Regeneration of spent catalysts - by extn. of reaction prods. via liq. gas, esp. when catalyst has been used for hydrogenation of fats

摘要

The catalysts are used in (de)hydrogenation-, oxidn.-, and polymerisation- processes; and the extn. medium is a fluid consisting of a gas in a supercritical state. The fluid is then pref. expanded to below its critical pressure so it becomes sepd. from the extracted reaction prods.; it is next recompressed and returned to the extn. process. The catalyst consists esp. of Ni or Cu, and is used for the hydrogenation of fats, esp. where the catalyst is located on a carrier made of metal oxide, e.g. Al2O3, MgO or SiO2 such as diatomite. The extn. medium is esp. CO2. After removing the main part of the reaction prods., the remainder is pref. removed from the spent catalyst by distn. at 250-400 degrees C in a counter-current of H2 in appts. described e.g. in DT 2403998. When a catalyst appears spent, it still contains a substantial amt. of active material, which may include noble metals. The invention removes reaction prods. so the catalyst may be reclaimed.