Kinetic modelling of methanol synthesis over commercial catalysts: A critical assessment

Kinetic modelling of methanol synthesis over commercial catalysts is of high importance for reactor and process design. Literature kinetic models were implemented and systematically discussed against a newly developed kinetic model based on published kinetic data. Deviations in the sensitivities of the kinetic models were explained by means of the experimentally covered parameter range. The simulation results proved that an extrapolation of the working range of the kinetic models can lead towards significant simulation errors especially with regard to pressure, stoichiometric number and CO/CO$_{2}$-ratio considerably limiting the applicability of kinetic models frequently applied in scientific literature. Therefore, the validated data range for kinetic models should be considered when detailed reactor simulations are carried out. With regard to Power-to-Methanol processes special attention should be drawn towards the rate limiting effect of water at high CO$_{2}$ contents in the syngas. Moreover, it was shown that kinetic models based on data measured over outdated catalysts show significantly lower activity than those derived from state-of-the-art catalysts and should therefore be applied with caution for reactor and process simulations. The plausible behavior of the herein proposed kinetic model was demonstrated by a systematic comparison towards established kinetic approaches within both, an ideal kinetic reactor and an industrial steam cooled tubular reactor. Relative to the state-of-the-art kinetic models it was proven that the herein proposed kinetic model can be applied over the complete industrially relevant working range for methanol synthesis

Modeling of Acetylene Pyrolysis under Steel Vacuum Carburizing Conditions in a Tubular Flow Reactor

In the present work, the pyrolysis of acetylene was studied under steel vacuumcarburizing conditions in a tubular flow reactor. The pyrolysis temperature ranged from 650 °C to 1050 °C. The partial pressure of acetylene in the feed mixture was 10 and 20 mbar, respectively, while the rest of the mixture consisted of nitrogen. The total pressure of the mixture was 1.6 bar. A kinetic mechanism which consists of seven species and nine reactions has been used in the commercial computational fluid dynamics (CFD) software Fluent. The species transport and reaction model of Fluent was used in the simulations. A comparison of simulated and experimental results is presented in this paper

Peter Weiss: Briefe an Henriette Itta Blumenthal

»Liebe Itta – deine Briefe sind mir schon zu etwas ganz Unentbehrlichem geworden und jeden Tag, wenn ich in den Briefkasten vorm Haus sehe, tue ichs mit dem Gedanken: ob wohl von dir etwas dabei ist«, schrieb der 24-jährige Peter Weiss im Frühjahr 1941 an Henriette Itta Blumenthal. Ihr Briefwechsel erstreckt sich über zwei Jahre, von April 1941 bis Mai 1943; die Briefe sind das Zeugnis einer kurzen, aber intensiven und intimen Freundschaft und Selbstoffenbarung und markieren den Anfang einer Seelenforschung, die Peter Weiss über zwei Psychoanalysen schließlich zur Niederschrift seiner autobiografisch inspirierten Romane führt