Athanasios Mermigkas

Superposition of DC Voltage and Submicrosecond Impulses for Energization of Electrostatic Precipitators

This paper discusses the development of an impulsive microelectrostatic precipitation technology, which uses superposition of submicrosecond high-field pulses and dc electric field. Short impulses allow the application of higher voltages to the ionization electrodes of a precipitation system without the initiation of breakdown. These higher levels of electric field generate higher ionic concentrations, resulting in more efficient charging of the airborne particles, and can potentially improve precipitation efficiency. This work is focused on the analysis of the behavior of impulsive positive corona discharges in a coaxial reactor designed for precipitation studies. The efficiency of precipitation of coarse and fine particles has been investigated using different dc and impulse voltage levels in order to establish optimal energization modes.

Removal of Fine and Ultrafine Particles From Air by Microelectrostatic Precipitation

Particles with dimensions less than 2.5 μm (PM2.5) have been identified as being potentially hazardous to human health. The electrostatic precipitation process, which is mainly used in industrial applications, displays a drop in the precipitation efficiency for particles in the range 0.1-1 μm. This paper is focused on the development of an impulsive microelectrostatic precipitation ( μ-ESP) technology for indoor air cleaning applications. Short (microsecond) high-voltage impulses are used in this technology, which allows the magnitude of the electric field that particles experience to be increased without complete spark breakdown occurring and also reduces the energy consumption compared to that of dc-energized systems. The charging process of particles in the impulsive electric field used in the reactor has been analyzed. Ambient laboratory air and air-diluted cigarette smoke, which contain a significant proportion of PM2.5 particles, were used in the precipitation tests. In order to optimize performance for the μ-ESP process, different energization modes of the developed precipitation reactor were studied: dc energization, impulsive energization, and their combination. It has been shown that combined dc and impulsive energization of the two stage μ-ESP reactor produces the maximum precipitation effect. In both cases, ambient laboratory air and diluted smoke, 100% precipitation efficiency has been achieved for fine (250 nm and above) particles; in the tests with diluted smoke, a fine mesh filter was incorporated in the precipitation system to achieve this level of performance.

Analysis of particle charging mechanism for optimisation of precipitation efficiency

The present paper analyses the space charge influenced electric field in a coaxial electrostatic precipitation reactor and discusses the charging process of particles in an impulsive electric field. An analytical expression for the transient non-compensated charge on the particle surface has been obtained. It has been shown that this charge depends of the dielectric properties of the external medium and the particle. The efficiency of micro-electrostatic precipitation process (μ-ESP) in which a combination of DC voltage and high voltage impulses is used to energise the double stage precipitation reactor has been evaluated. It has been shown that this μ-ESP process can provide high removal efficiency for particles as small as 250 nm.

Impulsive corona discharges for fine particles precipitation in a coaxial topology

Air-borne micrometer and submicrometer particles produced by anthropogenic sources contaminate atmospheric air, especially in large cities where both population and industrial activities are higher leading to a reduced air quality. Recent research has pointed out particles less than 2.5 μm in diameter (PM2.5) as a potential health hazard. To address this issue, stricter legislation has been put into force to reduce PM2.5 emissions. This paper is focused on the development of an impulsive microelectrostatic precipitation technology for charging and removal of fine air-borne particles in an economically feasible way. In this paper, a compact coaxial precipitator has been developed for possible indoor air cleaning applications. Highvoltage impulses together with dc voltage have been used for energization of the reactor as it has been shown to enhance the precipitation efficiency. This precipitation system has been used for removal of fumes and fine air-borne particles from ambient air. In addition to the experimental part, analytical work has been conducted to optimize the electrostatic precipitation process and to reduce its power consumption.

The use of impulsive corona discharges for the removal of fine particles in a novel coaxial electrostatic precipitator

Summary form only given. Power plants, internal combustion engines and other sources produce micron and sub-micron particles, which contaminate the air. This problem is faced mainly in large cities where both population and industrial activities are higher leading to significantly reduced air quality. Recent research has pointed out particles less than 2.5 μm in diameter (PM2.5) as a potential health hazard. In the light of these results directives and strict legislation has been put into force in order to reduce PM2.5 emissions. This research paper is focused on an impulsive microelectrostatic precipitation technology in order to charge and remove suspended particles from the air in an economically feasible way. HV impulses together with dc voltage has been used in order to energise the reactor as it has been shown to enhance the precipitation efficiency. In the present work a compact, yet larger in scale, coaxial precipitator has been developed for possible indoor applications. This precipitation system has been tested for removal of smoke and fine airborne particles from ambient air. In addition to the experimental part, analytical work has been conducted in order to optimize the electrostatic precipitation process and reduce power consumption.

Sub-microsecond impulsive corona discharges for electrostatic precipitation applications

The present paper discusses the development of the impulsive micro-electrostatic precipitation technology (μ-ESP), which uses superposition of sub-microsecond high field pulses and DC electric field. Short impulses allow the application of higher voltages to the ionisation electrodes of a precipitation system without the initiation of breakdown. These higher levels of electric field generate higher ionic concentrations, resulting in more efficient charging of the airborne particles and can potentially improve precipitation efficiency. The present work is focused on analysis of the behavior of impulsive positive corona discharges in coaxial reactor designed for precipitation studies. The efficiency of precipitation of coarse and fine particles has been investigated using the different DC and impulse voltage levels in order to establish optimal energisation modes.