Dielectric Barrier Discharge Ozone Research Articles

A novel dielectric barrier discharge ozone generator with excellent microdischarge temperature behavior

In this paper, the electrical characteristics and optical emission spectroscopy of a dielectric barrier discharge ozone generator with water as the grounding electrode are investigated. The gas temperature of the microdischarge channel and at the reactor outlet have also been studied. Results show that the working plasma has a very small effect on the increase in gas temperature at the reactor outlet. At applied power frequency of 5 kHz and applied peak voltage of 7 kV, the microdischarge temperature is obtained as 310 K from N2(C3Πu → B3Πg) spectra ranging from 370-381 nm. In addition, the plasma emission spectra of gas mixtures (95 % O2 + 5 % N2) are investigated and the microdischarge temperature is determined as 309 K with applied power frequency of 5 kHz and applied peak voltage of 8 kV. It is concluded that observed microdischarge temperatures reaches the lowest values reported for filamentary air discharges, capable of promoting ozone production.

A proposed optimized equivalent circuit and performance analysis of dielectric barrier discharge ozone generator

<span lang="EN-US">Traditionally, low-frequency power supplies are used in dielectric barrier discharge (DBD) ozone generators. These generators require a very high output voltage. This may limit ozone production due to limitations imposed by the dielectric strength of the insulating material. Low-frequency generators also present low efficiency, large volumes, and difficulty in controlling ozone production. On the other hand, the advantages of high frequency DBD ozone generators are the increased power density applied to the chamber electrodes, and the voltage applied to the ozone chamber decreases, allowing for higher ozone production efficiency. From this point of view, in order to enhance and control the DBD ozone generator operating at high frequency, it is necessary to determine all parameter values and optimize the equivalent model for this type of generator. This work presents and proposes the practical methodologies used to extract all parameters of the high voltage high frequency (HVHF) transformer which can be used in these systems. Resonant frequency control techniques are presented in this paper. Elimination of the stray capacitance effect will also be implemented in this paper.</span>

Enhancing ozone production in dielectric barrier discharge utilizing water as electrode

Dielectric barrier discharge is widely used in applications such as ozone generation and surface treatment. This investigation studies the electrical diagnostics and ozone generation capability in a dielectric barrier discharge ozone generator utilizing water acting as the ground electrode for the first time. Results show that specific input energy peaks at 8 kHz when the frequency changes from 5 kHz to 10 kHz. Results also show that the maximum ozone generation efficiency reaches 391.66 g/kWh at discharge frequency of 6 kHz. At power frequency of 7 kHz, the ozone generation efficiency reaches 231 g/kWh and the ozone concentration reaches about 12293.59 ppm. In addition, by comparing with the results of previous studies in the literature, it is concluded that the using water flow as the ground electrode can achieve high ozone efficiency at high ozone concentrations. This investigation provides a new method for high efficient ozone production.

Smart Dielectric Barrier Discharge Plasma Decontamination: Spatially Targeted Decontamination With Actuated Ozone Distribution

This study introduces spatially targeted decontamination using a synergistic combination of dielectric barrier discharge (DBD) flow actuation and ozone generation. Here, we relate the spatial distribution of local microbial decontaminations in an enclosure to that of local ozone concentrations caused by DBD ozone generation and flow actuation using two reactors with contrasting flow actuation, the Fan and Comb reactors, run at equal power of 1 ± 0.03 W for 3.5 min. Deviations in ozone concentrations and reductions of Escherichia coli on contaminated coupons over two planes were used to quantify the utilization capacity of the generated ozone to simultaneously disinfect regions of a surface placed in the planes. Results show that uniform ozone consumption by a contaminated target, i.e., targeted decontamination, lowers ozone requirements, exposure times, and reactor energy consumption for its disinfection. Furthermore, a significant positive correlation was found between local decontamination and ozone concentrations with Pearson’s correlation, ρ (34) = 0.64; p < 0.001. Simulated ozone distribution using an experiment integrated simulation method, governed by DBD reactor geometry induced flow actuation and ozone reaction rates, is also presented for predicting DBD actuated spatial decontamination distribution. Our study shows an innovative approach of applying DBD plasma reactors for decontamination using flow actuation and ozone generation to achieve targeted killing with maximized ozone utilization lowering overall ozone dosage requirements, energy requirements, and exposure times.

Application of dielectric barrier discharge for improving food shelf life and reducing spoilage

Dielectric Barrier Discharge (DBD) based ozone therapy is an attractive non-thermal, additive-free and environment-friendly alternative to traditional food processing technologies. Its practical application is dependent on economical ozone generation and optimum ozone dosage. This study investigates the one-time and periodic application of a compact (48 cu. cm), lightweight (55 g), low power, low temperature, DBD ozone generator for treatment of spoilage inocula prepared from combinations of spoiled green beans, grape tomatoes, lettuce and strawberries. A one-time exposure of 126–136 ppm of average ozone concentration produced by the DBD generator over 3 min and 15 min resulted in at least 1 and 4 log reduction, respectively, in microbial colonies present in the spoilage inocula. Daily exposure of 128.7 ppm average ozone concentration over 3 min under similar conditions showed that inhibition through periodic exposure can successfully inhibit the growth of both bacteria and mold species with at least 5 log reduction of microbial colonies. Visual inspection of whole fruits and vegetables with similar 3-min daily exposure showed the potential of ozone therapy to at least double the shelf-life of food products. For the daily exposures, energy required by the DBD ozone generator was calculated as 0.39 pm 0.06 kJ/day.

Effect of Magnetic Field on Multi-parameters of Needle Plate DBD Ozone Generator

ABSTRACT The oxidation of ozone is very strong, and the products of oxidative decomposition will not cause secondary pollution, so the ozone has become widely used. Dielectric barrier discharge (DBD) is the main method of ozone generation. In recent years, the addition of outfield in the DBD is used to improve ozone generation. In this paper, a needle-plate DBD ozone generator with magnetic field enhanced was designed and manufactured. The authors found the magnetic field could significantly increase the number and amplitude of current pulses, discharge current and the discharge power. The magnetic field did not change the initial discharge voltage. With the discharge voltage increased, the enhancement of magnetic field on ozone concentration was more obvious while on ozone yield was very small. The maximum increment of ozone concentration was 35.4%. With the discharge frequency increased, the magnetic field had a more positive impact on the ozone concentration. And with the same gas flow rate increased, the ozone concentration was increased by the magnetic field. Keeping the SIE constant, the ozone concentration and ozone yield at higher discharge frequency was lower than those at lower discharge frequency. With the increase of SIE, the enhancement effect of magnetic field on ozone concentration would increase.

Engineering Aspects and Parameter Evaluation of Ozone Generator

This paper introduces the Ozone generator parameters analysis and its engineering design aspects. Practically, Ozone is successfully used in water treatment applications; furthermore, it can be used to treat the secondary system cooling water in nuclear research reactors. The main element in this process is the Ozone generator; it has many parameters that need to be set at its design. These parameters can be divided into those related to the electrical equivalent circuit of corona dielectric barrier discharge (DBD), those associated with injected gas flow between the two electrodes, and those belonging to temperature of the electrodes. This paper is intended to those parameters that are related to the electrical equivalent circuit which has two standard models: linear and nonlinear. In this regard, the determination of the component values of nonlinear model can be achieved very hardly. To handle such determination, the nonlinear model can be approximately treated as a linear model in an approaching fashion. Based on this approximation, Lissajous plot and differential evolution (DE) methodologies are used for the computation of DBD ozone chamber parameters. Additionally, a new theoretical technique will be presented

Decreasing Iron (Fe) Contaminant from Ground Water for Water Treatment Processed by Dielectric Barrier Discharge Ozone Generator

At the end of the decade, we have been entered to the bad condition for water quality. As well as we know that water is a primary demand for everyone. Ozone is a very reactive oxidant, and it can oxidize any parameters in water quality and then that parameters can be reduced. The principal of electrical discharge ozone generator can produce ozone when the compilation of electricity flow through the electrode, after that the discharge electrons will bound with free air which containing O2 so that O3 (ozone is formed). In the research, electrical discharge for ozone generator was made with high voltage variation are 12 kV, 13 kV, 14 kV. Next, ozone concentration that produced by this generator is contacted to the groundwater sample in Semarang which containing 5, 85 mg/litre iron and not yet required by World Health Organization International Standard for drinking water that is 0, 3 mg/litre. The result shows, the highest production ozone concentration by this generator is 33, 41 ppm and can decrease iron contaminant up to 23% from 5, 85 mg/litre to 4, 53 mg/litre. The lowest production ozone concentration is 2, 85 ppm, and can decrease iron contaminant up to 12% from 5, 85 mg/litre to 5, 15 mg/litre.

Comparative experimental analysis of ozone generation between surface and volume DBD generators

Ozone generation by dielectric barrier discharge (DBD) is widely used in industry. Several DBD configurations can be used to generate ozone, which are classified in two main types depending on the geometry of the electrodes: volume DBD and surface DBD models. The aim of this work is to conduct a comparative experimental analysis between surface DBD and volume DBD ozone generators having a cylindrical geometry. This comparative investigation is carried out not only in terms of ozone concentration and energy efficiency, but also in terms of cooling performance. Two experimental setups were used in this work, one for measuring the ozone concentration (in mg/L) and the ozone rate production (in g/h) and a second for cooling experiments. The obtained results show that although the volume DBD model is the most frequently used in industry, the surface DBD reactor gives better results in terms of ozone rate production and cooling.

Comparative Experimental Study between Surface and Volume DBD Ozone Generator

ABSTRACTVolume Dielectric Barrier Discharge (DBD) is nowadays considered the most effective way for ozone generation in the industry. Some papers were published only on surface discharge reactors applied for ozone generation. This article describes an experimental investigation for the comparison between these two reactor types of ozone generation. Two surface and volume DBD reactors of cylindrical shape were used in the same experimental conditions. Obtained results showed that although the majority of ozone generators are of volume discharge type, the surface DBD presents significant superiority in terms of ozone generation and energy efficiency.

Numerical Study on Heat Flow During Catalytic Dissociation of Ozone in a Dielectric Barrier Discharge Ozonizer

A simple heat flow model is established for numerical analysis of the effect of catalytic dissociation of ozone on electrode surface temperature in a coaxial cylindrical-type dielectric barrier discharge ozonizer. The amount of heat consumed by the ozone decomposition at the electrode surface is determined from the balance of heat flow among the discharge gas, electrode, and cooling water. Our calculation using the experimental data shows that the ozone decomposition by 1.6% in total ozone reaching the electrode surface is required to explain the observed temperature decrease from about 20 °C to 8 °C for a stainless steel electrode, while that by 4.5% is needed to explain the temperature decrease from about 20 °C to 19 °C for a copper electrode. The decomposition rates calculated in the discharge are about two orders of magnitude higher than those measured in gas flow downstream of a similar discharge.

Experimental investigation of a PV solar generator for supplying water treatment process

The paper describes a photovoltaic solar generator to supply a dielectric barrier discharge ozone generator employed for water treatment. This paper reports trials of the equipment and modelling the solar power generation system’s efficiency. The design methodology was used to obtain the optimal set point for the orientation of the solar panel during the passage of clouds which causes the decrease of sunlight and thus reduced ozone production. In Algeria, autumn is characterized by the passage of clouds almost every day which negatively affects the performance of the solar panel. The objective of this paper is to identify the set point and to set the robustness of the process in cloudy weather, by determining the optimal values of the orientation angles (north-south and east-west), in order to maximize the power produced by the solar system. Three ‘centred face-composite’ designs were performed on a laboratory experimental set-up and an optimal point was determined.

Design and implementation of a high‐frequency LC‐based half‐bridge resonant converter for dielectric barrier discharge ozone generator

This study describes the design and implementation of a high-frequency resonant converter based on the transformerless half-bridge inverter topology. The transformer can be omitted because the voltage gain of the ‘LC’ tank circuit (without transformer) is sufficiently high to overcome the initiation voltage and to maintain steady ozone yield. Another important contribution of the work is the increase in operating frequencies, that is, up to 95 kHz. This increase has two main benefits: (i) smaller resonant component values (which lead to a smaller size of converter) and (ii) lower initiation voltage. To validate the theory, the high-frequency power converter is designed and tested on a dielectric barrier discharge chamber. It is shown that ozone yield is improved and the ozone formation starts at lower chamber voltages. The experimental and simulation results are found to be in close agreement and hence to validate the design procedures.

Surface-enhanced ozone dissociation in gas flow downstream of a dielectric barrier discharge ozonizer studied by using catalytic probes

A catalytic probe made of a nickel thin wire is introduced into the gas flow downstream of an atmospheric pressure dielectric barrier discharge ozonizer to examine the ozone dissociation process on a catalytic surface. The probe is placed downstream far from the discharge to avoid the influence of reactive species other than ozone. The measured voltage variation across the probe wire under a constant probe heating current is used as a measure of the temperature variation of the probe surface and the nearby gas temperature. The stainless steel and copper wire made probes are also used to examine the effect of catalytic activity. Experimental results show that, for a low probe heating current of 0.2 A, the temperature of the probe decreases with increasing ozone concentration almost independent of the probe materials due to catalytic dissociation of ozone, which removes heat of reaction from the probe. When the heating current is increased to 1.5 A, the temperature of the nickel probe increases with increasing ozone concentration due to thermal dissociation of ozone followed by surface catalytic recombination of oxygen radicals, which gives heat of reaction to the probe. On the other hand, the temperature of the stainless steel and copper made probes decreases with increasing ozone concentration despite the high heating current due mainly to the low catalytic activities.

The Power Measurement of DBD Ozone Reactor Based on the Quasi-Synchronous Algorithm

Ozone production with Dielectric Barrier Discharge (DBD) is a typical example of the applications of low temperature plasma technology. The most critical process is to inject power into the DBD reactor. But because of the characteristic of DBD reactor, the voltage and current of power supply are distorted severely and make the measurement of input power for DBD ozone reactor even hard. This paper, based on Quasi-synchronous sampling algorithm, establishes the input power measurement systems of DBD ozone reactor and achieves the online real-time monitoring input power of DBD ozone reactor. The experimental results prove that the relative errors of more than 95% is less than0.3% between power measurement system based on Quasi-synchronous sampling algorithm and the measurement data with oscilloscope.

Design and implementation of a low cost, high yield dielectric barrier discharge ozone generator based on the single switch resonant converter

This work proposes a low cost ozone generator which is capable of producing high ozone yield. Its dielectric barrier discharge planar-shaped chamber is constructed using common materials; the electrodes are made of aluminium mesh and copper plate, whereas muscovite mica is used as the dielectric. The availability of thin mica sheet ( <; 1 mm) allows for the lowering of the initiation voltage without the use of discharge gas. The chamber is fed by a high-voltage power supply that utilises the single switch resonant converter topology with ferrite transformer. To validate the idea, an experimental prototype ozone generator is designed and constructed. The generator is fed by a low-voltage DC power supply (8-17 V) and does not require water or air-cooling for its chamber. Despite its small footprint, the maximum achievable ozone yield is 120 g/kWh at 2.0 l/min, with measured efficiency of 75%. Finally, the performance of the proposed generator is critically evaluated in comparison with several important works in the same area.

Effect of pulse power characteristics and gas flow rate on ozone production in a cylindrical dielectric barrier discharge ozonizer

The effect of pulse voltage, polarity, duty cycle, and oxygen flow rate on ozone production is studied in a coaxial cylindrical-type dielectric barrier discharge ozonizer at atmospheric pressure. For a constant oxygen flow rate, the ozone concentration increases with increasing input voltage and is nearly proportional to the ozone production efficiency. The bipolar waveform of the applied voltage results in higher ozone concentration and production efficiency than the unipolar one (positive or negative) regardless of duty cycle. A higher duty cycle increases the ozone concentration slightly for the unipolar voltage, while it affects little the ozone production efficiency for either voltage polarity. For constant pulse polarity and duty cycle, the ozone concentration decreases with increasing oxygen flow rate, however, the maximum ozone production efficiency for each flow rate shows only a minor difference for the change in flow rate. The results confirm that the ozone production efficiency depends more on the pulse power characteristics and less on the oxygen flow rate.

Surface Catalytic Effect of Electrode Materials on Ozone Dissociation in a Cylindrical Dielectric Barrier Discharge Ozonizer

The effect of electrode materials on ozone dissociation is studied by using the electrodes made of stainless steel, copper, and carbon in a coaxial cylindrical-type dielectric barrier discharge ozonizer. The gas and electrode surface temperatures as well as the ozone concentration generated in the ozonizer are measured with varying the applied pulse voltage. The results show that the surface temperature for a stainless steel electrode decreases sharply by more than 10°C as the discharge begins to generate ozone. This is explained reasonably by the dissociation of ozone at the catalytic stainless steel electrode surface, which takes away a large amount of heat from the electrode surface. The decrease of temperature for the less catalytic copper electrode is only about 3°C , and the temperature remains almost unchanged for the noncatalytic carbon electrode. Moreover, the ozone concentrations with the copper and carbon electrodes are approximately twice as high as that with the stainless steel electrode at the same voltage. This is attributed to a decrease in catalytic dissociation of ozone at the copper and carbon electrode surfaces, thus affecting the ozone yield.

Effect of Oxygen Pressure and Flow Rate on Electrical Characteristic and Ozone Concentration of a Cylinder-Cylinder DBD Ozone Generator

A cylinder-cylinder dielectric-barrier discharge (DBD) ozone generator was developed. In order to investigate the optimum conditions for the effective ozone generation in a cylinder-cylinder DBD, the measurements of ozone concentration were carried out for various oxygen pressures and oxygen flow rates. At each condition, the electrical characteristics such as discharge voltage, current, power and their waveforms were recorded. It was found that, for all oxygen pressures, the optimum discharge voltage occurred at an oxygen flow rate of 12 L/min which led to the maximum ozone yield of about 14g/h at an oxygen pressure of 1.1 atm. However, the maximum ozone concentration of about 80g/m3 was obtained at an oxygen pressure of 1.1 atm and an oxygen flow rate of 12 L/min.

Response Surface Methodology Applied to Ozone Generation

In this work, a strategy is presented to optimize the ozone generation by response surface methodology. A dielectric barrier discharge ozone generator was developed in which it is possible to control electrical current frequency and gas flow entering the generator. Response surface methodology was used to identify ozone generator optimum operational conditions, that is, those that permit considerable ozone productivity and high concentration of ozone gas.