Theoretical And Experimental Research On Ozone Generation By Gas Discharge Plasma

Changes in the structure of the electric utility industry are driving additional reductions of multiple pollutants. Control technologies that are capable of simultaneously reducing emissions of multiple pollutants may offer the potential to achieve this at lower cost and reduced footprint when compared to conventional controls. Recent commercialization and process development efforts have revealed that the ozone oxidation process offers additional benefits beyond its ability to simply remove NOx. These benefits result from the variety of ways the process can be installed and operated, and as consequence, ozone oxidation offers a degree of flexibility not available with processes such as SCR. This paper explores the key question for the simultaneous removal of multiple pollutants by combined ozone oxidation and chemical scrubbing: the high energy consumption of ozone.This paper experimental research on high frequency dielectric barrier discharge ozone generation, and collect the chemical reaction mechanism for different conditions. There are twice as many ozone concentration and ozone yield as business ozone generator. The effect of adding different admixtures to the feed gas were key-point investigated. The addition of impurities He to the oxygen feed gas and the dry air feed gas is shown to inhibit ozone generation. The O₂→O₃ global rate coefficient increases with increasing dry air proportion using mixture of dry air with Ar. In contrast, the O₂→O₃ global rate coefficient decrease with increasing O₂ proportion using mixture of oxygen with Ar. Using Kr as admixture, an increase in the O₂→O₃ global rate coefficient for ozone generation has been observed for increasing concentrations of added gaseous impurity into oxygen or dry air. The addition of even a small amount of impurity SF₆ has been shown to increase the energy yield of ozone, the ozone concentration improve by 2.35 times (11.3 g/m3) at 200 l/h, SF₆/dry air=2.04×10^-2. It offers a new way to obtain high concentration, large yield, high performance-price ratio ozonizer.Ozone synthesis by employing a short duration (-400 ns) of pulsed power with a dielectric barrier employing parallel plates was discussed. The positive pulse has been shown to be very effective for pulsed ozone production, as the streamers propagate to longer distances, and hence, the volume of the reaction zone will be larger, leading to more production of O₃ with more streamer channels per length than using the negative pulse, positive-negative pulse and negative-positive pulse. The positive polarity also trends to postpone the development of the breakdown of the gap due to lower secondary ionization emission from the negative electrode, where the electric field is lower. The difference input voltage waves induce difference corona inception voltage, too. The highest ozone concentration, ozone output and ozone production yield are 83.6 g/m³,19.15 g/h, 985.03 g/kWh in oxygen, and 40.9 g/m³,5.33 g/h, 288.26g/kWh in dry air, respectively. The experiment results show that ozone production by pulsed streamer non-thermal discharges is very effective without significantly raising the gas temperature or inducing arc breakdown between the electrodes at room temperature and atmospheric pressure.This paper put forward the application of dimensional analysis to ozone production by pulse streamer discharge, and dealt with the relation between ozone concentration and most prominent parameters. In this study, the influence on the ozone concentration of the pulse repetition frequency, difference of the peak pulse voltage and the corona inception voltage, gap length, relative permittivity, pressure, gas flow rate and reactor length (or pulse width) have been investigated by means of dimensional analysis. Positive and negative voltages are known to lead to different corona inception voltages, and the formula may be an applicable approximation method for the estimation of the effects of polarity on the ozone concentration through inserting the appropriate voltage into formula. The general trend of the concentration of ozone on parameters that are of importance in its design agrees with the experimental results to confirm the validity of the model.According the research results in chapter 2, the power requirement for ozone generation using dry air with admixture SF₆ is projected to be approximately 1.68 percent of the gross power output. According the research achievements in chapter 3, using single channel mode and double channel mode in dry air, the power requirement are 0.42 and 0.64 percent of the gross power output, respectively. The low temperature ozone oxidation technology can achieve the same NOx and SO₂ removal as electron beam technology, and high efficiency removal of HCl, HF, Hg and some other pollutants. Energy consumption by high frequency and high voltage in dry air with admixture SF₆ and pulsed discharge in dry air are 71.1% and 92.7% less.