Method for preparing 1,3-butadiene from N-butenes by oxidative dehydrogeneation

Abstract

The invention relates to a method for producing butadiene from n-butenes having the steps: A) providing an n-butene-comprising feed gas stream a; B) feeding the n-butene-comprising feed gas stream a and an oxygen-comprising gas into at least one oxidative dehydrogenation zone and oxidatively dehydrogenating n-butenes to butadiene, wherein a product gas stream b comprising butadiene, unreacted n-butenes, steam, oxygen, low-boiling hydrocarbons, high-boiling minor components, optionally carbon oxides and optionally inert gases is obtained; Ca) cooling the product gas stream b by contacting it with a refrigerant and condensing at least a part of the high-boiling minor components; Cb) compressing the remaining product gas stream b in at least one compression step, wherein at least one aqueous condensate stream c1 and a gas stream c2 comprising butadiene, n-butenes, steam, oxygen, low-boiling hydrocarbons, optionally carbon oxides and optionally inert gases is obtained; Da) separating off non-condensable and low-boiling gas components comprising oxygen, low-boiling hydrocarbons, optionally carbon oxides and optionally inert gases as gas stream d2 from the gas stream c2 by absorbing the C4 hydrocarbons comprising butadiene and n-butenes in an absorption medium, wherein an absorption medium stream loaded with C4 hydrocarbons and the gas stream d2 are obtained, and Db) subsequently desorbing the C4 hydrocarbons from the loaded absorption medium stream in a desorption column, wherein a C4 product gas stream d1 is obtained, Dc) separating off the steam condensate from the absorption medium in a phase separator and vaporizing it in a steam generator and providing it again as stripping gas in the desorption column, wherein, the steam condensate before the vaporization in a steam generator, is subjected to a pretreatment in a further method step.

Dependencies are inferred from the claim text.