Ozone Generation System Research Articles

Application of TiO2 Photocatalyst for Improving Ozone Generation Efficiency

ABSTRACT With a strong oxidizing capability, ozone (O3) is widely used in industry. However, ozone generators on the market are expensive and require a lot of energy to operate, which remains the bottleneck for the wide applications. In this study, a novel and energy-efficient ozone generation system is developed via the combination of black-TiO2 photocatalyst and plasma system. Black-TiO2 catalyst is prepared by calcining commercial TiO2 catalyst at 550 °C under a nitrogen atmosphere to extend the absorption spectrum to visible light range to improve catalytic activity. The experimental results show that ozone generation efficiency can be greatly increased to 415 g O3/kWh via combined black-TiO2 catalyst and plasma with O2 as the feeding gas. This can be attributed to the fact that black-TiO2 catalyst with a smaller energy gap is more efficiently activated to form electron–hole pairs in plasma, which can enhance ozone generation. On the other hand, black-TiO2 catalyst can provide abundant active sites for active O atoms and O2 molecules to promote O3 generation. Black-TiO2 catalyst prepared in this study reveals good stability. Overall, combination of black-TiO2 catalyst with plasma reveals good ozone generation efficiency and has a good potential for practical applications.

Evaluation of an ozone generation system for the control of microorganisms in the indoor air of sanitary environments

Objetive: Evaluate an Ozone Generating System (OGS) through of the microorganisms count and identificated in the air of the sanitary environments of the National Institute of Health (INS) from Peru. The study: These were exposed to OGS for 1 min per m2, air samples were collected at volumes of 200L, 500L and 1000L by impaction, pre and post exposure to OGS, cultures were obtained on Plate Count Agar (PCA) and Oxytetracycline Glucose Agar (OGA) grown at 35°C±2°C for 48 hours and 25°C ± 2°C for 5 days. Findings: A decrease in the count of fungi after exposure to OGS, the difference being statistically significant for the volumes of 200L (p=0.047) and 1000 L (p<0.005); Aspergillus spp. species were identified in most cultures, in bacteria no significant difference was observed. Conclusions: The OGS is a method that inhibits the growth of most fungi in sanitary environments.

Virucidal efficacy of an ozone-generating system for automated room disinfection

Besides conventional prevention measures, no-touch technologies based on gaseous systems have been introduced in hospital hygiene for room disinfection. The whole-room disinfectant device Sterisafe Pro, which creates ozone as a biocidal agent, was tested for its virucidal efficacy based on Association Française de Normalisation Standard NF T 72-281:2014. All test virus titres were reduced after 150 and 300 min of decontamination, with mean reduction factors ranging from 2.63 (murine norovirus) to 3.94 (simian virus 40). These results will help to establish realistic conditions for virus inactivation, and assessment of the efficacy of ozone technology against non-enveloped and enveloped viruses.

Sliding mode control of an ozone generator based on dual AC/DC/AC power converters

The aim of this study was to design a first-order sliding mode controller for dual AC/DC/AC power converters to regulate the production of a corona discharge ozone generator. The design is presented in the two following parts: (a) The first part regulates a three-branch (phase) AC/DC converter to control the DC intermedium voltage that is required to produce the desired ozone concentration, while (b) the second part regulates a one-phase DC/AC power conversion circuit that regulates amplitude of the AC voltage that must be injected into the reaction chamber of the ozone generator. For the first section, the controller regulates the switching sequence yielding the control of the input currents, which defines the amplitude of the DC voltage. In the second, the switching control regulates the amplitude of the expected output AC signal, which depends on the obtained DC voltage from the AC/DC section. This structure represents a novel form to adjust the functioning of the AC/DC/AC power device, which has not been used before in the context of ozone production. Lyapunov’s second method was the main tool for confirming the existence of an asymptotical equilibrium state point for the trajectory tracking deviation for both sections of the power converter. The voltage amplitude was tested on a previously validated mathematical model of a corona-effect ozone generator performance. Several numerical evaluations illustrated the efficient performance of the suggested discontinuous controller and considering the proposed switching sequence that realizes the control action. The proposed controller was contrasted with a usual proportional/integral/derivative (extended state) design, which is a common technique to regulate the ozone generation system.

Toward Efficient Low-Temperature Ozone Gas Sterilization of Medical Devices

ABSTRACT An ozone generation system using V-UV excimer lamps (172nm) and an optical measurement system based on the Beer–Lambert law were developed for an efficient low-temperature (15 °C-30 °C) sterilization of medical devices. Ozone concentrations between 100 and 1ʹ000 ppm (0.2–2 g/Nm3) were generated and the impact of several variables on the sterilization outcome were studied. The survivor curves of the sterilization process were obtained for biological indicators (BIs) inoculated with Geobacillus stearothermophilus spores. A lag phase was observed before the start of the actual sterilization which followed first-order log-linear kinetics. The results demonstrated the feasibility to sterilize medical devices with ozone at ambient temperatures, reducing the consumption of resources and the cost of sterilization.

Development of a Maximum Frequency and Voltage Regulated Power Supply for Ozone Generation System

This paper is proposed full-bridge inverter-based power supply with dynamic PFC converter for an ozone generator. The ozone chamber is required high-voltage range 5KV to 6KV. It derived from AC primary supply 230V with the help of a step-up transformer. The mains supply has variations as a consequence; the output voltage also gets changes. It affects ozone production and also affects the ozone chamber. To avoid the above problem, the regulation of voltage is required. The active boost converter is utilized to direct the dc-connect voltage to improve the input power factor. The voltage control method is utilized to manage the enhanced converter. Thus the projected power supply produces stable voltage and has high performance.

A Wide-Range Frequency Model for Dielectric Barrier Discharge Type Ozone Generators Powered by Series Resonant Inverters

Dielectric Barrier Discharge (DBD) type ozone generators (OGs) are widely used for industrial ozone generation. As OGs are typical non-linear load, different models are presented to analyze the characteristic of OGs and the models of OGs have proven to be an effective tool to design power supplies for OGs. However, most of the models are only applicable to nominal conditions and not suitable for a wide working range at present. Considering that almost all of the series resonant inverters use resonant tanks operating in resonance or near of it, the current through OGs can be substituted by a sinusoidal current source with variable amplitude and frequency. According to the concept, a wide-range frequency model composed of an equivalent resistance in series of an equivalent capacitance for OGs is proposed. Because the equivalent resistance and the equivalent capacitance are closely related to switching frequency of inverter and the current through OGs, the model can be used in the wide working range. Based on the model, the characteristic of OGs is analyzed and a methodology for power supplies is developed. Through a combination of the proposed model and the four limit parameters of ozone generators and power supplies in the methodology, the main circuit parameters of the power supply for maximizing the ability of OGs are obtained. To validate the wide-range frequency model and the design methodology, an ozone generation system powered by a 14-kW series resonant inverter is built. The differences between the experimental results and the analytical results show that the proposed model has satisfying accuracy in a wide working range. Compare to the conventional methodology for power supplies, the main circuit parameters of the power supply can be obtained conveniently regardless of the heavy-load condition and light-load condition of OGs.

Supply Power Factor Improvement in Ozone Generator System Using Active Power Factor Correction Converter

<p>Artificial Ozone Generating system needs High Voltage, High Frequency supply. The Ozonator distorts the supply currents and henceforth affect the supply power factor. This paper presents the performance comparison of PWM inverter to Power Factor Corrected (PFC) converter with PWM inverter based High-voltage High-frequency power supply for ozone generator system. The conventional inverter has front end bridge rectifier with smoothing capacitor. It draws non-sinusoidal current from ac mains; as a result input supply has more harmonics and poor power factor. Hence, there is a continuous need for power factor improvement and reduction of line current harmonics. The proposed system has active power factor correction converter which is used to achieve sinusoidal current and improve the supply power factor. The active PFC converter with PWM inverter fed ozone generator generates more ozone output compared to the conventional inverter. Thus the proposed system has less current harmonics and better input power factor compared to the conventional system. The performance of the both inverters are compared and analyzed with the help of simulation results presented in this paper.</p>

Degradation of Rhodamine B by an electrochemical ozone generating system consist of a Ti anode coated with nanocomposite of Sn–Sb–Ni oxide

An ozonation process was performed using a recycled electrochemical ozone generator system. A titanium based electrode, coated with nanocomposite of Sn–Sb–Ni was applied as anode in a laboratory-made electrochemical reactor. A constant flow rate of 192mg/h of generated ozone was entered to an ozonation reactor to contact with a typical target pollutant, i.e., Rhodamine B (Rh.B) molecules in aqueous solution. Four operational parameters such as: initial dye concentration, pH, temperature and the contact time were evaluated for the ozonation process. Experimental findings revealed that for a solution of 8mg/L of the dye, the degradation efficiency could reach to 99.5% after 30min at pH 3.7 and temperature of 45°C as the optimum conditions. Kinetic studies showed that a second order equation can describe the ozonation adequately well under different temperatures. Also, considering to the importance of process simulation, a three-layered feed forward back propagation artificial neural network model was developed. Sensitivity analysis indicated order of the operational parameter's relative importance on the model output as: time≫pH>Rh.B initial concentration>temperature.

Inductive Power Transfer Systems for PT-Based Ozone-Driven Circuit With Flexible Capacity Operation and Frequency-Tracking Mechanism

This paper presents inductive power transfer (IPT) systems for a piezoelectric transformer (PT) based ozone-driven circuit with flexible capacity operation and frequency-tracking mechanism. The proposed system consists of an IPT circuit as the front stage along with an ozone-driven circuit as the back stage. Considering that the ozone generator system was often used under high-humidity and particle-polluted environment, the study hence proposes a contactless power source such that the oxidization and rustiness can be better avoided. Next, by taking the system expansion into consideration, this paper proposes multiple modular parallel PTs in order to increase the output capacity of the designated circuit. This is further followed by a frequency-tracking control developed to promote power delivery efficiency. To confirm this proposed method, the developed system has been realized with hardware circuit validation. Experimental results demonstrate that the proposed system not only delivers the power effectively, but also ensures balanced output current of each PT, thereby facilitating the approach for the ozone-driven applications.

Ozone Generation Properties of Screw electrode Ozonizer by Different Outer Electrodes

AbstractMethyl bromide which is most popular disinfectant of soil has been prohibited from using except for an indispensable use by 2015. Therefore we pay attention to ozone as a substitute of the methyl bromide for soil sterilization, because the ozone is easily generated by dielectric barrier discharges. We have been developing an ozone generation system which is suitable to the soil sterilization and also investigating the soil sterilization with the generated ozone. So we are investigating influences of ozone generation characteristic on the screw electrode ozonizer by changing of outer electrodes, applied voltages, and flow rates of source gases. This time, in order to investigate the influence of the outer electrode form on ozone generation properties, we used two different outer electrodes; the single electrode of 11cm width and 3-divided-electrodes of 1cmx3(electrode spaces of 4cm). As results, maximum values of the ozone concentration, the ozone yield and the ozone generation efficiency were obta...

Operation simulation of a recycled electrochemical ozone generator using artificial neural network

The present work has focused on the modeling and simulation of a recycled ozone generator system via electrochemical oxidation of water. To produce ozone, a Pyrex glass electrochemical reactor, comprised of two separate half-cell by Nafion 117 membrane was applied. The applied anode and cathode electrodes were Ti/Sn-Sb-Ni and platinized titanium, respectively. The modeling and simulation of the reactor operation were done via artificial neural network (ANN) technique. In this regard, four important operational parameters (i.e. electrolyte concentration, applied voltage, flow rate and electrolysis time) and the generated ozone concentration were considered as the independent inputs and the network output, respectively. To find out the best model, six numbers of three-layered ANNs with different functions were constructed and optimized. Best simulation was related to a model, consist of Levenberg–Marquardt Back propagation learning algorithm (trainlm) and tangent sigmoid (tansig) as transfer function in the both hidden and output layers. Also, application of 10 hidden neurons and 80 iterations for the network calibration caused to satisfy the network training while overfitting was prevented. The K-fold cross-validation method, employed for the model evaluation, showed high correlation coefficient (0.9936) and low mean square error (3.58×10−4) for the testing data. Sensitivity analysis indicated order of relative importance the operational parameters on the ozone production as: time>[electrolyte]>voltage>flow rate.

A New Type of Planar Chamber for High Frequency Ozone Generator System

This paper proposes a new type of planar chamber ozone generation operated at atmospheric pressure, ambient temperature and high frequency. The chamber was constructed in planar type with easy adjustment using simple filler material and arrangement for different type of electrodes. A prototype was developed based on study to find the most effective geometrical electrode shape and dielectric material to produce micro-discharges without additional discharge gas, low pressure and temperature.. The works were initially carried out by theoretical analysis and finite element simulations to find the best geometrical shape for the electrode and to prove theoretical prediction, the experimental works were set up to determine the preferable dielectric to be used along with the electrode. Finally, the best combination was revealed by using muscovite mica and aluminium mesh on copper plate to start generating ozone at 785 Volt and 30 kHz. This planar prototype chamber successfully delivered the highest ozone yield more than 3000 ppm and 120 g/kWh. Due to the simplicity and low cost design, this planar chamber can be suitably used for portable and home appliance.

Implementación de la modulación por densidad de pulsos PDM en un sistema de generación de ozono y su efecto en la curva característica de eficiencia

The ozone generation systems generally use the pulse amplitude modula­tion (PAM) to vary or control the ozone concentration. The results obtained after the implementation of pulse density modulation (PDM) in the power supply system of an ozone generation and the improvement achieved in the efficiency curve is presented in this paper. PAM and PDM techniques were applied in ozone generation system with push-pull inverter resonant self. The adjusted voltage amplitude of the PDM waveform power is de­termined from the condition of the PAM waveform where the maximum efficiency was obtained; Thus achieving increased efficiency in 60% of operating points ozone generation system.

High density ozone generation system using a fuzzy inference engine

High density ozone generation system using a fuzzy inference engine

High Density Ozone Generation System Using Fuzzy Inference Engine

Ozone (O3) is generated by voltage control inverter of single phase sinusoidal waveform different from current control inverter of three phase used in motor control. Ozone quantity is directly proportional to the frequency as well as the voltage of power supply. In this paper, we propose not only a voltage control inverter of 600Hz and step-up transformer from 220V to 12KV using IGBT, but also fuzzy inference engine using MADANI Min-Max composition so as to generate the high density ozone generation. We substantiate that the proposed Ozone generation system produces the double quantity of ozone and higher efficiency than conventional ozone system using the current control inverter through lots of real experiments on the developed ozone system.

Study On The Electro-Chemical Cleaning Technique with BDD Film Anode to Preparation of Electronic Devices

Microelectronic devices are the core of the information products, and one of the key points of it is the cleaning techniques. The cleaning progresses and technology have great influence on the qualities, the price and the competition of the products. The boron-doped diamond (BDD) electrode has a very low capacitance and extreme electrochemical stability, and the BDD electrode was used as anode for ozone generation system through electrolysis of acidic solution. Therefore, the excellent oxidation property of BDD electrode was confirmed and the possibility of further various applications in the cleaning system instead of ozone was expected. This paper presents a new cleaning technology combined electrochemical cleaning, which using BDD film anode with special chemical agents, called electro-chemical cleaning method for short. The principle of the electrochemical progress and some experiment in point was also discussed in this paper.

Safety and quality assessment of packaged spinach treated with a novel ozone-generation system

Abstract The quality and safety of packaged salad are major concerns to consumers. Ozone gas is a non-thermal processing technology capable of treating food to reduce pathogens. The ozone generation system (PK-1) used in this study consisted of a pair of electrodes with an adjustable gap inside a package. Individual, fresh, prepackaged, whole spinach leaves inoculated with Escherichia coli O157:H7 6460 were treated in packaging with ozone generated in air and oxygen. Samples were treated for 5 min and stored at room temperature (22 °C) or refrigeration (5 °C) for 0.5, 2, and 24 h. Gas composition and relative humidity were measured. All treated samples showed reductions in E. coli O157:H7 populations with the largest reductions (3–5 log10 CFU/leaf) after 24 h of storage. After 5 min of treatment, ozone concentrations were 1.6 and 4.3 mg/L for air and oxygen gas, respectively. The concentrations of ozone decreased with time and were not detectable after 24 h. A 5-point Spinach Color Quality (SCQ) scale was established (5-best, 1-worst). Treated spinach showed discoloration with SCQ-values of 3.83 and 1.00 for air and oxygen gas exposed leaves after 24 h. These results indicate that the PK-1 system is capable of reducing E. coli O157:H7 in packaged spinach; however, minimizing quality changes after treatment requires further research.

Effectiveness of Houseplants in Reducing the Indoor Air Pollutant Ozone

Three common indoor houseplants, snake plant (Sansevieria trifasciata), spider plant (Chlorophytum comosum), and golden pothos (Epipremnum aureum), were evaluated for their species effectiveness in reducing ozone concentrations in a simulated indoor environment. Continuously stirred tank reactor (CSTR) chambers housed within a greenhouse equipped with a charcoal filtration air supply system were used to simulate an indoor environment in which ozone concentrations could be measured and regulated. Ozone was injected into the chambers and when concentrations reached 200 ± 5 ppb, the ozone-generating system was turned off and ozone concentrations over time (ozone was monitored every 5–6 min in each chamber) were recorded until about <5 ppb were measured in the treatment chamber. On average, ozone depletion time (time from when the ozone generating system was turned off at ≈200 ppb to <5 ppb in the chamber) ranged from 38 to 120 min per evaluation. Ozone depletion rates were higher within chambers that contained plants than within control chambers without plants, but there were no plant species differences.

Effectiveness of Houseplants in Reducing the Indoor Air Pollutant Ozone

Three common indoor houseplants, snake plant (Sansevieria trifasciata), spider plant (Chlorophytum comosum), and golden pothos (Epipremnum aureum), were evaluated for their species effectiveness in reducing ozone concentrations in a simulated indoor environment. Continuously stirred tank reactor (CSTR) chambers housed within a greenhouse equipped with a charcoal filtration air supply system were used to simulate an indoor environment in which ozone concentrations could be measured and regulated. Ozone was injected into the chambers and when concentrations reached 200 ± 5 ppb, the ozone-generating system was turned off and ozone concentrations over time (ozone was monitored every 5–6 min in each chamber) were recorded until about <5 ppb were measured in the treatment chamber. On average, ozone depletion time (time from when the ozone generating system was turned off at ≈200 ppb to <5 ppb in the chamber) ranged from 38 to 120 min per evaluation. Ozone depletion rates were higher within chambers that contained plants than within control chambers without plants, but there were no plant species differences.