Motion in a particle bed agitated by a single blade

AIChE Journal ◽  
2000 ◽  
Vol 46 (9) ◽  
pp. 1723-1734 ◽  
Author(s):  
B. F. C. Laurent ◽  
J. Bridgwater ◽  
D. J. Parker
Keyword(s):  
Particle Bed

scholarly journals Particle Size Effects on Selectivity in Confined Bed Comminution

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 342
Author(s):  
Holger Lieberwirth ◽  
Lisa Kühnel
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Effects ◽  
Experimental Investigations ◽  
Ore Processing ◽  
Tumbling Mills ◽  
Particle Bed ◽  
Vertical Roller

Confined bed comminution in high-pressure grinding rollers (HPGRs) and vertical roller mills (VRMs) was previously used preferably for grinding comparably homogeneous materials such as coal or clinker. Meanwhile, it started to complement or even replace tumbling mills in ore beneficiation with ore and gangue particles of rather different breakage behaviors. The selectivity in the comminution of a mixture of particles with different strengths but similar particle size distribution (PSD) of the constituents in a particle bed was investigated earlier. The strength of a material is, however, also a function of particle size. Finer particles tend to be more competent than coarser ones of the same material. In industrial ore processing using confined bed comminution, this effect cannot be neglected but even be exploited to increase efficiency. This paper presents research results on this topic based on experimental investigations with model materials and with natural particles, which were stressed in a piston–die press. It appeared that the comminution result substantially depends on the material characteristics, the composition of the mixture and the PSD of the constituents. Conclusions will be drawn for the future applications of selective comminution in mineral processing.

scholarly journals Grain-based DEM for Particle Bed Comminution

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 306
Author(s):  
Michael Klichowicz ◽  
Holger Lieberwirth
Keyword(s):  
Grain Size ◽  
Discrete Element Method ◽  
Specific Energy ◽  
Coarse Particles ◽  
Full Understanding ◽  
Real Experiment ◽  
Helpful Tool ◽  
Ore Processing ◽  
Comminution Process ◽  
Particle Bed

The comminution at the grain size level for liberating the valuable minerals usually requires the highest size-specific energy. Therefore, a full understanding of the comminution process at this level is essential. Models based on the Discrete Element Method (DEM) can become a helpful tool for this purpose. One major concern, however, is the missing representativeness of mineral microstructures in the simulations. In this study, a method to overcome this limitation is presented. The authors show how a realistic microstructure can be implemented into a particle bed comminution simulation using grain-based models in DEM (GBM-DEM). The improved algorithm-based modeling approach is exemplarily compared to an equivalent real experiment. The simulated results obtained within the presented study show that it is possible to reproduce the interfacial breakage observed in real experiments at the grain size level. This is of particular interest as the aim of comminution in mineral processing is not only the size reduction of coarse particles, but often an efficient liberation of valuable components. Simulations with automatically generated real mineral microstructures will help to further improve the efficiency of ore processing.

scholarly journals Performance of CVD and CVR Coated Carbon-Carbon in High Temperature Hydrogen

1993 ◽  
Vol 327 ◽  
Author(s):  
J. W. Adams ◽  
R. E. Barlettia ◽  
J. Svandrlik ◽  
P. E. Vanier
Keyword(s):  
Development Process ◽  
Chemical Vapor ◽  
Screening Tests ◽  
Carbon Structure ◽  
Carbon Substrates ◽  
Component Development ◽  
Flowing Hydrogen ◽  
Deposition Processes ◽  
Particle Bed ◽  
Coated Carbon

AbstractAs a part of the component development process for the particle bed reactor (PBR), it is necessary to develop coatings which will be time and temperature stable at extremely high temperatures in flowing hydrogen. These coatings must protect the underlying carbon structure from attack by the hydrogen coolant. Degradation which causes small changes in the reactor component, e.g. hole diameter in the hot frit, can have a profound effect on operation. The ability of a component to withstand repeated temperature cycles is also a coating development issue. Coatings which crack or spall under these conditions would be unacceptable. While refractory carbides appear to be the coating material of choice for carbon substrates being used in PBR components, the method of applying these coatings can have a large effect on their performance. Two deposition processes for these refractory carbides, chemical vapor deposition (CVD) and chemical vapor reaction (CVR) have been evaluated.Screening tests for these coatings consisted of testing of coated 2-D and 3-D weave carbon-carbon in flowing hot hydrogen at one atmosphere. Carbon loss from these samples was measured as a function of time. Exposure temperatures up to 3000 K were used and samples were exposed in a cyclical fashion, cooling to room temperature between exposures. The results of these measurements are presented along with an evaluation of the relative merits of CVR and CVD coatings for this application.

Pressure drop axial distribution uniformity of the particle bed in the radial bed

2021 ◽  
Author(s):  
Tianhang Wu ◽  
Dewu Wang ◽  
Ruojin Wang ◽  
Bin Zhao ◽  
Meng Tang ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Axial Distribution ◽  
Distribution Uniformity ◽  
Particle Bed
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