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CFd based extraction column design-Chances and challenges

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Chinese Journal of Chemical Engineering 2016年第2期24卷 259-263页

作者： Mark W.Hlawitschka Menwer M.Attarakilh Samer S.Alzyod Hans-Jorg Bart Chair of Separation Science and Technology POB 3049TU KaiserslauternKaiserslautern 67653Germany Center for Computational and Mathematical Modelling(CM2) TU KaiserslauternKaiserslautern 67653Germany University of Jordan Department of Chemical Engineering11942 AmmanJordan

This paper shows that one-dimensional （I-d） [and three-dimensional （3-d） computational fluid dynamics （CFd）] simulations can replace the state-of-the-art usage of pseudo-homogeneous dispersion or back mixing models. This is based on standardized lab-scale cell experiments for the determination of droplet rise, breakage, coalescence and mass transfer parameters in addition to a limited number of additional mini-plant experiments with original fluids. Alternatively, the hydrodynamic parameters can also be derived using more sophisticated 3- d CFd simulations. Computational 1-d modeling served as a basis to replace pilot-plant experiments in any column geometry. The combination of 3-d CFd simulations with droplet population balance models （dPBM） increased the accuracy of the hydrodynamic simulations and gave information about the local droplet size. The high computational costs can be reduced by open source CFd codes when using a flexible mesh generation. First combined simulations using a three way coupled CFd/dPBM/mass-transfer solver pave the way for a safer design of industrial-sized columns, where no correlations are available.

关键词： CFd dPBM Column design

Isolation and Sorption Behavior of Humic Acid from Zhongdian Peat of Yunnan Province,China

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Pedosphere 2009年第5期19卷 606-614页

作者： NING Ping WANG Hong-Bin PAN Bo H.-J. BART YANG Min College of Environmental Science and Engineering Kunming University of Science and Technology Kunming 650093 （China） Lehrstuhl fiir Thermisehe Verfahrenstechnik University of Kaiserslautern Kaiserslautern D-67653 （Germany）

The Zhongdian swamp meadow in Zhongdian,China is well known as "Shangri-la",where the peat has never been studied for its potential to interact with *** acid(HA) was extracted from Zhongdian peat using two methods,namely sodium pyrophosphate extraction(SPE) and dilute base extraction(dBE),and characterized for its functional groups and sorption *** HAs extracted by both methods contained several active functional groups and had large external specific surface *** adsorption mechanism of methylene blue onto HAs was interpreted as Langmuir ***-HA showed higher sorption capacity because of its larger specific surface area,whereas the extraction yield of dBE-HA was twice that of *** modeling indicated that the sorption of methylene blue was a two-component first order *** component with the higher rate constant also showed higher sorption *** pH effect was observed for methylene blue sorption on HA in our experimental design,and the sorption decreased as the temperature increased.

关键词： extraction kinetics modeling Langmuir methylene blue Shangri-la

Equilibrium Segregation to Free Surface:Kinet ics and Experiment

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Chinese Physics Letters 1999年第5期16卷 364-366页

作者： CAO Ze-xian Ralf Mueller WANG En-ge NIE Yu-xin State Key Laboratory for Surface Physics Institute of PhysicsChinese Academy of SciencesBeijing 100080 department of Physics University Kaiserslautern67653 KaiserslauternGermany

Fick's first law is modified with an additional term df(x)/dx to describe the segregation phenomenon,f(x)is a local,analytical function related to the depth profile at *** thus can be determined experimentally by depth profiling *** starting in an initially homogeneous solid is described by an inhomogeneous diffusion equation on the half-infinite *** with and without formation of overlayer suggests different boundary *** solution for the Ansatz f(x)=as exp(-x/d_(s))is in perfect agreement with experimental results on sulphur segregation to the surface of *** from the detailed kinetics,activation energy can be inferred from the surface concentration evolution under different *** sulphur segregation in titanium,E_(act)=718 meV/atom.

关键词： technique. titanium sulphur

Phosphate removal from wastewater by model-La(Ⅲ)zeolite adsorbents

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Journal of Environmental Sciences 2008年第6期20卷 670-674页

作者： NING Ping BART Hans-Jorg LI Bing LU Xiwu ZHANG Yong department of Environmental Science and Engineering Kunming University of Science and Technology Kunming 650093 China Lehrsmhl für Thermische Verfahrenstechnik TU Kaiserslautern D-67653 Kaiserslautern Germany department of Environmental Engineering Southeast University Nanjing 210096 China

Phosphorus is one of the primary nutrients which leads to eutrophication and accelerates aging process in enclosed water bodies. Because of the poor phosphorus selectivity of other adsorbents, the novel La（Ⅲ）-modified zeolite adsorbent （LZA） was prepared by modifying 90 nm zeolite with lanthanide to selectively remove phosphate in the presence of various omnipresent anions, such as sulfates, bicarbonates, and chlorides. Through batch and fixed bed operation, the following optimum conditions were obtained： concentration of lanthanum chloride solution 0.05 mol/L; solid/liquor ratio 1/25; pH 10; calcination temperature 550℃; time 1 h. The value of the Freundlich model constants Kf and 1/n were found to be 16.76 mg/L and 0.2209, respectively. In addition, when calculated at pH 6.0, distribution coefficient Kd could be as high as 36.6. Furthermore, in the alkaline pH range, solution of 0.8 mol/L NaCl was used to regenerate the saturated LZA, which could reach the high regeneration efficiency as high as 100%. Because of the good selectivity and regenerability of LZA, it might serve as a potential way for advanced phosphate removal from the sewage containing other anions.

关键词： phosphate adsorption zeolite regeneration distribution coefficient

Heat Transfer and Hydrodynamics in Annular Chromatography: CFd-Simulation and Experiments

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Journal of Thermal Science 2000年第2期9卷 129-134页

作者： Hans－JoergBart JorgBrozio 等 UniversitaetKaisersautern LehrstuhifuerThermischeVerfachrenstechnikPostfach3049D－67653KaiserslauternGermanyE－amil：bart@mv.uni－kl.de UniversitaetKaisersautern LehrstuhifuerThermischeVerfachrenstech

Continuous annular chromatography(CAC) is a separation process for multicomponent liquid mixtures. The performance of the apparatus can be seriously decreased by temperature gradients inside the adsorbent bed. It is shown, that the temperature gradients can be significantly reduced by a pre-heating of the entering liquid in the apparatus itself. Heat transfer and hydrodynamics in the porous media are described by two different modelling approaches. Both are based on a pseudo-homogeneous model for heat transfer with temperature dependent fluid viscosities. The first model considers one-dimensional fluid now and two-dimensional heat transfer. The second, more rigorous one is a three-dimensional model for heat transfer and hydrodynamics. The simulation results obtained with both models are in good agreement with experimental results. The experiments have been performed with glass beads as the stationary phase and water as the liquid phase under different boundary conditions. The temparature profiles inside the packed bed have been measured with thermocouples.

关键词： porous media numerical heat transfer chromatography computational fluid dynamics.

Removal of P4, PH3 and H2S from Yellow Phosphoric Tail Gas by a Catalytic Oxidation Process

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Engineering Sciences 2004年第4期 20-27页

作者： Hans-Jrg Bart d-67653 kaiserslautern Germany Lehrstuhl für Thermische Verfahrenstechnik University kaiserslautern

Yellow phosphorus tail gas is a resource used to produce bulk chemicals, such as formates, oxalates, and methanol after its pretreatment and purification. In this study, catalytic oxidation of phosphorus and hydrogen sulfide in yellow phosphorus tail gas was investigated on an ordinary activated carbon (OAC) and a home made catalyst KU2. The adsorption characteristics of phosphorus and hydrogen sulfide on the catalysts were studied in a fixed-bed system at different temperatures between 20℃ and 140℃ at atmospheric pressure. Both KU2 and OAC are proved to be effective catalysts in the catalytic oxidation process (COP) for H 2S and PH 3 removal. Purification efficiency increased with the increase of temperature and oxygen concentration in yellow phosphorus tail gases. Under optimized operation conditions, the product gases with a content of hydrogen sulfided total phosphorusd by using the COP process. deactivated catalysts could be restored to the original activated state, even after several regenerations. A mathematical model was developed to simulate the experimental results and the mass transport coefficient from the experiment was evaluated. Good agreement between the experimental breakthrough curves and the model predictions was observed.

关键词： H2S P4 PH3 catalytic oxidation fixed bed adsorber activated charcoal

Simulation of size effects by a phase field model for fracture

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Theoretical & Applied Mechanics Letters 2014年第5期4卷 50-53页

作者： Charlotte Kuhn Ralf Müller Computational Mechanics University of Kaiserslautern67653 KaiserslauternGermany Institute of Applied Mechanics University of Kaiserslautern67653 KaiserslauternGermany

In phase field fracture models the value of the order parameter distin- guishes between broken and undamaged material. At crack faces the order param- eter interpolates smoothly between these two states of the material, which can be regarded as phases. The crack evolution follows implicitly from the time inte- gration of an evolution equation of the order parameter, which is coupled to the mechanical field equations. Among other phenomena phase field fracture mod- els are able to reproduce crack nucleation in initially sound materials. For a 1d setting it has been shown that crack nucleation is triggered by the loss of stability of the unfractured, spatially homogeneous solution, and that the stability point depends on the size of the considered structure. This work numerically investi- gates to which extend size effects are reproduced by the 2d phase field model. Exemplarily, a finite element study of the hole size effect is performed and the simulation results are compared to exnerimental data.

关键词： phase field model fracture mechanics size effects stability finite elementmethod

Lichen species dominance and the resulting photosynthetic behavior of Sonoran desert soil crust types(Baja California,Mexico)

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Ecological Processes 2013年第1期2卷 64-72页

作者： Burkhard Büdel Mercedes Vivas Otto L Lange Plant Ecology and Systematics Biology DepartmentUniversity of KaiserslauternP.O.Box 3049D-67653KaiserslauternGermany department of Plant Science Faculty of PharmacyUniversidad Complutense de Madrid Plaza Ramóny Cajal28040MadridSpain Julius-von-Sachs-Institut für Biowissenschaften University of WürzburgJulius-von-Sachs-Platz 3D-97082WürzburgGermany.

Introduction:Lichen dominated biological soil crusts(BSCs)occur over large areas in the Sonoran desert of the southwestern USA and northwest *** Baja California BSCs show a distinct patchiness and several types can be *** chlorolichen-and two cyanolichen-dominated BSCs were *** hypothesize that patchiness and the resulting domination of certain functional lichen groups will result in patchiness of photosynthetic CO_(2)-uptake related to environmental factors as ***:Four different soil crust samples were placed in cuvettes and their CO_(2) exchange was recorded in an open system with an infrared gas *** blown over the BSCs had a controlled CO_(2) content of 350 *** cuvettes were operated in *** CO2 exchange was continually recorded throughout the ***:Besides the dominating chlorolichens Psora decipiens and Placidium squamulosum and the cyanolichens Peltula patellata and ***,several other lichen species and 12 cyanobacterial species were found in the biological soil crusts *** chlorolichen BSCs already gained positive net photosynthesis with high air humidity alone,while the cyanolichen types did not,but showed smaller CO_(2)-uptake depression after water *** specific net photosynthesis responses to mode of hydration and to crust water content seem to correlate with precipitation characteristics of their ***:Species specific photosynthetic performance related to activation of respiration and net photosynthesis as well as to crust water content help to explain niche occupation and species composition of *** functional types have to be considered when they have a patchy distribution.

关键词： Biological soil crust Lichens Cyanobacteria Photosy

Chirality and Negative Refraction without Absorption in the Optical domain Using Electromagnetically Induced Transparency

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Chirality and Negative Refraction without Absorption in the ...