Academic literature on the topic 'Precipitated dust layer'
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Journal articles on the topic "Precipitated dust layer"
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Anđić, Zoran, Marija Korać, and Željko Kamberović. "Treatment of dispersed iron-bearing raw materials and modeling of the protection systems against air-pollution." Metallurgical and Materials Engineering 22, no. 4 (December 31, 2016): 303–12. http://dx.doi.org/10.30544/244.
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Based on the analysis of the non-standard iron-bearing raw materials treatment process and the results of real composition measurements of the flue gas, the study of hazards by identification of harmful substances that occur in the accident, as well as the modeling of the system of protection against air-pollution due to the cancellation of work the bag filter was carried out. Applying the model (Aloha software package) provides an overview of possible developments of events and zones of propagation of the precipitated particulate matter through the share of cadmium (Cd) in them. In the case of malfunction of filter system, emissions of particulate matter enormously exceed the permitted values. In the conditions of the simulated accident, particle velocity of flue gases was amounted E≈738mg/s or 2657g/h of dust. The propagation of the precipitated particulate matter in the lower layer of the atmosphere, downwind, given trough the share of Cd in them, is 100m from the source of pollution for the characteristic density of 5mg/m2×day and 140m for the characteristic density of 2mg/m2×day, in the stable state of the atmosphere, i.e. 870m and 1100m, respectively, in the neutral state of the atmosphere.
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Tugaenko, V. Y., D. S. Ovchinnikov, M. G. Isaenkova, N. I. Kargin, O. A. Krymskaya, A. A. Timofeev, and Y. A. Babich. "The Chemical and Mineral Composition of Particles Precipitated from a Plasma–Dust Layer on the Porthole of the Descend Space Vehicles during The Passage of the Earth’s Atmosphere." Geochemistry International 59, no. 1 (January 2021): 107–12. http://dx.doi.org/10.1134/s0016702921010110.
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Hao, Wen Ge, Xiao Zhen Ren, Meng Cheng Li, and Ru Li. "Study on Non-Static Collection Theory for Dust of Electrostatic Precipitator." Advanced Materials Research 518-523 (May 2012): 2849–53. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.2849.
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In order to further improve the collection efficiency of ESP especially for high-resistivity dust and perfect electrostatic collection theory, how dust layer effects collection efficiency should be revealed more accurately. Taking dust layer as research object, the paper has theoretically analysed the charge distribution of dust layer based on basic principles of electrostatics and Ohm’s Law in order to deduce the formula of the amount of accumulated charge in dust layer. The formula of electric-field strength formed by accumulated charges in collection space was deduced according to the principle of constant voltage and the potential continuity principle of phase boundary. Then the formulas of calculating the effective collecting electric-field and the effective theory migration velocity of charged particles were obtained. The theoretical criterion of occurring back corona was proposed by theoretical analysis of distribution characteristics of electric-field strength in dust layer. Besides that, the elaboration of non-static electrostatic collection theory has enriched and developed the traditional electrostatic collection theory. The paper has player an important role in the design of structure and the selection of operating parameters of ESP, and in the direction to explore the new ways of improving collection efficiency of high-resistivity dust.
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Zhang, Jin Feng, Zai Xing Li, Wei Li, Ying Gao, and Qiang Li. "Numerical Simulation of Air Distribution Plate at the Inlet of Wet Electrostatic Precipitator." Applied Mechanics and Materials 494-495 (February 2014): 756–62. http://dx.doi.org/10.4028/www.scientific.net/amm.494-495.756.
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The air distribution uniformity of electrostatic precipitator is one of the key factors to affect the efficiency of dust collector. A layer of air distribution plate was set in precipitator and its opening rate of distribution plate was adjusted to explore the optimal allocation of air distribution in the precipitator. With the design requirements, we used the Fluent to simulate the airflow distribution in the precipitator. The results show that it can obtain more uniform air distribution to adjust the hole shape and the opening rate of air distribution plate, and the efficiency is ideal when the opening rate is 30%.
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Gao, Wenchao, Yifan Wang, Hao Zhang, Baoyu Guo, Chenghang Zheng, Jun Guo, Xiang Gao, and Aibing Yu. "A Numerical Investigation of the Effect of Dust Layer on Particle Migration in an Electrostatic Precipitator." Aerosol and Air Quality Research 20, no. 1 (2020): 166–79. http://dx.doi.org/10.4209/aaqr.2019.11.0609.
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Jung, Eunsil, Bruce A. Albrecht, Graham Feingold, Haflidi H. Jonsson, Patrick Chuang, and Shaunna L. Donaher. "Aerosols, clouds, and precipitation in the North Atlantic trades observed during the Barbados aerosol cloud experiment – Part 1: Distributions and variability." Atmospheric Chemistry and Physics 16, no. 13 (July 15, 2016): 8643–66. http://dx.doi.org/10.5194/acp-16-8643-2016.
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Abstract. Shallow marine cumulus clouds are by far the most frequently observed cloud type over the Earth's oceans; but they are poorly understood and have not been investigated as extensively as stratocumulus clouds. This study describes and discusses the properties and variations of aerosol, cloud, and precipitation associated with shallow marine cumulus clouds observed in the North Atlantic trades during a field campaign (Barbados Aerosol Cloud Experiment- BACEX, March–April 2010), which took place off Barbados where African dust periodically affects the region. The principal observing platform was the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter (TO) research aircraft, which was equipped with standard meteorological instruments, a zenith pointing cloud radar and probes that measured aerosol, cloud, and precipitation characteristics.The temporal variation and vertical distribution of aerosols observed from the 15 flights, which included the most intense African dust event during all of 2010 in Barbados, showed a wide range of aerosol conditions. During dusty periods, aerosol concentrations increased substantially in the size range between 0.5 and 10 µm (diameter), particles that are large enough to be effective giant cloud condensation nuclei (CCN). The 10-day back trajectories showed three distinct air masses with distinct vertical structures associated with air masses originating in the Atlantic (typical maritime air mass with relatively low aerosol concentrations in the marine boundary layer), Africa (Saharan air layer), and mid-latitudes (continental pollution plumes). Despite the large differences in the total mass loading and the origin of the aerosols, the overall shapes of the aerosol particle size distributions were consistent, with the exception of the transition period.The TO was able to sample many clouds at various phases of growth. Maximum cloud depth observed was less than ∼ 3 km, while most clouds were less than 1 km deep. Clouds tend to precipitate when the cloud is thicker than 500–600 m. Distributions of cloud field characteristics (depth, radar reflectivity, Doppler velocity, precipitation) were well identified in the reflectivity–velocity diagram from the cloud radar observations. Two types of precipitation features were observed for shallow marine cumulus clouds that may impact boundary layer differently: first, a classic cloud-base precipitation where precipitation shafts were observed to emanate from the cloud base; second, cloud-top precipitation where precipitation shafts emanated mainly near the cloud tops, sometimes accompanied by precipitation near the cloud base. The second type of precipitation was more frequently observed during the experiment. Only 42–44 % of the clouds sampled were non-precipitating throughout the entire cloud layer and the rest of the clouds showed precipitation somewhere in the cloud, predominantly closer to the cloud top.
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Pappas, Theodore N. "Heroic Measures for an American Hero: Attempting to save the Life of General Douglas MacArthur." American Surgeon 83, no. 12 (December 2017): 1329–35. http://dx.doi.org/10.1177/000313481708301213.
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General Douglas MacArthur was a towering public figure on an international stage for the first half of the 20th century. He was healthy throughout his life but developed a series of medical problems when he entered his 80s. This article reviews the General's medical care during two separate life-threatening medical crises that required surgical intervention. The first episode occurred in 1960 when MacArthur presented with renal failure due to an obstructed prostate. Four years later after his 84th birthday, MacArthur developed bile duct obstruction from common duct stones. He underwent an uncomplicated cholecystectomy and common duct exploration but developed variceal bleeding requiring an emergent splenorenal shunt. His terminal event was precipitated by strangulated bowel in long-ignored very large inguinal hernias. MacArthur died, despite state-of-the-art surgical intervention, due to renal failure and hepatic coma.
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Oliveira Guimarães, Iliana, Hélio Lucena Lira, Sidinei Kleber da Silva, Suellen Lisboa Dias, and Rosa do Carmo de Oliveira Lima. "Alumina Residue Characterization to Produce Tubular Ceramic Membranes." Materials Science Forum 727-728 (August 2012): 1508–13. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.1508.
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ndustrial wastes recycling become attractive due to raw materials economy (sustainability) and environmental issues. This research objective was to characterize a residue generated during the alumina calcination process (electrostatic precipitator dust), to be applied on the development of tubular ceramic membranes. In this context, two samples were analyzed, a crude residue (sample A) as supplied by the industry and other calcined residue (sample B). As verified by X-ray fluorescence spectroscopy by dispersive energy (XDE), the samples A and B showed a high content of alumina in chemical compositions, both close to 96%. Gibbsite and α-alumina crystalline phases were identified by X-ray diffraction (XRD) in the samples. At scanning electron microscopy (SEM) images, could be observed agglomerates of particles with asymmetric shapes and a wide particle size distribution like was confirmed by laser diffraction, which showed that the particles diameters remained almost unchanged after calcination at 700°C. Results revealed no significant differences between samples characteristics, indicating that the crude and calcined residues could be used to prepare ceramic membranes.
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Bürger, Patrick, and Ulrich Riebel. "Formation of highly resistive SiO2 nanoparticle layers from the aerosol by electrostatic precipitation at 200 °C: observations on back corona and nanoparticle layer structure." Journal of Nanoparticle Research 23, no. 8 (August 2021). http://dx.doi.org/10.1007/s11051-021-05292-4.
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AbstractIn this study, a flame-generated nm-range SiO2 aerosol (approx. 170 nm median aggregate diameter) is fed into an electrostatic precipitator with an operating temperature of 200 °C. While a highly porous layer of SiO2 nanoparticles (NPs) is deposited by electrostatic precipitation, a decrease of current uptake is observed initially, indicating exceptionally high values of the electric field within the layer (> 100 kV/mm) and of the layer resistivity (> 1013 Ω∙cm). Later a strong (13- to 17-fold) increase of current uptake is observed. Aerosol charge measurements show that charges of opposite polarity are emitted from the NP layer. Investigation of the NP layer by SEM shows that charge-emitting structures with a polarity-dependent morphology develop on an originally homogeneous NP layer. Based on the experimental evidence, the mechanisms of charge emission and structure formation are discussed. Charge emission from the precipitated dust layer is known as back corona in the field of electrostatic precipitation. It appears that the mechanisms of back corona observed with SiO2 NP layers are quite distinct from those observed with µm-range particles. While gas discharges inside the NP layer are suppressed due to small pore size, back corona inside the NP layers is apparently initiated by thermionic field emission of free electrons and secondary electron multiplication within the NP layer.
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Romanyuk, Elena, and Andrey Fedorov. "Особенности возникновения и предупреждение взрывоопасных режимов в системах аспирации с фильтрами-пылеуловителями." Pozharnaia bezopasnost`, no. 1(98) (March 31, 2020). http://dx.doi.org/10.37657/vniipo.2020.98.1.010.
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Обоснованы преимущества использования зернистых фильтров в системах аспирации производственных помещений, в которых образуется и обращается горючая пыль. Рассмотрены некоторые известные конструкции, имеющие достаточно узкое применение, однако перспективные для обработки взрывоопасных пылегазовых потоков. Дано описание лабораторного стенда и приведены результаты экспериментальных исследований процесса фильтрования зернистыми фильтрами, подтверждающие необходимость контроля взрывоопасных ситуаций в работе пылеуловителя. Предложен автоматизированный способ контроля аспирации для предупреждения взрывоопасных состояний фильтра.There is a large number of technological operations associated with the treatment of combustible dusts at production facilities. Such industries include food, pharmaceutical, woodworking, metalworking, textile and other industries, the main technological equipment of which is supplemented with aspiration systems. According to the requirements of ecology, labour protection and fire safety, this system must include a dust collector. When choosing a dust collector for such systems granular filters are found particularly effective. They allow to precipitate combustible dust. The article presents the known constructions of granular filters, the narrow application of which is associated with insufficient study of their operation with explosive flows. Therefore, the authors developed an experimental stand and analyzed the operation of different filters: with metal balls, screws, peas and pea mash, grain, which can be used as filter material. During the experiment it was found a state in which the filter operation is explosive. According to the results of the analysis, the criteria for the descriptions of normal and explosive operation are introduced - the criteria of geometric form, characterizes the filter and dust - K, and the rate of filtration - T. Numerical values of criteria are given for automated control of the filter operation. The automated control method of the filter allows to make the operation of the aspiration system more efficient and prevents explosive situations by timely regeneration and replacement of the layer, taking into account the calculated value of criteria K and T. In the scheme there are shown fire extinguishing modules, which are triggered by sensors when the temperature rises above normal.
Dissertations / Theses on the topic "Precipitated dust layer"
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Yuen, Albert Wai Ling Materials Science & Engineering Faculty of Science UNSW. "Collector current density and dust collection in wire-plate electrostatic precipitators." Awarded by:University of New South Wales. Materials Science and Engineering, 2006. http://handle.unsw.edu.au/1959.4/28274.
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Even minimal improvements in particle collection efficiency of electrostatic precipitators significantly reduce dust emission from fossil-fuelled power stations and reduce pollution. Yet current designs rely on the Deutsch collection theory, which was developed for tubular precipitators and has been applied to wire-plate precipitators on the assumption that the inter-electrode electric fields at the same discharge distance in both were similar. Differences in geometry and associated collector electric fields and current density non-uniformity have not been taken into account, although the collector electric field and current density of the wire-plate precipitator are not uniform. And observations show that precipitated dust patterns and the distribution of collector current density are interrelated. Investigations revealed a simple square law relationship between the collector electric field and the collector current density in the space charge dominated coronas. Applying this relationship to the Deutsch collection theory led to a current-density-based collection formula that takes into account the non-uniform collector current density distribution. The current-density-based collection formula is then used to assess the impact of collector current density on collection efficiency, the results closely following published measurements. Applying the current-density-based collection formula to estimate the dust accumulation shows that most of the dust accumulates at collector locations facing the corona wires. The effect of the non-uniform precipitated dust layer on collection performance is assessed using the distributed corona impedance - the ratio of the inter-electrode voltage and the non-uniform collector current. Re-distribution of the collector current profile as dust builds up is also compatible with published measurements. Finally this is applied to optimize the wire-plate precipitator collection performance. This shows that optimal collection performance is obtained with the wire-wire spacing less than the wire-plate distance, once again confirming published experimental results. This is the first analytical approach to show better collection performance can be achieved at the ratio of wire-wire spacing/wire-plate distance not equal to unity, which has been the standard industry practice since 1960.
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Ivanenko, Yevhen. "Modelling and Simulation of Electrostatic Precipitators with a Dust Layer." Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-44773.
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A dust layer, especially based on high-resistivity dust, at the collecting electrodes may cause a back corona discharge in electrostatic precipitators (ESP). It can significantly reduce the ESP efficiency and as a result cause ecological damages. To study the dust layer influence inside ESPs, it is necessary to derive an adequate model of the ESP precipitation process with a dust layer at the collecting electrode. The research of the present thesis is focused on stationary studies of the precipitation process with a dust layer at the collecting electrode in ESPs. Three mathematical models are proposed as a description of the precipitation process with a dust layer at the collecting electrode. The models are based on Maxwell’s equations and the finite element method (FEM). COMSOL Multiphysics software is used for their implementation. In all models the dust layer has constant conductivity and the air region has constant ion mobility. In the first model there are no coupling conditions, which is required in mathematics, are given between the two regions. The solution found by COMSOL Multiphysics does not provide physically acceptable coupling conditions. In the second model, a continuous transition zone is introduced between the two regions so that no coupling conditions are required. With the large derivatives in the transition zone, the nonlinear solver in COMSOL Multiphysics does not converge. Finally, in the third model, the dust layer and the grounded collecting electrode are replaced with a boundary condition for the air region. The properties of the third model are investigated, and these models can be used to study the influence of the dust layer. The results of these investigations are reported and discussed.
Conference papers on the topic "Precipitated dust layer"
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Podliński, Janusz, Anna Niewulis, Jerzy Mizeraczyk, and Pierre Atten. "PIV laser method for investigations of the dust density influence on the dust flow structure in electrostatic precipitator." In SPIE Proceedings, edited by Wieslaw Wolinski, Zdzislaw Jankiewicz, and Ryszard S. Romaniuk. SPIE, 2006. http://dx.doi.org/10.1117/12.726589.
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Rodgers, C., and D. Brown. "Performance Test Diagnosis of a Compact Two Stage High Pressure Ratio Compressor." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22038.
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The intent of this paper was to resolve significant performance shortfalls encountered during the development of a small two stage research 15.0:1 centrifugal compressor designed fabricated and tested in the late 1990’s. The emphasis of the research project was on the aerodynamic flowpath that eliminates use of a large external diameter radial cross-over duct. This was achieved with an innovative small diameter “Sbend” crossover duct, using computational fluid dynamic (CFD) tools of the later 1990’s era to assist in the design process. Test results revealed major performance shortfalls stemming from limited efficient operating ranges of both the 1st stage mixed flow impeller and mixed flow diffuser, which precipitated stage mismatching consequently confining both 1st stage components to operate in semi-stalled modes. The performance of the conventional 2nd stage centrifugal compressor however met design expectations. Eventually program cost limitations curtailed further testing and intended supplementary CFD analyses of the performance deficiencies with more refined computational techniques. During the elapsed decade turbomachinery CFD codes have been extensively refined prompting this renewed diagnosis of the 1st stage mixed flow impeller, mixed flow diffuser and Sbend duct as described within.
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Pilot, Guy, Sylvain Fauvel, Xavier Gosse, and Guillaume de Dinechin. "Dismantling of Evaporators by Laser Cutting: Measurement of Secondary Emissions." In 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/icone14-89709.
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In order to dismantle the evaporators of an obsolete reprocessing plant in Marcoule, studies were carried out by IRSN (Institut de Radioprotection et de Suˆrete´ Nucle´aire)/DSU/SERAC in cooperation with CEA (power laser group) on the laser cutting of steel structures, on the request of COGEMA (now AREVA NC)/Marcoule (UP1 dismantling project manager) and CEA/UMODD (UP1 dismantling owner). The aim of these studies was: • to quantify and to characterize the secondary emissions produced by Nd-YAG laser cutting of Uranus 65 steel pieces representative of UP1 evaporator elements and to examine the influence of different parameters, • to qualify a prefiltration technique and particularly an electrostatic precipitator, • to compare the Nd-YAG used with other cutting tools previously studied. The experiments, which took place in a 35 m3 ventilated cutting cell, allow to underline the following points: • for the Uranus 65 steel, the sedimented dross, the deposits on the walls of the cutting cell and the aerosols drawn in the ventilation exhaust duct (∼ 275 m3/h), represent respectively between 92% and 99%, between 0.01% and 0.25% and between 1% and 8% of the total collected mass, • the attached slag varies much from one configuration to the other and can sometimes amount to a relatively important fraction of the total mass, • the kerves vary from 2 mm up to 7 mm for the Uranus 65 steel plates (thickness: 13.8 mm for the single plate and 12.8 + 3.5 mm for the double plate), • the exhausted aerosol mass per cut length (g/m) decreases with the cutting speed, varies neither with the stand-off nor with the gas pressure, is dependent upon the gas nature (for the double plate), increases with the laser power, is strongly affected by the nature of the steel (stainless steel or mild steel) and is independent upon the plate position, • the size distribution of aerosols is multimodal with a main mode often around 0.45 μm, • the electrostatic precipitator has been a satisfactory prefilter in the experiments with a filtration efficiency greater than 85% and the acoustic declogging system was very useful, • compared to other cutting tools already tested in similar conditions (reciprocating saw, 50 A plasma torch, 200 A plasma torch, grinder, 1 kW laser without assistant gas, arc-air and arc saw), the 4 kW laser produced less secondary emissions than all other tools and less aerosols than the other thermal tools.