CFD Modeling of the High Efficiency Rotor Separator in Cement Grinding Circuit

2013 ◽  
pp. 365-372
Author(s):  
Guizani Rim ◽  
Mokni Inès ◽  
Mhiri Hatem ◽  
Philippe Bournot
Keyword(s):  
High Efficiency ◽  
Cfd Modeling ◽  
Cement Grinding

One High Efficiency Production Line of Clinker and Slag Grinding Separately by Roller Mill in Cement Industry

2008 ◽  
Vol 58 ◽  
pp. 83-89
Author(s):  
Ning Chang Liu ◽  
Zhao Feng Li
Keyword(s):  
Energy Consumption ◽  
High Efficiency ◽  
High Energy ◽  
Cement Industry ◽  
Grinding Process ◽  
Roller Mill ◽  
Low Efficiency ◽  
Cement Grinding ◽  
Grinding System ◽  
High Energy Consumption

In cement industry, many grinding up systems are on operating now. The tradition process of tube mill grinding system is high energy consumption, so it’s low efficiency, especially in the final cement grinding process. The value and advantage of slag is recognized more and more, but it’s difficult to be grinded up. Furthermore, the disadvantage and shortages to grind up clinker compounded with slag to produce cement are obvious and adopted. The best process is to grind up slag, clinker separately. Then, these two kinds of powder are compounded by a mixer. Hereby, it introduces a design of the process to grind up clinker, slag by one roller mill.

Development of Direct Carbonate Fuel Cell Systems for Achieving Ultra High Efficiency

2010 ◽  
Author(s):  
Hossein Ghezel-Ayagh ◽  
Joseph McInerney ◽  
Ramki Venkataraman ◽  
Mohammad Farooque ◽  
Robert Sanderson
Keyword(s):  
Fuel Cell ◽  
High Efficiency ◽  
Cfd Modeling ◽  
Fuel Cell Stack ◽  
In Series ◽  
Parametric Studies ◽  
Second Tier ◽  
System Configurations ◽  
Carbonate Fuel Cell ◽  
Very High

FuelCell Energy, Inc (FCE) has developed products based on its Direct FuelCell® (DFC®) technology with efficiencies near 50 percent based on lower heating value of (LHV) of natural gas. DFC is an internally reformed molten carbonate fuel cell (MCFC) which operates in the 550–700 C range. The combination of the internal reforming of methane and atmospheric pressure and moderately high temperature of operation has resulted in very simple power plant system configurations. Recently, FCE has developed system concepts to further increase the net electric efficiency to beyond 60% efficiency in subMW and MW class power plants. One of these system concepts is the arrangement of the fuel cell stacks in series for very high utilization of fuel in the stacks. Although, in principle, the concept of fuel cell stacks in series is very simple, the implementation of the concept in the actual hardware poses challenges requiring innovative solutions. These challenges include concerns with thermo-mechanical issues, flow and utilization patterns within the fuel cell stacks, and management of the pressure balance between the anode-and-cathode. To address, these issues, various analytical tools including system-level modeling and simulation and Computational Fluid Dynamics (CFD) were utilized. FCE has developed a comprehensive fuel cell stack operation simulation model including hydrodynamics, kinetics, electro-chemical, and heat transfer mechanisms to investigate and optimize the design for performance as well as endurance. Various system configurations were developed which included methods for fueling the second tier stacks in the series. System simulation studies using first principle mass and energy conversation laws were performed. Parametric studies were completed. Subsequent to the system modeling results, the fuel cell stacks operations were analyzed using the Comprehensive Stack Simulation model. The CFD modeling of the fuel cell stacks were performed in support of the system simulation parametric studies. The results of the CFD modeling provided insight to the thermal and flow profiles of both first and second tier stacks in series. The net outcome of the investigation was the design of the system which met the goals of ultra high efficiency and yet complied with the thermo-mechanical requirements of the fuel cell stack components. In this paper, FCE will describe various system options for the very high efficiency systems, the issues related to the design, and the practical solutions to overcome the issues.

scholarly journals Development of Pilot-Scale CO2 Methanation Using Pellet-Type Catalysts for CO2 Recycling in Sewage Treatment Plants and Its Validation through Computational Fluid Dynamics (CFD) Modeling

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1005
Author(s):  
Jeongyoon Ahn ◽  
Heysuk Kim ◽  
Yeonhee Ro ◽  
Jintae Kim ◽  
Woojin Chung ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Efficiency ◽  
Sewage Treatment ◽  
Exothermic Reaction ◽  
Pilot Scale ◽  
Cfd Modeling ◽  
Co2 Methanation ◽  
Computational Fluid Dynamics Cfd ◽  
Methanation Catalyst

In this study, a pilot-scale reactor was designed and compared using computational fluid dynamics (CFD) for a high-efficiency CO2 methanation reaction. The trends of the CO2 methanation catalyst efficiency at a pilot or industrial scale could be lower than those measured at the laboratory scale, owing to the flow of fluid characteristics. Therefore, the CO2 methanation reactor was designed based on the results of the CFD analysis to minimize the above phenomenon. Ni–Ce–Zr was used to manufacture a CO2 methanation catalyst in the form of pellets. The catalyst successfully produced about 43.3 Nm3/d of methane from the reactor. This result shows that CO2 methanation, which is known as an exothermic reaction, was stable at the pilot scale. It is believed that the self-supply of energy will be possible when this CO2 methanation technology is applied to industrial processes generating large amounts of CO2 and H2 from by-product gases.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

Imaging and diffraction modes in Scanning Transmission Electron Microscopy

1986 ◽  
Vol 44 ◽  
pp. 684-687
Author(s):  
J. M. Cowley ◽  
R. Glaisher ◽  
J. A. Lin ◽  
H.-J. Ou
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
High Efficiency ◽  
Fiber Optic ◽  
Image Intensifier ◽  
Detector System ◽  
Detector Plane ◽  
Secondary Electrons ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Special Detector

Some of the most important applications of STEM depend on the variety of imaging and diffraction made possible by the versatility of the detector system and the serial nature, of the image acquisition. A special detector system, previously described, has been added to our STEM instrument to allow us to take full advantage of this versatility. In this, the diffraction pattern in the detector plane may be formed on either of two phosphor screens, one with P47 (very fast) phosphor and the other with P20 (high efficiency) phosphor. The light from the phosphor is conveyed through a fiber-optic rod to an image intensifier and TV system and may be photographed, recorded on videotape, or stored digitally on a frame store. The P47 screen has a hole through it to allow electrons to enter a Gatan EELS spectrometer. Recently a modified SEM detector has been added so that high resolution (10Å) imaging with secondary electrons may be used in conjunction with other modes.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

The use of high-resolution FESEM to study solid-state phase transformations and reactions

1994 ◽  
Vol 52 ◽  
pp. 1028-1029
Author(s):  
P. G. Kotula ◽  
D. D. Erickson ◽  
C. B. Carter
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Phase Transformations ◽  
High Efficiency ◽  
Sol Gel ◽  
Quantitative Information ◽  
Solid State Reactions ◽  
Critical Dimensions ◽  
Backscattered Electrons ◽  
Backscattered Electron

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

Interlayer confinement synthesis of Ir nanodots/dual carbon as an electrocatalyst for overall water splitting

2020 ◽  
Author(s):  
Yaru Li ◽  
Yu-Quan Zhu ◽  
Weili Xin ◽  
Song Hong ◽  
Xiaoying Zhao ◽  
...  
Keyword(s):  
Water Splitting ◽  
Noble Metal ◽  
High Efficiency ◽  
Overall Water Splitting ◽  
Highly Dispersed

Rationally designing low-content and high-efficiency noble metal nanodots offers opportunities to enhance electrocatalytic performances for water splitting. However, the preparation of highly dispersed nanodots electrocatalysts remains a challenge. Herein, we...

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