Dehydrogenation cycle

The C60H36 hydride contains 4.76 mass% of hydrogen. It can be used as hydrogen accumulator because in the temperature of 400-600 K the hydrogenation-dehydrogenation cycles are thermodynamically allowable. The thermodynamic parameters and equilibrium hydrogen pressures for the reaction... 

The thermodynamic analysis allowed us to determine the most favorable parameters of hydrogenation-dehydrogenation cycles in the system C60 + 18 H2 = C60H36 under the conditions of thermodynamic control. 

The hydrogenation/dehydrogenation cycles result in the elimination of subsurface trap sites in the palladium, presumably by removal of dislocations and lattice defects. Indications of differences in the relaxation phenomena of small, supported, and coarse unsupported hydrogenated particles of palladium were observed. 

Figure 5.8 The release of hydrogen (wt.%) vs. 100 dehydrogenation cycles. (Reproduced from [117], with permission from Elsevier.)...

Entrained catalyst is removed from the product off-gas by means of cyclones. The catalyst circulates continuously from the reactor to the regenerator and vice versa by means of transfer lines. Coke deposited on the catalyst is burnt off in the regenerator however, because the amount of coke is relatively small, additional fuel must be burnt in the regenerator to satisfy the thermal requirements of the endothermic dehydrogenation reaction. However, while this approach is similar to that in the Houdry process, FED does not have a catalyst reduction step with hydrogen before proceeding to the dehydrogenation cycle lack of this step is believed to be somewhat detrimental to the overall performance of the process. 

Several other primary alcohols could be converted in this manner into the corresponding alkanes and syngas. A mechanism was suggested, consisting of a decarbonylation and a dehydrogenation cycle, with a coordinatively unsaturated iridium complex as common intermediate (Scheme 3.21). 

This example, unlike those of the first group, is characterized by the fact that not all the components in each section of the process undergo chemical conversion. Thus, for example, the first process in this plant that is included in the diagram of the movement of the flows (Fig. 14(6)), is designed simply to distil the components, and thus the flow that is recycled from the dehydrogenation cycle alters the ratio of the components in this apparatus, while the presence of isobutane in the latter in turn alters the ratio of the components in the alkylation, isomerization and dehydrogenation sections of the plant. 

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