| abstract |
The invention relates to a method for producing butadiene from n-butenes having the steps:n A) providing a feed gas stream a comprising n-butenes; B) feeding the feed gas stream a comprising the n-butenes 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, possibly carbon oxides and possibly 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 stage, wherein at least one aqueous condensate stream c 1 and a gas stream c 2 comprising butadiene, n-butenes, steam, oxygen, low-boiling hydrocarbons, possibly carbon oxides and possibly inert gases are obtained; Da) separating off non-condensable and low-boiling gas components comprising oxygen, low-boiling hydrocarbons, possibly carbon oxides and possibly inert gases as gas stream d 2 from the gas stream c 2 by absorbing the C 4 hydrocarbon-comprising butadiene and n-butenes in an absorbent, wherein an absorbent stream loaded with C 4 hydrocarbons and the gas stream d 2 are obtained, and Db) subsequent desorption of the C 4 hydrocarbons from the loaded absorbent stream in a desorption column, wherein a C 4 product gas stream d 1 is obtained,n nwherein a polymerization inhibitor is added in step Db) at the column head of the desorption column. |