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Reactor Used (reactor + used)
Selected AbstractsUse of average value of Langmuir probe characteristic for characterization of pulsed dischargesCONTRIBUTIONS TO PLASMA PHYSICS, Issue 7 2003J. Bla Abstract Based on numerical calculations a new method has been developed, which enables plasma analysis from the average value of the Langmuir probe current measured in pulsed discharge. The application of this method for characterization of a planar reactor used for plasma enhanced chemical vapor deposition of TiN and (TiAl)N hard coatings is described as an example. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Microbial composition and structure of a multispecies biofilm from a trickle-bed reactor used for the removal of volatile aromatic hydrocarbons from a waste gasJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2004Dariusch Hekmat Abstract The microbial composition and structure of a multispecies biofilm of a laboratory-scale trickle-bed bioreactor for the treatment of waste gas was examined. The model pollutant was a volatile organic compound-mixture of polyalkylated benzenes called Solvesso 100®. Fluorescent in-situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) were applied. Two new Solvesso 100® -degrading Pseudomonas sp strains were isolated from the multispecies biofilm. Corresponding isolate-specific oligonucleotide probes were designed and applied successfully. A major finding was that the fraction of Solvesso 100® -degrading bacteria in the biofilm was low (about 3,6% during long-term operation). The majority of the active cells were saprophytes which utilized intermediates and cell lysis products. The measured fraction of extracellular polymeric substances of the mature biofilm was 89,93% of the total biomass. The CLSM examinations of a 3-days-old approx 10 µm thick biofilm revealed highly heterogeneous structures with distinguished three-dimensional matrix-enclosed microcolony bodies spread across the substratum surface. The 28-days-old 80,960 µm thick biofilm exhibited voids, cell-free channels, and pores of variable sizes. In both cases, an even distribution of active cells and pollutant-degrading bacteria throughout the biofilm cross-section as well as through the biofilm depth was observed. Copyright © 2003 Society of Chemical Industry [source] Fischer-Tropsch synthesis product grade optimization in a fluidized bed reactorAICHE JOURNAL, Issue 8 2006Fabiano A. N. Fernandes Abstract Fischer-Tropsch synthesis is an important chemical process for the production of liquid fuels and olefins. In recent years, the abundant availability of natural gas and the increasing demand of olefins, gasoline, diesel and waxes have led to a high interest in further developing this process. A mathematical model of a fluidized-bed reactor used for syngas polymerization was developed and the carbon monoxide polymerization was studied from a modeling point of view. Simulation results show that several parameters affect syngas conversion and carbon product distribution, such as operating pressure, superficial gas velocity, bed porosity, and syngas composition. Optimization of liquid hydrocarbon products was done and the best operating conditions for their production were found for an iron catalyst that produces hydrocarbon chains according to a dual mechanism theory. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source] Simulation of fine particle formation by precipitation using computational fluid dynamicsTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2000Damien Piton Abstract The 4-environment generalized micromixing (4-EGM) model is applied to describe turbulent mixing and precipitation of barium sulfate in a tubular reactor. The model is implemented in the commercial computational fluid dynamics (CFD) software Fluent. The CFD code is first used to solve for the hydrodynamic fields (velocity, turbulence kinetic energy, turbulent energy dissipation). The species concentrations and moments of the crystal size distribution (CSD) are then computed using user-defined transport equations. CFD simulations are performed for the tubular reactor used in an earlier experimental study of barium sulfate precipitation. The 4-EGM CFD results are shown to compare favourably to CFD results found using the presumed beta PDF model. The latter has previously been shown to yield good agreement with experimental data for the mean crystal size at the outlet of the tubular reactor. On a appliqué un modéle de micromélange généralisé à 4 environnements (4-EGM) afin de décrire le mélange turbulent et la précipitation du sulfate de baryum dans un réacteur tubulaire. Ce modéle a été implanté dans le logiciel de CFD commercial Fluent. Le programme de CFD est d'abord utilisé pour calculer les champs hydrodynamiques (vitesse, énergie cinétique de turbulence, dissipation d'énergie turbulente). Les concentrations d'espéces et les moments de la distribution de taille des cristaux (CSD) sont ensuite calculés par ordinateur à l'aide des équations de transport définies par l'usager. Des simulations de CFD sont réalisées pour le réacteur tubulaire utilisé dans une étude expérimentale antérieure de la précipitation du sulfate de baryum. On montre que les prédictions du 4-EGM se comparent favorablement à celles du modéle béta PDF. II a été montré antérieurement que ce dernier présentait un bon accord avec les donnés expérimentales pour la taille moyenne des cristaux à la sortie du récteur tubulaire. [source] Selectivity effects on series reactions by reactant storage and PSA operationAICHE JOURNAL, Issue 11 2000Adriaan J. Kodde This work evaluates adsorptive reactors used to improve the operation of a sequential reaction scheme, , for the total removal of A from a stream with an excess of B. In the adsorptive-reactor concept, the reactor is filled with a physical mixture of catalyst and an adsorbent, the latter being thermodynamically selective toward primary reactant A. In this case, the sorbent is periodically regenerated using the principles of pressure swing adsorption and purged with secondary reactant D. This concept is restricted to low temperatures to have sufficient adsorption capacity. Improved reaction selectivity arises from the accumulation of A in the unit. The reaction of A maximizes the driving force for regeneration and thus accelerates the regeneration half-cycle. The adsorptive reactor is compared to a conventional plug-flow reactor (PFR) and to PSA and PFR units in series. Reaction selectivity improved and pure B recovered over these alternative reactors under realistic conditions. The volume-based productivity is lower than that of PFR, but higher than that of PSA. The purge-gas flow rate can be manipulated to balance the sorption flux and reaction rate, thereby maximizing the conversion of A. The influence of differences in sorption kinetics is discussed and the required sorbent characteristics are identified. [source] Reply to: "Testing the Hypothesis: Comments on Plasma Polymerization of Acrylic Acid Revisited"PLASMA PROCESSES AND POLYMERS, Issue 5 2010Dirk Hegemann Abstract We reply to the discussions started by Rob Short and David Steele concerning the use of a macroscopic approach to examine the plasma polymerization of acrylic acid. Therefore, we analyze data of mass deposition rates versus the reaction parameter W/F using Arrhenius-type plots, which were recorded in different plasma reactors used by Short et al. and our group. [source] | ||||||||||