Philippe Arpentinier

Deactivation of a Pt/γ-Al2O3 catalyst in the partial oxidation of methane to synthesis gas

The deactivation of a Pt/-Al2O3 catalyst used in an industrial plant for the partial oxidation of methane to synthesis gas was investigated. Four samples at different time-on-stream in air were characterized and their catalytic performances were tested in a micro-reactor in order to shed light on the causes and the effects of this deactivation. The high temperatures (about 900 ◦ C) reached while operating in the industrial plant, promoted modifications to the -Al2O3, inducing sintering phenomena and, therefore, deactivation effects. The not used sample showed good values of yield in syngas (compared with equilibrium values), but these performances decreased quickly with time-on-stream.

Property value estimation for inhaled therapeutic binary gas mixtures: He, Xe, N2O, and N2 with O2

BackgroundThe property values of therapeutic gas mixtures are important in designing devices, defining delivery parameters, and in understanding the therapeutic effects. In the medical related literature the vast majority of articles related to gas mixtures report property values only for the pure substances or estimates based on concentration weighted averages. However, if the molecular size or structures of the component gases are very different a more accurate estimate should be considered.FindingsIn this paper estimates based on kinetic theory are provided of density, viscosity, mean free path, thermal conductivity, specific heat at constant pressure, and diffusivity over a range of concentrations of He-O2, Xe-O2, N2O-O2 and N2-O2 mixtures at room (or normal) and body temperature, 20 and 37°C, respectively and at atmospheric pressure.ConclusionsProperty value estimations have been provided for therapeutic gas mixtures and compared to experimental values obtained from the literature where possible.

New catalysts for the syngas production obtained by hydrotalcite type precursor containing silicate

Publisher Summary Ni and/or Rh based catalysts (ex-HT) derived by hydrotalcite precursor are considered to be effective catalysts in the catalytic partial oxidation (CPO) reaction. This chapter discusses new stable ex-HT catalysts prepared by inserting silicate instead of CO 3 2- anions in the interlayer. The amount of silicates is not limited by the charge balance of the cations, because, an excess of silicates leads to the formation of polysilicate anions. The insertion of silicates affects the structure of the calcined samples, because, unlike CO 3 2- , the silicates remain in the structure and contribute to the formation of the final catalysts. Catalysts with innovative structure are obtained by HT precursor prepared using silicate as interlayer anion. The calcined catalysts showed two phases—a mixed oxide type structure and a new M-silicate structure, where the cations of the active metal are partially soluted. The Rh catalyst prepared by HT silicate was more active and selective than the one prepared by CO 3 2- .