A.T. Sobczyk

Investigations of dc corona and back discharge characteristics in various gases

The paper presents investigations of forward and back discharges occurring in air, carbon dioxide, and nitrogen, with plate electrode covered with fly ash. For the glow discharge, the back corona current is lower than for normal corona discharge, but for back-arc discharge, both currents are nearly the same. A dielectric layer covering the plate electrode causes that the arc discharge can start at higher voltages. In the arc discharge, the elements present in fly ash can volatilise due to electron bombardment of the layer.

Dust particles precipitation in AC/DC electrostatic precipitator

Submicron and nanoparticles removal from flue or exhaust gases remain still a challenge for engineers. The most effective device used for gas cleaning in power plants or industry is electrostatic precipitator, but its collection efficiency steeply decreases for particles smaller than 1 micron. In this paper, fractional collection efficiency of two-stage electrostatic precipitator comprising of alternating electric field charger and DC supplied parallel-plate collection stage has been investigated. The total number collection efficiency for PM2.5 particles was higher than 95% and mass collection efficiency >99%. Fractional collection efficiency for particles between 300 nm and 1 μm was >95%.

Electrostatic method for the production of polymer nanofibers blended with metal-oxide nanoparticles

The paper presents investigations of a method of the production of non-woven polymer fabrics with incorporated metal oxide nanoparticles based on electrospinning and electrospraying. Two main configurations of electrospraying/electrospinning systems have been tested: two-step process of electrospinning of polymer solution followed by electrospraying of nanoparticle suspension, and simultaneous electrospinning of polymer solution and electrospraying of nanoparticle suspension. By this method TiO2, MgO, or Al2O3 nanoparticles of the size from 20 to 100 nm were deposited onto electrospun PVC nanofibers.

Al2O3 + TiO2 Thin Film Deposited by Electrostatic Spray Deposition

In the paper are presented the morphology of Al2O3 + TiO2 thin film produced by electrostatic spray deposition method and the results of investigations of its endurance when subjected to thermal cycles and slurry erosion. The film was produced in steam atmosphere by simultaneously spraying of colloidal suspension of Al2O3 nanoparticles in propanol-2 (as a solvent) with the addition of C10H20O5Si (to improve film adhesion) and 1 % solution of butoxy titanium Ti(OCH2CH2CH2CH3)4 in propanol-2 as a precursor of TiO2. Performed investigations showed that Al2O3 particles and TiO2 particles are uniformly distributed within the film, and that the weight content of aluminum and titanium is nearly the same. The thermal tests did not cause any fracture of the film but decreased film adhesion. Decreased adhesion of the film intensified degradation during slurry test.

SUBMICRON PARTICLES EMISSION CONTROL BY ELECTROSTATIC AGGLOMERATION

An alternating electric field charger/agglomerator, in which particle charging and their coagulation occurs in one stage, is presented in this paper. Th e charger/agglomerator is based on an alternating e lectric field charger formed by a set of two discharge electrodes separated by a set of two parallel grids by each s ide of the discharge electrodes. The particles are charged by ionic current in alternating electric field that al lows the charge imparted to the particles to be higher than for DC chargers. Due to oscillatory motion of the particle s between the electrodes, particles of different mobilities c an collide and coagulate. Number fractional collect ion efficiency of PM2.5 particles in semi-industrial scale, two-st age charger/agglomerator with precipitator section was higher than 90%.