Abstract

Ozone (O₃) the allotrope of oxygen is a powerful disinfectant and oxidant and nature’s agent for cleansing the environment. Ozone present in nature is only of sub-ppm level. In order to have ozone in large quantities, it is inevitable that same is produced artificially in a machine. In our laboratory, we have devised a novel and innovative plasma device for forming ozone in large quantities of thousands of ppm in oxygen corona discharge. This ozone is useful for various applications, such as, purification of ambient air and potable water, disinfecting food products to increase shelf life, ozone therapy, fumigation of operation theaters in hospitals, sterilization of operation tools and personnel, etc. Applications related to environment protection enjoy carbon credits. In the plasma device of axial symmetry, oxygen corona plasma is formed in between a novel cathode (K) and anode (A) of the diode in which a high electric field around 1-10 MV/m enhanced the corona plasma density. Electrons energized by the electric field collided with the background O₂ which then split into O radicals. The radicals in turn joined other free O₂ molecules and formed O₃. The corona formation and O₃ genesis in this ozone generator are modeled and investigated. Electrons in plume multiplied through primary and secondary ionizations and for typical diode geometry with A-K gap d=10 mm and potential 10 kV resulted in electron densities over 1014-1015 m^-3. This in a cold corona formed in gas pressure in thousands of Torr and wide gaps 10 - 30 mm favored formation of ozone densities over 10¹⁹m^-3. Ozone output as required in different applications is controlled by varying the voltage and current in diode in a range suitable for negligible Joule heating which inhibited ozone genesis. Preliminary experiments on the generator so developed, gave ozone concentrations in hundreds of ppm. 

Key words: Modeling, innovative diode, electron emission, Avalanche multiplication, Poisson field, cold corona plasma, ozone generation, development, experiments, ozone measurements.