Technology for dehydrogenation of n-butane to make butadiene. The CATADIENE process uses specially formulated proprietary catalyst from Süd-Chemie.
The CATADIENE reaction system consists of parallel fixedbed reactors and a regeneration air system. The reactors are cycled through a sequence consisting of reaction, regeneration and evacuation/purge steps. Multiple reactors are used so that the reactor feed/product system and the regeneration air system operate in a continuous manner.
Fresh n-butane feed is combined with recycle feed from a butadiene extraction unit. The total feed is then vaporized and raised to reaction temperature in a charge heater (1) and fed to the reactors (2). Reaction takes place at vacuum conditions to maximize n-butane conversion and butadiene selectivity. The reactor effluent gas is quenched with circulating oil, compressed (3) and sent to the recovery section (4), where inert gases, hydrogen and light hydrocarbons are separated from the compressed reactor effluent. Condensed liquid from the recovery section is sent to a depropanizer (5), where propane and lighter components are separated from the C4s. The bottoms stream, containing butadiene, n-butenes and n-butane, is sent to an OSBL butadiene extraction unit, which recovers butadiene product and recycles n-butenes and n-butane back to the CATADIENE reactors.
After a suitable period of onstream operation, feed to an individual reactor is discontinued and the reactor is reheated/regenerated. Reheat/regeneration air heated in the regeneration air heater (6) is passed through the reactors. The regeneration air serves to restore the temperature profile of the bed to its initial onstream condition in addition to burning coke off the catalyst. When reheat/regeneration is completed, the reactor is re-evacuated for the next onstream period.
The low operating pressure and temperature of CATADIENE reactors, along with the robust Süd-Chemie catalyst, allow the CATADIENE technology to process n-butane feedstock with stable operation and without fouling of process equipment. The simple reactor construction, with its simple internals, results in very high on stream factors for the
Butadiene yield: The consumption of n-butane (100%) is 1.67 metric ton (mt) per mt of butadiene product.
Licensor: Lummus Technology