scholarly journals Effects of Water Content and Particle Size on Yield and Reactivity of Lignite Chars Derived from Pyrolysis and Gasification

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2717 ◽  
Author(s):  
Yong Huang ◽  
Yonggang Wang ◽  
Hao Zhou ◽  
Yaxuan Gao ◽  
Deliang Xu ◽  
...  
Keyword(s):  
Ex Situ ◽  
Small Particles ◽  
Thermo Gravimetric ◽  
Thermo Gravimetric Analyzer ◽  
Coal Particles ◽  
Large Particles ◽  
Char Structure ◽  
Reaction Atmosphere ◽  
Char Conversion ◽  
Water Contents

Water inside coal particles could potentially enhance the interior char–steam reactions during pyrolysis and gasification. This study aims to examine the effects of water contents on the char conversion during the pyrolysis and gasification of Shengli lignite. The ex-situ reactivities of chars were further analyzed by a thermo gravimetric analyzer (TGA). Under the pyrolysis condition, the increase in water contents has monotonically decreased the char yields only when the coal particles were small (<75 µm). In contrast, the water in only large coal particles (0.9–2.0 mm) has clearly favored the increase in char conversion during the gasification condition where 50% steam in argon was used as external reaction atmosphere. The waved reactivity curves for the subsequent char–air reactions were resulted from the nature of heterogeneity of char structure. Compared to the large particles, the less interior char–steam reactions for the small particles have created more differential char structure which showed two different stages when reacting with air at the low temperature in TGA.

scholarly journals Thermal Analytical Characteristics by TGA-DTA-DSC Analysis of Carica papaya Leaves from Kachchh

2014 ◽  
Vol 26 ◽  
pp. 12-20 ◽  
Author(s):  
Vijay R. Ram ◽  
Pravin N. Ram ◽  
Taslimahemad T. Khatri ◽  
Suhas J. Vyas ◽  
Pragnesh N. Dave
Keyword(s):  
Weight Loss ◽  
Water Loss ◽  
Carica Papaya ◽  
Powder Sample ◽  
Endothermic Peak ◽  
Differential Scanning Calorimetric ◽  
Thermo Gravimetric ◽  
Thermal Analyzer ◽  
Thermo Gravimetric Analyzer ◽  
Reaction Atmosphere

An experimental study on Carica papaya leaves was carried out in Thermo gravimetric analyzer (TGA), Differential Thermal Analyzer (DTA) and Differential Scanning Calorimetric (DSC) analyzer to investigate the effects of reaction atmosphere on thermal chemical characteristics. Experimental results show that In DSC curve, Endothermic peak at 101 °C is attributed to dehydration/Water loss from surface and pores of the powder sample. Step at 215 °C is associated with second order phase transition such as Glass Transition and it should be further confirmed in second heating (During heat- cool- heat cycle). Endothermic peak at 336 °C is associated protease thermal decomposition /Beta Cyclodextrin breakdown. In the TGA Curve, The initial 4 % weight loss is due to water loss from surface/pores of powder sample. Second weight loss between 200-450 °C is associated to degradation of cellulose and hemicellulose.

Structure of Microphase-Separated Silica/Siloxane Molecular Composites

1989 ◽  
Vol 171 ◽  
Author(s):  
Dale W. Schaefer ◽  
James E. Mark ◽  
David Mccarthy ◽  
Li Jian ◽  
C. -C. Sun ◽  
...  
Keyword(s):  
Phase Separation ◽  
Kinetic Studies ◽  
Organic Content ◽  
Small Particles ◽  
X Ray ◽  
Filled Elastomers ◽  
Polymeric Networks ◽  
Large Particles ◽  
Molecular Composites

ABSTRACTThe structure of several classes of silica/siloxane molecular composites is investigated using small-angle x-ray and neutron scattering. These filled elastomers can be prepared through different synthethic protocols leading to a range of fillers including particulates with both rough and smooth surfaces, particulates with dispersed interfaces, and polymeric networks. We also find examples of bicontinuous filler phases that we attribute to phase separation via spinodal decomposition. In-situ kinetic studies of particulate fillers show that the precipitate does not develop by conventional nucleation-and-growth. We see no evidence of growth by ripening whereby large particles grow by consumption of small particles. Rather, there appears to be a limiting size set by the elastomer network itself. Phase separation develops by continuous nucleation of particles and subsequent growth to the limiting size. We also briefly report studies of polymer-toughened glasses. In this case, we find no obvious correlation between organic content and structure.

Adsorption Characteristics of Modified MiL-101(Cr) for Gas (Mainly CH4) Storage Applications

2015 ◽  
Author(s):  
How Wei Benjamin Teo ◽  
Anutosh Chakraborty ◽  
Kim Tiow Ooi
Keyword(s):  
Natural Gas ◽  
X Ray Diffraction ◽  
Uptake Capacity ◽  
N2 Adsorption ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Thermo Gravimetric Analyzer ◽  
Metal Organic ◽  
Ch4 Uptake

As promising material for gas storage applications, MIL-101(Cr) can further be modified by doping with alkali metal (Li+, Na+, K+) ions. However, the doping concentration should be optimized below 10% to improve the methane adsorption. This article presents (i) the synthesis of MIL-101 (Cr) Metal Organic Frameworks, (ii) the characterization of the proposed doped adsorbent materials by X-ray Diffraction, Scanning Electron Microscopy, N2 Adsorption, Thermo-Gravimetric Analyzer, and (iii) the measurements of methane uptakes for the temperatures ranging from 125 K to 303 K and pressures up to 10 bar. It is found that the Na+ doped MIL-101(Cr) exhibits CH4 uptake capacity of (i) 295 cm3/cm3 at 10 bar and 160 K and (ii) 95 cm3/cm3 at 10 bar at 298 K. This information is important to design adsorbed natural gas (ANG) storage tank under ANG-LNG (liquefied natural gas) coupling conditions.

Analysis of the Particles’ Movement Over the Flat and Profiled Rotating Discs surface in the Velocity Layer of the Viscous Gas

2021 ◽  
Vol 6 (2) ◽  
pp. 17-23
Author(s):  
Valeriy I. Pinakov ◽  
Konstantin V. Kulik ◽  
Boris E. Grinberg
Keyword(s):  
Qualitative Difference ◽  
Surface Region ◽  
Vertex Angle ◽  
Oscillation Regime ◽  
Small Particles ◽  
Magnus Force ◽  
Near Surface ◽  
Rotating Discs ◽  
Large Particles ◽  
Velocity Layer

Experiments on the rotating in the air cones with vertex angle β = 120º and flat disc shown that on frequencies Ω ≥ 2.5 hertz exists a qualitative difference in movement for the particles with diameters d ≈ 1 mm and d ≈ 0.1 mm. The particles with d ≈ 0.1 mm move in the near-surface region, the particles with d ≈ 1 mm jump up to 3 cm. Comparison of the spherical and aspheric (ellipsoid with axles d, d and 4 /3 d) particles' kinematics moving shown the inevitability of the large particles jump occurrence. Large particles come to self-oscillation regime by reason of periodically appearance of the Magnus force. Small particles are localized in the velocity layer

Immobilization of K7PW11O39 on ZrO2 Nanofiber: Ultra-deep Desulfurization Based in Extraction Catalytic Oxidation Desulfurization System

2021 ◽  
Vol 72 (3) ◽  
pp. 89-101
Author(s):  
Guowei Zeng ◽  
Guihong Wu ◽  
Zhihui Wang ◽  
Xiaonan Li ◽  
Jie Yang ◽  
...  
Keyword(s):  
Catalytic Oxidation ◽  
Catalytic Mechanism ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
Transmission Electron ◽  
Deep Desulfurization ◽  
Thermo Gravimetric Analyzer ◽  
Ft Ir ◽  
Model Oil

In this work, K7PW11O39 (abbreviated as PW11) was immobilized on ZrO2 nanofibers and used as an efficient recyclable catalyst in extraction catalytic oxidation desulfurization system (ECODS).The 500 ppm DBT model oil(5mL) can desulphurize completely within 20 min with the catalytic conditions of 50��, 0.010 g 50 wt%- CTAB�C PW11�CZrO2 nanofibers and O/S molar ratio H2O2/DBT molar ratio�� was 2:1. The synthesized catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and thermo gravimetric analyzer (TGA). The results indicated the PW11�CZrO2 nanofibers were synthesized successfully and the possible catalytic mechanism is also revealed.

scholarly journals Gravitational differentiation in the regimes from stokes settling to Rayleigh–Raylor flows

2019 ◽  
pp. 15-30
Author(s):  
V. P. Trubitsyn
Keyword(s):  
Viscous Fluid ◽  
Interacting Particles ◽  
Small Particles ◽  
Continuous Transition ◽  
New Approach ◽  
Earth's Core ◽  
The Core ◽  
The Earth ◽  
Large Particles ◽  
Two Component

The Earth’s core was formed under gravitational differentiation in the course of the separation of iron and silicates. Most of the iron has gone into the core as early as when the Earth was growing. However, iron continued to precipitate even during the subsequent partial solidification which developed from the bottom upwards. At the different stages and in the different layers of the mantle, iron was deposited in different regimes. In this paper, the mechanisms of the deposition of a cloud of heavy interacting particles (or drops) in a viscous fluid are considered. A new approach suitable for analytical and numerical tracing the changes in the structure of the flows in a two-component suspension under continuous transition from the Stokessettling (for the case of a cloud of large particles) to the Rayleigh–Taylor flows and heavy diapirs (for the case of a cloud of small particles) is suggested. It is numerically and analytically shown that the both regimes are the different limiting cases of the sedimentation convection in suspensions.

scholarly journals Flow and fouling in a pleated membrane filter

2016 ◽  
Vol 795 ◽  
pp. 36-59 ◽  
Author(s):  
P. Sanaei ◽  
G. W. Richardson ◽  
T. Witelski ◽  
L. J. Cummings
Keyword(s):  
Membrane Fouling ◽  
Membrane Filter ◽  
Small Particles ◽  
Porous Support ◽  
Equal Area ◽  
Membrane Filters ◽  
Membrane Pores ◽  
Dead End ◽  
Large Particles ◽  
Membrane Geometry

Pleated membrane filters are widely used in many applications, and offer significantly better surface area to volume ratios than equal-area unpleated membrane filters. However, their filtration characteristics are markedly inferior to those of equivalent unpleated membrane filters in dead-end filtration. While several hypotheses have been advanced for this, one possibility is that the flow field induced by the pleating leads to spatially non-uniform fouling of the filter, which in turn degrades performance. In this paper we investigate this hypothesis by developing a simplified model for the flow and fouling within a pleated membrane filter. Our model accounts for the pleated membrane geometry (which affects the flow), for porous support layers surrounding the membrane, and for two membrane fouling mechanisms: (i) adsorption of very small particles within membrane pores; and (ii) blocking of entire pores by large particles. We use asymptotic techniques based on the small pleat aspect ratio to solve the model, and we compare solutions to those for the closest-equivalent unpleated filter.

scholarly journals Scattering Properties of Cometary Dust Based on Polarimetric Data

1991 ◽  
Vol 126 ◽  
pp. 249-252
Author(s):  
Sonoyo Mukai ◽  
Tadashi Mukai ◽  
Sen Kikuchi
Keyword(s):  
Linear Polarization ◽  
Phase Function ◽  
Mie Scattering ◽  
Mixing Ratio ◽  
Small Particles ◽  
Cometary Dust ◽  
Maximum Polarization ◽  
Large Particles ◽  
Lower Maximum ◽  
Phase Angles

AbstractReferring to the dust model in Mukai and Mukai(1990), where the scattering by large rough particles and Mie scattering by small particles are taken into account, a phase function of linear polarization of several comets is examined, especially in a region of phase angles α near a maximum polarization. A lower maximum polarization observed in comet Austin(1989c1) than those in comets West(1975n) and P/Halley leads a speculation that a mixing ratio of rough scattering to Mie scattering in comet Austin increases from a sun-comet distance r of 0.6 AU to 1.2 AU. This implies that a shortage of large particles in comet Austin occured in r &lt;1 AU.

scholarly journals Prediction of Horizontal Pneumatic Conveying of Large Coal Particles Using Discrete Phase Model

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Daolong Yang ◽  
Ge Li ◽  
Yanxiang Wang ◽  
Qingkai Wang ◽  
Jianping Li ◽  
...  
Keyword(s):  
Simulation Method ◽  
Phase Model ◽  
Pneumatic Conveying ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Coal Particles ◽  
Large Particles ◽  
Discrete Phase ◽  
Field Velocity ◽  
Conveying System

The pneumatic conveying focusing on gas-solid two-phase flow plays an important role in a conveying system. Previous work has been conducted in the fields of small particles, where the size was less than 5 mm; however, there are few studies regarding large sizes (>5 mm). In order to predict the horizontal pneumatic conveying of large coal particles, the coupling methods based on the Euler–Lagrange approach and discrete phase model (DPM) have been used for the simulated research. Compared with the experimental results under the same working condition, the particle trajectory obtained by simulation is similar to the particle distribution at the same position in the experiment, and it turns out that the simulation method is feasible for the horizontal pneumatic conveying of large particles. Multifactor simulations are also carried out to analyse the effects of particle size, flow field velocity, solid-gas rate, and pipe diameter on the wall abrasion during horizontal pneumatic conveying, which provides simulation reference and design guide for pneumatic conveying of large particles.

Bacillus mycoides phages and their satellites

1984 ◽  
Vol 30 (5) ◽  
pp. 691-698 ◽  
Author(s):  
Anna S. Tikhonenko ◽  
Nina N. Belyaeva ◽  
Anna F. Kretova
Keyword(s):  
Inner Core ◽  
Structural Elements ◽  
Small Particles ◽  
Electron Microscopic ◽  
Bacillus Mycoides ◽  
Specific Antibodies ◽  
Helper Phage ◽  
Electron Microscopic Technique ◽  
Large Particles ◽  
The Relationship

The relationship between large and small particles of phages No. 1M and H17 reproducing simultaneously in one and the same bacterial cell of Bacillus mycoides was studied by the immune electron microscopic technique. The large particles of phages No. 1M and H17 were morphologically identical with phage No. 1 of B. mycoides, whereas only the tails of small particles of phages No. 1M and H17 were morphologically identical with the tail of phage No. 1. Antigens were identified in phages No. 1, No. 1M, and H17 using specific antibodies against phage No. 1, containing only large phage particles, and specific antibodies against phage H17 small heads. It was shown that (i) all structural elements of large particles and tails of small particles of phage No. 1M were antigenically identical with those of phage No. 1; (ii) all structural elements of small and large particles of phage H17, except the inner core of the tail, were antigenically different from phage No. 1; and (iii) the small heads of phages No. 1M and H17 were antigenically identical. Particles of phage No. 1 are morphologically and antigenically identical with the large particles of phage No. 1M and are antigenically different from the large particles of phage H17. Since the tails of small and large particles are antigenically identical in each phage pair (No. 1M and H17), this suggests that in both cases, the genome of a small defective phage codes for the synthesis of head proteins only, whereas its tail is borrowed from the corresponding helper phage. The small phage may therefore be considered as a satellite of the large phage which depends on a helper partner for production of complete particles and whose tail proteins are identical with those of the helper phage.

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