ZSM-5-containing catalytic additives are widely used in oil refineries to boost light olefin production and improve gasoline octanes in the Fluid Catalytic Cracking (FCC) process. Under the hydrothermal conditions present in the FCC regenerator (typically >700 °C and >8% steam), FCC catalysts and additives are subject to deactivation. Zeolites (e.g., Rare Earth USY in the base catalyst and ZSM-5 in Olefins boosting additives) are prone to dealumination and partial structural collapse, thereby losing activity, micropore surface area, and undergoing changes in selectivity. Fresh catalyst and additives are added at appropriate respective levels to the FCC unit on a daily basis to maintain overall targeted steady-state (equilibrated) activity and selectivity. To mimic this process under accelerated laboratory conditions, a commercial P/ZSM-5 additive was hydrothermally equilibrated via a steaming process at two temperatures: 788 °C and 815 °C to simulate moderate and more severe equilibration industrial conditions, respectively. n-Dodecane was used as probe molecule and feed for micro-activity cracking testing at 560 °C to determine the activity and product selectivity of fresh and equilibrated P-doped ZSM-5 additives. The fresh/calcined P/ZSM-5 additive was very active in C12 cracking while steaming limited its activity, i.e., at catalyst-to-feed (C/F) ratio of 1, about 70% and 30% conversion was obtained with the fresh and steamed additives, respectively. A greater activity drop was observed upon increasing the hydrothermal deactivation severity due to gradual decrease of total acidity and microporosity of the additives. However, this change in severity did not result in any selectivity changes for the LPG (liquefied petroleum gas) olefins as the nature (Brønsted-to-Lewis ratio) of the acid/active sites was not significantly altered upon steaming. Steam deactivation of ZSM-5 had also no significant effect on aromatics formation which was enhanced at higher conversion levels. Coke remained low with both fresh and steam-deactivated P/ZSM-5 additives.

We investigated the roles of nickel and vanadium in the properties of ZSM-5 additives and in the fluid catalytic cracking (FCC) products, yielding 4000 and 12 000 ppm loadings of Ni + V. The ZSM-5 additive was deactivated in a cyclic deactivation unit (CDU), where cracking–regeneration reactions were carried out with vacuum gas oil (VGO) spiked with Ni and V naphthenates. Characterization of the deactivated ZSM-5 additives with N2 physisorption, SEM, and pyridine FTIR techniques showed a uniform Ni distribution across a particle, little variation in the Brønsted acidity, and an increase in Lewis acidity, when Ni and V were added. Tests were carried out in a short contact time microactivity test (SCT-MAT) unit with ZSM-5 and n-hexane and blends of equilibrium catalyst (ECAT) and ZSM-5 with VGO. With hexane Ni and V, the dehydrogenation, aromatization, and coking reactions are enhanced. With VGO, the metals were found to decrease the propylene selectivity whereas that of butylene increased.

Many fintech start-ups participant companies and cryptocurrencies have experienced phenomenal growth in value during the past several years. Many specialists would like to know the reasons for such success. In this article we investigate the predictive power of public opinions. This is one of the few works that using quantitative analysis connects social media and internet users' activities with cryptocurrency valuations.