scholarly journals The Influences of Stirring on the Recrystallization of Ammonium Perrhenate

2020 ◽  
Vol 10 (2) ◽  
pp. 656 ◽  
Author(s):  
Junjie Tang ◽  
Li Feng ◽  
Chunwei Zhang ◽  
Yuan Sun ◽  
Long Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Liquid Flow ◽  
Physical Simulation ◽  
Powder Processing ◽  
Crystal Plane ◽  
Recrystallization Process ◽  
Low Velocity ◽  
Flow Area ◽  
Ammonium Perrhenate ◽  
Turbine Impeller

Ammonium perrhenate is widely used in alloy manufacturing, powder processing, the catalytic industry, and other fields. Recrystallization can improve the specific surface area of ammonium perrhenate, reduce its particle size, and improve its particle size distribution uniformity. Therefore, recrystallized ammonium perrhenate can obtain better application benefits in the above fields. Stirring is an important factor that affects the recrystallization of ammonium perrhenate, and this paper systematically analyzes the influence of the stirring paddle types and stirring intensities on ammonium perrhenate during the homogeneous recrystallization process, ultimately revealing the relationship between the growth rate of ammonium perrhenate and the stirring process. Particle image velocimetry physical simulation results showed that the flow field in the reactor was more evenly distributed when using the disc turbine impeller, and a relatively uniform velocity liquid flow area was formed in the whole reactor, while the low-velocity liquid flow area was smaller. Therefore, this information, combined with SEM test results, suggests that under the same recrystallization time and stirring intensity, the stirring effect of a disc turbine impeller is more suitable than a propelling propeller and an Intermig impeller for the recrystallization process of ammonium perrhenate. Moreover, the XRD patterns and SEM analysis showed that if the agglomeration in the systems was too strong or too weak, the growths of the (101) crystal plane and (112) crystal plane were restrained, which caused an attenuation in the growth rates along the crystallographic directions that were orthogonal to the crystal faces. Finally, the reduction experiments show that the recrystallization of ammonium perrhenate could improve the phase parameters of rhenium powders.

scholarly journals A broadband E-shaped piezoelectric energy harvester based on vortex-shedding induced vibration from low velocity liquid flow

AIP Advances ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 125214 ◽  
Author(s):  
Yili Hu ◽  
Fangxiao Mou ◽  
Bin Yang ◽  
Xiang Chen ◽  
Xiaolin Wang ◽  
...  
Keyword(s):  
Liquid Flow ◽  
Vortex Shedding ◽  
Energy Harvester ◽  
Low Velocity ◽  
Piezoelectric Energy

Formation Pressure Analysis of Water-Bearing Tight Gas Reservoirs with Unsteady Low-Velocity Non-Darcy Flow

2011 ◽  
Vol 201-203 ◽  
pp. 399-403 ◽  
Author(s):  
Hong Qing Song ◽  
Ming Yue ◽  
Wei Yao Zhu ◽  
Dong Bo He ◽  
Huai Jian Yi
Keyword(s):  
Liquid Flow ◽  
Gas Flow ◽  
Darcy Flow ◽  
Tight Gas ◽  
Formation Pressure ◽  
Low Velocity ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs ◽  
Calculation Results ◽  
Pressure Analysis

Porous media containing water is the prerequisite of existence of threshold pressure gradient (TPG) for gas flow. Based on theory of fluid mechanics in porous medium considering TPG, the non-Darcy flow mathematical model is established for formation pressure analysis of water-bearing tight gas reservoirs. It could provide semi-analytic solution of unsteady radial non-Darcy flow. According to the solution of unsteady radial non-Darcy flow, an easy and accurate calculation method for formation pressure analysis is presented. It can provide theoretical foundation for development design of water-bearing tight gas reservoirs. The analysis of calculation results demonstrates that the higher TPG is, the smaller formation pressure of water-bearing tight gas reservoirs spreads. In the same output, the reservoir sweep of non-Darcy gas flow is larger than that of non-Darcy liquid flow. And the pressure drop near wellbore is smaller than that of non-Darcy liquid flow, which is different from Darcy flow.

scholarly journals Reaction Mechanism and Process Control of Hydrogen Reduction of Ammonium Perrhenate

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 640
Author(s):  
Junjie Tang ◽  
Yuan Sun ◽  
Chunwei Zhang ◽  
Long Wang ◽  
Yizhou Zhou ◽  
...  
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Hydrogen Reduction ◽  
Reduction Rate ◽  
Reduction Reaction ◽  
High Density ◽  
Reduction Temperature ◽  
Ammonium Perrhenate

The preparation of rhenium powder by a hydrogen reduction of ammonium perrhenate is the only industrial production method. However, due to the uneven particle size distribution and large particle size of rhenium powder, it is difficult to prepare high-density rhenium ingot. Moreover, the existing process requires a secondary high-temperature reduction and the deoxidization process is complex and requires a high-temperature resistance of the equipment. Attempting to tackle the difficulties, this paper described a novel process to improve the particle size distribution uniformity and reduce the particle size of rhenium powder, aiming to produce a high-density rhenium ingot, and ammonium perrhenate is completely reduced by hydrogen at a low temperature. When the particle size of the rhenium powder was 19.74 µm, the density of the pressed rhenium ingot was 20.106 g/cm3, which was close to the theoretical density of rhenium. In addition, the hydrogen reduction mechanism of ammonium perrhenate was investigated in this paper. The results showed that the disproportionation of ReO3 decreased the rate of the reduction reaction, and the XRD and XPS patterns showed that the increase in the reduction temperature was conducive to increasing the reduction reaction rate and reducing the influence of disproportionation on the reduction process. At the same reduction temperature, reducing the particle sizes of ammonium perrhenate was conducive to increasing the hydrogen reduction rate and reducing the influence of the disproportionation.

ChemInform Abstract: THE DISCHARGE LIQUID FLOW FROM THE TURBINE IMPELLER

1975 ◽  
Vol 6 (6) ◽  
Author(s):  
J. KRATKY ◽  
I. FORT ◽  
J. DRBOHLAV
Keyword(s):  
Liquid Flow ◽  
Turbine Impeller

The discharge liquid flow from the turbine impeller

1974 ◽  
Vol 39 (11) ◽  
pp. 3238-3245 ◽  
Author(s):  
J. Krátký ◽  
I. Fořt ◽  
J. Drbohlav
Keyword(s):  
Liquid Flow ◽  
Turbine Impeller

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

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Sandeep Viswanathan ◽  
David Rothamer ◽  
Stephen Sakai ◽  
Mitchell Hageman ◽  
David Foster ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Deposition ◽  
Operating Conditions ◽  
Particulate Filter ◽  
Particulate Emissions ◽  
Flow Area ◽  
Wall Area ◽  
Filter Loading ◽  
Particle Sizer ◽  
The Impact

The exhaust filtration analysis system (EFA) developed at the University of Wisconsin–Madison was used to perform microscale 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 (FE) 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 PSD 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.

scholarly journals A Hot Spots Ignition Probability Model for Low-Velocity Impacted Explosive Particles Based on the Particle Size and Distribution

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Hong-fu Guo ◽  
Yan-qing Wu ◽  
Feng-lei Huang
Keyword(s):  
Particle Size ◽  
Probability Model ◽  
Quadratic Function ◽  
Drop Height ◽  
Low Velocity ◽  
Contact Zones ◽  
Ignition Probability ◽  
Drop Weight ◽  
Mean Size ◽  
Size Of Particles

Particle size and distribution play an important role in ignition. The size and distribution of the cyclotetramethylene tetranitramine (HMX) particles were investigated by Laser Particle Size Analyzer Malvern MS2000 before experiment and calculation. The mean size of particles is 161 μm. Minimum and maximum sizes are 80 μm and 263 μm, respectively. The distribution function is like a quadratic function. Based on the distribution of micron scale explosive particles, a microscopic model is established to describe the process of ignition of HMX particles under drop weight. Both temperature of contact zones and ignition probability of powder explosive can be predicted. The calculated results show that the temperature of the contact zones between the particles and the drop weight surface increases faster and higher than that of the contact zones between two neighboring particles. For HMX particles, with all other conditions being kept constant, if the drop height is less than 0.1 m, ignition probability will be close to 0. When the drop heights are 0.2 m and 0.3 m, the ignition probability is 0.27 and 0.64, respectively, whereas when the drop height is more than 0.4 m, ignition probability will be close to 0.82. In comparison with experimental results, the two curves are reasonably close to each other, which indicates our model has a certain degree of rationality.

scholarly journals The study of the process of physic-chemical destruction of coal by the method of physical modeling

2019 ◽  
Vol 109 ◽  
pp. 00054
Author(s):  
Serhii Makeiev ◽  
Serhii Andreiev ◽  
Hennadii Ryzhov
Keyword(s):  
Particle Size ◽  
Hydrochloric Acid ◽  
Surface Energy ◽  
Physical Modeling ◽  
Laboratory Experiments ◽  
Physical Simulation ◽  
Treated Area ◽  
Chemical Destruction ◽  
Clay Rocks ◽  
Physical And Chemical

One of the possible ways of physic-chemical destruction (PCD) of coal was considered. It is established that condition of the realization of a principle possibility of spontaneous dispersion of coal is to reduce its surface energy by 40-60 J/m2. Laboratory experiments to study the PCD of coal in different liquids were conducted. According to the results, kinetic curves of swelling coal in them transition D-G stamps is presents. It was established that the most intensive physical and chemical destruction of the coal to a particle size from tenths to tens of millimeters occurs in solutions of methylamine and hydrochloric acid. The most severe swelling of the coal was noted in those environment as well. The intensity of swelling is not significantly associated with the characteristics of wetting. The influence of various effects on the PCD parameters of coal was studied by physical simulation. The total time the chemical destruction of coal on the treated area was calculated. It was proposed method PCD for coals occurring in the clay rocks of various stages of catagenesis.

Performance promotion of Ag2O photocatalyst by particle size and crystal surface regulation

2020 ◽  
Vol 44 (25) ◽  
pp. 10719-10728
Author(s):  
Jian He ◽  
Hongyan Fu ◽  
Pan Wu ◽  
Zehao Lin ◽  
Ya Zeng ◽  
...  
Keyword(s):  
Particle Size ◽  
Wastewater Treatment ◽  
Photocatalytic Performance ◽  
Crystal Surface ◽  
Crystal Plane ◽  
Dyeing Wastewater ◽  
Printing And Dyeing Wastewater ◽  
Wastewater Treatment Systems

Photocatalytic performance of Ag2O was greatly improved by adjusting the crystal plane structure and size with pyridine, which promoted the application of Ag2O to actual industrial printing and dyeing wastewater treatment systems.

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