scholarly journals Investigation of the movement of charge materials in the tray-distributor of the cone-free loading device of the blast furnace

2020 ◽  
Vol 2,2020 (2,2020 (125)) ◽  
pp. 44-53
Author(s):  
Selegej A ◽  
Selegej S
Keyword(s):  
Blast Furnace ◽  
Flow Rate ◽  
Analytical Calculation ◽  
Particle Diameter ◽  
Practical Significance ◽  
Average Particle ◽  
Charge Movement ◽  
Charge Materials ◽  
Loading Device ◽  
A Charge

Objective.Determine the analytical dependence of the profile of granular materials moving on the tray-distributor of the cone-free loading device on the length coordinate. Method. Kinematic and geometrical regularities of movement of charge materials on the distributive body of the cone - free loading device of tray type are considered. It is shown that the dynamics of the flow of charge materials is significantly influenced by such factors as the value of the average particle diameter of the loaded material, physical and mechanical characteristics of the charge, its flow rate, angular velocity of the distributor tray and its angle. Results. The analysis of the obtained results makes it possible to calculate with sufficient accuracy the rate of charge rise from the tray-distributor in the furnace space of the blast furnace. This makes it possible to calculate the trajectory of the charge flow in the furnace space and to obtain the coordinate of the intersection of the trajectory with the surface of the charge backfill on the blast furnace grate. The obtained equation of the profile of the movement of charge materials on the tray-distributor makes it possible to recommend the position of the tray when loading the blast furnace, which prevents the transfer of the charge through the edge of the tray. Scientific novelty. A new method for solving the Cauchy problem for a differential equation describing the flow of a charge through a distributor tray is proposed. It is established that the change in the flow rate of charge materials passing through the tray-distributor significantly affects the configuration of the surface of the charge on the tray, and this, in turn, causes a change in the rate of flow into the furnace space. Studies have shown that the motion parameters are significantly affected by the initial height of the charge materials on the tray. Practical significance. The obtained results allow analytical calculation of the change in the dynamics of the charge movement under the condition of a constant angle of inclination of the tray of the loading device of the blast furnace. This makes it possible to expand the possibilities of automatic correction of the gas dynamics of the blast furnace zone in specific charge conditions.

Adsorption of safranine T from aqueous medium by nano mesoporous MCM-41: adsorption equilibrium, kinetics, and thermodynamics

2020 ◽  
Vol 10 ◽  
Author(s):  
Xiao-Dong Li ◽  
Qing-Zhou Zhai
Keyword(s):  
Electron Microscopy ◽  
Ph Value ◽  
Particle Diameter ◽  
Spherical Particles ◽  
Practical Significance ◽  
Average Particle ◽  
Average Pore ◽  
Kinetics And Thermodynamics ◽  
Safranine T ◽  
Mcm 41

Introduction: In industrial production, a small amount of saffron T emissions will cause increase of water color and increase of chemical oxygen consumption, so study of the decolorization of saffron T wastewater has an important practical significance. Methods: MCM (Mobil Composition of Matter)-41 molecular sieve was synthesized by hydrothermal method. Power Xray diffraction and scanning electron microscopy were used to characterize the sample. Safranine T dye was adsorbed from water by the MCM-41 prepared. Kinetics and thermodynamics of the adsorption were studied. Results: The MCM-41 sample presented spherical particles and regular. The BET (Brunner-Emmett-Teller) specific surface area of the sample determined by 77 K low temperature nitrogen adsorption-desorption isotherm was 932 m2 /g. Its average particle diameter was 110 nm. TEM (transmission electron microscopy) results showed that the sample structure presented a honeycomb pore structure and the average pore diameter was 3.0 nm. The results showed that when room temperature was 20 ± 1 ℃, adsorbate safranine T: adsorbent MCM-41 = 20 : 1，the optimum pH value of adsorption was 4.0 and contact time was 20 min, the adsorption rate reached 98.29% and the adsorption capacity was 19.66 mg/g. The entropy change and enthalpy change of the adsorption system are respectively ΔS0 = 157.5 J/(mol·K); ΔH0 = 21.544 kJ/mol. When temperature was 277.15, 293.15, 303.15 K，the free energy change was respectively △G1 0 = -22.107 kJ/mol, △G2 0 = -24.627 kJ/mol, △G3 0 = -26.202 kJ/mol. Conclusion: The adsorption of safranine T by MCM-41 belongs to a pseudo-second-order adsorption. This adsorption accords with the Freundlich equation and belongs to a heterogeneous adsorption. The adsorption is an endothermic reaction of entropy increase, being spontaneous.

scholarly journals A Comparative Evaluation of Nanohydroxyapatite-Enriched Hydrogen Peroxide Home Bleaching System on Color, Hardness and Microstructure of Dental Enamel

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3072
Author(s):  
Riccardo Monterubbianesi ◽  
Vincenzo Tosco ◽  
Tiziano Bellezze ◽  
Giampaolo Giuliani ◽  
Mutlu Özcan ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Particle Diameter ◽  
Dental Enamel ◽  
Sem Analysis ◽  
Control Group ◽  
Average Particle ◽  
Color Analysis ◽  
Enamel Microstructure ◽  
Prismatic Structure ◽  
20 Nm

This study aimed to evaluate two hydrogen peroxide (HP)-based at-home bleaching systems in order to analyze whether nano-hydroxyapatite (nHA) addition may represent a reliable and safe solution for tooth whitening without altering dental microstructure and hardness. Human third molars (N = 15) were treated with two bleaching agents, one containing 6%HP (6HP) and the other 6% HP nHA-enriched (6HP-nHA) with average particle diameter ranging from 5–20 nm. Their effects on enamel were assessed using a spectrophotometer, Vickers microhardness (VMH) test and Scanning Electron Microscopy (SEM), comparing the treated groups with the non-treated control group (CTR). Color analysis revealed improvement in whiteness in both groups compared to CTR. VMH test results showed no differences among the groups. SEM analysis highlighted no evident changes in the enamel microstructure of tested groups compared to CTR. At high magnification, in 6HP group, a slight increase in irregularities of enamel surface morphology was observed, while 6HP-nHA group displayed removal of the aprismatic layer but preservation of the intact prismatic structure. These results suggest that the 6HP-nHA agent may be recommended to provide reliable whitening treatment, without damaging the enamel micromorphology and hardness.

The Investigation of Back-Mixing Particles near Dust Outlet in Cyclone Separator with Tangential Inlet

2011 ◽  
Vol 239-242 ◽  
pp. 2142-2148
Author(s):  
Hui Min Tan ◽  
Jian Jun Wang ◽  
You Hai Jin
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Particle Diameter ◽  
Particle Mass ◽  
Cyclone Separator ◽  
Axial Distribution ◽  
Computational Fluid Dynamics Analysis ◽  
Back Mixing ◽  
Tangential Inlet

Based on experimental and computational fluid dynamics analysis, the phenomenon of particle back-mixing near the dust outlet in cyclone separator with tangential inlet was studied. The results show that particle back-mixing appears near the dust outlet geometry. Particle back-mixing can be divided into dust hopper back-mixing and discharge cone back-mixing for different generation mechanism. The upward flow coming from dust hopper, which occupies 17.7% of the inlet gas, can induce dust hopper back-mixing. The particle mass flow rate that caused by dust hopper back-mixing occupies 46.6% of total inlet particle mass flow rate. Precessing vortex core, bias flow and high turbulent intensity near the dust outlet can induce discharge cone back-mixing. For both dust hopper back-mixing and discharge cone back-mixing, particle back-mixing is serious near the dust outlet geometry, which occupies 56.8% of total inlet particle mass flow rate. Particle which is smaller than 18μm can mix backward. The axial distribution of particle concentration decreases sharply in a range of 1.5 D (cyclone diameter) height above the dust discharge port. At last, only 2.6% of back-mixing particles with diameter no bigger than 13μm escape from vortex finder. This effect on separator efficiency increases with the particle diameter decreases.

An Efficient Immersed Boundary Method Based on Penalized Direct Forcing for Simulating Flows Through Real Porous Media

2012 ◽  
Author(s):  
Wim-Paul Breugem ◽  
Vincent van Dijk ◽  
René Delfos
Keyword(s):  
Porous Medium ◽  
Ct Scan ◽  
Immersed Boundary Method ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Particle Diameter ◽  
Immersed Boundary ◽  
Average Particle ◽  
Boundary Method ◽  
Direct Forcing

A computationally efficient Immersed Boundary Method (IBM) based on penalized direct forcing was employed to determine the permeability of a real porous medium. The porous medium was composed of about 9000 glass beads with an average particle diameter of 1.93 mm and a porosity of 0.367. The forcing of the IBM depends on the local solid volume fraction within a computational grid cell. The latter could be obtained from a high-resolution X-ray Computed Tomography (CT) scan of the packing. An experimental facility was built to determine the permeability of the packing experimentally. Numerical simulations were performed for the same packing based on the data from the CT scan. For a scan resolution of 0.1 mm the numerical value for the permeability was nearly 70% larger than the experimental value. An error analysis indicated that the scan resolution of 0.1 mm was too coarse for this packing.

scholarly journals Novel Robust Design Method of Multilayer Optical Coatings

ISRN Optics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Suyong Wu ◽  
Xingwu Long ◽  
Kaiyong Yang
Keyword(s):  
Robust Design ◽  
Optimization Design ◽  
Design Method ◽  
Analytical Calculation ◽  
Design Procedure ◽  
Deposition Process ◽  
Practical Significance ◽  
Optical Coatings ◽  
Optical Films ◽  
Robust Design Method

We present a novel fast robust design method of multilayer optical coatings. The sensitivity of optical films to production errors is controlled in the whole optimization design procedure. We derive an analytical calculation model for fast robust design of multilayer optical coatings. We demonstrate its effectiveness by successful application of the robust design method to a neutral beam splitter. It is showed that the novel robust design method owns an inherent fast computation characteristic and the designed film is insensitive to the monitoring thickness errors in deposition process. This method is especially of practical significance to improve the mass production yields and repetitive production of high-quality optical coatings.

scholarly journals Preparation of Polyetherimide Nanoparticles by a Droplet Evaporation-Assisted Thermally Induced Phase-Separation Method

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1548
Author(s):  
Peng Zhu ◽  
Huapeng Zhang ◽  
Hongwei Lu
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Phase Separation ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Droplet Evaporation ◽  
Average Particle ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Pei Nanoparticles

The droplet evaporation effect on the preparation of polyetherimide (PEI) nanoparticles by thermally induced phase separation (TIPS) was studied. PEI nanoparticles were prepared in two routes. In route I, the droplet evaporation process was carried out after TIPS. In route II, the droplet evaporation and TIPS processes were carried out simultaneously. The surface tension and shape parameters of samples were measured via a drop shape analyzer. The Z-average particle diameter of PEI nanoparticles in the PEI/dimethyl sulfoxide solution (DMSO) suspension at different time points was tested by dynamic light scattering, the data from which was used to determine the TIPS time of the PEI/DMSO solution. The natural properties of the products from both routes were studied by optical microscope, scanning electron microscope and transmission electron microscope. The results show that PEI nanoparticles prepared from route II are much smaller and more uniform than that prepared from route I. Circulation flows in the droplet evaporation were indirectly proved to suppress the growth of particles. At 30 °C, PEI solid nanoparticles with 193 nm average particle size, good uniformity, good separation and good roundness were obtained. Route I is less sensitive to temperature than route II. Samples in route I were still the accumulations of micro and nanoparticles until 40 °C instead of 30 °C in route II, although the particle size distribution was not uniform. In addition, a film structure would appear instead of particles when the evaporation temperature exceeds a certain value in both routes. This work will contribute to the preparation of polymer nanoparticles with small and uniform particle size by TIPS process from preformed polymers.

Preparation and pharmacokinetics of cefquinome sulfate liposomes in goats

2018 ◽  
Author(s):  
Haigang Wu ◽  
Jinni Liu ◽  
Gugangke Xu ◽  
Zhaowei Ye ◽  
Jicheng Liu and Benchi Yi
Keyword(s):  
Plasma Concentration ◽  
Particle Diameter ◽  
Entrapment Efficiency ◽  
Maximum Plasma Concentration ◽  
Maximum Plasma ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Ethanol Injection ◽  
Elimination Half ◽  
Time Point

We evaluated the pharmacokinetics of cefquinome sulfate (CEF) liposomes in eight healthy goats following intramuscular administration at 4 mg/kg. The average particle diameter of CEF liposomes prepared by the ethanol injection method was 335nm with a CEF entrapment efficiency of 69.56%. The elimination half-life (t1/2b) of CEF liposomes was 33.04h compared with 16.21 h for CEF injected without carrier (p less than 0.05). The area under the concentration curve (AUC) for CEF liposomes was approximately three-times greater than for CEF alone (P less than 0.05). The time-point of maximum plasma concentration of the drug (Tp) and the maximum plasma concentration (Cmax) were 4.38 h and 1.99 ìg/mL for CEF liposomes, compared with 1.86 h and 3.55 ìg/mL for CEF without carrier, respectively. 

JUSTIFICATION OF THE USE OF METALLURGICAL SLAGS AS A BACKFILL MATERIAL FOR QUARRY CAVITIES

2021 ◽  
pp. 15-25
Author(s):  
Volodymyr Bondarenko ◽  
◽  
Oleksandr Filonenko ◽  
Mykhailo Petlovanyi ◽  
Vladyslav Ruskykh ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Large Scale ◽  
Experimental Studies ◽  
Metallurgical Slag ◽  
Open Pit ◽  
Practical Significance ◽  
Steel Smelting ◽  
Backfill Material ◽  
Steel Making ◽  
Metallurgical Slags

Purpose. Experimental studies of the interaction of blast-furnace and steel-making slags with open pit waters during their direct contact and assessment of the volume of filling of the formed man-made cavities during mining of mineral deposits. Methods. Based on the analysis, the current low level of metallurgical slag and the lack of real and effective directions of their large-scale utilization were determined. The laboratory studies of the interaction of metallurgical slags with open pit water at a certain time of interaction, generally accepted methods for studying the chemical composition and concentration of substances in water, computer-aided design software packages and drawings to determine the volumes of the open pit mined-out area were used. Results. The dynamics of changes in the products of interactions of steel-smelting slags with open-pit waters at a certain ratio and period of interaction was investigated. It was found that the concentration of pollutants upon contact of water with steel-making slag changes according to polynomial dependences on the time of their interaction, decreasing by the 30th day, which eliminates the danger for the aquifer. The safest type of metallurgical slag was recommended for the formation of the bottom layer of the backfill massif. The volumes of the mined-out area of the open pit were determined in detail to assess the volumes of placement of the backfill material based on metallurgical slags. Scientific novelty. The safety of the contact of backfill materials based on steelmaking slags with open pit water was scientifically proven, which is confirmed by the established polynomial patterns of changes in concentrations and pollutants from the ratio and time of interaction. Practical significance. The formation of the backfill massif on the basis of blast-furnace dump and steel-smelting slags will allow achieving an environmental effect, such as their safe disposal as a reclamation of technologically disturbed lands by mining and restoration of the economic value of the land plot, as well as preventing the formation of new dumps.

Adjustment of a technology of cast iron smelting in the blast furnace of jsc "ural steel" w ith a volume of 1232 см3 with charge h a v in g 95% share of Mikhailovskii GOK pellets

2021 ◽  
Vol 77 (7) ◽  
pp. 768-775
Author(s):  
I. F. Iskakov ◽  
G. A. Kunitsyn ◽  
D. V. Lazarev ◽  
А. А. Red`kin ◽  
S. A. Trubitsyn ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Iron Ore ◽  
Raw Materials ◽  
Raw Material ◽  
Material Base ◽  
Hot Metal ◽  
Charging System ◽  
Iron Smelting ◽  
Gas Consumption ◽  
A Charge

To use effectively internal raw material base, JSC “Ural Steel” accomplished I category major overhaul of the blast furnace No. 2. The main purpose of the overhaul was to design a rational profile which could ensure an ability to operate with a charge containing 95 % of Mikhailovskii GOK (mining and concentrating plant) pellets having basicity of 0.5 by CaO/SiO2. The blast furnace No. 2 having useful volume of 1232 m3, was constructed by design of Danieli Corus, the Netherlands, and was blown in on December 30, 2020. In the process of guarantee tests, step-by-step increase of Mikhailovskii GOK pellets (Fetotal = 60.5 %, CaO/SiO2 = 0.5) content in the charge iron ore part was being accomplished from 55 to 95.1%. Charging of the blend containing pellets in the amount of 55% of iron ore part, was done by charging system 4OOCC + 1COOCC (Ore - Coke) with filling level 1.5 m. Under conditions of pellets part increase in the blend, the charging system was changed to decrease their content at the periphery, to increase it in the ore ridge zone and make it intermediate between periphery and the ore ridge. At the pellets share in the iron ore raw materials 0.75 the charging system was used as the following: 3OOCC + 1COOC + 1COOCC, while at the content 95.1% the following charging system was used: 2COOC + 2COOC + 1COOCC. It was noted that in the period of guarantee tests the furnace running was smooth. The average silicon content in the hot metal was 0.70% at the standard deviation 0.666. Sulfur content in the hot metal did not exceed 0.024%, the blowing and natural gas consumption figures were 2100 m3/min and 11000 m3/min correspondently, oxygen content in the blowing 26.5%, hot blowing and top smoke pressure figures were 226.5 and 109.8 KPa correspondently. The productivity of the furnace was reached as high as 2358 t/day at the specific coke rate 433 kg/t of hot metal. After guarantee tests completion, the pellets content in the iron ore part was decreased gradually from 95 down to 50%. The decreasing was made by 5% in every 6 hours of operation. Application of the mastered technology of the blast furnace No. 2 with the increased share of pellets will enable to stably supply the blast furnaces No. 1, 3 and 4 by iron ore raw materials in the proportion of 30-35% of pellets and 65-70% of sinter.

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