Synthesis of MnCO3 nanoparticles by microemulsions: statistical evaluation of the effects of operating conditions on particle size distribution

2013 ◽  
Vol 15 (9) ◽  
Author(s):  
Francesca Pagnanelli ◽  
Giuseppe Granata ◽  
Emanuela Moscardini ◽  
Luigi Toro
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Statistical Evaluation ◽  
Operating Conditions

Effect of Particle Size Distribution on the Deep-Bed Capture Efficiency of an Exhaust Particulate Filter

2014 ◽  
Author(s):  
Sandeep Viswanathan ◽  
Stephen S. Sakai ◽  
Mitchell Hageman ◽  
David E. Foster ◽  
Todd Fansler ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Deposition ◽  
Operating Conditions ◽  
Particulate Filter ◽  
Particulate Emissions ◽  
Filter Loading ◽  
Particle Sizer ◽  
The Impact

The exhaust filtration analysis system (EFA) developed at the University of Wisconsin – Madison was used to perform micro-scale filtration experiments on cordierite filter samples using particulate matter (PM) generated by a spark-ignition direct injection (SIDI) engine fueled with gasoline. A scanning mobility particle sizer (SMPS) was used to characterize running conditions with four distinct particle size distributions (PSDs). The distributions selected differed in the relative number of accumulation versus nucleation mode particles. The SMPS and an engine exhaust particle sizer (EEPS) were used to simultaneously measure the PSD downstream of the EFA and the real-time particulate emissions from the SIDI engine to determine the evolution of filtration efficiency during filter loading. Cordierite filter samples with properties representative of diesel particulate filters (DPFs) were loaded with PM from the different engine operating conditions. The results were compared to understand the impact of particle size distribution on filtration performance as well as the role of accumulation mode particles on the diffusion capture of PM. The most penetrating particle size (MPPS) was observed to decrease as a result of particle deposition within the filter substrate. In the absence of a soot cake, the penetration of particles smaller than 70 nm was seen to gradually increase with time, potentially due to increased velocities in the filter as flow area reduces during filter loading, or due to decreasing wall area for capture of particles by diffusion. Particle re-entrainment was not observed for any of the operating conditions.

Hydrodynamics of Multiple Size Particles in a Liquid Fluidized Bed Classifier

2003 ◽  
Author(s):  
Dinesh Gera ◽  
Madhava Syamlal ◽  
Thomas J. O’Brien
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Volume Fraction ◽  
Fluid Model ◽  
Operating Conditions ◽  
Particle Sizes ◽  
Two Fluid Model ◽  
Predicted Values

A two fluid model is extended to an N-phase, multi-fluid model, in which each particulate phase represents a collection of particles with identical diameter and density. The current N-phase model is applied to a fluidized bed classifier with six different particle sizes to investigate the effects of different operating conditions—fluidizing liquid flow rate, feed voidage, and particle size distribution in the feed stream—on the particle size distribution inside the classifier and the discharge streams. The predicted volume fraction of different particle sizes is compared with the experimental data reported by Chen et al. (2002) for two columns, 191 mm and 292 mm in diameter, each having different geometries and containing glass beads of different sizes fluidized with water. A fairly good agreement is observed between the measured and predicted values for mono- and poly-dispersed systems.

Monitoring Fluidization Dynamics for Detection of Changes in Fluidized Bed Composition and Operating Conditions

1999 ◽  
Vol 121 (4) ◽  
pp. 887-894 ◽  
Author(s):  
J. Ruud van Ommen ◽  
Jaap C. Schouten ◽  
Cor M. van den Bleek
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Pressure Fluctuations ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Gradual Change ◽  
Monitoring Method ◽  
Superficial Gas Velocity

In many industrial applications of gas-solids fluidized beds, it is worthwhile to have an on-line monitoring method for detecting changes in the hydrodynamics of the bed (due for example to agglomeration) quickly. In this paper, such a method, based on the short-term predictability of fluidized bed pressure fluctuations, is examined. Its sensitivity is shown by experiments with small step changes in the superficial gas velocity and by experiments with a gradual change in the particle size distribution of the solids in the bed. Furthermore, it is demonstrated that the method is well able to indicate if a stationary hydrodynamic state has been reached after a change in the particle size distribution (a ‘grade change’).

Development of the Bed Particle Size Distribution in a Circulating Fluidized Bed Combustor

2005 ◽  
Author(s):  
Cornelis Klett ◽  
Ernst-Ulrich Hartge ◽  
Joachim Werther
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Calculated Data ◽  
Operating Conditions ◽  
Attrition Rate ◽  
Balance Model ◽  
Fluidized Bed Combustor

In the present work a particle population balance model for a circulating fluidized bed combustor (CFBC) is developed that allows a description of the fate of individual particles in terms of attrition and transport effects. Besides the operating conditions and the particle size distribution the residence time of particles in the system is considered in the modeling of abrasion and shrinking of particles. The model takes account of the fact that fresh particles have a higher attrition rate than particles which have stayed for some time already in the system. The model aims at the description of the dynamic adjustment of the particle size distributions in a given system. The model has been validated with experimental data from a pilot-plant combustor, i.e. a CFBC with an inner diameter of 0.1 m and a height of 15 m. A comparison between experimental and calculated data shows the applicability of the model.

scholarly journals Tailoring hydroxyapatite microspheres by spray-drying for powder bed fusion feedstock

2021 ◽  
Author(s):  
Pedro Navarrete-Segado ◽  
Christine Frances ◽  
David Grossin ◽  
Mallorie Tourbin
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Spray Drying ◽  
Laser Processing ◽  
Operating Conditions ◽  
Air Pressure ◽  
Final Particle ◽  
Powder Bed ◽  
Powder Feedstock

The present work deals with a study on the physical characteristics of hydroxyapatite microspheres produced by spray-drying process through different operating conditions. Obtained hydroxyapatite microspheres will be used as powder feedstock in powder bed selective laser processing additive manufacturing technologies where the flowability and the particle size distribution of the powder feedstock is of special importance. Spray air pressure and solid content of the slurries were the most influent parameters to control the final particle size distribution, while higher air pressure and temperatures gave the higher process recovery rate. The use of polyvinyl alcohol as organic binder increased the granules strength. The produced hydroxyapatite microspheres were found to fulfil the powder bed selective laser processing feedstock requirements, keeping the physico-chemical properties of the material. These promising results confirm the use of a spray dryer as an efficient method for the production of hydroxyapatite microspheres for powder bed selective laser processing.

Particle size distribution to design and operate an APT process for agricultural wastewater reuse

2006 ◽  
Vol 53 (7) ◽  
pp. 43-49 ◽  
Author(s):  
A. Chavez ◽  
C. Maya ◽  
B. Jimenez
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Contact Time ◽  
High Performance ◽  
Wastewater Reuse ◽  
Primary Treatment ◽  
Operating Conditions ◽  
High Rate ◽  
Treatment Objective

Total suspended solids is a parameter commonly used to operate and design coagulation–flocculation processes. Nevertheless, their application for an advanced primary treatment (a high performance but low dose demand coagulation processes coupled with a high rate sedimentator, sometimes called enhanced primary treatment) is not the best option to produce an effluent for agricultural irrigation. This paper compares the best operating conditions obtained using the TSS or the PSD (particle size distribution) as parameters to follow the efficiency. The treatment objective was to remove particles >20 μm, in such conditions that the effluent can contain organic matter and nutrients necessary for crops with a reduced number of helminth ova (with sizes between 20 to 80 μm). Using the TSS as parameter, the best coagulation (460 s−1, 60 s contact time and 300 μmolAl/L) and flocculation (20 s−1 with 15 min) conditions produced an effluent with 1.2 HO/L. To obtain a similar results but using operating conditions determined with the PSD at a three times lower coagulant dose can be employed (diminishing operating costs and reducing the quantity of sludge produced), and a reduction on energy consumption of around eight times can be reached. Best operating conditions defined using the PSD (160 s−1, 60 s contact time and 100 μmolAl/L) produced an effluent with <0.4 HO/L.

scholarly journals The characterisation of diesel exhaust particles – composition, size distribution and partitioning

2016 ◽  
Vol 189 ◽  
pp. 69-84 ◽  
Author(s):  
Mohammed S. Alam ◽  
Soheil Zeraati-Rezaei ◽  
Christopher P. Stark ◽  
Zhirong Liang ◽  
Hongming Xu ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Thermal Desorption ◽  
Volatile Component ◽  
Complex Mixture ◽  
Operating Conditions ◽  
Oxidation Catalyst ◽  
Engine Exhaust

A number of major research questions remain concerning the sources and properties of road traffic generated particulate matter. A full understanding of the composition of primary vehicle exhaust aerosol and its contribution to secondary organic aerosol (SOA) formation still remains elusive, and many uncertainties exist relating to the semi-volatile component of the particles. Semi-Volatile Organic Compounds (SVOCs) are compounds which partition directly between the gas and aerosol phases under ambient conditions. The SVOCs in engine exhaust are typically hydrocarbons in the C15–C35 range, and are largely uncharacterised because they are unresolved by traditional gas chromatography, forming a large hump in the chromatogram referred to as Unresolved Complex Mixture (UCM). In this study, thermal desorption coupled to comprehensive Two Dimensional Gas-Chromatography Time-of-Flight Mass-Spectrometry (TD-GC × GC-ToF-MS) was exploited to characterise and quantify the composition of SVOCs from the exhaust emission. Samples were collected from the exhaust of a diesel engine, sampling before and after a diesel oxidation catalyst (DOC), while testing at steady state conditions. Engine exhaust was diluted with air and collected using both filter and impaction (nano-MOUDI), to resolve total mass and size resolved mass respectively. Adsorption tubes were utilised to collect SVOCs in the gas phase and they were then analysed using thermal desorption, while particle size distribution was evaluated by sampling with a DMS500. The SVOCs were observed to contain predominantly n-alkanes, branched alkanes, alkyl-cycloalkanes, alkyl-benzenes, PAHs and various cyclic aromatics. Particle phase compounds identified were similar to those observed in engine lubricants, while vapour phase constituents were similar to those measured in fuels. Preliminary results are presented illustrating differences in the particle size distribution and SVOCs composition when collecting samples with and without a DOC. The results indicate that the DOC tested is of very limited efficiency, under the studied engine operating conditions, for removal of SVOCs, especially at the upper end of the molecular weight range.

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