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991.
Dr. Katja Neubauer Udo Lubenau Christine Hecker Prof. Dr. Bernhard Lücke Dr. Dietmar Paschek Dr. Sebastian Wohlrab 《化学,工程师,技术》2013,85(5):713-722
The depletion of higher alkanes from methane is a key aspect during the conditioning of natural gases or accompanying gases. Membrane technologies could be used as alternative to energy and cost intensive purifications. Against this background the influence of membrane geometry, composition of the gas mixture as well as temperature and pressure was investigated in separation experiments for methane/n‐butane mixtures using MFI membranes. 相似文献
992.
Highly resistive dusts show markedly non‐ohmic properties. The property known as specific resistivity is strongly dependent on the dust layer thickness and on the polarity of the high voltage. The current transport occurs by excess charges of both polarities, which leads to high space charge densities and induces strong electrostatic fields. The theory of electrets provides a consistent explanation of the phenomena observed so far. To investigate the electrical properties, highly resistive dusts were exposed to an electrical field with interfering corona discharges within a tip‐plate arrangement. 相似文献
993.
Dr. Nikolay B. Anikin Prof. Dr. Rainer Suntz Prof. Dr.‐Ing. Henning Bockhorn 《化学,工程师,技术》2013,85(5):696-704
A recently developed and patented fast tomographic reconstruction system has been applied to detect two‐dimensional distributions of the OH* chemiluminescence in laminar and turbulent flames. This could be achieved by the arrangement at exposure times down to 100 – 200 μs at a spatial resolution of < 1 – 2 mm, even though the concentration of OH* in flames is in the order of some ppb and, therefore, extremely small. Among other things the results provide important information regarding the determination of the heat release rate in flames to predict unstable operating points of gas turbines. 相似文献
994.
In times of the German energy transition (“Energiewende”) chemical storage technologies achieve an increasing interest because only with their help the energy of the excess electricity from wind‐ and solar plants can be stored in huge quantities in form of hydrocarbons. The hydrogen generated by water electrolysis can be converted with carbon dioxide to hydrocarbons. In addition, pure CO2 must be available at a reasonable price. For this CO2 supply a sustainable concept is presented. 相似文献
995.
Tobias Günter Dr. Maria Casapu Dr. Dmitry Doronkin Dr. Stefan Mangold Vanessa Trouillet Timo Augenstein Prof. Jan‐Dierk Grunwaldt 《化学,工程师,技术》2013,85(5):632-641
The potential of the natural chabazite for the selective catalytic reduction (SCR) of NOx with NH3 is evaluated in the present work. Activity tests were performed under technically relevant reaction and temperature conditions for the fresh and hydrothermally aged catalysts. The natural chabazite before and after alkaline removal as well as after iron and copper addition were compared. The structural as well as surface and bulk properties were elucidated by a variety of complementary characterization techniques, i.e. XRD, XPS, EPR, BET, NH3‐TPD, ex situ and in situ XAS. The results indicate that an important facet for using the natural chabazite for the standard and fast SCR reactions is the removal of alkaline metals, which at the same time also leads to a partial change of the structure and the size of the iron‐containing particles. The performance and especially the hydrothermal stability can be further improved by copper addition. 相似文献
996.
Dr. Daniel Peitz Dr. Andreas M. Bernhard Dr. Max Mehring Martin Elsener Dr. Oliver Kröcher 《化学,工程师,技术》2013,85(5):625-631
In order to reduce the NOx concentration in car exhausts usually the selective catalytic reduction with ammonia is used. However, to avoid the transport of ammonia in vehicles urea is applied as NH3 precursor. Controlled urea decomposition before the injection into the exhaust gas system itself may be accomplished by the use of a separate reactor. Urea decomposition to ammonia in the liquid phase under pressure in a heated reactor was compared to its decomposition in the gas phase. In the liquid phase, higher conversion rates relative to the reactor volume were realized than in the gas phase. Catalysts which showed high activity in the gas phase influenced the decomposition in the liquid phase only slightly. 相似文献
997.
Looking at exhaust‐gas after‐treatment systems in its entirety leads to further improvement of emission control devices and to the accomplishment of future challenges such as lower legislative emission limits, new fuels, and more efficient engine concepts. This article provides an overview on the state‐of‐the art mobile exhaust‐gas after‐treatment devices. Current and future challenges are discussed in the light of present approaches such as hierarchical modeling reaching from DFT computations of molecular processes to CFD simulation of entire lines of exhaust‐gas cleaning devices, close‐to‐reality emission control test benches and aging procedures, on‐board diagnostics, and catalyst characterization at operating conditions and preferentially all length scales. In future, knowledge‐based robot‐controlled preparation and dynamic models coupled with information from real operation will significantly support research and development. 相似文献
998.
Dr. Andrea Rentmeister 《化学,工程师,技术》2013,85(6):818-825
Degradation of cellulose represents a key step for efficient generation of biofuels such as ethanol or butanol from non‐food crops. Several strategies aim to improve the performance of cellulases in order to make the overall process more cost‐efficient. In one strategy, novel arrangements of cellulases are developed. The resulting so‐called designer cellulosomes might allow equipping fermenting hosts with sufficient cellulase activity to grow on cellulose as sole carbon source and, thus, enable consolidated bioprocessing. Other strategies aim to engineer cellulases with higher thermostability and activity to make cellulose hydrolysis more efficient. Current developments in the field of cellulose engineering are summarized and achievements as well as limitations are highlighted. 相似文献
999.
Dr. Steffen Waglöhner Dr. Dirk Reichert Prof. Henning Bockhorn Prof. Sven Kureti 《化学,工程师,技术》2013,85(5):686-695
Three commercial carbon black samples as well as self‐made C3H6 soot were investigated for their reactivity in the oxidation on an α‐Fe2O3 catalyst. These studies were performed by temperature programmed oxidation (TPO) using a packed bed. For reference purposes, TPO studies in the absence of the catalyst were made as well. The carbon black samples were characterized towards the content of C, H, N and O as well as higher heating value, specific surface area, moisture and volatile matter and were deemed to be suitable model substances for diesel soot of different maturity. The correlation of these physico‐chemical properties with the kinetics in catalytic TPO indicated that the soot oxidation on Fe2O3 is significantly affected by the initial number of surface oxygen compounds of the soot. The decomposition of these surface species causes the formation of active carbon sites, which are supposed to accelerate the soot oxidation. 相似文献
1000.