Transformations of an industrial zeolite-based fluid catalytic cracking (FCC) catalyst and its coke deposits during regeneration following FCC reactions of a representative refinery stream are investigated.

A CeO2/α‐Al2O3 bilayer was coated on a high temperature alloy (Incoloy 800H) by sol–gel dip‐coating and was evaluated for its potential as an anticoking barrier and coke oxidation catalyst. The bilayer effectively functioned as a barrier to metal surface catalyzed coking. The film prevented filamentous catalytic coking via blocking surface active metallic sites on the Incoloy substrate. Furthermore, the bilayer reduced the oxidation temperature of pyrolytic coke deposited on the film surface as compared to a bare oxidized Incoloy substrate, mostly owing to the oxidation catalytic activity of the CeO2 layer. Finally, it is demonstrated that the presence of the α‐Al2O3 buffer layer is critically important to the overall performance. Without the α‐Al2O3 layer, a CeO2 layer nearly completely lost both its barrier and oxidation catalytic functions. It is presumed that metallic species migrating from the substrate during high temperature treatments are responsible for the CeO2 deactivation, likely by blocking catalytic sites on the CeO2 surface. © 2018 American Institute of Chemical Engineers AIChE J, 64: 4019–4026, 2018

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The learning from operational incidents plays a key role in improving the performance and safety of the chemical process plants. In this article, the incidents occurred during January 2011 to April 2012 in different sections, that is, Ammonia, Urea, and Utility Units of fertilizer sector in Pakistan have been analyzed using Why Tree analysis. The aim is to identify the failures in the safety management system to prevent the incidents. One thousand and fifteen, root and contributing causes identified in investigations strongly assert that improvement in safety management systems could have prevented or mitigated the intensity of many of the occurred incidents/accidents. The flaws in mechanical integrity, maintenance procedures and operating procedures, and job risk assessment are the most common recurrent as root cause failures of safety management system. © 2014 American Institute of Chemical Engineers Process Saf Prog 33: 399–404, 2014

Zeolite catalysts with pronounced two‐dimensional (2D) morphologies, specifically 2D MFI nanosheets composed of multilamellar stacks of MFI nanosheets, are hypothesized to offer accessibility advantages in catalytic reactions involving large, bulky molecules. The Si/Al ratio of zeolite catalysts is an important parameter determining their performance. However, the effect of Si/Al ratio on catalytic reactivity is not well understood in 2D zeolite catalysts. To provide further insight into this issue, the catalytic performance of 2D MFI nanosheet materials with different Si/Al ratios is compared using the liquid phase Friedel‐Crafts alkylation of mesitylene with benzyl alcohol & the self‐etherification of benzyl alcohol that occurs in parallel, both of which are catalyzed by Brønsted acid sites. The turnover frequency (TOF) of the catalysts is found to decrease with decreasing Si/Al ratio, with the etherification reaction being the main contributor to this trend. When the same reaction is carried out in the presence of a bulky poison, 2,6 di‐tert‐butylpyridine (DTBP), to selectively deactivate the external acid sites, only the etherification reaction of benzyl alcohol takes place in the micropores of the 2D MFI catalyst and the effectiveness factor is found to decrease with decreasing Si/Al ratio. The single component adsorption isotherms of benzyl alcohol show that the uptake normalized per acid site decreases with decreasing Si/Al ratio. Thus, increasing the density of acid sites in the micropores by decreasing the Si/Al ratio makes it more difficult for the reactant molecules to access them, as demonstrated by the decrease in TOF and the effectiveness factor. While the micropore reactions (benzene alkylation, alcohol etherification) showed a clear trend with Si/Al ratio, the reaction catalyzed on the external surface (mesitylene alkylation) did not, showing distinct differences in reactivity.