METHOD FOR THE OXIDATIVE DEHYDROGENATION OF N-BUTENES TO BUTADIENE

The invention relates to a method for producing butadine from n-butenens, consisting of the following steps: A) a feed gas flow (a) containing n-butenes is provided; B) the feed gas flow (a) containing n-butenes and an oxygen-containing gas is fed to at least one dehydrogenation area and is oxidatively dehydrogenated from n-butenes to form butadiene; a product gas flow (b) containing butadiene, unreacted n-butenes, water vapour, oxygen, low-boiling hydrocarbons, optionally carbon oxides and optionally inert gases is obtained; C) the product gas flow (b) is cooled and compressed in at least compression step; at least one condensate flow (c1) containing water and a gas flow (c2) containing butadiene, n-butenes, water vapour, oxygen, low-boiling hydrocarbons, optionally carbon oxides and optionally inert gases is obtained; D) non-condensable and low-boiling gas component parts containing oxygen, low-boiling hydrocarbons, optionally carbon oxides and optionally inert gases are separated from the gas flow (c2) by Da) absorbing C4-hydrocarbons containing butadiene and n-butenes in absorption means boiling at a high temperature, wherein an absorption agent flow charged with C4-hydrocarbons and the gas flow (d2) are obtained, Db) the oxygen is removed from the absorption agent flow charged with the C4-hydrocarbon by stripping with the inert gas, and Dc) the C4 hydrocarbons are desorbed from the charged absorption agent flow and a C4 -product gas flow (d1), which consists essentially of C4-hydrocarbons and has less that 100ppm oxygen, is obtained. E) the C4-product flow (d1) is separated by extractive distillation using a selected solvent for butadiene in a butadiene and the material flow (e1) containing the selective solvent and a material flow (e2) containing n-butenes; F) the butadiene and the material flow (e1) containing the selective solvent is distilled in a material flow (f1) consisting essentially of the selective solvent and a material flow (f2) containing a butadiene.