A process for preparing butadiene from n-butane

"PROCESS FOR PREPARATION OF BUTADIENE The n-BUTANE FROM". The invention relates to a method for producing butadiene from n-butane comprising the steps of A) providing an incoming gas stream containing n-butane; B) feeding said feed gas stream containing n-butane at least one first dehydrogenation zone and dehydrogenating n-butane to a nonoxidative catalytic manner to obtain a product gas stream b comprising n-butane , 1-butene, 2-butene, butadiene, hydrogen, secondary components with low boiling point and optionally steam; C) feeding the product gas stream b resulting from the non-oxidative catalytic dehydrogenation process and an oxygen-containing gas in at least one second dehydrogenation zone and dehydrogenating oxidatively 1-butene and 2-butene, being obtained a product gas flow and containing n-butane, 2-butene, butadiene, hydrogen, low-side components boiling and steam, said second product gas stream c having a higher content of butadiene than the product gas stream b; D) removing hydrogen, the secondary components of low boiling and steam being obtained a product gas stream d ~ C ~ 4, containing mainly n-butane, 2-butene and butadiene; E) separating the product gas stream -C4 d into a recycle stream e1 mainly containing n-butane and 2-butene and e2 stream substantially containing butadiene by extractive distillation, and redirect the E1 flow into the first dehydrogenation zone .