scholarly journals Separation Process of Fine Coals by Ultrasonic Vibration Gas-Solid Fluidized Bed

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Shuai Wang ◽  
Yaqun He ◽  
Hua Wei ◽  
Weining Xie
Keyword(s):  
Fluidized Bed ◽  
Ultrasonic Vibration ◽  
Separation Process ◽  
Organic Sulfur ◽  
Combustible Material ◽  
Surface Distribution ◽  
Maximum Value ◽  
Distribution Of Elements ◽  
Heavy Product ◽  
Technological Methods

Ultrasonic vibration gas-solid fluidized bed was proposed and introduced to separate fine coals (0.5–0.125 mm fraction). Several technological methods such as XRF, XRD, XPS, and EPMA were used to study the composition of heavy products to evaluate the separation effect. Results show that the ultrasonic vibration force field strengthens the particle separation process based on density when the vibration frequency is 35 kHz and the fluidization number is 1.8. The ash difference between the light and heavy products and the recovery of combustible material obtain the maximum values of 47.30% and 89.59%, respectively. The sulfur content of the heavy product reaches the maximum value of 6.78%. Chemical state analysis of sulfur shows that organic sulfur (-C-S-), sulfate-sulfur (-SO4), and pyrite-sulfur (-S2) are confirmed in the original coal and heavy product. Organic sulfur (-C-S-) is mainly concentrated in the light product, and pyrite-sulfur (-S2) is significantly enriched in the heavy product. The element composition, phase composition, backscatter imagery, and surface distribution of elements for heavy product show concentration of high-density minerals including pyrite, quartz, and kaolinite. Some harmful elements such as F, Pb, and As are also concentrated in the heavy product.

scholarly journals Advanced test of the model stellar atmospheres: the nature of the light variability of magnetic chemically peculiar stars

2008 ◽  
Vol 4 (S252) ◽  
pp. 347-348
Author(s):  
J. Krtička ◽  
Z. Mikulášek ◽  
J. Zverko ◽  
J. Žižňovský ◽  
P. Zvěřina
Keyword(s):  
Chemical Elements ◽  
Horizontal Distribution ◽  
Stellar Atmospheres ◽  
Silicon Iron ◽  
Surface Distribution ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Distribution Of Elements ◽  
Chemically Peculiar Stars ◽  
Light Variability

AbstractThe magnetic chemically peculiar stars exhibit both inhomogeneous horizontal distribution of chemical elements on their surfaces and the light variability. We show that the observed light variability of these stars can be successfully simulated using models of their stellar atmospheres and adopting the observed surface distribution of elements. The most important elements that influence the light variability are silicon, iron, and helium.

scholarly journals Doppler Images of Rapidly Rotating Ap Stars

1988 ◽  
Vol 132 ◽  
pp. 199-204
Author(s):  
Artie P. Hatzes
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Stellar Surface ◽  
Surface Distribution ◽  
Distribution Of Elements ◽  
Local Equivalent ◽  
Field Geometry ◽  
A New Technique ◽  
Ap Stars

The magnetic Ap stars are characterized by the presence of large magnetic fields which undergo periodic variations. These magnetic field variations are accompanied by spectral variations caused by the inhomogeneous distribution of elements on the stellar surface. It is believed that the magnetic field plays an important role in determining this distribution. Accurate maps of the surface distribution of elements would provide valuable probes as to the field geometry as well as provide clues to the role of the magnetic fields in the atmospheres of these stars. We have developed a new technique for mapping the local equivalent width on a stellar surface from the observed spectral line variations.

scholarly journals Effect of Bed Particle Size on Thermal Performance of a Directly-Irradiated Fluidized Bed Gas Heater

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 967
Author(s):  
Sae Han Park ◽  
Chae Eun Yeo ◽  
Min Ji Lee ◽  
Sung Won Kim
Keyword(s):  
Particle Size ◽  
Fluidized Bed ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Gas Velocity ◽  
Bubble Behavior ◽  
Heat Transfer Characteristics ◽  
Maximum Value ◽  
Solar Thermal Collector ◽  
Sic Particle

There is a growing interest in a fluidized bed particle receiver that directly irradiates sunlight to particles in the fluidized bed as a solar thermal collector for heating. Thermal performance of directly-irradiated fluidized bed gas heater is strongly affected by the physical properties of the particles. The effect of SiC particle size on heat transfer characteristics in the solar fluidized bed gas heater (50 mm-ID × 100 mm high) has been determined. The outlet gas temperatures showed a maximum value with increasing gas velocity due to the particles motion by bubble behavior in the bed, and the maximum values were found at 3.6 times of Umf for fine SiC and less than 2.0 times of Umf for coarse SiC. Heat absorption from the receiver increased with increasing gas velocity, showing with maximum 18 W for the fine SiC and 23 W for the coarse SiC at 4.5 times of Umf. The thermal efficiency of the receiver increased with increasing gas velocity, but was affected by the content of finer particles. The maximum thermal efficiency of the receiver was 14% for fine SiC and 20% for coarse SiC within the experimental range, but showing higher for the fine SiC at the same gas velocity. A design consideration was proposed to improve the thermal efficiency of the system.

Dispersion of hydroxyapatite nanoparticles in solution and in polycaprolactone composite scaffolds

2016 ◽  
Vol 4 (3) ◽  
pp. 409-421 ◽  
Author(s):  
Chandhi S. Goonasekera ◽  
Kevin S. Jack ◽  
Justin J. Cooper-White ◽  
Lisbeth Grøndahl
Keyword(s):  
Phase Separation ◽  
Separation Process ◽  
Structure Property ◽  
Hydroxyapatite Nanoparticles ◽  
Composite Scaffolds ◽  
Surface Distribution ◽  
Solvent Interaction ◽  
Phase Separation Process ◽  
Nanocomposite Scaffolds ◽  
Property Performance

Structure–property–performance in TIPS fabricated nanocomposite scaffolds: influence of polymer–solvent interaction and phase-separation process on the dispersion and surface distribution of particles.

Particle pressures generated around bubbles in gas-fluidized beds

2002 ◽  
Vol 455 ◽  
pp. 103-127 ◽  
Author(s):  
KHURRAM RAHMAN ◽  
CHARLES S. CAMPBELL
Keyword(s):  
Fluidized Bed ◽  
Bubble Size ◽  
Fluidized Beds ◽  
Gas Flow ◽  
Solid Particles ◽  
Particle Phase ◽  
Fluid Mixture ◽  
Maximum Value ◽  
Particle Pressure ◽  
Gas Fluidized Beds

The particle pressure is the surface force in a particle/fluid mixture that is exerted solely by the particle phase. This paper presents measurements of the particle pressure on the faces of a two-dimensional gas-fluidized bed and gives insight into the mechanisms by which bubbles generate particle pressure. The particle pressure is measured by a specially designed ‘particle pressure transducer’. The results show that, around single bubbles, the most significant particle pressures are generated below and to the sides of the bubble and that these particle pressures steadily increase and reach a maximum value at bubble eruption. The dominant mechanism appears to be defluidization of material in the particle phase that results from the bubble attracting fluidizing gas away from the surrounding material; the surrounding material is no longer supported by the gas flow and can only be supported across interparticle contacts which results in the observed particle pressures. The contribution of particle motion to particle pressure generation is insignificant.The magnitude of the particle pressure below a single bubble in a gas-fluidized bed depends on the bubble size and the density of the solid particles, as might be expected as the amount of gas attracted by the bubble should increase with bubble size and because the weight of defluidized material depends on the density of the solid material. A simple scaling of these quantities is suggested that is otherwise independent of the bed material.In freely bubbling gas-fluidized beds the particle pressures generated behave differently. Overall they are smaller in magnitude and reach their maximum value soon after the bubble passes instead of at eruption. In this situation, it appears that the bubbles interact with one another in such a way that the de uidization effect below a leading bubble is largely counteracted by refluidizing gas exiting the roof of trailing bubbles.

scholarly journals Carbon Shale Combustion in the Fluidized Bed Reactor

2014 ◽  
Vol 16 (2) ◽  
pp. 74-76 ◽  
Author(s):  
Małgorzata Olek ◽  
Stanisław Kandefer ◽  
Wiesław Kaniowski ◽  
Witold Żukowski ◽  
Jerzy Baron
Keyword(s):  
Fluidized Bed ◽  
Flue Gas ◽  
Combustion Process ◽  
Fluidized Bed Reactor ◽  
Ash Content ◽  
Conversion Degree ◽  
Hard Coal ◽  
Combustible Material ◽  
High Quality ◽  
Bubbling Fluidized Bed

Abstract The purpose of this article is to present the possibilities of coal shale combustion in furnaces with bubbling fluidized bed. Coal shale can be autothermally combusted in the fluidized bed, despite the low calorie value and high ash content of fuel. Established concentrations of CO (500 ppm) and VOC (30 mg/m3) have indicated a high conversion degree of combustible material during combustion process. Average concentrations of SO2 and NOx in the flue gas were higher than this received from the combustion of high quality hard coal, 600 ppm and 500 ppm, respectively. Optional reduction of SO2 and NOx emission may require the installation of flue gas desulphurization and de-NOx systems.

The Use of Energy Loss Structures in XPS Characterisation of Surfaces

1985 ◽  
Vol 48 ◽  
Author(s):  
J. E. Castle ◽  
I. Abu-Talib ◽  
S. A. Richardson
Keyword(s):  
Energy Loss ◽  
Aqueous Media ◽  
Mean Free Path ◽  
Organic Films ◽  
Surface Distribution ◽  
Near Surface ◽  
Fitting Procedure ◽  
Peak Fitting ◽  
Distribution Of Elements ◽  
Composite Peak

ABSTRACTThis paper describes advances in the use of the energy loss background associated with individual photoelectron peaks. The subtraction of a Shirley-type background is now normal practice in quantitative XPS analysis. However, in the case of a composite peak containing features from differing depths the subtraction of a common background has a clear disadvantage: i.e. the proportion of background rise associated with each component should be different but is, in fact, fixed. A peak-fitting procedure is described which enables individual backgrounds to be used for each component. The method has been tested using evaporated overlayers and this enables a mean free path for electrons undergoing small energy losses (less than 10 eV) to be determined. The findings are in accord with those of Tougaard and Sigmund and suggest that the use of background intensities in conjunction with the peaks themselves enables the information depth of XPS to be extended by about 10%. A few observations on the behaviour and use in analysis of the large energy loss structure are made.The use of the findings to aid in characterisation of the near surface distribution of elements and ions is described for the following systems: the distribution within oxide films on alloys; the locus of disbondment of organic films on metals; and the surface contamination of surfaces removed from aqueous media.

Design of energy-saving carbon dioxide separation process using fluidized bed

2017 ◽  
Vol 126 ◽  
pp. 134-138 ◽  
Author(s):  
Yasuki Kansha ◽  
Masanori Ishizuka ◽  
Hiroyuki Mizuno ◽  
Atsushi Tsutsumi
Keyword(s):  
Carbon Dioxide ◽  
Energy Saving ◽  
Fluidized Bed ◽  
Separation Process ◽  
Carbon Dioxide Separation
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