Review of coal-water fuel pulverization technology and atomization quality registration methods

Possibilities of coal-water fuel application in industrial power engineering are considered and described. Two main problems and disadvantages of this fuel type are suggested. The paper presents information about liquid fuel atomization technologies and provides data on nozzle type for coal-water fuel pulverization. This article also mentions some of the existing technologies for coal-water slurry spraying quality determination

Study of Electrophysical Intrastratal Gasification at Different Coal Heating Rate

Experimental instrumental multi-method research, electrophysical ihtrastratal gasification of antracite with further definition of quantitative syngas composition and its combustion heat design at different heating rates. It was stated that concentration of carbon dioxide CO[2], hydrogen H[2] decreases with heating rate increase in received syngas, and there is rise of carbon monoxide CO concentration. The results of the research showed that heating rate increase leads to a small rise of combustion heat as decrease of H[2] and CH[4] concentration is compensated with increase of CO

Research of Mechanical Treatment Influence on Rheological Properties of Coal-Water Fuel Based on Low-Grade 3B Coal

Experimental study of mechanical treatment effect of rotary flow modulation device on coal-water fuel rheological properties were conducted. The slurry was prepared on the basis of low-grade 3B coal from Balakhtinskoe deposit

Characteristics of alcohol-coal-water slurries spraying

The aim of this work is to substantiate the efficiency of ethyl or isoamyl alcohol application as the third component of coal-water fuels based on the results of experimental study of coaxial spraying. Studies of alcohols influence on spraying characteristics of coal-water fuels can rarely be found in the literature. Instantaneous fields of fuel droplets velocities in several cross-sections of the jet were determined using Particle Image Velocimetry method. Interferometric Particle Imaging method was used to determine droplets distribution by size in the jet of sprayed coal-water fuel. It was experimentally established that substitution of water (no more than 3 % by weight) in the composition of coal-water slurry by fairly typical alcohols leads to decrease in droplet velocities of alcohol-coal-water slurries in comparison with conventional coal-water fuel by 15-18 %. Concentration of sufficiently small fuel droplets (up to 200 microns) increases by 13.4±0.2 % and by 6.6±0.2 % during atomization of alcohol-coal-water slurries with addition of ethyl and isoamyl alcohol, respectively. Introduction of no more than 5 % by weight of the studied alcohols into the coal-water slurry will reduce the cost of fuel by 15-73 % in comparison with fuel oil. Influence of small additives of ethyl and isoamyl alcohol in the composition of coal-water fuel on spraying characteristics proves the possibility of efficient application of such three-component slurries in thermal power engineering. The results obtained are of practical significance, since they illustrate the possibility of reducing the ignition delay time for droplets of alcohol-coal-water slurries after they are sprayed in the furnaces of boiler units

Steam Pyrolysis of Oil Sludge for Energy-Valuable Products

Experimental studies of the steam pyrolysis of oil sludge were performed using a flow-type pilot plant with 300 kg/h capacity (raw material) to obtain energy-valuable products, such as liquid hydrocarbons (30.4 wt%), semi-coke (39.6 wt%), non-condensable gas-phase compounds (26.5 wt%), and bitumen (3.5 wt%). The pyrolysis process was conducted at a temperature of 650 ° C and with a steam flow rate of 150 kg/h. Liquid hydrocarbons were considered a target product. Comprehensive studies of their physicochemical characteristics, atomization process, droplet ignition, and combustion were carried out. The studied sample had physicochemical characteristics similar to traditional fuel oil (calorific value-42.6 MJ/kg, sulfur content-0.8 wt%). The jet spraying angle was 25° in view of the improved rheological properties of the test sample, with a homogeneous jet structure and a predominant droplet diameter of no more than 0.4 mm. The flame combustion process was accompanied by the formation of microexplosions, the frequency and intensity of which depended on the temperature of the air (Tg = 450-700 °C). This study, in view of its applied nature, is of interest in the design of new installations and technological systems for hydrocarbon pyrolysis

Review of coal-water fuel pulverization technology and atomization quality registration methods

Possibilities of coal-water fuel application in industrial power engineering are considered and described. Two main problems and disadvantages of this fuel type are suggested. The paper presents information about liquid fuel atomization technologies and provides data on nozzle type for coal-water fuel pulverization. This article also mentions some of the existing technologies for coal-water slurry spraying quality determination

All-Plasmonic Switching Effect in the Graphene Nanostructures Containing Quantum Emitters

Nonlinear plasmonic effects in perspective 2D materials containing low-dimensional quantum emitters can be a basis of a novel technological platform for the fabrication of fast all-plasmonic triggers, transistors, and sensors. This article considers the conditions for achieving a strong coupling between the surface plasmon–polariton (SPP) and quantum emitter taking into account the modification of local density of optical states in graphene waveguide. In the condition of strong coupling, nonlinear interaction between two SPP modes propagating along the graphene waveguide integrated with a stub nanoresonator loaded with core–shell semiconductor nanowires (NWs) was investigated. Using the 2D full-wave electromagnetic simulation, we studied the different transmittance regimes of the stub with NW for both the strong pump SPP and weak signal SPP tuned to interband and intraband transition in NW, respectively. We solved the practical problem of parameters optimization of graphene waveguide and semiconductor nanostructures and found such a regime of NW–SPP interaction that corresponds to the destructive interference with the signal SPP transmittance through the stub less than 7 % in the case for pump SPP to be turned off. In contrast, the turning on the pump SPP leads to a transition to constructive interference in the stub and enhancement of signal SPP transmittance to 93 % . In our model, the effect of plasmonic switching occurs with a rate of 50 GHz at wavelength 8 µ m for signal SPP localized inside 20 nm graphene stub loaded with core–shell InAs/ZnS NW

Inkjet Printing of Plate Acoustic Wave Devices

In the paper, the results of production of Ag inkjet printed interdigital transducers to the acoustic delay line based on Y-cut X-propagation direction of lithium niobate plate for the frequency range from 1 to 14 MHz are presented. Additionally, morphological, structural, and electro-physical characteristics of the obtained electrodes were investigated. Mathematical modeling of the excitation of acoustic waves by these electrode structures was carried out. Comparison of the theoretical results with experimental ones showed their qualitative and quantitative coincidences. It was shown that conventional inkjet printing can replace the complex photolithographic method for production of interdigital transducers for acoustic delay lines working up to 14 MHz. The resulting electrode structures make it possible to efficiently excite acoustic waves with a high value of electromechanical coupling coefficient in piezoelectric plates

Organic matter accumulation by alkaline-constructed soils in heavily metal-polluted area of Subarctic zone

Purpose: The research aimed to investigate properties and functions of soils constructed from alkaline mining wastes of different origin to remediate the industrial barren resulted from long-term emissions of the copper-nickel factory in the Subarctic region (Kola Peninsula, Russia). Conventional indicators of the remediation effectiveness (pH and metal content in geochemical fractions) were related to the indicators of soil functions such as biomass production, accumulation of organic carbon, microbial activity, and soil respiration. Materials and methods: The experimental area included two sites with polluted and degraded Podzol and Histosol soils located in 1.5 and 0.7 km from the nonferrous (Cu-Ni) smelter, respectively. At the sites, artificial soil constructions were made from mining wastes or quarry sand covered by the vermiculite layer with lawn grasses planted on top. Plant biomass was collected every year starting from the experiment set-up. In 5 to 8 years, soil samples were collected on the layer basis, and chemical, biological, and morphological properties were analyzed. Sequential fractionation of metals was conducted using a modified Tessier’s scheme. The microbial biomass and its respiration activity were determined. Micromorphological studies were conducted using an optical microscope. Soil respiration was measured on-site by IRGA with simultaneous observations of soil moisture and temperature. Results: The plant growth and residues' deposition at both experimental sites triggered carbon accumulation and resulted in 2–3 times higher content of organic carbon in the upper constructed soil layer compared to the initial content in mining wastes. Carbon accumulation was a key driver for the development of soil microbial communities and had a positive effect on the metal immobilization. This effect was strengthened by high pH inherited from the alkaline wastes and resulted in the performance of constructed soils as geochemical barriers. In their upper layers, where the root biomass was the highest, about 30–60% of Cu and Ni were bound by organic matter. In the underlying polluted soil, the most toxic water-soluble metal fraction was completely neutralized; and the metal concentrations in exchangeable fraction decreased by a factor of four improving the habitat conditions of the microbiome. Organic matter accumulation by clay material with the formation of organo-mineral films was found in the vermiculite-lizardite variant. Conclusion: Soil constructions made from alkaline mining wastes in the Subarctic supported the development of plant and microbial communities, organic matter accumulation, and metal immobilization. This technology allows protecting the environment from further pollution under the continuous emissions of the copper-nickel factory

Electrical Resistance Preheating of High-Amperage Cells

На текущий момент нет единого мнения о том, какой способ обжига лучше. В большинстве случаев выбор того или иного способа на каждом алюминиевом заводе определяется рядом объективных и субъективных факторов. Зачастую при выборе способа обжига не учитываются затраты на использование энергии на этот процесс (электрической или от сжигания эквивалентного количества различных видов топлива), что может иметь существенное значение для различных регионов и влиять на себестоимость выпускаемого алюминия. В данной статье представлены результаты испытаний электрического обжига электролизеров опытного участка РА-400 ОАО «РУСАЛ Саяногорск»At present, there is no single opinion on which cell preheating method is best. In most cases, such a method (that is to be chosen for a smelter) is chosen based on a number of objective and subjective factors. It is often when a method is chosen that power expenses (either electricity or power generated from fuel combustion) for such a method are not taken into account. However, it can play a crucial role for different regions and influence the production cost of Al. This paper discusses the results of testing the method of electrical preheating in a pilot cell area (RA-400 cells) at OJSC RUSAL Sayanogors