Influence of Relative Humidity on Ethylene Removal Using Dielectric Barrier Discharge

Abstract

Ethylene gas was decomposed using a dielectric barrier discharge (DBD) plasma reactor for the long-term preservation of fruits and vegetables with a focus on the influence of humidity on ethylene decomposition efficiency. DBD is actively used to produce nonthermal plasma, which is effective in converting C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> into CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O, through an oxidization process with a high reaction rate because the nonthermal plasma in air contains a large number of chemically active species such as atomic oxygen radicals (O) and hydroxyl radicals (OH). This production of radicals depends on the level of humidity in the air. During the experiment, C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> gas was diluted by 200 ppm with an N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas mixture and was fed into the DBD reactor at a 3 L/min gas flow rate. The relative humidity (RH) of the gas was adjusted by the bubbling gas through water. The gas temperature was fixed at 25 °C. The experimental results showed that C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> decomposition efficiency was almost independent of RH.