Search Results (6)

Electrostatic precipitators (ESPs) have shown promise in reducing particulate matter (PM) emissions, but their potential for simultaneous NOx reduction in small-scale combustion systems remains underexplored. This study focuses on using non-thermal plasma generated in a corona discharge to reduce PM and NOx emissions from small-scale combustion. ESP was specifically designed for a commercially available 15 kW boiler with wood pellet combustion and used with both positive and negative discharge polarity to control emissions without any chemical additives. ESP performance was evaluated across a range of specific input energies (SIE) in terms of particle mass and number concentrations and NOx concentrations obtained by continuous gas analysis. ESP ensured the reduction in PM concentrations from 48 mg/m³ to the magnitude of PM content in the ambient air. The highest precipitation efficiency was observed for particles in the 20–200 nm range. Concurrently, NOx emissions were reduced by up to 78%, from 178 mg/m³ to 39 mg/m³. These results were achieved at specific input energies of 36 for positive and 48 J/L for negative corona, which is significantly lower than those reported for many existing separate PM and NOx control systems. This study demonstrates the potential of ESPs as a compact, energy-efficient solution for simultaneous PM and NOx removal in small-scale combustion systems, offering promising implications for improving air pollution control technologies for small-scale combustion systems. Full article

In the mechanized harvesting of cotton in Northwest China, problems result from the presence of a residual film, and it is difficult to remove the residual film in the cotton processing stage. In this study, a needle roller electrostatic separation device was designed for use with unginned cotton residual films, and a series of experiments was carried out. Through force analyses and charge testing of the seed cotton and the residual film, a theoretical basis was provided for separating them. Taking the residual film separation rate as the response index, the optimal parameter combination was determined with a response surface analysis of three factors and three levels, and a mathematical model was established. The test results showed that the optimal parameter set included a 25.3° corona electrode angle, a 172.3 mm corona electrode distance, and a 5.25 W discharge power. After optimization of the parameters for separation, the average residual film separation rate was 91.7%. This research provides data and technical support for the design of the machinery and the selection of the parameters used in treating machine-picked cotton and separating the residual film. Full article

On the way to reducing emissions released into the atmosphere, there is an obstacle in the form of the emissions of solid pollutants produced by households, namely the burning of solid fuels in small heat sources. In this article, the authors deal with the development of a low-cost electrostatic precipitator, which would be able to significantly reduce the production of particulate matter. This is a tubular precipitator concept, which is enhanced by dividing the precipitation space into four chambers, each of which has an ionization electrode. With the investigated structural arrangement, it is possible to increase the size of the collection area without affecting the external dimensions of the separator. The essence of this article was to focus on the design of an ionization electrode, which, in addition to the function of a negative electrode, would also fulfill the function of a structural element of the proposed geometry. The work contains a technical design for the shape of the ionization electrode, which was subsequently examined using ANSYS Fluent software. The conditions under which a corona discharge will occur on the electrodes and how particulate matter is captured in the separation device were investigated with the help of simulations of the electric field intensity. According to the achieved simulation results, calculations were made for the theoretical efficiency of particle collection, which reached a value of approximately 78%. Full article

Oil–water separation technology has potential applications in wastewater treatment, petroleum refining and edible oil processing. As the ultimate means in oil-water treatment, electrostatic coalescence technology has been widely used in oil fields and refineries. However, the technology has many problems, such as complex processes, electrode corrosion, and the inability to treat high-water-cut crude oil emulsions. Here, we propose a contactless method of oil-water separation by corona discharge. With corona discharge of a needle–plate electrode configuration, the oil droplet diffuses to the ITO glass surface and the water droplet oscillates at the edge of the PET film. Here, such droplet behaviors are described in detail. Based on the motion behavior of the oil and water droplet, we designed an efficient oil-water separation device. After the oil-water mixture passes through the device, the oil content in the oil region can reach 99.25% with a voltage of 8 kV. In addition, the separation speed of the oil-water mixture can also be adjusted by varying the corona discharge voltage. This paper presents a simple and innovative method for oil-water separation. Full article

Corona electrostatic separation can remove inorganic materials from coal, reduce coal ash content and sulfur content and improve coal quality, reduce air pollution caused by smoke dust, SO_X, and CO_X. The performance of corona electrostatic separation technology in cleaning a middle ash medium-ash, high-sulfur coal was experimentally investigated. The electrode voltage, drum rotational speed, and feeding speed were tested, whereas other parameters were maintained constant during the experiment. The results indicate that the performance of this technology in cleaning medium-ash, high-sulfur coal can be improved by optimizing the process parameters. The results demonstrate that corona electrostatic separation is effective for the beneficiation of this grade coal. In addition, the efficiency of coal cleaning is significantly improved by adding the second stage beneficiation to clean the middlings out from the first stage beneficiation. In this study, the first stage of beneficiation recovered 38.00% (by weight) of clean coal (ash content below 20%), and the second stage recovered 48.58% (by weight) of clean coal, improving the overall separation efficiency from 0.69 to 1.74. Furthermore, the sulfur content was reduced from 4.71% (raw coal) to 3.53% (clean coal). Our result show that corona electrostatic separation can effectively reject inorganic sulfur from raw coal, and the two-stage separate is also very helpful for coal purification. Full article

Waste from information technology (IT) and telecommunication equipment (WITTE) constitutes a significant fraction of waste from electrical and electronic equipment (WEEE). The presence of rare metals and hazardous materials (e.g., heavy metals or flame retardants) makes the necessary recycling procedures difficult and expensive. Important efforts are being made for Waste Printed Circuit Board (WPCB) recycling because, even if they only amount to 5–10% of the WITTE weight, they constitute up to 80% of the recovered value. This paper summarizes the recycling techniques applicable to WPCBs. In the first part, dismantling and mechanical recycling techniques are presented. Within the frame of electro-mechanical separation technology, the chain process of shredding, washing, and sieving, followed by one or a combination of magnetic, eddy current, corona electrostatic, triboelectrostatic, or gravity separation techniques, is presented. The chemical and electrochemical processes are of utmost importance for the fine separation of metals coming from complex equipment such as WPCBs. Thermal recycling techniques such as pyrolysis and thermal treatment are presented as complementary solutions for achieving both an extra separation stage and thermal energy. As the recycling processes of WPCBs require adequate, efficient, and ecological recycling techniques, the aim of this survey is to identify and highlight the most important ones. Due to the high economic value of the resulting raw materials relative to the WPCBs’ weight and composition, their recycling represents both a necessary environmental protection action, as well as an economic opportunity. Full article