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Thomas Turek - One of the best experts on this subject based on the ideXlab platform.

  • Reactors for Fischer‐Tropsch Synthesis
    Chemical Engineering & Technology, 2008
    Co-Authors: Robert Guettel, Ulrich Kunz, Thomas Turek
    Abstract:

    The Fischer-Tropsch synthesis was discovered in Germany in the 1920s and has since been developed to industrial scale within a relatively short period of time. In the 21st century, the process is undergoing a renaissance, because an increasing fraction of liquid fuels will have to be produced from alternative raw materials like natural gas, coal or biomass in the future. On industrial scale, multitubular and bubble column reactors are used for this Highly Exothermic Reaction. Due to several disadvantages of both reactor systems, new concepts are presently investigated. For intensification of mass transfer properties of multiphase reactors, alternative catalyst geometries like honeycombs, structured packings or foams are discussed. High catalyst utilization and isothermal operating conditions can be achieved in microstructured reactors. Furthermore, several membrane reactor concepts are under investigation. After an introduction to historical development and state of the art of Fischer-Tropsch reactors, chances and challenges of new reactor technologies will be discussed.

Ulrich Quaade - One of the best experts on this subject based on the ideXlab platform.

  • Microfabricated high-temperature reactor for catalytic partial oxidation of methane
    Applied Catalysis A: General, 2005
    Co-Authors: Osnat Younes-Metzler, Jakob Svagin, Søren Jensen, Ulrich Quaade, Claus Hviid Christensen, Ole Hansen
    Abstract:

    A new setup using microfabricated silicon reactors for studying high-temperature partial oxidation Reactions is described in this paper. Methane oxidation is chosen as a test Reaction. The system is completely safe to operate due to the small size and the temperature is easy to control even for the Highly Exothermic Reaction. The activation energy obtained for full oxidation of methane on Pd/Al2O3 catalyst is similar to the values reported in the literature for the case of oxidized Pd particles. The simplicity of depositing the catalyst, bonding and mounting the microreactor, gives a fast, safe, and easy way for reliable catalyst screening in studying partial oxidation Reactions. ?? 2005 Elsevier B.V. All rights reserved.

Brian J. Marquardt - One of the best experts on this subject based on the ideXlab platform.

  • moffat swern oxidation of alcohols translating a batch Reaction to a continuous flow Reaction
    Journal of Flow Chemistry, 2015
    Co-Authors: Olav Bleie, Michael F. Roberto, Thomas I. Dearing, Charles W. Branham, Olav M Kvalheim, Brian J. Marquardt
    Abstract:

    The Moffatt-Swern oxidation (MSO) is a multistep, versatile, metal-free Reaction by which alcohols are transformed into aldehydes and ketones. Batch MSO requires low temperatures (−70 °C) due to a Highly Exothermic Reaction step that generates intermediates. This work shows that a rigorous investigation of the MSO in batch can be used as a stepping-stone to its implementation in a continuous-flow reactor (CFR). This work has two parts: the first part details the investigation of MSO in batch; the second covers the translation of the knowledge derived from batch to a CFR. The MSO batch Reaction was performed under cryogenic conditions with real-time process monitoring. The Reaction was monitored with Raman spectroscopy and could be tracked throughout the Reaction. All concentrations were validated using offline high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). Two configurations of the CFR were produced. Configuration 1 used the traditional batch methodology in...

  • Moffat-Swern Oxidation of Alcohols: Translating a Batch Reaction to a Continuous-Flow Reaction
    Journal of Flow Chemistry, 2015
    Co-Authors: Olav Bleie, Michael F. Roberto, Thomas I. Dearing, Charles W. Branham, Olav M Kvalheim, Brian J. Marquardt
    Abstract:

    The Moffatt-Swern oxidation (MSO) is a multistep, versatile, metal-free Reaction by which alcohols are transformed into aldehydes and ketones. Batch MSO requires low temperatures (−70 °C) due to a Highly Exothermic Reaction step that generates intermediates. This work shows that a rigorous investigation of the MSO in batch can be used as a stepping-stone to its implementation in a continuous-flow reactor (CFR). This work has two parts: the first part details the investigation of MSO in batch; the second covers the translation of the knowledge derived from batch to a CFR. The MSO batch Reaction was performed under cryogenic conditions with real-time process monitoring. The Reaction was monitored with Raman spectroscopy and could be tracked throughout the Reaction. All concentrations were validated using offline high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). Two configurations of the CFR were produced. Configuration 1 used the traditional batch methodology in terms of reagent addition and Reaction conditions. Configuration 2 used the information derived from the batch Reaction, changing the order of the reagent addition and increasing the temperature of the reactor. Real-time quantitative monitoring of chemical yield in the CFR was demonstrated via Raman spectroscopy and partial least squares (PLS) regression modeling. Reaction yield was accurately predicted every 15 s, reducing the need for chromatographic validation once the model was built. Configuration 2 was shown to perform comparably to configuration 1 at low temperature and far outperforming it at higher temperatures. Both CFR configurations performed significantly better than the batch setup in terms of temperature and yield, as was expected.

Robert Guettel - One of the best experts on this subject based on the ideXlab platform.

  • Reactors for Fischer‐Tropsch Synthesis
    Chemical Engineering & Technology, 2008
    Co-Authors: Robert Guettel, Ulrich Kunz, Thomas Turek
    Abstract:

    The Fischer-Tropsch synthesis was discovered in Germany in the 1920s and has since been developed to industrial scale within a relatively short period of time. In the 21st century, the process is undergoing a renaissance, because an increasing fraction of liquid fuels will have to be produced from alternative raw materials like natural gas, coal or biomass in the future. On industrial scale, multitubular and bubble column reactors are used for this Highly Exothermic Reaction. Due to several disadvantages of both reactor systems, new concepts are presently investigated. For intensification of mass transfer properties of multiphase reactors, alternative catalyst geometries like honeycombs, structured packings or foams are discussed. High catalyst utilization and isothermal operating conditions can be achieved in microstructured reactors. Furthermore, several membrane reactor concepts are under investigation. After an introduction to historical development and state of the art of Fischer-Tropsch reactors, chances and challenges of new reactor technologies will be discussed.

Mitra H Tabatabaei - One of the best experts on this subject based on the ideXlab platform.

  • cfd modeling of catalyst pellet for oxidative coupling of methane heat transfer and Reaction
    Particuology, 2013
    Co-Authors: Ramin Maghrebi, Nakisa Yaghobi, Siavash Seyednejadian, Mitra H Tabatabaei
    Abstract:

    Abstract This study deals with the phenomena occuring at single-pellet catalyst scale for the oxidative coupling of methane where heat transfer plays an important role. Computational fluid dynamics (CFD) is used for obtaining detailed rate and temperature profiles through the porous catalytic pellet where Reaction and diffusion compete. Intra-particle temperature and concentration gradients were taken into account by solving heat transfer coupled with continuity equations in the catalyst pellet. In heat transfer, the energy term due to Highly Exothermic Reaction was considered. Two external programs were successfully implemented into the CFD-code as kinetic and heat of Reaction terms. Simulation results showed that Reaction was favored at the beginning for the pellet, followed by diffusion predomination. The results of CFD simulation indicate that temperature variation within the catalyst pellet is