The oxygen-assisted transformation of propane to COx/H2 through combined oxidation and WGS reactions catalyzed by vanadium oxide-based catalysts

This paper reports about the gas-phase oxidation of propane catalyzed by bulk vanadium oxide and by alumina- and silica-supported vanadium oxide. The reaction was studied with the aim of finding conditions at which the formation of H2 and CO2 is preferred over that of CO, H2O and of products of alkane partial oxidation. It was found that with bulk V2O5 considerable amounts of H2 are produced above 400 8C, the temperature at which the limiting reactant, oxygen, is totally consumed. The formation of H2 derived from the combination of: (i) oxidation reactions, with generation of CO, CO2, oxygenates (mainly acetic acid), propylene and H2O, all occurring in the fraction of catalytic bed that operated in the presence of gas-phase oxygen, and (ii) WGS reaction, propane dehydrogenation and coke formation, that instead occurred in the fraction of bed operating under anaerobic conditions. This combination of different reactions in a single catalytic bed was possible because of the reduction of V2O5 to V2O3 at high temperature, in the absence of gas-phase oxygen. In fact, vanadium sesquioxide was found to be an effective catalyst for the WGS, while V2O5 was inactive in this reaction. The same combination of reactions was not possible when vanadium oxide was supported over high-surface area silica or alumina; this was attributed to the fact that in these catalysts vanadium was not reduced below the oxidation state V4+, even under reaction conditions leading to total oxygen conversion. In consequence, these catalysts produced less H2 than bulk vanadium oxide

Process Integration Analysis of an Industrial Hydrogen Production Process

The energy efficiency of an industrial hydrogen production process using steam methane reforming (SMR) combined with the water gas shift reaction (WGS) is analyzed using process integration techniques based on heat cascade calculation and pinch analysis with the aim of identifying potential measures to enhance the process performance. The challenge is to satisfy the high temperature heat demand of the SMR reaction by minimizing the consumption of natural gas to feed the combustion and to exploit at maximum the heat excess at low temperature by producing valuable steam or electricity or by performing cogeneration. By applying a systematic methodology based on energy-flow models, process integration techniques and a multi-objective optimization procedure, the process performances defined by the specific natural gas consumption and the specific steam or electricity production is optimized and analyzed for different operating conditions (i.e. air preheating, pre-reforming/reforming, WGS temperature) and process modification options like pre-reformer integration. Identified measures are to increase the production of exportable steam by consuming the entire waste heat and optimizing the steam production pressure level, and to reduce the natural gas consumption by adjusting process parameters. By these measures the performance can be varied between 0.53-0.59 kmol natural gas/kmol H2 for the specific total natural gas consumption and 1.8-3.7 kmol steam/kmol H2 for the specific steam production

Representation of Solid, Liquid, and Vapor phases of Binary Lennard Jones Mixtures using the SLV-EoS

The capability of the SLV-EoS, recently proposed by A. Yokozeki [1], of representing the phase diagrams for binary mixtures of Lennard-Jones (LJ) fluids has been investigated in this work. The SLV-EoS has been used for producing the phase diagrams of binary Lennard-Jones mixtures with diameter ratio σ11/σ22 ranging from 0.85 and 0.95, and well-depth ratio ɛ11/ɛ22 ranging from 0.625 and 1.6 at reduced pressure P*=Pσ11 3/ɛ11=0.002. The obtained phase diagrams have been compared with the corresponding results obtained by Monte-Carlo (MC) simulation [2-5]

Etude expérimentale des équilibres liquide-vapeur du système H2O-CO2-NOx-SOx sous pression

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New catalysts with low amounts of active phase for CPO processes

none7noneF. Basile; P. Arpentier; P. del Gallo; D. Gary; G. Fornasari; V. Rosetti; A. VaccariF. Basile; P. Arpentier; P. del Gallo; D. Gary; G. Fornasari; V. Rosetti; A. Vaccar