Accelerated deactivation of Co/Al2O3 catalysts in Fischer-Tropsch synthesis and the effect of Re and Ru as the catalytic promoters are reported. 15wt% Co/Al2O3 catalyst and 1wt% Ru and 1.4wt% Re  promoted cobalt catalysts have been formulated and extensively characterized. The deactivation of the unpromoted cobalt catalyst and those promoted with ...

accelerated deactivation of co/al2o3 catalysts in fischer-tropsch synthesis and the effect of re and ru as the catalytic promoters are reported. 15wt% co/al2o3 catalyst and 1wt% ru and 1.4wt% re  promoted cobalt catalysts have been formulated and extensively characterized. the deactivation of the unpromoted cobalt catalyst and those promoted with re and ru were studied by accelerated method at ...

Although catalyst deactivation rate greatly varies depending on many factors, including the catalyst structure, reactor feed composition, and operating conditions; it is usually inevitable. Since catalyst deactivation modeling has so far been poorly addressed in the literature, in the present study, nine experimental sets of cobalt based Fischer-Tropsch catalysts activity-time data were conside...

Deactivation of the human brain's default mode network (DMN) is regarded as suppression of endogenous activity to support exogenous task-related processes. This phenomenon has important functional relevance and insufficient DMN deactivation has been implicated in several neuropsychiatric disorders. However, the neurochemical mechanism of the DMN's deactivation remains largely unknown. In the pr...

A study was made of the coking of a commercial fresh sulfide Ni-Mo/Al2O3 catalyst in a fixed-bed reactor. The catalyst was coked using different coke precursors in the gas oil under accelerated conditions at temperatures of 400 to 450°C to yield different deactivated catalysts containing 2-20 wt% C. Two cases were studied; crushed catalyst without diffusional ...

Reduced task deactivation within regions of the default mode network (DMN) has been frequently reported in Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI). As task deactivation reductions become increasingly used in the study of early AD states, it is important to understand their relationship to atrophy. To address this issue, the present study compared task deactivation...

The fundamentals of catalyst deactivation are presented in this review. The chemico-physical aspects concerning the various deactivation causes (i.e. poisoning, sintering, coking, solid-state transformation, masking, etc.) have been analyzed and discussed, along with the mathematical description of the deactivation phenomena. # 1999 Elsevier Science B.V. All rights

Deactivation of heterogeneous catalysts is a ubiquitous problem that causes loss of catalytic rate with time. This review on deactivation and regeneration of heterogeneous catalysts classifies deactivation by type (chemical, thermal, and mechanical) and by mechanism (poisoning, fouling, thermal degradation, vapor formation, vapor-solid and solid-solid reactions, and attrition/crushing). The key...