Method for Producing Butadiene from N-Butane

• Main Authors: SCHINDLER GOTZ-PETER, BORGMEIER FRIEDER, CRONE SVEN, DUDA MARK, KLANNER CATHARINA
• Format: Patent
• Language: English
• Published: 22.05.2008
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

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 gas stream b comprising n-butane, 1-butene, 2-butene, butadiene and hydrogen, with or without steam, with or without carbon oxides and with or without inert gases; C) feeding the gas stream b and an oxygenous gas into at least one second dehydrogenation zone and oxidatively dehydrogenating 1-butene and 2-butene to obtain a gas stream c comprising n-butane, butadiene, hydrogen, steam, with or without carbon oxides and with or without inert gases; D) compressing in at least one first compression stage and cooling the gas stream c to obtain at least one condensate stream d1 comprising water and a gas stream d2 comprising n-butane, butadiene, hydrogen and steam, with or without carbon oxides and with or without inert gases; E) separating the gas stream d2 by extractive distillation into a product stream e1 consisting substantially of butadiene and a stream e2 comprising n-butane, hydrogen and steam, with or without carbon oxides and with or without inert gases, F) if appropriate compressing in one or more further compression stages and cooling the gas stream e2 to obtain at least one condensate stream f1 comprising n-butane and water, and a gas stream f2 comprising n-butane and hydrogen, with or without carbon oxides and with or without inert gases, and if appropriate recycling the condensate stream f1 into the first dehydrogenation zone; G) separating the gas stream f2 into a recycle stream g1 comprising n-butane and an offgas stream g2 comprising hydrogen, with or without carbon oxides and with or without inert gases, by contacting the gas stream f2 with a high-boiling absorbent and subsequently desorbing the gas constituents dissolved in the absorbent.