Effect of Feedstock and Catalyst Impurities on the Methanol‐to‐Olefin Reaction over H‐SAPO‐34

Abstract

Operando UV/Vis spectroscopy with on‐line mass spectrometry was used to study the effect of different types of impurities on the hydrocarbon pool species and the activity of H‐SAPO‐34 as a methanol‐to‐olefins (MTO) catalyst. Successive reaction cycles with different purity feedstocks were studied, with an intermittent regeneration step. The combined study of two distinct impurity types (i.e., feed and internal impurities) leads to new insights into MTO catalyst activation and deactivation mechanisms. In the presence of low amounts of feed impurities, the induction and active periods of the process are prolonged. Feed impurities are thus beneficial in the formation of the initial hydrocarbon pool, but also aid in the unwanted formation of deactivating coke species by a separate, competing mechanism favoring coke species over olefins. Further, feedstock impurities strongly influence the location of coke deposits, and thus influence the deactivation mechanism, whereas a study of the organic impurities retained after calcination reveals that these species are less relevant for catalyst activity and function as “seeds” for coke formation only.

Recent trends and fundamental insights in the methanol-to-hydrocarbons process

“…The combined effort by several research groups helped identify several feasible low-barrier direct coupling pathways for this key mechanistic step, although feedstock impurities (in principle) could still shorten the induction period. 115 Among them, formaldehyde formed through disproportionation of methanol was identified as a deactivating species due to its high reactivity with aromatics and the undesired formation of poly-aromatic species. This important discovery calls for new reactor concepts where reactant feeding should be performed carefully to avoid high concentrations of methanol and the consequences thereof, including heat effects.…”

Kinetic and Deactivation Differences Among Methanol, Dimethyl Ether and Chloromethane as Stock for Hydrocarbons

“…Experiments were carried out by feeding methanol (Sigma‐Aldrich, 99.8 %), dimethyl ether (Air liquid, 99.9 %), and chloromethane (Alpha Gaz, 99.999 %) with He as diluent (15 mol%) in an isothermal fixed bed reactor under the following operating conditions: 400 °C; 1.5 atm; space time, n BAS /F=6.49–2048 μmol BAS h mol CH3 −1 . The purity of these reactants have been found to have a critical role in the overall process performance . The bed consists of a mixture of catalyst and SiC (inert and diluent, supplied by Prolabo).…”

“…The purity of these reactants have been found to have a critical role in the overall process performance. [81] The bed consists of a mixture of catalyst and SiC (inert and diluent, supplied by Prolabo). The HCl formed during the CTH reaction was removed by using two fixed bed adsorption reactors in series, made of a mixture of CaCO 3 (95 wt%) and Laponite (5 wt%).…”

Tanabe‐Preis für Säure‐Base‐Katalyse und Robert B. Anderson Catalysis Award: B. M. Weckhuysen / MRS Outstanding Young Investigator Award: J. A. Dionne und J. M. Rondinelli / VAAM‐Forschungspreis: T. J. Erb

“…Sein Forschungsthema ist die Entwicklung von In‐situ‐ und Operando‐Spektroskopie‐ und ‐Mikroskopietechniken zur Untersuchung katalytischer Feststoffe unter realistischen Reaktionsbedingungen. In ChemCatChem beschrieb er Katalysatoren für die Überführung von Methanol in Olefine, und seine Arbeit über die Erforschung der Kristallarchitekturen von Zeolithen wurde auf dem Titelbild von Chemistry—A European Journal vorgestellt . Weckhuysen war 2009–2016 Covorsitzender des Editorial Board von ChemCatChem und gehört derzeit dessen International Advisory Board an.…”