scholarly journals Ozone Production in Cylindrical Co-axial Double Dielectric Barrier Discharge Ozone Generator

2021 ◽  
Vol 18 (13) ◽  
Author(s):  
Gobinda Prasad PANTA ◽  
Hom Bahadur BANIYA ◽  
Santosh DHUNGANA ◽  
Deepak Prasad SUBEDI ◽  
Antonis PAPADAKI
Keyword(s):  
Flow Rate ◽  
Ozone Concentration ◽  
Applied Voltage ◽  
Gas Flow ◽  
Barrier Discharge ◽  
Ozone Generator ◽  
Gas Flow Rate ◽  
High Concentration ◽  
Electrode Diameter ◽  
Discharge Time

This study developed an ozone generator of a double co-axial cylindrical dielectric barrier discharge system with air, argon, and oxygen as the working gases. The discharge was produced by using a high voltage power supply of 0 - 18 kV and a line frequency of 50 Hz. The flow rate of air, argon, and oxygen was varied from 1 to 6 L/min. A comparison of O3 generation in air, argon, and oxygen using brass as a central electrode was conducted and it was found that O3 concentration was higher in the case of oxygen than in the air and in argon gases environment for given fixed discharge time, applied voltage, and diameter of the brass electrode. This study revealed that the concentration of ozone increased along with the increase in the applied voltage for constant discharge time and gas flow rate. The O3 concentration also increased with the increase in the discharge time at fixed applied voltage and gas flow rate; however, the concentration decreased with the increase in the gas flow rate at fixed discharge time, applied voltage, and diameter of the electrode. A small reactor with a large inner electrode generated a high concentration of O3. Yet, a reactor with a small diameter, there seemed to have an optimum inner electrode diameter. The glass tube reactor of the internal diameter of 18 mm and the brass electrode of diameter 8 mm were utilized in this study. The ozone concentration was higher for oxygen as feed gas than both in the air and in argon and the O3 concentration was also higher in the air than in argon at fixed discharge time, applied voltage, and diameter of ozone generator. HIGHLIGHTS Ozone concentration increases with increasing applied voltage and discharge  time but concentration decreases with increasing gas flow rates Low cost ozone can be produced in DBD reactor at atmospheric pressure Oxygen can be used as feed gas to generate high concentration of ozone than other gases inside DBD generator Optimization of central electrode diameter and gap space inside DBD reactor can help to increase ozone concentration, yield, and efficiency Proper choice of central high voltage electrode also can play the important role for the generation of ozone in DBD chamber GRAPHICAL ABSTRACT

scholarly journals The Effect of Mass Transfer Rate-Time in Bubbles on Removal of Azoxystrobin in Water by Micro-Sized Jet Array Discharge

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1169
Author(s):  
Feng Chen ◽  
Dezheng Yang ◽  
Feng Yu ◽  
Yang Kun ◽  
Ying Song
Keyword(s):  
Mass Transfer ◽  
Removal Efficiency ◽  
Flow Rate ◽  
Applied Voltage ◽  
Transfer Rate ◽  
Gas Flow ◽  
Mass Transfer Rate ◽  
Initial Solution ◽  
Solution Temperature ◽  
Gas Flow Rate

In this work, the azoxystrobin removal in water by using a micro-size discharge array was investigated, and the removal efficiency can reach as high as 98.1% after 9 min plasma treatment as well as the energy utilization being only 0.73 g/(kW·h). Based on the relationship between the generation of gas bubbles and parameters of gas-liquid discharge, it was found that the variation of applied voltage, gas flow rate and initial solution temperature could cause particle number change, mass transfer rate change and the mass transfer time change, which significantly affected the practical applications at last. The experimental results indicated that when gas flow rate was 0.7 SLM (Standard Liter per Minute) and the initial solution temperature was 297 K with the applied voltage of 8 kV and discharge frequency of 6 kHz, the removal efficiency of azoxystrobin achieved maximum. Based on the analysis results of liquid mass spectrometry, the removal pathways of azoxystrobin were supposed by the decomposed by-products. Toxicity tests indicated that the decomposed products were safe and non-toxic. So, this study may reveal an azoxystrobin degradation mechanism and provide a safe, reliable and effective way for azoxystrobin degradation.

scholarly journals Optimization of TIG Welding Parameters for the 202 Stainless Steel Using NSGA-II

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Neeraj Sharma ◽  
◽  
Wathiq Sleam Abduallah ◽  
Manish Garg ◽  
Rahul Dev Gupta ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Flow Rate ◽  
Gas Flow ◽  
Welding Process ◽  
Welding Current ◽  
Welding Parameters ◽  
Shielding Gas ◽  
Gas Flow Rate ◽  
Electrode Diameter ◽  
Weld Region

Tungsten Inert Gas welding is a fusion welding process having very wide industrial applicability. In the present study, an attempt has been made to optimize the input process variables (electrode diameter, shielding gas, gas flow rate, welding current, and groove angle) that affect the output responses, i.e., hardness and tensile strength at weld center of the weld metal SS202. The hardness is measured using Vicker hardness method; however, tensile strength is evaluated by performing tensile test on welded specimens. Taguchi based design of experiments was used for experimental planning, and the results were studied using analysis of variance. The results show that, for tensile strength of the welded specimens, welding current and electrode diameter are the two most significant factors with P values of 0.002 and 0.030 for mean analysis, whereas higher tensile strength was observed when the electrode diameter used was 1.5 mm, shielding gas used was helium, gas flow rate was 15 L/min, welding current was 240A, and a groove angle of 60o was used. Welding current was found to be the most significant factor with a P value of 0.009 leading to a change in hardness at weld region. The hardness at weld region tends to decrease significantly with the increase in welding current from 160-240A. The different shielding gases and groove angle do not show any significant effect on tensile strength and hardness at weld center. These response variables were evaluated at 95% confidence interval, and the confirmation test was performed on suggested optimal process variable. The obtained results were compared with estimated mean value, which were lying within ±5%.

OPTIMIZATION OF NON THERMAL PLASMA REACTOR PERFORMANCE FOR THE DECOMPOSITION OF XYLENE

2016 ◽  
Vol 78 (8) ◽  
Author(s):  
Nor Faraliana Shazwani Nor Azmi ◽  
Abdullahi Mohammed Evuti ◽  
Mohd Ariffin Abu Hassan ◽  
R. K. Raja Ibrahim
Keyword(s):  
Flow Rate ◽  
Thermal Plasma ◽  
Applied Voltage ◽  
Gas Flow ◽  
Plasma Reactor ◽  
Gas Flow Rate ◽  
Reactor Performance ◽  
Model Predictions ◽  
Non Thermal Plasma ◽  
Discharge Gap

Non Thermal Plasma (NTP) is an emerging method used for the decomposition of volatile organic compounds (VOCs). This research focuses on the optimization of NTP reactor performance for decomposition of xylene from wastewater using response surface methodology (RSM) by operating the NTP reactor at applied voltage of 12-15 kV, discharge gap of 2.0-3.0 cm and gas flow rate of 2.0-5.0 L/min. An optimum xylene removal efficiency of 81.98% was obtained at applied voltage 15kV, discharge gap 2.09cm and gas flow rate at 2.36 L/min. The experimental removal efficiencies and model predictions were in close agreement with an error of 0.63%. 

Removal of Toluene by Dielectric Barrier Discharge Combined with Modified Photocatalyst

2015 ◽  
Vol 737 ◽  
pp. 561-564
Author(s):  
Jing Xin Li ◽  
Bao Hui Li ◽  
Zhi Yong Li
Keyword(s):  
Energy Efficiency ◽  
Dielectric Barrier Discharge ◽  
Flow Rate ◽  
Gas Flow ◽  
Barrier Discharge ◽  
Gas Flow Rate ◽  
Dielectric Barrier ◽  
Optimal Doping ◽  
Initial Concentration ◽  
Doping Ratio

The toluene being removed by dielectric barrier discharge (DBD) combined with modified photocatalyst was studied in the paper. Transition metal manganese was doped into crystal lattice of TiO2 in order to improve the activity of photocatalyst, and the optimal doping ratio was confirmed in the study. As one of main factors, the influence on toluene removal efficiency of gas flow rate, initial concentration and electric field intensity was analyzed in the study. Furthermore, the energy efficiency was another important index which had been compared amongγ-Al2O3, TiO2/γ-Al2O3 and Mn-TiO2/γ-Al2O3. The result of study showed that DBD combined with Mn-TiO2/γ-Al2O3 had the best buffer action against increasing of gas flow rate and initial concentration, the energy efficiency had the tendency as Mn-TiO2/γ-Al2O3 > TiO2/γ-Al2O3>γ-Al2O3, and the optimal doping ratio of manganese was 0.01.

Experimental Investigation on Ozone Mass Transfer Coefficient Enhanced by Electric Field in Liquid Phase

2013 ◽  
Vol 864-867 ◽  
pp. 2139-2144 ◽  
Author(s):  
Yang Lin Li
Keyword(s):  
Mass Transfer ◽  
Liquid Phase ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Ozone Concentration ◽  
Total Mass ◽  
Gas Flow ◽  
Electrode Spacing ◽  
Gas Flow Rate

In order to improve the efficiency of ozone mass transfer in liquid phase, the method enhanced by electric field was put forward. The effect on ozone mass transfer was investigated from voltage, electrode spacing and gas flow rate. The result showed that ozone concentration in water and the total mass transfer coefficient increased correspondingly with the increase of the voltage, and ozone concentration in water and the total mass transfer coefficient increased correspondingly with increase of the electrode spacing in the range from 1 to 3 cm, and ozone concentration in water increased correspondingly with increase of the gas flow rate, but the total mass transfer coefficient reduced correspondingly.

scholarly journals Effects of Gas Flow on Spectral Properties of Plasma Jet Induced by Microwave

2018 ◽  
Vol 15 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
Gas Flow ◽  
Microwave Plasma ◽  
Plasma Jet ◽  
Gas Temperature ◽  
Gas Flow Rate ◽  
Argon Gas ◽  
Jet Length ◽  
Maximum Value

In this paper, a construction microwave induced plasma jet(MIPJ) system was used to produce a non-thermal plasma jet at atmospheric pressure, at standard frequency of 2.45 GHz and microwave power of 800 W. The working gas Argon (Ar) was supplied to flow through the torch with adjustable flow rate using flow meter regulator. The influence of the MIPJ parameters such as applied voltage and argon gas flow rate on macroscopic microwave plasma parameters were studied. The macroscopic parameters results show increasing of microwave plasma jet length with increasing of applied voltage, argon gas flow rate where the plasma jet length exceed 12 cm as maximum value. While the increasing of argon gas flow rate will cause increasing into the argon gas temperature, where argon gas temperature the exceed 350 ? as maximum value and study the effect of gas flow rate on the optical properties

scholarly journals Mass Transfer Coefficient of Ozone in a Bubble Column

2018 ◽  
Vol 156 ◽  
pp. 02015 ◽  
Author(s):  
Ratnawati Ratnawati ◽  
Dyah Arum Kusumaningtyas ◽  
Purbo Suseno ◽  
Aji Prasetyaningrum
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Gas Flow ◽  
Bubble Column ◽  
Bubble Column Reactor ◽  
Ozone Generator ◽  
Gas Flow Rate ◽  
State Concentration

The effect of flow rate of ozone-containing gas and pH on the mass transfer coefficient of ozone through water in a bubble column reactor has been studied. Ozone was generated from air using a corona discharge ozone generator. The flow rate of air was varied from 2 to 5 L min-1, while pH was varied from 4 to 10. The gas containing ozone was bubbled to the reactor containing 1.5 L of 2% KI solution. The temperature was set at 28±1ºC. The concentration of ozone was determined using titrimetric method every 5 minutes. The results show that the concentration of ozone increases with time, and it reaches a steady-state concentration after 30 minutes of ozonation. The gas flow rate and pH apparently affect both the concentration and the kLa. The highest kLa of 2.1 X 10-2 s-1 is obtained at pH 4 with a gas flow rate of 4 L min-1.

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