracted, optionally containing an additional stream of ethane previously introduced in one of steps b) to g), is optionally recycled to step a) after having been optionally purged of gases and/or after an optional treatment in order to eliminate the chlorinated products contained therein.