Improvement in discharge characteristics and energy yield of ozone generation via configuration optimization of a coaxial dielectric barrier discharge reactor

Dielectric barrier discharge (DBD) has been widely employed in ozone generation.However,the technology still exhibits relatively low energy yield (E_(Y)) referring to its theoretical value.In this work,E_(Y)of ozone generation was improved by optimizing the mesh number,electrode length,and dielectric material in a coaxial DBD reactor with two wire mesh electrodes.Meanwhile,the discharge characteristics were investigated to elucidate the effect of reactor configuration on E_(Y).Results showed that the discharge characteristics were improved by increasing the mesh number,electrode length,and relative permittivity.When the mesh number was increased from 40 to 100,an improvement of approximately 48%in E_(Y) was obtained.Additionally,higher E_(Y) values were obtained using corundum as the dielectric material relative to polytetrafluoroethylene and quartz.Ultimately,E_(Y) in the optimal DBD reactor could reach 326.77 g·(k W·h)^(-1).Compared with the reported DBD reactor,the coaxial DBD reactor with the mesh electrode and the dielectric material of corundum could effectively improve E_(Y),which lays a foundation for the design of high-efficiency coaxial DBD reactor.

The impact of dielectrics on the electrical capacity, concentration, efficiency ozone generation for the plasma reactor with mesh electrodes

This paper presents experimental results concerning the effect of dielectric type on ozone concentration and the efficiency of its generation in plasma reactor with two mesh electrodes.Three types of dielectric solid were used in the study; glass, micanite and Kapton insulating foil. The experiments were conducted for voltage ranges from 2.3 to 13 k V. A plasma reactor equipped with two 0.3×0.3 mm^2 mesh electrodes made of acid resistant AISI 304 mesh was used in the experiments. The influence of the dielectric type on the concentration and efficiency of ozone generation was described. The resulting maximum concentration of the ozone was about 2.70–9.30 g O3 m^-3, depending on the dielectrics used. The difference between the maximum and the minimum ozone concentration depends on the dielectric used,this accounts for 70% at the variance. The reactor capacity has also been described in the paper; total Ct and dielectric capacitance Cd depending on the dielectric used and its thickness.

Numerical investigation on the effect of gas parameters on ozone generation in pulsed dielectric barrier discharge

Pulsed dielectric barrier discharge is a promising technology for ozone generation and is drawing increasing interest. To overcome the drawback of experimental investigation, a kinetic model is applied to numerically investigate the effect of gas parameters including inlet gas temperature, gas pressure, and gas flow rate on ozone generation using pulsed dielectric barrier discharge. The results show that ozone concentration and ozone yield increase with decreasing inlet gas temperature, gas pressure, and gas flow rate. The highest ozone concentration and ozone yield in oxygen are about 1.8 and 2.5 times higher than those in air, respectively. A very interesting phenomenon is observed： the peak ozone yield occurs at a lower ozone concentration when the inlet gas temperature and gas pressure are higher because of the increasing average gas temperature in the discharge gap as well as the decreasing reduced electric field and electron density in the microdischarge channel. Furthermore, the sensitivity and rate of production analysis based on the specific input energy （SIE） for the four most important species 03, O, O（1D）, and O2（b1∑） are executed to quantitatively understand the effects of every reaction on them, and to determine the contribution of individual reactions to their net production or destruction rates. A reasonable increase in SIE is beneficial to ozone generation. However, excessively high S1E is not favorable for ozone production.

Ozone generation enhanced by silica catalyst in packed-bed DBD reactor

In this paper,three dielectric barrier discharge(DBD)configurations,which were plain DBD with no packing,DBD with packed pure quartz fibers and DBD with packed loaded quartz fibers,were employed to investigate the effect and catalytic mechanism of catalyst materials in a packed-bed ozone generator.From the experimental results,it was clear that the DBD configuration with packed pure fibers and packed loaded fibers promotes ozone generation.For the packed-bed reactor,ozone concentration and ozone yield were enhanced by an increase of electric field in the discharge gap with the packed-bed effect.Meanwhile,the enhancement of ozone concentration and yield for the DBD reactor packed by loaded fibers with silica nanoparticles was due to the catalysis of silica nanoparticles on the fiber surface.The adsorption of silica nanoparticles on the fiber surface can prolong the retention time of active species and enhance surface reactions.

Effect of megapore particles packing on dielectric barrier discharge,O_(3) generation and benzene degradation

Recently,packed-bed discharge plasma technologies have been widely studied for treatment of volatile organic compounds(VOCs),due to the good performance in improving the degradation and mineralization of VOCs.In this paper,a coaxial cylindrical dielectric barrier discharge reactor packed with porous material of micron-sized pores was used for degradation of benzene,and the discharge characteristics and ozone generation characteristics were studied.When the discharge length was 12 cm and the filling length was 5 cm,the packed particles in the discharge area significantly increased the number of micro-discharges,and the current amplitude and density increased with the pore size of packed particles,but the discharge power and ozone concentration showed a trend of first increasing and then decreasing.The discharge power and ozone production reached the maximum when the size of pore former was 75μm,correspondingly,the degradation efficiency of benzene was the highest.

Influence of ozone on the rheological and electrical properties of stored human blood

Blood stored in a blood bank undergoes a series of chemical changes and storage lesions. The purpose of this study was to assess the effect of ozone on the rheological and electrical properties of stored human blood. Venous blood samples, obtained from three healthy humans, were treated with different concentrations of ozone （30, 50, 70 and 80 ~tg/mL） for three weeks in vitro. Ozone was generated from portable medical-grade oxygen using elec- trical corona arc discharge. The ultraviolet-visible absorption of hemoglobin in the wavelength of 300-700 nm showed that ozone in this range did not interact with iron ions and it was not toxic below the concentration of 80 ~tg/mL. The changes of blood viscosity were also measured. The electrical conductivity and permittivity, in the frequency range from 5 to 50 MHz, were measured in the control and treated samples subjected to different concentrations of ozone at different stored periods. The results showed that the conductivity and permittivity measurements may serve as a useful indicator in the quality assessment of blood samples stored in the blood bank.