| 摘要 |
A process for preparing butadiene from n-butane, comprising the steps of A) providing a feed gas stream a comprising n-butane; B) feeding the feed gas stream a comprising n-butane into at least one first dehydrogenation zone and nonoxidatively catalytically dehydrogenating n-butane to obtain a product gas stream b comprising n-butane, 1-butene, 2-butene, butadiene, hydrogen and low-boiling secondary constituents, with or without carbon oxides and with or without steam; C) feeding the product gas stream b of the nonoxidative catalytic dehydrogenation and an oxygenous gas into at least one second dehydrogenation zone and oxidatively dehydrogenating n-butane, 1-butene and 2-butene to obtain a product gas stream c comprising n-butane, 2-butene, butadiene, low-boiling secondary constituents, carbon oxides and steam, said product gas stream c having a higher content of butadiene than product gas stream b; D) removing the low-boiling secondary constituents and steam to obtain a C<SUB>4 </SUB>product gas stream d substantially consisting of n-butane, 2-butene and butadiene; E) separating the C<SUB>4 </SUB>product gas stream d into a stream e 1 consisting substantially of n-butane and 2-butene and a product-of-value stream e 2 consisting substantially of butadiene by extractive distillation; F) recycling stream e 1 into the first dehydrogenation zone.
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