Thermodynamics continuous catalyst regeneration

Dehydrogenation of /i-Butane. Dehydrogenation of / -butane [106-97-8] via the Houdry process is carried out under partial vacuum, 35—75 kPa (5—11 psi), at about 535—650°C with a fixed-bed catalyst. The catalyst consists of aluminum oxide and chromium oxide as the principal components. The reaction is endothermic and the cycle life of the catalyst is about 10 minutes because of coke buildup. Several parallel reactors are needed in the plant to allow for continuous operation with catalyst regeneration. Thermodynamics limits the conversion to about 30—40% and the ultimate yield is 60—65 wt % (233). 

Regeneration of the reduced metal ion by redox reaction during catalysis is essential to continue PO degradation. Fe is the thermodynamically favored oxidation state for iron under aerobic and alkaline conditions, whereas Fe is favored under anaerobic and acidic conditions. Under most disposal and environmental conditions Mn " is favored. It is therefore unlikely that a particular metal catalyst will perform equally well in a wide range of disposal situations. Due to environmental pH values it is difficult for such catalysts to be recycled for further free radical generation. Both Fe and Fe " salts can precipitate as insoluble oxides or sulfides under environmental conditions, reducing the polymer degradation potential. 

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