Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

摘要

Interest in the use of catalysts containing noble metals (NMs) in various hydroprocessing (HPR) applications is the result of an increasing volume of unconventional feeds and a continuous change in performance parameters of petroleum products. Conventional HPR catalysts can only partially fulfill new requirements. The high price of NMs and their high activity under both reducing and oxidative atmospheres require some modifications of the strategies that have been used for the handling of spent conventional HPR catalysts. Because of their higher activity, the deactivation of NMs-containing catalysts during HPR occurs under less severe conditions compared with that of conventional HPR catalysts. However, adverse effects of sulfur, nitrogen, oxygenates, and metals in feeds may require a higher severity to achieve HPR objectives. The activity of spent NMs-containing catalysts can be almost completely recovered by regeneration. The oxidative regeneration of spent NMs-containing catalysts has been performed commercially, while reductive and extractive regenerations offer alternative routes. The high value of NMs dictates that metal recovery is the only option if an adequate catalyst activity recovery cannot be achieved by regeneration. The methods are available for NMs recovery on an industrial scale. Also, the research aiming at improvement of metals recovery via existing methods as well as development novel methods has been noted.