Effect of electric potential across electrodes for trapping joss smoke particles in DBD plasma atmospheric pressure

Particulate matters (PM) in air pollution have been known to be the cause of respiratory diseases. Many researchers have investigated methods of trapping the particulate matter. In this work, the trapping of smoke particles generated from a joss stick by using a dielectric barrier discharge (DBD) system operated under the atmospheric pressure condition was investigated. DBD system consists of an inner electrode which is made of aluminum wire filaments that are placed inside the acrylic cylindrical tube, and the outer electrode is made of metallic wrap around the tube. The electrodes were connected to a 50 Hz high voltage AC source which was adjusted to 0 V, 5kV, 7kV, and 10kV. A ventilating fan was used for draining the smoke particle from the joss stick through the inner electrode with an airflow velocity of 2.68 m/s. The effect of electric field and plasma trapping the smoke particles was investigated. Results from the experiment were further compared with a study by simulation. It was found that the smoke particle density measured by applying an electric potential difference of 0 V and 5 kV was similar; both conditions showed the highest smoke density values. On the other hand, when the electric potential difference was adjusted to 7 kV and 10kV, it was found that the smoke particles density decreased by 90%. The experiment also illustrated when the electric potential difference was increased high enough such that plasma was produced at 7 kV and 10 kV, the smoke particle density released from the tube was similar. Nevertheless, when comparing the mass of particles collected from the inner electrode with the plasma condition, it was found that the mass collected increased more than the operating condition with an electric potential difference of 0 kV and 5 kV without plasma.

Kinerja Metode Elektroflotasi pada Pengolahan Air Limbah Pewarna Tekstil Dispersi

Disposal of textile wastewater above the maximum quality standard into the environment will cause many negative impacts on the ecosystem in the environment. The textile industry utilizes about 2/3 of the total dye products. About 10-15% of the use of these dyes is wasted as waste water. Dispersion dyes are a type of synthetic dye that is relatively widely used in the textile industry. Disperse dyes are insoluble in water and have relatively high chemical resistance. One of the suitable methods applied to treat textile dye dispersion wastewater is electroflotation. Electroflotation works on the basic principle of an electrolytic cell. The performance of electroflotation is influenced by several factors, including the difference in electric potential and the length of time for electroflotation. The purpose of this study was to study the effect of electric potential difference and processing time on the performance of the electroflotation method in textile dye dispersion wastewater treatment. In this study, the electroflotation performance was measured based on the ability of the method to reduce the COD (Chemical Oxygen Demand) value and the color level of the treated textile wastewater. In addition, the specific electrical energy requirements and the value of the decrease in dye concentration per unit of electrical energy are also calculated. The results showed that the optimum conditions for electroflotation were achieved by using an electric potential difference of 12 V and an electroflotation time of 60 minutes. Under these conditions, the COD value and color level of textile wastewater can be reduced with separation efficiency of 88.9% and 93.3%, respectively, with a specific electrical energy requirement of 200 kWh/m3. Meanwhile, the decreasing value of dye concentration per kWh of electrical energy based on COD value and color level were 16293.3 ppm/kWh and 23333.3 Pt-Co/kWh, respectively

Investigation of electric potential difference during the top oxygen blowing in converter

Purpose: of this paper is to investigate the method of monitoring the course of the main oxidation-reduction processes and dust depression during the top oxygen blowing, based on the registration of natural electric potential difference on the lance-metal melt site during the blowing. Design/methodology/approach: Exchange processes in the converter bath take place with exchange of electrons and ions between metal and slag melts and gas phase. Since the processes are far from equilibrium, if to complete the circuit it will be possible to register the potential difference. Investigation was conducted in industrial converters of 60-t capacity at medium-carbon steel smelting. During the blowing the potential difference in the lancemetal bath site, the position of the lance and the dust level after gas cleaning were recorded. Findings: It was revealed that the level and sign of variation of the potential difference in the lance-metal bath site reflects the course of the main oxidation-reduction processes in the sub lance area during melting periods: oxidation of silicon, carbon and iron. The probable course of gaseous oxygen interaction with the metal fusion was discussed. Practical implications: In order to reduce the dust level without slowing down the carbon oxidation process, it was recommended to place the lance at a level corresponded to the potential difference during the active carbon oxidation period 30 % lower than 200-210 mV. The results of heats, conducted with the proposed mode of lance position, showed that the level of dust emission was 16% lower than on the comparative melting. Originality/value: The level and sign of the potential difference is possible to use to select the lance position during the blowing for longer slag foamed state without overflow that ensures a lower level of dust emission.