Method for preparing 1,3-butadiene from n-butenes by oxidative dehydrogenation

A method for producing butadiene from n-butenes having the steps:

• A) providing a feed gas stream a comprising n-butenes;
• B) feeding the feed gas stream a comprising 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, 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 stage, 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 are obtained;
• Da) separating off non-condensable and low-boiling gas components comprising oxygen, low-boiling hydrocarbons, optionally carbon oxides and optionally inert gases as a gas stream d2 from the gas stream c2 by absorbing C4 hydrocarbons comprising butadiene and n-butenes in an absorbent, wherein an absorbent stream loaded with C4 hydrocarbons and the gas stream d2 are obtained, and
• Db) subsequently desorbing the C4 hydrocarbons from the loaded absorbent stream in a desorption column, wherein a C4 product gas stream dl is obtained,
• wherein the desorption column comprises a top condenser located at a head of the column, and
• wherein a polymerization inhibitor is added in step Db) at the top condenser of the desorption column.