CATALYTIC AND REACTION ENGINEERING ASPECTS IN THE STORAGE OF HYDROGEN THROUGH THE REVERSIBLE DEHYDROGENATION OF CYCLOHEXANE.

Hydrogen as an energy carrier has several advantages, especiallyith regard to its storage and transmission possibilities. Present technology already offers proven ways for handling and storage (cryogenic, pressurized, hydrides, hollow spheres) but lacks suitable means for both storage and long-distance transportation. Reversible catalytic (de)hydrogenation reactions appear a possible solution to this problem. An obvious limitation is complete reversibility, a quality hard to achieve, unless selective catalysts are developed. Work carried out in authors institute has proven the (de) hydrogenation of cyclohexane to be best suited for that purpose and meeting the requirements of full reversibility taking advatnage of newly developed highly selective catalysts developed in this laboratory. Concepts underlying catalytic aspects of this specific catalyst, choice of reactor and process design engineering are outlined for a closed-loop cycle characterized by three phases: hydrogen storage (charge); cyclohexane transportation and release of hydrogen (discharge). Together with process design characteristics, an account is given of the results on catalyst characterization namely on the nature of active sites and the kinetical-diffusional behavior in fixed-bed operations (from micro-reactor experiments). Proven advantages of this novel class of catalysts are emphasized.